The Fw 190 A was outclassed even at low and medium altitudes?

[Jenisch]

Hello folks, it's a pleasure to join this forum!

I'm a huge fan of the 190 Anton, but I'm finding a conflict with it's performance at low and medium altitude against the Allied fighters from 1943 onwards. Against the Western Allies, particulary against the P-51, I found it to be considerably outclassed in speed. Not to say in high altitude. Some Soviets fighters in theory were also superior, specially the La-5FN and La-7. But from the German pilot's point of view, I only see complains when the fight was at high altitude, and only against the Western Allies. An American test report of a captured Anton I read is analogous to the view from German pilots.

Can someone let the things clear to me?

Thanks since now for the attention,

Marcelo Jenisch

 

[davebender]

During 1943 the Allies still had thousands of older type aircraft in service such as the P-40, Hurricane and Spitfire Mk V. The newly introduced P-47B and P-47C were nothing to brag about. Early model Fw-190As compare well to all of those aircraft.

The P-51 starts showing up during early 1944, the same time the improved Fw-190A8 entered service. The P-51D arrived in Europe during the summer of 1944, just a few months before the Fw-190D9 entered service.

 

[davparlr]

The Fw-190A was pretty well outclassed by the P-51B in speed and climb from 5k to ceiling. But the P-51B did not appear until Dec, 1943, the Fw-190A was in the war a bit over a year before.

 

[jim]

In short yes, Fw 190A was clearly behind competition in 1944
In 42 had 1700 hp , single stage supercharger, dominated the skies
In 43 had 1700 hp , single stage supercharger , had parity with alleid fighters
In 44 still had 1700 hp ( 1950 hp with boost low altitute after summer),single stage supercharger, had taken weight. In west was outperformed at low altitude by the Tempest, and medium and high altitude altitude by almost all alleid fighters. In East, in theory , was behind La7 and Yak 3 at low altitude .
Still possesed good manouverability. Reading carefully Jg 26 war diary someone can notice this gradually fall of the aircraft. As the war progressed tactiics and manouvers, both offensive and defescive, that had been proven in combat eventually lost their effectiveness as the pilots discovered (often paying with their lifes) .
Anton never recieved a GOOD, reliable engine with good power to weight ratio, never a two stafe supercharger, recieved too late wide blade propellers, had its main wheels cover removed in later models, bulges appeared all over it, weight increased as the same airframe was required to perform many diferent roles . A good pilot could defend himself using its handling, but at low altitude.only.

 

[davebender]

How many Tempest aircraft were deployed outside the British Isles prior to 1945? I suspect not many.

Typhoon vs Fw-190A8 at low altitude would be a more likely scenerio during 1944.

 

[Erich]

you guys can argue the points but LW pilots flying A-8's thought otherwise only outclassed as you guys state ............ at the higher altitudes with the P-51D.

 

[Jabberwocky]

How many Tempest aircraft were deployed outside the British Isles prior to 1945? I suspect not many.

As Allied armies advanced on the ground and the V1 threat recceded, the Manston and Newchurch Tempest wings deployed to the Continent (specifically Belgium) in September 1944. They were joined by additional squadrons transferring from Typhoons in December 1944 and January 1945.

I dont think there were ever more than about 8-10 Tempest V squadrons on the Continent at any one time.

Typhoon vs Fw-190A8 at low altitude would be a more likely scenario during 1944.

Agreed.

Over the last half of 1944, there were usually 15-18 Typhoon squadrons operating from Continental bases. Prior to 1945, there would be a maximum of five to six Tempest V squadrons operating from Continental bases.

As to low level speed vs the 190, its abit swings and round-abouts. Most of the Typhoons of the 2TAF were either bomb or rocket carriers. The bomb shackles stripped off about 5-10 mph at low altitudes. The rocket rails cost about 12-18 mph.

Balanced against this is the fact that the Typhoon of mid/late 1944 is a generally faster beast from 6-12 months earlier.

