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Author Topic: Falcon Foil  (Read 5996 times)

Admin

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Falcon Foil
« on: May 27, 2023, 08:39:37 AM »
Hey guys,  This Falcon looking guy has a 620 mm span with 1750 Volume.  The same cambered low Reynolds airfoil for top, bottom and both returns, merged with a symetrical airfoil at the very center of each return to allow the transition so that  both wings can be providing positive lift.  The vertical sub mast is that same Low Reynolds symetrical profile.  It prints in only 3 parts and contains continuous internally bonded carbon tubes tip to tip on the lower wing and half tubes on the upper wing.  Should be ready for testing in a couple weeks.  Thanks for looking!





« Last Edit: May 27, 2023, 08:52:00 AM by Admin »

Hdip

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Re: Falcon Foil
« Reply #1 on: May 27, 2023, 11:26:39 AM »
More glide and a super narrow wingspan? Sign me up!

Admin

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Re: Falcon Foil
« Reply #2 on: May 29, 2023, 10:21:43 AM »
More glide and a super narrow wingspan? Sign me up!

I have the Hub printed now and I am getting really excited about this.  It lends itself so well to the 3D printing environment.  It is going to be really strong and stiff.  I can't wait to try ths one.

Dontsink

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Re: Falcon Foil
« Reply #3 on: May 30, 2023, 07:56:27 AM »
I love this one!.
Even if it were to deliver equal or a bit less perfo compared to a MidAspect that reduced wingspan is going to turn so nice, and the increased safety to body and wing...wow!.

The concept works for sure ( the Bruce Creations protos are proof) but getting the design optimized is going to need a revolutionary building method that allows easy tweaking...a method just like yours :)

DownWindRun

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Re: Falcon Foil
« Reply #4 on: May 30, 2023, 08:56:46 AM »
Wow! That wing looks incredible. So much potential. Any thought on how well a falcon type foil will pump?

Cheers.

Admin

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Re: Falcon Foil
« Reply #5 on: May 30, 2023, 10:31:47 AM »
The Hub is printed now. The wingtips should be done tomorrow. Also pictured is my newest tail to fuselage and fuselage to hub assembly. It allows for easy assembly with a printed bolt and nut sleeve, and maintaining tight carbon to carbon overlaps and a small stainless set screw. The printed parts are not load bearing.

In theory and if well executed: Same lift at half the length with reduced drag and better stall characteristics. Jumpable, unlike higher aspect wings at the same volume. Easier turn initiation, won't pop your air-filled wings, yaw resistant, oh, and safe 🙂

« Last Edit: May 31, 2023, 04:04:09 AM by Admin »

Admin

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Re: Falcon Foil
« Reply #6 on: May 31, 2023, 04:21:10 AM »
Wow! That wing looks incredible. So much potential. Any thought on how well a falcon type foil will pump?

Cheers.

I am hoping it will be an awesome pumper. 

I have the tubes cut and installed now.  The final part is printing.  We should be able to test this very soon.  So cool that this thing has gone from notion to solid in 5 days including 10 hours (arggh!) of design time.  The prints are hands off but they do take time.  I am very patient but I hate waiting :).  This wing is right at the edge of what my printer can do.  The support required is hysterical.  I needed to break the hub into two pieces, so it ended up being 4 total prints.  My original plan of 3 proved impossible based on volume constraints.  I ordered some 100 mm bolts from McMaster Carr as one of the mast bolts goes through the sub mast and is secured under the lower wing.  I added two more vertical carbon tubes to reinforce the sub mast.  Here is a cross section analysis at the center of the hub.

I love working on this one.  You have to feel this thing.  It is a mind bender.

« Last Edit: May 31, 2023, 08:29:34 AM by Admin »

DownWindRun

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Re: Falcon Foil
« Reply #7 on: May 31, 2023, 08:56:13 AM »
Can't wait to hear how it rides.

Am I correct to think that the small span will significantly reduce the stresses placed on the mast to foil (fuselage) connection compared to a larger span foil? Therefore using a 100mm bolt is a non issue.

Also maybe eliminating the need for an HM mast?

