Thread: Discussion UMX inspired Yak
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Old Nov 30, 2010, 09:36 PM
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UMX inspired Yak

Inspired by the new e-flite UMX Extra 300, I decided to make a Yak 55 using the same construction technique and the 4-site electronics.

The planform is as close of an approximation to the extra as I could guess from the stock photos, stretched about an inch to match up with the Yak 55 fuse. I drew up the profiles in SolidWorks and laser cut the parts from 3mm Gediplac.

The foam parts were skinned with 0.35mil painters drop cloth from Home depot. The smallest package they had was 3600 square ft, so I've got enough for a few (thousand) more. The drop cloth is about the same weight as the mylar covering used on the vapors, and presumably the new extra, but it will stretch a bit more before tearing. I attached it to the foam with a dusting of 3m77, and used the skin as a hinge for all the control surfaces.

I used all the carbon and hardware from the 4-site, lengthening the pushrods about an inch. The gear is a bit short, but is good enough for now.

The finished weight came in at 32.3g, with a TP 150 cell, which is almost exactly the same as the extra. If I cut another there are a few places I'd beef up, but I think I could still keep it around 32g.

The plane is awesome to fly. I was really surprised how much better it feels than the 4-site. Rather than just being a micro that can do some 3d, it flies like a standard sized 3d foamy (just in a much smaller space). Minimal coupling, and very crisp all around. The drop in weight is noticeable, and there is reserve power when you need it. If Extra flies similarly Horizon's got a real winner.

Better video, and version 2.0 to come.

Micro 3D Yak (1 min 15 sec)

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Last edited by AJWoods; Nov 30, 2010 at 09:38 PM. Reason: added video
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