The main difference was in the switch to more powerful Sabre IIa/b engines with higher boost ratings and the fitting of the new 4 bladed prop. But there were lots and lots of detail improvements. The new cannon and wheel fairings, new tail wheel doors, new whip type aerial, revised sliding hood et al added about 20-30 mph in speed to early 1944 production aircraft compared to the 1943 production aircraft.

Lots of these improvements were also retrofit to older production aircraft. Engine swaps for the notoriously complex and unreliable Sabre were common, as most pilots felt that the newer Sabres were more reliable.

 

[vanir]

Alfred Price I believe, says the Typhoon was about to be cancelled when the "Focke Wulf threat" was revealed not only in interceptions over France but also fast low altitude jabo raids on England, so the Typhoon was ordered into production to equip two coastal squadrons for Focke Wulf interception.

It's the way he puts it anyway. Makes the Typhoon family and Fw-190 family virtually analoguous the same way as the Spit and 109 I reckon.

 

[Siegfried]

I think you need to consider that
1 P-51D opperations didn't start till December 43/January 44.
2 Despite just about every book or web web stating that the FW 190's BMW 801D2 used MW50 boost it only did so in the final FW 190A9 version of late 1944 and that had a BMW 801TS engine (also known as an E I believe) with the so called ribbentrop MW50 system retrofitted.

The aircraft did use Overboost but did so by rich mixture injection of C3 fuel.
MW50 had tended to split the cylinder heads though some A5's appatently used it
in hit and run raids.


Overboost seems to have grown from
1.35 ata
1.42 ata
1.55 ata
1.68 ata

The final FW 190A10 should have had the 801F of 2600hp, the engine was delayed by tooling/production issues.

So really one needs to compare variant with variant in the proper chronology and time period. No doubt the P-51 was fast down low.

 

[model299]

In his book, "Pursue and Destroy" the late Leonard "Kit" Carson described a chance he had to fly one. Not sure of the model, I'll get the book out tonight when I get home and look, but he liked the plane. Called it "Every inch the fighter."

 

[GregP]

The Fw 190A was reasonably fast, not the fastest, well armed (probably better than most adversaries), was not completely debugged, and was not as manueverable in pitch as the Allied opposition. It rolled much better than most Allied opposition, so it could avoid or attack in roll as well as the Allied fighters coluld in pitch. It was NOT a high altitude ighters and was at a serious disadvantage at anything over 20,000 feet.

I cannot emphasize enough that its rolling maneuverability was in direct contrast to pitch. The stall was almost without warning and it could NOT be "horsed around" without the distinct possibility of a stall / spin.

On the other hand, it is tough to pitch with your adversary if you are not in the same plane of flight, so the Fw 190 could roll away from an Allied fightger and pitch less severely, and the Allied fighter could probably out-turn the 190 but could not do so because it could not match the rolling manuever the German pilot used to attack or evade.

Basically a standoff, which favored the Allies since we were ramping up daylight bombing and aircraft production at the time.

A bit later, the Allied Spitfires in the "LF" versions could almost match the Fw 190's rolling ability, and things got more even and tipped to the LF's favor, especially in the Griffon versions with more cannons.

I love the Fw 190 and wonder why the Germans never changed the airfoil to increase the lift coefficient of the wing or the chord of the stabilator and elevator. Everything else was almost perfect! The speed has been overstaed repeatedly, but the Fw 190 was superb. Of course, so was the competition as time went on ... In the end, the Fw 190D-9 was very good, but the opposition was no longer much less good. Parity was the order of the day, or very close to it ... one way or the other.

Since the Allies had more planes, the Nazis were doomed by numbers.

There is nothing wrong with the Fw 190 in ANY model (except for engine woes in some), but there is also nothing wrong with the opposition that was generated as a result of the appearance of the Fw 190. The opponents developed after the Fw 190 came on the scene were very capable, whether from Great Britain or the U.S.A. .

