Fw-190 Prototype engine changes

[KrazyKraut]

Are You familar with the BMW-801C MRO intervals? If 100 hours was the desired MRO interval to qualify for operationally reliable engines, then the -801C cannot be considered RELIABLE by 1941, too. Correct me, if Im wrong. The december 1941 state of Fw-190 engine reliability required 25 hours MRO intervals.
Note that the fourth and fifth Db-603 prototypes produced in 1939 running on Water-methanol producing 3000 hp for the speed record car trial abandoned by outbreak of war. By this time, no -801 was even benchtested.

I am aware of the comparison test you are getting your numbers from, yes. But you should keep in mind that it stems from the earlier days of the Fw 190 and no doubt, there was still some scepticism towards the plane. Oh and you could aswell quote the scepticism that same report shows towards the 603 while you are at it. IIRC according to Rodeike the DB 603A had an MRO inteval of 40 or less by late autumn 1943. So it wasn't doing much better than the BMW was almost 2 years before.

The DB 603 was a great engine and would've been a very good choice for the higher altitude fighter version, but it would've been a mistake to design the Fw 190 for that engine from the start as it would've delayed introduction until at least mid 1943, by this time the Mustang is already nearly there. So you basically are on even terms again. Thanks to the BMW the Fw had a good year and a half of dominance. Also, instead of striving for optimum performance, they could've settled for the weaker but more trouble free Jumo 213 as early as 1942 and then wait for the DB603 to become reliable since the two were interchangeable. Which they did in the end anyways, just very late.

Sticking with the 139 would've given you a slightly better performing (e.g. ~10 km/h faster) but more difficult to fly and significantly weaker armed fighter with very little potential left. Essentially a dead end road. Any project for a bigger engine or increased armament would've resulted in half a new plane.

 

[davebender]

F-4 consume 350 l/h at combat power (30 min.) and have 400 liter so it's not as you told

How many liters of fuel do you think are available after subtracting take off, climb to altitude, transit to the combat area, return to base and landing?

 

[Vincenzo]

How many liters of fuel do you think are available after subtracting take off, climb to altitude, transit to the combat area, return to base and landing?

no long away from base a 200 liters maybe a good estime, just 175 liters for half hour at combat and 25 of reserve, or less time at combat and some minutes at take off power (when cleared)

 

[delcyros]

I am aware of the comparison test you are getting your numbers from, yes. But you should keep in mind that it stems from the earlier days of the Fw 190 and no doubt, there was still some scepticism towards the plane. Oh and you could aswell quote the scepticism that same report shows towards the 603 while you are at it. IIRC according to Rodeike the DB 603A had an MRO inteval of 40 or less by late autumn 1943. So it wasn't doing much better than the BMW was almost 2 years before.

The key aspect is that in 1941 and 1942, the Db-603A was not different in reliability than the contemporaneous BMW-801C/D versions wrt MRO times. If You can press a BMW-801C into service with 25 hours avg. lifetime, You can put a Db-603A into service with comparable servicelifetimes. We know that in 1941 Daimler Benz company delivered 215 Db-603A production engines, while in 1942 over 700 engines were delivered to be followed by close to 3000 specimen in 1943. This evidence suggests that the Fw-190 with Db-603 could be put into service sooner than 1943.
The BMW-801 is highly uneconomical, it needs more ressources and manhour for production and requires C3 grade fuels. The BMW-801D2 (unlike the Db-603) cannot be run on B4 grade fuels. In top of this, it was (by then) not very reliable and as a consequence had to be derated to improve service reliabilty. So it weights more, produces less power, requires more space (frontal area is more than twice that of the db-603), is less economic, reliable and arguably more costly.

The DB 603 was a great engine and would've been a very good choice for the higher altitude fighter version, but it would've been a mistake to design the Fw 190 for that engine from the start as it would've delayed introduction until at least mid 1943, by this time the Mustang is already nearly there. So you basically are on even terms again.

I doubt this. Dropping the BMW-801 would bring the db-603 into significantly larger than historical production figures for the 1941 and 1942 period. I suspect that the soonest Fw-190 with Db-603 would see service by mid/late 1942, appearing in greater numbers during 1943, a full year before the service advent of the P-51B. These mounts would have a performance advantage over the Bf-109F4/G2 they would come to replace. By 1944 with MW-50 injection and 2250 hp increased take off power, they would be comparable to a 1945 Ta-152C performancewise and more than a match for a P-51B/P-47C, lending Daves idea some merit.

