Discussion about video - "P-51 Mustang vs. Fw 190 D-9"

[Mike Williams]

Further reading about the change over to 100 octane by the RAF and the increases in performance obtained therefrom:

Alec Harvey-Bailey, The Merlin in Perspective, (Rolls-Royce Heritage Trust, Derby, 1983), p. 85.
W.G. Dudek and D. R. Winans, excerpt from AIAA Paper No. 69-779, Milestones in Aviation Fuels, (Esso Research and Engineering Company, New York 1969.) p. 319.
A. R. Ogston, excerpt from History of Aircraft Lubricants (Society of Automotive Enginees, Inc. Warrendale, PA USA), p. 12.
Hundred Octane, Flight, No. 1631 Vol. XXXVII, The Outlook, March 28, 1940.
H. F. King, Fighter Station, With the Spitfires in Scotland, (Flight, No. 1631 Vol. XXXVII, March 28, 1940), pp. 290-295.
"Aero", Correspondance, (Flight, January 6th 1944), p. 22.
Air Commodore F. R. Banks, I Kept No Diary , Airlife Publications, Shrewsburg, 1978, Appendix II Fuel pp 234-236
Leo McKinstry, Hurricane, Victor of the Battle of Britain, (John Murrey Publishers, London, 2010), p. 87.
Leo McKinstry, Hurricane, Victor of the Battle of Britain, (John Murrey Publishers, London, 2010), p. 191.
Robert Schlaifer, Development of Aircraft Engines, (Harvard University, Boston, 1950), pp.220-223
Fuels and Lubricants Handbook: Technology, Properties, Performance, and Testing, (ASTM International, 2003). P. 89
Dik A. Daso, Doolittle: Aerospace Visionary, (Potomac Books, Washington D.C, 2003), p. 38.
Bill Gunston, Rolls-Royce Aero Engines, (Patrick Stephens Limited, 1989). p. 72.
Alfred Price, The Spitfire Story, (Arms and Armour Press Ltd., London, 1986), p. 74.
Dr. Alfred Price, Spitfire Mark I/II Aces 1939-41, (Osprey Publishing, 1996), p. 19.
Richard P. Hallion, "The American Perspective", in Paul Addison and Jeremy A. Crang (eds), The Burning Blue. A New History of the Battle of Britain (Pimlico, London 2000), p. 84.
David Ross, The Greatest Squadron of Them All, The Definitive History of 603 Squadron, RAauxAF, (Grub Street, London, 2003), p. 125.
Gavin Bailey, The Arsenal of Democracy: Aircraft Supply and the Evolution of the Anglo-American Alliance, 1938-1942, (Edinburgh University Press, 2013), p. 104.
Sir Stanley Hooker, Not Much of an Engineer, (Airlife Publishing, Ramsburg, Marlborough, Wiltshire, 2002), p50.
Wing Commander George Kerr, Time's Forlock, (The Shell Petroleum Company Limited, London, 1948). pp. 36-38.
Peter Pugh, The Magic of a Name, The Rolls-Royce Story, The First 40 years, (Icon Books, London, 2000), pp. 189-190; 229-230.

 

[Mike Williams]

I think I'd start a graphical comparison with the data sets shown below and move on from there. One less than desirable issue is that the P-51 data derives from a USAAF test at Wright Field of an actual P-51D aircraft, serial number 44-15342, whereas the Fw 190D-9 data is from engineering estimates from Focke-Wulf Flugzeugbau's Abt.: Flugmechanik-L. Flight trials of Fw 190 D-9s can be found here and are useful, however, the data charted is insufficient to show performance at 1.8 ata throughout the full range of altitudes with level speed, climb rate and climb time. While it was concluded by the Power Plant Laboratory of Materiel Command's Engineering Division that the V-1650-7 engine would satisfactorily comply with a 75" Hg manifold war emergency rating with 150 grade fuel and P-51Ds are reported to have operated at 75" Hg., such as shown in this Encounter Report from Chuck Yeager, 72" Hg. appears to be the generally accepted limit in the 8th AF beginning in June 1944. An increase of boost from 67" hg. to 72" on the P-51D should increase power to about 1820 hp and increase speeds below full throttle height by around 7 mph. RAF Mustangs operated at 80" Hg. / +25 lb.sq. in. boost. A. & A.E.E. reported - "Use of +25 lb/sq.in. instead of +18 lb/sq.in. boost increased the True Air Speed below full throttle height 25 mph."

