dtfb prandtl motor glider

[badpilot27]

I was a bit board so I decided to make a 50in prandtl d flying wing using similar build technique that was used in this video except I added a lower wing surface

here's some CAD images

airfoil looks a bit weird about halfway through the wing though

might have to make it a bit smaller since I'm not sure yet if each wing can be made from one sheet of foam board yet

 

[Houndpup Rc]

I was a bit board so I decided to make a 50in prandtl d flying wing using similar build technique that was used in this video except I added a lower wing surface

here's some CAD images
View attachment 249340 View attachment 249341
View attachment 249342 View attachment 249343 View attachment 249344
airfoil looks a bit weird about halfway through the wing though
View attachment 249345

might have to make it a bit smaller since I'm not sure yet if each wing can be made from one sheet of foam board yet

What program do you use?

 

[Houndpup Rc]

Looking good btw!

 

[LitterBug]

Reminds me I need to finish my 3D printed Eclipson PRANDTL builds. Printing is done, just need to finish assembly.

 

[Houndpup Rc]

Reminds me I need to finish my 3D printed Eclipson PRANDTL builds. Printing is done, just need to finish assembly.

cool!

 

[badpilot27]

What program do you use?

onshape

 

[badpilot27]

do any of you guys have any recommendations for how much twist i should use? right now i put 12 degrees of twist but im not sure if that's too much

 

[badpilot27]

making the plans right now. the sketch looks like a mess lol

i wish variables had an option to measure angles though. if I make a change to the design i have to go back and change most of the angles to fit the design.

 

[LitterBug]

I know @FoamyDM made some foamboard PRANDTL wings. Wonder what he used?

 

[LitterBug]

do any of you guys have any recommendations for how much twist i should use? right now i put 12 degrees of twist but im not sure if that's too much

Looks a bit much compared to other models I've seen. Not that they are the golden child.

 

[Houndpup Rc]

onshape

Nice! I am learning that right now!

 

[Michael9865]

Looks a bit much compared to other models I've seen. Not that they are the golden child.

“Not that they are the golden child.” I must admit that statement made me chuckle.
New technics and new ways to look at and accomplish something is always interesting. I enjoy watching this design. The old adage of “there is more than one way to skin a cat” is so true. (Please don’t take offense or report me to PETA. It is an old statement/adage.)
NASA spent a great deal of money to develop and test this wing and hobbyists get to recreate it in their spare time. I love this creative process. I personally enjoy the design, build, fly/test, redesign, rebuild, fly/test process.

 

[theinfamouscoder5]

Looks cool!

 

[badpilot27]

@FoamyDM how did you get a consistent airfoil through out the wing span and much twist did you put in your prandtl wings?

 

[badpilot27]

how would you guys recommend linking up the elevons? the wing tip is quite thin and i don't think i can fit a servo in the wing tip

 

[Houndpup Rc]

BTW when you position your control horn it's best not to have right up in the wing tip because it can cause fatigue.(though usually it's only a bigger deal with really fast airplanes) in the middle is better.

 

[badpilot27]

finished the first version of the plans

anyone know how to convert this into something I can print using normal printer paper?

I also reduced the amount of twist from 12 degrees to 10.5 degrees and lowered the dihedral from 5 degrees to 4.5 degrees

 

[badpilot27]

BTW when you position your control horn it's best not to have right up in the wing tip because it can cause fatigue.(though usually it's only a bigger deal with really fast airplanes) in the middle is better.

thanks for the tip