Re: Any interest in a Group buy of Polyimide tubing?

From: <leop_at_lyradev.com>
Date: 11 Jan 2014 10:14:33 -0800

I use my copy of a Ray Harlan's post sander (plans from Ray in some previous issue of INAV) to initially round the spars. Then I finish and get the final size by pushing/pulling the spar through a jeweler's draw plate, coming in from the reverse side so that the sharp edges of the plate act as a spoke shave. Going in from the front side just compresses the wood rather than shaving it to the shape and size.
 

 The wing post fit is loose enough so that the tube and post slide easily by hand but do not move in flight. Sometimes a bit of repositionable glue stick on the post is need to tighten up the fit. For prop spars, the fit is a bit tighter but the spar can still be removed or repositioned in the tube. I find that such a fit is not good enough for flying as the pitch can change at high torque, when steering, or during a hard crash into the ground, wall , or girder. I lock the prop spar and tube with a drop of Ambroid. Of course, I need to first precoat the end of the tube with thin CA.after I rough up the surface of the tube with green Scotch-Brite. Ambroid will not stick to polyimide but CA will and Ambroid sticks to dried CA.
 

 LeoP
 

Received on Sat Jan 11 2014 - 10:14:34 CET