The Mugi coroplast wing - free plans - RC Groups
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Jun 01, 2004, 05:47 PM
Piscine Promulgator
surfimp's Avatar

The Mugi coroplast wing - free plans

I didn't invent this plane, and it's been around for quite a while, but since I've recently built another one of them and had fabulous success with it, I thought I would post.

First off, the Mugi is a delta flying wing that can be built easily in 1-2 hours from plans available for free online:

The plane has a devoted following both as a slope soarer and as an e-powered aircraft. I only fly slope so I can't comment on the e-powered versions, but those that fly them seem to like them quite a bit.

I've just built my third Mugi. It's 40" wingspan and features no vertical fins of any kind (the basic Mugi design does incorporate a vertical stabilizer in the form of a spoiler, however). Mine is a pure nurflügel ("only-wing") airplane. I used standard sized servos, a Hitec 555 receiver, and a standard square 600mAh flat pack. AUW came to 19oz and wingloading to 6oz/ft^2.

The performance is excellent. It flies fast, has a very high roll rate, is extremely durable and a kick in the pants to fly. I grin like a schoolboy everytime I take it out. It needs around 12mph+ at a decent slope to fly happily (and controllably). Having no fins makes it a bit less tolerant of slow flight, but landings are no problem--you can hover it down like a helicopter.

2mm Coroplast is used to build the plane. It is available online in the US from, as well as often being available from craft stores and similar. Be sure to get 2mm Coroplast as the 3mm and 4mm stuff is too heavy to make a nice plane at this size (in other words, you'll want to scale it up to keep the wingloading low).

So, I'm sure most people have heard of these planes already, but please do try one out at some point. I'm sure you'll find it interesting and cool!

Here's a picture of me with my Mugi...

Latest blog entry: Of Fish, France, FPV, and Fun!
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Jun 01, 2004, 05:48 PM
Just fly the darn wing!!!
ScYcS's Avatar
It looks cool......pretty heavy for a 40" wing though....might be tough to launch it with a SP400 motor.
Jun 01, 2004, 05:51 PM
Piscine Promulgator
surfimp's Avatar
You'd have to check the Mugi Yahoo! Group for more info on that score. I don't fly powered aircraft so I have no idea what it takes in that regard. But it is discussed pretty regularly on their mailing list.

Latest blog entry: Of Fish, France, FPV, and Fun!
Jun 04, 2004, 04:10 AM
Mugi Pilot
Moogee's Avatar

Finless fourturn

Thanks for spreading the word, dude!
After reading all your bits on rcmugi about the finless I thought I'd see what happened if I flew my brushless E-Mugi sans fin.
The results were impressive! That's the results of my laundry detergent

The thing was scary!!! After launch I went for standard vertical climb out but the 'rotation' to vertical was a little fraught as the Mugi was very barrelly and refused to track its usual straight line.
At altitude I flew a few circuits - the Mugi being very twitchy and just itching to fall into turns. I then tested the stall, pulled vertical again and backed off the throttle.

At this point, the Mugi started spinning - flat spinning! I actually suspected that a battery had fallen down one wing as there was nothing I could do to regain control. After a few bursts of full throttle (which is a lot of thrust) I managed to shake the spin. I lost about 100 ft.

It was singularly the scariest moment of my short flying career as I had no idea where the plane might end up. I'm back to finned flying but I suspect one day I must recreate that spin and video it for the new site.

Glad yours worked out with your modifications. Looks cool (and so does the hat :-)

Jul 16, 2005, 08:45 PM
elaerico's Avatar
A question:
Here in Argentina are not available the coroplast. Wich other material can I use in your construction?
Jul 17, 2005, 03:58 AM
Registered User
Originally Posted by elaerico
A question:
Here in Argentina are not available the coroplast. Wich other material can I use in your construction?
Depron or fanfold foam should work fine. You will probably need to add some stiffening in the form of carbon tubes and/or light ply spars. In addition with foam make sure you tape up at least the leading edge te reduce damage on 'too fast landings'. You may have to add some additional weight if you intend to go sloping. For powered flight the lighter weight will work fine.

