Standup Zone Forum

General => The Shape Shack => Topic started by: Admin on December 24, 2022, 03:40:51 AM

Title: Print to Ride
Post by: Admin on December 24, 2022, 03:40:51 AM
Getting pretty stoked on what is possible in a print to ride scenario.  Here is an exploded concept of a tail wing and fuselage pedestal.  The whole thing can be printed in carbon in one shot and press fit into the fuselage pedestal shown at bottom.  The carbon rod(s) can be inserted into the printed cavities to get your desired flex.  Cavities that follow the wings curves are easy to set up in software and easy to print as well.  Thanks technology!  Stock carbon rods are available in all sizes and are super cheap so no sense trying to duplicate that.

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/321250770_6027089013989492_3508150669658978798_n.jpg?_nc_cat=106&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=TyTElMKYlPQAX_xFdoB&_nc_ht=scontent-sea1-1.xx&oh=00_AfAAJZMYytf-uSe2d0Dl_Ad7kHiJP2IyBzRmhQhtauFqoQ&oe=63AB3CD7)
Title: Re: Print to Ride
Post by: Admin on December 24, 2022, 07:38:30 AM
These bars may be better.  The 2mm bars could go most of the wing length for a 435 wing.

https://www.rockwestcomposites.com/shop/bar-50a
Title: Re: Print to Ride
Post by: PonoBill on December 24, 2022, 08:12:35 AM
Very cool. Rockwest is a handy source, but expensive. Search for Carbon fiber kite rods and tubes. Tubes are lighter for nearly the same rigidity, rods are bulletproof. I've been buying these for years for RC model wings and quadcopter fuselages. The huge volume of these that are sold makes them dirt cheap. 10 200mmX4mm tubes for ten bucks. These are obviously the least expensive part of this effort, but still...
Title: Re: Print to Ride
Post by: surfcowboy on December 26, 2022, 07:57:38 PM
When you starting to print stuff? I wanna hear about the stress tests. If this works it's a game changer. I'm following this across two platforms now. Come on!! Haha
Title: Re: Print to Ride
Post by: Admin on December 27, 2022, 01:05:41 AM
When you starting to print stuff? I wanna hear about the stress tests. If this works it's a game changer. I'm following this across two platforms now. Come on!! Haha

Hah!  I have the first pocketed one set up to print when everyone is awake :).  I am convinced that we can do something really cool with an easy to print CF outer, and a pocketed stiffener or stiffeners (tops 8 bucks per tail wing).  I have a bunch of possible configurations I want to try ranging from very conventional with an insert to freakishly out there :).  That should allow us to really dial in flex as desired. 

I am not at all convinced that some well controlled flex is not beneficial, especially where active pumping is involved.  There are a bunch of related articles that I have found so far.  Interested to know more.
 https://krex.k-state.edu/dspace/handle/2097/41679
Title: Re: Print to Ride
Post by: tarquin on December 27, 2022, 02:02:54 AM
Awesome stuff. I agree on the flex for pumping. Even in the front wing. It must give you some help like when the tip of a paddle blade flexes and snaps back.
 Not good for going really fast though.
Title: Re: Print to Ride
Post by: Admin on December 27, 2022, 04:00:50 AM
Awesome stuff. I agree on the flex for pumping. Even in the front wing. It must give you some help like when the tip of a paddle blade flexes and snaps back.
 Not good for going really fast though.

One interesting thing that I have learned from reading is that vortices are most significant and create the most drag at low speed, high angles of attack and under heavy load.  This all screams opportunity to me.  That is basically the exact scenario of getting airborne in our sports and especially pumping, where angle of attack is steep and changing by the millisecond  under full load and at low speed.  It is somewhat counterintuitive but pretty cool when you think about it.
Title: Re: Print to Ride
Post by: PonoBill on December 27, 2022, 07:56:51 AM
I do most of my printing overnight or when I'm gone. There are some minor fire concerns, but modern printers prevent thermal runaways in various ways and are at least as safe as a coffee maker. All the same, I put my printers on a steel bench with nothing flammable around them and let them rip. Companies like Prusa have hundreds of printers running 24/7 without issue.

The load directions on the wings change substantially between low speed and high. It might be feasible to make a wing that flexes when pumping but doesn't flutter at speed.

I had a firsthand experience with lift vs. angle of attack yesterday. I was winging at Ka'a in light wind. I knew the wind would come up but I got impatient and pumped up my 7.0 CWC. That wing is tough to flip over and I didn't flip it before I got in the water so I struggled a bit to get it flipped. Once I did I had been pushed east from my usual launch spot. I got up and got up onto foil, sheeted in, accelerated, and slammed straight into the stupid bunker (there's an underwater anti-landing bunker left over from WWII). In my defense for that stupidity, yes, I know the bunker is there, but the water is brown and the tide was low. I thought I was clear--I wasn't. Anyway, I took quick look at the foil and it looked OK, so I continued out, and could not get up onto foil unless I had all my weight back on the board. Even then, I couldn't get high enough to clear the swells, which were waist-high at the reef. So I fell and fell. After a lot of flailing around, I came in over the rock garden (always fun) and had to take a blessedly short walk of shame back to my car.

It turns out that whacking the bunker put a nice ding in my front wing, but also bent the baseplate of my mast, which gave me a decidedly negative angle of attack. With all that force it's surprising that it didn't blow the tracks out of the board, but Dave Mel builds some very sturdy boards.

I took the opportunity to do some practical measurements and calculations. Looking at the alpha polar chart of the airfoil I suspect Axis is using, the -4 degree angle of attack I measured with my bent baseplate yielded a 0.0 foil coefficient. I didn't really need to use the foil equation to calculate I had about 0 pounds of lift with the board level (Yeah, I'm reading a lot of articles on wing design)

Title: Re: Print to Ride
Post by: Admin on December 27, 2022, 09:12:46 AM
See what happens when you're iced in.  Keeping myself entertained with this idea. I added the Axis style pedestal I did yesterday to a 450 mm tail, contoured it to match this tails size, set the incidence to -1.5, and made a through cavity/tunnel for some 2 x 16 mm unidirectional carbon bar.  This is getting printed now.  I used one section, which is pretty close to a Wortmann 9% Symmetrical section.

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/322466641_841849387042626_5073683494717490536_n.jpg?_nc_cat=110&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=QqtB5b3F4qMAX9Jr_HW&_nc_ht=scontent-sea1-1.xx&oh=00_AfAe0L7jPyu6F6gQDeIMWknILREKuQFES__8LBHkqMJQVA&oe=63B079CF)

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/322513395_483547190560696_7657941147788579970_n.jpg?_nc_cat=108&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=UQE51ijAK0UAX97PH3P&_nc_ht=scontent-sea1-1.xx&oh=00_AfCmeYoXaD6thW4VXX26_CiqnlWVv5p7ZxiV-fXs3QdOcA&oe=63AF4A1D)

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/322537837_1271772897016546_3465665688012435789_n.jpg?_nc_cat=110&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=BnVAUi-_zM4AX_bFNEM&tn=DHzk3JPtKj3-RU62&_nc_ht=scontent-sea1-1.xx&oh=00_AfBPrLHWpZC49StRKiwhf9eC4Th3lJV0xlVOXp6xHzTfYQ&oe=63B0E3C7)

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/322690577_1190472628242093_2700674523017497697_n.jpg?_nc_cat=110&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=_SgxV7HL7xYAX_fHMeG&tn=DHzk3JPtKj3-RU62&_nc_ht=scontent-sea1-1.xx&oh=00_AfDSjWvNDOKEn-HO6PAlOGBC4C5fwnzShecM7WAGALf2RQ&oe=63AF8E87)

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/322708481_480530910861774_8838803998040076349_n.jpg?_nc_cat=103&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=PAxdYDw099QAX8KHJWU&_nc_ht=scontent-sea1-1.xx&oh=00_AfBax2MzWx-l5k7MGef5LePkimynvuyKhuT_4b3Zlk-Z-Q&oe=63B0A813)
Title: Re: Print to Ride
Post by: PonoBill on December 27, 2022, 10:11:31 AM
Very cool, that should have plenty of beam stiffness. I'm going to have to look at the widths of rectangular bar available. It might be interesting to have multiple tunnels for small bars vertically oriented and use the number and location of the bars inserted for tuning the flex. That would probably be more useful with the main wings.

We'll have to either do a lot of instrumenting and underwater video for testing or find someone who is sensitive to foil performance characteristics who can articulate the differences. My sensitivity is limited to "yeah, it flew" and "no, it didn't".

The road to get down to my flow testing facility (a straight stretch of the Hood River) has actually been paved, so yay, we won't have to risk death to get down there. But it doesn't work well in the spring because of all the glacial till in the water. Visibility 0.
Title: Re: Print to Ride
Post by: PonoBill on December 27, 2022, 10:15:14 AM
You've probably already found tutorials as good or better, but I found this useful for understanding how to use rails: https://productdesignonline.com/fusion-360-tutorials/how-to-loft-in-fusion-360/

The most important issue mentioned is the necessity of ensuring both ends of the rail snap to the profile. If the rail won't snap he uses constraints to make them snap. I've had a lot of trouble getting the lofted surface to connect to the rail. Mine were snapped at the origin but not at the target profile. He also demonstrated the difference in the order of lofting, which I didn't understand, which resulted in some very weird shapes that might be fun to print but are otherwise useless.

The site is generally interesting. The guy is obviously a pro designer.

I also found an interesting hydrofoil foil section. Speer H105. Designed for low Reynolds number foils. There's an interesting article here: http://tspeer.com/Hydrofoils/h105/h105.htm I haven't found a .dat file for it yet but I'll keep looking.

Tom Speer designed airfoils for Boeing and was part of the Oracle AC team. There's some more info on his design on stack exchange: https://engineering.stackexchange.com/questions/36667/what-foil-profiles-does-the-mit-decavitator-or-similar-vehicle-use  That link is a good starting point for a long walk through a lot of posts. It seems Mr. Speer might give us the offsets or a data file in exchange for whatever performance data we can glean. I'm going to have to unearth the Paddle Pod, the data collection system I built for analyzing the Ke Nalu paddles. It has vibration sensors, angle detectors, a very funky load cell made from a ten-buck Chinese digital scale, and other goodies. I've come across it several times when I was searching for other stuff, but if I actually look for it, it might take more time to find than to build another. 

All this searching has led me to create a new online abbreviation: ISIDRC (I'm sure I don't recall correctly).
Title: Re: Print to Ride
Post by: PonoBill on December 27, 2022, 11:22:40 AM
Last but not least it occurs to me that I funded Brother Bobs (stoneaxe) CAM router because I wanted one for foil design but realized he would put it to much better use, and I could ask him to make forms for foils I wanted to build. I've never actually asked for one, but I'm sure he'd be happy to crank some out if print-to-ride turns out to be overly ambitious. He's also a top-level CAD expert--it's what he did for his career, though he seems to be allergic to parametric design since he doesn't do it for a living anymore. The router can cut molds as well as male forms. He can make that thing sing and dance. This was my Christmas present this year--a steampunk humpback.

Title: Re: Print to Ride
Post by: PonoBill on December 28, 2022, 04:11:41 PM
I was talking with Mark Raaphorst this morning and he told me about a manufacturer in Hood River that makes high-end carbon sail battens using high-modulus T700 uni carbon. RBS (Robichaud Batten Systems). I'd never heard of them but Mark said the battens are unbelievably strong and stiff.
Title: Re: Print to Ride
Post by: Dwight (DW) on December 28, 2022, 05:12:12 PM
RBS (Robichaud Batten Systems). I'd never heard of them….


Not buying that one Bill. You’re having a seniors moment. haha. You most definitely know who RBS is. There were the best windsurf battens back in the day. You rig everyday right next to their building.  ;D ;D
Title: Re: Print to Ride
Post by: PonoBill on December 29, 2022, 08:30:43 AM
RBS (Robichaud Batten Systems). I'd never heard of them….


Not buying that one Bill. You’re having a seniors moment. haha. You most definitely know who RBS is. There were the best windsurf battens back in the day. You rig everyday right next to their building.  ;D ;D

Probably, but for a guy as curious as I am I can be incredibly obtuse.
Title: Re: Print to Ride
Post by: Admin on December 30, 2022, 05:22:53 AM
Further down the road we may end up passing our carbon bar(s) or tube(s) through a premade carbon tube or bar which can be used a fuselage.  We can custom make that part later for a slicker integration.  That will give us a bonded carbon T frame which we can slip printed PA-CF tail wing sections onto.  When complete, that will be 2/3 of our puzzle.  There is no reason that we could not later use tapered carbon bar for the wing support as mentioned above.  That may prove super beneficial.  There are a lot of cheap premade carbon bars and tubes available which could serve as a fuse until we make our own.  https://www.rockwestcomposites.com/25502-group

I am getting stoked on this idea.  Here is another thought provoker (not mine) likely a car wing from here: https://www.addify3d.com/product/3dxtech-carbonx-pa12cf-carbon-fibre-nylon/

(https://www.addify3d.com/wp-content/uploads/2021/08/3DXTECH-CarbonX-PA12CF-Carbon-Fiber-Nylon-Foil-Part-2-800x800.jpg)
Title: Re: Print to Ride
Post by: PonoBill on December 30, 2022, 08:09:44 AM
Yikes, you're looking at some crazy expensive printing filament there. A thousand HK bucks for 500g is a little over $300 for 1.5kg. It better be good, and you probably don't want to print a filament change block alongside the part. 
Title: Re: Print to Ride
Post by: Admin on December 30, 2022, 08:30:04 AM
Yikes, you're looking at some crazy expensive printing filament there. A thousand HK bucks for 500g is a little over $300 for 1.5kg. It better be good, and you probably don't want to print a filament change block alongside the part.