I think parity moved back and forth in the war, and eventually the greater number of Allied aircraft made the difference in the air ... on the western side of things. We probably won the war due to Hitler attacking the Soviet Union in the East. If not for that, he might have won outright. The Me 109 / Fw 190 may well have been a bit superior (a separate argument, probably never to be resolved to everyone's satisfaction), but they were overwhelmed by numbers and lack of pilots, fuel, and propellers. In the end, the Nazis could not field opposition sufficient to ward off 1,000+ P-51's attacking the Reich at one time with the B-17's/B-24's/Lancasters/Hallifaxes along for effect.

The Me 163 / Me 262 were great and innovative, but not overly effective. The Natters were completely ineffective. Though wonderful performers, the Ta 152's did almost nothing due to very few being operational at any one time. They made anywhere from 67 to 200 or so Ta-152's, but no more than 67 were operational at a squadron level, and never more than about 20 at one time. How much effect can 20 airplanes HAVE when they are opposed by 1,000 Allied fighters and their bomber friends on a daily basis?

If things had dragged on, the American P-80 and the British Meteors Vampires could have made serious opposition to the Me 262 / Me 163. They actually deployed four P-80's to Italy, but never encountered Me 262s or Me-163s ... so no jet combat there.

In the end, numbers won the war. Production was VERY important, and the U.S.A. was never bombed by anybody, so we were able to contribute a lot to the arsenal, just when it was most needed. It is probably as much luck as anything that the U-boat wolfpacks were being decimated just when we needed to get supplies to Europe. In any case, the Nazis were doomed much earlier than they thought, and innocent people in Europe paid a heavy price.

 

[Siegfried]

The Fw 190A was reasonably fast, not the fastest, well armed (probably better than most adversaries), was not completely debugged, and was not as manueverable in pitch as the Allied opposition. It rolled much better than most Allied opposition, so it could avoid or attack in roll as well as the Allied fighters coluld in pitch. It was NOT a high altitude ighters and was at a serious disadvantage at anything over 20,000 feet.

I.

I think by pitch you mean climb. Its abillity to change direction was extremely good: it was instantaneous manouverabillity rather than sustained as I read it. So it could pitch up very rapidly, it just wouldn't turn into a sustained climb. It was known for manouverabillity in the vertical plane: split S and that type of thing, as well as roll rate.

As far as the wing section goes: it was one of the NACA 5 digit series: hard to improve on in the lift area. Basically Eastman Jacobs at the NACA developed the famous 4 digit series (NACA 2013 for the spitfire wing root and NACA 2007.4 or so at the outer aileron hinge) by systematic wind tunnel evaluation. Later he improved them by systematic variation of the leading edges and that is the 5 digit series. It's not actually suprising that the Germans used this outstanding work: they were inspired by the German Goetingen airfoils. Anyway, the 5 digit series could produce more lift and less drag but the side effect was a sharper stall characteristic. All the US navy fighters used NACA 5 digit.

The FW 190's harsh stall is a bit exaggerated: some allied tests on captured FW 190s talk of aileron flutter making the pilot unconscious. A fluttering aileron is not normal on a 190 and signe of bad adjustment of the complicated pushrod linkages. (latter modified). Obviously its going to stall your tips earlier (stalls start at the rear of a wing) and the shaking will disguise your warning.

The real cause of the sharp stall was the two spar wing. The two spars made the wing torsionally stiff and unlikely to be twisted in the opposit direction to the aileron and thereby reduce the roll rate (a big problem for the spitfire with its thin single spar wing). However under heavy G the tip could twist up more than the trailing edge and thereby reduce the 2 degree washout angle. There was a FW report on this. Ta 152 had a new structure, materials and more washout due to its span, apparently remained controllable in the stall.

Check out the P-80A performance tests on the Mike Williams site ww2 performance testing. I was suprised that the P-80A was noticeably slower than the Me 262 in 1946 tests except at very high altitudes where the Jumos didn't perform well. No match for a P-80C of a few years latter. Of course the allies weren't really trying after Japan surrendered.

The BMW 801 had its supercharger fluid dynamics improved, I think around late 43 and they also tinkered with the two super charger gear ratios for different versions. It could give reasonable performance to 25,000ft. Clearly not the same as a turbo though.

 

[davparlr]

The Fw 190A was reasonably fast, not the fastest, ..... and innocent people in Europe paid a heavy price.

