Turbo Lag

[ARTHUR OKUN]

thats what they use to start BIG jet engines ive seen pictures of those 
air motors in aviation books and they are quite small and turn real 
fast;   in a big jet aircraft they use  bleed air from the apu 
to run it or from anouther working main engine or ground service cart
the apu has an electric motor starter 28vdc. The same bleed air is used
for pressurisation and air conditioning. i think id rather use an 
electric motor for this application .