Inaccurate performance data for BOB fighters in COD comparing to RL data

[winny]

Originally Posted by Crumpp

Interesting but you cannot answer operational questions with logistical answers.

If you compare the fuel at the airfields in September 1939 with the strategic reserves of 87 Octane you can get an idea of the ratio's they used.

Usually it is about 40:1 between Strategic Reserves and point of use. 16,000 tons at the airfields in September thru November 1939 leaves us ~8,000 tons per month.

Strategic Reserves of 87 Octane from 31 August 1939 to 7 December 1939 is (323,000 + 309,00)/2 = 316,000 tons

316,000 tons / 8,000 tons = 35.5

Now, they will maintain that ratio as best they can. It represents the 18 weeks of fuel in reserve.

So with 146,000 tons of fuel, roughly 3825 tons was usable. Now that 8,000 tons per month is training and administrative flying, not operational. When the war starts, 3825 tons is less than a quarter of the fuel required to conduct operational, training, and administrative flying.

Anyway, it is interesting but not applicable because it is logistical documentation and not operational.

Absolute rubbish. I posted these documents in response to the repeated claims made that there was a shortage of 100 octane fuel. There wasn't.

So, you're saying that the British sat on over 100,000 tons of fuel because they needed a reserve? When the threat of invasion was looming...?
.

For operational documentation see the combat reports.

[Kurfürst]

Originally Posted by Glider

I don't deny that this is interesting but your still looking at the wrong paper. Its also interesting that they were only used in me110 and Ju88 aircraft which were outclassed in combat when fighting spitfires and Hurricanes. So the Luftwaffe may have had some but it didn't have an im pact on the fighting and clearly it was in small numbers.

Its the a different paper, same series of reports. I think its unnecessary to debate this any further.

As for the use of 100 octane, initially it was used by 3 Wings of 110s and 1 Wing of 109s (JG 26). The British quite simply did not found samples of 100 octane in downed 109s, which is not surprising considering they only got a couple of dozen samples. The fact that some Ju 88s were also running on 100 octane were found is interesting, considering that they would be unlikely to benefit from it at all. I would agree it did not have much effect on the fighting, save for the 110s. The stock 109s already had more than enough performance.

As for outclass, I would disagree. Looking at the increase of output from the 601N, I would estimate that 110 could do about 550-560 kph at altitude, ie. as fast as Spitfires and much faster than Hurricanes, 109E with the 601N were likely to get about 590 kph - much faster than anything else out there at altitude.

110s had priority initally, in the automn a 4th Gruppe was converted to 601N/100 octane. 109s at first were limited to one Gruppe (wing), then it October it was decided that they should get priority for 601Ns.

The complete story is described in the General of the Luftwaffe meetings by Mankau and Patrick, which I summerized briefly recently:

Currently Il-2:COD does not model the Luftwaffe's 100 octane fighters. These were equipped with the DB 601N in Bf 110C and Bf 109E, and hence received the suffix of /N to their designation (ie. Bf 109E-4/N, E-5/N, E-7/N etc.)

DB 601N powered variants appeared since July 1940, the start of the Battle. Approximiately half the Bf 110C and one Gruppe (Wing) of Bf 109E was using the 100 octane engine during the Battle, so the numbers, especially 110 were significant.

The 100 octane units can be identified as the following: III/ZG 26, Erpobunggruppe 210, II/ZG 26, II/ZG 76, one Gruppe of JG 26.

The DB 601N featured increased ratings and altitude performance. It ran on the Luftwaffe's C-3 fuel, of 95 (lean) and 110 (rich) performance. The 601N entered production in the end of 1939.

Power curve for DB 601N as installed in Emil (Bf 109F version had more powerful supercharger)
http://imageshack.us/photo/my-images...ercurvebw.jpg/

100 octane use in the Luftwaffe during the Battle of Britain:

On the 12 July 1940 General der Luftwaffe meeting, it was noted that DB 601N engines are to be installed primarly into Bf 110s, then its followed in the serial production Bf 109E.

On the 19 July 1940 General der Luftwaffe meeting, it was noted DB 601N engine are installed in frontline Bf 110s. So far 1 Gruppe of Bf 109E was fitted with the new engine. The Bf 109F entering production is also using the 601N engine.

On the 26 July 1940 General der Luftwaffe meeting, the General Staff requesting more Bf 110 to be fitted with DB 601N. Decision would be made in the end of August 1940.

On the 9 August 1940 General der Luftwaffe meeting, it was noted that 3 Gruppen of Bf 110 and one Gruppe of Bf 109 was fitted with DB 601N. Increased installations require increasing the reserve of DB 601N motors.

On the 30 August 1940 General der Luftwaffe meeting, it was noted that for 280 'active' DB 601N motors, the no. engines in reserve is to reach 180.

