PRANDTL-D Foam Board Wing by FoamyDM

[kilroy07]

I’ve almost pulled the trigger on this one, no real specs on the wing to know if it’s based on the same wing of not.... 🤔
https://www.eclipson-airplanes.com

 

[FoamyDM]

So... I can add this to the FTFC20 challenge ?!?! (@rockyboy )

 

[FoamyDM]

I spent a few moments putting this back together. Give another shot.

Now I should be ready to give it another try.

 

[Grifflyer]

Awesome can't wait to see it go!!

 

[FoamyDM]

I have a video - to be posted soon.
I have proof of flight, but one that ended in a destroyed the plane. The wire was pulled from the motor...
It went forward into the wind. Result were an immediate immelman, without recovery (as I ducked, and threw my arm in the way.) busted the prop blades. I'll just have to try again after the holiday.

 

[My77gmc]

Argh...my iPad doesn’t like something about this page 😖

FoamyDM, did you check out the 3D print project on page three of this thread?

 

[FoamyDM]

I did... I need to open your link at home... my work comp doesn't know how to handle an RAR *shakes head*.

 

[FoamyDM]

Here is the last attempt vid

 

[Michael9865]

Here is the last attempt vid

Bummer. Glad it didn't get you though.

 

[mayan]

Here is the last attempt vid

Ouch, sorry to see it pan out that way.

Bummer. Glad it didn't get you though.

+1

 

[FoamyDM]

It turned around faster than I ever expected... I'll try it again soon, but for now. I might have to find more f pack motors or cannibalize a quad.

 

[PsyBorg]

Rule number one is dont lead with your face. So.....
Rule number two is...........

Dont try and catch with your face.

Man you are one lucky brother to not have stitches from that one. wow. Glad yer OK mate.

take these lessons from a person who has done this and knows.......

 

[FoamyDM]

I was glad for two things;
1. it's a pusher. (I felt like I was punching an approaching shark to deflect the bite.)
2. The coat is very thick.

This plane is Simple to build. next time I need to load it up and glide it.

 

[Crawford Bros. Aeroplanes]

Just finished cutting mine out, going to start glueing in a minute. I've gotta get a whole new power system for this one since my smallest battery will never fit.

It's a lot more slender than I expected, it looks really sharp! Honestly it cracks me up that NASA might have spent a few million dollars on this project only to have a few glorified origamists build it in their backyard.

 

[Crawford Bros. Aeroplanes]

I'm thinking I should probably start my own build thread Soon, but for now here's a quick update.
I've got one wing finished and the other almost done.

I'm loving the shape the wing makes, it's just unlike anything else I've seen. I ran out of dtfb building an Arrowhead, so I'm using Ross fb. It has pros and cons but so far I'm liking it, I may use both dtfb and rfb on future builds. The Ross board is more like packing foam than styrofoam, I think it's a bit lighter too. This also means that it's somewhat moldable without removing the paper, which makes shallow curves significantly stronger than dtfb with the paper peeled off. However it is impossible to peel the paper off rfb, which is its drawback.
As a result of this my wing feels very rigid, I don't think I'll have the flexing issues FoamyDM pointed out. However, building this with dtfb would have been much easier, gluing the outboard section with rfb was somewhat hair-raising.

 

[Crawford Bros. Aeroplanes]

Build thread posted for my wing:
https://forum.flitetest.com/index.php?threads/prandtl-flying-wing.61593/

 

[FoamyDM]

Just finished cutting mine out, going to start glueing in a minute. I've gotta get a whole new power system for this one since my smallest battery will never fit. View attachment 154029
It's a lot more slender than I expected, it looks really sharp! Honestly it cracks me up that NASA might have spent a few million dollars on this project only to have a few glorified origamists build it in their backyard.

Right... Remember this concept was nearly abandoned once the other methods of building were proven. (Also simpler to calculate) Once the best ways of succeeding were determined (by NASA et. Al.) It becomes simple-ish to recreate and build. Now we get to focus on alternate methods.

 

[GMalatrasi]

What I was leading to was that I'd like to know if there's a tool to get the twist numbers for different wings since it's a non-linear twist distribution. (FYI the 2016 NASA paper lists a 10° twist from root to tip.)
From all the research I've done, the general design of all the test models have a very similar design.
Ultimately, I'd like to use this concept to get the proverse yaw effect on different designs so I wondered how the geometry changes for different sweep angles. I would assume the published design accounts for the lateral flow due to the sweep.

Recently came across this paper discussing the application of the Prandtl twist on non-swept designs.

https://openscholarship.wustl.edu/cgi/viewcontent.cgi?article=1564&context=eng_etds

 

[Boberticus]

I hadnt read that one yet!

heres one done on the analysis of a forward swept wing. Its weird though, they dont really talk about adverse yaw, just maximun possible lift and the geometries they think are needed, and end up at a different conclusion and re-guards to wingtip twist.

http://www.ijettjournal.org/archive/ijett-v54p212

 

[FoamyDM]

I hadnt read that one yet!

heres one done on the analysis of a forward swept wing. Its weird though, they dont really talk about adverse yaw, just maximun possible lift and the geometries they think are needed, and end up at a different conclusion and re-guards to wingtip twist.

http://www.ijettjournal.org/archive/ijett-v54p212

Thanks guys for the reading material. I have a shop to organize (big chore) and them it will be time to get back into this project.