Bf109 test data

[*Buzzsaw*]

Originally Posted by Kurfürst

V15 or V15a? In any case, the V15a tests note a "DB 601A", but they give the rating as 1,35ata (which is the Aa rating). Power ratings also match that of the Aa.

These figures appear to come directly from the Bf 109E operating manual and were clearly for 601Aa. See: http://109lair.hobbyvista.com/techre...als/bf109e.pdf


The answer to both questions is that V15a fully confirmed to serial production aircraft, as the test report clearly notes.

The problem was there were no 109E1's or 109E-3's in production or service at the time V15 was constructed. V15 was clearly a prototype.

According to Uwe Feist in "The Fighting Me 109", published London: Arms and Armour Press, 1993, there were two prototypes built to test the 109 with the DB601: V14, which had two MG's in the nose, and two F/F 20mm in the wings and which was equipped with a DB-601Ao engine, and V15, which had only had the two nose MG's, (no weapons mounted in the wings at all) and which it appears, was equipped with the DB-601Aa engine.

According to Wiki, V14 was determined to be the more successful of the two prototypes, and there was an initial pre-production order of 20, designated E-0. Later, early production 109E's were sent to Spain to be tested with the Condor Legion. Production later commenced with the E-1 variant, with two MG's in the wings.

This information clearly points out the difference between V15 and the later production aircraft. This aircraft did not have the drag or weight of a pair of MG F/F's and their ammunition to contend with. And who knows what else was not present?

The question is, where is the test of V14?

[KG26_Alpha]

Originally Posted by *Buzzsaw*

The problem was there were no 109E1's or 109E-3's in production or service at the time V15 was constructed. V15 was clearly a prototype.

According to Uwe Feist in "The Fighting Me 109", published London: Arms and Armour Press, 1993, there were two prototypes built to test the 109 with the DB601: V14, which had two MG's in the nose, and two F/F 20mm in the wings and which was equipped with a DB-601Ao engine, and V15, which had only had the two nose MG's, (no weapons mounted in the wings at all) and which it appears, was equipped with the DB-601Aa engine.

According to Wiki, V14 was determined to be the more successful of the two prototypes, and there was an initial pre-production order of 20, designated E-0. Later, early production 109E's were sent to Spain to be tested with the Condor Legion. Production later commenced with the E-1 variant, with two MG's in the wings.

This information clearly points out the difference between V15 and the later production aircraft. This aircraft did not have the drag or weight of a pair of MG F/F's and their ammunition to contend with. And who knows what else was not present?

The question is, where is the test of V14?

I would take Luftwaffe data only as confirmed data, Wiki or old books are not always to be regarded as reliable to be honest.


"It clearly points out"................nothing




.

[JtD]

I don't think it is questionable if aircraft's condition is representative enough for a standard 109E. I'd say it is close enough, there are always differences between individual aircraft, even if all of them are brought up to the same specs. Weight is pretty much irrelevant at high speed, and drag from wing installed weapons was shown to be small. I also think the methods employed are sound, and the data is as solid as test data can be.

So far so good, but for me there are other open questions, mostly regarding high altitude performance. It was brought up in another topic - a plane going 500 at SL should manage a lot more than 575 at 5000m, if it has slightly more power available at altitude. Doesn't make sense the way it is. Also, V15 having a DB601Aa engine, the full throttle altitude of 4900m is unreasonably high, no answer found as of yet.

Spitfire tests do not show this kind of problems, which makes it easier for me to accept their results. They are more plausible. OTOH, Spitfire test results usually get less corrections and would therefore be less accurate.

[Kurfürst]

Originally Posted by JtD

I don't think it is questionable if aircraft's condition is representative enough for a standard 109E. I'd say it is close enough, there are always differences between individual aircraft, even if all of them are brought up to the same specs. Weight is pretty much irrelevant at high speed, and drag from wing installed weapons was shown to be small. I also think the methods employed are sound, and the data is as solid as test data can be.

So far so good, but for me there are other open questions, mostly regarding high altitude performance.

I agree.

It was brought up in another topic - a plane going 500 at SL should manage a lot more than 575 at 5000m, if it has slightly more power available at altitude. Doesn't make sense the way it is.

Why? How about +12 Spitfires...? They seem to be claimed to go Thing is, the 601Aa doesn't have more power at altitude, it's pretty much the same at all altitudes.

Here's another take on it. If you look at Spitfire I speeds, roughly 285 mph at SL and about 355 mph at FTH, and the Merlin III's output, you will see that the Merlin has a good deal less power at SL than the DB 601A/Aa (about 870 HP vs 1045 PS).

At rated altitude, the Merlin offers a bit more power, but the two aircraft reach about the same top speed. In short, the 109E needs less power at altitude, which quite clearly points to less overall drag in the high speed regime.

So how on Earth would be it be slower or just as fast than Spitfire with more power (100-150 PS more) near SL...?