On the 27 September 1940 General der Luftwaffe meeting, it was noted that the Chief of Staff decided that 4 Gruppen of Bf 110 is to be fitted with 601N and the number to be maintained. 1/3 of the remaining DB 601N engines is to be reserved as replacement engines for frontline units, and the remaining 2/3s are to be released to be installed in Bf 109 aircraft.

On the 18 October 1940 General der Luftwaffe meeting, it was noted that apart from the already present 1 Bf 109 Gruppe with DB 601N, no more is possible to be equipped. Existing DB 601N are required by: 1, New production Bf 109F 2, New production Bf 110 delivered by Mtt AG as replacement to the existing 4 Bf 110 Gruppen with 601N 3, 40 replacement Bf 109E (conversions) to maintain the strenght of the 1 Bf 109 Gruppe with 601N. 5, Replacement/reserve engines for 1, 2, and 3.

On the 26 October 1940 General der Luftwaffe meeting, it was noted that by the end of October, 1100-1200 DB 601N engines were delivered, and were used for the 4 Gruppen of Bf 110 and one Gruppe of Bf 109 equipped with DB 601N, and to maintain these units with replacements, and furthermore to recon units under Luftwaffe High Command. The remaining engines are used for Bf 109F-1, F-2 production. 130 engines were reserved for circulation (replacement). All Bf 110s produced, apart from the DB 601N equipped ones by Mtt AG are to be directed to maintain the strenght of 120 of night fighter units.

On the 6 November 1940 General der Luftwaffe meeting, it was noted that General Staff requested all DB 601N engines to be installed in Bf 109E. In order to free up engines, 2 months worth of production (November, December) of Bf 110s produced by Mtt is to engined with DB 601A instead of 601N. 601N engines are to be distributed: 1) Final production series of Bf 109E 2) Replacement engines for III/ZG 26, Erpobunggruppe 210. If 601N engines are not available in sufficient quantities, the following Gruppen can be given 601A as replacement engines: II/ZG 26, II/ZG 76. As the production of 601N in January 1941 will be considerably greater, Bf 110 production shall switch completely to 601N.

On the 22 January 1941 General der Luftwaffe meeting, it was reported that on 1 January 1941, the following number of DB 601N engines were installed in frontline aircraft.

in Bf 109s
Bf 109E-1 : 16 pcs, Bf 109E-3 : 1 pc, Bf 109E-4 : 54 pcs, Bf 109E-6 : 1 pc, Bf 109E-7 : 34 pcs, Bf 109E-8 : 2pcs. Bf 109F-1 : 5 pcs.
Total 112 Bf 109E with DB 601N present in service, plus 5 Bf 109F.

in Bf 110s
Bf 110C-1 : 4 pcs, Bf 110C-4 : 40 pcs, Bf 110C-5 : 12, Bf 110C-7 : 14 pcs, Bf 110D-0 : 18 pcs, Bf 110D-2 : 20 pcs, Bf 110D-3 : 8 pcs, BF 110E-1 : 176 pcs, Bf 110E-2 : 14 pcs.

Total : 306 engines, ie. 153 Bf 110s with DB 601N present in service.

in Misc. types
He 111P : 8 pcs, Do 215 : 68 pcs.

By 1st April, the following conversion to DB 601N is planned: 6 Gruppen of Bf 110 = 480 engines, 5 Gruppen of Bf 109E-7/N = 200 engines, 12 Gruppen of Bf 109F = 480 engines, 'Rowehl' = 70 engines. This means by 1 April appx. 850 DB 601N engines will be in active operation.

etc.

Source: Pages 24-29 in Heinz Mankau/Peter Petrick : Messerschmidt Bf 110, Me 210, Me 410. Aviatic Verlag, 2001. ISBN: 392550562

Originally Posted by Glider

But when the DB 605 was first built it was for B4 not the C3 fuel, different versions of the engine were built for the different fuel and for most of the war the 109 normally used B4.

Yes, more or less so. We have discussed that beforehand. The 601E in mid 1941 already reverted to 87 octane B4, but it developed a lot more power - ca. 1400 HP - than the 601N on 100 octane. Apparently, the 601E was a superior design.

The 605A series built on the 601E and continued with 87 octane. They were held back by technical difficulties with the oil system, but still, when these were fixed could produce 1475 HP at takeoff on 87 octane. A different 605, the 605D was tried for 100 octane but it was only good for a marginal improvement, 1550 HP, so I guess it was not worth it. At the same time the Germans decided that 100 octane is the way for the BMW 801D series, and all FW 190A run on 100 octane.

The Merlin was a different story, at 27 liters it could not hope to compete with the 35 liter DB / Jumo engines without high boost and high octane fuel, heavy supercharging and the resulting need for a bulky intercooler installation. An interesting comparioson is the late war DB 605DB, which even at low boost had the performance of the two stage Merlin 6x series, without 100 octane, without an intercooler and without water injection.

