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Monday, January 12, 2009

Time for a build thread

Actually this will be a rebuild thread, and I will attempt to cover my methods used to put a crashed glider back into the air, in hopefully better condition than before.

During our recent slope outings Ken from JOMAC had the misfortune of crashing his Celstar GA-1 glider after it's one wing folded, fortunately he dutifully cleaned up the crash site and collected all the debris. On inspection the wings were damaged, one quite badly where it had folded and some impact damage on the tips. The fuselage was in three large pieces and crunched on the nose.

I asked Ken if I could have the pieces, to which he agreed as long as he could strip out the fittings, linkages, servo's etc. Ken has a mould so he can build another. I, on the other hand don't. But the Celstar would be nice in my collection, being designed for aerobatics, and built in Ermelo.

The Celstar was successful in the 1991 world aerobatics champs and two remain registered for flying to-date, one in Switzerland and one in the U.S.A. ,the third one is still in South Africa but apparently requires some work. I managed to find very few photo's of the original, but there is one nice shot of the South African one in the old orange/red and blue SA airways colour scheme which I will respray it in.

Always recover a crashed plane with all its pieces, on closer inspection and after the dissapointment dies down, a viable repair is often possible.

Here are the basic steps to repair:


I have cyano-ed all the pieces back together and added some sika-dur epoxy outside across the cracks for support.


The inside is sanded clean of paint,and any steps or sharp edges. I tackled this with my power sander and ate away some of the canopy lip by mistake, this will be repaired.


Next I lay up some squares of 163gr cloth and epoxy on a mylar sheet. Once it's wet out I tranfer it to the inside of the fuselage, across the breaks.

I could just reach the area behind the wing, I press it against the inside surface and add more pieces until the whole tube/break is repaired.


AHHH Carbony goodness...... some 60k carbon tows will beef up the undercarriage and canopy lip as well as breach the front damaged areas.

The off cut Hybrid cloth re-inforces the join and adds some strength, the canopy lip is being re-built with glass and a mix of cotton/glass flocks and resin.


The clear canopy was totally destroyed so a new one is carved/sanded from blue foam and will be layed up as a form for a new clear canopy and a sprayed black one as a spare.


The outside of the fuselage has been wet sanded after filling with a resin/micro balloon mix and once all the holes are gone and the shape is correct. It has been painted with an etch poly-urethane filler/primer. This primer and the old paint will be water papered with 320 grit paper and prepared for the masking and spraying of stripes first and then the white.

Thank you, wings next.

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