Hey Crumpp...

[Grits]

Were the power outputs for the 801D the same for the A-5 and A-8? I vaguely recall you sayin that the A-8 got a power increase, but all the info I can find on the net (the same ones that list the 10,800lbs weight number) dont list any differences in power after the A-4 added MW50 boost.

[Crumpp]

Were the power outputs for the 801D the same for the A-5 and A-8?

No they were not the same.  The BMW 801D2 was constantly improved.  At the same power settings the BMW 801D2 in the FW-190A8 gains around 200hp over the FW-190A5's BMW 801D2.  Adding in the additional boost raises this 200hp.  Max output a FTH was 2050hp.

The FW-190A8 was also fitted with different engines beginning in May 44.  These engines raised the power output to 2200 (+) hp depending on the model.

The FW-190A5 gained no power over the FW-190A3 but did gain a substantial chunk of weight.

The FW-190A8 gained some weight but added in a large chunk of additional power.

but all the info I can find on the net (the same ones that list the 10,800lbs weight number) don't list any differences in power after the A-4 added MW50 boost.

Not surprising.  To most people a BMW-801 is a BMW-801 and an FW-190A is an FW-190A.  They look the same and have the same name so therefore they are the same.

All the best,

Crumpp

[Wotan]

The FW-190A5 gained no power over the FW-190A3 but did gain a substantial chunk of weight.

Yes it did. the A-3 was de-rated to 1.32 max permissible boost.

The A-3 and A-5  engine was not really the same even though the D2 designation.

There were changes to the F66 (801F66) like the exhaust plating. It wasn't until the A-5 that the 801F66 was considered reliable and run at full designed boost.

In fact it could be run even higher then 1.42 ata. When they were testing C3 injection on the A-5 then ran it at 1.65 ata and it wasn't until the landed that they realized that C3 wasn't injected.

The A-3 for example had issues and was typically  limited to a lower boost setting (1.32 ata) because of overheating issues and exhausts burn through.

Even the A-4 never lived up design performance. The Rechlin tests of the A-4 were well below the  manufacturers data.

The BMW 801D2  was under constant development as Crumpp said but the A-5 was improved upon and did produce higher power over production A-3s.

[Crumpp]

In fact it could be run even higher then 1.42 ata. When they were testing C3 injection on the A-5 then ran it at 1.65 ata and it wasn't until the landed that they realized that C3 wasn't injected.

Correct but 1.58ata/1.65ata was not an official rating in the FW-190A5.  Until May 44 only FW-190A's beginning with the FW-190A5 jabo-einsatz's, using C3 boost could operate at increased pressure and were restricted to using it below 1 km in altitude.

The only FW-190A5 to use 1.59ata/1.65ata above 1 km officially was the FW-190A8 prototypes tested in Sept. 1943.

The FW-190A3 ran at 1.42ata. This is confirmed from multiple sources including the Flugzeug-Handbuch.





According to the Focke Wulf Factory engineering meeting minutes I have minutes of in June 1942, JG 26 was operating NO de-rated FW-190's.  JG 26 was getting 66 hours of engine life on average out its BMW801D2's at this time.  JG 2 was operating 6 de-rated motors that had operated 22 hours without incidence at the time of the meeting.  No reason is given for the de-rating.  Considering the R-2800 only averaged 50 hours of life during it's wartime service, the fact the Germans got 120 hours on average out of later 801's is pretty remarkable.

Lining the exhaust helped with cooling but added at the most a 5-7 percent horsepower increase if any.  Checking the power curves from an early BMW-801D2, mid war BMW-801D2, and late war BMW-801D2 confirms the power gains.  The FW-190A5 gained no power that I can see from the engine power measurements.

The BMW-801C's 3 minute rating was 1.32ata.



All the best,

Crumpp

[Wotan]

Julius Meimberg states in his memoirs that the A-3s they flew had a 'power limiter' that was installed at the factory.

He states the A-3 was limited to 1.32 ata until June '42 by order of RLM.

Sometime before June he asked to 'remove' the limit from the A-3s of 3./JG 2 but his request was denied by Erich Leie (Stab./JG 2). Leie already had the limit removed from his personal A-3.

Farber's (JG2 again) captured A-3 had the de-rated engine that was limited to 1.32 ata max permissible boost as well. In fact the Brits dogged this A-3 running above 1.32 ata for extended periods for the Vb and IX comparison trials.

JG2 had more then just 6 de-rated A-3s. They may have had 6 in June but at that point the limit was lifted but only after some of these issues were addressed. The A-3 entered service with JG26 in March. It was 3 to 4 months before the 1.42 ata restriction was lifted.

However, even then the A-3 never lived up to expected performance, neither did the A-4 (see the RLM tests at Rechlin).

It wasn't until the A-5 that production aircraft were able to deliver design performance. The A-5 being heavier but generally faster at the same boost.

[Crumpp]

Julius Meimberg states in his memoirs that the A-3s they flew had a 'power limiter' that was installed at the factory.

AFAIK looking at the stacks of Focke Wulf factory documents available to the foundation, there was no "factory" limitation.

The "de-rating" was most likely a Luftwaffe/Geschwader internal measure and by June 42 was no longer imposed except on a very few aircraft.  The "mechanism" was simply a screw that could be placed in the throttle to limit it's movement.  The threads for that screws emplacement is found on all FW-190's.  In fact most military aircraft have a similar system because de-rated motors are a common occurance in all military Air Forces.  It is simply and engine management tool.  The most common reason for de-rating aircraft is to use stocks of inferior grade aviation fuel.  This allows the service to conserve it's superior quality fuel for it's most urgent needs.  

The documentation from the factory says in June, the Luftwaffe was getting a substantial amount of time out of the BMW 801 series.  More than enough to consider it a reliable powerplant.  The BMW801D2 was never a problematic engine.  The BMW 801C went through a rocky teething period.  The BMW 801C1 and C2 benefited from the exhaust reroute and reliability increased tenfold.  The 801C series was only able to achieve 1.32ata tops.  The BMW 801D2 ran at 1.42ata.

All the best,

Crumpp

[Crumpp]

However, even then the A-3 never lived up to expected performance, neither did the A-4 (see the RLM tests at Rechlin).

Not a whole lot of performance difference between an FW-190A5 and the FW-190A3.

FW-190A3:



FW-190A5:




In fact it lost in the climb.  Which is exactly in keeping with what the FW-190A5 pilot's say about the A5, it was the worst performing varient.

All the best,

Crumpp

[MANDO]

While both climb charts (A3 and A5) are for 1.32 ata, the advantage of A3 is quite clear: 10 mps for A5 and 12 mps for A3 at 18k.