10.02.2009, 08:54
viewtopic.php?t=11419
Low pitch or fine pitch\high rpm = max horsepower and manifold pressure but also maximum wear and tear on the powerplant. To reduce these effects after takeoff the rpm,s are reduced by adding more blade angle to the propeller and the manifold pressure is reduced by slightly closing the throttle. This is standard procedure when using an aircraft to get from point A to point B. Most flight manuals will give you a throttle and prop setting for both climb and cruise. Under ACM you should probably have your prop at the high rpm setting so you can pull max horsepower when jockeying the throttle. Mixture is used to acheive higher effeciency as you climb in altitude since a slightly leaner mixture will develop more power but as you lean the cylinder head temps start to climb so this is normally monitored as you reduce your mixture. Whenever you are at full throttle you should probably be at full rich or autorich as the additional fuel helps to cool the cylinder heads. On some WWII aircraft is was also necessary to shift your blower into high as you passed through a certain altitude as this also controls your manifold pressure. Feathering turns the prop blade in the direction of flight and is used to minimize the drag of a dead engine. In a normal configuration the prop blades would be large airbrakes on the front of the aircraft when the prop is not turning.
I guess the answer would be stay in the 8 to 10 range. Personally I mapped the pitch change functions to my left and right mouse buttons. Put it at 10 for takeoff. Pull the prop back to 9 for climbout and back to eight for cruise. I think under combat I would probably just leave it at the high rpm setting. Thats where you are going to pull the most hp out of the power plant and acheive your best rate of climb. The 51 in the game will give a 1500 rpm drop at max manifold pressure which is probably a bit high. Probably should be 600 to 800 rpm. I would need to go look at the TO to see what drop should be at max manifold pressure. You can see by the figures below you are normally working in a 700 RPM range depending on what youre doing with the aircraft.
This is from startup checklist for the 51.
BEFORE TAKE-OFF (Run-Up)
At 2000 RPM, check the following: Suction 3.75 to 4.25 inches HG.
Hydraulic pressure 800-1100 lbs/sq. inch.
Ammeter not to exceed 50 amps.
Check the instruments for the following limitations: Desired Maximum
Oil Pressure 70-80 lbs/sq. in. 90 lbs/sq. in.
Oil Temperature 70 deg C - 80 deg C 90 deg C
Coolant Temperature 100 deg C - 110 deg C 121 deg C
Fuel Pressure 12-16 lbs/sq. in. 19 lbs/sq. in.
Check mags at 2300 RPM. Maximum drop 100 RPM.
At 2300 check propeller - 300 RPM maximum drop - and return to full INCREASE RPM.
Oil and coolant shutters AUTOMATIC.
Wing flaps 20
Low pitch or fine pitch\high rpm = max horsepower and manifold pressure but also maximum wear and tear on the powerplant. To reduce these effects after takeoff the rpm,s are reduced by adding more blade angle to the propeller and the manifold pressure is reduced by slightly closing the throttle. This is standard procedure when using an aircraft to get from point A to point B. Most flight manuals will give you a throttle and prop setting for both climb and cruise. Under ACM you should probably have your prop at the high rpm setting so you can pull max horsepower when jockeying the throttle. Mixture is used to acheive higher effeciency as you climb in altitude since a slightly leaner mixture will develop more power but as you lean the cylinder head temps start to climb so this is normally monitored as you reduce your mixture. Whenever you are at full throttle you should probably be at full rich or autorich as the additional fuel helps to cool the cylinder heads. On some WWII aircraft is was also necessary to shift your blower into high as you passed through a certain altitude as this also controls your manifold pressure. Feathering turns the prop blade in the direction of flight and is used to minimize the drag of a dead engine. In a normal configuration the prop blades would be large airbrakes on the front of the aircraft when the prop is not turning.
I guess the answer would be stay in the 8 to 10 range. Personally I mapped the pitch change functions to my left and right mouse buttons. Put it at 10 for takeoff. Pull the prop back to 9 for climbout and back to eight for cruise. I think under combat I would probably just leave it at the high rpm setting. Thats where you are going to pull the most hp out of the power plant and acheive your best rate of climb. The 51 in the game will give a 1500 rpm drop at max manifold pressure which is probably a bit high. Probably should be 600 to 800 rpm. I would need to go look at the TO to see what drop should be at max manifold pressure. You can see by the figures below you are normally working in a 700 RPM range depending on what youre doing with the aircraft.
This is from startup checklist for the 51.
BEFORE TAKE-OFF (Run-Up)
At 2000 RPM, check the following: Suction 3.75 to 4.25 inches HG.
Hydraulic pressure 800-1100 lbs/sq. inch.
Ammeter not to exceed 50 amps.
Check the instruments for the following limitations: Desired Maximum
Oil Pressure 70-80 lbs/sq. in. 90 lbs/sq. in.
Oil Temperature 70 deg C - 80 deg C 90 deg C
Coolant Temperature 100 deg C - 110 deg C 121 deg C
Fuel Pressure 12-16 lbs/sq. in. 19 lbs/sq. in.
Check mags at 2300 RPM. Maximum drop 100 RPM.
At 2300 check propeller - 300 RPM maximum drop - and return to full INCREASE RPM.
Oil and coolant shutters AUTOMATIC.
Wing flaps 20