Fw-190 vs Spit/P-51/P-47

[Soren]

Davparlr, I was looking at one from Army Air Forces Proving Ground Command
Eglin Field in Florida dated 7th July 1944, where tail nr. 43-24755, 43-24757 and 43-24775 were tested at 75" MP. - The engines being V-1650-7's using 44-1 fuel.

I read somewhere that the Fw-190D could generate significant more power than the P-51B which would indicate either the numbers of the P-51B (which seems solid) or the Fw-190D are suspect.

They are not suspect, the way the testing was carried out was just different. IIRC the German way of measuring Time to Climb was starting the clock already at the start of the take off roll, where'as the US and British way was to start the clock from the point of take off.

 

[davparlr]

Davparlr, I was looking at one from Army Air Forces Proving Ground Command
Eglin Field in Florida dated 7th July 1944, where tail nr. 43-24755, 43-24757 and 43-24775 were tested at 75" MP. - The engines being V-1650-7's using 44-1 fuel.

That is the same configuration as the chart I was using. Yours data seems more believable, but the chart I used certainly looks authentic.

They are not suspect, the way the testing was carried out was just different. IIRC the German way of measuring Time to Climb was starting the clock already at the start of the take off roll, where'as the US and British way was to start the clock from the point of take off.

This certainly clarifies some confusion, thanks.

 

[Hop]

It should be quite obvious to you that the engine didn't perform nearly as well as it should have Hop, and this is backed up by the report itself as well as German pilot testimonies

But at what point did the engine not perform as well as it should have? Before the test, during the test, or after the test? If it's the first, all the figures from the test are wrong. If the second, it might have been performing properly (or even better than normal) before failing, if the last it might have been performing better than normal throughout.

From reading the tests, it's clearly not the last. From looking at the climb performance figurres, its not the first either.

All we know for sure from the assesment of Faber's plane is that the RAF ran it at above the recommended power settings, and the engine didn't run properly for some of the time.

The engine's reliability was never ever questioned by the LW pilots who flew the bird, and it was described as a very nicely running engine which is backed up by a great reliability record.

As late as December 1941 the Luftwaffe was recommending that the 190 not be flown over water because of engine reliability.

bviously something went wrong in the translation of the climb rate tests performed by the RAE, cause those figures are just completely unreal, esp. when compared to the speeds achieved

Exactly. Combined with the very low FTH, I suspect there was a problem with the automatic control. The high climb rates at high altitude could only have been achieved by an increase in RPM, or by a mistake in readings.

All in all, the tests of Faber's plane, which were conducted in a hurry on a totally unknown aircraft, don't tell us that much about the real performance. If the speed was too low, and the climb rate too high, what stock can be set in the results of the evaluations?

In any case you're better off asking Crumpp about this, as I'm simply not in the mood for a long discussion regarding your assumptions on this subject.

Soren, we had a discussion some time ago about the performance of the 109K4 at 1.98 ata. Months after you had registered at Butch's forum, I'm still waiting for your response.

And about the Spit IX pilots confidence when facing the FW190, remember by 42-43 the A-4, A-5 A-6 were serving with the LW, and these gave the RAF fighters a serious beating over the channel.

No, they didn't. By 1943 the RAF very much had the upper hand.

So its of no use comparing the Spit IX with the A-3, as newer and more powerful 190's had been introduced by the time of the Spit IX's introduction.

And newer Spitfire IXs, too. The test against Faber's plane was conducted by a Spitfire F IX with Merlin 61, limited to 18 lbs boost. The Merlin 63, 66 and 70 increased the boost to 18 lbs, adding a few hundred hp, and increased the climb rate at lower levels by up to 1,000 ft/min, and speed by about 20 mph at lower levels.

uring the period of February to July 1942, the JG 2 26 shot down atleast 335 enemy a/c to the loss of just 85 FW-190 BF-109's.

Which was of course before the introduction of the Spitfire IX.

And the casualty figure looks a bit low. Caldwell lists at least 40 JG 26 pilots killed during the period. considering pilots usually die half as often as their planes, that would make JG 2 very quiet.

