109 prop pitch (rpm) and the supercharger

[Crumpp]

All they did was manipulating the pitch to let rpm increase, and then - by when the rpm has increased - manipulating pitch to compensate for increase airspeed AND maintain increased rpm.

Exactly.

I have been saying this for how many pages now??



This community is toxic.

[Robo.]

Originally Posted by Crumpp

(All they did was manipulating the pitch to let rpm increase, and then - by when the rpm has increased - manipulating pitch to compensate for increase airspeed AND maintain increased rpm.)

Exactly.

I have been saying this for how many pages now??



This community is toxic.

No. You were saying that they were changing the pitch to keep it constant. That is something completely different.

The rpm won't stay up when you coarsen up, it will drop when you touch the rpm lever again. That's all I am saying.

[Crumpp]

You were saying that they were changing the pitch to keep it constant.

Go back and read what I wrote. You did not understand it and keep misinterpreting something.


Second thought, don't...

Just keep believing you have the concept and are correct. Welcome to the ignore list.

[Robo.]

Originally Posted by Crumpp

Go back and read what I wrote. You did not understand it and keep misinterpreting something.

So how exactly do you change the rpm to keep it constant again?

[kohmelo]

About the supercharger...

At "normal flying alttitude" I really don't believe that pulsing engine rpm to add small boost to supercharger rpm would be efficient. As it takes its RPM directly from engine RPM there would be no (turbo)lag and it would not transfer the "kick" when coarsening the pitch.
Centrifugal Supercharger (as in DB601) gives more boost the higher the rpm is and because the rpm relevant of the Engine RPM, the extra boost is lost when engine RPM is dropped.

Still if there is some changes on superchargers own pitch on level flight this is incorrect but I would believe that Chargers pitch changes only by alltidute Untill it hits its top performance pitch. --> After this point the extra oxygen was given by water-Methanol injection? because german belived that extra stage or added turpo would be heavier for added high alt performance than MV-50

[Crumpp]

Cruising at Dauerleistungen 1.15ata @ 2200U/min our pilot wants to increase speed.

So he puts the propeller to fine pitch until the rpm gauge reads 2400/U min and then increases manifold pressure until the manifold pressure gauge reads 1.3ata.

The airplane acelerates and he coarsens the pitch to maintain 2400/U min.

Pretty simple stuff.....

[bongodriver]

So we have gone from Steinhilper talking about maintaining max climb rate by adjusting prop RPM (which makes a pulsating resonance indicating frequent changes of RPM) to 'cruising' at 2200 RPM and simply changing to 2400 RPM to maintain and Crumpp hasn't changed the story how?

[Robo.]

Originally Posted by Crumpp

Cruising at Dauerleistungen 1.15ata @ 2200U/min our pilot wants to increase speed.

So he puts the propeller to fine pitch until the rpm gauge reads 2400/U min and then increases manifold pressure until the manifold pressure gauge reads 1.3ata.

The airplane acelerates and he coarsens the pitch to maintain 2400/U min.

Pretty simple stuff.....

Our pilot flies at 7km, he's struggling with performance up there, way above the FTH, his manifold pressure will not read 1.3 ata in the first place.

We're not talking about Dauerleisting below FTH. Down there the fiddling with rpm doesn't help much. You don't want to keep the engine at 2400/U, you want to coarsen down afterwards (your rpm drops down again), keep that speed and repeat that whole process again. That is the difference between 'change' and 'maintain'. Sorry I can't explain that any better or simpler. Just read what Steinhilper is saying and doing.

[ACE-OF-ACES]

Originally Posted by Robo.

So how exactly do you change the rpm to keep it constant again?

Only one way..

He has to redefine the meaning of 'maintain'

http://www.youtube.com/watch?v=j4XT-l-_3y0

Clinton would be proud!

[pstyle]

My understanding from the text is that rpm would oscillate with this technique.

Also that there would be a corresponding oscillation in engine sound. Steinhilper footnotes this.