Realistic max speeds WW2 fighters / Speeds of the late 109s

[Milosh]

The unit of JG11 was an operational test unit for 1.98ata boost. Rechlin was running its own testing. Afair the JG11 unit was having its share of problems as well.

This be the order, OKL, GdJ-Grp. Qu-, Br. B. Nr. 1561/45 g.Kdos. von 20. März 1945.

I have never seen an original copy of this order, only someones typed version and even that has changed over time regarding the a/c.

I have only seen speculation and supposition, even going as far as to other units besides the 4 Gruppen, on the use of 1.98ata boost.

 

[kettbo]

Now with some non-metric numbers in BOLD. 8)


Some time now for me to poke around the Kurfurst site

Kurfürst - Daimler-Benz A.G. - Horizontalgeschwindigkeiten mit MW 50 Leistung Me 109 GJ+FX.

G-6/AS looks to me like 690kmph at 7000m, 560 at 0m, 2800rpm 1.7ata, curve shows w/MW50
G-6/AS looks to me like 428mph at 22,965ft, 347mph at 0ft, 2800rpm 1.7ata, curve shows w/MW50

Kurfürst - Bf 109G-6 / DB 605 A

G-6 looks like 645 at 6500m, 520 at 0m, 2800 rpm at 1.42ata
G-6 looks like 400mph at 21,325ft, 323mph at 0ft, 2800 rpm at 1.42ata

Kurfürst - Leistungen Me 109 G-14/U4 mit DB 605 AM u. ASM.

G-14/U4 AM engine: 652at 5km, 647 at 6km, 557 at Sea Level 2800 rpm 1.685?? boost portly 3501kg, 2x13mm, mk 108 and 20mm cannon pods, ammo, mw50
G-14/U4 AM engine: 405mph at 16,404ft, 402.03mph at 19685ft, 346mph at Sea Level 2800 rpm 1.685?? boost portly 3501kg, 2x13mm, mk 108 and 20mm cannon pods, ammo, mw50

G-14/U4 ASM engine: 668 at 7.5km, 550 at Sea Level, 2800 rpm 1.685 ata 3546 kg !!!, 2x13mm, mk 108 and 20mm cannon pods, ammo, mw50
G-14/U4 ASM engine: 415mph at 24,606ft, 341mph at Sea Level, 2800 rpm 1.685 ata 3546 kg !!!, 2x13mm, mk 108 and 20mm cannon pods, ammo, mw50this will give me food for thought

I believe I saw the figure the cannon cost 8mph loss in speed (?) moslty in drag. The extra wt would hurt handling more than it hurt speed.
I also think I saw a note where the common MG 131 boils cost more speed loss than the underwing cannon! Someone please crucify me if I have this wrong.

And I believe a lot of the max speeds were at 10 minute rating (?) not emergency rating? Noted the use of "Sondernotleistung" which translates to Special Emergency Power, but not quite sure how this compares to American or British evaluation procedures or operational flying.

Would I be correct in saying that the K-4 and G-10 were in the 450mph/725kph speed capability with a good engine and decent build quality(?) at 2800rpm and 1.80ata?

 

[Juha]

Hello George
my info is
for Bf 109G-6, 1,42ata is the Start- und Notleistung, ie Take-off and Emergency power, allowed for 1 or 3 minutes, depending on the manual you looked, 1475hp,
530km/h at SL 640km/h (398mph) at 6.600m. With MW50, if this was installed later on, ie in practice G-14, 570km/h at SL

109G-10/R6 bad weather fighter with autopilot with Combat and climb power (30min) 500km/h at SL, 653km/h at 9000m. Max speed with Sonder 562km/h at sea level, 690km/h (429mph) at 7500m

K-4 (max 1.8ata / 1800hp)
combat and climb power (30min /1275hp at SL) 515km/h at sea level, 670km/h at 9.000m
Max with Sonder 580km/h at SL, 710km/h (441mph) at 7.500m.

