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 ready to fold.JPG

 

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 in clamp.JPG

 

Mugi Post Fold, with Trailing Edge Clamped

 

mugi post fold in clamp rear view.JPG

 

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. 

 

Mugi final.JPG

 

Mugi Final

 

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. 

 

 

New Glue

   
   

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?

 

Happy Flying!

 

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