Unrealised invention
I have quite a few unrealised inventions in my mental cupboard - sure I would be rich if I had done something about them - sure you have had the same things...
One of them was an electrical drive to L/R Main Wheels, powered by the APU which would allow a/c to move independently of Tractor and of Engines.
There - now I have given it away and someone else will be rich instead.
FC.