Juha

 

[stona]

This document only specifies II./JG11 for provisional testing of the higher boost pressures.

http://www.wwiiaircraftperformance.org/me109/db-minute-6730.pdf

I haven't done a complete translation as I need to refer to a German friend who helps me with such things. You can see that the use of 1.98 ata boost is forbidden. There are complaints about fuel quality and a very unfavourable comparison of the Bf109 to the Mustang (in a German document!).

I'm sure I've seen a copy of that 20th March order somewhere. I know Kurfurst's site has a list of units that were supposed to adopt the higher boost. Unfortunately what the OKL was hoping for and what the units were being advised to do are not the same.
Just a week earlier Reparatur-Anweisung 2. Nachtrag Nr. 191/345 from Des Reichministers für Rüstung und Kriegproduktion,dated 14 March 1945,gives instructions for the adjustment of engine settings and it clearly gives 1.8 ata as the maximum boost allowed.

Some units would have received this instruction for higher boost after Bf109 production had ceased and they were receiving old G-6s from training units.

Cheers
Steve

 

[Tante Ju]

This document only specifies II./JG11 for provisional testing of the higher boost pressures.

http://www.wwiiaircraftperformance.org/me109/db-minute-6730.pdf

I haven't done a complete translation as I need to refer to a German friend who helps me with such things. You can see that the use of 1.98 ata boost is forbidden. There are complaints about fuel quality and a very unfavourable comparison of the Bf109 to the Mustang (in a German document!).

I looked at document, but where does say - provisional? It is decided that II/JG 11 is to provide field test of 1,98ata, maybe an interim test of 1,9ata until the engine fail, like stress test. Until it is complete, order of clearing is delayed. I think you need read whole paper.. it says lot more. In end they also say plan is to use 2,3 ata.

The document say that 1,98 ata was directly forwarded by Daimler Benz and Technical Office to troops, together with clearing of 1,8ata in same order, and engines were to set for 1,98ata at Troops. BTW General Engineer Paul is very strongly criticize this process, saying, that it is not right to forward rating and set engines to rating that are not satisfactory tested. This is January 1945 doc, speaking of past event, so I am fairly certain given this document that 1,98ata was used in December or earlier. This is why Gen. Ing. Paul makes strong criticism.

I'm sure I've seen a copy of that 20th March order somewhere. I know Kurfurst's site has a list of units that were supposed to adopt the higher boost. Unfortunately what the OKL was hoping for and what the units were being advised to do are not the same.
Just a week earlier Reparatur-Anweisung 2. Nachtrag Nr. 191/345 from Des Reichministers für Rüstung und Kriegproduktion,dated 14 March 1945,gives instructions for the adjustment of engine settings and it clearly gives 1.8 ata as the maximum boost allowed.

I think here you mix up things a bit - the document you posted is only shows DB 605DB engine type. 605DB was never supposed to run at more than 1,8ata, so its not "restiction", limits are shown what is always meant for this engine type. Kurfürst - DB 601, 603, 605 datasheets - DB 605 DB/DC

Do you have also this document table for DC? wwiiaircraftperformance only shows DB datacard. I do not trust this site so much when it deals with German maschine, in past it has been pointed out of bias and selective. This case only show rating for an engine that everyone know was not ever think of for higher rate than 1,8ata, so why show it? I think it is misleading practice.

It was 605 DC that was supposed to run at 1,98ata. Kurfürst - DB 601, 603, 605 datasheets - DB 605 DB/DC
Now, the first document says 1,98ata was cleared for Troops and order was to set engine for it, this was in or before Januar 1945, ie. 1944, but this was without sufficent test process. So order of 1,98ata was delayed until II/JG 11 combat test group did testing. In March 1945 this 1,98ata boost was ordered for four wings of fighter regiments 27 and 53 to be used. I suppose planes already converted in II/JG 11 also kept it use. Granted this did not change in war plan, even Me 262 did not at all. I doubt anything would. Also I do not believe it had many importance. 1,98 add about 200 HP, from paper it seems some like 10-15 km/h speed at below full pressure heights, a bit more climb rate but G-10 and K-4 were already fast and excellent climber, as good or better than anything else there.. so I do not get why so many people get so emotional over this subject or try to deny.

Some units would have received this instruction for higher boost after Bf109 production had ceased and they were receiving old G-6s from training units.