And on August 19th 1942, the day of the British operation "Jubilee", JG 2 26 despite being heavily outnumbered claimed 96 aerial victories while losing just 21 fighters themselves - the RAF admitted the loss of 103 a/c that day, 88 of which were Spitfires.

About 60 Spitfires lost, according to Tony Wood's lists.

As I understand it for operation Jubilee the British had 46 squadrons of spitfires, but only 4 of those had the Spit IX. The others were Mk V which we all admit was at a significant disadvantage over the Fw190.

The Spitfire IXs were only partially committed to Dieppe, the 8th AF was flying their first major bombing sortie that day, and the Spitfire IXs were tasked with escort for them.

t must be noted here that when the P-51B arrived in May of 1943 it was similar in performance to the contemporary Spitfire IX in ceiling and rate of climb

Well, climb rate was far lower on the P-51 and the ceiling was about 2,000ft lower for similar altitude versions. But more importantly, the first production P-51B flew in May 43, they didn't actually get into action until December 43.

I did not get the same P-51B performance numbers you did. From a flight test chart for Tail Number 43-24777, tested 3-31-44, at 75" Hg, 9680 lbs and wing racks (see my referenced site in previous message) I interpreted the following time to climb data.
6,561 ft 1.8 min
13,123 3.2
19,685 5.2
26,246 8.0
32,808 12.5

Bear in mind maximum power on the Merlin was developed at 67" MAP on 100/130 octane fuel. The figures for 75" required 100/150 octane fuel, which didn't enter service until the summer of 1944. Even then, in service the 8th AF only used 72", although the RAF used up to 81" in their Merlin engined aircraft (Spitfire IXs mainly, but also Mustangs, Mosquitos)

In short, look at the performance figures for the P-51B at 67" to represent P-51Bs from Dec 1943 to summer 1944, and performance figures at 72" after that.

I read somewhere that the Fw-190D could generate significant more power than the P-51B which would indicate either the numbers of the P-51B (which seems solid) or the Fw-190D are suspect.

At 67" MAP the Merlin developed about 1750 hp peak, which is considerably less than the Jumo 213 (1900ps was common, over 2000 possible in some configurations). However, at 81" the Merlin put out over 2000hp, so 75" would be somewhere around 1900hp.

I think the Spit IX would be lighter on it feet than the P-51B and is probably a better dogfighter as is the Fw-190D.

Yes. The P-51B on 67" climbed at a peak rate of 3,450 ft/min with 180 gallons of fuel. The Spitfire LF IX at 67" (18 lbs in British terminology) something around 4,700 ft/min with 102 gallons of fuel, and a much more powerfull armament.

 

[Glider]

This is digressing a little but you may be able to help me. I know that later Spit IX's had an extra 75 gallon tank internally in the rear fusulage giving a similar amount of fuel as the P51. What I don't know is what different this made to the range. Can either of you help me?

Finally just a thought re the Spit IX vs 190 debate. Don't forget the other improvement the Spit had which gave it a considerable advantage over the 190 in actual combat and that is the new advanced gunsights. This was I suggest, as least as important as as an extra 100/200 hp from the engine.

 

[Jabberwocky]

This is digressing a little but you may be able to help me. I know that later Spit IX's had an extra 75 gallon tank internally in the rear fusulage giving a similar amount of fuel as the P51. What I don't know is what different this made to the range. Can either of you help me?

Finally just a thought re the Spit IX vs 190 debate. Don't forget the other improvement the Spit had which gave it a considerable advantage over the 190 in actual combat and that is the new advanced gunsights. This was I suggest, as least as important as as an extra 100/200 hp from the engine.

It actually gave them about three fifths as much fuel as a P-51, and less range because the Mustang was a more slippery airframe and cruised a little faster at the same level of consumption. A fully loaded P-51D carried about 280 US gal and a further 150-220 US gal in drop tanks, for a total of ~420-490 US gal.

