Originally Posted by
Mnewton
I think it was Mrs Hepple T21 VX275 ? that on a major overhaul they found all the glued joints
in the wing were completely dry and cracked as in not attached, only held in by the covering.
Just found more on Mrs Hepple at
https://www.key.aero/forum/historic-...intage-gliders
It is far more likely that 275 (it was quite old) had been constructed with the old non waterproof glues of the time, that used to fail when they stayed damp.
This was a common problem on all early wooden machines and the main reason they failed their COA's later in life.
The replacement 'Aerolite' was a 'two pack' system that required the use of a hardner. and then had to be applied quickly.
To ensure the hardner had been added it was normal for it to be dyed therefore ensuring the joint was sound.
As most ATC gliders were hangar stored I do not think water ingress into the structure was a problem.
On a bit of a 'creep' Gp Capt J Kent obtained a Comper Swift after the war and kept it at Tangmere. When it came up for its COA it went into the Station workshops for its inspection where they found the machine in fine order 'apart' from the glue joints. Normally the labour required for this would be uneconomical, but the C/Tech in charge decided it would be an ideal opportunity for several members on the staff to do their 'trade tests' on the real thing.
They used all the original wood but 'fixed' with aerolite, and that's why the machine survived. The main spars were solid spindled so not affected.