Apparently Foam Board is a valid construction method.

I thought I was unique in using it. Apparently not. This guy, this guy just won the internet of scratch built aircraft.

http://inspire.eaa.org/2017/11/21/airventure-2017-inspires-homebuilt-foam-board-ultralight/

(Direct links)
https://youtu.be/KidFSfdb8t8

https://youtu.be/0V7z4uAeVdc

https://youtu.be/GjQ48hrLx34

https://youtu.be/biZ2Sl63nr0

https://youtu.be/xEqCt7GZo7M

https://youtu.be/O6sy5bt4D-Y

https://youtu.be/eNSN6qet1kE

When electric took off in modeling 10-15 years ago there were more twins made as you could really depend on both motors running. This guy has used similar logic in full size. Although he was probably pushed into a twin arrangement due to time. He needed something cheap and available online to make a deadline.
But now the question looms: who will be the first to hot-wire a really cool looking light twin that's as safe as a single? With the added spar depth and Marske rods in the spar caps you could make an electric foam monoplane twin with decent structural efficiency. Although the public is not really interested in tech, tech can now enable perfectly safe and most cool appearing twins that might spur interest. There would need to be some recognition from the FAA that electric twins are safer than gas singles and should not require expensive twin training. 'Cuz a mono will never make Part 103.

Very Cool

What a great young man doing what he loves. Too bad there are not more young people like this rather than those that just want to stand around on the corner and get in trouble.

Sripol spent a $$$ fortune on batteries, which makes his build less fascinating. For what he spent on batteries alone, he could of bought a very nice great condition ultralight, which kind of defeats the purpose of building an airplane, ihmo, or built something much cheaper using an existing design.

But he has a long RC history, so it was more a personal challenge. I think his fan base pretty much paid for his airplane when he asked for money for a BRS, and his fans way overcompensated, thinking he was going to get himself killed in his flying styrofoam cup.

He's built other foamy flying RC's. I think he was involved peripherally with Flight Test at one time, and I know they scratch built a lot of large foam RC's, probably most notably this giant Star Destroyer.

some folks "fortune"'s are more than others

I believe there are better battery choices than his, but the expense of his choice didnt raise any thought on my part.

I am an rc guy, but my man carrying aircraft never mimic my rc's as closely as Sripol's creation mimics r/c. I applaud him!

welcome Choppergirl!