A fully loaded Spitfire IX with rear fuselage tanks carried about 150-160 Imperial gal (180-192 US gal) and a 90 Imp gal (108 US gal) drop tank, for a total of around 240-250 Imp gal (288-300 US gal) . The larger 170 gal drop tanks was usually reserved for ferry operations, not combat operations

The Spit IX came in a couple of flavours in regards to fuel tankage:

1. 85 gal internal, nose tanks (standard)

2. 95 gal internal, enlarged nose tanks (non-standard, only some small production runs and refits)

3. 85 gal nose tanks + 75 gal rear tanks (standard from mid-late 1944)

4. 95 gal nose tanks + 75 gal rear tanks (non standard)

5. 85 gal nose tanks + 65 gal rear tanks (standard from 1945 onwards)

Mk IXs and XVI with the bubbletop canopy had smaller rear fuselage tanks, usually 50-60 gal, but they were often removed due to weak directional stability caused by the reduction of vertical area (corrected somewhat by the later larger tail)

The effect on range was significant. On plain old internal tankage, the Mk IX had a (one way) range of about 460-475 miles. Adding a 45 gal drop tank adds about 50% to that and addding a 90 gal drop tank essentially doubles it.

The problem was that with just 85 gal internally, there really wasn't enough fuel to effectively use the 90 gal drop tank to stretch the range.

However, when the rear tank was added, all of a sudden the Spitfires could take off and climb on the rear tanks, cruise on the drop tank and then punch the drop tank off for combat and still have full foward tanks to fight with and go home on. The rear fuselage tanks effectively increase the standard combat radius from 225-250 miles to around 400-425 miles. Not enough for Berlin, but still enough to cover the Ruhr and some of Western Germany from bases in the UK, a marked improvement.

 

[Gnomey]

Yep, they did increase the range (as can be seen from this table comparing the MK-I to the Seafire 46 (last production version))

Supermarine Spitfire - Technical Data

 

[davparlr]

Well, climb rate was far lower on the P-51 and the ceiling was about 2,000ft lower for similar altitude versions. But more importantly, the first production P-51B flew in May 43, they didn't actually get into action until December 43.

What would have been the equivalent Spitfire in December 1943? Spitfire configurations always confuse me. What would the equivalent Spitfire version with the Packard Merlin-3 and -7? Some of the data I have seen indicated a P-51B with a -3 engine had a similar ceiling as the Spit IX, 42,000 ft. although I am confused about the equivalency.

Bear in mind maximum power on the Merlin was developed at 67" MAP on 100/130 octane fuel. The figures for 75" required 100/150 octane fuel, which didn't enter service until the summer of 1944. Even then, in service the 8th AF only used 72", although the RAF used up to 81" in their Merlin engined aircraft (Spitfire IXs mainly, but also Mustangs, Mosquitos)

In short, look at the performance figures for the P-51B at 67" to represent P-51Bs from Dec 1943 to summer 1944, and performance figures at 72" after that.

At 67" MAP the Merlin developed about 1750 hp peak, which is considerably less than the Jumo 213 (1900ps was common, over 2000 possible in some configurations). However, at 81" the Merlin put out over 2000hp, so 75" would be somewhere around 1900hp.

Good info, thanks

Yes, the P-51B on 67" climbed at a peak rate of 3,450 ft/min with 180 gallons of fuel. The Spitfire LF IX at 67" (18 lbs in British terminology) something around 4,700 ft/min with 102 gallons of fuel, and a much more powerfull armament.

With your info on fuel, this appears correct. The P-51B did seem to have a substantial top speed advantage of about 10% (30-40mph) over the envelope. Even compared to later IX models although not as much (about 20mph)

 

[Hop]

What would have been the equivalent Spitfire in December 1943?

In December 1943 there were 3 Spitfire IX variants. The LF IX (most common), the F IX and the HF IX (least common).

LF stands for Low Fighter, F for Fighter, HF for High Fighter.

They were fitted with the Merlin 66, 63 and 70 respectively.

The only real differences between them were in best altitudes. The LF IX had a peak speed developed about 21,000ft. The F IX about 25,000 ft, the HF IX 27,500ft.

Speeds were about 404 mph for the LF IX, 408 for the F IX, 416 for the HF IX.

Spitfire configurations always confuse me. What would the equivalent Spitfire version with the Packard Merlin-3 and -7?

They're not exactly the same, but the -3 was somewhere between Merlin 63 in the F IX and the Merlin 70 in the HF IX, and the -7 was similar to the Merlin 66 in the LF IX.

