Bf 109F-4 performance thread

[GregP]

If I could verify they are actual data sheets, then they're fine. If I could get the test conditions, that would be better. If I could verify they're for production, line-ready aircraft, that would be the best. I can type up a data sheet and make it look pretty authentic, Doesn't make it authentic.

I have no notion other nations report falsely, I simply have little way to verify they are, in fact, authentic datasheets. Doesn't mean they aren't. Means I don't know that at this time. There is nothing wrong with German, Russian, Japanese, or any other data.

I never said they were false, I said I have little confidence in the data until I can verify the test condition and the aircraft configuration being tested.

 

[Juha2]

Hello Tomo
thanks for the info on British figures!

But I didn't get what you meant with this:

Not negligible - 13 km/h, circa 8 mp/h.

 

[tomo pauk]

My bad math ☺
The actual difference being as grest as 10 mph for the Finish 109G-2.

 

[CORSNING]

Tomo, I love you man (in a manly way sir). Thank you for posting all the site listings of the
F-4. I do have them in my files. I will have to pull the information out and have a closer
look. If it is warranted, I will have to add it to my listing over at Warbirdsforum.
Mad Dog, Thank you also for your contributions.

To every one else, thank you for adding such great input.

You guys are the best, Jeff

 

[GregP]

I must thank you, too, Tomo. Really great stuff.

I'm sure it's all good, and is a super addition to the data files. You come up with the best data and from sources I can't seem to find. It's little slices of stuff I've been looking for for years. Kudos.

 

[tomo pauk]

Thank you for the compliments, people.

Ironically enough, Juha's comment about German tests, that might not take into account the compressibility effect as early as 1941-42, kinda shook my confidence on the data I was so eager to post. Not just because of that, I'd love to see the horsepower figures for the Allied speed figures re. 109F-4.

 

[Shortround6]

I am guessing that you are not going to find any or they are going to be rare.They could record RPM and Boost settings for a given speed but converting those to power requires running the engine on a Dynomometer which means pulling the engine from the aircraft, installing on appropriate test stand, rigging suitable coolant and oil supplies ( and variable pressure intake air to mimic altitude) and running tests. Once they KNOW the power ratings for those conditions they can use them to figure into the flight test results (maybe).
On occasion captured engines were run on test stands but finding those test results and combining them with flight tests is going to be difficult.
How much allied intelligence depended on captured documents vs extensive testing of captured equipment I don't know.

Some American radials had torque meters built into the reduction gear case and direct measurements could be taken in flight.

 

[Greyman]

Made a chart:
EDIT: added a faint Spitfire Vc running +16 boost bringing up the rear for illustrative purposes.

 

[Juha2]

Hello Greyman
thanks a lot for the chart!
A good idea to put also the speed graph of Spit Vc, it showed how much slower it was than Bf 109 F-4.

I bit OT, British calculated after their Bf 109 G-2(Trop) flight tests that the max speeds of a standard Bf 109 G-2 were 395 mph at 22,000 ft and 328 mph at S.L. The max boost was 1.30 ata.

Juha

 

[Greyman]

... it showed how much slower it was than Bf 109 F-4.

Kind of illustrating what I was getting at in the other thread; "One of the main reasons I don't really go with the high-end German figures I've seen (410 mph, 416 mph) is that I would think if the 109F-4 was truly 50-60 mph faster in service than the Spitfire V, we would see constant mention of that by the Allied pilots."

Tropical Spitfires are even worse off. I think the RAF would have been thoroughly demoralized if these figures, the high-end ones anyway, were 'correct'. I haven't read many anecdotes of Merlin 61 Spitfire IX pilots that note a 109F's 25-35 mph speed advantage up to 26,000 feet. Or no speed advantage in a Merlin 66.

Now that's not to say there was some grand German aircraft performance conspiracy or deliberate deception plan. I just think it's a matter of different countries and different organizations using different methods of calculation. Consider what the AFDU noted in their Thunderbolt report (via wwiiaircraftperformance.org):

Since the P-47C has not been through the hands of the Performance Testing Flight of the Aeroplane and Armament Experimental Establishment, some careful check flights were made at this Unit to obtain an approximate idea of its performance. The figures set out below and on the curve shown at Appendix 'A' have been agreed with Headquarters, VIII Fighter Command, U.S.A.A.F., but can only be taken as approximate. In an independent trial the U.S.A.A.F. obtained slightly higher figures, possibly owing to the difficulty of reading the Standard American airspeed indicator and to the different methods of reduction. At this Unit the British Performance Reduction Methods for Modern Aircraft (A.&A.E.E./Res/170) were used.

I'd be willing to bet Messerschmitt AG. Augsburg didn't use "British Performance Reduction Methods for Modern Aircraft (A.&A.E.E./Res/170)".

And that could just be the start of the differences.

 

[tomo pauk]

We know for sure that plenty of US aircraft tested in the UK didn't quite managed to equal the claimed performance numbers, the greatest offenders being P-39 and P-40.

Problem with data for the 109F-4 is that we don't know when or was the compressibility taken into account (it will be a factor above 350 mph, let alone around 400 mph), and, as it was the case with Fw for the Focke Wulf 190A-2 to A-4, the manufacturer (MTT in this case) might list the optimistic figure as the real one.