Excellent writeup.

 

[vanir]

I think you need to consider that
1 P-51D opperations didn't start till December 43/January 44.
2 Despite just about every book or web web stating that the FW 190's BMW 801D2 used MW50 boost it only did so in the final FW 190A9 version of late 1944 and that had a BMW 801TS engine (also known as an E I believe) with the so called ribbentrop MW50 system retrofitted.

The aircraft did use Overboost but did so by rich mixture injection of C3 fuel.
MW50 had tended to split the cylinder heads though some A5's appatently used it
in hit and run raids.


Overboost seems to have grown from
1.35 ata
1.42 ata
1.55 ata
1.68 ata

The final FW 190A10 should have had the 801F of 2600hp, the engine was delayed by tooling/production issues.

So really one needs to compare variant with variant in the proper chronology and time period. No doubt the P-51 was fast down low.

Nice post, it always bugs me the way the distinction between the two overboost systems used is often reported incorrectly.
The 801S was the engine name on the A-9/F-9 which used components from the 801F prototype development installed in the regular 801D2, when you mounted it with all anciliaries and put the armoured frame around it with the oil cooler, ready to be bolted to the blank front of a fuselage, the "power egg" complete and assembled is called the 801TS.
It was supposed to get the 801F but it wasn't ready and then was cancelled. There was no intention to produce a 190A-10, the RLM states by Dec44 it was going to halt/transition Anton production in 45 in favour of the long noses and jet fighters, and had begun that process with Dora subvariants and Ta152C tooling just as factories were being overrun by Allied troops. Clearly the last Anton was always going to be the A-9 but it was supposed to have the 801F engine.


Greg also brought up a really good point which again is often incorrectly reported. The amazing "rolling directional change" of the Anton was not in any way related to its manoeuvrability per se, it was a controlled stall, which only an experienced pilot could manage. The Anton was a shade inherently unstable, one of only very few fighters of the period that are (MiG-1/3 series do this also but not as pronounced), if you go with a stall out in a power on high alpha on the right wing (I don't know how a military pilot would express this manoeuvre), you backflip, drop a few hundred metres in a flash and wind up facing any direction you want, or you just go into a crazy spin and meet the ground. You know, depending. It's an escape manouevre, using a quirky stall. In outright manoeuvrability stakes later Spits and Tempests match up nicely agains the Anton under extensive wartime comparative evaluations, which are published and available.

In the Allied pilot reports of mid 44 onwards it was more common to find Antons flying low and slow, their recruit pilots only willing to do very soft manoeuvres when bounced. Messer pilots would tend to put up more of a fight, and rarely cruised low and slow unless in formation. Given both housed diminishing and poorly trained crews, one must assume the Anton was a little intimidating for a fresh pilot, which isn't surprising I guess if they've ever experienced that quirky stall unexpectedly.

 

[Siegfried]

There is an interesting article here by Roy Fedden (The Bristol engine designer) who went on a mission in defeated Germany to investigate German engine developments.

engine | piston-engine development | air-cooled radial | 1945 | 2394 | Flight Archive

It seems BMW were still developing the BMW 801F for 2600hp (some sites say 2700hp) I believe (just from reading other peoples posts) the technology involved 3 speed superchargers of improved performance perhaps even 2 stages and perhaps even inter-cooling.

I assume had it appeared it would have been installed on a FW 190 and that this would have been designated as an FW190A-10.

The FW 190A-10 was also rumoured to be getting an enlarged wing. If this was derived from the Ta 152C it would explain the reference to steal spars (which some claimed were armouring for ram attacks) but I think would've just been for material substitution.

It's worth noting that one area of technology to be applied to the BMW 802 was variable valve timing on the exhausts. This would have fulfilled the role of valve overlap and inlet manifold tuning of the DB605 ie scavenging over end gases and resonance loading.

I wonder if there was plans to apply this technology to the 801?

 

[Milosh]

Interesting vanir as a Fw190 expert says:

"The BMW801F series was produced and flew in significant numbers."

