Prop Pitch question...

[Rama]

Originally Posted by BSS_Sniper

I believe you're just reading stuff on the internet without practical experience.

Well... you're wrong... don't try to guess... just stick on what you know.
I have my pilot license (I'm only a sunday pilot) and I'm an engineer with quite good knowings in fly mechanics

Yes on CSP aircraft, the pitch will change if you change the MP, but only a minute amount. It will NOT make up for large changes in MP.

You didn't read or understood what I said.... well... it's not a big problem.

A good example is at idle. Although I have my prop lever at full, I will still idle at about 700 rpm. The same goes if I am at a lower RPM and shove my throttle up to max MP, it will damage the engine because the prop governor will try to keep the RPM's constant, but the MP pushing the engine to its limits or past.

I totally agree with that. It doesn't contradict what I said.
Like I said, in this case you will overtorque the engine.

I have tested over and over for extended periods in game. I will take, for example, a P51 run it at full throttle and drop my PP to 50% and run all day without damage. That is what I'm talking about.

Now try at full throttle and 0% PP... you will see (I'm not 100% sure for the P51, but for other planes I experienced in game engine heating and breakdown after a few minutes)

So In game overtorque IS modelled, but not reastically, the game is too tolerant (and even more for overreving)
... as I said in previous post.

[BSS_Sniper]

Originally Posted by Rama

Well... you're wrong... don't try to guess... just stick on what you know.
I have my pilot license (I'm only a sunday pilot) and I'm an engineer with quite good knowings in fly mechanics


You didn't read or understood what I said.... well... it's not a big problem.


I totally agree with that. It doesn't contradict what I said.
Like I said, in this case you will overtorque the engine.


Now try at full throttle and 0% PP... you will see (I'm not 100% sure for the P51, but for other planes I experienced in game engine heating and breakdown after a few minutes)

So In game overtorque IS modelled, but not reastically, the game is too tolerant (and even more for overreving)
... as I said in previous post.

Respectfully, you being an engineer has zero bearing on your weekend knowledge of being an amature pilot. For the sake of simplicity, the pitch angle does not change with throttle changes. I'll see if I can get some other professional pilots in here. My dad just shakes his head at this. He recalls the worst pilots he ever flew with were the ones that were too "book smart". There's more to flying than by the book, you gotta feel it and live it. If you can't get past all the technical/books you'll be confined in a box.

The game is exceptionally tolerant to anything concerning CEM to the point of being arcadish.

[Rama]

Despite you saying "respectfully", you don't show much respect... no problems... if you feel superior, that's your problem.
It's just making a difference with all the pro pilots I know... all very nice guys.
... and you obviously you have a problem with understanding CSP mecahnical fonctionning and CS governor...
CS governor controls pitch angle and adjust it to keep RPM constant. that's why when you adjust throttle pitch do change (adjusted by CSP to keep RPM constant).
not much knowing is needed to understand that... look there for example: http://www.pilotfriend.com/training/...wing/props.htm

[Vidar_710]

Maybe this will clear things up. Let's keep it simple.

Throttle Levers control power and RPM from idol up to Flight power settings.
Prop Levers control and refine RPM and Prop Pitch.
Mixture Leverscontrol fuel flow.

*NOTE: Throttle does NOT have any input to prop pitch settings what-so-ever.

The reason for Constant Speed/Variable Pitch propellors is to Optimize the pitch of the propellor in conjuction with power -i.e.throttle- settings at various stages of flight.

High RPM/Low pitch with Hi power setting for take-offs.
Med-Hi RPM/Low Pitch with Medium Power setting for climb-outs.
Medium RPM/Medium Pitch with Medium Power setting for Cruise flight.
High RPM/Low pitch with Low power setting for final stage -i.e. last few hundred feet- before landing. WHY you ask?

1. The flat-low pitch helps slow the plane down.
2. The Low pitch/Hi RPM is readily available without danger of overspeeding via manifold presure inputs from the throttle for Go-Arounds proceedures.

Keep in mind...
Medium - Hi Power settings may only be a difference of 2" of Manifold Pressure, and Medium to Hi RPM may only range 200-300 RPM from max power back down to Cruise flight.

Depending on the power plant, there are specific limits to manifold pressure to specific RPM settings. You never want to put manifold pressure past the specified RPM setting.

Everything Mr Sniper has said is completley correct.



V

[comswim]

I can sorta see what your getting at there Rama, but I too would have to agree with Vidar and Sniper on this too. My question is will it be different when BoB comes out.

S!

Comswim

[BSS_Sniper]

Originally Posted by comswim

I can sorta see what your getting at there Rama, but I too would have to agree with Vidar and Sniper on this too. My question is will it be different when BoB comes out.

S!

Comswim

We can only hope and pray.

[Rama]

Actually... nothing Vidar said actually contradict what I said, except the last sentence.

He even sais in another form what I said:

The reason for Constant Speed/Variable Pitch propellors is to Optimize the pitch of the propellor in conjuction with power -i.e.throttle- settings at various stages of flight.

CSP do control pitch and do it constantly to adjust for RPM... I said nothing different.
So for a fixed position of the RPM Lever, then, inside the CS Propellor limits:
- if you increase boost (admission pressure): CSP will adjust pitch and blade angle will increase to keep RPM constant.
- if you decrease boost (admission pressure): CSP will adjust pitch and blade angle will decrease to keep RPM constant.
- If you pull the stick, speed will go down: CSP will adjust pitch and blade angle will increase to keep RPM constant (up you reach the limit of the CSP, then RPM will decrease, and you will risk overtorque if you did set RPM too low)
- If you push the stick, speed will increase: CSP will adjust pitch and blade angle will decrease to keep RPM constant (until you reach the limit of the CSP, then RPM will increase and you'll risk overreving if you did set the RPM lever too high)

I did try to stay as simple as possible to be sure to be understood (since I begin to think my English is so bad that Sniper and Vidar don't understand it.... then I should go to take some English lessons...)

[BSS_Sniper]

Rama, I apologize. I just tend to get excited when I know I'm right about something, especially if someone blatantly says I'm wrong about something that is my profession. I doubt you tell your professional pilot friends "You are wrong" when they correct you on something. No harm intended though. Vidar stated things more clear than I was able to.

I did talk to our company A&P. (airframe and powerplant mechanic) The one time the pitch changes without input of the prop levers is if you go into a dive. The change is, however, so brief that it is not something noticed and only a technical note. It would have to be something extreme so that the relative wind is driving the prop and not the engine. The RPM's will speed up a bit and only VERY briefly. That will change the prop pitch, but the governor will bring them back to what the pilot set them at. It's just a brief second or two of change, nothing that would be noticed normally by the pilot.

So in the end, the throttle (Manifold Pressure) will not change Prop Pitch.