DON'T FORGET THE HORTEN SECTIONS MENTIONED IN RIGHT CORNER. ->
It is not easy to try to convince others that all textbooks about airplane design have a "error". Most books tell that the best way to design a wing is to use a elliptical shape lift distribution. Well, not fully right. Albion Bowers based his knowledge on retro-designing the work of the Horten brothers. And after 11 years he found how they did it. He also found the beauty in that design. And surprise surprise ...all is based on a paper by Ludwig Prandtl dating 1932! Just two pages. It is nothing more. But ...those pages tell it all.
Albion Bowers explaining the principles of the Prandtl project.
Wait a minute... why not let his interns explain how Prandtl works??
Here Al Bowers talks about the Mars project too. It might have a few parts that were told in the previous video. So ...choose. The 8 minute road to wisdom and the nearly hour more detailed road to wisdom. :)
The different NASA Prandtl models
Prandtl-d 1, the rough one
This first model was designed using Hortens method of BSLD (Bell Shaped Lift Distribution)
These are the summer interns doing research on the wing (L to R: Nancy Pinon, Stephanie Reynolds, Sanel Horozivic, Kim Callan, Joe Wagster, Julianna Plumb, Javier Gonzalez, Ronalynn Ramos, Steffi Valkov, and Luis Andrade). The wing was fabricated by Alex Stuber, Matt Moholt, Ed Swan, Eric Nisbet, and Jeremy Robbins..
Here you see more details of the model.
Note the shape of the elevons. They will change later in the later models.
(you can see the details in the collection at the bottom, they are having larger size)
The second model also designed with Horten's system. It was one in nice colours and had a huge sensor at the front.
Albion Bowers holding the second model (Picture by Cam Martin)
Prandtl-d 3, the huge one
From this model on, Albion Bowers used Prandtl's method of BSLD for his models.
Prandtl-m 1 , the small, low aspect ratio Mars proposal
Picture from Facebook page of NASA's Armstrong Flight Research Center
Prandtl-m 2, the one that was not build
This model had calculations, but it was decided not to built it.
Prandtl-m 3, the tiny tiny tiny ones for Mars
Dava Newman, NASA's Deputy Administrator, talks with Al Bowers,
Chief Scientist, about PRANDTL-m, a proposed aircraft for Mars.
(Picture from Facebook page of NASA's Armstrong Flight Research Center)
Pictures of (how they made) the models
Red Jensen told me the following about how they made the moulds: "The molds were milled out of 15 lb. tooling foam on a 5 axis router. They were then hand sanded and finished with resin then primer."
There is no secret about how the models were made. Red calls it usual RC-model making.
In my point of view, this is the way to make your moulds for a full scale composite hangglider. I learned this lesson to late for my DragonWing.