Bear in mind there was an earlier F IX, from July 1942 with the Merlin 61, which wasn't as powerfull. The Merlin 63 began to take over early in 1943, and the Merlin 61 seems to have been removed from service Spitfires quite quickly.

Some of the data I have seen indicated a P-51B with a -3 engine had a similar ceiling as the Spit IX, 42,000 ft.

Official service ceiling for the F IX with Merlin 63 was 44,000ft, and 45,000 ft for the HF IX.

The Spit IX came in a couple of flavours in regards to fuel tankage:

1. 85 gal internal, nose tanks (standard)

2. 95 gal internal, enlarged nose tanks (non-standard, only some small production runs and refits)

3. 85 gal nose tanks + 75 gal rear tanks (standard from mid-late 1944)

4. 95 gal nose tanks + 75 gal rear tanks (non standard)

5. 85 gal nose tanks + 65 gal rear tanks (standard from 1945 onwards)

The 95 gallon forward tanks became standard later on in Spitfire IX production, I believe.

Later Spitfire IXs were also fitted with 2 18 gallon bag tanks in the wing leading edge.

A better comparison for range in the Spitfire is with the Spitfire VIII, which was fitted with extra tankage as standard for operations overseas. Spitfire VIIIs had 96 gallons in forward tanks and 27 gallons in the wings, for a total normal internal fuel load of 123 imp gallons.

The Spitfire VIII was similar to the Spitfire IX, just a slightly revised airframe. Performance was similar.

There's an Australian test of fuel consumption in the Spitfire VIII at 20,000ft:

The effect on range was significant. On plain old internal tankage, the Mk IX had a (one way) range of about 460-475 miles.

That figure is for the early Merlin 61 engined aircraft. The Merlin 63, 66 and 70 were different engines, with different carbs. The only test I know of with the later engines is the one I linked above.

 

[davparlr]

Thanks. Great info on the Spitfire and the Merlin. The Merlin was certainly a wonderful engine. Both the Allies and Axis had great engines to power their airborne war machines.

 

[Soren]

Hop,

The engine ran improperly long before the testing had begun, as the sparkplugs all suffered from fouling (Later discovered by replacing them with Siemens sparkplugs taken from the BMW 801A engine of a crashed Do 217 bomber), and that allied fuel was used didn't help matters either.

And as I said, something went wrong translating the climb rate of the a/c, it simply didn't climb that well at that setting.

And I hope that when you come to your senses you will realize that the engine certainly at no point ran better than it should, cause that is just a downright silly idea.

Also Faber's A-3 was never run at above recommended settings, and I have no idea what makes you think otherwise. As written in the report itself: "There are indications that the engine of this aircraft is de-rated, this being supported by the pilot's instruction card found in the cockpit."

At no point did the power setting ever exceed 1.42ata in the British tests with the a/c.

As late as December 1941 the Luftwaffe was recommending that the 190 not be flown over water because of engine reliability.

Firstly I'm going to need a source on that, secondly the A-3 with its BMW-801D engine hadn't even entered production by then.

The BMW-801D engine was an extremely powerful, reliable and nicely running engine with an astonishing service record, and I repeat; never was its reliability ever questioned by the men who flew or maintained the bird.

As Eric Brown put it himself:
"it purred smoothly as it ran."

No, they didn't. By 1943 the RAF very much had the upper hand.

You must be kidding me ! In terms of Kill/loss ratio the LW were giving the RAF a licking during that period !

And the casualty figure looks a bit low. Caldwell lists at least 40 JG 26 pilots killed during the period. considering pilots usually die half as often as their planes, that would make JG 2 very quiet.

According to German loss records 85 a/c were lost in that period by JG 2 26, and where you got your "Pilots usually die half of the time" theory I have no idea.

About 60 Spitfires lost, according to Tony Wood's lists.

Tony Wood ? Yes ofcourse

I think I'm going to stick with Caldwell on this one though..

 

[Hop]

And I hope that when you come to your senses you will realize that the engine certainly at no point ran better than it should, cause that is just a downright silly idea.

It's perfectly possible to get more power out of an engine, by overboosting or over revving it. Neither does it much good, of course...

Also Faber's A-3 was never run at above recommended settings, and I have no idea what makes you think otherwise.

