What plane should I add the Prandtl-D Wing to?

  • Mini-Arrow

    Votes: 20 37.0%
  • FT-Explorer

    Votes: 15 27.8%
  • FoamyDM-HS Carrier

    Votes: 7 13.0%
  • FT-Simple Cub

    Votes: 7 13.0%
  • FT-Tiny Trainer

    Votes: 13 24.1%
  • FT-Bloody Baron (somehow)

    Votes: 7 13.0%
  • Airliner

    Votes: 14 25.9%

  • Total voters
    54

FoamyDM

Building Fool-Flying Noob
Moderator
I spent a few moments putting this back together. Give another shot.
IMG_20191016_234455952.jpg IMG_20191016_234432037.jpg IMG_20191016_234438315.jpg IMG_20191016_234443759.jpg
Now I should be ready to give it another try.
 
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FoamyDM

Building Fool-Flying Noob
Moderator
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

New member
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

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

FoamyDM

Building Fool-Flying Noob
Moderator
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

Wake up! Time to fly!
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

Building Fool-Flying Noob
Moderator
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

Legendary member
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.
IMG_20200110_150750.jpg

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.
 
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Crawford Bros. Aeroplanes

Legendary member
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.
IMG_20200110_165928.jpg

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.
 

FoamyDM

Building Fool-Flying Noob
Moderator
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

Active member
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
 

FoamyDM

Building Fool-Flying Noob
Moderator
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.