Hi,
No, I am not considering the filament.  Bambu already offers the same PA12 and CF but made stiffer with PA6 for a reasonable price.  Just interesting to see their uses and examples.
Title: Re: Print to Ride
Post by: Admin on December 30, 2022, 05:33:09 PM
Here is a highly scientific test of a PA-CF print for the center section of the foil design I posted yesterday.  the carbon bar that would go through this has not arrived yet, so this is not reinforced.  It is also printed at 30% infill so, far from solid.  First balance tester is my grandson at 65 lbs and then my wife at 115.  At 6 inches, this is a relatively short section, but I hope it gives some idea of stiffness and suitability to be used as a pedestal or mount.  I need to tweak this print a lot (and make some changes to the file itself).  An error on my part left it so that only one of the two screws is actually tightened.  🙂.


https://youtu.be/D2ZVULGM4os

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/322740529_1165576120734831_8578035427587978870_n.jpg?stp=cp6_dst-jpg&_nc_cat=107&ccb=1-7&_nc_sid=dbeb18&_nc_ohc=UoH0ssOeR1MAX8qVTGV&_nc_ht=scontent-sea1-1.xx&oh=00_AfCv9EOOc6xAkMwgD05_oXpG-ErxhPjUATsa-CIHMLzRGw&oe=63B61657)
Title: Re: Print to Ride
Post by: Admin on December 31, 2022, 11:53:56 AM
Yikes, you're looking at some crazy expensive printing filament there. A thousand HK bucks for 500g is a little over $300 for 1.5kg. It better be good, and you probably don't want to print a filament change block alongside the part.

Hi,
No, I am not considering the filament.  Bambu already offers the same PA12 and CF but made stiffer with PA6 for a reasonable price.  Just interesting to see their uses and examples.

I was wrong about that.  Looking at the spec sheet for this stuff it is really stiff 7900 MPa.  Wonder if we could print it?
Title: Re: Print to Ride
Post by: PonoBill on January 01, 2023, 08:12:03 AM
It depends on the melting temp, but probably. It will be abrasive, so steel nozzle, and maybe .060 instead of .040, but you probably already have a steel nozzle in your Bambu, and if you don't, the nozzle/hotend combo is 15 bucks.

More importantly, you revealed your charming wife's weight. For most women, you would now be the late admin, but ballooning up to 115 lb is probably not a touchy subject.

Revisiting that wing cross-section above, I'm liking the curved internal bracing. Of course, we'd still have infill to support the overhang (unless we print these things vertically which is a bad idea for strength, as the parts break fairly easily along layer lines).
Title: Re: Print to Ride
Post by: PonoBill on January 01, 2023, 09:10:04 AM
There's a german guy who built some strength-testing gear to test printed parts. He's tested a lot of filaments, including CF-impregnated PC and PA. I'll try to find his data. Or better yet, get him to try some of the more expensive CF stuff. I've read that filaments that use carbon fiber powder are actually weaker but filaments that use stranded carbon test well, I just don't remember how much better they are.
Title: Re: Print to Ride
Post by: Admin on January 01, 2023, 10:24:13 AM
There's a german guy who built some strength-testing gear to test printed parts. He's tested a lot of filaments, including CF-impregnated PC and PA. I'll try to find his data. Or better yet, get him to try some of the more expensive CF stuff. I've read that filaments that use carbon fiber powder are actually weaker but filaments that use stranded carbon test well, I just don't remember how much better they are.

This is likely your dude.  There are a few others as well.  I just posted this on the FB group but, We are at 4420 MPa so stiffer than the stuff he had tested aside from the diamond stuff. Now, this CF above is almost twice as stiff.  Wonder if it is longer strands of fiber.  That stuff is really stiff but my understanding was that it is a no go on our printers.  On the other hand, I am pretty happy with Bambu's PA-CF.
 The part above is 44 grams.  I am liking the idea of varying flex with rods and using them as connectors.  That offers us a lot of options.  I ordered a bunch of carbon rod sizes and variations to test with in pockets.  We can easily do pockets for 5, 4 and 3 mm circular solid carbon rods in the wing above (for instance).  I have all of those sizes coming.  I also ordered a few carbon tubes that could be fuselages for our alien spaceship wings. (mast into front wing).  I am really starting to like that concept and it is starting to come clear how we can do it pretty easily.  I have the wing shape done in fusion but I can't complete it until I know what it will attach to.  Baby steps.

 https://cdn.shopifycdn.net/.../Bambu_PA-CF_Technical_Data...

https://www.youtube.com/watch?v=te0Wwf7Dxj4
Title: Re: Print to Ride
Post by: Admin on January 01, 2023, 10:45:41 AM
One interesting thing is that our filament (finished) is lighter than finished laminated carbon fiber 1.09 g/cm3 vs 1.55 (or greater).  A solid wing of PA-CF is likely lighter than a foam cored wing of laminated CF (and certainly lighter if comparing solid to solid).  We just aren't as stiff.  But, if we can selectively control flex at a level that we like it may be the best option for some uses.
Title: Re: Print to Ride
Post by: PonoBill on January 01, 2023, 12:50:51 PM
I'm making painfully slow progress at Fusion 360 design. Moving along a but better now that I've quit doing general lessons designing boxes and teacups and just jumping into wing designs. This is the "works of primitive man" version of a wing but I think I'll make faster progress now.

What facebook group??
Title: Re: Print to Ride
Post by: Admin on January 01, 2023, 02:23:51 PM
Sweet.  This is the FB Group:  https://www.facebook.com/groups/232666917793846
Title: Re: Print to Ride
Post by: PonoBill on January 01, 2023, 04:27:42 PM
I made a pedestal for the tail to connect a flat wing to an Axis fuselage. Things are moving along a lot quicker now that I've quit fucking around. I'll print it as soon as I get my Prusa fixed. I'm waiting for a part from wherever the heck Prusa is. Prague?

I suspect if the Bambu printed material is strong enough we could print the fuselage as well. Perhaps just make it a shroud for a tube. Incorporate the mounting pedestal and the locking structure to connect to the wing in the shroud. The mast could connect both to the wing with a bit of offset to mitigate drag from the intersection and to the shroud of the fuselage. There are some nice titanium inserts that work well for printed plastic. They hold best if they're inserted in the back side of holes. I'll sketch some of this up tonight.

Given the laydown sled, it would be good to minimize fuselage length. We can print a bunch of lengths and find what works.
Title: Re: Print to Ride
Post by: PonoBill on January 01, 2023, 08:32:08 PM
We are at 4420 MPa so stiffer than the stuff he had tested aside from the diamond stuff. Now, this CF above is almost twice as stiff.  Wonder if it is longer strands of fiber.  That stuff is really stiff but my understanding was that it is a no go on our printers. 

I don't see anything in the print requirement that indicates the Bambu won't print it:
Extruder: 265-285°C check

Bed Temp: 90-110°C check

Nozzle: Hardened steel nozzle with minimum diameter of 0.4mm recommended
You might need to change out your nozzle. I already have a .4 hardened steel nozzle installed.

Bed Prep: Magigoo Bed Prep Adhesive and 3DXTECH Polyimide Tape work best for 3DXTech filaments: Easy to do. I have some good Kapton tape that works well with fancy-schmancy filaments

Heated Chamber: Recommended check

Other: Ideal layer height is 60% of nozzle diameter. Not recommended printing layers smaller than 0.2mm with carbon fiber reinforced filaments.

Sure, OK. Set in software or G-code but that's actually kind of standard.

They also recommend drying at 90 C for 4 hours. I'm not sure whether they mean drying the filament or the finished part. I have a filament dryer but it doesn't go to 90C. I think mine is about 70C max.
Title: Re: Print to Ride
Post by: Admin on January 01, 2023, 11:31:06 PM
Check this out. I was ready to try some but I am not impressed by this at all.  The Bambu CF with PA 6 in the mix is a world better than this.  He is breaking 2-3 mm bars with a little thumb pressure.  My tail wing wingtips fade to a line and I cannot break them, even with serious load (although the tips do flex at this thickness).  Great reviews though and a lot of options.  https://visionminer.com/collections/nylon .  I emailed them for samples.  They are in Beaverton :).   They seem like a great resource.
 This really has me thinking how different each filament can be, even with the same name such as "PA-CF".  I am again majorly impressed with what Bambu is doing.  It is also incredible that his stuff gets a line free smooth finish at steeper angles.  The product looks sintered when finished and it sands to carbon suede.  So nice.

https://www.youtube.com/watch?v=91VH-dU07PQ
Title: Re: Print to Ride
Post by: Admin on January 01, 2023, 11:55:33 PM
I'm making painfully slow progress at Fusion 360 design. Moving along a but better now that I've quit doing general lessons designing boxes and teacups and just jumping into wing designs. This is the "works of primitive man" version of a wing but I think I'll make faster progress now.


Check if you can move your imported root section and your tip section up and down on the Z axis.  If not, try again but don't start on the origin.  Fusion wants to lock you to the origin and it can be a bear to get it to release, even taking the prescribed steps.  Once they are free, you get vertical control over your design.  Are you using loft to extrude?
Title: Re: Print to Ride
Post by: PonoBill on January 02, 2023, 07:26:14 AM
Yes, I'm using loft and rails for the most part, though I extruded the tail adapter and made a tool to cut the complex curves. I'm building the wings on the ZX plane at the origin because the Airfoil Dat to Spline tool works best that way. If you don't use the origin the tool goes a little nutty and puts the airfoil at strange locations. I can move the airfoil when it's off in strange places but there are a lot of odd artifacts if I do that. I just killed all the constraints at the origin to be able to move the wing afterward.

This design process is consuming. I woke up at 3 AM thinking about the fuselage. I'm liking the shroud-over-tube idea. I had the notion of keeping the fuselage minimal, but intersection drag is nasty and completely parasitic. I'm thinking the shroud should wrap around the mast with a deep fillet. The mast would fit into a puka in the wing, with an extension at the root to accept the full length. The wing slots into the shroud, which covers the extension on the bottom of the wing forward to the location of the front screw hole plus a bit to accommodate the screw and countersink, and is the full length of the mast on the top, plus the filet. The wing screws onto the mast with screws through both the shroud and the wing, clamping everything in place. The limitation of this approach is that the shroud would have to be different for each airfoil, but actually, we can standardize on a short center section that wing designs get lofted from, and customize the shroud if that becomes restrictive. As an added benefit the short standard root section also has the extension to accept the mast. Choosing the right foil and chord for this section will be important.

I'd design the shroud as two-piece to make it easy to insert the tube without leaving a hole that needs a plug (or just run the hole through the tail, glue in the tube and then a plug). Just key the pieces together and epoxy the whole thing together with the tube in place.