The fact that it says so in black and white in the RAE report.

s written in the report itself: "There are indications that the engine of this aircraft is de-rated, this being supported by the pilot's instruction card found in the cockpit."

Yes. It also says:

The following table, taken from the cockpit, gives the operational limitations of the engine on this aircraft:

Conditions Time Boost    RPM
                       ATA   Up to 6km Over 6km
Take off   3 min  1.35    2450        2450
and level  

Climbing  30 min  1.28    2350        2450

Continuous         1.14   2250         2450

Those were the ratings on Faber's plane.

From the AFDU report:

Speed runs (maximum 3 minutes ratings used)

FW 190 2700 rpm @ 1.42 ata

In the case of the FW 190 the 30 minute rating was taken to be 2450 rpm @ 1/35 ata

So, the Germans had rated Faber's 190 at 1.35 @ 2450 rpm for 3 mins, the British ran it at 2700 rpm @ 1.42 ata for 3 mins.

The Germans had rated Faber's 190 at 2350 rpm @ 1.28 ata for 30 mins, the British ran it at 2450 rpm @ 1.35 ata for 30 mins.

At no point did the power setting ever exceed 1.42ata in the British tests with the a/c.

Not that we know of. But Faber's plane was rated at a max of 1.35 ata and 2450 rpm, not the 1.42 ata and 2700 rpm the British ran it at.

Firstly I'm going to need a source on that,

I believe it's from the December 1941 evaluation of the Fw 190 and Bf 109, either by Reichlin or one of the channel JGs.

The BMW-801D engine was an extremely powerful, reliable and nicely running engine with an astonishing service record, and I repeat; never was its reliability ever questioned by the men who flew or maintained the bird.

"Unreliability would be the curse of the BMW 801 for its entire existence"
Don Caldwell, JG 26 War Diary

According to German loss records 85 a/c were lost in that period by JG 2 26, and where you got your "Pilots usually die half of the time" theory I have no idea.

Oh, it's a fairly common rule. Some pilots bail out, you see. On the other hand, if the pilot is killed, the plane rarely survives.

It would be incredibly unusual for plane losses to equal pilot losses, and when they do it's usually due to cherry picking statistics, or incomplete statistics. Air forces usually have better records of the fate of their pilots than planes, for example.

About 60 Spitfires lost, according to Tony Wood's lists.

Tony Wood ? Yes ofcourse

I think I'm going to stick with Caldwell on this one though..

Stick with Caldwell. Caldwell doesn't say 88 Spitfires lost. He says 88 FIGHTERS lost. The RAF also used large numbers of Hurricanes at Dieppe.

 

[Glider]

Not to mention Typhoons at Dieppe. The Hurricanes were for use in GA rope and as we all know that is a dangerous game. 60 Spits out of 88 fighters lost does sound like a decent breakdown of likely losses remembering that only 4 squadrons of Spits were mk IX's.

As the Mk IX came into service its my belief and understanding that the tide turned and the Germans were losing the initiative. Sorren, have you breakdowns on the losses?

Jabber, thanks for the info on the Spitfires range and fuel load. I had the wrong idea about the P51 and had a figure of 180 as its internal fuel capacity. Thaks for putting me on the right path.

 

[Soren]

Oh for Christ's sake Hop, you contradict yourself time and again...

The British ran the engine at maximum power for only 2min at a time, and the BMW-801D would normally easily achieve this. But this is irrelevant cause the British ran Faber's A-3 at 2,450rpm @ 1.35ata during the partial climbing tests.

The official operational limitations of the BMW-801D engine:
Start u. Notleistung (3min): 1.42ata
Steig u. Kampfleistung (30min): 1.32ata
Höchstdauerleistung: 1.20 ata

Now looking at this why should the limitations for the engine on Faber's A-3 be any different from this if it wasn't because of the fact that it underperformed quite significantly ??

As to the reliability of the BMW-801 engine, you're totally forgetting the inviroments and conditions in which it had to operate, cause considering this it did much better than what could be expected !