Thanks to the BMW the Fw had a good year and a half of dominance.

That´s nothing to give the Fw-190A or the BMW-powerplant particularely special credit for. During the 1941 to late 1942 period, the Bf-109F4 had even more performance than the Fw-190A and dominated the airspaces not only over Russia, Malta and North Afrika but also over France whenever deployed. It´s not that the Fw-190 saved the Luftwaffe in this timeframe, the period versions of the Bf-109 were already establishing aerial superiority on their own.

Also, instead of striving for optimum performance, they could've settled for the weaker but more trouble free Jumo 213 as early as 1942 and then wait for the DB603 to become reliable since the two were interchangeable. Which they did in the end anyways, just very late.

No argument here.

Sticking with the 139 would've given you a slightly better performing (e.g. ~10 km/h faster) but more difficult to fly and significantly weaker armed fighter with very little potential left. Essentially a dead end road. Any project for a bigger engine or increased armament would've resulted in half a new plane.

Agreed. That´s exactly why I think Kurt Tank should have considered the Db-603/Jumo-213 in the first place. The BMW-801 was a very complicated, wasteful engine which put considerable strain on the logistic chain and eventually despite all praise for the Fw-190 worsened the german war effort by industrial diversification and increased consumption of C3 fuels. It´s a missed opportunity.
By 1942, a single BMW-801D2 required avg. 2.000 manhours and 45.000 to 65.000 Reichsmark (16.000 manhours for all secondary and tertiary efforts taken into account for).

 

[davebender]

By 1942, a single BMW-801D2 required avg. 2.000 manhours and 45.000 to 65.000 Reichsmark

price data for 1941 for some German aircraft types, via Olaf Groehlers GdLK, 1910-1980:
Without engine / with engine, in Reichsmarks (RM)
Bf 109E : 58 000 / 85 970

So a BMW801 engine cost roughly twice as much as the DB601. Does anyone have a price for the DB603 and Jumo213 engines?

 

[Colin1]

Sorry
I keep harking back to this notion of the Bf109F-4 having some 416mph maximum speed and I'm just not buying it.

The Bf109F-3 and -4 which were produced simultaneously, replaced the F-2 variant on the assembly lines in early 1942 and differed from the F-2 in that they incorporated the long-awaited DB601E as the basic powerplant. The powerplant change was the only difference between the F-2 and the F-3; however, the F-4 incorporated a number of additional modifications that were not externally discernible. These included an increase in the calibre of the MG 151 from 15mm to 20mm, the use of the new self-sealing tanks and an increase in the armour protection for the pilot.
Both the F-3 and the F-4 utilized the FuG 7a radio and Revi C/12D gunsight.

A number of F-4s were also modified like the F-2 variant with the incorporation of the GM 1 nitrous oxide boost system (Bf109F-4/Z).

So we're looking at emergency power only, here


The installation of the GM 1 boost system in the F-2 produced the Bf109F-2/Z. These models were followed by the F-3 which utilised the DB601E engine and the F-4 which was fitted with a similar powerplant but had its engine-mounted MG 151 changed from 15mm to 20mm and ammo capacity reduced 25% to 150 rounds.
The fighter-bomber version of the F-4 set out on its first duties druing the early weeks of 1942. There was little difference between the Bf109F-4/B and the standard fighter model apart from the installation of racks for either an SC 250 bomb or four SC 50 bombs.
Other modifications to the F-4 produced the tropicalised version and the GM 1-boosted Bf109F-4/Z.

Once again, emergency power rating only, this is not the same as a sustained speed advantage over the Spitfire Mk V over France and if it was, why is it not mentioned in combat reports in the same way the speed advantage of the Fw190 was? Neither source mentions an overwhelming advantage (which 416mph surely was) for the F-4 over its rivals.

Sources
Messerschmitt Bf109
Robert Grinsell
Jane's
ISBN: 0 7106 0034 8
Pages 22 - 23

The Fighting Me109
Uwe Feist
Arms Armour
ISBN: 0 85368 961 X
Pages 34 - 35

 

[johnbr]

Whar about the DB 605.

 

[delcyros]

Sorry
I keep harking back to this notion of the Bf109F-4 having some 416mph maximum speed and I'm just not buying it.


