My final 3 clues:
27 across - It's rain, wind and gravitational acceleration destroyed spiralling lfight (7,5)
I have -I-D-N- / S-A-R
Winding stair? (But there's "wind" in the clue)
36 across - Caution affecting navy holding fear back (8) I have -O-O-A-N
(Novocain????)
51 across - Copy traveller that's stripped racily on the way back (7)
I have R-P-I-A