Greg strikes again - Bf 109G-6 was so slow compared to P-51D

[tomo pauk]

Yep - meant MG 151

bulges for 15mm MG 131

Bill - there were no bulges for the MG 151 on the 109G

 

[Vincenzo]

deleted
tomo already did the point

 

[drgondog]

bulges for 15mm MG 131

Bill - there were no bulges for the MG 151 on the 109G

Typo for 15mm, meant MG 131 13mm and I believe the 'bulge' wa required due to the upgrade from MG 17s

 

[dedalos]

Typo for 15mm, meant MG 131 13mm and I believe the 'bulge' wa required due to the upgrade from MG 17s

The bulges for the heavy machine guns were not required, as it was proved in the later versions of the bf109. They were introduced in the bf109g6 as a fast way to put hmgs into production as soon and as easy as possible. Along with similar choices in other parts of the aircraft the end result was the Bf109G6 was an aerodynamic nightmare.

 

[Denniss]

They were required without considerable change of parts. The cleaner looking /AS and K had a changed engine cover as that had to be extended anyway due to larger supercharger requiring more space

 

[planespotting]

Against anything that was not Bf 109 of the era, and before Spitfire IX arrived, it was a ball of fire. Including the above 20000 ft altitude band. Expecting that enemy will fight at one's favorable altitude band is a surefire way to loose.

I'd always understood that the FW.190 wasn't that great higher up, and that the new "universal" wing on the Spitfire had a negative impact on some aspects of performance, but maybe that's just a story we tell ourselves in the UK...

 

[PAT303]

The FW190 was king around 20,000ft which is why the Spit MkIX with Merlin 66 was born,

 

[Thumpalumpacus]

The FW190 was king around 20,000ft which is why the Spit MkIX with Merlin 66 was born,

... and when the bombers are at ~26,000ft and the P-47s a bit higher ...

 

[tomo pauk]

I'd always understood that the FW.190 wasn't that great higher up, and that the new "universal" wing on the Spitfire had a negative impact on some aspects of performance, but maybe that's just a story we tell ourselves in the UK...

Qualifiers needed for Fw 190 (not) being great higher up should include the answers to the questions 'against whom?' and 'when?'

 

[planespotting]

Qualifiers needed for Fw 190 (not) being great higher up should include the answers to the questions 'against whom?' and 'when?'

I meant it as a general comparison with both the intended opposition and the alternative, i.e. Spitfire and Bf 109, and by extension other good single-engined fighters in the same game, such as the Mustang, Jug, and Yak (though maybe less so the Tiffy/Tempest and the La-5, which were more optimised for low-down)...

My (amateurish) understanding is that the Focke Wulf's advantages were its high speed at very low alittudes around 5000ft, and its superb roll-rate, hence modifying the Spitfire with a shortened, square-ended wing in response - the RAF found that the reduced wing loading did allow the Spitfire to keep pace with the FW 190 low down, but the roll-rate, while much improved, wasn't really enough, and it lost something of its overall performance in the turn and climb, so while a square-ended Spit could still out-turn a Focke Wulf, this was only becuase this was something which the Focke Wulf was never particularly good at, and I'm not sure how much of an edge it retained against a Bf 109...

A quick google brings up FW 190 speed charts which show that it's blisteringly fast at low level to roughly 5000ft, then falls off sharply to around 10,000ft, then starts to speed up again until it passes the Spitfire in a narrow window around 20,000ft, where it falls off again; those who know more than me can probably explain the reason for the zig-zag curve, but I would hazard that what's shaping my perception are RAF-derived narratives more concerned with its roll-rate and consistently better performance down low rather than the "headline" speed advantage in the narrow altitude-band at 20,000ft...

I once came across some squadron-level sources from Normandy (summarised in an Osprey volume, I think) which suggested that the Fw 190s in Normandy were performing low-level tip-and-run largely undisturbed by the Allies, which made me wonder if the Anglo-American perception of air superiority was simply because they weren't encountering the opposition at higher altitudes...

And at this point, when I started to look for climb figures, I realised that I only think of the Fw 190 as being relevant until mid-1944, when it was forced to abandon its traditional activities over southern England, the Channel and northern France, for reasons that had nothing to do with its performance. Dora is, as you say, a different thing in a different game...