PonoBill

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Re: Falcon Foil
« Reply #8 on: May 31, 2023, 10:18:24 AM »
There will certainly be less torque for the same lift.
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.

Admin

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Re: Falcon Foil
« Reply #9 on: June 01, 2023, 11:17:38 AM »
Well, she is printed.  I will bond her tomorrow and then get to sanding.  Every part of me wants to do it right now but I need to get this SurfCowboy off my ass, so I better get down to the water.  Hah!



« Last Edit: June 01, 2023, 11:30:51 AM by Admin »

surfcowboy

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Re: Falcon Foil
« Reply #10 on: June 01, 2023, 08:24:30 PM »
 ;D :D Tracking you across multiple platforms. Haha.

This one has a weird aspect to it for me. Others brought it up and now I have to know. Will this tunnel, which gets smaller due to the foil of the bottom wing, introduce drag due to the incompressibility of water?

Pono, what's the science here?

As I said elsewhere, it doesn't matter if this is a weird bad experiment. The design to production time makes it a full success no matter how it foils. This whole thing has moved the sport forward immensely.

And feel better knowing that Hdip trolls me weekly to finish my latest board. 😂

Hdip

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Re: Falcon Foil
« Reply #11 on: June 01, 2023, 09:48:02 PM »
Do you even have a latest board? It's all smoke and mirrors of the same board.

Admin

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Re: Falcon Foil
« Reply #12 on: June 02, 2023, 05:52:05 AM »
;D :D Tracking you across multiple platforms. Haha.

This one has a weird aspect to it for me. Others brought it up and now I have to know. Will this tunnel, which gets smaller due to the foil of the bottom wing, introduce drag due to the incompressibility of water?

Pono, what's the science here?

As I said elsewhere, it doesn't matter if this is a weird bad experiment. The design to production time makes it a full success no matter how it foils. This whole thing has moved the sport forward immensely.

And feel better knowing that Hdip trolls me weekly to finish my latest board. 😂

Hah!  I need a kick in the butt. 

FWIW, air is also treated as incompressible at biplane speeds.  Here is a bunch of blather I wrote on the group.

On this first try I am staggered at 72 % of chord which is great. My gap is at 78% of chord.  I would have prefered 100%.  I am hoping my stagger compensates for that (the gap is more important if you can't get the stagger).  There is a lot of cool documentation and wind tunnel info on the effects of the positioning of wings for related designs in relation to one another. A general rule of one chord length for gap between the wings is suggested for stacked biplane wings. Stagger or offset helps as well, I have read two theories in regards to which wing forward offers the most benefit, but that is a lesser issue. Incidence for each wing can potentially tweak stall behavior. Prandtl suggested <.20 for wingtip gap to achieve best results at reduction of tip vortices. Some of the info is contradictory. Add in all of the normal factors and you end up with a lot to balance and a lot to try. I see a lot of potential upside to these designs in terms of lift, drag, stall, ease of entry, turn initiation, glide, safety, strength, stiffness, puncture proofing, dock post avoiding, surf friendly, and general badassness. They also lend themselves super well to printing and seem like a beast to build any other way.
« Last Edit: June 02, 2023, 06:28:29 AM by Admin »

Admin

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Re: Falcon Foil
« Reply #13 on: June 02, 2023, 05:55:33 AM »
We also know that similar designs do work  but they have made other choices.  There are a few things on the Horue that I wanted to avoid. Top and bottom mount to fuselage was #1. That is problematic. Also very low gap. That also creates problems. Their stagger looks good on this config, but because they offer various top and bottom wings, that will change based on the chosen components. They also lose the benefit of the closed wing which all but eliminates tip vortices. Bipanes like the Horue actually nearly double tip vortices.

https://youtu.be/I1CVsxE9DlA

bigmtn

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Re: Falcon Foil
« Reply #14 on: June 03, 2023, 11:56:43 AM »
Every part of me wants to do it right now but I need to get this SurfCowboy off my ass, so I better get down to the water.  Hah!



SurfCowboy needs to get his ass in the water too! Hahaha!

 


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