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

Gotta' respond to davparir's post on page 9.

You have a good comparison of the Me 109 and P-51 numbers but are missing or perhaps glossing over some vital points. You may very well have missed nothing.

1. The P-51 retained its maneuverability well into the 400+ mph range and is not tiring to fly there relative to the Me 109. The Me 109 was a slow-to-medium-speed dogfighter and had no trim for the rudder and aileron. It was easy to fly at 180 - 280 mph. Faster than that and the maneuverability was pretty much lost and the pilot was very tired fron having to continually push the rudder. The cockpit was small, particularly in width, and most pilots could not apply more than about 40 pounds of side force, severely limiting roll performance.

2. The P-51 had good visibility everywhere. The me 109 had good visibility forward and to the side, but almost none forward and left or right and almost none to the rear.

Of the above, number 1 is most important. If the P-51 kept the speed up, it was the master of any Me 109. If it allowed itself to get slow, the Me 109 could ba a real problem. Ergo, most P-51 pilots who speak at our museum events say they never got slow in Europe and if the opponetns were slow, then the P-51 did boom and zoom tactics until the defenders were gone or shot down or they themselves had to leave for home.

Sure, some guys got slow and some Me 109 pilots were probably stronger than others and might get a decent roll performance at 380 mph.

By and large, the P-51 was much better than the Me 109 above 350 mph and could yaw, pitch, and roll better than the Me 109 at high speeds. In today's skies, it still IS better when flown fast, according to the people who fly them today.

Naturally, I assume there is some disagreement, but the Me 109's performance at high speed is pretty well documenrted to be sluggish at best, and high speed was generally used for escape or to get into position to attack. That makes things look a bit different, at least to me and to the Mustang pilots I know.

What do YOU think Jimh? You are a Mustang pilot. Tell us about the high-speed behavior of the P-51.

@ davparlr, I assume you used P-51B data as there was no P-51D till August 44? Was it with shackles, what boost level (100/150 etc?).
I think you are using data for a 100/150 octane 75 inches mercury (2.5 ata) P-51 without bomb shackles. The engine produced 1860hp in this
configuration.

Also the G-14 data incorporates the 2 x 30mm gondola guns for anti bomber use whose weight effects climb rate significantly and cuts down speed 1-2% (3-8mph)
(Of the top of my head you would be getting around 422mph not 416 with the ASM version).

The Me 109 series didn't really catch up till October 44 with the entry into service of the Me 109K4 and a month latter the Me 109G10 when the airframes were cleaned up (eg retractable tail wheel like the P-51) and a another new generation of engines came in eg DCM, ASCM etc.

As far as greater speed at sea level: the 1.8 ata to 1.98 ata boost gave a very decent 378mph SL with the new thin blade prop using C3 fuel which tests at 96/130. The effect of superior allied fuel should not be underestimated in providing part of the P-51 superiority: 100/130 fuel was really 104/130+

Note the allies were effectively already using thin blade props, they compromised climb rate ie low speed traction.

Now a note about the P-51H, it never flew at 487mph, this was an engineering estimate, it was a 475mph aircraft with a half fuel load, the engineering estimate being brochure talk that presumably did not adequately incorporate compressibility effects. Even in this configuration (90 inches) the A/C used water injection and 100/150 fuel which puts the experimental SL 413mph in doubt to me. This site suggests 401 mph was possible using 90 inches (3 ata of 28psi) in the clean configuration:
P-51H Performance Test

As far as future speed increases of the Me 109K series a boost pressure to 2.2 ata is conceivable; this might be accomplished by using a 100/145 fuel (10% increase in performance number), or simply a spark plug upgrade or an increased RPM limit. Using a cube root law 1.1^0.33 we could expect a 3% speed increase from 378mph to 390mph for a 10% increase in boost. The scimitar tip prop, which was an area of heavy German research, would probably give another 2% on top of that.

A 2.3ata -2.4 ata rating for the DB605 is not inconceivable to my mind with the correct fuel.

