Regarding APU, the B29 that was first recovered and then lost to fire in Greenland had an APU, pistn type fitted. I believe it was a leaky fuel line to the APU that fed the fire.
I worked a lot of Constellations at Lockheed New York. Never saw an APU on any L049 or L749 models, piston or turbine including the VC-121A (L749) of SAMFLEET.
Did see a few turbine APU on some special purpose C121 Super Connies. They were all added as modifications.
Lockheed New York also installed an APU in a VC-118 in the forward baggage. Had a special shroud around it as it was not pressurized inside the shroud as there were cooling air intakes and exhausts.
I also believe most Navy flying boats had an APU as you couldn't roll up a GPU.
B727 had a turbine APU but it was for ground use only. B707 and DC-8 had no APU (unless modded as some were) but as an option for international service had provision for stored compressed air (3000 psi) which blew down into a combustor and fed the resulting hot air to the starter on No. 3 engine. Always danger of a hung start when using it.
L188 Electras had no APU. Eastern Air Lines however modded one with a turbine APU. It proved to be too noisy in the cabin and was removed.
If memory serves, I also believe the prototype DC-4 with the triple tail had an APU fitted. It certaily would have been a piston powered one.
Last edited by tonytales; 1st June 2012 at 04:36.