Mechta
The Challock (Kent) T21 is fitted with a tape deck and speakers which is used to play ......you guessed it!
(and it has a bomb rack, strictly for jettisoning water ballast you understand)
Spekesoftly - sorry, got my Costins in a twist there!
Mary - The other year at the International Vintage Rally at Tibenham, Ken Wallis turned up with a very neat 2 stroke engine (formerly a ME 262 starter engine) and propellor mounted on a pylon. Apparently it had been fitted to one of the Petrels at Redhill early post war. The CFI (Lorne Welch) immediately said "You're not flying that 'ere" or words to that effect - but they did, a couple of times before the Petrel reverted to being a glider. Again because of the risk of gliding being "contaminated" by engines.
I think that self sustainers and self launchers are now reasonably well accepted in gliding (except when they get home and I don't!)
The feature I liked best about the engined Scud 3 was that it apparently had a hand throttle fitted to the wingtip so that the wing walker could "taxi" it out to the launch point. Now that's what I call advanced thinking!