Which units you speak of, that instructed 1,98ata boost increase, but received only G-6? G-10 and K-4 were main type in 1945 in inventory, produced in very large numbers (4000+ produced of these two in war so I very DOUBT shortage of new type..). G-6 was no longer in front service.. They already replace even G-14 and older model on production line (production Me 109 btw still run April 1945).

 

[vanir]

I've been looking into this over the last few days. Ther is no evidence proving operational use of 1.98 ata by any combat units. The one unit that we know experimented with the higher boost pressure, II./JG 11, was disbanded during the first few days of April,probably at the same time as several units of Luftflotte 6 (to create a reserve!) and some from Luftflotte Reich and Luftwaffe Command West.

'Interner Aktenvermerk Nr. 6642' from Daimler-Benz dated 17 Jan 1945 reports on a meeting held 10 January 1945 at OKL, Berlin. All 4 DB 605 DC engines supplied to Rechlin from DB-Genshagen failed (pistons, piston rods, supercharger). It states that 1.98 ata boost pressure is not to be allowed for combat units.

'Die Sondernotleistung DC (1,98 ata Ladedruck) für die Truppe nicht freigegeben.'

It is inconceivable that combat units would have been using it earlier.
Niederschrift Nr 6717 from Damiler-Benz, dated 19 January 1945, states that DB 605 D engines from Kassel are delivered at 1.80 ata boost
None of the units flying K-4s for 'Bodenplatte' were operating 1.98 ata boost.

Ratsel you can fly your simulations with what ever engine configurations you choose but in the real world they didn't exist.

Cheers
Steve

This mirrors a point I was trying to bring up to Ratsel several times without much success, I think you put it better than me. As a footnote however there is a thread over at LEMB which examined this very question at length, using primary sources, and the best they could come up with was two particular airfields that were getting delivered only C3, no B4 at all was going to those two airfields in March 45, and yet they operated both G-10 and G-14/AS. It was surmised that these aircraft were probably operating 1.8ata on C3 without need of MW50 use (ie. had 605DB and 605ASB engines), but probably used it anyway (it will extend the climb setting duration if you throttle back after switching it on, kinda handy for a fast intercept).

 

[stona]

I did confess that I haven't translated the entire document,my conversational german isn't up to it. I'll get it done eventually.

Nr.6730 refers to a meeting held on 20 Jan 1945.

I'd love to see that table for the DC engine! I'm aware that 1.8 ata isn't a restriction as they were already running those motors at that boost pressure.

II.JG/11 may have continued running some aircraft at 1.98 ata boost after March 20 1945 for the two weeks until they were disbanded on or about the 4th April 1945. That's assuming that they hadn't blown all the higher boosted motors by then,like the ones tested at Rechlin.

As a quick example no less an authority than Prien gives the example of II./JG53 (one of only a handful of units now left on 'Defence of the Reich') receiving old G-6s in his JG53 history.

"On 23 April the unit had four Bf 109 G-6s, on 24 April this figure had already risen to 32 Bf 109 G-6s, of which none where servicable".

I think III.JG/27 may have been one of the other units receiving obsolete aircraft but that's from an unreferenced note on my HD....don't quote me!
You'll note that this is in April and Bf109 production had finished. Luftflotte 6's war diary mentions the cessation of production on 3 April 1945 so it stopped sometime prior to that date. Peter Schmoll in his 'Nest of Eagles' gives the last production date loosely as March 1945. I'd suggest late March.

Cheers
Steve

 

[Milosh]

vanir, do you the link to that LEMB thread?

 

[vanir]

Milosh I'll have to hunt for it and I'm about to go to bed. You might be able to get it with a site search worded something like "Me-109K on C3 fuel" or "Me-109K with DB-605DC motor"
I'll try hunting for it if I get time before work tomorrow.

