BF-109F-4 - The use of 1.42 ata

[Laurelix]

So I know this ata was banned from use most of the time and only rarely permitted.

Was this due to severe engine over heating?
If so how long was the use of 1.42 ata permitted? 1 minute power? 5 minute power?

 

[Deleted member 68059]

So I know this ata was banned from use most of the time and only rarely permitted.

Was this due to severe engine over heating?
If so how long was the use of 1.42 ata permitted? 1 minute power? 5 minute power?

For details on the nitty-gritty of the engine problems you`ll be best watching this:



With regards to the actual data on permitted times of use see below, although I suspect
that these times were varied depending on the state of the engines at the time. You`ll
find various things written which conflict, hence probably the confusion resulting in your
original question.

These reports below were by the British, but the data is just translations of whatever the
engine data card found in the aircraft said. So should be regarded as accurate.

For earlier E-7 versions with 601N (Royal Aircraft Establishment - 9th July 1941 date of crash and,
as you can see has been de-rated, with 1.42 ata. not permitted).

For earlier F versions with 601N (Royal Aircraft Establishment - Oct 1941 trials)

This appears to have changed slightly with the 601E of F-4 (Royal Aircraft Establishment - Nov 1943 trials)

 

[Laurelix]

For details on the nitty-gritty of the engine problems you`ll be best watching this:



With regards to the actual data on permitted times of use see below, although I suspect
that these times were varied depending on the state of the engines at the time. You`ll
find various things written which conflict, hence probably the confusion resulting in your
original question.

These reports below were by the British, but the data is just translations of whatever the
engine data card found in the aircraft said. So should be regarded as accurate.

For earlier E-7 versions with 601N (Royal Aircraft Establishment - 9th July 1941 date of crash)

View attachment 593221

For earlier F versions with 601N (Royal Aircraft Establishment - Oct 1941 trials)

View attachment 593219

This appears to have changed slightly with the 601E of F-4 (Royal Aircraft Establishment - Nov 1943 trials)

View attachment 593220

Thanks that's perfect

 

[Laurelix]

What if after 3 minutes of WEP, the pilot cools the engine down by going to cruise power and then goes for another 3 minutes of WEP?

 

[Deleted member 68059]

Early versions had a clockwork mechanism which was triggered by pushing the throttle through the gate.

However, I would not get too caught up in details like this as many aircraft were found to have had this mechanism removed. Hence I dont
think it is particuarly relevant for what real operational conditions were like, in other words experienced pilots probably preferred to
"manage" these things themselves.

 

[tomo pauk]

The manual for the DB 601E-G engines, dated February 1942, lists the 2700 rpm and max boost of 1942, with remark that such engine rating (Start & Notleistung) can be used only if the RPM limiter (that can't be deactivated by pilot) is installed. Unfortunately, I was not able to find the time limit for the Start & Notleistung.
Manual was available on the cockpitinstrumente site.

The 1st date, that I'm aware, where the Notleistung is listed for the 109F-4 is the 10th December 1941, on the test report - comparison between 109F-4 and Fw 190A-2 ("Bei Notleistung ergibt sich dasselbe Bild. " - roughly: "When Notleistung is used, the situation is the same." )

 

[taly01]

Thanks for the video I must get your book "THE SECRET HORSEPOWER RACE - WESTERN FRONT FIGHTER ENGINE DEVELOPMENT" when it comes out on September 21, 2020.

Its enlightening that something as "boring" as nickel for exhaust valves was so crucial to Fw190 and Me109F/G engine problems (also for Me262 turbine blades I remember). I enjoyed reading Milch's quotes as he is someone I have been trying to understand, but it seems I have maligned him for not allowing more advanced development projects, when the LW struggled with basic problems!

The difference in performance between test program high quality engines and fuel vs production and field service engines and fuel is also something that plagued the Japanese Homare engine.

I find it amusing when British people always blame Hitler and the Nazi party for all Germany's mistakes...LOL It seems alot of blame lies with the engineers who were more excited to work on "interesting" new super engine projects rather than tedious fault rectification programs for current engines.

 

[Deleted member 68059]

I find it amusing when British people always blame Hitler and the Nazi party for all Germany's mistakes...LOL It seems alot of blame lies with the engineers who were more excited to work on "interesting" new super engine projects rather than tedious fault rectification programs for current engines.

I would place the blame at mid and senior management level. Not the designers & test engineers. If one takes that through to its conclusion you do need to blame the Nazi party as they influenced who the top management were. Depends a bit how many onion-layers you want to peel back when you look at it...