The Germans could produce any number of high grade fuel, it was a matter of pressing B4 stock through another chemical process as far as I understand. It wasnt needed. Why use a more expensive fuel for the same results?

In short, high octane fuel was critical in development of the small displacement Merlin and not critical at all for the DB or Jumo engines. Despite that, the sources I have point that 100 octane fuel was used by the Luftwaffe in 109G, He 111H even when this was unnecessary - a sort of luxury in war, but it probably eased logistics.

Originally Posted by Glider

There is a difference and its a large one. All my statements are supported by documents which are posted. However you failed and you did admit to me that you hadn't tried the Australian Archive the one place that was supposed to have it.

We do seem to disagree in the analysis of those documents. I believe the documents you have posted clearly point to a limited issue of 100 octane to select fighter units, which was eased in August but did not materialize until the end of September 1940. Which means plenty of FC Sqns were still flying on 87 octane and corresponding limitations.

FYI I did ask Pips years ago but since he didn't have the reference handy, and the paper is not digitalized yet, so unavailable for online search (which I did), so I see no point. Its impossible to find a paper without a proper reference, simple as that.

Originally Posted by Glider

You have his details, send him an e'mail, then you will know, thats what researchers do isn't it, check facts?

I have all the facts I need. Whoever he is, he has discredited himself in my eyes. He is incapable of academic discussion, unable to support his claims, and making up bogus claims. he makes up for that with evasion and petty arrogance. In short, a waste of my time.

I should add that he also appears where I appear. He hasn't misrepresented any facts and you don't have the paper you claimed to have, i.e. the one up to October 1940 which he was quoting from. In other words the misrepresentation, is yours, not his.

Unfortunately its not true. He claimed the only high octane fuel used and found by the British was of British origin. As the papers I have shown, this was not the case. The Germans used plenty of 100 octane of their own making.

He was wrong, and his research was amateurish, or deliberately presented false information.

I have offered three times for you to tell me which paper you are talking about and if I don't have the entire paper, I will get it for you next week when I go to the NA, this offer is still open until Monday, call my bluff.

I am talking about AVIA 10/282 I believe, the one you have posted excerpts from, ie. the August 1940 decision to authorize 100 octane fuel for all operational aircraft, the note that the fuel was issued to the 'units concerned' in May etc. If you can post this paper in its entirety for the whole of community to decide its contents for themselves, I think it would be mighty helpful and please accept my gratitude in advance.

No I am not. I clearly said that I didn't know but it made sense to use the 100 Octane as well as German fuel. Nowhere did I deny the use of German use of 100 Octane. Please post where I said what you claim, if you cannot then at least read my posting before replying.

Well we are in agreement then - isn't that a wonderful thing? I am sure the LW used British 100 octane, courtesy of the RAF after Dunkerque, to its benefit. Its a bit ironic isn't it. Additionally, the LW captured large stocks of French avgas. And, of course, it had its own domestic supply of 100 octane as per German specs.

My point was to point out the unsustainabilty of any partisan thesis about that the sole use of captured British stocks.

I believe this to be the case but believe that my case is a strong but not perfect one. Again I repeat that I have never said that the Luftwaffe didn't use German 100 octane.

We have to agree to disagre here. For my point of view, there are too many flies - Pips papers, the note of Squadrons concerned and the lack of any paper saying universal use amongst others- in that ointment to make it believable. That being said, of course the RAF was using 100 octane for a fair number of fighter Squadrons, and for this reason a 100 oct / +12 boost variant is fully supportable for COD. Hence I supported Osprey's poll in the bug thread, despite his often petty and malicious contents. I just disagree that this should be the only variant modelled. I think a 87 octane version should be there as well, and mission builders / server hosts will decide what they would believe to be true.

His calculations have a far more logical set of assumptions than yours, but you are correct, I don't rely on calculations.

I don't consider simplistic and wishful calculations, that ignore the needs of bombers, non-operational flights, engine testing etc. completely. But we do agree that primary sources should be the basis of any conclusion.

[Kurfürst]

Originally Posted by Osprey

You make me laugh Crump. You are 'special' aren't you!

As far as I am concerned, Crumpp has technical and practical expertise, being involved in the restoration of a WW2 Fw 190, and practical piloting experience to boot.

On the other hand, you are kid with none of the above. If I just weight the two against each other, you don't came out very well.

[Crumpp]

Absolute rubbish. I posted these documents in response to the repeated claims made that there was a shortage of 100 octane fuel. There wasn't.

Winny,

A shortage can be the result of any number of things. Yes, there was a shortage because the Strategic reserve to production ratio is just not where it should be.