By Crumpp:
"Certainly the 801 had teething problems as all new designs experience. These early teething problems were quickly overcome and the engine was constantly improved during its lifespan. If you factor in the fact that BMW`s reliability goal was 120 hours before being declared fully operational compared to the USAAF standard of 50 hours, there is little to compare. The Germans simply did not have the resources to get so little time out of their engines.

Using the USAAF ruler, the BMW801C was an operationally reliable motor in August on 1941. Under BMW standards it never became a reliable motor. The BMW801D2 became a reliable motor under BMW standards in June 1942. "

Also by Crumpp:
"EB-104 was also done at combat weight. Focke Wulf generally corrects their curves to Take-Off weight.

The RAE "Brief Handling Notes of FW-190A3" WNr. 313 climb measurements were calculated off data collected in partial climbs:

And corrected to a nonsensical weight (for the type) between a Type I and a Type II Jagd-einsatz. WNr. 313 was a Type II with full wing armament. The aircraft was weighed to it's actual weight and was slightly short of fuel and ammunition. It was exactly 87Kg lighter than the Focke Wulf ladeplan FW-190A3 for a Type II.

Due to the rough running of the engine, the climbs at aircrafts "Steig u Kampfleistung" rating were calculated off of one data point. The other partial climbs were done at 1.28ata or the "Dauerleistung" rating.

Quote: It's certainly arguable the 190 wasn't making proper power in the test,

There is little to argue about as it is a documented fact. More than one test of WNr. 313 had to be abandoned due to engine trouble. "

 

[Hop]

Oh for Christ's sake Hop, you contradict yourself time and again...

No Soren, I am presenting a very simple and logically consistent case.

Faber's plane was derated.

Faber's plane was tested first by the AFDU at higher than permitted settings.

Faber's plane ran roughly throughout the AFDU test, but towards the end of the test must have got worse, as the tests were abandoned.

Faber's plane was tested by the RAE at the correct settings.

Just because the engine was running roughly at the AFDU doesn't mean it wasn't producing normal power. It might have been producing more, as it was being overboosted.

The British ran the engine at maximum power for only 2min at a time, and the BMW-801D would normally easily achieve this. But this is irrelevant cause the British ran Faber's A-3 at 2,450rpm @ 1.35ata during the partial climbing tests.

It's relevant because Faber's aircraft was derated, and not allowed to use 1.42 ata. It was only allowed to use 1.35 ata for 3 minutes. The British used 1.35 ata for up to 30 minutes. They used 1.42 ata 2700 rpm, which Faber's aircraft was not allowed to use at all.

The British exceeded both the rev limit and the boost limit of Faber's aircraft.

The official operational limitations of the BMW-801D engine:
Start u. Notleistung (3min): 1.42ata
Steig u. Kampfleistung (30min): 1.32ata
Höchstdauerleistung: 1.20 ata

THE BMW 801D engine? You mean they only made one?

Of course not. That's AN engine rating. It's not the rating of the engine in Faber's aircraft. The rating of the engine in Faber's aircraft was given on the datacard in the cockpit, and was:

Start u. Notleistung (3min): 1.35ata
Steig u. Kampfleistung (30min): 1.28ata
Höchstdauerleistung: 1.14 ata

Why there is a difference between the two engines is a valid question, but the ratings of Faber's plane were explicitly stated by the RAE. 1.35 ata, 2450 rpm for 3 minutes.

As to why there is a difference, de rating of German aircraft engines was not uncommon, the 109G for example was originally supposed to use 1.42 ata, but was restricted to 1.32 (or 1.35, can't remember which) until late 1943.

Some people claim all the 190A3s were derated, some that only a proportion were, some that there was no blanket derating at all. But Faber's plane was derated, and the British ignored that and ran it at higher power settings.

Now looking at this why should the limitations for the engine on Faber's A-3 be any different from this if it wasn't because of the fact that it underperformed quite significantly ?

As I said, you'll find different explanations depending on who you ask. But it doesn't really matter, as the question is Faber's aircraft, and there is no doubt that was derated.

As to derating an engine that's performing badly, you derate an engine if it can't perform safely at the higher setting. If it was performing at less than spec when running at the lower rating, it would have been rejected. It certainly wouldn't have had a different cockpit card made up.

