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 Sailplane Construction Project Session #71

Comet Sailplane Project 
Most of the wings and stabs on my R/C ships are covered with UltraCote Lite. They get a light sanding and then with carefully sticking the film down I am through. However, I could not cover the classic Comet Sailplane with any kind of film (sandwich wrap as Larry Davidson calls it). I have waited most of my adult life to build the Comet Sailplane and it simply has to be covered with silk. Having said that, there is a tremendous amount of work in silking as you well know. To begin with, every part of the structure that is going to be covered has to be dope three times with light sanding between each of the coats. To make the silk covering bullet proof (long lasting), I first cover the structure with a base covering of Polyspan Lite before applying the second silk covering. However as with everything, there is a technique to covering with Polyspan Lite, which Larry Davidson has been most helpful in instructing me on.
I began covering the horizontal tail this morning around 9:00 a.m. and did not stop until 4:30 p.m. and I still have to cover the top of the stab tomorrow morning. I started by covering both halves of the elevator just get Larry's technique worked out. Once they were covered, I gave each surface two coat of 50/50 nitrate dope. As you can see, the technique worked very well.
On the stab, I started with the bottom of the stab's undercambered surface this afternoon. In addition to the three coats of 50/50 clear nitrate dope with light sanding between each of the coats, I applied two more coats of unthinned raw nitrate dope to bottom edges of the undercambered ribs to insure adherence of the Polyspan Lite covering. My wife Sue took this picture of me working on the stab's bottom covering. 
This is a picture of the stab's bottom covering once I finished trimming the edges.
This is another shot of the bottom covering on the three foot long stab.
In this picture, I am attempting to show you how well the Polyspan Lite covering stuck to the bottom of the heavily doped undercambered ribs. No dope has been applied to the covering yet. Tomorrow I will cover the top of the stab and then dope both sides of the stab at the same time..................Tandy

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