Author Topic: Infinity Tails  (Read 5534 times)

Admin

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Infinity Tails
« on: April 19, 2023, 05:43:44 AM »
I am pretty stoked on the concept of the Prantl style box wing adapted for use as a hydrofoil tail.  I see a lot of potential benefits.  Optimized for lowest possibe induced drag / wake turbulence / Management of vortices.  Compact form factor: The 230 mm wing below has similar span, area and voume as my Axis 400.  Yaw magement (3 vertical symetrical airfoil sections).  Safety.  Prints are extremely stiff at any thickness due to the 3 vertical elements.  One piece, 30 minute prints at $5.00 cost.  Ready to ride with no joining.  Light sand and seal suggested.  Lighter than same size (combined lift generating span) carbon laminate wings with hardware.

This latest one connects the fuse to only the center vertical stabilizer, uses matched cambered profiles at -.75 degree incidence for the horizontal elements and symetrical vertical elements (all designed for my Reynolds case - SLOW, OLD and COLD).

I will have a bunch of variations advanced out and ready for input by Gorge summer (assuming that is still a thing).
« Last Edit: April 19, 2023, 06:06:07 AM by Admin »

daswusup

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Re: Infinity Tails
« Reply #1 on: April 19, 2023, 06:10:06 AM »
these are super cool Admin! Is it possible that an infinity tail could be narrower wingspan than a regular and still provide plenty of lift because of the double wing? I really like the safety aspect(pun). It's really cool all the foils and parts that you have been printing up all winter. You are a pioneer. How hard would it be to print a box front wing?

Admin

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Re: Infinity Tails
« Reply #2 on: April 19, 2023, 06:35:25 AM »
these are super cool Admin! Is it possible that an infinity tail could be narrower wingspan than a regular and still provide plenty of lift because of the double wing? I really like the safety aspect(pun). It's really cool all the foils and parts that you have been printing up all winter. You are a pioneer. How hard would it be to print a box front wing?

Yes, that is exactly whaht I had intended to write.  The 230 above should provide the same lift as my Axis 400 mm due to the double span, but theoretically with less drag.  Will this also result in amazing bankability (roll) associated with a short span and yaw stability/tunability?  Let's see.

I do think a complete wing is possible to print and the stall characteristics are super enticing.  A front wing box will not be hard.  A combo front and tail will be more challenging, but should also be possible.
« Last Edit: April 19, 2023, 07:17:36 AM by Admin »

Dontsink

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Re: Infinity Tails
« Reply #3 on: April 19, 2023, 09:38:56 AM »
Just for the safety aspect they are really cool.
Really interested in seeing how they perform.

jondrums

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Re: Infinity Tails
« Reply #4 on: April 19, 2023, 01:09:27 PM »
a few questions that I don't have answers for:
* do we want vertical stab(s) on the tail?
* I guess the drag of the tail comes from lift induced drag and surface area drag.  Is an infinity tail a more efficient way to get the lift (downforce) we need with minimal drag?

Admin

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Re: Infinity Tails
« Reply #5 on: April 19, 2023, 02:26:36 PM »
a few questions that I don't have answers for:
* do we want vertical stab(s) on the tail?
* I guess the drag of the tail comes from lift induced drag and surface area drag.  Is an infinity tail a more efficient way to get the lift (downforce) we need with minimal drag?

If we lose some yaw stabilty due to a shortened distance from mast position to the COG (also the axis of yaw) then vertical stabilizers may offer a nice way to tune that. 

Here is some cool research https://osf.io/3r79q/download

They wrote, "Our results reveal an increase in the lift to drag (L/D) ratio of the wing by 25 % and a delay in the model’s stall angle by +6° compared to a monoplane"

I like the idea.  I have a zillion questions on how best to configure it.  Fortunately, we can make changes very quickly and try a lot of variations.  These would be very difficult to build conventionally. 


PonoBill

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Re: Infinity Tails
« Reply #6 on: April 19, 2023, 08:14:31 PM »
Looking at hydrodynamic and aerodynamic theory this is probably the lowest drag configuration possible (highest lift/drag ratio). It isn't done because it's near impossible to fabricate. Oh, wait...
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: Infinity Tails
« Reply #7 on: April 20, 2023, 04:25:19 AM »
Yup.  Electric planes may be the motivation to get this done but for aero it has been brutal.  Check out this vid.  Imagine getting into that process and seeing a way to improve the design.  You are locked.  We can print that wing and change it a few times in a week.

This Synergy wing config is full system replacement with a unified uplifting front wing with a downlifting tail, but others use two uplifting wings.  On the tail above I have two downift wings as this is only a tail. 

https://www.youtube.com/watch?v=NJGTWvK6wVY

tarquin

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Re: Infinity Tails
« Reply #8 on: April 20, 2023, 09:16:02 PM »
Awesome effort. Well done. Don't know if you have seen these but some interesting ideas from Horue.

https://youtu.be/IiCAeBHArL8

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Re: Infinity Tails
« Reply #9 on: April 21, 2023, 02:27:49 AM »
Super interesting and great to see them trying this stuff.  It is clear that there are a lot of directions that can work, even if you can find some theoretical problems. 

We are at a unique moment when things are changing and these ideas becoming possible on all levels.  Have a look at the Lockheed/NASA project below.  Not a lot of details but it looks like two uplifting wings (not the staus quo downlift tail) with the front wings rooted far forward of current and engines back.  All of that says to me that the have moved COG between the wings.  Consider if we did that.  Ditched the downlift stabilzer and replaced it with a boxed, staggered uplift wing and then centered that assembly under COG.  Very rough thoughts at this point but I think it is worth trying.   We could print that.

https://www.nasa.gov/topics/aeronautics/features/greener_aircraft.html

Lockheed Martin took an entirely different approach. Its engineers proposed a box wing design, in which a front wing mounted on the lower belly of the plane is joined at the tips to an aft wing mounted on top of the plane. The company has studied the box wing concept for three decades, but has been waiting for lightweight composite materials, landing gear technologies, hybrid laminar flow and other tools to make it a viable configuration.

« Last Edit: April 21, 2023, 02:39:42 AM by Admin »

Admin

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Re: Infinity Tails
« Reply #10 on: April 21, 2023, 02:57:40 AM »
Here is a nice vid of a free to download RC 3D printed version.  Probably a down tail?

https://www.youtube.com/watch?v=SZY6YwRDAT0
« Last Edit: April 21, 2023, 03:16:29 AM by Admin »

tarquin

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Re: Infinity Tails
« Reply #11 on: April 21, 2023, 11:41:11 AM »
As they say they have been studying it for three decades. The whole NASA, Lockheed, Boeing limitless budget died years ago. The amount of money being spent in the AC boats far exceeds their R&D these days. Obviously Boeing is involved now and since F1 budgets got capped a lot of people left F1 and followed the money and went to AC teams.
 

tarquin

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Re: Infinity Tails
« Reply #12 on: April 21, 2023, 12:21:34 PM »
Also the hybrid laminar flow is interesting and what can potentially be done. Looking at different finish on the top and bottom of the foil. Very easy with 3D printing. Then moving further into being able to control the foil shape.

SUPladomi

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Re: Infinity Tails
« Reply #13 on: June 19, 2023, 02:46:56 PM »
Can't believe I somehow missed this thread! So cool!

burchas

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Re: Infinity Tails
« Reply #14 on: June 20, 2023, 07:51:57 PM »
Here is a nice vid of a free to download RC 3D printed version.  Probably a down tail?

https://www.youtube.com/watch?v=SZY6YwRDAT0

This thing just feels right. Brilliant 8)
in progress...

 


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