I'm working on the shroud design using the Axis 19mm mast. I think that's a great mast that has the advantages of being stiff, strong, cheap, and available (in several lengths).
Title: Re: Print to Ride
Post by: PonoBill on January 02, 2023, 08:09:38 AM
VisionMiner looks like a hell of a good resource. Nice to know the Bambu PA CF is so good though. I've read that PA6 is kind of an optimal nylon choice--a good intersection of printability, strength, controlled flex, and durability. I think most nylon gears are PA6: https://plastcom.dk/en/plastics/pa6-polyamide-nylon/

I have a vacuum chamber at the shop for degassing resin and keeping epoxy out of my pump when bagging. I'm not sure it's big enough to fit a spool. If it is I could easily heat it and maintain 100c with a hot plate and thermostat. If not, they're fairly cheap or I can make one out of a pressure cooker (though somehow the Boston Marathon springs to mind) or maybe the Hot Pot that's gathering dust in our pantry in Hood River. My current filament dryer is nice for keeping filament dry during printing--the filament feeds directly from the dryer. I suspect the AMS box is adequate for Maintaining low humidity once the filament has been dried in a heated vacuum chamber if the desiccant pack is big enough and is fresh or recently restored (baked). I'd probably toss the bags into the vacuum chamber with the spool.
Title: Re: Print to Ride
Post by: PonoBill on January 02, 2023, 09:39:18 AM
Incidentally, if you're having any issues with things shifting on the bed, plain old glue stick give the bed better adhesion. Hairspray is even better, and the smell reminds me of the hot girls with big hair when I was 14.
Title: Re: Print to Ride
Post by: Admin on January 02, 2023, 10:53:08 AM
One of the reasons I started looking at the tube fuselages (which I ordered) is that we can go straight from the stock tube to a lovely tube plug which will be printed with the tail wing and bonded into the fuse tube (ferrule style), possibly hardware free.  Because of the magic of printing, that can smoothly be reduced and the wings can come at 90 degrees from the  middle of the sides.  Interference drag should be minimized.  Reading up on this, the status quo for tails, bottom mount and top mount are both bad options. Outside of testing on an existing platform, I would like to scrap pedestals entirely.  Pedestals that end up with the wing resting just above or below the fuse make no sense to me, aside from ease of manufacture.  Lift and Mikes Lab are the only ones taking advantage of these principles as far as I can see.  Do you know if it is best to terminate the "fuselage" mid wing like they are or to carry it past the tail and terminate with a pin?  I couldn't find info on that yet.  Really good info further down the page here and at the links. 

https://aviation.stackexchange.com/questions/80939/why-does-a-mid-wing-aircraft-have-lower-drag

(https://i.stack.imgur.com/CnC88.png)

(https://cdn.shopify.com/s/files/1/0607/3715/9389/products/25GlideBackWing_1Final.png?v=1665513707&width=1800&crop=center)
Title: Re: Print to Ride
Post by: PonoBill on January 02, 2023, 04:20:29 PM
Very interesting--I like it. I'm not sure what you mean by a tube fuselage. I think some of the shroud ideas still make sense for attaching the stub tail fuselage to the wing and mast. I'm a little concerned about the strength and stiffness of the mast-to-tube-to-wing connection. If you mean a tube that's big enough to act as a fuselage then we're more or less on the same page. I'd make the shroud neck down to disappear into the tube a little past the end of the wing extension. The function of the shroud is to improve the connection of the mast to the fuselage, streamline the end of the tube and provide a fillet to fair it into the wing.

We can key the ferrule of the tail stub to the tube to align it and stop rotation. As long as rotation is constrained we could assemble this thing with hot glue and vary the fuselage length by printing longer stubs or changing the tail wing. Like a KeNalu paddle.

According to what I've read the fuselage needs to stop and fair into the wing some distance from whichever edge that terminates the assembly--so before the trailing edge of the tail and before the leading edge of the wing. The primary reference was to the mast location, but there was some mention of the fuselage as well. It looks like the really efficient hydrofoil craft (like the human-powered stuff) is set back about 1/3 of the chord from the edge. This is handy anyway since it's pretty much where we need to locate the mast if we don't connect to the fuselage behind the wing as most foil systems do. It's worth noting that none of the high-efficiency designs do that, but pitch control of these systems is probably done with some kind of surface-sensing wand and an elevator. This was all mentioned briefly on the Tom Speer website and on the airfoil data site I've been using.
Title: Re: Print to Ride
Post by: PonoBill on January 02, 2023, 04:58:41 PM
This is what I drew at 4 AM. I think it would be efficient and takes advantage of what 3D printing can do. It's probably not very clear. The tube is cheated up towards the top side of the fuselage which needs to be thicker since the mast attaches there. This sets the mast back roughly 1/3 of the chord from the leading edge.
Title: Re: Print to Ride
Post by: PonoBill on January 02, 2023, 05:14:24 PM
The front wing shroud could end in a ferrule like the tail, and just plug into the tube.
Title: Re: Print to Ride
Post by: Admin on January 02, 2023, 11:44:42 PM
Very interesting--I like it. I'm not sure what you mean by a tube fuselage. I think some of the shroud ideas still make sense for attaching the stub tail fuselage to the wing and mast. I'm a little concerned about the strength and stiffness of the mast-to-tube-to-wing connection. If you mean a tube that's big enough to act as a fuselage then we're more or less on the same page. I'd make the shroud neck down to disappear into the tube a little past the end of the wing extension. The function of the shroud is to improve the connection of the mast to the fuselage, streamline the end of the tube and provide a fillet to fair it into the wing.

We can key the ferrule of the tail stub to the tube to align it and stop rotation. As long as rotation is constrained we could assemble this thing with hot glue and vary the fuselage length by printing longer stubs or changing the tail wing. Like a KeNalu paddle.

According to what I've read the fuselage needs to stop and fair into the wing some distance from whichever edge that terminates the assembly--so before the trailing edge of the tail and before the leading edge of the wing. The primary reference was to the mast location, but there was some mention of the fuselage as well. It looks like the really efficient hydrofoil craft (like the human-powered stuff) is set back about 1/3 of the chord from the edge. This is handy anyway since it's pretty much where we need to locate the mast if we don't connect to the fuselage behind the wing as most foil systems do. It's worth noting that none of the high-efficiency designs do that, but pitch control of these systems is probably done with some kind of surface-sensing wand and an elevator. This was all mentioned briefly on the Tom Speer website and on the airfoil data site I've been using.

I think we are pretty aligned.  By tube fuselage I mean a simple stock carbon tube.  I ordered a few options to check out.  https://www.amazon.com/gp/product/B08J8FYJ7T/ref=ppx_yo_dt_b_asin_image_o00_s00?ie=UTF8&psc=1. This stuff is very inexpensive (two + fuselages for $60 bucks) has a smooth matte finish, 2 mm walls at 3/4 OD.  That is the same OD as the round back section of an Axis fuse, but at a fraction of the weight.  This is basically a mountain bike carbon handlebar, which is overkill for our need but a good start.  I say overkill because in the scenario I am describing, the mast junction has been decoupled from the fuse entirely.  Ideally, we would do the same ferrule reversed at the front wing, as you have described.   That would mean we could make ultra light, all carbon / PA_CF complete rear wing/fuselage combos without laminating a thing for a material cost of about $50.00.  I am convinced we can make them strong enough for Downwind and Pump and Glide use, which is really where these concepts should shine anyways.

Food for thought:  The plug that joins the carbon fuse tube to the front foil can be male/male and can be a solid pre-made carbon rod.  That would be incredibly strong, we just need the female side on the front wing itself to be super reinforced there.  Possibly we will create a solid carbon block which houses both the mast well and this female receiver port.  It can be nicely faired on top to match the wing contours.  Maybe that will be made separate from the wing, with the wing getting a rectangular well which will accept the block. 

Bambu Studio tells me that the material cost of my 450 tail is $6.50 including all support.  For that price we can print each design in every incidence angle and have shim free tuning for the cost of a round of chi-chi's.  Fuselage tubes are 1.25 meters and will be cut to length so, no problem having a dozen different lengths on hand to easily test our theories about fuse lengths all while keeping things super clean and light. 

Great info on the termination location.  That is easy to do and super clean.  I will get one mocked up and printed.

(https://m.media-amazon.com/images/I/51cZig5UB1S._SL1500_.jpg)

(https://m.media-amazon.com/images/I/51nmg9Yi7KL._SL1500_.jpg)
Title: Re: Print to Ride
Post by: PonoBill on January 03, 2023, 02:21:17 AM
The facebook group looks to be about 30 percent people telling you everything you're doing won't work.
Title: Re: Print to Ride
Post by: Admin on January 03, 2023, 03:41:47 AM
The facebook group looks to be about 30 percent people telling you everything you're doing won't work.

That leaves 70% :). This is what I'm thinking.  I will fillet the edges next so let me know if you see anything glaring.

(https://www.standupzone.com/plug1.jpg)
(https://www.standupzone.com/plug2.jpg)
(https://www.standupzone.com/plug3.jpg)
Title: Re: Print to Ride
Post by: PonoBill on January 03, 2023, 11:31:24 AM
Tres slick. You mentioned on MyFace that you have two high-modulus masts--tanned, rested, and ready. I don't think it's a wonderful idea to use those, They are designed to plug into the Axis fuselage and would make the mast-to-wing joint unnecessarily bulky. The plug is also rectangular which means more material to streamline the connection and interface of wing to mast. The aluminum mast connection is more practical. I've done a dimensionally correct drawing of the mast to start designing the shroud. I also need to settle on a foil design for the connector body for the wings. the mast is not parametric, to get the proportions correct, make the chord length 118.5 mm. I can send you the file if you like.

Title: Re: Print to Ride
Post by: PonoBill on January 03, 2023, 11:55:29 AM
What is the inside and outside diameter of the tube you are designing for?
Title: Re: Print to Ride
Post by: PonoBill on January 03, 2023, 01:04:54 PM
I'm thinking something like this for the wing root. The foil profile and chord for the base of the wing can be anything. Just the root is fixed. The mast buries into the wing root to the centerline. The fuselage shroud would wrap around the mast to give added support to both the mast and the root and turns into a plug.
Title: Re: Print to Ride
Post by: Admin on January 04, 2023, 06:37:35 AM
Nice Bill!  This is where I am at.  This is the whole system as I see it.  The front wing houses the mast well and has a port for solid carbon male/male plug (which is a stock and inexpensive item).  The carbon fuse tube is also stock, extremely strong and very cheap ($60.00 for 1.25 meters) and can, of course, be cut to any length.  The whole 1.25 meter tube is 11.2 ounces.  The tail will be printed in three parts and joined with carbon rods.  It will be a print-to-ride tail.  (it is pictured as one piece but it will be sliced and joined).  The Plug, the fuse and the tail are super light and cost less than $50.00 all in.  The Tails can be printed at any incidence, so it will be easy to carry a few for no-shim angle options.  Same goes for fuse lengths.  The front wing needs a lot more smoothing but these are the broad strokes.

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/323009565_2994714697500631_3792028738311108191_n.jpg?_nc_cat=105&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=fquHRrsFuRoAX8l3M4b&tn=DHzk3JPtKj3-RU62&_nc_ht=scontent-sea1-1.xx&oh=00_AfDPs-qO5dzbPhxz5UIhHhBXM5HPHAoIwNEXUywF2jUm4A&oe=63BA70B8)

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/323426138_856482808802346_6780543634372065431_n.jpg?_nc_cat=106&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=1u05L-_9uVkAX-jGfFQ&_nc_ht=scontent-sea1-1.xx&oh=00_AfCgyWebCQQRgAJzGMHawItGZIZmy6Cog1wDSk0UqaA1ig&oe=63B9B07C)
Title: Re: Print to Ride
Post by: PonoBill on January 04, 2023, 08:42:23 AM
Yes, same ideas.

I was thinking of the root section as a point of origin for designing wings with a core that we can modify and optimize for whatever strength the wing/mast junction requires. We might keep the root section foil (Eppler E836 Hydrofoil) constant and symmetrical but the transition piece from the root to the wing foil can be any foil section and chord we choose. I'm probably overthinking that, or at least stuck more in an assembly mind frame than the freeform approach that 3D printing permits. The only real benefit to an assembly approach is the consistent location of any supporting tubes. We're almost certain to need to print the main wing in 200 mm sections and glue the wing together over rods.

Here are this morning's sketches. The print material extending up into the mast is a happy accident, but I like the idea of a plug extending up into the mast. The shroud dimensions are obviously wrong, the body section would end to flow into whatever diameter the fuselage tube turns out to be. I think it would be structurally beneficial to have the tube insert into the shroud as well as have a ferrule (like the mast connection). That kind of connection probably has a name but I don't know what it is. I'd bring the tube forward inside the shroud until it reaches the mast with the internal ferrule the same length as the extended body of the shroud:


Title: Re: Print to Ride
Post by: PonoBill on January 04, 2023, 04:01:52 PM
Hopefully this makes the idea a bit more clear. The tube shown is a Rockwest 3K with a .375 (9.524mm) ID and .495 (12.57mm) OD. I used the tube as a tool to cut the shroud so it can slide in with both an internal ferrule and outside cover. This should make the joint very strong. We initially had a problem with ferrules breaking with Ke Nalu paddles. We solved it with an internal reinforcement strip of carbon perpendicular to the paddle blade that was embedded in the foam and went from the tip of the ferrule to the base of the blade. It was a pain in the ass, adding a step to the fabrication process.

The solution here would only be reasonable with a 3D-printed part.

The tube slides in to within about 1/2" of the mast. We'd probably print the whole part with 60 to 100% (solid) infill.

Where did you find a male-male carbon plug? I've researched a bit and can't find anything that isn't related to gay porn.

Title: Re: Print to Ride
Post by: PonoBill on January 04, 2023, 05:49:40 PM
Raining like hell, no wind. So I'm screwing around.
Title: Re: Print to Ride
Post by: surfcowboy on January 04, 2023, 06:40:03 PM
This is all looking really cool guys.

I think this wing/fuse/mast thing is really cool. What's the reason everyone puts the wing out in front of the mast anyway? I know ride engine/slingshot had a foil you could mount like this for Wind Foiling I think, right?
Title: Re: Print to Ride
Post by: PonoBill on January 04, 2023, 09:24:00 PM
Actually, the Axis Advanced fuselage puts the mast in almost the same place.
Title: Re: Print to Ride
Post by: Admin on January 04, 2023, 11:53:34 PM
This is all looking really cool guys.

