Prop pitch and how its modeled in AH

[Bosco123]

To put it simple:
There is a very fine line between to much pitch, and not enough blade. The best is when you can get the blade and the pitch about at the same level, so you can get the maximum engine preformance. My perfect example:
Last week we were testing a 24 inch blade on a friend of mines Zero. Not knowing it, he had 0 pitch and I was soley flying it on the wing. This week, we put on a 22 inch with 10 pitch (22X10) 2 blade and incersed the power preformance by probably 100 times from last week.

Hope that helps.

<S>

[bozon]

Feathered props are modeled only on multi-engined planes. It is easy to check in-flight: turn off your engine. The prop will auto-feather and stop rotating if it can. You will notice that on all single engine planes the prop will keep wind-milling.

Reducing RPM in glide makes a huge difference. A plane like the mosquito that has very little drag for its mass and feathered props is quite hard to land when the engines are off. You have to use rudder or lots of flaps to bleed speed and bring it down.

I once tested RPM effects on high-speed dive acceleration with P-47 and Mosquito. Couldn't find a difference within my measurement accuracy. Also tried to see if it affects speed bleed when the speed is well over your max level speed (after a dive). Again, found no clear advantage to reducing RPM in this situation. Therefore I don't really know how the FM handles this other side of the envelope. If someone can re-do such tests, I would be interested to hear the results. An easy thing to test that may give us a hint is to reduce throttle to min and make a dive to high speed - check how high the RPM gets - it will not over-rev, but does it stay constant even at very high speeds or does it peg at the usual max RPM limit? None is exactly correct, but may give us a hint of how it is modeled.

[Ardy123]

Feathered props are modeled only on multi-engined planes. It is easy to check in-flight: turn off your engine. The prop will auto-feather and stop rotating if it can. You will notice that on all single engine planes the prop will keep wind-milling.

Reducing RPM in glide makes a huge difference. A plane like the mosquito that has very little drag for its mass and feathered props is quite hard to land when the engines are off. You have to use rudder or lots of flaps to bleed speed and bring it down.

I once tested RPM effects on high-speed dive acceleration with P-47 and Mosquito. Couldn't find a difference within my measurement accuracy. Also tried to see if it affects speed bleed when the speed is well over your max level speed (after a dive). Again, found no clear advantage to reducing RPM in this situation. Therefore I don't really know how the FM handles this other side of the envelope. If someone can re-do such tests, I would be interested to hear the results. An easy thing to test that may give us a hint is to reduce throttle to min and make a dive to high speed - check how high the RPM gets - it will not over-rev, but does it stay constant even at very high speeds or does it peg at the usual max RPM limit? None is exactly correct, but may give us a hint of how it is modeled.

I did a simple test with a 109 g14 and found the following...

1) I dove from high alt and reduced RPMs to the lowest I could, which was around 15,000 and not much happened, the RPMs did not go up. Now I did pull up after going about ~500mph. I would have expected the RPMs to go up just from the reduced 'load' on the engine.

2) I flew the airplane at a level max speed, no wep, at 10k  which was around ~350 and then reduced RPMs to encourage the prop to take a 'bigger bite' out of each rotation, but all that happened was my fuel consumption went down and my speed reduced to about ~300. I would have expected some 'medium mix' where max RPM didn't mean max speed, just like running your car in first gear with the RPMs red-lined is not full speed.

3) I could not feather the prop, prop always spun, even with engine off. This is in line with a previous post about prop-feathering only working on multi-engined planes.

[Traveler]

NOTE- not every plane model has the feathered prop capability, but all plane models have the ability to control the RPM


Traveler, if memory serves me right, if your engine seizes up from being damaged then you cannot feather the prop in game, if infact that particular aircraft had feathered prop ability or not.

on the other hand, if you begin to run low on fuel and or want to conserve, you can feather the prop ( if that particular aircraft had feathered prop ability ) by reducing the RPM as long as the blade is still turning........regardless if the engine is running or has been shutdown......

If the plane does not have feathered prop capability then the prop will not freespin when the engine is dead, but reducing the RPM then shutting down the engine will give you a little benefit if trying to glide back to base.....

sorry, but I would have to log in and recheck my memory by doing a test to say this is 100% accurate.....

but this is what/how I remember this feature working in Aces High II

also remember the differences in the Keyboard keys and the numberpad keys:

Keyboard keys control the Throttle:
- for Reducing
= for Increasing

Numberpad keys control the RPM:
- for Reducing
+ for Increasing

as for how it looks or appears in game or pictures, from my recollection the Propeller is graphically coded as one piece, but the mechanical effects are still there, just not viewable ( YET anyhow )


hope this helps  ( please correct my post, if I misrepresented anything pertaining to how RPM & Prop pitch works in Aces High, I did not bother with verification )

I agree with you that the effect of feathering may be coded into the  game even if it can’t be seen in the graphic of the prop. 

I took a P38G, J and L for my testing,  According to documents online that I found  all three models had feathering props and I am assuming that the effects of feathered props are modeled into the game.

One tidbit that I noticed is that the game for most of us provides the ability to perform operations on a selected engine by first pressing the Shift key and the number 1 or 2 to select either the left or right engine.  Once you select an engine, any change in manifold pressure only effects the engine selected, however, any change to the Prop (RPM) control appears to effect both engines.  That according to the visual display of the RPM gauge in the cockpit.  That must be a bug because it would appear that only the RPM on the selected engine was being reduced.  Once the engine was shut down using the E key and control changed to the working engine, changes to the Manifold and Prop controls are only reflected on that engines gague.

