Messerschmitt Bf.109 Performance Chronology

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601E run with B4 and the powergraph
 

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The german specification of C3 fuel was 100 Oktan, due to different/less reliable testing methods by the allies it's often stated as 96-97 octane.
The DB 601E was not designed for C3 fuel, it was always a B4-fuel engine. Take-off power was to be 1350 PS but this wasn't available from the start of the Bf 109 F-4 series. The restricted take-off power (one step back to climb&combat 30min rating) was ~1200 PS. Rated alt for this engine was 4.8 km for take-off power, power available was ~1330 PS according to engine power chart. 30 min rating was ~1200 PS at 4.9 km.

It may be possible the initial DB 601A with old supercharger was classified as A-0 but I have never heard of an A-0 in a Bf 109E. Most likely the new supercharger was introduced during production and refited to older aircraft, retaining the 601A-1 designation.
 

Denniss and Juha covered the DB-601E.

You can get some data about the DB-601N and the Bf-109F1/F2 here Basically, the 1st examples of the 601N have been able to make 1175 PS on 2600 rpm and 1.35 ata (for 1 minute), altitude 4900 m. Used on some Bf-109E and 109F-0?
The variant used on the Bf-109F-1/F-2 introduced a new supercharger, the max boost went to 1.42 ata at altitude unknown to me (4500-4900 m?), the limit was now 3 minutes. Difference in power was 94% against 100% for the new engine version (that still bares the same name), that works to about 1250-1260 PS at rated altitude (4.5 - 4.9 km?).
In case over-revving was used ( 2800 rpm), the speed gain was further 10-15 km/h.

More about the data covering the DB-601N, 601E, and Bf-109F can be read at Kurfurst site.
 
The US Octane test is not in any way less reliable than German testing. If you want to compare US fuel to German fuel, then you should test both to the same standard test methodology. C3 tested at 96 Octane in US tests that were used to rate US fuels.

If you wan to use the German rating, that is fine but you'd have to test US fuel with the German test methodology to get a meaningful number for comparison. We HAVE a meaningful number ... 96. That means in our tests the German fuel at the lean rating was about 4 point below US 100 / 130 fuel. So in the German test methodology, the US fuel would likely come out to a performance number of 104 or so in the lean condition.

The US rating in no way suggests C3 was "low grade fuel," it merely gives a number for comparison purposes using the same test methodology as was used to grade the US fuels.
 
The 601N engine is somewhat mysterious, some claim the 1175 PS rating was never available in the 109E with the initial 601N engine, the 109F got the improved 601N and 1175 PS was available from the start. Over-reving was always possible with the 601N but only above critical alt (if I remember right)
 
In most of the very many references I've seen over the years that engine is variously quoted as 1,175 HP or 1,175 PS, mostly PS.

I didn't ever think the very early Bf 109E's had that power, it was more like the E-3 or E-4 and later, up until the next bump in PS.

It seems to me as if the engine power and aerodynamics were improved only when the Spitfire improved, and then only enough to regain some parity or slight superiority, and the cycle would start all over again when the British did the same some time later.

Two better-matched antagonists could hardly be imagined.
 
For a better engien power comparison one should always use take-off power at sea level or static power at rated alt with given power level.
Even in older 109E you may find the 601Aa which offered more power on the deck but was only rated for 4km, very late production may (or may not) have switched to the 4.5km supercharger.
The 601N was only installed in some E-4/N , 9x E-6N and multiple E-7/N at the factory, others may have been refitted with them during their upgrade from older E-series standard to E-7 standard.

At least by 1940 Mtt had recognized that more engine power was not that effective transformed into speed gain as it was supposed to be. Windtunnel test showed aerodynamic issues in the frontal area and in the supporting struts of the tail elevators, win was also somewhat lacking for high-speed aircraft. Assuming a clean E-7/N was really capable of achieving 570 km/h often claimed for 601A-powered 109, the 109F was 595 km/h on 30-min engine rating and 615 km/h on take-off power.
 
