Quite a few months ago I bought a Cosmic Wind from a fellow club member. When I acquired this model it looked a bit tired and I was originally only intending to recover the wings as the film had numerous small holes and patches. The fuselage was a bit grubby but otherwise looked OK. In the end I recovered and re-painted the whole model. Having taken the covering off the wing I found there were a few minor repairs to be made and quite a lot of the wing and fuselage were oil soaked.
Removing the film took ages as I ended up with numerous small pieces of film stuck to the wing frame. The best way I found to remove these is to firmly press packing tape onto the bits of film and peeling it off quickly. If this technique is used be sure any sheeting is firmly fixed otherwise you may end up breaking the sheeting as I did in a couple of places.
When I looked on YouTube for film removal techniques the trick apparently is to heat the film before removal.
When it comes to removing oil I have found the following works reasonably well.
Mix corn flour and acetone so that it has creamy consistency. You may have to do this several times since acetone is very volatile.
Brush the mixture thickly on to the oil affected areas fairly quickly using small brush strokes. The acetone will evaporate almost as soon as the mixture is applied.
Leave for a day or two, remove the corn flour, and re-apply where necessary.
I had to repeat this process many times for badly affected areas but they slowly became noticeably less oily and as the wood became less oily the cornflour was easier to brush off too.
Since I was recovering a model I didn’t really care about getting acetone on the remaining paint work. If treating a small area then you’ll need to make sure you protect the paint work from the effects of acetone which will remove paint and dope.
I have also tried the same method with methylated spirits which is cheaper, less volatile and gives you a bit more time to apply the mixture. It seems to work just as well although I had removed most of the oil by the time I started experimenting with it. I suspect other relatively volatile solvents will work though using something oily, such as turps, would obviously defeat the purpose of this process.
The tail-plane was replaced as it had previously been broken at the join to the fuselage and had been repaired. It was broken again during the paint removal process and trying to make a neat repair didn’t really seem possible. I carefully cut around it ending up with a slot about 3/8 of an inch wide (approx 9mm) which I squared off and packed down to 1/8 inch to accommodate the new tailplane. I kept the original elevator, I should really have made a complete new unit as I’ve ended up with a largish gap between tailplane and elevator where I didn’t spend enough time getting the edges matched. Nevertheless the model seems to fly OK.
The wing is plastic film covered and the rest of the model is Silkspan covered on all solid surfaces for strength and sealing then filled with thinned dope mixed with Sig micro-balloons and sanded with 400 grit paper for a really smooth finish.
The covering film supplied was by Wights Model Aircraft and I was a bit worried that given the low price that it might be well… a bit mediocre. It turned out to be excellent value for money. The backing is easy to remove, it sticks well and shrinks nicely to a drum tight finish and I’m really pleased with the result. Use about 130C for tacking it down and 160-170C to shrink.
Well, I finally finished it and flew the model on 60ft lines on a windy winter day. It had no problems with the wind and it has heaps of line tension. The tank plumbing needed to be fixed since I found the engine would fade at the top of a loop and after my 2nd flight the clunk had somehow worked its way to the front of the tank causing the engine to cut at the top of a loop. I re-plumbed the tank replacing fuel tube to the clunk with something a bit stiffer. I also changed the vents to be arranged more like a conventional stunt tank.
The model is powered by a Merco 35. I don’t know its vintage but I suspect it dates back to the early 1960s, a time when engine manufacturers were predominantly manufacturing non-RC engines. The C/L venturi is cast into the crankcase with no option to change it for an R/C carbie. It also looks very similar to the Merco 35 engine drawn on a 1962 plan (Wallaby – Outerzone) and an engine test I found on Sceptre Flight – Merco 35.
An earlier version of this article is published at Wights Facebook page.