 

[Mike Williams]

Level speed charts showing the impact of increased boost with the P-51 D made possible by 150 grade fuel.

 

[BiffF15]

Level speed charts showing the impact of increased boost with the P-51 D made possible by 150 grade fuel.

View attachment 602605View attachment 602606

Mike,

Do you have the limits around the Fw-190D-9 MW? How much was carried, when it could or could not be used, and limits (time or otherwise)?

Cheers,
Biff

 

[Mike Williams]

Mike,

Do you have the limits around the Fw-190D-9 MW? How much was carried, when it could or could not be used, and limits (time or otherwise)?

Cheers,
Biff

Hello Biff,

Dietmar Hermann wrote the following: "In October the number of Fw 190 D-9s on strength with the Gruppe rose to 68. Of these, 53 had been converted to 1,900 h.p. and one was delivered by Focke-Wulf with the MW 50 system. The remaining 14 were in the process of being converted and completion was imminent."

"In production aircraft it was planned that the MW 50 system could be used to draw fuel or methanol/water from the 115-liter tank. On account of delivery difficulties, however, it was decided to use the tank with methanol-water only, and this was dubbed the "Oldenburg System" (see III./JG 54). This system was installed in production aircraft beginning in November 1944."

"By the end of December 1944 there were 183 Fw 190's in operation with the increased performance modification, and 60 more had been delivered with the MW 50 system and were at the point of entering service."

I'm not sure of duration or limits yet, will check.

 

[davparlr]

Level speed charts showing the impact of increased boost with the P-51 D made possible by 150 grade fuel.

View attachment 602605View attachment 602606

I have a chart that shows FW190 A-9, D-0, and TA152 H-1, and on that chart it shows the D-9 with some better airspeed performance than your chart, e.g., SL speed shown on posted chart was about 375 mph whereas my chart has about 388 mph (most of it is similar). In any event, it appears to me that both of these aircraft were very similar in performance with maybe a slight advantage to the D-9 up to about 20k due to slightly better climb and the P-51D having a definite advantage above 25k due to better climb and significantly better airspeed. However, due to uncertainties of manufacturing tolerances in engines, engine tuning levels, propellers, streamlining, and error tolerances of test equipment, and test condition variations, we are really trying to make a precise cut with a dull axe.

 

[BiffF15]

Hello Biff,

Dietmar Hermann wrote the following: "In October the number of Fw 190 D-9s on strength with the Gruppe rose to 68. Of these, 53 had been converted to 1,900 h.p. and one was delivered by Focke-Wulf with the MW 50 system. The remaining 14 were in the process of being converted and completion was imminent."

"In production aircraft it was planned that the MW 50 system could be used to draw fuel or methanol/water from the 115-liter tank. On account of delivery difficulties, however, it was decided to use the tank with methanol-water only, and this was dubbed the "Oldenburg System" (see III./JG 54). This system was installed in production aircraft beginning in November 1944."

"By the end of December 1944 there were 183 Fw 190's in operation with the increased performance modification, and 60 more had been delivered with the MW 50 system and were at the point of entering service."

I'm not sure of duration or limits yet, will check.

Mike,

Thanks! I remember reading somewhere exactly what you quoted. The reason I ask is the Fw-190D-9 had a little better performance than the P-51D in the 12-20k'ish block, and I'm wondering how much of that was due to the MW-50 / Oldenburg System (how much and just as importantly for how long). I also have read, as davparlr mentioned, that the seals around the firewall to cowling were very important as they added about 10 or so MPH (IIRC). Just trying to figure out what they Allies were going up against when they did meet the Long Nosed Fw's (between cowl seal, MW50, and fuel you could have a pretty good spread on your opponents top speed / power out.

