View Full Version : Prop Pitch

12-07-2004, 03:57 PM
Can someone explain or give me a link for some good information on how it works, how to use it and why to use it. At the moment im just using auto flying the seafire


12-07-2004, 04:18 PM
You'll probably get more than you wanted...

With the pitch at 100%, or "fine", the prop is taking a thinner slice of the air with each revolution. Think of it as low gear. Max pulling power at lower altitudes, where the atmosphere is relatively thick.

As you gain altitude, you can decrease the pitch, (or "coarse", as the Brits say) to take progressively bigger slices of the progressively thinner air.
This means, usually, lower engine RPM, and thus less engine heating and better fuel economy.

Many WWII aircraft have auto-pitch controls, so you don't have to mess with it.
When cruising, you'll want an economical setting that won't strain your engine; look to the PDF manual for suggested cruising RPM, or just keep the tachometer out of the red zone.

Bumping the prop up to 100% and shutting off the throttle acts as a bit of an airbrake when diving from high altitudes.

12-07-2004, 04:24 PM

I will give you the super high level version. The game doesn't really model it perfectly but it's part of the game and it can give you some advantages.

There are two types in the game but they model the fairly close.

The real reason why you have prop control is for cruising and climbing.

A constant speed prop is designed to give you a certain RPM regardless of how much power the engine is producing (Manifold Pressure) measured in inches.

Basically think of the prop as a kind of gear if you will. If you're going up hill you want to put the plane into a lower gear by allowing the prop to run at a higher RPM. As you get to your proper altitude you have the option of gaining more effeciency by reducing RPM. Meaning you're increasing the prop angle or creating a bigger bite out of the air. In doing so the RPM will drop because your putting more load on the engine. The reason for this is to reduce RPM and gain efficiency like a high gear in a car.

As a general rule of thumb you never want to have a low prop RPM while generating high manifold pressure. The other thing to remember in the game is High RPM can blow and engine as well.

I usually set mine after reaching my altitude at about 95 percent which is sort of a compromise between a cruise prop and a climb prop.

That should get you started in the right direction. Look up constant speed prop online I'm sure you can find more info.


12-07-2004, 04:54 PM
Scen has it closest, but the game models 4 (or arguably 6) types of 'prop pitch' systems. The term 'prop pitch' as used in the sim is a generic term, and does not necessarily have anything to do with actual propellor blade angle. Try here http://people.ee.ethz.ch/~chapman/il2guide/cemguide/intro.htm for some good (meaning correct) details.

Please beware of the 'gears in a car' analogy, as it can be extremely misleading (incorrect) for most of the aircraft in the sim. It is usually best to choose one type of aircraft to learn about, as their is just to much information to digest for all of the aircraft at once. Like Scen said, Constant Speed Props are the most common (and the most unlike the gears in a car), you might try a search here or at SimHQ.com forums for more info.

12-08-2004, 11:57 AM
The biggest problem people have understanding how this is modeled in thae game, and how it is supposed to work is the use of the term 'Prop Pitch'. Almost all of the planes of the era used a 'constant speed' prop. What you are doing is setting the prop mechanism to maintain a certain rotational (engine) speed, automaticlly varying the pitch to absorb the power from the engine.

How to use it; 100% RPM (pitch....) for takeoff and combat. Reduce RPM (pitch....) and manifold pressure (throttle) for climb and cruise. Move RPM to max on approach to the boat in case of waveoff.

There were charts provided for the (real) planes to maximize cruise, climb and descent profiles consistant with engine life and performance, we donn'a have those.