[Aurora]

What exactly is it for? How do I benefit from Prop. Pitch?

[Russ_Ace]

Prop pich is the width or direction of the blades on the prpeller, i set at auto since there arnt enof buttons on my keybord.

[.041 Safety Wire]

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

[-)-MAILMAN-]

In a nut shell it is the angle of the propeller blade as it cuts through the air.

.041 Safety Wire gave you some setting regarding the P-51.

Some planes had manual pitch control and had to manually change the pitch settings of the propeller to match the power/throttle settings for a particular operation and altitude.

Other planes had the prop pitch controlled automatically. Most US aircraft used automatic propeller control. The pilot would set the RPM of the propeller of to a certain speed based on the type of power setting it was using:

War Emergency Power
Military Power
Normal Power
Cruise

The automatic propeller control would keep the RPM constant (when the aircraft was fitted with a constant speed propeller). When the throttle was advanced or retarded the RPM would change initially, but the propeller blade pitch would automatically change to bring the propeller RPM back the setting the pilot had set. The F4U Corsair and F6F Hellcat used the following:

War Emergency Power = 2700RPM

Military Power = 2700 RPM

Normal Power = 2550 RPM @ 44" MAP below 8,000 Feet, Neutral Blower (Super Charger 1 in game), 48" MAP 8,000 Ft, Low Blower (Super Charger 2 in game), 48" MAP @ 15,000 FT High Blower (Super Charger 3 @ approximately 18.000 ft in game). You can tell when to switch super charger settings because given the set RPM you have to advance your throttle beyond 100% to maintain the MAP at a given altitude and Super Charger setting.

Hope this helps explain it a bit. Will keep the temperature down so you are not close to overheating when you enter combat in the game. May mean the difference of egressing or burning up your motor before egressing.

[Aurora]

Ok thanks for your help!

[boogabooga]

I wrote this some time ago:

http://www.mission4today.com/index.php? ... ow&kid=457

Bottom line is lowering the RPM gives you better endurance. Same reason you don't drive your car in first gear on the highway at 60mph and 5000 rpm.

But don't take real world data and expect it to work in IL-2. AFAIK, in IL-2 world, 75% RPM is cruise and 70% econo cruise for just about everything.

[BillSwagger]

Also i noticed you get more speed from a plane using prop pitch other than at full throttle.

You can see this when you try to wing up with AI.

I find that with some planes i can pace the AI at about 55/100 ( throttle/prop pitch ).

If i lower prop pitch to 70 I will out pace the AI.

It depends on the plane, but 55/100 runs at the same speed as 45/70, which overall means you are saving fuel and not losing any speed.

I'd have to think that running at 80/100 also has a more efficient setting, but i haven't taken the time to find it.


Bill.

[RAAF Steppie]

most of the aircraft( some German aircraft change from auto or manual) in IL2 you have no direct control over the propeller pitch. It call a constant speed propeller and it mean the when you adjust the pitch in the game you are setting the rpm you want the engine to run at the the propeller become the governor. this is to take the work load of the pilots also it mean you have the engine run at it best power setting with out over reving.
so the best advise i can give you about propeller setting is to forget them, leave it at 100% as this is were the engine give the most horse power. The only time i will change it is if i get damage to the engine and then i will lower the RPM setting to make it last long before it quits.

If you have ever watch a video and seen pilot rev there motor before taking of what they are checking for is one the magneto and checking to see if the CSP are working properly and not running away.