Once again, emergency power rating only, this is not the same as a sustained speed advantage over the Spitfire Mk V over France and if it was, why is it not mentioned in combat reports in the same way the speed advantage of the Fw190 was? Neither source mentions an overwhelming advantage (which 416mph surely was) for the F-4 over its rivals.

These are secondary sources. M. Rausch analysed primary ones. In top of this, both the two books aforementioned were written before the relevant primary sources were digged out in the archives, so they are written before M. Rausch made an impact in the discussion. The Bf-109F4 has a very significant speed advantage over the Spit V as soon as it was cleared for 1.42 ata take off power (5 min. clearance), which was cleared very early in 1942. The performance figures in the books refer to the downrated Db-601E which was cleared only to 1.3 ata. Top speed with 1.3 ata was in between 620 and 630 Km/h at optimum altitude, which is very comparable to the 620/630 Km/h top speed of the Bf-109G2 at 1.3 ata (30 minutes rating). With 1.42 ata (5 min. take off power -NOTE: this is not war emergancy power sustained by ADI or No2 injection! Such would have been "erhöhte Notleistung (MW-50) or Sondernotleistung (GM-1) in german terminology), the F4 (and G2, using the same 1.42 ata) was good for 650 to 670 Km/h, depending on individual differences between the machines.
There are multiple german and soviet primary sources to confirm this. Neither the UK nor the US ever tested a Bf-109F or G with 1.42 ata. All their tests refer to 1.3 ata powersetting, which would imply 30 minutes ratings. Check M. Rausch´s site for them. No Bf-109F4 was ever tested. They just claculated the speed with the increased performance of the Db-601E (1.3ata).
The german and soviet tests (with service planes, not prototypes!) do always show the Bf-109F was faster than the Fw-190A, it´s only the british evaluation, done with a lower rating in case of the F2/trop and a higher in case of the -190A, which implies the opposite. The 109G6 appears to be slower at 645 Km/h and 1.42 ata (clean fighter configuration without gunpods).
If you check the Bf-109G1 high altitude fighters with pressurized cockpit, otherwise identic to the Bf-109 F4/z You an find these values confirmed as the models were trialed with Db-601E and Db-605A (but without GM-1).
The top speed with Db-601E at sea level TAS was 514 Km/h (319 mph)
--"--- with Db-60E at FTH TAS was 622 Km/h (386 mph).
The top speed with Db-605A at sea level TAS was 507 Km/h (315 mph)
--"--- with Db-605A at FTH TAS was 628 Km/h (390 mph).

All speed trials were corrected for position error, compressibility and normal temperatures/ pressures.
The Db-601E run at 2500 rpm and 30 minutes climb take off power (1.30 ata). The Db605A run at 2600 rpm and 1.3 ata, too.
Consider that the G1 was heavier than the F4 and using military power, not max. power!
These speed graphs are in general agreement with
a soviet test of a Bf-109F4 with worn out engine and TAS = 624 Km/h with Db601E at FTH
The rating was 1.3 ata, too.
Another soviet test with a captured 109 G2, appearently cleared for 1.42 ata gave 666 Km/h at FTH.
So we are in the same ballpark.
A clean Spitfire V´s top speed was 369 to 375 m.p.h at +9 lbs boost (primary sources: W.3134; X.4922; AA.873).
The tropical Spitfire V with Vokes filter was down to 354 m.p.h top speed (primary source: AB.320), which was nearly 20 m.p.h slower than the Bf-109F2/trop and even more distant to the -109f4/trop. With Aboukir filter it would have been better but still slower than the F2 with trop conversion.
By late 1942, the boost rating of the Merlin 45 was increased to +16 lbs (3 minutes rating), which didn´t alter the SpitVc top speed (AA.878 = 369 m.p.h) but significantly improved climb and speed at lower altitudes.

At the bottom line, You have the -109F4 beeing 10-20 mph faster than the Spit V before february 1942 and 30-40 mph faster after february 1942. I consider this a decisive performance advantage. The Bf-109F4/G2 was heads and shoulder above the Spitfire V and more or less the equal of the Spitfire IX, which hit 402 mph at +15.2 lbs (at comparable 5 minute rating, see BF274)
And I am not that optimistic with regard to the Spitfire V´s fighter versus fighter exchange ratio against Bf-109F which appear to be negative over Malta, North Afrika and France in the period in question.

 

[KrazyKraut]

delcyros, i will adress your points later this week as i am pretty loaded with work atm.