Quote: It's certainly arguable the 190 wasn't making proper power in the test,

There is little to argue about as it is a documented fact. More than one test of WNr. 313 had to be abandoned due to engine trouble.

One statement doesn't follow another. I could turn the turbo up on my car and get more power. How long it would reliably run is another question. But if I did so, and later suffered engine trouble, I could not safely conclude it didn't for a time produce more power than originally designed.

Quite simply, there are too many inconsistencies in the tests of Faber's plane to draw any reliable conclusions.

 

[plan_D]

As late as December 1941 the Luftwaffe was recommending that the 190 not be flown over water because of engine reliability.

I have also heard this. The BMW 801C equipped Fw 190A-1 had over-heating troubles and the fuel control system showed signs of serious trouble. The Fw 190A-2 still suffered over-heating, even with the improved BMW 801C-2 engine. The fires caused inflight led the Luftwaffe to order pilots not to fly beyond gliding distance of the coast.

The Fw 190A-3 solved most of the problems with the introduction of the BMW 801D-2 engine. The Luftwaffe lifted the ban on sea flight during early 1942.

 

[Soren]

Ok, I'm back, had a rather long week at work.

Plan_D,

That is correct, however as explained even the BMW-801C engine became reliable by USAAF standards in August 1941 - So Hop's argument that the BMW-801 engine was an unreliable engine is totally without basis.

Hop,

I disagree with you, but I simply don't have enough time to go and waste any on a long discussion with you on this subject, cause in my opinion you're making allot of ill founded assumptions. I have therefore decided to notify Crumpp about this discussion, then he can pick up this discussion from where I left off, and possibly try correcting us "experts".

But until then here's some answers by Crumpp to some questions and opinions regarding the BMW-801 engine:

quote:
Does this mean that with C3 injection cooling the BMW801D-2 could be run at full power until fuel ran out? Was the cooling effect that good?

The BMW801 tested ran at a constant cylinder temperature of 175 degrees for 4 hours with C3-Einspritzung during endurance testing. You have to understand though, that two seperate systems both using C3 as the antiknock agent were used. The Jabo-einsatz could use their system "as long as the emergency lasts". The Jagers were limited to 10 minutes but did not use as much of their onboard fuel. Each system had different injection rates.


quote:
although German engine design efforts were crippled by their level of industrial metallurgy, as for example, in the case of the later BMW 801TS/TH/F series with the turbo supercharger, a device which had serious reliability problems due to the metal in the exhaust driven turbocharger not being able to withstand the heat and rpm's required for designed operation


Please pick up a copy of the Wright Aeroengine companies metallurgical analysis of the BMW801. The German metallurgical sciences were behind in a few areas, on par with allies in some, and about 7 years ahead of them in most. The engine block of the BMW 801 is constructed of an alloy called "elektron". Look it up. Again you are confusing shortages of strategic materials with technology.

 

[Crumpp]

Hi Everyone,

Soren requested I join this thread.

Faber's plane was tested first by the AFDU at higher than permitted settings.

Do you have documentation showing this blanket de-rating of the BMW801? I certainly do not. However I have a numerous Beanstandungen's which show both JG2 and JG26 operating "de-rated" motors right alongside "normal" motors in June 1942. This makes sense as neither BMW or Focke Wulf list any other settings beside the "normal" ratings.

De-rating is tool to manage engines serviceability. All air forces operate "de-rated" motors. The most common reason for "de-rating" an engine is to burn stocks of inferior grade aviation fuel. All engines are "de-rated" for a period of time when they are brand new. It is called the break in period. BMW801's were de-rated for their first 10 hours of operation. The "de-rating" consists of pre-threaded holes in the throttle mount in which a screw is placed limiting the advance of the throttle. To return the engine to "normal" you remove the screw.

