BF-109 Prop Pitch Lever

[gpang788]

What about in a dogfight? Do you go 12 all the way?

Notice its really easy to fry the engine if you go 12 in combat.

[Blackdog_kt]

It's like shifting gears in a car.

high rpm = low gears
low rpm = high gears
driving uphill = climbing
driving downhill = diving


In that sense, if i want to pick up speed in a dive i'll do what i do in a car to accelerate when driving downhill: step on the gas pedal and shift to a higher gear = increase throttle and decrease RPM

However, if i want to make sure i don't go too fast in the dive i'll do what i do in a car if i want to go slower: let go of the gas pedal, shift to a lower gear and let it act as a brake as the car rolls downhill = pull the throttle back and set pitch for increased RPM

In other words, if you want to get good performance in a dogfight you'll have to keep changing the prop pitch all the time. Otherwise you might get poor acceleration in a dive or reduced climb rate and it can get you killed.

Hope it helps.

[badfinger]

Originally Posted by Blackdog_kt

It's like shifting gears in a car.

high rpm = low gears
low rpm = high gears
driving uphill = climbing
driving downhill = diving


In that sense, if i want to pick up speed in a dive i'll do what i do in a car to accelerate when driving downhill: step on the gas pedal and shift to a higher gear = increase throttle and decrease RPM

However, if i want to make sure i don't go too fast in the dive i'll do what i do in a car if i want to go slower: let go of the gas pedal, shift to a lower gear and let it act as a brake as the car rolls downhill = pull the throttle back and set pitch for increased RPM

In other words, if you want to get good performance in a dogfight you'll have to keep changing the prop pitch all the time. Otherwise you might get poor acceleration in a dive or reduced climb rate and it can get you killed.

Hope it helps.

I have always had problems flying formation, going too fast or too slow, and I am now wondering if maybe the secret is to adjust the prop pitch, instead of the throttle. Using the prop as a brake and to make small adjustments in speed.

Does that sound right to anyone? If not, what is the secret to staying in formation?

binky9

[VO101_Tom]

Originally Posted by binky9

I have always had problems flying formation, going too fast or too slow, and I am now wondering if maybe the secret is to adjust the prop pitch, instead of the throttle. Using the prop as a brake and to make small adjustments in speed.

Does that sound right to anyone? If not, what is the secret to staying in formation?

binky9

No. The function of prop-pitch to keep the engine rpm in its limits. Anyway, the accelerating - decelerating effect much slower, than engine throttle.

Stay calm in formation flying. Move the stick and the throttle gently, and wait for its effect (and give a thought to it, that what you do, the effect will be little late).

[Blackdog_kt]

Originally Posted by binky9

I have always had problems flying formation, going too fast or too slow, and I am now wondering if maybe the secret is to adjust the prop pitch, instead of the throttle. Using the prop as a brake and to make small adjustments in speed.

Does that sound right to anyone? If not, what is the secret to staying in formation?

binky9

Like i said before, pitch is like car gears. To stay in formation easier you need a more responsive gear = slightly higher RPM. This gives you a better braking effect when you pull the throttle back (because at finer pitch the prop blades are more in a "face on" alignment to the incoming airflow and act as windmills creating resistance if the engine isn't turning the prop fast enough on its own), but also a better acceleration when you do apply throttle.

Historically, wingmen always used to end up burning more fuel than leaders because of this. The leader would just select his power settings and keep them steady, but the wingmen used slightly higher RPM and played around with the the throttle to stay in formation.

What i like to do in manual pitch aircraft like the 109 is to approach the leader by applying the right combination of throttle and pitch and then forget about pitch altogether. Essentially it's like i'm flying with a fixed pitch prop at this point (much like a tiger moth) and i do all my acceleration/deceleration with the throttle.

To use the car analogy, it's like trying to drive side by side to an identical car doing 140km/h on 5th gear (formation is straight and level flight mostly, so in the car analogy it's like driving on a uniformly flat piece of road). I use 4th gear to get more "pull" and pull up alongside him, then i keep the gear there and just release pressure or apply more of it on the gas pedal to make sure i stay into position.

If i use 6th gear i'll save more fuel, but every change i make in the amount of gas pedal deflection (no matter if it's adding or reducing power) will take a longer time to take effect.

[ATAG_Doc]

I love the way blackdog explains things. He's very helpful and clear.

[fireship4]

I think 2500 might be too high for any significant amount of time. In Flea's datasheets you find the following for the e3 (of course I don't know how much of this is appropriate to CoD).

Situation_ATA___RPM__Time
Takeoff___1.45___2468___5min
Climb____1.35___2368___30min
Cruise___1.30___2326___Cons.
Dive_____Idle___3000____-

[VF-51_hawg]

Originally Posted by gpang788

What about in a dogfight? Do you go 12 all the way?

Notice its really easy to fry the engine if you go 12 in combat.

I noticed the same thing, I believe that you cant exceed 3000 RPM for more than 30 seconds or you'll pop the engine. I think there is some user made documentation some place that may cover this.

EDIT....I may have spoke too soon. I went poking through the manual and look what I found.

Never exceed 3,000 rpm.
Trim slightly nose-heavy.
Chop throttle to 0.
Prop around 09:30.
Water flap half-open to fully closed in any weather.
Oil and water temperature: never below 40 degrees
IL2CoD

[Hans]

Try to keep the revs around 2300 rpm (ain't that easy in a dogfight).
3000 rpm is absolutely hazardous. You shouldn't exceed 2500 rpm at all, if you want to bring the kite back to home base across the Channel.