PRANDTL-D Foam Board Wing by FoamyDM

[L Edge]

Yes. Albion Bowers wrote two white papers on the findings, and has since retired. The Prandlt-D and M projects appear closed, and they are working on other projects. doesn't mean we can't find uses for the findings in our hobby, right?

I am already working on one. They want to design a straight wing (no di, no sweep) and apply a variation version of Prandtl's approach.

Concept Simplified:
It would have a center control for elevator.
2 sets of trailing edge controls on each side of the straight wing. Small deflections.
The outer will be located so when it has small deflections, it would provide proverse yaw.
The inner would be located so when it has small deflections, it would provide adverse yaw.

Result:
When the aileron deflects in a turn, each yaw value(outer,inner) is different. So now we have to add each segment algebraically hoping to come up with the proper roll/yaw combination.

It is fun to explore when things don't exist.

 

[Scotto]

I just found this.

I like how excited he is talking about it.
It looks like it needs air brakes to land. If you imagine a full size commercial one getting in ground effect plus hot air coming up from the tarmac it just wouldnt stop lol. You would probly want flaps too, so maybe a full flying canard would be better. Im picturing like a Beechcraft Starship without the winglets obviously.

 

[FoamyDM]

I like how excited he is talking about it.
It looks like it needs air brakes to land. If you imagine a full size commercial one getting in ground effect plus hot air coming up from the tarmac it just wouldnt stop lol. You would probly want flaps too, so maybe a full flying canard would be better. Im picturing like a Beechcraft Starship without the winglets obviously.

Spoilers and split airbrake would likely do great to slow and "let the air out of the balloon"

 

[LitterBug]

>sigh< Sadly it has been a busy family year both in my family and Wifey's :-(. Hope to get back on track with builds. Indoor fly season has started, and that means so has build season. Eclipson PRANDTL builds are still top of printing/build list.

Cheers!
LitterBug

 

[FoamyDM]

>sigh< Sadly it has been a busy family year both in my family and Wifey's :-(. Hope to get back on track with builds. Indoor fly season has started, and that means so has build season. Eclipson PRANDTL builds are still top of printing/build list.

Cheers!
LitterBug

Great. Life comes before hobbies. I would love some updates when you get to them.

 

[FoamyDM]

The 2nd build of this year's Build-ruary was a swept-back Prandlt-D with an FT Style segmented fold-over wing build.

The last one (looked like a candy corn) I did not have control of. It wanted to roll right.

This one was flyable. I think the CG was aft some (1/4" from the marks)
The build this time was similar the original plank type Prandlt-D. I just cut a ~17° sweep angle from each end and cut the elevons angled to be perpendicular to airflow.


Finished and ready:

Uses an F pack motor(2204 2300kv, 30A esc, 5*4.5*3 prop, 2-9g servos. With a 2200mAh 3S bat)

How'd she fly? Take a look:

 

[FoamyDM]

Take a Look at this... Not a Prandlt-D... but a Paoli. Works similarly.

 

[FoamyDM]

I am still on the hunt for a way to reproduce that proverse yaw flying experience.

Another variation idea popped into my head... something that may be easier to reproduce. A Kline-Fogelman airfoil version. Check back soon. If I make a new one, the glide test will be posted