Fw 190A

[Zoom]

Most of what I have read has said that the A-3 thru A-8 models all used the BMW-801D-2 engine. If this is the case then what accounts for the performance differences of the different models, especially the jump in top speed from ~390 to 400+ mph from A-3 to A-4? Were different boost levels/systems or superchargers used? I don't think MW-50 was employed until the A-8 model so something else must account for the differences in top speed. I know that after the A-4 the top speed stayed the same or decreased due to weight increases, but the A-3 and A-4 were basically the same plane so shouldn't they have similar top speeds?

[Panzzer]

A-4 already had the MW 50.

[Bruno]

No A series 190 was serialized with MW-50.

The A-4 was fitted at the factory with the 'plumbing' for MW-50 but only a handful of Jabo aircraft were actually fitted.

Some early batches of A-3s were still fitted with BMW 801C-2. The A-3 fitted with the BMW 801D-2 was cleared for 1.42 ata @ 1 min. The British test of the Farber A-3 lists max ata at 1.35. I don't know why. Could be the allied fuel but I don't I know.

The A-4 was was cleared 1.42 ata @ 1 minute as well. With the A-5 boost was cleared for 1.42 ata @ 3 min.

In '43 the A-5 was tested with C3-Einsptritzung. It was eventually cleared (don't know the exact time frame) for Schlachtflugzeugen and could only be used below 1k. C3 fuel was injected into the eye of the supercharger cooling the charge allowing for higher boosts, 1.58 ata, by reducing the risk of detonation. This was limited to 'as long as the emergency lasted'.

In July '44 'C-3 emergency power' was cleared for all 190As for both blower stages. The A-8 for example was cleared for 1.58 ata in low blower, and 1.65 in high. The limit was set to 10 min in both stages. 'C-3 emergency power' worked the same way as C3-Einsptritzung in that C-3 fuel was injected into the eye of the sc cooling the charge allowing for higher boost. Fuel consumption was high 840l per minute. There were differences between 'C3-Einsptritzung' and 'C-3 emergency power' but I will let those with a higher level of knowledge answer.

As for the speed variances between the A-3, A-4 and A-5 they do seem that great when all 3 run 1.42 ata. The charts I have seen show 410mph for the A-3, 414 mph for the A-4 and 415 mph for the A-5. I don't collect charts though and only have a passing interest in the 190A series. Maybe some one else could better expand on my answers.

[Panzzer]

Oh, okay. I'm sorry, I thought the A-4's had the MW-50 already. Thanks for the correction, Wotan.

Any sources? (Also known as book recommendations?)

[gripen]

I found this from NASM microfilms. Apparently there was some limitations in the beginning of the service.

gripen

[storch]

look up crumpp's well document threads on this topic

[Charge]

And look out for trolls gathering...

-C+

[gripen]

Hm... I don't recall anyone posting such evidence as above on early ratings of the BMW 801D.

gripen

[joeblogs]

Set aside the MW50, I have found suprisingly little variation in the data reported on the output of that BMW engine over the years of the war.

I don't know if this is simply an issue of translations I can find, or simply that I am looking in the wrong place.

-Blogs

Originally posted by Zoom
Most of what I have read has said that the A-3 thru A-8 models all used the BMW-801D-2 engine. If this is the case then what accounts for the performance differences of the different models, especially the jump in top speed from ~390 to 400+ mph from A-3 to A-4? Were different boost levels/systems or superchargers used? I don't think MW-50 was employed until the A-8 model so something else must account for the differences in top speed. I know that after the A-4 the top speed stayed the same or decreased due to weight increases, but the A-3 and A-4 were basically the same plane so shouldn't they have similar top speeds?

[Charge]

I think it has been discussed many times before, if I were you I'd search threads which Crumpp has participated and be prepared to comb through all the BS between Crumpp and Gripen&Co.

-C+

[gripen]

Hm... The answer to the Zoom's question might be that according to documentation, in the beginning of the service the BMW 801D seem to have been limited to 1,35ata 2450rpm and lower speed values of the A-3 are for this setting.

And yes, it has been discused here many times but no one has come up with documentation on the limit.

gripen

[Bruno]

Hm... The answer to the Zoom's question might be that according to documentation, in the beginning of the service the BMW 801D seem to have been limited to 1,35ata 2450rpm and lower speed values of the A-3 are for this setting.

And yes, it has been discused here many times but no one has come up with documentation on the limit.

I think you are right. If 1,35 ata @ 2450 rpm were max then that would answer Zoom's question. I knew that the Farber's A-3 was tested at 1,35 ata but didn't know why. I have only heard explanations that speculated everything from different fuel to the Brits mis-calculation / reading the boost gage.

Any idea as to when 1,42 ata was cleared?

[Debonair]

the RAF tested their captured A-3 at 1.42.  
390mph @ 18,000'/full throttle height.

[joeblogs]

Most of those discussions were about a limit on the DB601, not BMW801.

I've not even seen much in the way of documenting changes in max RPM for the BMW.

BTW even the early models of this engine were rated at 2,700 RPM. There are ratings for 87 and 92 octane but they don't seem to matter much, at least at sea level.

-Blogs

Originally posted by Charge
I think it has been discussed many times before, if I were you I'd search threads which Crumpp has participated and be prepared to comb through all the BS between Crumpp and Gripen&Co.

-C+

[Bruno]

the RAF tested their captured A-3 at 1.42.
390mph @ 18,000'/full throttle height.

Kutscha (MiloMorai) posted this scan on another forum. It's consistent with what I have read in that the British tested Faber's A-3 at 1.35 ata max.

British test of Faber's A-3: