Author Topic: German Language article on BMW801D boost systems (Read 2656 times)

Wotan · « **on:** December 14, 2004, 07:50:37 AM »

Gillle posted this on LEMB

In this thread:
Very interesting German article on BMW801D boost systems

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Here are scans of a recent article in a German aviation magazine describing the testing and installation of MW-50 and C3 injection boost systems in the FW190A, all very kindly supplied to me by Wastel:

http://img11.exs.cx/img11/7306/klassikerdieleistungssteigerun.jpg

http://img11.exs.cx/img11/7471/klassikerdieleistungssteigerun1.jpg

http://img11.exs.cx/img11/4048/klassikerdieleistungssteigerun2.jpg

http://img11.exs.cx/img11/3692/klassikerdieleistungssteigerun3.jpg

http://img11.exs.cx/img11/8185/klassikerdieleistungssteigerun4.jpg

http://img11.exs.cx/img11/365/klassikerdieleistungssteigerun5.jpg

MANDO · « **Reply #1 on:** December 14, 2004, 06:42:47 PM »

It needs some translation

Fw190 2700 rpm / 1.42 ata BMW801D2 without C3 injection
1800 PS sea level
1490 PS 19028 feet
341 mph sea level
400 mph 20770 feet

Fw190 2700 rpm / 1.58/1.65 ata BMW801D2 with C3 injection (10-15 minutes)

2050 PS sea level
1695 PS 19028 feet
359 mph sea level
405 mph 18044 feet

Crumpp · « **Reply #2 on:** December 14, 2004, 07:47:22 PM »

Good article. He has a short list of references.

Crumpp

gripen · « **Reply #3 on:** December 15, 2004, 04:20:31 AM »

The most interesting part is this:

The speeds reached at Rechlin were some 30-40 km/h lower than claimed by Fw. If compared to RAE and US Navy data , the Rechlin measurements are in the same ballpark.

gripen

Charge · « **Reply #4 on:** December 15, 2004, 04:28:38 AM »

Höhe?

-C+

Crumpp · « **Reply #5 on:** December 15, 2004, 05:11:32 AM »

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The speeds reached at Rechlin were some 30-40 km/h lower than claimed by Fw. If compared to RAE and US Navy data , the Rechlin measurements are in the same ballpark.

You need to check again, Gripen.

These are spot on with FW.

http://www.terra.es/personal2/matias.s/190-2-1024.jpg

565kph....... 1.62ata

You also need to notice on the chart the different pressures they experimented with....

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Höhe?

Altitude. 100 meters.

Crump

gripen · « **Reply #6 on:** December 15, 2004, 05:33:25 AM »

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Originally posted by Crumpp
You need to check again, Gripen.

These are spot on with FW.

http://www.terra.es/personal2/matias.s/190-2-1024.jpg

565kph....... 1.62ata

Hm... there was no A-8 in the test. Fw 190A-5 SS+GL was a fastest of the tested planes and it did 575 km/h at 100m with 1,63 ata 2700 rpm at test conditions. The speed increase over 1,42 ata 2700 rpm was 40 km/h ie SS+GL did about 535 km/h with 1,42 ata, about same as US Navy Fw 190. Other tested planes were slower; 520-530 km/h ie about as fast as MP499 at RAE.

Basicly the FW data on A-5 is not realistic and even the Fw data on A-8 seem to be quite bit on optimistic side. Very typical for manufacturers claims.

gripen

Crumpp · « **Reply #7 on:** December 15, 2004, 05:51:14 AM »

It is the Lufterrad. Again these aircraft where flown by Focke-Wulf as part of the FW-190A upgrades in the program.

So.

Yes it is an FW-190A5 but it is the "prototype" FW-190A8.

Got the report and the original graphs. Already gave it to Pyro.

There is good agreement between the Rechlin and Focke Wulf data.

What you want to compare is the worst in variation with the best in variation. Different flight test's on different days will have variations even on the same plane. The engine settings are different on each of these flights so you can expect some variation especially since they are searching for the correct engine set up for maximum performance.