The RLM was typically confused about which aircraft the 601 N was to be installed in. In May '40 they were expecting 1,000 of the engines by the end of the year of which 350 would go into reserve. They were to be fitted exclusively the Bf 109 F series. Then there was a change of heart and the engine went into the Bf 109 E series, including retro fitting. Then they decided to retrofit the Bf 110 with the engine. Then they cancelled this and so on and so on. Total confusion and this was in 1940.
This is what led to the piecemeal installation of the engine in various types. It's also indicative of how the RLM/Luftwaffe would contribute to losing the war.
Cheers
Steve
 
Hi Gregg, thank you for clearing up the 96/100 octane discrepancy.

Hi Juha, thank you for the graph and the site.

Hi mhuxt, welcome to the discussion. thank you for the graph. I think that one's too hard for me.

Hi Denniss, thank you for the new information. I am going to have to take some time to figure all the input out that everyone has added. I really picked the wrong time of year for this topic. I have two stereo shelves that I have built and I am suppose to be putting the finishing strips on, filler, sanding and painting. I have a new garage door ordered that I am waiting for to come in at Lowe's. The old door is falling apart. And then the most important thing of all this time of year. As soon as it warms up today, my wife and I are heading to the beach.
BUT, I hope to get all this information processed and Post #1 updated today or tomorrow.

Thank you all for the help in putting the timeline together. This is truly a joint effort.

Jeff

tomo, I forgot to mention that the graph you referred to in post # 43 for the DB 601N is the same graph you referred to in post #35 for the DB 601A (DB 601Aa?) with a new supercharger. Did the engines have the same output?
 
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Hello Steve
while agreeding that the RLM changed its mind on 601N bewildering pace it was partly understandably, IIRC at first 109F was a little bit late, so they had surplus 601Ns and had to do something with them and 109E was a natural candidate for them, then they thought that 109E with 601A was still entirely adequate but 110 needed more power to stay truly combative, so they decided to install many 601Ns to them. IMHO a little bit same as in UK with Spit III and Hurri II, at first Merlin XX was thought to power the Spit but then it was decided that Hurri needed more desperately more power to remain combative, (IMHO futile hope in ETO, its time was clearly passed, and when Japanese planes were found to be clearly better than anticipated IMHO the only suitable job for the Hurri was that of fighter-bomber outside ETO were its sturdier construction and undercarriage were a plus) so Merlin XXs were installed to Hurris and Spit had to be content with the cheaper Merlin 45. In wartime production decisions were difficult and all sides had their times of indecisions.

Juha
 
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It's the bewildering lack of decision though. It is evident on just about every topic (not just engines) at every meeting at the RLM throughout the war. This debacle just covers the second part of 1940.

31st May. 601 N to be fitted to new Bf 109 F-1 and F-2s.

7th June. 601 N to be new Bf 109s and Bf 110s.

7th July. 601 N to be used exclusively for Bf 110. Installation on Bf 109 to be stopped mid production.

19th July. Stocks of 601 N to be used to convert Bf 110s already in service. No further conversion of Bf 109 Groups. New Bf 109 Fs to have 601 N.

26th July. Any further conversion of Bf 110 Groups to 601 N engine to stop.

27th September. 4 Bf 110 Groups are to be maintained with the 601 N engine. Of the remaining engines in stock 40 are set aside as a rotating inventory for the zestorer Groups, of the rest 1/3 are held for rotating stock and 2/3 are to be fitted to Bf 109s.

18th October. Production of 601 N allocated for all new production Bf 109 Fs, All new build Bf 110s. 40 new Bf 109 Es, to maintain existing Bf 109 E strength.

6th November. The General Staff asls that 601 N engines be reserved for Bf 109 E production. Two months production of the Bf 110 at Messerschmitt will receive 601 A engines. II./ZG26 and II./ZG76 need not be equipped with the 601 N and can have their engines swopped out for 601 As.

It doesn't end there either. There are further calls to swop the Bf 110 back to the 601 A, related to C3 fuel shortages, at exactly the same time the General Staff is calling for 6 Bf 110 Groups to be equipped with the 601 N !

Cheers

Steve
 
Hello Steve
Yes, I have read that from Mankau's Petrick's 110-210 and 410 book, clearly some delay in 109F production and probably some problems with C3 production, too.
 