Actually the Mugi and the Pibros more or less follow the same planform, but with different materials. You can find plans for the Pibros on different websites. Just do a Google search for '+rc +pibros' or go to e.g. or
Jul 24, 2005, 07:17 PM
Registered User
vertew's Avatar

New Mugi - with lights on


Here's a pic of my new Mugi Evo. It's about 90% done (motor + ESC are just taped on), but I couldn't resist uploading a photo with its lights on. Similar effect the pic on -- should be bright enough to fly at night with!

- Mega 16-15-3
- Lipo 2000 3s
- CC Phx 35
- Micro radio gear

I've got a CG problem at the moment. The current balance point is about 40mm back from the rear most servo strap hole. Looks as though I need to do more moving stuff about / adding nose weight. Anyone got any suggestions?


Jul 24, 2005, 11:45 PM
Registered User
Don Sims's Avatar
Any way to move the battery forward with the light there? Or perhaps the motor?
Jul 25, 2005, 01:20 PM
Registered User
vertew's Avatar
I've shifted the lights & battery forward as far as possible (battery mounted cross-wise). Have moved the motor forward about 1cm. Also added 2oz of lead to the nose. The CG is now about 2cm behind the rear servo strap hole.

I'll maiden it this weekend and see what happens ... !

(PS - must work out how to post thumbnails - can't get the [gallery] tags to work - post preview keeps showing a broken link, even though link path looks correct)
Jul 27, 2005, 09:28 AM
Mugi Pilot
Moogee's Avatar
Hmm, just been thinking. 40mm back from the rearmost cable tie hole should be 210mm from the 'inner nose' of the Mugi. That should actually be Ok.
When you fly it, try a left hand roll - if it's balanced perfectly the roll will be astonishingly fast and axial. A rearward CG will manifest as a slower, laboured roll and will be barrely.

You've made me think now about the plans/instructions. I put 200mm back from the nose. I'm actually meaning 200mm back from the point where the two diagonal folds meet, not the tip of the exodoubler which will vary from craft to craft. Perhaps a modification to the instructions is in order.

Thanks for making me think on that one! - and still really liking that colour scheme!
Jul 27, 2005, 10:06 AM
Registered User
vertew's Avatar
Hi Morgan - as you know I've flown the Mugi now and it goes great. A real howler in fact. From what you say, the CG might be slightly too far forward with the 2oz of nose weight. I'll experiment ...

I'll also add some 'tracksuit stripes' for visibility as it's tricky to spot in daylight. Longer term, I can see myself building a high visibility daytime mugi to go with the nightime one.

Have to say - I'm very impressed with the simple/light/strong design and brilliant supporting website ( I built mine in a couple of days.

Jul 27, 2005, 12:05 PM
Robots... robots everywhere
minifly's Avatar
to make thumbnails, go to the 'manage attachments' below the 'submit message' button, find the picture you want, click upload and you are done!
Jul 27, 2005, 01:03 PM
Registered User
vertew's Avatar
Ahaa - great thanks. Here's another pic (I hope) of the completed Mugi ...
Aug 03, 2005, 07:42 PM
Registered User
vertew's Avatar

Mugi video - dusk flying with lights on

I've made up a video here of my mugi doing some dusk flying at the weekend. It's 17Mb.

Note - the clip uses the DivX codec, which most should have but if you don't, go here to the free download/install.

cheers, andrew.
Aug 03, 2005, 09:10 PM
lone wolf
rcaddition's Avatar
I loved flying my night mugi. You have to be able to almost memorize (map out) almost every movement you make in flight. After a while flying in complete darkness was pretty easy. As for the cg problem, I used a very heavy 12oz 3s lipo which took care of the problem. Its amazing how well the mugi flies with this heavy battery. The mugi I now fly has the nose extended forward about 2in and I use a lighter 3s 2100 lipo(6oz). here's a post with a pic. In the pic you can see how I use coro to help extend the nose. the pilot was donate by by 4 year old daughter.

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