Cheers,
Biff

 

[Mike Williams]

I have a chart that shows FW190 A-9, D-0, and TA152 H-1, and on that chart it shows the D-9 with some better airspeed performance than your chart, e.g., SL speed shown on posted chart was about 375 mph whereas my chart has about 388 mph (most of it is similar). In any event, it appears to me that both of these aircraft were very similar in performance with maybe a slight advantage to the D-9 up to about 20k due to slightly better climb and the P-51D having a definite advantage above 25k due to better climb and significantly better airspeed. However, due to uncertainties of manufacturing tolerances in engines, engine tuning levels, propellers, streamlining, and error tolerances of test equipment, and test condition variations, we are really trying to make a precise cut with a dull axe.

Hello davparlr,

The chart Focke-Wulf Flugzeugbau, Horizontalgeschwindigkeit über der Flughöhe mit Sondernotleistung, 3.1.45 has a curve that shows SL speed as ~388 mph, however, I'm uncertain if that curve belongs to a 190 D-9 or Ta 152 since the curves intersect below 2 km. In any event, the performance shown of the Fw 190D-9 in that chart assumes 2.02 ata boost, the aircraft without ETC belly rack, with retractable inner landing gear doors, with sealed engine gap and with skin surface filled and smoothed.

I've worked with Dietmar Hermann on this subject and think he's got it about right:

"I haven't read or heard that the D-9 was tested with the Jumo 213 and C3 fuel. I know that at the beginning of development Focke-Wulf made a distinction between the normal Jumo 213 and the Jumo 213 with 100 octane fuel. I think that there was not a problem with the engine; rather there was a problem of the fuel's availability.In my book I have published one chart from 3.1.45 (page 154) showing FW 190 D-9 performance with B4 fuel with MW 50 injection operating at 2,02 ata (Sondernotleistung ). However, I have no evidence showing that 2,02 ata was enabled by the end of the war. I think that the D-9 was flown either with the 1900 PS update or with MW50 injection (2100 PS).
The development announcement of the D-9 said that all D-9 were delivered with the ETC 504 and the 170 l or 300 l drop tank (Entwicklungsmitteilung Fw 190 D-9, Blatt XV b2 and b3 from 31 May 44 and renewed at 20 June 44). The first test report of FW 190 D-9 serial number 210002 states that the D-9 lost 8..10 km/h. with the ETC 504 and the fixed wheel flaps (delivery condition).

From Fw 190 " Long Nose" , pg 103: "Focke-Wulf conducted experiments with a Fw 190 D-9 (WNr. 210 002, TR+SB) (Flugbericht Fw 190 D-9/210002 Nr. 3) in an attempt to further increase the performance of production aircraft. Gaps in the engine cowling fore and aft were sealed with rubber. In the course of these experiments an increase in speed of 17 km/h was achieved at combat power. Focke-Wulf subsequently advised the manufacturing plants to pay special attention to proper sealing of the engine compartment pending approval by E-Stelle Rechlin. Rechlin rejected the idea of rubber seals for the engine compartment, however."

D-9 production aircraft did not have the slit sealing (engine gap seal). I have the information from a document named "Lfd. Entwicklungsarbeiten Fw 190/Ta152" from 8.1.45 updated 20.3.45 with the handwritten statement "24.3. Rechlin lehnt ab!". So I think that this was the expected answer about the previous troubles during the Focke-Wulf testing. (Test report No. 3 of Fw 190 D-9 210002 dated 24.10.44 shows a 13 km/h difference at SL operating at 1.8 ata between aircraft with sealed and unsealed engine gaps (595-608) - Ed.).

Flight Report Nr. 4 of Fw 190 D-9/210002 presented the following results: Operating at 1,75 ata, a maximum speed of 606 km/h (376 mph) at ground level was obtained. The maximum speed in the first gear was 650 km/h (404 mph) at 2,7 km (8858 ft.).The condition of the aircraft was as follows: D-9 production condition with methanol installation, surface smoothed/primed and polished, seams & cracks sealed, operable wheel flaps, gap at engine sealed (D-9 Serienzustand mit Methanolanlage, Oberfläche gespachtelt und poliert, Spalte abgedichtet, bewegliche Radklappen, Spalte am Triebwerk abgedichtet.) These values did not quite reach the characteristic curve from the comparison dated 15.12.44.