 

[Vincenzo]

Sorry

The Bf109F-3 and -4 which were produced simultaneously, replaced the F-2 variant on the assembly lines in early 1942 a.

also this in wrong F-4 was operational in summer '41 like Spit V

 

[davebender]

Kurfurst is the expert on the Me-109. However I found this on Wikipedia.

Production Dates.
Me-109F1. Aug 1940 to Feb 1941. 208 total.
Me-109F2. Oct 1940 to Aug 1941. 1,380 total.
Me-109F3. Oct 1940 to Jan 1941. Only a few produced.
Me-109F4. May 1941 to May 1942. 1,841 total.
.....544 built as F4/Z with GM-1 injection.

Me-109G1. Feb - Jun 1942. 167 total.
Me-109G2. May 1942 - Feb 1943. 1,586 total.
Me-109G3. Jan - Feb 1943. 50 total.
Me-109G4. Sep 1942 to Jul 1943. 1,242 total.
Me-109G5. May 1943 to Aug 1944. 475 total.

Me-109G6. Feb 1943 to mid 1944. 12,000 total.
That's mass production!

 

[Colin1]

Me-109F4. May 1941 to May 1942. 1,841 total.
.....544 built as F4/Z with GM-1 injection

Any mention of a DB603 installation?

 

[Kurfürst]

Sorry
I keep harking back to this notion of the Bf109F-4 having some 416mph maximum speed and I'm just not buying it.

Hmm, the F-4 with the DB 601E at 1,42ata had a very similiar output to the DB 605A at 1,3ata (the maximum authorized boost for both engines in 1942). The airframes were almost completely identical as well (aerodynamics-wise).

And, there are about a dozen flight tests, reports with the 109G credited with 660 or so km/h at 1,3ata. I don't see any reason why the F-4 would be unable to reach similiar speeds at 1,42ata. Plus there is the curve with the F-4 figures from Rechlin's flight test showing 670.. this result might be without compressibility correction, as sometimes speculated, but even with compressibility correction it should be around 655 kph TAS. Pretty much in the same ballpark.

Once again, emergency power rating only, this is not the same as a sustained speed advantage over the Spitfire Mk V over France and if it was, why is it not mentioned in combat reports in the same way the speed advantage of the Fw190 was? Neither source mentions an overwhelming advantage (which 416mph surely was) for the F-4 over its rivals.

The possible reason is that 1.42ata for the F-4 appears to be cleared at the turnover of 1941/42; at 1.3ata the F-4 did around 635 kph at altitude, a significant advantage over the Spit V still, but not as depressing. OTOH during 1942 most 109s were gradually replaced by 190s in the West. There was quite simply little comparison. There were few 109s in the West, and few Spitfires in the Desert - and the two would seldom meet elsewhere.

 

[Kurfürst]

I'm interested in where you got these figures from.
I can't find satisfactory concensus over the maximum speed of the F-4; these range from 354 to 390mph. The higher figures seem to be representative of maximum emergency speed and the lower figures normal combat speed.

These figures can be traced down to British intel's estimates of the F-4's speed, based on the figures they obtained on Pingel's F-2 that crash landed in Britain. Problem is, Pingel's F-2 was already in such a poor state when they measured it, that it achieved far lower speeds than it would be capable normally - and the British estimates were based on that plane's speed figures...

See here: Kurfrst - A.F.D.U. Tactical Trials - Me.109F aircraft

Again, that seems ambitious, I can't find anything that puts the G-2 over 400mph.

The official German specification for the G-1/G-2/G-3/G-4 (sans GM-1 boost), at 1.3ata 30-min rating was 660 kph/410 mph at altitude. All produced aircraft had to satisfy this within +/- 3% tolerance in a clean state.

There is a set of some 13 production aircraft tested at Erla factory, the avarage is damn close to the official specs, without taking into account the test was done at 120mm radiator opening, instead of the standard of 50mm; correcting the figures would yield a bit higher figure. Apparently, the three Gustavs (a G-2, a G-2 with gondies, a G-4 which had fixed tailwheel) captured and tested by the Soviets satisfied the official specs almost precisely.

I can only guess the G-2's top speed should it run at 1.42ata (which was initially banned); some datasheetsI have seen suggest 685 kph, which seems rather reasonable.
With GM-1 boost, there are some rather shocking figures, but I can't disclose them yet.. suffice to say, with GM-1 the Gustav had more juice to go at altitude than even the DB 605D powered Bf 109K...

