Author Topic: Print to Ride  (Read 20933 times)

PonoBill

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Re: Print to Ride
« Reply #30 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).
« Last Edit: January 02, 2023, 08:14:33 AM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PonoBill

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Re: Print to Ride
« Reply #31 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.
« Last Edit: January 02, 2023, 09:09:48 AM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PonoBill

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Re: Print to Ride
« Reply #32 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.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

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Re: Print to Ride
« Reply #33 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



« Last Edit: January 02, 2023, 11:52:51 AM by Admin »

PonoBill

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Re: Print to Ride
« Reply #34 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.
« Last Edit: January 02, 2023, 05:08:59 PM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PonoBill

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Re: Print to Ride
« Reply #35 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.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PonoBill

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Re: Print to Ride
« Reply #36 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.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

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Re: Print to Ride
« Reply #37 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.



« Last Edit: January 03, 2023, 01:12:02 AM by Admin »

PonoBill

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Re: Print to Ride
« Reply #38 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.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

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Re: Print to Ride
« Reply #39 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.



« Last Edit: January 03, 2023, 05:21:01 AM by Admin »

PonoBill

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Re: Print to Ride
« Reply #40 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.

« Last Edit: January 03, 2023, 11:37:56 AM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PonoBill

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Re: Print to Ride
« Reply #41 on: January 03, 2023, 11:55:29 AM »
What is the inside and outside diameter of the tube you are designing for?
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PonoBill

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Re: Print to Ride
« Reply #42 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.
« Last Edit: January 03, 2023, 01:09:31 PM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

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Re: Print to Ride
« Reply #43 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.



« Last Edit: January 04, 2023, 06:55:48 AM by Admin »

PonoBill

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Re: Print to Ride
« Reply #44 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:


Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

 


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