Is Spitfire really the BEST British fighter???

[DerAdlerIstGelandet]

Depends on the Aircraft. The Spitfire and the Bf-109 and Fw-190A stayed pretty close to each other on performance, the Fw-190D and Ta-152 overtook the Spitfire pretty much on performance. There were actually a lot of aircraft that would outperform a Spitfire but they were not built in large numbers to make any difference.

[alejandro_]

Yes, I have been involved in many discussions regarding the Bf-109G-10/K-4 vs Spitfires Mk XIV/21. I was surprised to read some facts I didn't know, for example the MW-50 limitations and cooling systems of P-51, Bf-109 and Spitfire. However, when I came accross the Bf-109 dara things didn't make that much sense. If the spitfire cooling is better, how comes it has a lower maximum cruising speed?

On the other hand I think that data should be taken with caution. The cruise velocities for a G-2 were much lower (I checked on the manual).

[DerAdlerIstGelandet]

Hmmm I am sure that there is a lot of info on performance out there that is incorrect.

[Lunatic]

Originally Posted by alejandro_

Yes, I have been involved in many discussions regarding the Bf-109G-10/K-4 vs Spitfires Mk XIV/21. I was surprised to read some facts I didn't know, for example the MW-50 limitations and cooling systems of P-51, Bf-109 and Spitfire. However, when I came accross the Bf-109 dara things didn't make that much sense. If the spitfire cooling is better, how comes it has a lower maximum cruising speed?

On the other hand I think that data should be taken with caution. The cruise velocities for a G-2 were much lower (I checked on the manual).

Maximum cruising speed for the Spitfire and the Bf109's (late G models and K) were about 375 mph at high altitude, which is about the same. In both cases, the maximum time such a cruise could be maintained was somewhat limited, the term "cruise" <usually> refers to operating in the lean fuel setting more than the ability to sustain such speeds for extended periods. Niether plane could really sustain such a cruise for more than 20-30 minutes as that was the limit of their fuel anyway (cruise speeds are substantially lower with an external tank). Sustainable cruise speeds were more in the 330 mph range.

=S=

Lunatic

[DerAdlerIstGelandet]

Agreed to this post. Perforamance whise the Spits and the 109s were closer than a lot of people think. Each had its own advantages and disadvantages though.

[alejandro_]

Yes, the data I found didn't make any reference to the conditions for these speeds to be achieved.

Lunatic

I noticed that in some of your posts you refer to the MW-50, saying that it is only used in climb for extended. According to many sources, the Bf-109 pilots would escape on a dive making use of it. I had never heard about the 2 minuts limitations when operating at high speeds. Also, it was not recommended follow the Bf-109 in a dive at less than 3000 meters. The tests posted in another thread specified that the elevators had to be trimmed, but I don't know how this would affect the combat performance. Seconds needed to prepare the elevator? pilot attention to the controls?

Finally, you have any more info regarding the use of WEP for more than 5 minutes in the Mustang and late Spitfire?

Regards.

[DerAdlerIstGelandet]

I concur with what you just wrote. I too have never seen anything saying that a 109 would overheat after 2 min of run time. Maybe Erich who Falkeinz would have some info on this.

[KraziKanuK]

Early 109s using MW boost had a low time limit of usage.

[DerAdlerIstGelandet]

Yeah but that the engine would overheat after 2 minutes?

[wmaxt]

Originally Posted by DerAdlerIstGelandet

Yeah but that the engine would overheat after 2 minutes?

Power adders, like these, can cause local overheating, 2 minutes is not unreasonable. Consider power adders are by definition almost always beyond the original design of the basic engine/cooling system.

wmaxt

[alejandro_]

Krazinuk

Early 109s using MW boost had a low time limit of usage.

Any more info? I am really curious about this issue because I had never come across this problems and many people I have argued with point it out as a major advantage versus Spitfire XIV or P-51D.

Regards.

[Soren]

MW-50 was usually limited at 10min, I don't know where this 2min figure has derived from.

And in comparison to the Bf-109K-4`s 10 minute limitation of running at maximum power, the Griffon 65 engine of the Spitfire XIV was limited to mere 5 minutes of running at maximum power.

Also the 109K-4 had a max continuous cruise speed of 400mph, and it was NOT limited. For the lowest possible fuel consumption, this figure would offcourse be lower.

[Lunatic]

Originally Posted by Soren

MW-50 was usually limited at 10min, I don't know where this 2min figure has derived from.

And in comparison to the Bf-109K-4`s 10 minute limitation of running at maximum power, the Griffon 65 engine of the Spitfire XIV was limited to mere 5 minutes of running at maximum power.

Also the 109K-4 had a max continuous cruise speed of 400mph, and it was NOT limited. For the lowest possible fuel consumption, this figure would offcourse be lower.

Two minutes was the maximum time the 109G6 was capable of full power operation in level flight, according to the Soviets. Yes MW50 could be used for 10 minutes - in a climb. However, at full level speed overheating became an issue. I'm not sure if this was resolved or not in later 109G and K models. Actually, I believe the 109K had enough MW50 for four 10 minute WEP sessions, with 5 minutes at normal power being required between sessions?

The 5 minute limit on the Griffion (and Merlin) was really just a manufacture recommendation - there was no limit to its use. There were many cases where pilots exceeded this by a large margin. I think there is a pilot quote where he was running from the Germans and said he'd been at WEP for 10 minutes and wasn't about to back off the throttle.

Actually the figure I've seen for the 109K-4 is 390 mph max continous cruise, but it could only maintain that speed for about 20 minutes before running out of fuel (after climbing, dropping ext tank, and leaving enough to land). And to get that cruise speed it had to be high (thinner boundary layer and colder air). To get it's 45 minutes of patrol time (after dropping tank) it needed to cruise much slower. The 390 mph cruise is done at a relatively rich setting - German fuel was not so bad in the rich condition, but it was really poor in the lean condition.

=S=

Lunatic

[the lancaster kicks ass]

there you go lunatic, we welcome posts like that!

[Soren]

Two minutes was the maximum time the 109G6 was capable of full power operation in level flight, according to the Soviets.

Seriusly would you rely on Soviet data for any U.S. a/c ? no.

Yes MW50 could be used for 10 minutes - in a climb. However, at full level speed overheating became an issue. I'm not sure if this was resolved or not in later 109G and K models.

Must have been, cause the 109K-4 "Handbuch" mentions NO such limits at all.

Actually, I believe the 109K had enough MW50 for four 10 minute WEP sessions, with 5 minutes at normal power being required between sessions?

Four 10min sessions ?!

No it was only 2½ 10min sessions im afraid The 109K-4 carried 26min worth of MW-50 fuel. (75 L.)

Actually the figure I've seen for the 109K-4 is 390 mph max continous cruise, but it could only maintain that speed for about 20 minutes before running out of fuel (after climbing, dropping ext tank, and leaving enough to land). And to get that cruise speed it had to be high (thinner boundary layer and colder air). To get it's 45 minutes of patrol time (after dropping tank) it needed to cruise much slower. The 390 mph cruise is done at a relatively rich setting - German fuel was not so bad in the rich condition, but it was really poor in the lean condition.

And just where did you acquire these figures ?