 

[tomo pauk]

...

With GM-1 boost, there are some rather shocking figures, but I can't disclose them yet..
...

Why not?

 

[Vincenzo]

Kurfurst is the expert on the Me-109. However I found this on Wikipedia.

Production Dates.
Me-109F1. Aug 1940 to Feb 1941. 208 total.
Me-109F2. Oct 1940 to Aug 1941. 1,380 total.
Me-109F3. Oct 1940 to Jan 1941. Only a few produced.
Me-109F4. May 1941 to May 1942. 1,841 total.
.....544 built as F4/Z with GM-1 injection.

Me-109G1. Feb - Jun 1942. 167 total.
Me-109G2. May 1942 - Feb 1943. 1,586 total.
Me-109G3. Jan - Feb 1943. 50 total.
Me-109G4. Sep 1942 to Jul 1943. 1,242 total.
Me-109G5. May 1943 to Aug 1944. 475 total.

Me-109G6. Feb 1943 to mid 1944. 12,000 total.
That's mass production!

this is not in contradiction with my affermation

 

[delcyros]

Hmm, the F-4 with the DB 601E at 1,42ata had a very similiar output to the DB 605A at 1,3ata (the maximum authorized boost for both engines in 1942). The airframes were almost completely identical as well (aerodynamics-wise). And, there are about a dozen flight tests, reports with the 109G credited with 660 or so km/h at 1,3ata.
The official German specification for the G-1/G-2/G-3/G-4 (sans GM-1 boost), at 1.3ata 30-min rating was 660 kph/410 mph at altitude. All produced aircraft had to satisfy this within +/- 3% tolerance in a clean state.

Dear Kurfürst,

I note that the 660 Km/h top speed fo rthe G-1/G2 is either related to 1.42 ata or in other sources to 1.3 ata. Most tests do show 1.3 ata in the region of 620 to 635 Km/h for these A/C at altitude. It´s basically only the Erla report and the Rechlin report to state 660 Km/h in relation with 1.3 ata or do I miss some? Please feel free to correct me.
The VVS test with 666 Km/h was with an unblocked engine (1475 hp aviable as opposed to 1200 hp for the Bf-109F4 they tested, pointing to 1.3 ata in the latter and 1.42 ata in the former case, explaining the 624 Km/h and 666 Km/h top speed figures well)
The difference between Db-601E and Db-605A was not that significant in terms of power at the different ata ratings (without ram taken into account for):

rating----Db-601E (@4800m)----Db-605A(@5700m)--
1.30ata---1200hp---------------1260hp---
1.42ata---1325hp---------------1355hp---

It rather appears that the Db-605 achieves a higher FTH than the Db-601E. Still, the discrepiancies in the sources with different top speed figures for the G-series Bf-109 require a good explenation. Just wondering.

 

[delcyros]

These are a comparison graph shown for all flight test data for the Bf-109G1/G2 in clean fighter configuration that I have come across. Not included are G2/trop and other tests with gunpods/bombs, etc.
A mean curve is shown, too. The Erla tests are corrected for 50mm radiator flap position.
The mean curve appears to be reasonably close to the Messerschmidt specifiction.

 

[Vincenzo]

corrected also for tailwheel, was retractable ?

 

[delcyros]

No.It´s not corrected for tailwheel. For comparison I compiled the three Spitfire IX, +15 lbs speed trials from WWII Aircraft Performance.
These are for Merlin 61 driven Spitfire and only representative for 3000rpm and clean fighter configuration.
The mean curves for both, Bf-109g1/2 and Spitfire F IX are attached below.

I suspect this is part of the bad fame, the g-series immediately got. The pilots were transferring from the -109F4, which typically at mid/late 1942 was already cleared for 1.42 ata and could sustain much better climb, top speed and turn figures than the "brand new" Bf-109G and it´s 1.30ata rating. Due to the blocking of take off emergancy power, the already heavier -G model must have been felt like a dog compared to the 1.42 ata Bf-109F4. It´s speculation, agreed, but not without raesons.

The standart Spitfire IX was faster at 30000ft. (which is essentially confirms the Air Ministry, A.I.2.(g), Whitehall
20 March 1943 report). Below ca. 28.000ft., it was either about as fast or significantly slower, depending on altitude.