Here is an excerpt from an upcoming magazine article I am writing:

Like all new designs there were problems to be solved. When it first appeared the motor was extremely unreliable. It's life expectancy was measured in a few short hours. On 01 August 1941 Oblt. Otto Behren's Operational Test Squadron, Erprobungsstaffel 190, moved from Rechlin to Le Bourget outside of Paris to begin training the II Gruppe Jadgeschwader 26 on the FW-190A1. Although many minor technical difficulties would be solved over the next few weeks it would not be until the 06 November 1941 that III Gruppes Technical Officer, Rolf Schröder would make the biggest leap forward in reliability for the engine. At BMW's repair shop in Albert during the investigation into engine failures Schröder noticed that a simple exhaust reroute would prevent the back bottom two cylinders from overheating. The design change was immediately implemented and the aircraft modified both at the Geschwader and the Factory. Within a short period of time, the 8th Stafflekaptain, Oblt. Karl Borris received a gold watch from BMW for having the first engine to reach 100 hours of operational flight time. Borris's luck would continue to hold as he later survived a fall from 22,000 feet with a collapsed canopy suffering numerous broken bones. Average reliability would now be measured in triple figures for the BMW 801C2 series motor.

Motors that were modified were not restricted to overland flights.

This exactly what the FW190A1 Flugzeug-Handbuch instructs for the overhaul instructions for the BMW801C2 motor:

Laut TAGL Nr. 257-42 ist für die zelle die kontrollreihe 200-5 vorgesehen. Das bedeutet, daß nach 200 betreibsstunden eine Teilüberholung und nach 5 teilüberholungsabschnitten eine Grundüberholung durchgeführt werden muß. Für den Motor BMW 801 liegt eine kontrollreihe von 100-1 vor eines jahres keine teilüberholung bei einem flugzeug oder motro vorgenommen, so sind nach einer sonderprüfung die zulassungen zu verlängern. Nach 200 starts muß eine fahrwerkskontrolle eingelegt werd.

Teilüberholung instuctions can be found in the BMW Flugmotoren BMW801 MA, ML, C, u. D Handbuch und Teilüberholungsanleitung.

All new designs experience some teething troubles. I fear if WWII had started in 1937, the R-2800 would have the reputation as being very unreliable alongside the BMW801!

Just prior to World War II, engineers at both Pratt Whitney and Curtiss-Wright worked feverishly to produce the first air-cooled engine capable of more than 2,000 horsepower. The efforts of both teams were nearly thwarted by severe vibration from unexpected sources. This is the story of how the Pratt Whitney team, through hard labor and persistence, identified and solved the problems with vibration. The result was one of the most successful engines of all times - the R-2800.

http://www.enginehistory.org/NoShortDays/Development of the R-2800 Crankshaft.pdf

I loathe getting into a performance comparison discussion. They are in fact very silly undertakings given the facts of the science behind aircraft. All aircraft performance comes from the manufacturer not as absolute performance but rather as a mean average over a guaranteed performance range. Additionally atmosphere was not standard during WWII and testing procedures certainly were not either.

In the case of WNr. 313, the performance as tested by the RAE appears to be pessimistic but not outside the realm of possibility. The climb testing was calculated off four datum points gather from partial "saw" climbs at 3500 feet and 17,000 feet. Rough running of the motor was experienced throughout the test and caused one datum point to be completely disregarded by the engineers. The Tactical Trials of WNr. 313 as tested several days later were cut short due to the rough running of the engine. The RAE then removed the motor and bench tested it to determine mixture settings and timing information. Mixture/Timing adjustments and spark plug change allowed that particular motor to run smoothly on the bench. It was never flight tested and in June 1942 the alkane ratio of C3 fuel was adjusted. This prompted new plugs for the motor and a change in the mixture and timing regulations.

Here is Focke Wulf tolerances:

Here is an RAF memo explaining aircraft performance variation:

Here is the order I would rate these fighters:

#1 FW190 if I was Luftwaffe pilot who flew the FW190.

#1 Spitfire if I was an RAF pilot who flew the Spitfire.

#1 P51 if I was a USAAF pilot who flew the P51.

All the best,

Crumpp

 

[DerAdlerIstGelandet]

Good interesting info there, cool.

 

[Glider]

Hi Everyone,


Here is the order I would rate these fighters:

#1 FW190 if I was Luftwaffe pilot who flew the FW190.

#1 Spitfire if I was an RAF pilot who flew the Spitfire.

#1 P51 if I was a USAAF pilot who flew the P51.

All the best,

Crumpp

Best bit of common sense I have seen on this thread for a long time. Well said

 

[Soren]

Excellent info Crumpp