I think this wing/fuse/mast thing is really cool. What's the reason everyone puts the wing out in front of the mast anyway? I know ride engine/slingshot had a foil you could mount like this for Wind Foiling I think, right?

There are some products that use partially wing-enclosed mast mounts.  One in kiting uses no tail wing and is a true mast integrated flying V.  Super interesting, but also very limiting and not for me.  The ones with stabilizers have alway been done with spade style wings (super low aspect) where the leading edge is super swept and the trailing edge flat to meet the mount.  These were commonly used as a two mast position, entry level / budget type wings that had very little faring, etc.

Have a look at this: https://www.ecalc.ch/wingdesigner.htm .  Change just the sweep from the default of 15 to 0 and see what happens to AC.  It moves forward dramatically.  This is what happens with higher aspect straighter wings (most current wings) This is why spade wings are not well suited for this design.  If the mast is one with the wing, that moves the whole wing towards the tail of the board (if nothing else is changed).  If you also have a spade style wing moving things further back, that is not great, especially for short tracks.  Now think of it from a current wing perspective.  As things have moved toward lower sweep, higher aspect forward AC/CL wings, we have also seen a rise of advance fuselages, etc. which pulls that back again. This is an extension of that.

They call it the "advance" fuselage because they are looking at it from the perspective that the mast advances closer to the front wing.  From my perspective it is the "retreat" fuselage.  If the mast stays in the same location in the tracks, the front wing moves back.

This design is selfish.  All about the Swim Missiles and soaring.  What would a complete kit look like if there were minimal power going in, low drag was critical and enough lift was available at swim-in , no-wave, minimal-pump, downwind-swell speeds?  How could we reduce vortices at these low speeds (where the are the most detrimental)?  How could we improve stall characteristics?  What could be done to exaggerate weaker arm/body pumping?  With my research so far, and borrowing plenty from the great products that we have all had access to,  this is my best guess.  It is still far from even V1 :). This is simply what I have adjusted and made buildable since this: https://www.standupzone.com/forum/index.php/topic,38282.msg438284.html#msg438284
Title: Re: Print to Ride
Post by: Admin on January 05, 2023, 03:00:37 AM
Bill, that is sweet.  We have so much more real estate with the front wing for support and locking that we have a ton of options.  It is shocking how stiff even a cheap 5 mm pulltruded carbon rod is, and we have room for much larger stuff here. The design I posted is an 1100 that fits between an Axis 1150 and ART 1099 in terms of both area and volume.  Obviously the area near the root has the majority of both.  That leaves us a lot of room for reinforcing the mast and making sure that the unwanted flex types are minimized.  I also left a vertical portion to the exposed mast well.  That is going to be used for horizontal hardware to completely secure any mast slop wit no shimming.  I have a model built which is really cool but needs tweaking.  I think there are a lot of baby gains that we can make that may add up when fully realized.  :)

On reading, it is clear that I need to improve my wing/fuse fillets but I painted myself into a little corner there in Fusion.  I need to correct that.
Title: Re: Print to Ride
Post by: PonoBill on January 05, 2023, 09:25:07 AM
Yeah, I tried to add fillets at the wing/shroud and shroud/mast junction but Fusion gave me errors with impenetrable reasons. Popping the tip up in the dialog just said "try a different fillet" more or less--not much help. I'm a little concerned about a filet around the mast anyway. A very tin fillet lip would be prone to breaking.

Bambu says my new printer is on the way. This being outer Rangoon in Bora Bora I may see the printer in time to ship it to Hood River. The Prusa I have here is suffering from extreme blobbing. I'll fix it, but this is the kind of crap that Bambu has solved by going to an integrated hot end/nozzle that a lot of printing dweebs are whining about. 15 bucks for a solution that slips in with 2 minutes of fiddling and works every time vs. 5 bucks for a nozzle that might take you four hours to repair after applying too much torque shifts the hot end in the extruder body and the blazing hot nozzle (the only way to get them off once melted plastic has flowed through them) burns you a few times. Then again, economics is rarely a strong suit for geeks.
Title: Re: Print to Ride
Post by: PonoBill on January 06, 2023, 10:07:17 PM
I'm going to print this as soon as my printer shows up or the new parts for my Prusa arrive. I think it has potential and I want to see what kind of dimensional accuracy I can hold. Might have to loosen things up. I'm working on a wing for this, basically a 999 clone. It will have to be printed in four sections plus the root section unless I farm it out to a shop with bigger equipment.



Title: Re: Print to Ride
Post by: Admin on January 07, 2023, 02:36:59 AM
Here is one of the prints I did yesterday (I keep seeing little things that I want to improve).  I am really happy with this direction.  I can get two 4 mm bars in with no problem.  The tolerances are very good for solids, but cavities do retract a fraction, even when supported fully.  It is easily adjusted for, but may require a few test prints.  The result is very exciting.  This is going to work.  The fuse attachment is super strong and stiff.  The prints are clean even without sanding (although, I will sand) and it just screams "ride me".  Bambu tech support has been very patient with me and has coached me through a lot of settings and tweaks, many of which I would have never suspected.  The issue there is that the setting name and description often does not match what the setting does (or what real value it offers).  They also essentially advised to unlearn what you know about printing with other materials.  I am forcing myself to take the time to get each part right, but that is made easier by a frozen Gorge. 

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/324081299_5290547364380084_5045014006967161182_n.jpg?stp=cp6_dst-jpg&_nc_cat=105&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=dSFKwO1IKb4AX8mhmwD&_nc_ht=scontent-sea1-1.xx&oh=00_AfAAqyhxgQf6jytH3lPvVlE96eVKM_YMPZ4PsKkMget-2g&oe=63BEAE30)
Title: Re: Print to Ride
Post by: Admin on January 07, 2023, 06:12:48 AM
In also added collar guides on both sides that can mate to small fuse notches.

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/323273133_1098076210887706_5217866099752145194_n.jpg?stp=cp6_dst-jpg&_nc_cat=103&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=1bOuTNo0YHsAX_K__5A&_nc_ht=scontent-sea1-1.xx&oh=00_AfCV-F454htIMnRp1V65NZasrg1u0ZTyFIjLVOzEISlpIw&oe=63BF19C9)
Title: Re: Print to Ride
Post by: PonoBill on January 07, 2023, 09:57:21 AM
I'm pulling my hair out trying to get splines to work as guide rails with the airfoils generated with Dat to Foil. I'm getting the error that the rails are not connected to the foil profile even tough they're snapped to the ends. I tried adding a construction line through the middle of the foil to be certain I have a snap to connection but no dice. WTF.
Title: Re: Print to Ride
Post by: Admin on January 08, 2023, 08:16:05 AM
First press fit today.  No glue or sanding yet.  I learned a ton from this and I (again) see a lot of ways to make this better.  I figured out how to get my 4mm carbon rods (which are a bit over) into my cavities (which are shrinking to a bit under) with a super snug fit.  I was concerned about placing the rods too close together, which I thought might compromise strength. but no more.  I see now that I can get can get four 4mm bars in each side with great coverage.   Stoked on that!  I also need to clean up the trailing edge in my file.  It is still to thin for the printer to manage well.  Next up I need to figure out how best to glue and finish.  I am wide open to suggestions on super durable adhesives, etc. 

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/324730386_732289911870720_5307294444201760631_n.jpg?stp=cp6_dst-jpg&_nc_cat=102&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=5wVjMkBEY2EAX8JBg6I&_nc_ht=scontent-sea1-1.xx&oh=00_AfBfKJytMapIBqDlxzH65Un-h0L26Hm85pGqeuIkNTusCw&oe=63BEFC9C)
Title: Re: Print to Ride
Post by: LaPerouseBay on January 08, 2023, 08:25:38 AM
I am wide open to suggestions on super durable adhesives, etc. 

https://www.sika.com/en/brands/sikaflex.html
Title: Re: Print to Ride
Post by: tarquin on January 08, 2023, 09:03:20 AM
Epoxy. Sika is good for some things for sure. But very messy and hard to clean up. It's quite thick and not great for tight tolerances.
 Is this to glue the sections of wing together?
 Great progress
Title: Re: Print to Ride
Post by: Admin on January 08, 2023, 10:57:56 AM
Hi Guys,

Yes, this will be for the rod holes and joining the gaps.  Also interested in some leveling if need to smooth the seams and possibly a light surface sealant.

Thanks
Title: Re: Print to Ride
Post by: PonoBill on January 08, 2023, 02:15:40 PM
I've used just typical glassing epoxy to seal the surface of 3D prints. It works about as well as hot coat usually works, which means some pinholes remain. I tried kind of a modified WEST treatment (Wood Epoxy Saturation Technique), Let's call it PEST (Plastic Expoxy..., I coated the part with a heavy hot coat of epoxy with medium fast hardener and stuck it in my vacuum pot. Drew a vacuum on it and watched the bubbles come through the surface. When I held the vacuum at about 15 inches of mercury the bubbles stopped and I let air in. The idea is to have air pressure shove the epoxy into the porous surface. It works--sort of. The surface got a fairly dry. I let it kick and then stuck the part in water. It took up a lot less water than it does untreated, but it wasn't perfect. I did it again and did a second hot coat over it, and that one was completely waterproof. It's a bit of fucking around, and I don't have anything big enough to do a wing, though I could certainly weld up a suitable chamber out of heavy steel pipe, plug one end, and weld a removable flange on one end--or maybe glue something up out of heavy plexiglass tube (which gave me a flashback to the Wilson Cloud Chamber science project I did when I was 14. Fuck, that's 62 years ago--depressing). Load it like an autoclave.  The Faux Drive nosecone in the middle of the picture is PC-CF with both PEST and a hotcoat. I added a through-bolt after coating because I had a problem with some of the nose cones splitting when I tightened them onto the mast (the clearance between the mast and the cone was too tight). The orange drive base attached to a motor is PETG with just PEST. It sucks a tiny bit of water--added about 3 grams after soaking overnight. The cone on the right is PC-CF with no treatment.

If left untreated, these parts suck up water like EPS, though when you take them out of the water it slowly dribbles out and will dry completely with no weight gain after a few days of drying. It probably wouldn't dry as completely with saltwater since the salt and minerals left behind are hygroscopic.

Yikes, I looked up what 3 feet of 8"X .250" plexiglass tube would cost and it's about 900 bucks.
Title: Re: Print to Ride
Post by: PonoBill on January 08, 2023, 06:59:07 PM
So this is kind of interesting given my current struggles with attaching spline rails to the dat to spline-generated airfoils. I'll figure it out eventually, but here's a quick and dirty workaround. A wing design from winghopper that I whipped up in a few seconds and stuck the shroud and mast onto. Kind of cool. I might have problems slicing it up into printable chunks and adding in the holes for the stiffening rods, but maybe not.

Title: Re: Print to Ride
Post by: Admin on January 09, 2023, 12:46:43 AM
So this is kind of interesting given my current struggles with attaching spline rails to the dat to spline-generated airfoils. I'll figure it out eventually

Sorry Bill, I thought I had posted this before!  The key thing is that order that I mentioned by phone.  It is super critical that you go in that order and there are like 30 quirky little things that need to happen.  The rails have to be fully functional and the original foil profiles need to be completely moveable in (both in all 3 dimensions) and getting there is super specific.  Have you picked up that your view angle will allow or disallow certain options (yes, the angle at which you are viewing from!)?  In your design what points on the profiles are you attaching to?
Title: Re: Print to Ride
Post by: PonoBill on January 10, 2023, 10:27:50 PM
This has driven me nuts, but I can finally loft a wing between two foils and have rails work. This shouldn't have been so hard. I've determined that running Airfoil Dat To Spline optimizer makes it much more certain that rails, especially splined rails, will be attached to the foil shapes.
Title: Re: Print to Ride
Post by: PonoBill on January 12, 2023, 10:18:04 AM
Rod placement is going to be tricky, especially with anhedral or foil profile changes. This center body is Eppler E837, a symmetrical hydrofoil profile, the wing section translates to Eppler 818 with no anhedral. Just the reduction in chord (which scales down all dimensions) and the camber of the 818 has the rod toward the trailing edge waving around in space.
Title: Re: Print to Ride
Post by: PonoBill on January 12, 2023, 10:34:03 AM
Damn, even moving the rod a bunch left a notch, and it's going to get worse as the chord decreases
Title: Re: Print to Ride
Post by: Admin on January 12, 2023, 12:41:30 PM
Damn, even moving the rod a bunch left a notch, and it's going to get worse as the chord decreases

Have you contoured your cavities to match the wings shape or angled them in?  level and straight won't work for long.  What diameter tubing are you using?  You can vary tube diameters as needed or change shape.  You should order a bunch of carbon products to feel how stiff this stuff is at each diameter or dimension.  You may be greater than required. 
Title: Re: Print to Ride
Post by: PonoBill on January 12, 2023, 08:36:49 PM
So how are you making curved holes? I guess I'd try something with the shell feature. I was trying 5mm for the tube size. I think it might be worthwhile to use the tubes close to the centerline and print-in reinforcement when/if a straight tube becomes impractical. I'm not sure how to convince a slicer to make some solid ribs, but there has to be a way. 

