I have read something about Avro York pilots lowering the u/c and flaps in massive updraughts. This allows them to control the speed without reducing the power too much and over cooling the engines. I think it was Nesbit Duforth(?) who used to write splendid articles in Pilot magazine.
In one of his articles he describes an experience when he was still climbing with full flap, u/c down and the engine power reduced as much as he dared.