In fact, that shortage continued almost throughout the war and is the subject of several meetings in the United States about 100 Octane production. That does not necessarily mean aircraft were feeling a shortage. It does mean the strategic reserves are short. Remember, they originally wanted 800,000 tons in reserve before a single operational aircraft used the fuel. Of course there is a shortage!!

Great example of why looking at strategic logistics is a horrible method to predict operational conditions is the German late war fuel situation on the western front. Strategically, Germany had plenty of fuel in their reserves. The shortage was at the operational side due to main supply route bottlenecks caused by allied airplanes shooting up the stockyards, railheads, and trucks!

[41Sqn_Banks]

Here's the page from the "June, 1940" Pilot's Notes that specifies the fuel (which actually is from "May, 1940" as can be seen in the "List of Content" of Section 1).

[Seadog]

Originally Posted by Kurfürst

I
As for outclass, I would disagree. Looking at the increase of output from the 601N, I would estimate that 110 could do about 550-560 kph at altitude, ie. as fast as Spitfires and much faster than Hurricanes, 109E with the 601N were likely to get about 590 kph - much faster than anything else out there at altitude.

So now the story changes to "our 100 octane gave better performance than your 100 octane" when Kurfurst knows full well that only a handful of 109Es used 100 octane, versus the entire RAF FC while the 110 got slaughtered no matter what fuel it used.

In Adolf Gallands own words while speaking to Goering:

Finally, as his time ran short, he grew more amiable and asked what were the requirements for our squadrons. Moelders asked for a series of Me109's with more powerful engines. The request was granted. 'And you ?' Goering turned to me. I did not hesitate long. 'I should like an outfit of Spitfires for my group.'

[Seadog]

Originally Posted by Kurfürst

We have to agree to disagre here. For my point of view, there are too many flies - Pips papers, the note of Squadrons concerned and the lack of any paper saying universal use amongst others- in that ointment to make it believable. That being said, of course the RAF was using 100 octane for a fair number of fighter Squadrons, and for this reason a 100 oct / +12 boost variant is fully supportable for COD. Hence I supported Osprey's poll in the bug thread, despite his often petty and malicious contents. I just disagree that this should be the only variant modelled. I think a 87 octane version should be there as well, and mission builders / server hosts will decide what they would believe to be true.

I have repeatedly challenged you to produce evidence of even a single Spitfire/Hurricane 87 octane operational squadron combat sortie during the BofB. This should be an easy task if, as you contend, the majority of RAF FC Spitfire/Hurricane operational squadrons were using 87 Octane fuel.

So I'll issue the challenge again and again, until you answer it or admit that your contention is unsupported by the historical record.

I'm still waiting for a reply.

[winny]

Ignoring the tit for tat for a moment.

Can anyone tell me if a Merlin that had been converted to 100 could run on 87?

I don't want guesses or in my experience answers.. Please.

The reason I ask is that it appears that in the German machines it was not possible to interchange the fuel. (87 oct B-4 & 100 oct C-3) (Fighter Arm pamphlet Nr.1410144)

Also I recall reading somewhere that a converted Merlin would not run on 87 because of the modifications. I cannot find where I read it though.. Maybe I dreamt it!

[robtek]

Originally Posted by Seadog

So now the story changes to "our 100 octane gave better performance than your 100 octane" when Kurfurst knows full well that only a handful of 109Es used 100 octane, versus the entire RAF FC while the 110 got slaughtered no matter what fuel it used.

In Adolf Gallands own words while speaking to Goering:

A typical biased reply!!!

The difference was in the engines, the 27l Merline needed the 100 octane to compete with the 35l DB601 with 87 octane.
The DB601 with 100 octane was playing in another ballpark and restored the engine superiority until better Merlins appeared.

[41Sqn_Banks]

Originally Posted by winny

Ignoring the tit for tat for a moment.

Can anyone tell me if a Merlin that had been converted to 100 could run on 87?

I don't want guesses or in my experience answers.. Please.

The reason I ask is that it appears that in the German machines it was not possible to interchange the fuel. (87 oct B-4 & 100 oct C-3) (Fighter Arm pamphlet Nr.1410144)

Also I recall reading somewhere that a converted Merlin would not run on 87 because of the modifications. I cannot find where I read it though.. Maybe I dreamt it!

Merlin II/III: Yes

http://forum.1cpublishing.eu/attachm...0&d=1334948575

"100 octane may be used, if the engine has been suitable modified", if it wouldn't be possible it would state "must be used".

Merlin XII: Yes

http://forum.1cpublishing.eu/attachm...8&d=1332086871

It shows different engine limitations depending on used fuel.

For all British engines: Yes

http://forum.1cpublishing.eu/attachm...0&d=1334727256
http://forum.1cpublishing.eu/attachm...1&d=1334727263

Clearly states that it is possible, however the operational limits are lower.