Fw 190 A-9 performance with BMW 801F-1 and Fw 190 A-10 - Topic

 

[davparlr]

Check out the P-80A performance tests on the Mike Williams site ww2 performance testing. I was suprised that the P-80A was noticeably slower than the Me 262 in 1946 tests except at very high altitudes where the Jumos didn't perform well. No match for a P-80C of a few years latter. Of course the allies weren't really trying after Japan surrendered.

This is a repeat of a previous post on another thread

P-80 Performance

Like the F4U-4, the conflicting performance data on the P-80 is confusing, and commentaries on the P-80 referencing unavailable books and documents add to the confusion.

The comment that most confuses me is that the P-80 was tested against the Me-262 and was found wanting and so embarrassed the AF that the test results were withheld.

I bought "Arrow to the Future" by Walter J. Boyne and he indeed makes the statement that test were conducted by a Al Boyd and the test results were only recently found that showed the Me-262 "had better speed, rates of climb at different altitudes, and turning radius and that this data was "suppressed". He also referred a book "The Lockheed P-80", which I ordered and now have. That information surprised me in two ways. First, in 1946, military budgets were being decimated. Typically, today, the AF emphasizes it aircraft short comings in order to scare congress into more money to develop new fighters, the XP-86 was in the concept cycle at this time and may have benefited from a poor review of the P-80. Of course times do change and maybe the AF was concerned about cuts to the fighter program because of lack of performance.

The second issue I have is with other data I have on the P-80 that tends to contradict the possibility of such poor performance. The Me-262 may have out performed the P-80 but shouldn't have embarrassed it. First, the XP-80, which was a bit smaller than the XP-80A, was able to do 502 mph, or only 38 mph less than the Me-262 with 62% of the thrust of the Me-262. In addition the XP-80A, with 4000 lb thrust was able to do 553 mph. The P-80 design was definitely clean.

Data review of my own data, "Spitfireperformance", and other googled sites revealed several data source for the two planes. These are the data source I have found for the Me-262.

Spitfireperformance document on British test on German jet propelled aircraft. Although they claim to reflect performance of data provided by Germans, it has lower performance levels for the Me-262 and the thrust appears low.

German documents on speed of Me-262 with the Jumo 004B engine. This is the speed I will show although it appears faster airspeeds at lower levels than other sources.

Russian data that appears as just published data. I will show climb data from this site since it conforms to other sources.

Me-262 Pilot Debrief . German pilot Hans Fey who apparently flew acceptance test on the Me-262 and stated that minimum airspeed was 515 mph at some altitude below 13,000 ft., which is quite a bit below the airspeed stated in the German document above.

Arrow to the Future, a book on Me-262 by Walter J. Boyne which was a bit of a disappointment in performance data. What it did show was standard data points. It did show that the climb rate of the Me-262 was 3937 ft/min at SL.

This is the data source I have found for the P-80.

From Spitfireperformance:

3 December, 1946 test by AAF on airspeed comparison of production P-80A vs modified wing tips and nose. Document is signed by the afore mentioned Col. Albert Boyd. This aircraft was flown with the J-33-11 engine.

7 November, 1946 test by AAF on surface treatments. Document is signed by Col. Albert Boyd.

14 February, 1947, test by AAF on best, worst and average P-80A with J-33-9 engine
Document is signed by Col. Albert Boyd.

The P-80 Shooting Star, a book by E.T. Wooldridge, which shows a performance comparison of the P-80A versus the XP-84. While this data referenced an AF memorandum, I did not use this data. It showed a much higher speed than some of the other tests, including 562 mph at sea level.

So this is basically what I have.

Me-262 per German document for airspeed, common data for climb, and for the P-80A, with J-33-9/11 engines. The two P-80 engines were interchangeable and were rated at 3570 lbs thrust.
For airspeed, I made four comparisons based on spotty data. Me-262 (1) is worst case based on test pilot report that min airspeed was 515 mph and other airspeed estimates based on delta to best performance. Me-262 (2) is best case based on German data. For the P-80, (1) is worst case per test and (2) is best case.