For any tapered wing, as the chord decreases the lift (and therefore the force applied) further outboard of the wings decreases. We'll probably have to break a lot of stuff to really understand what the limitations of Print to Ride actually are.

On the bright side, even with a fair amount of experience with 3D printing, I'm surprised at how strong these parts are. I printed the center section shown above today and then tried to destroy it. I didn't do anything to strengthen the part and it took my weight with no indication of flex. That will be a bit different with longer sections, but I think we can make some fairly strong wings this way.

If nothing else I'm learning a lot.
Title: Re: Print to Ride
Post by: Admin on January 13, 2023, 01:37:38 AM
Hi Bill,

I see a few things.  There is a lot of disparity between your two profiles.  You are going from 16.1% at 36.9 to 9.4% at 33.  Those are unconventional numbers at both ends for front wings.  It is going to be harder (but possible) to join there.  It will be much easier to join after the transition.  The 9.4 percent combined with the extreme contours of the main profile are going to add challenges.  If those holes are 5 mm then you are looking about 1 cm or a touch over for max thickness at 6 to 8 inches off of the root.  That is very thin.  The thinnest foil I have here is 2.4 cm at that same spot, and those carry their thickness much further out in both directions.  Also when existing foils are using a symmetrical thicker profile at the root, it is exactly matching the main profile for the top half.  The bottom is a mirror of the top.  That leaves an even top contour for the whole span.  That would also make joining (even with thicker rods) much easier)

To contour the cavities, you can use the guide sketches for your lofting as paths but 5mm tubing essentially has no usable flex.  It is going to fight you at joining for any curves.

I am not suggesting that you follow convention or modify your design to make it easy.  I dig it!  The whole point is exploration and "what if?"  That is where the fun lies.  If we want what already exists we can buy it.  There are a ton of great options. 

This PA-CF is super stiff and light and all of the carbon samples I have here are surprising as well.  I have had to completely rework what I had planned because we are dealing with so much more stiffness than I had conceived.

My Bambu has been running nonstop and I have done a silly amount of models, protos, tools, and refinements.

I have been making tools (jigs) to help me cut the notches, etc for interlocking and aligning the carbon parts with accuracy.  I also spent a few hours talking to various bonding solution mfg's and have a bunch of samples coming to test the adhesives which they are suggesting for our specific plastic to CF for this use.

The tail wing and fuselage are going to be complete this week.  I mean the products and the process which I can use on any wings going forward.  The weight savings, strength and drag reduction / streamlining have me very stoked.

This is a great project which involves all of my favorite things :).
Title: Re: Print to Ride
Post by: Admin on January 13, 2023, 08:20:56 AM
I have all of the diameters correct now for a super snug fit on both fuse plugs and all wing connection rods.  This image shows all four 4mm connection rods in place on one side.  I determined that printed fuse plugs are so stiff and strong at this dimension that stock carbon rods won't add anything.  These printed plugs (pictured in fuse) will not bend or twist at all.  This fuse in the pic is 17.5 inches which will exactly equal the length of an Axis "Standard" (their longest except for the windsurfing one) when added to the extra length that occurs my front foil.  The whole Axis range is 8 inches length difference (from silly short advance to the standard) so the total range of carbon tube length in my system would be 9.5 inches to 17.5 inches to match that range (as an example).  At those lengths the flex of the tube and plugs is non-existent.  I supported the plugs only with 2x4's and bounced my entire 170 lbs on the center of the carbon tube,  It noticed no flex.  If carbon could yawn, it would have.  It is really crazy.  In the image I lightly sanded two of the 3 pieces, again just seeing how that will best be done.  This product sands beautifully so my next tests will be full assembly when the adhesives arrive.  I haven't notched the fuse yet in this image.  Oh, and the fuse, the 450 tail wing (all pieces, both plugs and all rods) weigh 7.4 ounces :).

Weird to be working from the ass forward but I needed to understand my fuse and connections to see what would be needed on the front wing.  I will start on that next week.
Title: Re: Print to Ride
Post by: PonoBill on January 13, 2023, 09:24:58 AM
Hi Bill,

I see a few things.  There is a lot of disparity between your two profiles.  You are going from 16.1% at 36.9 to 9.4% at 33.  Those are unconventional numbers at both ends for front wings.  It is going to be harder (but possible) to join there.  It will be much easier to join after the transition.  The 9.4 percent combined with the extreme contours of the main profile are going to add challenges.  If those holes are 5 mm then you are looking about 1 cm or a touch over for max thickness at 6 to 8 inches off of the root.  That is very thin.  The thinnest foil I have here is 2.4 cm at that same spot, and those carry their thickness much further out in both directions.  Also when existing foils are using a symmetrical thicker profile at the root, it is exactly matching the main profile for the top half.  The bottom is a mirror of the top.  That leaves an even top contour for the whole span.  That would also make joining (even with thicker rods) much easier)

To contour the cavities, you can use the guide sketches for your lofting as paths but 5mm tubing essentially has no usable flex.  It is going to fight you at joining for any curves.

I am not suggesting that you follow convention or modify your design to make it easy.  I dig it!  The whole point is exploration and "what if?"  That is where the fun lies.  If we want what already exists we can buy it.  There are a ton of great options. 

This PA-CF is super stiff and light and all of the carbon samples I have here are surprising as well.  I have had to completely rework what I had planned because we are dealing with so much more stiffness than I had conceived.

My Bambu has been running nonstop and I have done a silly amount of models, protos, tools, and refinements.

I have been making tools (jigs) to help me cut the notches, etc for interlocking and aligning the carbon parts with accuracy.  I also spent a few hours talking to various bonding solution mfg's and have a bunch of samples coming to test the adhesives which they are suggesting for our specific plastic to CF for this use.

The tail wing and fuselage are going to be complete this week.  I mean the products and the process which I can use on any wings going forward.  The weight savings, strength and drag reduction / streamlining have me very stoked.

This is a great project which involves all of my favorite things :).

Thanks for the suggestions. Yes, the transition in the first wing section is extreme. The symmetrical foil section is fundamentally the fuselage, and there is no reason to continue it to the first section of the wing. I can make the transition from E837 to whatever foil the first section of the wing is in the first chord shift from the center section of what I've been calling the wing root to the chord transition bit. This stuff is hard to describe, it reads like I'm discussing music theory. Since the center section is essentially the fuselage. I think I need the thickness of that chubby 837 foil to fully support the mast. These printers are amazing. Not only are the parts strong, but they're also beautiful. My Prusa and modified Ender 3s don't do prints like this. The crunchy bits on the edge of the part is from my testing. I bolted it to the leg of my workbench with a piece of angled aluminum to step on. That's all that 230 pounds did to it.

I originally envisioned carbon rods extending almost the full length of the wing. That's clearly not going to happen. I have lots of carbon rods and stuff here leftover from RC airplane and quadcopter building. Even a 5mm rod will only bend slightly. I think shorter sections to reinforce joints is a more reasonable direction. 
Title: Re: Print to Ride
Post by: Admin on January 13, 2023, 11:50:34 PM
I'm not sure how to convince a slicer to make some solid ribs, but there has to be a way. 

I am planning to do this in the file.  Basically define the shapes of the internal ribs (or voids that define the ribs, if that is how you think of it) and then cut the voids from the body.   Then just make sure that the slicer is set to print support on the plate only (so it will not fill your voids) and you have ribs to taste (which just made me hungry).  Here is a ski/snowboard vise that we produce and sell under one of our brands.  The ribbing is external on this one (and it is obviously molded for volume production)  but this is how it was done and the same applies internally.

(https://media.wiredsport.com/catalog/product/cache/5e609788430e084a92b89f88fe1f7774/v/i/vice1.png)
Title: Re: Print to Ride
Post by: Admin on January 14, 2023, 02:32:42 AM
Here is an image of the fuse guides which will print on both wings as well as the disposable collar jig (I suppose) tool I made to notch the carbon tube to match.  It just gets taped in place with painters tape and then the cuts are made with a 35000 rpm Dremel cutting disc.  Super clean and accurate notches, without splinters or fragments.  I am using my trusty Park tool for carbon steer tubes which is almost 30 years old from when we were bike shop owners.  That is still the best and easiest (30 seconds) way to cut carbon tube perfectly straight.

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/323273133_1098076210887706_5217866099752145194_n.jpg?stp=cp6_dst-jpg&_nc_cat=103&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=aX-wX9Y0Jz8AX_c2Sol&_nc_ht=scontent-sea1-1.xx&oh=00_AfA3RHmhg47tqknl_5wo3psH9ztBvqmwmPnmcBH9YR57pg&oe=63C702C9)
 
(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/325653395_701569328227457_7393485453922691072_n.jpg?stp=cp6_dst-jpg&_nc_cat=103&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=RwcurqFmKmcAX9Pehb2&_nc_ht=scontent-sea1-1.xx&oh=00_AfBLHGe78HuZenRhipYSS2Ap69a9sMe9uJPRsNB35rMcbw&oe=63C862A8)
Title: Re: Print to Ride
Post by: PonoBill on January 14, 2023, 01:09:00 PM
I'm thinking a rib structure that is printed at 100% and then the rest of the voids are printed at something around 50% or less. Doing 100% infill for the full size of a wing would be heavy and use a lot of filament. Or maybe just what I did for the blue part above which was to print the walls at about 3.3mm (I think I used 5 layers) which made both the skin of the wing and the walls of the tubing holes well reinforced. If you look closely you can see that the first and last hole walls are connected to the skin.

This is the scrunched side. I screwed the other side to my workbench with sheet metal screws, then made a step with a piece of aluminum and three long 5mm screws. I fully expected the part to break or at least tear out the screws on the bench side or rip through the holes. But nothing happened other than a little crunch on the bottom edge and maybe a little separation of the face from the wing surface toward the trailing edge, though that might just be a printing artifact. This is just PLA. I'm amazed. It seems the key to strong parts with 3D printing is not necessarily the material but the structure.
Title: Re: Print to Ride
Post by: PonoBill on January 15, 2023, 09:46:18 AM
I printed the wing root fuselage last night. seeing the physical parts illustrates refinements I need to make, but I like the progression.
Title: Re: Print to Ride
Post by: PonoBill on January 15, 2023, 12:45:46 PM
Oh, and hey admin--did you get some special support interface material to print PA-CF? The temperature range of the Bambu Labs stuff is wrong for working with PA. I've ordered some stuff from Overture that's intended for use with PA12/6 that should work. Matter Hackers has some interesting support material called Ionic, which works both as a breakaway and soluble (in water). I've ordered some but it ain't cheap. $450 for 3KG. I bought a .75kg spool for $129 to try it. Max temp is 250C, which is a bit low for PA-CF, but might be OK.

You've probably figured out by now that getting the PA-CF filament as dry as possible is critical. I'm using the ability of the Bambu printer blate to bake filament since Diane banned me from the toaster oven. I have a filament dryer box on the way, the AMS just uses a desiccant to keep humidity low--it's not a viable substitute for pre-baking.
Title: Re: Print to Ride
Post by: Admin on January 15, 2023, 02:25:43 PM
Oh, and hey admin--did you get some special support interface material to print PA-CF? The temperature range of the Bambu Labs stuff is wrong for working with PA. I've ordered some stuff from Overture that's intended for use with PA12/6 that should work. Matter Hackers has some interesting support material called Ionic, which works both as a breakaway and soluble (in water). I've ordered some but it ain't cheap. $450 for 3KG. I bought a .75kg spool for $129 to try it. Max temp is 250C, which is a bit low for PA-CF, but might be OK.

You've probably figured out by now that getting the PA-CF filament as dry as possible is critical. I'm using the ability of the Bambu printer blate to bake filament since Diane banned me from the toaster oven. I have a filament dryer box on the way, the AMS just uses a desiccant to keep humidity low--it's not a viable substitute for pre-baking.

Hiya Bill,

That is a cool direction!

I did get the green support filament  (actually kind of yellow) but I am not using it anymore.  Using the carbon for everything makes the prints go faster (a lot) and it comes off very cleanly.  I am finding it helpful to raft up 9-12 layers to get things away from the plate.  That was causing me some problems.  It is also helpful to trim a few mm of of the trailing edge in Fusion before printing.  I am sure you are on that already.  Were you getting blobs with undried filament or something else?

Working on some improved tools and a mast well right now. 
Title: Re: Print to Ride
Post by: PonoBill on January 15, 2023, 05:57:38 PM
That is a cool direction!

I did get the green support filament  (actually kind of yellow) but I am not using it anymore.  Using the carbon for everything makes the prints go faster (a lot) and it comes off very cleanly.  I am finding it helpful to raft up 9-12 layers to get things away from the plate.  That was causing me some problems.  It is also helpful to trim a few mm of the trailing edge in Fusion before printing.  I am sure you are on that already.  Were you getting blobs with undried filament or something else?

Working on some improved tools and a mast well right now.