There is not good agreement between the US Navy test and the Rechlin data. The US Navy test is way off.

Some of the data in the US Navy report does agree but not the level speed measurements. All the data that does agree only matches German numbers because the US Navy copied it out of the Flugzueg-Handbuch.

Crumpp

gripen · « **Reply #8 on:** December 15, 2004, 06:46:32 AM »

Hm... the data is clear, the tested planes reached around 520-535 km/h near sea level with 1,42 ata 2700rpm, about 10-25 km/h less than Fw claim for A-8 and 30-45 km/h less than Fw claim for A-5. We don't know if these planes were fitted with different cooling fans (probably not because the tests were done in spring and summer 1943) but that can't explain the difference if compared to the FW data on A-5 and A-8.

gripen

Crumpp · « **Reply #9 on:** December 15, 2004, 06:59:57 AM »

I do know the set up. And yes the Lufterrad dropped the performance 15 km ON AVERAGE.

Crumpp

GScholz · « **Reply #10 on:** December 15, 2004, 07:46:44 AM »

Why would they test it without the cooling fan?

Crumpp · « **Reply #11 on:** December 15, 2004, 07:55:39 AM »

They have the 14 bladed Lufterrads. I have the report and Pyro has the performance graphs from it. The Lufterrads varied performance on AVERAGE of 15kph reduction in top speed.

These FW-190A5's are the prototype FW-190A8's. They FW-190A5 was never cleared for 1.58/1.65 as it was not in service when the boost pressure was raised in Jul '44.

Are we going to go through another "Filled and Polished" episode?

Crumpp

GScholz · « **Reply #12 on:** December 15, 2004, 08:01:44 AM »

I wasn't aware we have had one earlier. I just don't get why the fan was not used for the tests when it is an essential part of the engine? You are saying that the fans were not used for the tests and that they deteriorated performance on operational aircraft?

gripen · « **Reply #13 on:** December 15, 2004, 08:06:05 AM »

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Originally posted by Crumpp

Are we going to go through another "Filled and Polished" episode?

Well, the Fw data for A-5 is claimed to be be "Gespachtelt u.Poliert" and we don't even know if it's tested data or just manufacturers claims to sell planes for RLM. And for one reason or another you are using that data for comparisons. Above data shows clearly that an average Fw 190 did about same as US Navy tested and RAE tested Fw190s, it also shows that manufacturers claims are far in optimistic side regardless "Lufterrad" type.

gripen

Crumpp · « **Reply #14 on:** December 15, 2004, 11:20:06 AM »

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Well, the Fw data for A-5 is claimed to be be "Gespachtelt u.Poliert" and we don't even know if it's tested data or just manufacturers claims to sell planes for RLM.

1. I don't think that by the FW-190A5 Focke-Wulf had to worry about selling planes to the RLM.

2. The FW-190A5 graph is not the one in question and I don't believe will be the data Pyro will use anyway.

3. The "Filled and Polished" fiasco was with your insistance that this graph:

http://www.terra.es/personal2/matias.s/190-2-1024.jpg

Was not a mistranslation of the aircraft finish.

So let's not switch documents around just so you can convince yourself you were not in error. You were wrong just as you are about the FW-190A5's speed now.

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I wasn't aware we have had one earlier. I just don't get why the fan was not used for the tests when it is an essential part of the engine? You are saying that the fans were not used for the tests and that they deteriorated performance on operational aircraft?

There is a 12 bladed Lufterrad and a 14 bladed Lufterrad. The 14 bladed fan is found on FW-190A8's that used BMW801T series motors and any BMW801D2's equipped with "Special Emergency Power for fighters". The 14 bladed Lufterrad increases cooling of the engine at higher boost pressures but lowers the overall top speed at lower boost pressures (1.42ata) by an average of 15kph. This is the main reason the FW-190A8 goes so much slower at 1.42ata than previous FW-190A's.

What this article does say is that MW-50 use was much more common in FW-190A's than we think. This is backed up by the documentation I have and pilots anecdotes.

Crumpp