View Single Post
Old Jul 30, 2012, 05:38 PM
balsa or carbon is offline
Find More Posts by balsa or carbon
Hot glue held together by foam
United States, WA, Vancouver
Joined Aug 2010
4,156 Posts
Quote:
Originally Posted by DuPageJoe View Post
I have a few questions and findings on the Super Easy. Iíve started cutting and weighing foam board, and also put the wing and keel drawings in TurboCad. Given the shape of the plane, that was easy, too.

Most important - Do you strip the paper covering off the expanded foam board, or do you leave it on for reinforcement?

I found that my foam board weighs 230 grams a sheet with the paper on, to give an airframe weight of about 10 ounces. The sheet was marked Elmerís. Itís been in my basement a while, so I donít know where I bought it. The paper on it weighs about 16 grams per 100 square inches, figuring out to almost ĺ the weight of the board.

From the drawing, I found the CG of the wing panels to be about 21 inches back from the nose, so stripping off the paper would shift the CG of the finished plane quite a bit forward.

I found that the dihedral angle with the wing tip raised 7 inches was nearly 20 degrees, but whatever works.

Iím thinking of putting a KFM panel on top of the wing from the nose to 12 inches back. It would reach about 40% of central chord. I figure it would be worth putting on to reinforce the nose and shift CG forward. Iíve stripped the paper off the parts of the wing and the added panels that touch, so weight added is decreased. The modification would add about half an ounce plus glue.

Originally, I thought of using a one ounce CDRom motor with a GWS 7X3.5 prop, but the weight of the paper might make a 28mm X 30 mm outrunner with an APC 7X 5 prop a better fit. I made a firewall on a stick mount out of plywood and 3/8 inch square bass wood for it.

The pictures show my drawings so far. The one of the wing has a line on it where the area is the same toward the nose as toward the tail (about 150 square inches on each side of the line for the one panel).
I leave the paper on and add carbon rods for reinforcement . Nightstone had great success by taking the paper off and covering his with packing tape .
I think the Elmer's board is a little heavier than the Dollar Tree board , but I don't know for sure .
I put that much ( 7" ) dihedral in because my intention is for the Super Easy to be a total beginner plane , both for building and flying . The one I built with 7" dihedral ( and quite a bit of up elevator trimmed in ) rights itself if you let go of the sticks .
balsa or carbon is offline Find More Posts by balsa or carbon
Reply With Quote