Actually, I realized I need to modify the trailing edge this morning. I'm going to thicken it to about the width of the walls, and round it off a bit. Sanding works also, but I want the parts to be finished as much as possible right off the printer.

Yeah, switching filaments slows things down, but I get a nice, clean break and any remaining bits of support wash off quickly since the fine points dissolve almost immediately

I get blobs and rough spots with undried filament.
Title: Re: Print to Ride
Post by: Admin on January 16, 2023, 12:58:50 AM
It is a learning process for sure.  Once in place, though, it should only take an hour of work time to do a foil.  I keep seeing ways to improve each step.  V4 of my alignment tool is getting printed now.  It has two flat surfaces and some offset to combine dual sided alignment and a solid, abrasion free,  cut platform.  Not sure why that didn't occur all at once, but....

It is crazy dry in the house due to heat.  My desiccant packs are still new looking a month later.  Bora Bora has to be tough for that.  The name actually translates to "Moldy Balls".
Title: Re: Print to Ride
Post by: Admin on January 16, 2023, 01:21:52 AM
With masts now available at 2.5 lbs, there is no reason we cant have complete foil systems at under 4 lbs (Mast, foil, fuse, tail and all hardware). 
Title: Re: Print to Ride
Post by: PonoBill on January 16, 2023, 02:50:47 PM
What masts weigh 2.5 lbs??
Title: Re: Print to Ride
Post by: Admin on January 16, 2023, 03:13:54 PM
What masts weigh 2.5 lbs??

NoLimitz.  I am doing the Takuma adapter next.  :)

https://www.nolimitz.com/foilmasts
Title: Re: Print to Ride
Post by: PonoBill on January 16, 2023, 03:21:27 PM
Some refinements on the original fuselage ideas. Narrower, a little more refined shape, and the trailing edges of the airfoils are rounded. Can you tell I'm still struggling with fucking lofts and splines? I suspect the culprit might be the dat-to-spline tool. If I don't get it hammered down soon I'll probably start tracing the airfoils, and wouldn't that just suck. Anyway, the mast-to-fuselage tube connection is bomber and I can't twist it even with just hot glue. The trick is the little divot on the male part of the plug. It creates a wedge of glue that resists twisting--same thing we did with Kenalu paddles. Only this shaft winds up being glued both inside and outside since it inserts into the female socket up to the mast. If I really wanted to get crazy I could V-notch the end of the tube and use the mast as a key. All this stuff reads like a porn script. The mast cutout for an axis aluminum mast fits tightly but well. A little persuasion with a mallet and Bob's yer uncle. I haven't figured out how to do a countersink on a curved surface yet. It's obvious that the hole tool understands the issue, I just haven't figured out what it's asking for.
Title: Re: Print to Ride
Post by: PonoBill on January 16, 2023, 04:27:13 PM
bottom. The live piece is even prettier--or it was until I broke it. If I jump up and down on my goofy test jig you can indeed break one. It was 20% infill and a 3-layer wall so that's not too surprising.
Title: Re: Print to Ride
Post by: PonoBill on January 16, 2023, 04:31:32 PM
The NoLimitz masts have always been tempting. No adapter is necessary if we go with my fuselage approach. Why add a bag on the box. Bare nekkid.
Title: Re: Print to Ride
Post by: Admin on January 16, 2023, 11:33:28 PM
bottom. The live piece is even prettier--or it was until I broke it. If I jump up and down on my goofy test jig you can indeed break one. It was 20% infill and a 3-layer wall so that's not too surprising.

Hiya Bill.  Are you still printing in Blue PLA?  If so switch to solid carbon (PA-CF) for the center section with zero infill and test again.  Nothing will break, even press fit/no glue.  That is also important because the materials retract differently and you will need to redo your tolerances when you switch.  You will need some kind of fuse key on both ends to get/keep the rear wing angle perfect.  glue notches or perf holes are a great idea.  I want the root component ready to accept anything we throw at it.  Any mast head, adaptor or bare mast should fit with a simple extrusion.  Mast attachments (and bare masts) are all really basic shapes with very little dimension variation and once the universal head block is done we can use any or all.
Title: Re: Print to Ride
Post by: PonoBill on January 17, 2023, 12:34:01 AM
Yeah, I think you're right. This one is PA-CF. The cutaway for the mast is too tight. I couldn't get it inserted even with the BBFH (big, big fucking hammer).

I'll probably take the layer height down to .16mm to get a better surface finish. Easy enough to sand it smooth, but I'd like it to be smoother right out of the printer. If I were using a single filament I'd probably do adaptive layering, but I like the yellow support filament.
Title: Re: Print to Ride
Post by: Admin on January 17, 2023, 01:16:20 PM
Yeah, I think you're right. This one is PA-CF. The cutaway for the mast is too tight. I couldn't get it inserted even with the BBFH (big, big fucking hammer).

I'll probably take the layer height down to .16mm to get a better surface finish. Easy enough to sand it smooth, but I'd like it to be smoother right out of the printer. If I were using a single filament I'd probably do adaptive layering, but I like the yellow support filament.

Looks cool!  I have been doing a bunch of smaller mast well models and I finished the (uncut or rodded) Alien wing this morning.  Lots of stuff to test, break and adjust.

How much material below the base of the mast well base will be needed?  I matched Axis at 6.5 mm for now.

How much non tapered thickness surrounding the exposed areas of well?  I went with 6.5 mm again and mostly that rolls off into more substance.

How deep does the fuse plug (even if molded) need to penetrate into the wing.  I went with 60 mm. 

There are a million choices, and I can be an eternal editor.  At some point I gotta bring it in for a landing. 
Title: Re: Print to Ride
Post by: PonoBill on January 17, 2023, 03:47:34 PM
I have questions:

Where did you get the carbon mast tube? I can't find 19mm OD, 15 ID anywhere. The 19mm sounds suspicious. Some kind of sports thingy?

This PA-CF shrinks dimensionally quite a bit. Have you settled on a percentage? I increased the size of the mast cutout by offsetting the outer edge of the mast cutting tool by 1mm and decreasing the size of the inner plug by 1mm. It's not quite enough. I'd like a tight fit but I still can't hammer it into place.

I also went too far on scaling down the chord where the mast attaches. I want the front of the shroud to start at about 33 to 50% of the chord. The latest version is more like 75%. I guess that's not really a question.

This is though: Fusion 360 continues to seem random. Actions that worked an hour ago suddenly don't work. I thought perhaps I needed to be more careful selecting what construction plane I'm working on, but nope. Any words of wisdom?

You said you aren't using breakaway support material anymore. I have a tough enough time removing supports with the breakaway stuff. How are you making that work?

Here are my answers to your questions though, or at least what I'm doing right now:

q: How much material below the base of the mast well base will be needed?  I matched Axis at 6.5 mm for now.

a: I'm at 14mm.

q: How much non-tapered thickness surrounds the exposed areas of well?  I went with 6.5 mm again and mostly that rolls off into more substance.

a: Mine varies from 10mm at the back to 5mm at the front.

q: How deep does the fuse plug (even if molded) need to penetrate into the wing.  I went with 60 mm. 

a: What? my part is only 32mm deep. I'm at 14mm deep in the back and 12mm in the front except at the tip of the leading edge where it's just 7mm.

The breakaway stuff is very sensitive to the interior temperature. I've had it print perfectly, but last night I forgot to close the door and got this:

Title: Re: Print to Ride
Post by: Admin on January 18, 2023, 02:43:21 AM
I have questions:

Where did you get the carbon mast tube? I can't find 19mm OD, 15 ID anywhere. The 19mm sounds suspicious. Some kind of sports thingy?

This PA-CF shrinks dimensionally quite a bit. Have you settled on a percentage? I increased the size of the mast cutout by offsetting the outer edge of the mast cutting tool by 1mm and decreasing the size of the inner plug by 1mm. It's not quite enough. I'd like a tight fit but I still can't hammer it into place.

I also went too far on scaling down the chord where the mast attaches. I want the front of the shroud to start at about 33 to 50% of the chord. The latest version is more like 75%. I guess that's not really a question.

This is though: Fusion 360 continues to seem random. Actions that worked an hour ago suddenly don't work. I thought perhaps I needed to be more careful selecting what construction plane I'm working on, but nope. Any words of wisdom?

You said you aren't using breakaway support material anymore. I have a tough enough time removing supports with the breakaway stuff. How are you making that work?

Here are my answers to your questions though, or at least what I'm doing right now:

q: How much material below the base of the mast well base will be needed?  I matched Axis at 6.5 mm for now.

a: I'm at 14mm.

q: How much non-tapered thickness surrounds the exposed areas of well?  I went with 6.5 mm again and mostly that rolls off into more substance.

a: Mine varies from 10mm at the back to 5mm at the front.

q: How deep does the fuse plug (even if molded) need to penetrate into the wing.  I went with 60 mm. 

a: What? my part is only 32mm deep. I'm at 14mm deep in the back and 12mm in the front except at the tip of the leading edge where it's just 7mm.

The breakaway stuff is very sensitive to the interior temperature. I've had it print perfectly, but last night I forgot to close the door and got this:

This is the best tube.  I ordered a few types including from the premium vendors and its not even close.  It is actually one of the nicest finished carbon products I have seen.  https://www.amazon.com/dp/B08J8FYJ7T?smid=ARU89Z0RN1J44&ref_=chk_typ_imgToDp&th=1.  I have two tubes here and just ordered two more.  My caliper picks up zero variation in ID or OD on either tube, either end, or at my cuts and it is super accurate and calibrated.  One of the "premium" ones was as consistent as a zucchini.

I don't think it is just shrinkage on the PA-CF.  I think a part of it is high nozzle temp and gravity in that instance before cooling.  The same tube horizontally will have the tiniest bit of sag while the vertical version is 100% true to spec.  It also depends on if you are using support inside the holes and drilling.  That is not a bad way to go although skipping it is nice.  There is a hole adjust feature in Bambu studio that allows you to adjust there.  I would avoid that.  It is hard to control and its a major time suck.  My 4 mm holes are 4.12 in Fusion and that works great at my print angles.  I did a test block for hole sizes and then realized that a modified version  would also make a great rod cutting tool.  I have that set up so I can straight cut 5 rods to length at once with the Dremel and the cuts are square.

Fusion is F'in amazing but quirky as hell.  Mostly because fiddly AI interference.  It tries to assume contextually what you want from a step.  Hate it and you cant entirely disable it, I asked.  The big one is selection.  If you select from your whole project (everything visible) and for instance use the move tool, it may auto populate "bodies" when you need "sketch", even though the sketched item is selected, and it wont let you move your sketch.  Easy to fix if you see it but until you do...  If you ever are having real trouble make only the part you are working on visible, select that and then move on.  Also, zooming way in is critical when making attachments. 

The carbon supports break right off.  Raft it up 10-12 layers to get away from the heat of the plate.  That helps everything a lot.
Title: Re: Print to Ride
Post by: PonoBill on January 18, 2023, 10:55:32 AM
You must have run through a ton of filament to come up with that. Rafts have only been available in the newest release of the Bambu slicer. I looked for them with my original Kickstarter printer and they weren't there, even though the slicer is based on a lot of Prusa Slicer code and apparently a splash of Cura. Apparently, they added it back in release 1.4.0.18.

I knew there was some kind of malevolent being in Fusion 360 that's been fucking with me, but I didn't realize it was AI. Figures. Selection of joined bodies seems to be completely random in how many elements are selected. Yeah, hiding stuff is my friend. I tried to make some holes by shoving a set of spaced cylinders through the wingroot but when I did Combine to make the cut I could select the wingroot but not the cylinders. Gaaah. I tried making the holes by extruding circles through the wingroot, which usually cuts nicely--I've done it a hundred times--and it didn't include cut in the selection, just join. I finally had to use the hole tool, which is always a bit bitchy to locate exactly where you want. I had to draw centerpoint circles, locate the hole on the centerpoint, and then do the cut. Yeah, the AI is saving me a lot of time.

Mr. Bambu has been printing perfectly--until last night when my print decided to detach from the plate about halfway through. Since then the printing has been progressively more gooky (technical term) so I pulled the extruder apart and cleaned the nozzle. I knocked a plug out that looked like CF minus the PA. I assumed the CF stands were microscopically short. They aren't. They look to be about 1/32" long, which is fairly long for something with a diameter about half that of human hair. I think it's OK now, the raft looks OK. The first layer was a bit skanky but the second looks better.
Title: Re: Print to Ride
Post by: Admin on January 18, 2023, 02:01:37 PM
I was running blissfully for a ton of prints until yesterday when a long print started air printing right at the end.  Shit.  Took apart everything but the extruder, cleaned it out using that hot allen key trick and then the needle, got it running again for short print and then another air print today.  Shit.  I think the nozzle is just done.  I ordered three hotends complete so I can just plug and go.  That cleaning process is not worth 30 bucks.  Which nozzle size are you using?
Title: Re: Print to Ride
Post by: PonoBill on January 18, 2023, 05:13:30 PM
Check the extruder drive wheels as well. You need to print the tool to take the big red gear off the extruder body: https://wiki.bambulab.com/x1/troubleshooting/extruder-clog/gear_removal_tool.stl

Even just a little gook around the drive wheels can cause slipping. Here's how to clean it up: https://wiki.bambulab.com/en/x1/troubleshooting/extruder-clog

I'm using .4 but I just ordered a .6. I hear that's better for filament with anything added.
Title: Re: Print to Ride
Post by: Admin on January 19, 2023, 01:16:47 AM
I'm using .4 but I just ordered a .6. I hear that's better for filament with anything added.

