Post Tue Feb 18, 2014 1:46 am

Manifold Pressures for R-2800-8 & R-2800-8W

I was just flying some QMB missions. I had expert mode enabled in JSGME. I was flying the F4U-1 when I noticed that the manifold pressures were off. I tested the F4U-1A and F4U-1D. Results were the same in all three aircraft.

When climbing with Normal Power Settings of 44" MAP & 2550 RPM the MAP did not drop as I increased my altitude. When I switched the supercharger at approximately 7,000 feet and increased the MAP to 49.5" MAP the MAP did not drop as I increased my altitude. When I switched the supercharger at approximately 19,000 feet and maintained 49.5" MAP the the MAP did not drop as I increased my altitude. I should have had to keep advancing the throttle to maintain the desired MAP as I climbed (increased my altitude) until I hit full throttle (100%) whereby I would have to switch to a higher supercharger setting. I was actually at 98 - 100% throttle the entire time I climbed.

The next thing I notices was that since I was at or close to 100% throttle most of the time to maintain the desired MAP while climbing that I could not set any military power settings. If I tried to set a military power setting the water injection would engage.

Normal Rated (Max. Continuous) Power depending upon the altitude is 44" or 49.5" MAP at 2550 RPM
Military Power depending upon the altitude is 52.5" or 53.0" MAP at 2700 RPM

If I tried to advance the throttle past 49.5" MAP the MAP would jump to 57.0" or 59.0" or 59.5" depending upon the altitude and engage Water Injection which is War Emergency Power. Military Power does not exist in Expert Mode. It is either Normal Rated or War Emergency.

If I turn off the Expert Mode in the JSGME then the manifold pressures are as they should be right off the pages of the Specific Engine Flight Charts of the R-2800-8 and R-2800-8W for the F4U-1, FG-1, F3A-1.

References:
1. Pilot's Handbook of Flight Operating Instructions For Naval Models F4U-1 F4U-1C F4U-1D F3A-1 F3A-1D FG-1 FG-1D Airplanes British Models Corsair I.II.III.IV
2. Pilote's Notes Corsair I-IV Double Wasp R2800-8 or R2800-8W Engine
3. Pilots Manual For the F4U Corsair (looks like a reprint of the first reference above, but a specific engine chart for the R-2800-8)

-)-MAILMAN-