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Archive for March, 2014
Posted by Jim.Thompson | Mar 24, 2014 @ 07:26 PM | 14,618 Views
During the short breaks in the humid rainy weather of our wet season, I've designed and built a new 1200mm span 3 servo plank.
The wing core was cut from some low density scrap foam scrounged out of a skip at the dump to a PW106 airfoil. I chose the higher camber PW section as I want this one to be as light as I can achieve and be a bit of a floater. Also, I wanted something that will turn a bit quicker than my larger planes, fly in light conditions and be suitable for one of our local beach headlands.

Root Chord: 220mm
Tip Chord: 160mm
LE sweep around 16 mm to keep the 22% chord line straight.
I first applied a 20mm strip of bias woven carbon (using a double carrier sheet), to the LE of the wing and allowed 3 - 4 hours for it to start to cure. Then proceeded with the layup below:
Layup is two layers of 76 gsm plain weave, one @ 0/90 and the other @ 45/45.
Approx 1/3 span overlap of each of the second layers to constitute 3 layers for this inner part of the wing.
Three servos to separate the ailerons a bit and provide better efficiency.

This is made from scrap depron sandwiched between layer of glass/epoxy. I cut out the depron and lined it with 80/20 Fin:100 gsm glass. Then built it up into a box section structure using bulkheads where required. Then sanded to a rounded sort of shape and covered with two layers of 50 gsm glass plain weave fabric/epoxy.

This was hot wire cut to a NACA06 section from some scrap blue foam. Then bagged with two...Continue Reading