 

[kettbo]

Hello George
my info is
for Bf 109G-6, 1,42ata is the Start- und Notleistung, ie Take-off and Emergency power, allowed for 1 or 3 minutes, depending on the manual you looked, 1495hp,
530km/h at SL 640km/h (398mph) at 6.600m. With MW50, if this was installed later on, ie in practice G-14, 570km/h at SL

109G-10/R6 bad weather fighter with autopilot with Combat and climb power (30min) 500km/h ? at SL, my copy is so dark that I'm not sure on the last digit, 655km/h at 9000m. Max speed with Sonder 562km/h at sea level, 690km/h (429mph) at 7500m

K-4 (max 1.8ata / 1800hp)
combat and climb power (30min /1275hp at SL) 515km/h at sea level, 670km/h at 9.000m
Max with Sonder 580km/h at SL, 710km/h (441mph) at 7.500m.

Juha

Thanks Juha!
I'll be making a spreadsheet so any other data posted here will help. I'll post the product for general review

 

[Juha]

Hello George
I noticed one embarrassing typo in my message, the right 1,42ata Start- und Notleistung for DB 605A-1, the engine of 109G-6, is 1475hp, I'll also correct the original mesage.

And the czech writer of an article on Bf 109G-10 had read the SL speed in the GL/C-E 2 document same way as I, so it is 500km/h with Combat and climb power, but the max speed with Combat and Climb power is 653km/h at 9.000m .

Juha

 

[Juha]

Hello George
in the tread More complete english translation of Major Kozhemyako - Topic

in the message by Buzzsaw- on Tue October 04 2005, 09:54 you can find good info on tactics used over Eastern Front by 109G-2 and Yak-1b pilots and also speeds used, not exactly late war but in 43 and early 44, but very informative analyze on tactics used by LW and VVS fighter pilots at that time by a VVS combat veteran.

Juha

 

[jim]

Hello George
in the tread More complete english translation of Major Kozhemyako - Topic

in the message by Buzzsaw- on Tue October 04 2005, 09:54 you can find good info on tactics used over Eastern Front by 109G-2 and Yak-1b pilots and also speeds used, not exactly late war but in 43 and early 44, but very informative analyze on tactics used by LW and VVS fighter pilots at that time by a VVS combat veteran.

Juha

His conclusions about German tactics, do not agree with german pilots memories.

 

[Milosh]

His conclusions about German tactics, do not agree with german pilots memories.

What would these differences be?

 

[riacrato]

Interesting interview and very detailed. Off topic: Is it proven to be real? I'm only asking because the man's memory is astonishing! Is it true the Me 262 flew propaganda missions like that?

 

[Juha]

Hello
cannot say nothing on 262 case, haven't read that part yet. On tactics, at least Finns noticed that many times VVS used Yaks as the close escort of Il-2s and La-5F(N)s were lurking higher up as a top cover. And what I remember on the behaviour of British close escort, it was very similar to that of Soviet according to Kozhemyako's interview. And results were much the same, close escort, if it saw the Germans in time, had same problems with the high speed attacks of the Germans.

Juha

 

[drgondog]

The P-51B/C/D had excellent roll rate at high speed because of internal balancing of the ailerons in which pressure from the deflected aileron is channeled to a belows that relieves loads. The thick wing of the P-51 had room to fit this equipment as well as to be made quite stiff. The FW 190 had a high roll rate becuase of the stiffness of the two spar wing, the thinness of the wing tips and the use of friese ailerons which scooped air from the opposit side to reduce force and prevent adverse yaw. Again note that the Me 109F + had Friese ailerons unlike the Me 109E, it also had differential ailerons in which upper deflection is about twice as great as downward deflection.

Another factor which hurts roll rate is inertia coupling: an aircraft does not fly along its principal axis; hence when it rolls the weight at the nose and tail tend to be centrifuged outwards. This was not well understood during WW2 but caused a great many problems with early jets (super sabre). I suspect the lower roll rate of the FW 190D over the FW 190A was caused by this; hence hydraulic boost was brought in.

Interesting theory - and the 109D certainly added mass moment arm for nose, but no additional weight for tail - just extension of moment arm due to the plug. Any analytical evidence to support the theory? With the same waing as the Anton, your thesis is interesting

The Me 109 may have had wings that compressed such that the ailerons stiffened but in its favour was a short span, stiff wings that did not twist and short body with the weight close to the center of lift and with a long tail momment arm; all factors which help roll rate.

