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100" 70mm EDF U-2 Dragon Lady


Elite member
I worked on a MiG-21 for a while and that had a really high wing loading so I want to try something in the opposite direction. The U-2 is one of only five planes in service with the USAF for over 50 years and was designed back in the 1950s by Skunk Works. I'm really excited to attempt an airplane with this large of a wingspan, everything I've made in the past has stopped at around 6 feet in width. With a wing this long, do you guys think a more heavily reinforced spar will be needed? I've built the nose section and it took an entire sheet of foamboard. This is going to be an exciting build.
U-2 Nose.JPG
U-2 3 View.gif


Elite member
At the end of the day, weight vs lift and overall speed/g's is what is going to decide that question.

What is your overall weight expected to be? This is going to determine what kind of structure you will need.

With the information given, just using my gut, I would recommend something other than a foam spar.

If I was you, I would start with more than what you think you might need. With the wing span you are talking about a few extra grams is not going to hurt your flight performance. You do not have to use something exotic like carbon fiber tubes, wooden dowel at your local craft store would work just as well.

I can't wait to see this build!


Elite member
Overall weight is probably going to be around 1800g (I'm high-balling it) and at the moment I am planning on using box spars with some paint stick reinforcement. How would i fit a dowel rod in? Along the bottom of the wing?


Elite member
Here is what I use for my larger builds...
It's cheap, it's local and it's plenty strong. It's just about the same size as two layers of foam so it's easy to build around.

That said, having these out just a second ago made me realize just how big you plan on making this wing. I would do some experiments first. That's a whole lot of wing.


Elite member
Thanks! Regrettably, I painted it black and brought it to FFO where the added weight meant that it had a much harder time climbing to any altitude.


Building Fool-Flying Noob

This is admittedly, a long time coming, but it worked out rather nicely.
I'm not sure how I missed this... YEARS ago. but You have done great work here. I would love to know what you ended for the wing section. did you taper the edges?

Great work!
How does it glide? What "missions" have you done?