So we can state: D-9 without engine sealing - 15 km/h; with ETC 504 + fixed wheel covering about -10 km/h. This indicates that the D-9 reached the following speeds - minimum:
•606 km/h (377 mph) at sea level with MW 50 injection and engine sealing; without ETC 504 and variable wheel covering.
•591 km/h (367 mph) at sea level with MW 50 injection; without engine sealing, ETC 504 and variable wheel covering.
•581 km/h (361 mph) at sea level with MW 50 injection, ETC 504 and fixed wheel covering; without engine sealing."

The realm of what-if or could-have-been is beyond the scope of my exercise and analysis.

 

[Mike Williams]

Mike,

Thanks! I remember reading somewhere exactly what you quoted. The reason I ask is the Fw-190D-9 had a little better performance than the P-51D in the 12-20k'ish block, and I'm wondering how much of that was due to the MW-50 / Oldenburg System (how much and just as importantly for how long). I also have read, as davparlr mentioned, that the seals around the firewall to cowling were very important as they added about 10 or so MPH (IIRC). Just trying to figure out what they Allies were going up against when they did meet the Long Nosed Fw's (between cowl seal, MW50, and fuel you could have a pretty good spread on your opponents top speed / power out.

Cheers,
Biff

Hello Biff, as noted above Flugbericht Fw 190 D-9/210002 Nr. 3 discussed trials of an aircraft with the engine seals and noted "During these flights the seals between engine and wings pulled out and then were torn off. It was also noticed that exhaust gases caused minor fire in spots. Therefore, an improvement of the sealing within this area is necessary."

To reiterate from Dietmar "D-9 production aircraft did not have the slit sealing (engine gap seal). I have the information from a document named "Lfd. Entwicklungsarbeiten Fw 190/Ta152" from 8.1.45 updated 20.3.45 with the handwritten statement "24.3. Rechlin lehnt ab!". "

My view of the condition representative of standard production Fw 190 D-9's during 1945 is as follows: Jumo 213A operating at 1.8 ata with B4 fuel & MW 50, equipped with ETC 504, main wheel fairing doors absent/fixed and engine gap not sealed. The curve best fitting the condition of a standard production Fw 190 D-9 is curve 4 of the Focke-Wulf Fw 190 D-9 chart dated 11.3.45 That's the curve I charted above.

 

[BiffF15]

Hello Biff, as noted above Flugbericht Fw 190 D-9/210002 Nr. 3 discussed trials of an aircraft with the engine seals and noted "During these flights the seals between engine and wings pulled out and then were torn off. It was also noticed that exhaust gases caused minor fire in spots. Therefore, an improvement of the sealing within this area is necessary."

To reiterate from Dietmar "D-9 production aircraft did not have the slit sealing (engine gap seal). I have the information from a document named "Lfd. Entwicklungsarbeiten Fw 190/Ta152" from 8.1.45 updated 20.3.45 with the handwritten statement "24.3. Rechlin lehnt ab!". "

My view of the condition representative of standard production Fw 190 D-9's during 1945 is as follows: Jumo 213A operating at 1.8 ata with B4 fuel & MW 50, equipped with ETC 504, main wheel fairing doors absent/fixed and engine gap not sealed. The curve best fitting the condition of a standard production Fw 190 D-9 is curve 4 of the Focke-Wulf Fw 190 D-9 chart dated 11.3.45 That's the curve I charted above.

Thanks Mike,

Looking at that chart, and the one further up that shows TAS comparisons between the P51D and the FW190D-9 it looks like the only "place" the FW has a performance advantage is the diamond roughly from 12 to 21k, with the biggest split in favor of the FW occurring in the 18k'ish altitude. Combined with the MW injection, which doesn't last forever, some of that advantage would be removed after it expires or is used up.

It's really surprising that with the performance gain from the wheel doors and the engine seals that they weren't mandated. I don't know what that decision was based on (majority of the fights not in the absolute high speed regime, therefor those mods were of little use in "most" engagements?) or the skill of the new pilots were such that the speed gain would not have been used wisely if at all.