Hi Jeff,

I have a good report on the German fuels, but I'm on vacation and will have to get a new PC going when I get home as my high-end laptop died a video death and the replacement card is as expensive as the whole laptop! So, I'm building a tower ... MUCH easier to replace individual items that go bad on you. I'll get back with you around the end of the month when I get home and back up and online again.

Meanwhile, any decent gasoline test will give very good numbers for comparison. HP achieved on a dynamometer is the same ... it may or may not be entirely accurate, but two cars tested on a dyno can be compared with surprising accuracy.

The German fuel tests might give a slightly different numbers for both lean and rich, but two engines tested by the Germans (or any other nationality) will be easily compared with one another. There was nothing whatsoever wrong with German fuels as long as you knew what you were getting, jetted for it, and operated the engine accordingly. Ditto American, British, Japanese, etc. fuels.

I very strongly resist the seemingly popular attitude of thinking the Germans got the same power out of their engines as we did post-war with 130 / 150 grade fuels since, at least near the end of the war, they had a fuel shortage mostly due to inability to deliver it to forward units, and the fuel that WAS delivered was not top-grade fuel. So they got whatever performance could be had from less-than-top-grade fuel. It was less than the optimum, but still quite good. An engine that delivers 1,500 HP on 130 / 150 grade fuel might still deliver 1,380 HP or even slightly more on 100 / 130 fuel, so they were NOT suffering from low-power operation.

A lot of Japanese fuel was 87 Octane for the entire war!
 
CORSNING said:
...

tomo, I forgot to mention that the graph you referred to in post # 43 for the DB 601N is the same graph you referred to in post #35 for the DB 601A (DB 601Aa?) with a new supercharger. Did the engines have the same output?
Click to expand...

Hi, Jeff,
Sorry if I've made some confusion. I'll post the graphs of the DB-601A (with new S/C) and DB-601N (the version that was is allowed for up the 1.35 ata).
DB-601A:



Db-601N:

 
Perhaps "required" is not what you meant to say, but I'll bite anyway.

According to what I've read, they were delivering very little top-grade fuel ... and very little other fuel ... but about equal quantities of the various grades. Therefore of the fuel they had, about 1/3 or so was their best fuel and the other 2/3's was of lower grade ... still good fuel but not the best in performance number.

When you get about 2/3's of your fuel at less than top grade, then your average plane is not running the top-grade fuel. Some are, but not most. There is nothing wrong with grade 100 fuel unless your engine needs 130/ 150, then the engine cannot be run at full allowed boost for the specified fuel or detonation will occur. Most Merlins today cannot be run at wartime boost levels because they are running grade 100 fuel instead of 130 / 150.

I am away from my dead PC at the moment and don't have all my reference material available, but that is a general summary of what I have seen.
 
The relative volumes of production of the two grades cannot be accurately given, but in the last war years the major volume, perhaps two-thirds (2/3) of this total has the C-3 grade. Every effort was being made toward the end of the war to increase isoparaffin production so that C-3 volume could be increased for fighter plane use.

Technical Report 145-45 - The Manufacture of Aviation Gasoline in Germany

Most Bf109s used B4 fuel. The BMW801 of the Fw190 required C3 fuel. There was about equal numbers of each in Luftwaffe service, late war.
 
I am going to attempt to decipher the new graphs along with the information everyone has supplied. To me it looks like this.
The DB 601N (according to the graph) had the following abilities:
1,175 PS/T.O., 1,255 PS/2,100 m, 1,170 PS/6,900 m. all at 1.35 ata boost.

The DB 601E in the Bf109F-4 started life with the 1.3 ata boost/2,500 RPM limitation: 1,200 PS/T.O., 1,285 PS/2,100-3,400 m, 1,050 PS/6,000m.

The DB 601E later (NEED DATE) was cleared for 1.42 ata boost/2,700 RPM: 1.350 PS/T.O., 1,440 PS/2,100 m., 1,325 PS/4,800 m.

If this is all correct, Denniss do you have a date stating when the 1.42 ata was cleared for the DB 601E?

Jeff
 
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