Airspeed

SL
Me-262 (1) 515
P-80 (1) 520
Me-262 (2) 521
P-80 (2) 548

10k
Me-262 (1) 520
P-80 (1) 524
Me-262 (2) 531
P-80 (2) 544

20k
Me-262 (1) 529
P-80 (1) 523
Me-262 (2) 540
P-80 (2) 531

30k
Me-262 (1) 509
P-80 (1) 505
Me-262 (2) 518
P-80 (2) 510

40k
Me-262 (1) NA, above Me-262 ceiling
P-80 (1) 481
Me-262 (2) NA, above Me-262 ceiling
P-80 (2) 493

Climb

SL
Me-262 3960 ft/min
P-80 (1) 4300
P-80 4640

20k
Me-262 2160
P-80 (1) 2500
P-80 2830

30k
Me -262 1080
P-80 (1) 1650
P-80 1910

Ceiling
Me-262 37,560 ft
P-80 45,000

Looking at this data, the lowest performing P-80A is equivalent to the poorest performing Me-262 in airspeed and the best performing P-80A is equivalent to the best Me-262 in airspeed. In both cases, the P-80A is superior to the Me-262 in climb. It also must be noted that the P-80 has over a mile more ceiling than the Me-262. This, as demonstrated in Korea by the Mig-15, is a significant advantage.


In my opinion, the P-80A with specified performing of J-33-9/11 would be very competitive to the Me-262 in the fall of 1945, certainly to the extent that the P-80 would be produced in considerably more quantity than the Me-262. With the higher ceiling, the P-80 could exploit higher energy levels.

Why the disparity in the reported flight test pilots and the concern about the performance compared to the Me-262? Well, there may be a couple of reasons. One, which I think is the case, is that the engine performance of the early engines was erratic and difficult to measure, and that the P-80 used for reference just did not perform. This was a case in one of the test documents where an engine had to be replaced. Two, the Me-262 that was tested performed quite a bit better than all the referenced data.

It must be noted that I am not in possession of the flight test data of the AAF testing of the Me-262.

 

[vanir]

Interesting vanir as a Fw190 expert says:

"The BMW801F series was produced and flew in significant numbers."

Fw 190 A-9 performance with BMW 801F-1 and Fw 190 A-10 - Topic

It's an old debate, dealt with at various sites by the likes of Crumpp using documented primary sources (including an almost complete record of Focke Wulf minutes of company meetings for the entire war). Place to go for reference will be LEMB, there's undoubtedly past threads there on the subject which will be far more reliable than Il2 gaming site.

There were two primary base engine alternatives to the D2 produced and fitted the A/F-9 and in some instances (rare) A/F-8. Both were based on 801E/F development but no 801F were serially produced and there are extensive examinations of the TH, TQ, etc. powereggs which were fitted, essentially they're rebuilt D2 engines using the benefits of 801F research and development, they do vary in which components are fitted. Those models also both received some benefits of Ta152 preproduction, like new props and tailplanes.

 

[Milosh]

vanir, Kettenhunde = Crumpp

 

[Siegfried]

This is a repeat of a previous post on another thread

Why the disparity in the reported flight test pilots and the concern about the performance compared to the Me-262? Well, there may be a couple of reasons. One, which I think is the case, is that the engine performance of the early engines was erratic and difficult to measure, and that the P-80 used for reference just did not perform. This was a case in one of the test documents where an engine had to be replaced. Two, the Me-262 that was tested performed quite a bit better than all the referenced data.

It must be noted that I am not in possession of the flight test data of the AAF testing of the Me-262.

Thanks for that data. The early P-80A, I believe, came with 3 different noses, some narrower that improved speed. I suspect there were also engine variations and mods and also test conditions eg is sea level really sea level or ground level somewhere 1000-2000ft up; morover temperature greatly influenced speed of the early jets.

The Boyne book also mentions Gert Lindener (I think that was his name) who was an Me 262 test pilot noting that a good example of an Me 262 could achieve 560mph. This is believable as build quality was generally atrocious, many were built without jigs and of course variations in thrust with engines also occur. Hence the spread of 520 possibly to as much as 560mph when a good airframe met a good pair of engines. I suspect 'variation control' in the US product was much better.