With this knowledge, and in an engagement with a Fw-190D in the "diamond" and: A. Offensive, don't let up but realize the performance delta. B. Neutral, unless your adversary makes a gross error, treat him as better performing P51D, or in other words don't push it and if in doubt make the decision to leave early. C. Defensive, work the fight into your strengths (down), leave or go offensive (if the opportunity occurs) and / or get help.

The age old advantage of fighting over your home turf (Fw190D) allows for pushing your fuel and landing practically anywhere should the situation dictate. Disadvantage is your fighting over your country and it's getting bombed day and night.

Cheers,
Biff

 

[davparlr]

My information shows the D-9 having a slightly better climb rate up to about 15k but my data may be off since I don't read German. Another advantage that the P-51D has is endurance. The P-51D has a combat fuel load of 184 gallons vs the D-9 of 138 gallons and since the D-9 did not go into production until August of '44, it's reasonable to assume forward European airfields were available for the P-51, so no long trip back to England and much more time over the battlefield.

 

[BiffF15]

My information shows the D-9 having a slightly better climb rate up to about 15k but my data may be off since I don't read German. Another advantage that the P-51D has is endurance. The P-51D has a combat fuel load of 184 gallons vs the D-9 of 138 gallons and since the D-9 did not go into production until August of '44, it's reasonable to assume forward European airfields were available for the P-51, so no long trip back to England and much more time over the battlefield.

Also remember that the smaller the fuel load the smaller the perf hit. A lot of Bf-109 & FW-190 performance versus the P-51 came from the smaller airframes / fuel tanks designed for shorter duration flights.

Cheers,
Biff

 

[Mike Williams]

My information shows the D-9 having a slightly better climb rate up to about 15k but my data may be off since I don't read German. Another advantage that the P-51D has is endurance. The P-51D has a combat fuel load of 184 gallons vs the D-9 of 138 gallons and since the D-9 did not go into production until August of '44, it's reasonable to assume forward European airfields were available for the P-51, so no long trip back to England and much more time over the battlefield.

I agree that the Fw 190 D-9 was a better climber than the P-51D at low altitudes , even when the P-51 was operating at 72" Hg. (see attachment). I expect the D-9 was better in roll at some speeds and maybe acceleration too at times. I really wouldn't want to be stall fighting these aircraft but if it came to it I think the Mustang would have an advantage. Performance is probably close enough that other things like unit tactics, gyro gunsights, G-suits, tail warning radar, ground control, weight of numbers, etc. might be the deciding factors.

 

[GrauGeist]

Also remember that the smaller the fuel load the smaller the perf hit. A lot of Bf-109 & FW-190 performance versus the P-51 came from the smaller airframes / fuel tanks designed for shorter duration flights.

Cheers,
Biff

I also recall reading that by late '44 and early '45, Luftwaffe aircraft often times didn't have a full loadout of fuel onboard due to logistics and supply issues.

 

[davparlr]

Also remember that the smaller the fuel load the smaller the perf hit. A lot of Bf-109 & FW-190 performance versus the P-51 came from the smaller airframes / fuel tanks designed for shorter duration flights.

Cheers,
Biff

Basically, most (?) European fighters were point defense fighters , after all almost everything is pretty close. The most impressive feature of the P-51 was that it could fly 600 miles, engage these lighter defensive fighters with full combat fuel and with formidable effect and then fly 600 miles home. This is a general statement and general statements are often dangerous, most flight test are performed at combat weight which usually means full internal fuel, except the P-51 which has an internal extended range tank. So, to really compare airframe vs airframe to the Fw 190 D-9, the P-51 would have to be tested at 138 gallons of fuel instead the normal tested 180 gallons, or about 250 lbs lighter. So, yes added fuel affects performance but these test include that effect.

 

[davparlr]

I also recall reading that by late '44 and early '45, Luftwaffe aircraft often times didn't have a full loadout of fuel onboard due to logistics and supply issues.

Which certainly would improve performance but would also negatively affect combat time. Fuel on the ground is one of the most useless thing in flying like runway behind you and altitude above you.

