An addition/correction to my previous posting. On Sunday 17 July 2005 18:29, Peter Stickney wrote: > On Friday 15 July 2005 06:45, Vivian Meazza wrote: > > 6. Copies of the relevant pages of the Pilot's Manual. Post these > somewhere > > that I can access/fetch. Particularly any description of the > variable boost > > control. > > That was the FE's job. The supercharger system of a B-29, or any > other turbosupercharged airplane worked like this: (Well, was > supposed to work like this - Early B-17s and B-24s with the > mechanical oil pressure driven turboregulators required more > fiddling, but the electronic turboregulators used on later -17s, 24s, > P-38s, P-47s, B-29s and subsequent airplanes did work like this) > > There was a potentiometer dial on the turboregulator control box that > was calibrated from "0" to "10". This selected the amount of output. > from the turbo system as a whole, "0" being no output. The turbos > supplied air to the inlet of the engine's mechanical supercharger at > slightly over sea level ambient (29.92" on a Standard Day). This was > done to keep the turbo moving, so that it didn't freeze up due to > poor lubrication at Sea Level. The engine's throttle was set to > provide whatever power conditions were required, and as the airplane > climbed, the turbo's "Volume Control" was tweaked to keep providing > its sea level conditions to the engine's supercharger. The > Turboregulator governed on the selected pressure rise (The "Volume" > and turbo RPM and, often, bearing temperature. The Pilot of Flight > Engineer had no indication, or control over the turbo except the > potentiometer. As far as the engine was concerned, it was sitting > happily at Sea Level the whole time. Once it had reached the point > where the turbosupercharger/mechanical blow couldn't supply the > proper power conditions any more, power dropped off normally.
As it turns out, the B-29's turboregulator control was a little bit different from what I described. The "Volume Control" governed off total system MAP. If you set the potentiometer to , say, '*8", it maintained the overall MAP until the turbo reached its limits. So, for example, you set the engines to Max Continuous, you wouldn't need to twiddle the turbos as you climbed from Sea Level to 25,000'+. Sorry if I cased some confusion, there. "Zeno's Warbirds" has, IIRC, a Realplayer movie on flying the B-29. That's a pretty good resource. -- Pete Stickney _______________________________________________ Flightgear-devel mailing list [email protected] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