[Ack-Ack]

I took a P38G, J and L for my testing,  According to documents online that I found  all three models had feathering props and I am assuming that the effects of feathered props are modeled into the game.

IIRC, it's automatic in the P-38 in game.  If you run out of fuel it automatically feathers the props.


ack-ack

[FLS]

I agree with you that the effect of feathering may be coded into the  game even if it can’t be seen in the graphic of the prop. 

I took a P38G, J and L for my testing,  According to documents online that I found  all three models had feathering props and I am assuming that the effects of feathered props are modeled into the game.

One tidbit that I noticed is that the game for most of us provides the ability to perform operations on a selected engine by first pressing the Shift key and the number 1 or 2 to select either the left or right engine.  Once you select an engine, any change in manifold pressure only effects the engine selected, however, any change to the Prop (RPM) control appears to effect both engines.  That according to the visual display of the RPM gauge in the cockpit.  That must be a bug because it would appear that only the RPM on the selected engine was being reduced.  Once the engine was shut down using the E key and control changed to the working engine, changes to the Manifold and Prop controls are only reflected on that engines gague.

The keypad RPM is global for all engines. If you select RPM1 for an axis control it's global for all engines. If you select RPM 1-4 for different axis then you have individual RPM control. Engine selection appears to be separate from prop selection.

[Traveler]

The keypad RPM is global for all engines. If you select RPM1 for an axis control it's global for all engines. If you select RPM 1-4 for different axis then you have individual RPM control. Engine selection appears to be separate from prop selection.

How and where do you make that selection.  I did not see an RPM 1-4 in the control mapper.  If you mean in the game, you can't select RPM, you can only select an engine 1-4 , if you select Engine 1 by hitting Shift + 1 key, and you reduce RPM using the keypad  - key, you will see in the cockpit RPM gage that both Engine 1 and 2 RPM is reduced.

[bj229r]

Just so there's no more asking for an answer..


YES DEAR GOD YES IT'S MODELED!!!


Okay, now that that's outta the way.... back to your regular programming.

Well.....unless you have an early Hurricane

[Ack-Ack]

How and where do you make that selection.  I did not see an RPM 1-4 in the control mapper.  If you mean in the game, you can't select RPM, you can only select an engine 1-4 , if you select Engine 1 by hitting Shift + 1 key, and you reduce RPM using the keypad  - key, you will see in the cockpit RPM gage that both Engine 1 and 2 RPM is reduced.

You need to select the engine you want to adjust the trim for.  IIRC, commands are Shift+1, Shift+2, Shift+3, and Shift+4.  Shift+E selects all engines.

[CAP1]

I read your post, I was asking if it was actually modeled.. like in AH you can reduce your RPMs to feather it but DOES IT ACTUALLY MAKE A DIFFERENCE in AH, not if you could do it.

i believe all twin engine planes auto-feather when shut down. i think you have to manually feather single engine props.

[bozon]

1) I dove from high alt and reduced RPMs to the lowest I could, which was around 15,000 and not much happened, the RPMs did not go up. Now I did pull up after going about ~500mph. I would have expected the RPMs to go up just from the reduced 'load' on the engine.

This suggests that the prop pitch is unrestricted if auto adjusted to maintain RPM.

[MutleyBR]

Correct that RPM value.

Prop RPM indicators are in thousands, not 10000's.
Thus, 1500 RPM.

Mutley

[Ardy123]

Correct that RPM value.

Prop RPM indicators are in thousands, not 10000's.
Thus, 1500 RPM.

Mutley

yup, your right, these aren't model aircraft. 15,000 rpm would have super-sonic tips, rendering the propellers useless. I did notice that on the g14 that reducing the rpms as much as possible did have a dramatic improvement on glide performance.

[Krusty]

Well.....unless you have an early Hurricane

Which isn't in this game


Back on topic: Reducing RPM is night and day when you're gliding. The prop is a giant speed brake and will slow you down horribly when you have no power to spin it. By reducing the RPM you reduce drag by massive amounts. You can gain over 500fpm alt loss by gliding at full RPM, as compared to gliding with minimum RPM.

Try it. It's a practical application in-game that will save you more times than now. I've glided down to the end of a runway and barely made it with low RPMs soooo many times. If I had left RPMs at full I would have ditched halfway there too many times to count.

EDIT: P.S. Also leave RPM at full and chop throttle if you want to slow down in steep dives. If you want to accelerate in steep dives... well leave the throttle on! nyuck nyuck!

[MutleyBR]

...reducing the rpms as much as possible did have a dramatic improvement on glide performance.

Here´s an AH film, rather long but shows how far one can go by reducing RPM  for gliding.

Was in a Dora, w/ 1x500kg egg for GV attack. Dived on the field and saw no GV just passing rwy end noticed B-24 formation upping....
Dived back and dropped the egg on the formation...
Being the ack magnet I am, got both fuel tanks and RH gear hit by ack.
Had to RTB and belly land.
Climbed as much as I could. When engine quit due to fuel starvation, reduced RPM and glided back home.
Doing so, arrived too high for landing.
On approach, increased RPM to increase drag.
Landed  and bagged those 2 kills.

Mutley

Effect of RPM in glides:

http://www.mediafire.com/file/nyqbmzyibof/RPM and glide.ahf