To improve their fuel the Germans needed to get alkylation plants on line, they had started planning these in 1940 but only 1 was ready by 1943 as such plants take years to design, build and commission. They were also experimenting with aniline and the kind of additives the allies used in 100/150 fuel.

Aerodynamically the Me 109 was out of date compared to the P-51. The Me 309, which flew belatedly due to lackadaisical support in June 1942 turned out to have problems with production numbers of its DB603 engine and despite its impressive speed of 466mph was less maneuverable. It probably needed another 6 months of work (bigger wing I expect). This aircraft had a laminar flow wing and an 80% increase in range over the Me 109 but it would have been too much of a production disruption with the Me 262 on the way.

The Ta 152C series and FW 190D13 represents the future of piston engined combat aircraft for the Luftwaffe. These had impressive new engines on the way such as Jumo 213EB or J.

The FW 190 could also have wing fuel tanks added which would have added considerably to range while the Ta 152 had them already.

kettbo said:

Just for reference here, Spitfires provided early escort for the USAAC bombers. These were relieved by P-47 (and P-38 when available). Then these were relieved by P-51 for the furthest penetrations...

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What you are describing is the relay system. P-47's were relieved by P-38's which were relieved by P-51's for the final penetration. Fighters typically cruised 100 mph faster than bombers. To stay in contact with bombers the fighters had to fly a zigzag course. This used up fuel. A relieving group of fighters could fly in on a straight course and conserve fuel.

For this to work there had to be no errors in navigation or timing.

Ratsel. It's DB-605ASC not ASCM. Just ASC. There is no such thing as ASCM or DCM. It is just DC. All ASC and DC motors already use MW50, there is no need to specify a type that does or doesn't, all of them do without further modification or any changes. So look up Mtt docs, it's just ASC and DC. Same with ASB and DB.

You only need to specify if an A-1 or AS is using MW50, because you have to use C3. It's about what fuel card to put on the airframe, not about MW50. AM and ASM means C3. DC and ASC means C3. A-1, AS mean B4 and DB and ASB use either with or without MW50 without further modification or any changes.


Next thing, you've spent time around LEMB, there's been quite a thread over there discussing the DC motor and they managed to pin it down to one airfield using G-14 and G-10 aircraft (JG301) which were only being delivered C3 fuel, no B4 fuel was delivered to that airfield, yet they operated G-10.
But 1.98ata had not been cleared, and the DB motor settings of 1.8ata is fine with C3 fuel instead of B4, you don't even have to use MW50 for 1.8ata on C3.

So it is most likely in fact that no DC or ASC motor was used in the war, the RLM wanted all Daimler and Jumo inlines to run on B4 I've 1944 documents specifying it. They didn't want them to run on C3, they wanted them to produce around 2000PS on B4, and would rather chop output slightly than use C3. Farben Industries specifies this in wartime documents.

What is most likely is that particular airfield of JG301 was getting C3-only for their FW Antons, no B4 due to fuel shortages and simply put C3 in their G-10s with DB motor settings, 1.8ata.
That is most likely.
The 605DC/ASC were not cleared for 1.98ata until Mar45 or thereabouts anyway.


But that is likelihoods, and remain conjecture yes. But this is what you hold onto when trying on the other side of the argument. Straws man. No kidding, just straws.
You want to say what, 1.98ata was cleared in Mar45 and instamageously every second G-10 or K-4 in the Luftwaffe had it distributed and in service that afternoon?
And the C3-only DC/ASC motor really needs to be fitted at the factory, I explored the possibility a DB/ASB could be retuned in the field, but it has to be done during engine assembly I found out.

So how are those engines going to be fitted before Mtt/RLM clears them for airworthiness? That would be Mar45. How many could you get in the air in a month under heavy bombing?
In that thread at LEMB there were precious few airfields even capable of getting new 109s and C3 fuel in the same place at the same time, how are you going to account for that?