We also know that late model Me 109s outdived P-51D's We 'know this' how?

I really would like to see a chart and measurments or at least a simulation.

I would also.. the highest terminal dive velocity for the P-51D that I am aware of was .85M. What do you have for the best version of the 109?

 

[drgondog]

"Aeroelasticity" is a new one to me, but, if the Spitfire wing was so weak, how did 2nd TAF manage to hang a couple of 250lb. bombs under the wings of the IX, XVI XIV? As far as I remember the 109 could only carry a single bomb under the fuselage. From the Mk.I, inspections were introduced to check for wrinkling of wings after heavy manouevring; only if the leading edge D box showed signs, or the rest of the wing had wrinkles above 1/10", was the wing changed.

Edgar - Aeroelasticity was a very poorly understood science in WWII. But it is about the fact that even stiff torque boxes defelct under load and the deflections create interesting aerodynamic and structural effects.

A Spit manuevering with 250 pound bombs is a completely different beast from a Spit in level flight.

The Spit I through IX had the same basic wing/aileron combination. At 400 mph the spit ailerons were about 35% effective raech control reversal at approximately 550 TAS. The P-47 at 400mph was about 65% effective and the 51 about 70% - which is wht the P-51B/C/D out rolled bot (and the Fw 190) ~ 400 mph. The wing twisted under the eccentric aileron loads for all of them, but least for the 51,

.

The Spit out turned the 51 and the 109 simply because the Wing Loading was less, and the wing CL was about the same.. Other factors for sure at high AoA but they favored the Spit over the 109. It got more complicated with the Spit/51 comparison at medium to high speed because the 51 was superior aerodynamically and form drag for the 51 was less than the Spit at high AoA (statement w/o facts yet to support it)

 

[GregP]

The only WWII aircraft that could possibly suffer from inertia coupling would be the Bachem Natter, and I don't believe it ever flew long enough to get into the phenomenon.

Others might suffer from aeroelasticity, such as rolling to the opposite direction when applying full aileron at very high speed (the F-86 did that), but not from intertia coupling. To get to intertial coupling, you would need a very fuselage-heavy aircraft with small, highly-loaded wings. I believe inertia coupling was first seen in the X-1A and X-2. It got yeager in the X-1A, and he spin out of control ... but he recovered. It killed Mel Apt in the X-2.

The Do 335 qualifies in the heavily-loaded fuselage category, but not in the small, highly-loaded wing category.

Opinion, Drgondog?

 

[drgondog]

The only WWII aircraft that could possibly suffer from inertia coupling would be the Bachem Natter, and I don't believe it ever flew long enough to get into the phenomenon.

Others might suffer from aeroelasticity, such as rolling to the opposite direction when applying full aileron at very high speed (the F-86 did that), but not from intertia coupling. To get to intertial coupling, you would need a very fuselage-heavy aircraft with small, highly-loaded wings. I believe inertia coupling was first seen in the X-1A and X-2. It got yeager in the X-1A, and he spin out of control ... but he recovered. It killed Mel Apt in the X-2.

The Do 335 qualifies in the heavily-loaded fuselage category, but not in the small, highly-loaded wing category.

Opinion, Drgondog?

Greg - I agree except for blank statement "only the Natter". I just don't know enough about all the WWII designs but in general I agree but have added this definition to illustrate that an Fw 190D may have been a threshold airframe.. That is why I didn't dispute Siegfried per se - just curious because the cases of inertial coupling that I looked at in grad school were airframes as you described them with far higher roll rates than the Fw 190 or 190D, such as a Pitts.


Inertia Coupling, a form of instability, only becomes prominent with aircraft having high roll rates and when successive rolling occurs. The result is an undesirable increasing pitching as rolling continues. The cause usually arises from the mass distribution of an aircraft whereby mass fore and aft of the cg is flung centrifugally away from the axis of roll. It may occur with an aerobatic piston engined aircraft having a heavy tractor engine in front preventing the performance of a clean rolling motion and causing the roll axis to wave around in a circular or eliptical motion.