BMW 801 question

[wiking85]

One of the biggest issues of German R&D during the war was the proliferation of projects being worked on; if the RLM got some sense and parred things down for BMW how much more quickly could the BMW 801 have developed. Let's assume that other than tweeking the BMW 132 and working on the BMW 003 BMW only is tasked with developing the 801 engine from 1938 onwards. That means no 802 or 803 work:
https://en.wikipedia.org/wiki/BMW_802
https://en.wikipedia.org/wiki/BMW_803
Both were historically cancelled in 1943 anyway.

Later developments of the 801 were quite high powered, but only appeared at the very end of the war or not at all. The 2000hp 801S showed up in Autumn 1944 and the 2400hp 801F was only just getting ready to be produced at war's end. Could either engine have been moved up appreciably has the 801 been the sole significant piston engine project from 1938 to the end of the war?

 

[tomo pauk]

The BMW have had the 801E developed and produced in 80 copies. In July and August of 1942, the engine passed several times the 100 hour test. Due to redesigned pistons, heads, oil system and compressor, the boost pressure for take off and emergency rating (Start Notleistung) was now 1.62 ata, vs. 1.42 ata for the fully rated 801D - meaning 2000 PS for take off and 1710 PS at 5650 m (power values probably without the power needed for the coling fan - meaning 70-50 PS less power for the prop at these ratings). However, doe to the need to introduce too many changes in production lines, the engine was abandoned, later some features (mostly the improved S/C) were used on the 801S of late 1944 (probably the 'power section' of the 801D, used for the 801S, proved as capable to withstand the stress).

So yes - the RLM/LW/BMW/Fw could have had the better 801 in service in, say, second half of 1943.

 

[wiking85]

The BMW have had the 801E developed and produced in 80 copies. In July and August of 1942, the engine passed several times the 100 hour test. Due to redesigned pistons, heads, oil system and compressor, the boost pressure for take off and emergency rating (Start Notleistung) was now 1.62 ata, vs. 1.42 ata for the fully rated 801D - meaning 2000 PS for take off and 1710 PS at 5650 m (power values probably without the power needed for the coling fan - meaning 70-50 PS less power for the prop at these ratings). However, doe to the need to introduce too many changes in production lines, the engine was abandoned, later some features (mostly the improved S/C) were used on the 801S of late 1944 (probably the 'power section' of the 801D, used for the 801S, proved as capable to withstand the stress).

So yes - the RLM/LW/BMW/Fw could have had the better 801 in service in, say, second half of 1943.

What was different between the S and E? If they were going to phase the S in anyway, why didn't they do it in 1942-43? Was it just that they couldn't afford the disruption that much?

 

[tomo pauk]

The 801E represented a major redesign vs. the 801D. Some details I've already listed here:

Due to redesigned pistons, heads, oil system and compressor, the boost pressure for take off and emergency rating (Start Notleistung) was now 1.62 ata, vs. 1.42 ata for the fully rated 801D

The compressor was equipped with rotating vanes (Vorzatslaufer). The S/C gear ratio was increased for the 1st S/C speed.

801S was based on 801D, with compressor and cylinder heads from the 801E, also with increased S/C gearing for the 1st speed.

If they were going to phase the S in anyway, why didn't they do it in 1942-43?

The 801S was not ready in 1943. There wasn't any 'contingency plan' (or plan B) that would put the 801S in production in case the 801E encounters problems of any sort.
On 2700 rpm and 1.42 ata, the rated height for the 801S should be at some 6500-7000m, instead of 5700 m for the 801D.

Was it just that they couldn't afford the disruption that much?

They probably could not - the production of the 801D in Berlin area (at Bramo's) really got in the stride in in early 1943, where the production of 100 engines per month was reached in mid 1943. The production at Argus is listed at 350 pcs in 1942, don't know why they didn't put more emphasis on this source - zero sum game?

 

[wiking85]

The 801E represented a major redesign vs. the 801D. Some details I've already listed here:

The compressor was equipped with rotating vanes (Vorzatslaufer). The S/C gear ratio was increased for the 1st S/C speed.