Pretty sure this is my issue.  I have been breaking all the rules.  .4 nozzle, full speed, lots of infill, long prints, always less than the suggested layers of .20, etc.

Works great until it doesn't.   

I am going to need a print farm and some interns.  Welcome to your summer position at Gorge Foil Works.  Your code name is Thermal Paste.  Lets begin training by hand sanding these 17 foils and please keep an ear open for printer yelps. 
Title: Re: Print to Ride
Post by: Admin on January 19, 2023, 09:23:32 AM
Disassembled the extruder but that was all looking good.  I ordered three extruders so I have them on hand.  This rebuilding will get old fast.  I hate being dead in the water :).
Title: Re: Print to Ride
Post by: PonoBill on January 19, 2023, 10:00:21 AM
Well, we've got a start on the farm, between us we have three Bambu printers, two with AMS. I'll probably add AMS to my original one. And I have three Creality Ender3s with various levels of modification and sophistication, one Prusa, one semi-no-name printer that's a bit obsolete, made by a manufacturer that left the biz, and one SLA resin printer--a Form One. All of these things can be set up to run remotely in various unmanageable ways, The three Bambus are easy, each printer can be run with the cloud printer interface--they don't have to be just on the local network. The Prusa has various remote options, and I have a primitive AMS for it that I more or less abandoned but could give another shot at. I plan to bring the Bambu back to HR when I leave Moldy Balls. I might bring the Prusa and AMS as well.

Incidentally, Adafuit has a useful and short article on scaling and calibrating printers: https://us10.campaign-archive.com/?e=8dce67b92e&u=86903b65c84293425f40fa9a5&id=637000bee2

I have a geek crush on Limor Fried, who founded Adafruit. She's a wizard, and her company is a huge source of DIY tech and information.
Title: Re: Print to Ride
Post by: PonoBill on January 19, 2023, 10:10:33 AM
Oh, and I tried your trick with the raft and using PA-CF for support. We must have different ideas about "easily removable". I spent half an hour with a knife getting the support off. And I can tell you that printing larger things with a raft and PA-CF support will temporarily warp the build plate and lift it off the magnets. I watched my print bounce up and down last night--not pretty.

On the plus side I did a PLA test print of the refined fuselage. Success, and it looks right as far as mast vs. wing position. Is this pretty or what? Note that I can easily add a fourth carbon rod hole and still miss the mast. The mast/shroud interface is a shade loose with PLA, but might be better with PA-CF. I did 50% infill since it's just a prototype to refine, but it's crazy strong.

I need to add a fillet to the wing root/shroud interface. It should be easy since I've combined the bodies but the Fusion 360 demon doesn't believe that the interface line should be selectable to fillet.
Title: Re: Print to Ride
Post by: PonoBill on January 19, 2023, 11:47:09 AM
Through sheer dumb persistence, I managed to wrestle the demon into a draw and add a few fillets. Not exactly as I wanted them, but close.

Title: Re: Print to Ride
Post by: Admin on January 19, 2023, 02:01:56 PM
This is where I am.  The system aspect of it is mostly together now, I see how it should work and a number of options of how I can build it.  My nozzle is ruined, so I am waiting on printer parts.  The image shows  my Axis well (Ok, 7/8 of it because the printer cut out), it is an awesome fit with no gaps.  Also a cut carbon tube with the updated notching tools on the ends.  Those work great.  Also pictured is the sliver of my front wing which printed (again before cutting out).  It has 30% infill although I will likely do the center 4 inches as solid.  I am shocked how stiff this sliver is.
Title: Re: Print to Ride
Post by: Admin on January 21, 2023, 12:35:37 AM
Hi Bill,

Just saw this video.  This could be used to add solid ribs or sections from inside Studio.

https://www.youtube.com/watch?v=Pl_FD7LBOQM
Title: Re: Print to Ride
Post by: Admin on January 22, 2023, 10:31:37 AM
Here is the print from Yesterday.  Very stoked with everything except that I cannot finish a long print without the printer cutting out.  Brand new nozzle and extruder.  I think a .6 nozzle is going to be the next step.  This is also a solid part so I may reduce it a bit and see if that gets it done.  It is overkill as is, so a bit of reduction is in order anyways.  The bars/hole are printed 15 mm bars.  two steps forward...
Title: Re: Print to Ride
Post by: PonoBill on January 22, 2023, 11:52:59 PM
I have officially mastered both lofting and printer calibration--at least at the Moldy Balls level. I'm enthusiastic as hell about my newfound knowledge though I'm sure I'm going to start breaking shit in every direction.

In other news, the surf is fucking huge. I think most of the serious big-wave dudes are at the Eddie, but Peahi is breaking at record heights. When the surf is making it over the island at the tip of our bay it means Peahi is breaking. I've never seen it like this before--It looks and sounds like nuclear explosions on the west end. That's a little over a mile from my patio. The rocks are rolling around on the beach below the house. It's like a bowling alley without skanky shoes.
Title: Re: Print to Ride
Post by: Admin on January 24, 2023, 01:45:44 AM
I have officially mastered both lofting and printer calibration--at least at the Moldy Balls level. I'm enthusiastic as hell about my newfound knowledge though I'm sure I'm going to start breaking shit in every direction.

In other news, the surf is fucking huge. I think most of the serious big-wave dudes are at the Eddie, but Peahi is breaking at record heights. When the surf is making it over the island at the tip of our bay it means Peahi is breaking. I've never seen it like this before--It looks and sounds like nuclear explosions on the west end. That's a little over a mile from my patio. The rocks are rolling around on the beach below the house. It's like a bowling alley without skanky shoes.

Master of the loft.  I am picturing drum circle Babcock with an old school bong, surrounded by vaping hiplets, erupting in plausibly Lakota outbursts for full affect.   
Title: Re: Print to Ride
Post by: PonoBill on January 24, 2023, 10:03:08 AM
Old School Bong--could be a good name for a rock group of geezers. I had one about 3' X 6" made from a section of bamboo I cut down on a golf course in Long Beach. I punched out the center web and made a pipe bowl in pottery class (see, pottery class is good for something). Best bong ever.

Anyway, here's the latest fuselage section done in PC (polycarbonate). I forgot to have the printer iron the top. This would all be easier for someone who never forgets where he left his pants. PA-CF is intrinsically prettier. Still needs a little refinement. Yesterday was a "two steps back" day because the tool I made for cutting the mast hole decided not to work. I'd done a few tweaks to the sketch dimensions, expecting to need to extrude it into a mast and bolt-hole cutters but it looked like it was already done as soon as I clicked "extrude". I think it was just a buffer ghost, so the cutter worked randomly. Took me forever to work out the issue.

On the positive side, I am the master of loft and rails, a title I plan to add to my formal name:
William Babcock Jr. MaLR BFD LMnoQ

Title: Re: Print to Ride
Post by: PonoBill on January 24, 2023, 12:21:46 PM
Mast and bolt hole cutter, along with a smoosher tool to take the sharp edge off the mast hole without lopping off the mast inner plug. And the modified and smooshed wing root with fillets and geegaws

Title: Re: Print to Ride
Post by: PonoBill on January 25, 2023, 06:32:49 PM
I got about 40 percent through a print test last night and my .4 nozzle clogged and started printing nothing. I decided to install one of the .6mm hotends I recently received. Got it all reassembled and the filament wouldn't load. So I took the entire extruder out and found a piece of cut filament lodged sideways. So that was fun. But I have to say that .6 printing looks very promising. I'm not sure why, but the print looks more precise and the goofy Support G stuff isn't stringing like it usually does. So I got that going for me.

I finally got my 1200mm X 19mm OD, 15mm ID tube. It's a nice-looking part, hyper-stiff, though it's a tiny bit bowed. I rolled it on a marble slab and it's roughly 1/16th bowed. It won't matter much in fuselage length.

The bad news is that it's generated another round of re-designing the wing root. I don't think the 15mm plug is robust enough on its own. I think it's important that it slides into the shroud for some distance, and I don't want a step in the transition--a streamlined connection. That means the insertion length needs to be even deeper since a streamlined connection is intrinsically thin. Obviously gluing all this together will help brace the flimsy bits, but I want the connection to be as strong as possible. Printing these parts in PLA with infill made it easy to see (qualitatively) where the weak spots are going to be. The plug is about the weakest spot.
Title: Re: Print to Ride
Post by: Admin on January 26, 2023, 03:00:07 AM
I got about 40 percent through a print test last night and my .4 nozzle clogged and started printing nothing. I decided to install one of the .6mm hotends I recently received. Got it all reassembled and the filament wouldn't load. So I took the entire extruder out and found a piece of cut filament lodged sideways. So that was fun. But I have to say that .6 printing looks very promising. I'm not sure why, but the print looks more precise and the goofy Support G stuff isn't stringing like it usually does. So I got that going for me.

I finally got my 1200mm X 19mm OD, 15mm ID tube. It's a nice-looking part, hyper-stiff, though it's a tiny bit bowed. I rolled it on a marble slab and it's roughly 1/16th bowed. It won't matter much in fuselage length.

The bad news is that it's generated another round of re-designing the wing root. I don't think the 15mm plug is robust enough on its own. I think it's important that it slides into the shroud for some distance, and I don't want a step in the transition--a streamlined connection. That means the insertion length needs to be even deeper since a streamlined connection is intrinsically thin. Obviously gluing all this together will help brace the flimsy bits, but I want the connection to be as strong as possible. Printing these parts in PLA with infill made it easy to see (qualitatively) where the weak spots are going to be. The plug is about the weakest spot.

I have the .6 nozzles now as well.  What layer heights have you tried?  Air printing (in my case) means a stuffed nozzle.  If the nozzle gets plugged, then the extruder jams as well.  You can clean it all and get it working again but the trust is gone and once the parts have failed they seem to keep failing (on long prints). 

Your part is small still so likely under 8 hours?  My part is a lot bigger than yours. Had to be said.  It is the really long print times that are causing the most issue.

The 15 mm plugs are super strong.  You can stand on those with full weight and bounce.  They will need to be deeply rooted.  I mentioned this above but I have left a lot of meat between the mast well and the fuse plug.  At least at first I want the whole hub/console to be bomber. 

You should contact the carbon tube guys.  I have 4 tubes here now with no discernable bow.  Even a little bow is going to throw your incidence, your righty/lefty or both.   
Title: Re: Print to Ride
Post by: PonoBill on January 26, 2023, 09:25:15 AM
So far I'm not thrilled with the .6mm nozzles. Lots of failed prints lately. I've been using default setting for .6mm with the exception of a little rafting and thicker walls. I didn't screw with recommended layer height. I'm getting a lot of blobs, even with PLA.

The bowing of the carbon tube is pretty small. I figured I'd use it like a fishing rod blank where you find the direction it droops the most and mark that as the top. Incidence can be measured and adjusted for as long as the droop is slight, righty-lefty not so much.

I've been working on this stuff a lot since there is absolutely no fucking wind. The surfers and the golfers are happy. Maybe I should take up golf--just shoot me now.
Title: Re: Print to Ride
Post by: Admin on January 26, 2023, 02:22:36 PM
So far I'm not thrilled with the .6mm nozzles. Lots of failed prints lately. I've been using default setting for .6mm with the exception of a little rafting and thicker walls. I didn't screw with recommended layer height. I'm getting a lot of blobs, even with PLA.