 

[BiffF15]

Basically, most (?) European fighters were point defense fighters , after all almost everything is pretty close. The most impressive feature of the P-51 was that it could fly 600 miles, engage these lighter defensive fighters with full combat fuel and with formidable effect and then fly 600 miles home. This is a general statement and general statements are often dangerous, most flight test are performed at combat weight which usually means full internal fuel, except the P-51 which has an internal extended range tank. So, to really compare airframe vs airframe to the Fw 190 D-9, the P-51 would have to be tested at 138 gallons of fuel instead the normal tested 180 gallons, or about 250 lbs lighter. So, yes added fuel affects performance but these test include that effect.

I agree that most of the Euro equipment would fall under the point defense fighter umbrella. Heck, most still fall under that today. I'm also very aware of the Mustangs unique ability to achieve both a large fuel load, and "high fuel mileage" (TIC). I've also pointed out that a comparison between the Fw & Me are a bit apples to oranges as the Mustang is saddled with fuel, oxygen, or weight to allow it to fly much greater distances than its German equivalents. This previous statement is what is missing most of the time when guys do compare them, or a lack of understanding the difference between the charts and the reality of practical use (or uses).

Probably the most accurate representation would be to test a Mustang at a bit over half fuel, vice a Bf or Fw with about 3/4s fuel as that is how they would meet over Berlin (or there about). That would be a test of the plane itself. The next would be a comparison of the average flight time prior to engaging in combat between the pilots of the various militaries (think this would be an eye opener particularly going month by month for the entire war (Pacific as well).

 

[Koopernic]

I think I'd start a graphical comparison with the data sets shown below and move on from there. One less than desirable issue is that the P-51 data derives from a USAAF test at Wright Field of an actual P-51D aircraft, serial number 44-15342, whereas the Fw 190D-9 data is from engineering estimates from Focke-Wulf Flugzeugbau's Abt.: Flugmechanik-L. Flight trials of Fw 190 D-9s can be found here and are useful, however, the data charted is insufficient to show performance at 1.8 ata throughout the full range of altitudes with level speed, climb rate and climb time. While it was concluded by the Power Plant Laboratory of Materiel Command's Engineering Division that the V-1650-7 engine would satisfactorily comply with a 75" Hg manifold war emergency rating with 150 grade fuel and P-51Ds are reported to have operated at 75" Hg., such as shown in this Encounter Report from Chuck Yeager, 72" Hg. appears to be the generally accepted limit in the 8th AF beginning in June 1944. An increase of boost from 67" hg. to 72" on the P-51D should increase power to about 1820 hp and increase speeds below full throttle height by around 7 mph. RAF Mustangs operated at 80" Hg. / +25 lb.sq. in. boost. A. & A.E.E. reported - "Use of +25 lb/sq.in. instead of +18 lb/sq.in. boost increased the True Air Speed below full throttle height 25 mph."

View attachment 601811View attachment 601812View attachment 601813

I'll make several points below regarding this curve and also note that the Fw 190D9 was an interim aircraft already being replaced by the Fw 190D12.

1 The primary difference between the P-51 (in blue) and the Fw 190D (in red) is that the Fw 190 D9 has a Jumo 213A engine with a single stage two speed supercharger whereas the P-51D has a two stage two speed supercharger. The Jumo 213A is operating at 1.8 atmospheres boost which is (1.8 x 30 = 54 inches of mercury) or (0.8 x 14.2 = 12 psig boost.

2 Following the red curve we see that the Fw 190D9 continues increasing in speed from 376mph at sea level till at 403mph / 7000 feet altitude the Fw 190D9's Jumo 213A changes from first gear to second gear and we see a slight bump. Boost of 1.8 ATA is maintained till 18,000ft when the air is only 60% of sea level and manifold pressure begins to decline with it causing a decline of both power and speed. From this we can surmise that the Jumo 213A supercharger can maintain aa compression ratio of about 3:1.

(Those talking of Lancaster's being used for day bombers should know that this decline happened at 16,000ft for the single stage Merlins and Lancaster operations would be at an ideal altitude for the Fw 190A. D and Me 109.)