 

[GregP]

Greyman's observation that the pilots of the time didn't mention the great speeds difference plays a big part in my thinking, too. They DID mention the performance disparity when they first encountered the Fw 190, so I expect they'd have jumped all over the Bf 109F had it actually been that much faster.

I conclude, reasonably in my estimation, that while a few might have been during testing, the rank and file service Bf 109F actually on the line wasn't.

 

[CORSNING]

Tomo and Gentlemen,
I have looked over all the information of all the sites referenced to
in this thread. I then went back over all the information I have posted
on the warbirds forum. I then went to my files and pulled all the info
I had.
I have come to a conclusion based on all the information at my disposal.
I should also add that while I have what I would consider an excellent
library & files on the Focke-Wulf (by no means complete), my library on
the Bf.109 is somewhat limited IMO.
OK, with all that BS out of the way I have to decline using the performance
the graph titled Vergleich (comparison) Me 109-FW 190 contains.
It does mention 'achieved values = calculated. It does not give a date or
power setting of the engine to achieve these values. IMO it is not real
clear on what values were achieved and what values were calculated.
The author of Beim-Zeugmeister, while very informative, seems to be
very opinionated.
In conclusion, if you view warbirds forum: the great planes AIRCRAFT
PERFORMANCE section, you will notice that I did not use North Americans
calculated graph to post the P-51H's 487 mph top speed figure. I did post
the P-63D maximum speed figure at 450 mph. but only because there is
no official performance test stating otherwise. And I am pretty sure I
labeled it CALCULATED PERFORMANCE.
It all boils down to, give me some official concrete information and I
will gladly add it to AIRCRAFT PERFORMANCE.
, Jeff

 

[tomo pauk]

...

I'd be willing to bet Messerschmitt AG. Augsburg didn't use "British Performance Reduction Methods for Modern Aircraft (A.&A.E.E./Res/170)".

And that could just be the start of the differences.

Come to think about it - when the Americans started accounting for compressibility?

...
The author of Beim-Zeugmeister, while very informative, seems to be
very opinionated.

Not just that, he mis-translates and/or mis-represents some notes. For example, here, he transcribes the note 'z. Zt.' ('zur Zeit') as 'at this time', without the important 'gesp.' abbreviation - 'zur Zeit gesperrt' means ''blocked at this time'. Meaning that Notleistung (2700 rpm and 1.42 ata = 1290 PS at rated altitude, 1350 PS for take off) is still banned as of 29th Nov 1941. Then it is not suspicious to him that 109F-4 does at restricted power as much as 660 km/h??? Kurfurst at least notes that these figures seem not being corrected for compressibility.

... I did post the P-63C maximum speed figure at 450 mph. but only because there is
no official performance test stating otherwise. And I am pretty sure I
labeled it CALCULATED PERFORMANCE....

The P-63C, even when looking at Bell data only here, seem to be around 425 mph. It will fall on the shoulders of the P-63E, with it's a bit improved engine, to came close to 450 mp/h.

 

[CORSNING]

Yes Sir, you are absolutely right the 450 mph figure should
go to the P-63D and possibly later P-63E. My mistake.

Nice catch Tomo, Jeff

PS: P-63C maximum speed is in the 424-434 mph. range.

 

[GregP]

Hi Corsning,

Your collection of performance information is amazing, and I agree that calculated performance, while interesting in its own right, should be separated from actual flight test performance.

One is achieved, and one is a good estimate.

Also, we need to know the test conditions. If you fly with no ammunition, a waxed finish, a freshly-tuned engine, 40% fuel, and no shackles or extra tanks, you SHOULD get sparkling performance. But it isn't really representative of a combat-configured aircraft.

 

[CORSNING]

Hi Corsning,

Your collection of performance information is amazing, and I agree that calculated performance, while interesting in its own right, should be separated from actual flight test performance.

Thank you for the recognition Greg. It took me many years and thousands of hours of research
to put that together. It is far from complete but with each new find it becomes better.

One is achieved, and one is a good estimate.

It is very important to note this when posting information.

Also, we need to know the test conditions. If you fly with no ammunition. a waxed finish, a freshly-tuned engine, 40% fuel, and no shackles or extra tanks, you SHOULD get sparkling performance. But it isn't really representative of a combat-configured aircraft.

This is of the utmost importance when trying to compare aircraft to aircraft equally.
I am a very adamant believer of this. If I have failed to list conditions on any of
my posting, I apologize. And if pointed out, I will be glad to correct.

 

[Kryten]

So is there any clarity if the 109f4 figures are corrected, as they look rather dubious at present?

 

[Greyman]

Hohun/Mr.Ruch did work on that front a while back, and broadly, his results (at 6,283 lb) were similar to if you took the green '42 Datenblatt curve and scooched it back 5-7 mph.

 

[CORSNING]

Kryten,
I am going to stand by the information I have posted:
MESSERSCHMITT Me 109F PERFORMANCE - Aircraft Performance - The Great Planes : World War Two Warbirds
as the absolute best quick, readily comparable performance
on the web at this time. However, I would like to add that it is
very incomplete and is in need of some serious additions.
If that is not the answer you are looking for at this time, my
answer is; I'm working on it.