For the PACF (now they are calling it PAHT-CF) they are suggesting the .6 nozzle with a .2 layer height.   The default layer height when you switch to the .6 nozzle is (oddly) .3 so I would change that for sure.  Smaller may work as well, but..   I think I finally have settings that will work but I will let you know in a bit.  Long prints with carbon have been driving me nuts.  This whole concept hinges on being able to print large carbon parts so this needs to work.   More soon...
Title: Re: Print to Ride
Post by: PonoBill on January 26, 2023, 08:38:04 PM
Yeah, I tweaked the settings a bit, and a lower layer height cleaned the prints up a lot and cut back on the blobs. I went back to .4 just because. And everything is printing nicely. I think .6 is a definite requirement for filament with stuff in it, but I was a bit sick of twiddling. I have some more spools of PA-CF on the way. I'm printing my latest design and a wing section in PETG just to see how stuff fits together. The shrouded peg tail boom connection is bomber. I glued one up with epoxy with the body in straight polycarbonate, and I can't flex it, never mind breaking it.
Title: Re: Print to Ride
Post by: PonoBill on January 27, 2023, 01:40:29 PM
So this is wild, and has implications for all kinds of things, including the Faux Drive I've built but have had endless problems keeping a propellor together for. I'd buy a metal prop from Foil Drive if I could, but they only sell them to customers. I think this prop would be a lot stronger as a 3d print and more efficient and safer if I get tangled up in it. The overall idea might play well in a 3D-printed wing--no tip vortices because no tips. Might not be worth the extra work, and I certainly wouldn't want to build one any other way--I can't imagine the work required to mold one. There was a hydrofoil built this way but made with conventional carbon fiber construction.

https://www.youtube.com/watch?v=fO862lWuBdE
Title: Re: Print to Ride
Post by: PonoBill on January 28, 2023, 01:27:19 PM
Nice of Sharrow to provide drawings. Maybe I could get them to send me a .f3d file. Mmmm probably not, they've patented the shit out of this thing. From the looks of the drawings, which I grabbed off one of the videos, they made this one to run from an electric motor or a very small outboard. Big outboards connect with a spline, not a shaft and shear pin.
Title: Re: Print to Ride
Post by: Admin on January 29, 2023, 02:34:18 PM
So happy to have that unexpected detour in the rearview.  That was driving me nuts.  I finally have printer config and slicer settings that will allow for large (and long duration) solid carbon parts without jamming. This hub is really critical because it will manage (almost) all of the loads and I want it to be rock solid - and now it is.  All of the other parts will have much shorter print times.  I have the next wing section printing now.  This printer is named the X1 Carbon so you would think it would come ready to print carbon.  To some degree it is, but really only for relatively small prints.  It will definitely do larger parts but it does take accessories and a lot of fiddling.
Title: The king is dead...
Post by: PonoBill on January 29, 2023, 06:14:54 PM
So much for having mastered lofts and rails. I'm going insane trying to loft wings with airfoils and splined rails. The dreaded "rail does not connect to all profiles" with one end of the rail floating in the air. I've tried coincident constraints, projecting an interface, and construction lines through the middle. All the tricks work perfectly with any other shape but don't work with the dat-to-spline airfoils. I've even tried tracing them.

On top of that my last four prints failed, with more or less the same problem you described, which is odd because I have several PA-CF prints with even larger areas, but I'm getting lifting and even distortion of the print plate (never saw that before). So what did you find?
Title: Re: Print to Ride
Post by: PonoBill on January 29, 2023, 07:02:16 PM
A nice print by the way. What size are those rod holes? I'm using 5mm, those look more like 8mm.
Title: Re: The king is dead...
Post by: Admin on January 30, 2023, 04:17:54 AM
So much for having mastered lofts and rails. I'm going insane trying to loft wings with airfoils and splined rails. The dreaded "rail does not connect to all profiles" with one end of the rail floating in the air. I've tried coincident constraints, projecting an interface, and construction lines through the middle. All the tricks work perfectly with any other shape but don't work with the dat-to-spline airfoils. I've even tried tracing them.

On top of that my last four prints failed, with more or less the same problem you described, which is odd because I have several PA-CF prints with even larger areas, but I'm getting lifting and even distortion of the print plate (never saw that before). So what did you find?

Hi Bill, a few things.  How many profiles are you linking?  Are you doing your rails all on a single sketch or on multiple sketches?  What plane are you sketching your rails on?  No profile movement of any kind before doing your rails and lofting, right? I am sure you are manually closing the profile ends (trailing edge), but that is also mandatory.   Which points are you choosing as attachment points on the profiles.  Are you super zoomed in to be sure you are attaching top the right point (very easy to miss).  Same points used on all profiles, right?  I hope am am hitting all of the points but I may have missed some.  This part is super fidgety.  I for the life of me do not know why Fusion is so specific with these profiles.  Lofting anything else is super easy even with really complex shapes and a lot of rails.

I haven't seen any lifting of the plate yet and no warping.  Are you using the engineering plate?  The one with no tape, just the bare plate?  That is the only way to go for Carbon.  You may want to cool your late a little.  I did burn the surface on one of the plates early on  (the other side was still fine after peeling off that BS tape).  That was when I was printing with no loft.  That was sucking anyways because the base of the print mushrooms a bit and gets this melty glaze.  Rafting fixes all of that. 


Title: Re: Print to Ride
Post by: Admin on January 30, 2023, 04:40:13 AM
A nice print by the way. What size are those rod holes? I'm using 5mm, those look more like 8mm.

They are 15 mm :).  I realized after jumping on my printed rods, "why am using anything else?"  This way we can create cavities which act as ribs and the separately printed rods can link and add massive reinforcement at custom sizes.  On the next wing section they are 15 mm on one side and 12 mm on the other, although of course you could use multiple sizes at one joint.  It is amazing how this stuff evolves as you get into the process.
Title: Re: Print to Ride
Post by: PonoBill on January 30, 2023, 09:08:00 AM
How straight are your printed rods? I get a substantial amount to creep and warp on the ones I've printed. I assume that even pultruded carbon rods are stronger and stiffer than anything we can print, and it's nice to have lengths longer than 230mm available. Not to mention the printing time.

Yeah, I can rail to complex shapes and with weird dimensions off the drawing plane with ease. But as soon as I plop an airfoil down everything goes to shit. Even tracing the shape with a single spline (or two, for that matter) leaves the rails hanging in space. The closest I've gotten is by centering the foil along the plane and using project>interface, but that only works if you want a straight wing, not one with an anhedral. Sometimes the foil shapes are not even clickable--even for constraints. I'm going back to square one and learning the software from first principles. That's going well and I'm progressing rapidly--at everything but the stuff I actually want to do. I can design a parametric desk and animate the assembly like a pro, but I don't want to do any fucking woodworking.

I'll try your list of "things I might be fucking up" and report back. I talked to Raaphorst about it yesterday and he said sometimes he has to simplify the shapes a bit by boxing the ends. Tried that, no dice. It might just be AI payback for crowing that I got this shit mastered.

I'm going to go beat up the dog a bit. It's safer than grumping at Diane.
Title: Re: Print to Ride
Post by: PonoBill on January 30, 2023, 04:05:07 PM
Wait, What? 15mm?? How thick is your wing going to be. I'm basing mine on the 999 ART. It's not 15mm thick.
Title: Re: Print to Ride
Post by: PonoBill on January 30, 2023, 09:34:29 PM
I'm McLovin' this innie/outie plug and shroud joint. Mega strong, and slick. I used a bit of JB weld to stick the carbon tube into the PA-CF body. That shit is hard to sand.

Going to .2mm layer height with the .6mm extruder is nice. Rafting it up a bit (6 layers) and getting the support right without using support filament solved the rest. Oh, and I dropped the nozzle and bed temp to 2 degrees above the minimum. I'm going to try annealing these in sand in the oven. I tried it with a little PLA hook and it's crazy strong. No infill, heating parts with infill to the crystallization temp makes them warp like mad. It adds two hours to the production time, but it's on its own for most of the time and I can bake bread at the same time. The bread tastes a little funny...
Title: Re: Print to Ride
Post by: Admin on February 01, 2023, 05:51:25 AM
Wait, What? 15mm?? How thick is your wing going to be. I'm basing mine on the 999 ART. It's not 15mm thick.

Hiya Bill,

Check that measurement.  Axis uses 16 mm front screws on the ART's that don't poke though so those wings are likely 20-21 mm thick ? for the width of the fuse head at least.  The Axis Red fuse head itself is just under 2.4 cm thick and we know that there is an extra .6 under that for screw attachment depth.  Their heads are 2.5 inches wide.  With that we know that every foil that fits an Axis red fuse is a minimum of 3 cm thickness for about 3 inches of span at the root.  I am thinner than they are at the max dimension and then I drop off quickly from there.  Also, I have no symmetrical section, so my entire span is lift producing (Bernoulli style). Where we are adding max drag we should get the max lift benefit :)
Title: Re: Print to Ride
Post by: PonoBill on February 01, 2023, 01:04:51 PM
Well, math is cool and all that, but I just directly measured my ART999 and it's 16.5mm thick at max. So I was wrong, it IS more than 15mm thick, but not much thicker.

My wing root section starts off with a symmetrical foil but I've slimmed that down to just the width of the shroud, about 32 mm, and then it transitions to an E818 foil which is decidedly Bernoulli-ish. The symmetrical section gets down to 12mm thick (driven by the chord and the foil profile) about 20mm from the start of the transition. One of the reasons I chose the 818 profile is that it has a similar thickness to the ART999 for the same chord.
Title: Re: Print to Ride
Post by: Admin on February 03, 2023, 01:08:42 AM
Hi Bill,

What schedules and temps have you tried so far for annealing?  I am finding stuff all across the map.  All are very long processes and nothing specific for our PA-CF yet.  Bambu says on their spec that they are annealing for their tests but they give no specifics, only a drying temp.  They give us a crystallization temp of 140 C/284 F so we have that.  I have plenty of parts here to test in the oven and can set any schedule with unlimited timed steps, so the time is really not a factor but...

https://www.boedeker.com/Technical-Resources/Technical-Library/Plastic-Annealing-Guidelines
https://www.plasticsintl.com/media/wysiwyg/Nylon___Reinforced_Nylon_Annealing.pdf
Title: Re: Print to Ride
Post by: finbox on February 03, 2023, 08:14:56 AM
I worked in a factory where we had some plastic parts ( I think some type of nylon, injection molded)- We had a post treatment of boiling them in water for a few hours. That added ductility or fracture toughness to the parts.
Title: Re: Print to Ride
Post by: PonoBill on February 03, 2023, 09:32:24 AM
Boiling in water is kind of a standard method, but the temperature is a little low for nylon. The intent is to hold the part above the crystallization temperature and the gold standard is to encase the parts in plaster while you bake them. Way too much work. I'm stuffing them into sand and baking at 350F for two hours starting with a cold oven. In theory, I could go a little higher, ramp the temperature more slowly, and hold the temp longer, in practice, it works pretty well. The edges get a little blurry at 350. I'm going to try 300 and see if that works better.

In the general 3D printing community it looks like people are using lower temperatures for PA--lower temps held for a long time will actually help for heat resistance and strengthen the part a little bit, but not as much as exceeding the temperature of crystallization. I suspect they use lower temps because they use sparse infill and don't want their parts getting tweaked and collapsing. Sand helps to a surprising degree with minimizing distortion, and solid parts don't collapse.

I suspect there is more going on with 3D print annealing than just molecules getting aligned. The large increase in strength from aligning layers parallel to the direction of forces applied makes it clear that the layers are not completely bonded. Ideally, we'd probably remelt the part and let the layers flow together. Practically, this would result in a puddle of plastic. I suspect there is some improvement in layer bonds at temperatures that don't melt the plastic but encourage migration. For that matter, temperatures are never evenly distributed so microscopically hotter areas might melt and flow.

Whatever the case, I'm seeing a substantial improvement in strength using my primitive and inaccurate testing methods.
Title: Re: Print to Ride
Post by: PonoBill on February 03, 2023, 09:37:30 AM
So this only took five tries to get all the dimensions right (particularly bolt locations). I want to test my stabilizer designs on an axis mast and front foil before doing a lot of work building them the way I think they should be designed. So I made an adapter, which will also work for adapting KD tails to Axis and makes a good basis for making shims for axis tails.

Of course, I'm not going to really print these in PLA, and switching to PA-CF is probably going to screw up the bolt-hole locations, but printing in cheap and easy PLA first feels comfy to me. I still struggle a little with PA-CF, the print settings to get nice parts are ridiculously critical.

Title: Re: Print to Ride
Post by: Admin on February 04, 2023, 01:18:45 AM
Boiling in water is kind of a standard method, but the temperature is a little low for nylon. The intent is to hold the part above the crystallization temperature and the gold standard is to encase the parts in plaster while you bake them. Way too much work. I'm stuffing them into sand and baking at 350F for two hours starting with a cold oven. In theory, I could go a little higher, ramp the temperature more slowly, and hold the temp longer, in practice, it works pretty well. The edges get a little blurry at 350. I'm going to try 300 and see if that works better.

In the general 3D printing community it looks like people are using lower temperatures for PA--lower temps held for a long time will actually help for heat resistance and strengthen the part a little bit, but not as much as exceeding the temperature of crystallization. I suspect they use lower temps because they use sparse infill and don't want their parts getting tweaked and collapsing. Sand helps to a surprising degree with minimizing distortion, and solid parts don't collapse.

I suspect there is more going on with 3D print annealing than just molecules getting aligned. The large increase in strength from aligning layers parallel to the direction of forces applied makes it clear that the layers are not completely bonded. Ideally, we'd probably remelt the part and let the layers flow together. Practically, this would result in a puddle of plastic. I suspect there is some improvement in layer bonds at temperatures that don't melt the plastic but encourage migration. For that matter, temperatures are never evenly distributed so microscopically hotter areas might melt and flow.

Whatever the case, I'm seeing a substantial improvement in strength using my primitive and inaccurate testing methods.

I opened a (new) ticket with Bambu and asked on their forum.  It is their product and they need to tell us.  Of course, I completely get why they do not want to, but...

PS, sweet on the adapter!
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