I'm not at all sure how well the Fw 190A climbed, either; the Fw 190D gave results in the range of a high-end Spitfire V, but... well, I have no idea why they were trying to reinvent a low-level fighter as an interceptor in the first place...

 

[Deleted member 68059]

A quick google brings up FW 190 speed charts which show that it's blisteringly fast at low level to roughly 5000ft, then falls off sharply to around 10,000ft, then starts to speed up again until it passes the Spitfire in a narrow window around 20,000ft, where it falls off again; those who know more than me can probably explain the reason for the zig-zag curve,

It was very fast at low level as it has a huge engine with loads of power, but sadly a very under-developed supercharger with a sole redeeming factor of a 2-speed gear drive.

 

[planespotting]

It was very fast at low level as it has a huge engine with loads of power, but sadly a very under-developed supercharger with a sole redeeming factor of a 2-speed gear drive.

You're much more likely to know the answer than me, so I'm curious - was the combination of low-level performance and impressive-looking headline speed at higher altitude something the designers could deliberately tune the design for, or did the limits of technology dictate the gap bewteen the heights?

I'm suddenly hit by the thought that people designing a radial with strong take-off power and high-performance level flight at a specific altitude in 1930s Germany were probably thinking less of fighters than they were of the big round firewalls on the Ju 88...

 

[Deleted member 68059]

You're much more likely to know the answer than me, so I'm curious - was the combination of low-level performance and impressive-looking headline speed at higher altitude something the designers could deliberately tune the design for, or did the limits of technology dictate the gap bewteen the heights?

I'm suddenly hit by the thought that people designing a radial with strong take-off power and high-performance level flight at a specific altitude in 1930s Germany were probably thinking less of fighters than they were of the big round firewalls on the Ju 88...

I dont have a BMW document saying "lets not do a good supercharger because of ...XYZ".

Certainly they knew that very good high altitude performance was going to be necessary very early, Daimler-Benz were doing 2-stage superchargers in 1936.

I suspect the main reason the 801 was behind in the supercharger was that BMW had needed to switch from water to air cooled engines by the German Air Ministry,
having already put a lot of effort into their own water cooled V12s (BMW 115, 116, 117). So they bought a licence from P&W to license build American radials
for a bit to kick start their own progress. I dont think they had time to develop all that into their own radial AND totally change the supercharging system concept.

 

[tomo pauk]

I suspect the main reason the 801 was behind in the supercharger was that BMW had needed to switch from water to air cooled engines by the German Air Ministry, having already put a lot of effort into their own water cooled V12s (BMW 115, 116, 117). So they bought a licence from P&W to license build American radials for a bit to kick start their own progress.

Did the BMW 115, 116 and 117 happened earlier than the license deal with P&W?

 

[Deleted member 68059]

Did the BMW 115, 116 and 117 happened earlier than the license deal with P&W?

I don't think so no, but the order to concentrate only on air cooled was.

 

[Shortround6]

BMW taking up the P & W engine seems hard to pin down. P & W shipped an engine to BMW in May 1933 but that certainly doesn't prove a license agreement. It appears that the Ju 52 used a succession of BMW engines that started as licensed copies. Aside from the JU-52s the BMW 132 doesn't seem to have gone into much until 1936-37.

 

[Deleted member 68059]

BMW taking up the P & W engine seems hard to pin down. P & W shipped an engine to BMW in May 1933 but that certainly doesn't prove a license agreement. It appears that the Ju 52 used a succession of BMW engines that started as licensed copies. Aside from the JU-52s the BMW 132 doesn't seem to have gone into much until 1936-37.

(My booky-wook pg 105)

SOURCE:

 

[z42]

I suspect the main reason the 801 was behind in the supercharger was that BMW had needed to switch from water to air cooled engines by the German Air Ministry,
having already put a lot of effort into their own water cooled V12s (BMW 115, 116, 117). So they bought a licence from P&W to license build American radials
for a bit to kick start their own progress. I dont think they had time to develop all that into their own radial AND totally change the supercharging system concept.

I started a thread arguing something along this line a few days ago at In retrospect, were the BMW radial engine developments a mistake?