3 The P-51 is operating at 67" of Mercury. That is 2.2 ata or 18psig. It follows the same trend except that the bump occurring at the change from 1st gear LF to MF second gear is huge as the supercharger looses efficiency and with it power and aircraft speed. The supercharger gains efficiency and continues to increase in speed till 26,000ft untill it too can no longer maintain pressure.. From this we can surmise that the Merlin supercharger can maintain a pressure ration of around 5:1. The intercooler on the Merlin also removed the heat generated by this huge compression ratio. The two stage Merlin really needed 3 speeds.

The Jumo 213A cant really compete above 18,000ft due to the single stage supercharger,

The Jumo 213A was capable of operating at around 2.0 ata and probably more though not released for service this would give 10% more power and that 115 or 140 L tank used for MW50 could in theory take Nitrous Oxide (or extra fuel) as appropriate for the mission. GM1 would increase speed to 443mph at 8000m (26400ft) for about 15-20 minutes. The P-51 has the advantage of 100/130 fuel and although B4+MW50 was roughly equal to 100/130 the Fw 190D9 seemed to perform better on C3 (98/130) rather than B4 (nominally 87 but usually around 91)

The speed curves from the old "Jagdhund" web site is archived here:
https://forums.eagle.ru/filedata/fetch?id=6558844
(ive often though this was Herman)

The Jumo 213A was really a bomber engine, (that was meant to be the Jumo 213C which featured emergency boost and the mountings for a motor canon). The Jumo 213A started appearing on Ju 188A in April 1944 as well as Ju 88S3 (with GM-1) and Ju 88G6 as well as some He 111 H21. It became available for fighter use with the cancellation of bomber production.

It produced 1750 hp. but to make it ready for a fighter it was given improved supercharger with better fluid dynamics, and an emergency boost system referred to as 'increased boost' to produce 1900hp and latter still the introduction of MW50. There were two MW50 system, the Oldenburg System that was retrofitted by Luftwaffe maintenance crews that worked by using supercharger pressure to blow MW50 from the tank into the eye of the supercharger and a high pressure Junkers system that used a pump and was fitted by Junkers technicians. This high flow high pressure system had better performance. This seemed to give 2100hp. There was a Jumo 213AG which produced 2240 seemingly by a modified supercharger optimised for sea level.

As pointed out the Jumo 213A was an interim engine. A few (I think 5-12) Fw 190D12 were delivered to the Luftwaffe. This featured the Jumo 213F engine that had a 3 speed two stage supercharger without intercooling. Speed was 454mph at 30,000ft using C3 + MW50. The provision of motor canon allowed the deletion of the drag producing cowling guns.
Due to problems in designing and producing a enlarged radiator the radiator of the Fw 190D9 was used. This was insufficient and forced the cooling gills to open after 30 seconds at full power which reduced the speed though climb, turn and altitude was still much better as power was maintained.

Rather than engineering an new radiator it was decided to wait for the Jumo 213EB which featured an intercooler, much more power and could be installed in to both the Fw 190D and the Ta 152. Fw 190D12 EB were expected to achieve 488mph without GM1.

The Jumo 213E used in the Ta 152 did not fit into the Fw 190D hence the use of the Jumo 213F. The first 200 Jumo 213E0 and Jumo 213F0 had a weak supercharger shaft which locked out 3rd gear and saved many an allied pilot.

The Fw 190 was getting old hence it was being upgraded into the Ta 152C and Ta 152H with 65% parts commonality with the Fw 190 however the Fw 190D would continue in production because it low wing area gave it a speed advantage at low altitude which made it suitable for ground attack. The Fw 190D12 EB would have had the TSA 2D toss bombing sight and the deletion of outer wings guns allowed fuel tanks to be positioned there.

 

[gmsw7]

Hi

One or two commenters say that the higher octance fuel with higher compression ratio would produce more power and faster climb rate but not greater horizontal speed. If someone could explain that I would appreciate it.

thanks

 

[tomo pauk]

Hi

One or two commenters say that the higher octance fuel with higher compression ratio would produce more power and faster climb rate but not greater horizontal speed. If someone could explain that I would appreciate it.

thanks

An engine that has greater compression ratio and uses high octane fuel will make more power vs. the otherwise same engine with lower compression ratio and high octane fuel. More power usually means more speed., for the same aircraft.