Mugi, A Construction Article
I was at the field recently and Rich Caine showed me his new Mugi, an all coroplast flying wing, a new plane from relatively old web based plans. Since I was getting the building bug recently, thought I’d build one. The plans are online at http://www.mugi.co.uk/ including step by step instructions which are very good.
Everything is made from 2mm Coroplast and glued together. I used foam tac which is a pretty stellar adhesive although not as quick a build as the contact cement idea (see pic at the end of this article); I like to have a bit of work time and let it cure. You build most of the mugi in the flat and then fold it up to make the air foil. The servos are mounted with cable ties and double sided tape.
Below is the base sheet with carbon tube spar and servos mounted. You can see the score lines for the fold and pushrod exit slots.
Mugi in the Flat, Pre Fold Operation
Following is a pic after the fold with the trailing edge clamped. The wing camber is pretty severe, max height is about 25mm.
Mugi Post Fold, with Trailing Edge Clamped
Rear view Clamped
Here are some weights for reference
ESC 40A plush, Hobby King
5x5 APC, 35A, 350w. I like this one
Servos HS225MG although 46oz-in is ok
Wing area 528 sq in
Watts/lb 350w/1.5lb = 230w/lb
Nose weight for ballast 3 oz
Here is the final version, I painted the top for better visibility. I’ve always found red and white to be the best visibility for me. I used some 4mm coroplast for the ailerons which fit well since the trailing edge was doubled 2mm.
Here is a pic of the foam tack adhesive by Beacon that I mentioned earlier. It sticks to EPP, depron and most foams as well as coroplast, and dries a bit flexible so is very strong. I use this stuff on everything these days.
The Mugi was an interesting build, clearly something different, yet relatively quick compared to stick construction. And it’s relatively fast and cheap! What could be better than that?