[/QUOTE] Also, V15 having a DB601Aa engine, the full throttle altitude of 4900m is unreasonably high, no answer found as of yet.[/QUOTE]

I don't think it's very unreasonable, 1000-1200 m gain in FTH due to high speed rammed power seems fairly typical, and it's seems it is what in all tests agree.

Spitfire tests do not show this kind of problems, which makes it easier for me to accept their results. They are more plausible. OTOH, Spitfire test results usually get less corrections and would therefore be less accurate.

Because we have so few Spitfire I tests.

[*Buzzsaw*]

Originally Posted by Kurfürst

Why? How about +12 Spitfires...? They seem to be claimed to go Thing is, the 601Aa doesn't have more power at altitude, it's pretty much the same at all altitudes.

If you want to open up a discussion of the Spitfire's performance, feel free, but in this post, the subject is 109's. At this point you are only serving to muddy the waters with unrelated material.

I'd like to see the document where V15's loadout is mentioned.

[Kurfürst]

Buzzsaw,

To answer your questions about the V15a, yes its an E-1, but no, I do not think there was any meaningful difference between the E-1 and E-3 aerodynamically. Only the fitted armament was different. Now one of the test you have posted show that there was 0 to 1 kph "difference" between the MG FF being present or not.Other than that there was a slight bulge under the cannon drum in the underside of the wing. I do not know what drag that was responsible for, but I do have British tests for the Spitfire which give a speed difference of a whopping 1 mph for the similar bulge for the Hispano ammo drums...

As for the V15a test, the full paper has been transcribed on my site
http://kurfurst.org/Performance_test...w_109V15a.html

and I have also recently uploaded the originals to this forum, you can find in one of my recent postings in another thread.

As for the 3 papers you have posted, they are turn times and radii for the 109E at 0 and 6000m, at various flap settings.

[*Buzzsaw*]

Originally Posted by Kurfürst

Buzzsaw,

To answer your questions about the V15a, yes its an E-1, but no, I do not think there was any meaningful difference between the E-1 and E-3 aerodynamically. Only the fitted armament was different. Now one of the test you have posted show that there was 0 to 1 kph "difference" between the MG FF being present or not.Other than that there was a slight bulge under the cannon drum in the underside of the wing. I do not know what drag that was responsible for, but I do have British tests for the Spitfire which give a speed difference of a whopping 1 mph for the similar bulge for the Hispano ammo drums...

As for the V15a test, the full paper has been transcribed on my site
http://kurfurst.org/Performance_test...w_109V15a.html

and I have also recently uploaded the originals to this forum, you can find in one of my recent postings in another thread.

As for the 3 papers you have posted, they are turn times and radii for the 109E at 0 and 6000m, at various flap settings.

Salute

Sorry Kurfurst, your answer is clearly not accurate.

Firstly, You have not provided an original document which shows the loadout, weight, or boost levels of the the V15 aircraft. If you have the full test, show the originals, not transcribed incomplete sections.

Secondly, the V15 is clearly not a production aircraft, there were no production E-1's till late in 1938 and early in 1939. The date of the V15 test is April of 1938, long before any E models were produced. V15 is one of several prototypes produced to test the installation of the DB601 engine in a 109 airframe.

Here is a excerpt from 'Messerschmidt Bf 109' by Robert Grinsell. This is one of several sources I have consulted which clearly trace the evolution of the 109E model, and which are in general agreement. The section of relevance, begins with the 109E header.



As the above notes say, V15 was one of three early pre-production aircraft which were built in 1937 and which had the DB-601 installed and tested in various forms. These were V13, V14 and V15. I could not absolutely confirm a picture of V15, but I believe it is one of the lower or upper aircraft on the following page, as no others of this type were constructed. V14, the identical brother aircraft to V15 is definitely identified. You will notice there is no armament installed on V14 or the other two aircraft.



At this time, Germany was orchestrating a propaganda campaign to convince potential enemies that it had a formidable and powerful air force with aircraft which outperformed all opponents. At this time, Germany was potentially moving into a conflict situation over its claims on the Sudetenland and Czechoslovakia. In fact, the latest model of the 109 in service, the 109D, was slower and climbed worse than the initial model of the Hurricane then in service. The Luftwaffe attempted to mislead British and French observers by sending highly modified versions of the 109 to air competitions. Below is a picture of V13 in its initial form during the July 1937 Zurich International competition. In the case of the July event, V13 was equipped with a modified 1560 hp DB-601 engine, (misidentified in the caption as a DB600) which allowed it to win several events. These engines were designed to only last a few hours, used special fuels and boost levels. The Luftwaffe claimed their entries were 'production', in service aircraft, despite the fact no 109's were in service with Daimler Benz engines at that time. No armament was visible.



V14, also equipped with a 1560 hp DB 601, was also present, and flown by Ernst Udet, head of the Technical Office of the Luftwaffe, but it crashed. Below are pictures, again, no armament is visible.



