109 prop pitch (rpm) and the supercharger

[ACE-OF-ACES]

Originally Posted by Crumpp

It is all about maintaining optimum pitch and rpm.

As you coarsen the pitch to reacquire the rpm, you will notice an increase in performance.

In the quoted cases, they are setting the engine to a limited over boost and coarsening the pitch to maintain rpm.

That is how it works.

Ok..

So on one had we have Crumpp telling us that is how it works, that the 109 pilots coarsen the pitch to maintain the RPM..

So we have an opinion of a modern day civilian trained pilot some 70 years after the fact as to how the 109 pilots did it..

But we also have the following..

Originally Posted by Ulrich Steinhilper

When we flew at that height, the engine only just gave enough pull and we constantly changed the propeller pitch and RPM to improve the performance. With a flat pitch we could increase the RPM of the engine and get more pressure from the super-charger. Then, by changing the pitch to a coarser setting, we could make up some speed.

Ok..

So we have Ulrich Steinhilper telling us that is how it works, that the 109 pilots constantly changed the propeller pitch and RPM to improve the performance..

So we have the opinion of an actual WWII military trained pilot as to how the 109 pilots did it..

Which is in conflict of how Crumpp said 109 pilots did it..

So at this point there is no need for any further discussion or debate..

Both sides have spoken!

A) Crumpp a modern civilian trained pilot
B) Steinhilper an actual WWII military trained pilot

Thus the only thing left to do is decide who do you want to belive

Crumpp or Steinhilper

For me the choice is simple

Steinhilper hands down!

[kohmelo]

Originally Posted by ACE-OF-ACES

A) Crumpp a modern civilian trained pilot

Scaries thing about this is he is says to maintain 2600RPM...

[ACE-OF-ACES]

Originally Posted by kohmelo

Scaries thing about this is he is says to maintain 2600RPM...

So

Is it safe to assume that I can put you down for a vote for Steinhilper over Crumpp?

Hmmm.. maybe I should start a poll on this?

[Crumpp]

Go ahead man....

It is par for the course in this community. Reality by vote....

[ACE-OF-ACES]

Originally Posted by Crumpp

Go ahead man....

It is par for the course in this community. Reality by vote....

Only because it is par for the course to take the word of an actual WWII military trained pilot who actually flew the plane over a civie trained pilot some 70 years after the fact.. Guess we are just silly like that!

[NZtyphoon]

Originally Posted by ACE-OF-ACES

Ok..

So on one had we have Crumpp telling us that is how it works, that the 109 pilots coarsen the pitch to maintain the RPM..

So we have an opinion of a modern day civilian trained pilot some 70 years after the fact as to how the 109 pilots did it..

But we also have the following..


Ok..

So we have Ulrich Steinhilper telling us that is how it works, that the 109 pilots constantly changed the propeller pitch and RPM to improve the performance..

So we have the opinion of an actual WWII military trained pilot as to how the 109 pilots did it..

Which is in conflict of how Crumpp said 109 pilots did it..

So at this point there is no need for any further discussion or debate..

Both sides have spoken!

A) Crumpp a modern civilian trained pilot
B) Steinhilper an actual WWII military trained pilot

Thus the only thing left to do is decide who do you want to belive

Crumpp or Steinhilper

Ummmm, this is so tough...lemme see. Umm a Luftwaffe pilot who flew the 109 in combat v Crumpp. Oh gosh I think it'll have to be the 109 pilot.

[IvanK]

Regarding this quote that has popped up in this thread:

"To increase the performance of the Me 109 an increase in the revs for a short time at heights over 5.5 km. will be in future be
permissible. For the DB 601 A engine the normal maximum revs are 2400.
Above full pressure height they may be for a short time be increased
from 2400 to 2600."

Here is the source document for this quote. It would appear to be a translation of a captured German document. It would also appear to be conditional on Auto Prop pitch installation. Sorry about the quality its as good as I can get. It does put into perspective the use of this increase in RPM and the issues associated with it.

[NZtyphoon]

Originally Posted by IvanK

Regarding this quote that has popped up in this thread:

"To increase the performance of the Me 109 an increase in the revs for a short time at heights over 5.5 km. will be in future be
permissible. For the DB 601 A engine the normal maximum revs are 2400.
Above full pressure height they may be for a short time be increased
from 2400 to 2600."

Here is the source document for this quote. It would appear to be a translation of a captured German document. It would also appear to be conditional on Auto Prop pitch installation. Sorry about the quality its as good as I can get. It does put into perspective the use of this increase in RPM and the issues associated with it.

Thanks for this Ivan. Presumably some pilots were exceeding the limits for too long or were doing so too often, thus stressing the engine: shades of Dowding's comments about over-use of +12 lbs boost.