The Me 262 did quite well, considering it was a somewhat aged airframe (due delayed engines) when it entered service and that the two engines had little more thrust than the single engine of the P-80. To me its always looked like it would have a low roll rate due to the inertia of those massive jet engines. However it could apparently out turn a P-51D (not in radious of circle but by flying around the larger circle faster so it could do some tricks. The airfoil sections of the Me 262 were quite thin and advanced however and the presence of slats meant no lift robbing and shock wave forming wingtip washout was required.

The Me 262 also wasn't standing still. The Jumo 004D engine was slated for it; supposedly of 1100kg thurst or 1050kg depending on source. thats about a 22% or 15% increase in thrust.

There were a couple of technical advances comming on the Jumo 004 engine.

1 The first was the "Bescheuningungs ventile", ie the "accelerator valve". This was slated for troop service entry in Middle April 45. The Jumo 004B4 had a crude control sytem split into two independant sections. The first section used engine RPM and inlet pressure to move the variable area nozzle in an attempt to maintain constant combustion chamber pressure irrespective of altitude, RPM, mass flow etc. The other was the crude fuel control system which used an allspeed centrifugal governor. Push the throttle it acts on the governor by spring. This opens a valve to deliver more fuel to the engine till desired RPM is reached. Move the throttle it too fast and and the fuel overdoses and your burn through combustion chambers and shed turbine blades or go the other way and you flame out. A problem on the allied engines as well but the poorer german materials and made it worse for them. The accelerator valve was an aneroid across the compressor to measure actual pressure/flow conditions and moderate the fuel flow untill actual air flow had truely increased/decreased. The BMW 003 did have this valve.

A lot of the Jumo 004's reliabillity issue was caused by this.


***********************
This is from the LUftwaffe Cheif technical intelligence officer's official war diary:

109 - 004 (Junkers: Jumo oo4 jet engine, AOB)
KTB-TLR part 8

Vorschau am Monatsanfang 1000, am Monatsende 900, geliefert 876.

Mehrfache Forderung eines Einbaues eines Beschleunigungsventils, welches die Aufgabe hat, unzulässige Überheizung des Triebwerks bei plötzlichem Gas geben zu vermeiden. Einführung bei der Truppe und soweit vorhanden in der Serie bis Anfang April 1945 vorgesehen.

Fehlen von Ersatzteilen 004 macht sich bei der Truppe störend bemerkbar. General Kammler befiehlt, daß Ersatzteile unmittelbar zum Klarmachen von Einsatzflugzeugen, ohne Rücksicht auf Serienbelange, zu liefern sind.

Google Translation slightlytidied:

109-004 (Junkers Jumo jet engine, AOB)
Preview at the beginning of the month 1000, at the end of the month 900, delivered 876th

Mass incorporation of an "accelerating demand valve", which has the task to avoid undue overheating of the engine type for sudden throttling. Introduction to the troops and to the extent specified there in the series until early April 1945.

Lack of spare parts makes 004 at the disturbing force. General Kammler ordered that replacement parts directly to Make Sure of operating aircraft are to be delivered without consideration of serial issues.
******************

2 a second modification were 'duplex nozzles'; at high altitude or low rpm flow rates is too low to ensure adaquete vaporisation of fuel, so these nozzles switch to a second oriface at low flow/pressures to ensure the engine is less likely to flame out at high altitude.

3 there were provisions for theromocuples to adjust fuel flow rate if heat got excessive. Little known of any controls built for this.

4 The Jumo 004D probably had a newer better compressor.

I would certainly say the Jumo 004 whether it was an upgraded Jumo 004b or a more improved 004d would be providing more thrust at higher altitude to some degree by mid 45 had development continued.

I would tend to think that the Me 262's small advantages in some areas would not be enough to be a game changer unless they managed to combine it with new weapons like the R4M missile with the EZ-42 gunsight linked by Elfe computer to a FuG 248 "Eule" or Pauke SD ranging radar; the latter probably only a laboratory device