In November of the same year, at a second international air competition, V13 made another appearance, in even more highly modified form. This time it was powered by a more heavily boosted DB601 which produced 1650 hp. This aircraft also had a large number of other modifications, including a special spinner, highly polished frame, and special radiators. And quite obviously, it has no armament. It achieved a top speed of 379 mph/607 kph at sea level. It was claimed to be a production, service aircraft. Seen below:



The aircraft was flown by Dr Wurster, the chief test pilot for Messerschmidt. You will notice that the V15 test also has Dr Wurster as test pilot. During 1937 and 1938 V15 was being used a testbed for various engine, boost, radiator, and oil cooler configurations. It continued in this role through 1938 and into early 1939, then was retired.

According to the several sources I consulted, it is clear this aircraft did not have standard armament, if any, and that it was equipped at various times with highly modified engines.

The fact the results of the posted V15 test are not duplicated by any other of the tested actual E series aircraft is a clear indicator its results were obtained with non-standard equipment.

Sources

'Messerschmidt Bf 109' by Robert Grinsell
'Bf 109, Versions B-E' by Roy Cross, Gerald Scarborough and Hans J Ebert
'Messerschmidt Bf 109' by Heinz J Nowarra
'Spitfire vs Bf 109' by Tony Holmes
'Messerschmidt Bf 109, Owners Workshop Manual', by Paul Blackah and Malcolm V Lowe

[*Buzzsaw*]

Originally Posted by KG26_Alpha

I would take Luftwaffe data only as confirmed data, Wiki or old books are not always to be regarded as reliable to be honest.


"It clearly points out"................nothing




.

Actually, this is not an 'old book', it is not one of Heinz Nowarra's 1960's era collection of misinformation, it is one of the newer generation of published works on the 109. Second, I would take the information of a published author as reliable and only discredit it when primary sources disagree. In this case, the primary sources are incomplete. There are two original pages of the V15 test available, (Blatt 4 and 6)and one page mostly transcribed by Kurfurst, (Blatt 5) with only small sections from the original page shown. None of them includes the weight of the aircraft or the details of the armament or equipment.

Another note re. V15:

As mentioned, neither the 109E1 or 109E3 were in production when V15 was constructed, so it was impossible for it to be modelled on them, they didn't exist. As anyone who has looked at the history of the 109 knows, the 'V' designation indicates a prototype or test aircraft.

[Kurfürst]

Originally Posted by *Buzzsaw*

The problem was there were no 109E1's or 109E-3's in production or service at the time V15 was constructed. V15 was clearly a prototype.

Yes.

Originally Posted by *Buzzsaw*

According to Uwe Feist in "The Fighting Me 109", published London: Arms and Armour Press, 1993, there were two prototypes built to test the 109 with the DB601: V14, which had two MG's in the nose, and two F/F 20mm in the wings and which was equipped with a DB-601Ao engine, and V15, which had only had the two nose MG's, (no weapons mounted in the wings at all) and which it appears, was equipped with the DB-601Aa engine.

We are not discussing V14 (WNr 1029, first flew April 1937) V15 (WNr. 1773, first flew december 1937) but V15a (WNr. 1774). V15a had four MG 17s, as the report notes:

"An Bf 109 V 15 a, der Mustermachine für die E-1-Serie, wurden die Geschwindigkeitsleistungen erflogen. ... 2 Flügel- und 2 Hauben-MG eingebaut."

This information clearly points out the difference between V15 and the later production aircraft. This aircraft did not have the drag or weight of a pair of MG F/F's and their ammunition to contend with. And who knows what else was not present?

Again we are talking about V15a, not V15.

The question is, where is the test of V14?

Good question.

[*Buzzsaw*]

Originally Posted by Kurfürst

We are not discussing V14 (WNr 1029, first flew April 1937) V15 (WNr. 1773, first flew december 1937) but V15a (WNr. 1774). V15a had four MG 17s, as the report notes:

"An Bf 109 V 15 a, der Mustermachine für die E-1-Serie, wurden die Geschwindigkeitsleistungen erflogen. ... 2 Flügel- und 2 Hauben-MG eingebaut."

Where is the page from this report which you are quoting? Please post it here if you have access.

Second, if your quote is accurate, then it is clearly not an E-3 which is being tested, it is an E-1, which was lighter, not having the MG F/F 20mm cannon and ammunition, and faster.

The sea level speeds of the E-1 and E-3 were noted as clearly being different.

E-1: (this is a test a full year later than the V15 test, AND it is of a PRODUCTION 109E-1)



E-3



If you are arguing the 109E-1 should be faster, perhaps to the V15a, (please provide the missing page) then perhaps you have a case, although the above document suggests speed should be higher than the E-3, but considerably less than V15. As far as the E-3 and E-4, many questions remain, nothing has been proved to suggest their speeds should be similar to V15's.