P-38 Rpm

[FLS]

The big RPM drop in game happens when there is a load perpendicular to the thrust.

[hitech]

The big RPM drop in game happens when there is a load perpendicular to the thrust.

Can you explain? I am not sure what you mean.

[FLS]

Pulling up or pushing down quickly will drop the RPM. Snap rolling a P-38 will drop the RPM as the engines describe a circle.  The reason I thought it was affecting the vertical snap roll departures is because that's when I noticed the quick drop in RPM. I'm guess a side load on the prop but I don't know how it's modeled.

[colmbo]

I was playing around with it...pull hard into buffet and the RPM drops 4-500 RPM with some fluctuation.  That is a huge RPM drop.  Now if I could get my hands on a P-38 to go out and test this.....

[38ruk]

I was wondering if the RPM drop of 4-500 rpm during hard maneuvers is why i am see a difference in performance between AH2 and 3.  The plane seems more unstable ( easier to stall and harder to pull threw maneuvers like in AH2) .... I'm guessing the 4-500 rpm drop causes a lack of power compared to the steady 3000 rpm that Ah2 had modeled ?  I could be totally off base so that why this should be looked at as a question and not a statement .

Also .... from the deck to 5k or so the 38 will run at a full 3000 rpm , up higher it stays at 2900rpm unless you dive , in a dive ive seen 3100 max.  Thanks for the info.

[hitech]

It's so to speed change not the load

[FLS]

It's due to speed change not the load.

Now it seems so obvious.   

Is there a drop in thrust when the RPM drops?

... The plane seems more unstable ( easier to stall and harder to pull through maneuvers like in AH2) ....

38ruk a few people have posted about stalling more and I suspect the new stall buffet sound is a factor. If you are listening for the old sound you will stall before you hear it. You can still see the cockpit shake but you may be looking elsewhere in a fight. Pull to the buffet and get acquainted with the new sound if you haven't already.

[hitech]

Btw after thinking about this last night I will be making a change. Right now the RPM change is linear with  speed change (I.E. Acceleration Deceleration). After giving it some thought the system would be acting faster the further you are from set point. I.E. Valve open more as distance from set point is increased.

This has the effect of making the change exponential instead of linear. Net result will be the small changes you hear will be the about the same, but it will not continue to increase so drastically as you increase to hard maneuvering.

HiTech

 

[colmbo]

Thank you

[GScholz]

Sounds good. The electrically actuated props like on the P-38 and 109 were on/off deals, no gradual movement, but there would still be a slight lag as the system must detect an rpm change then activate the electric motor.

[GScholz]

[GScholz]

Also in the 109 (F series onward) the throttle and RPM were linked to one control. I.e. the throttle lever would adjust both throttle and RPM. So moving the throttle back to cruise setting would also lower the RPM to cruise, full throttle would set the RPM to max etc.

[38ruk]

Now it seems so obvious.   

Is there a drop in thrust when the RPM drops?

38ruk a few people have posted about stalling more and I suspect the new stall buffet sound is a factor. If you are listening for the old sound you will stall before you hear it. You can still see the cockpit shake but you may be looking elsewhere in a fight. Pull to the buffet and get acquainted with the new sound if you haven't already.

FLS ,  I was an  alpha and beta tester so the sound isn't really new to me .  That said , It was hard to find fights in the alpha /and early beta so i didn't really see the effects of hard maneuvers compared to and E/A pulling the same moves to counter mine . 

My biggest complaint is I've been flying a 38 since 01 and knowing to a decent degree what i used to be able to do at certain air speeds all of the sudden change when the FM  hasn't changed.  I do appreciate your help and suggestions. I really do , but after all the years of flying it , it's hard to believe that im fluttering out of the sky and basically a sitting duck at speeds that used to able to bring the nose through.  I'm not saying your wrong .....and i'm not saying I'm right .  Just trying to figure out why i cant do things that are like second nature to me in the new version .  <S> and thanks for the constructive conversation . 

Believe me ..... I'm not one to think Im always right , just looking for something i might be doing wrong or possibly there something has changed minutely that is throwing me off. I'd like to think i know the bird pretty well , but there is always more to learn. Thx again and <S> 38

[FLS]

I understand your point. I had a similar experience with stall departures. 

You can compare the stall by matching speed and g load on the accelerometer between AH2 and AH3. Pulling past the stall to departure will let you compare recovery.

I assume you have the same advanced stick settings and calibration.

[38ruk]

Yes on the advantaged stick scaling , dead band and damping.  Calibration was done in AH and Win7 as usual. Thanks for the reply sir !