Lauson "B29 starting engine"

[krswen]

Years ago I was given a little rootes supercharger (which was damaged and I no longer have) and it was described as being from "a B-29 starting engine". Was this in fact a supercharged piston engine apu? Was something similar also used on the Boeing B377 Stratocruiser? That would explain how the engine could be run at up to 20,000 ft. Otherwise I can't imagine even starting a piston engine at that altitude.

krswen

[John Hanson]

Both of those planes had electric start engines. The '29 ran a 3350 Wright and the Strat ran a 4360 Pratt. They both use an electric start. What that person was most likely referring to was the APU that could supply aux power on the ground or in flight if need be. That was a small gas engine that was located further aft in the fuselage, connected to a generator.
The 3350's are turbo-compounded in that application, so maybe that's what you had? Both engines are supercharged as well.
John

[Robert Haus]

It was probably from a ground power unit...the R-3350's and the R-4360's had centrifugal blowers....the later 3350's also had the turbo compounding (this would have been found in the Constellations and some transports of the 1950's....the ww2 B-29's were not turbocompounded but did have turbosuperchargers.)

fyi, the turbo compound R-3350 and the R-4360 were the biggest successful recips and were pretty much the end of the line for the technology...Pratt and Whitney dropped the R-4360 and went on to jets.....Curtiss-Wright stuck it out with the 3350, adding the turbo-compounding and other refinements to improve power and SFC.....Pratt and Whitney is still here, Wright had no significant follow on turbine technology and is gone.)

The 3350's were kinda tempermental....especially the early ones.......they used to say that we lost more B-29's to Curtiss-Wright than to the Japanese.

The 4360's went into Hughes' Spruce Goose, the B-36, the 377, KC-97's and a few others......the post war uses of the 3350 include the Constellation, AD-1 Skyraider, and a few other transports (C-119, etc) today both the 3350's and the 4360's can be found in some of the Reno Air Racers.