801S was based on 801D, with compressor and cylinder heads from the 801E, also with increased S/C gearing for the 1st speed.



The 801S was not ready in 1943. There wasn't any 'contingency plan' (or plan B) that would put the 801S in production in case the 801E encounters problems of any sort.
On 2700 rpm and 1.42 ata, the rated height for the 801S should be at some 6500-7000m, instead of 5700 m for the 801D.



They probably could not - the production of the 801D in Berlin area (at Bramo's) really got in the stride in in early 1943, where the production of 100 engines per month was reached in mid 1943. The production at Argus is listed at 350 pcs in 1942, don't know why they didn't put more emphasis on this source - zero sum game?

What took so long to make the D into the S?

 

[Shortround6]

It may depend on what is involved in the redesign of some of the parts. Maybe they could be made using much of the same tooling, maybe not?

Changing from an R-2800-B to a R-2880-C cylinder head meant changing from a casting to a forging and that forging was treated to 4 different drop forge operations using two different type drop forges. Then the fins were machined in using ganged slitting saws following patterns/cam profiles.

I don't know what BMW changed between the two heads. You can't make 1900hp Wright R-2600 heads on the sam emachinery as the 1700hp R-2600 heads and the Hercules went through around 5-7 different cylinder heads in it's history. Some could be made with existing foundry and machine tools, some could not.

 

[tomo pauk]

The 801E and S used cast cylinder heads.

What took so long to make the D into the S?

A million dollars question

 

[stona]

Slightly tangential, but it has always surprised me how immune to rationalisation the aircraft industry was compared to others. There was a rationalisation and concentration on production of only the most essential equipment in early 1944 that seems to have by-passed the aircraft industry. The plan was that, as examples, types of light infantry weapons would be reduced from 14 to 5, anti-tank weapons from 14 to 1, anti-aircraft guns from 10 to 2 and vehicle models from 55 to 14. To a large extent this was accomplished. Inessential and non-military manufacture was analysed to reduce unneeded production. For example, 117 firms still making carpets was reduced to 5, the 900 machine tool firms were reduced to 369. Overall 415,700 workers were freed up for military production as well as a huge area factory floor space in early 1944, yet the plethora of expensive and resource intensive projects in the aircraft sector continued, mostly with no useful results.

Cheers

Steve

 

[kool kitty89]

Slightly tangential, but it has always surprised me how immune to rationalisation the aircraft industry was compared to others. There was a rationalisation and concentration on production of only the most essential equipment in early 1944 that seems to have by-passed the aircraft industry. The plan was that, as examples, types of light infantry weapons would be reduced from 14 to 5, anti-tank weapons from 14 to 1, anti-aircraft guns from 10 to 2 and vehicle models from 55 to 14. To a large extent this was accomplished. Inessential and non-military manufacture was analysed to reduce unneeded production. For example, 117 firms still making carpets was reduced to 5, the 900 machine tool firms were reduced to 369. Overall 415,700 workers were freed up for military production as well as a huge area factory floor space in early 1944, yet the plethora of expensive and resource intensive projects in the aircraft sector continued, mostly with no useful results.

The British seemed to do a reasonable job with 'rationalizing' aircraft development, production, and aero engine development and production early war. In hindsight a bit too conservative in some areas and too liberal in others (or just odd or out of place -mismanaged)

Germany didn't seem to really achieve this with the initial early war (1939-40) freeze on military funding of advanced projects seen as irrelevant to the short war planned to thereafter skipping over some of the simpler/earlier advanced designs to focus on far more troublesome designs with loftier (often unrealistic) design goals ... or ever-shifting requirements.

Lack of focus on aggressive defensive weapons build-up when the war turned against them (like the British did during the BoB) was a major problem as was lack of support or proper planning for the motorized transportation infrastructure. (including lack of modern, efficient military transport aircraft -cancellation of the Fw 206 and shelving/delay of the Ju 252 left the obsolete Ju 52 as the LW's primary transport)

 

[BogdanRadulescu]

Hello.
Any one has drawings of the cylinders of the BMW 801 side and fron/rear? I've started to work on 3D software and it is my "dream" to make a 3D BMW 801 and print it

Thank you