Need to also remember that when big raids were put into effect, it generally took some time to form up. Typically about 1-2 hours. From there there was the flight to target....assume something like berlin, with a range to target of about 700miles. US bomber formations when in large groups cruised at about 180-200mph.. thats at least 4 hours flying time to the target, and another 2-3 hours to get out of Dodge.

Germans were watching allied skies by radar from the moment of the first take off. the trick was to try and work out where the bombers were aiming for, but with up to 9 hours in the air, and about 7 hours to prepare (on the way home) ther was plenty of time for CAP to be re-positioned and ready to attack in concentrated waves Outnumbering the LR escorts by 5 or 6 to one at selected points was easy for the germans, provided everything went to plan. Trouble was it often didnt. most german pilots had not received any blind flying training and were so badly trained that had to play follow the leader to get where they wanted to go. Allies were doing their best to confuse the controllers and used every means they could think of to try and fool the germans. It often worked. Lastly, the range of the Me109s, and FWs were a limiting factor that often preventing achievement of the theoretical concentrations.

Germans had the numerical advatages, at least in theory, but a number of factors conspired to prevent them from always achieving that advantage.

But in my opinion the overwhelming reason for the one sided loss rates for german fighters to US fighters was not to do with numbers, or the equipment....a me 109 is a fighter that i would welcome into the allied inventory anytime. the overwhelming problem was th falling quality of Luftwaffe pilots. That coupled with poor strategic control of the fighters, made Allied victory a certainty....in part it was handed to them by German mistakes and skills failures. They were outgeneralled, outflown, outengineered and outwitted

As far as I can tell there was the ASB and DB engine which could be switched to C3 and MW50 1.98 ata.

Siegfried said:

As far as I can tell there was the ASB and DB engine which could be switched to C3 and MW50 1.98 ata.

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Different piston/rod kit mate. Higher static compression. Different valve timing, have to change the cams. Spark curve is different, got to change the magneto gears. Boost regulator has to have its firewall limits reset. Plugs changed. Fuel card has to be changed. Engine block has to be restamped.

vanir said:

Next thing, you've spent time around LEMB, there's been quite a thread over there discussing the DC motor and they managed to pin it down to one airfield using G-14 and G-10 aircraft (JG301) which were only being delivered C3 fuel, no B4 fuel was delivered to that airfield, yet they operated G-10.
But 1.98ata had not been cleared, and the DB motor settings of 1.8ata is fine with C3 fuel instead of B4, you don't even have to use MW50 for 1.8ata on C3.

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Over kurfurst seite has some allied docs showing C-3 found in G-10 G-14. do not say unit number though... Could this be JG 301 unit? Kurfürst - OKL, GdJ-Grp. Qu-, Br. B. Nr. 1561/45 g.Kdos. von 20. März 1945.

So it is most likely in fact that no DC or ASC motor was used in the war, the RLM wanted all Daimler and Jumo inlines to run on B4 I've 1944 documents specifying it. They didn't want them to run on C3, they wanted them to produce around 2000PS on B4, and would rather chop output slightly than use C3. Farben Industries specifies this in wartime documents.

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Are you sure no DC ASC? These mentioned many times in documents, in fact, DC and DB are same engine. Convertible, like Siegfried knows. Everywhere I read they are changable with screwdriver..

What is most likely is that particular airfield of JG301 was getting C3-only for their FW Antons, no B4 due to fuel shortages and simply put C3 in their G-10s with DB motor settings, 1.8ata.That is most likely. The 605DC/ASC were not cleared for 1.98ata until Mar45 or thereabouts anyway. But that is likelihoods, and remain conjecture yes. But this is what you hold onto when trying on the other side of the argument. Straws man. No kidding, just straws.
You want to say what, 1.98ata was cleared in Mar45 and instamageously every second G-10 or K-4 in the Luftwaffe had it distributed and in service that afternoon?
And the C3-only DC/ASC motor really needs to be fitted at the factory, I explored the possibility a DB/ASB could be retuned in the field, but it has to be done during engine assembly I found out. So how are those engines going to be fitted before Mtt/RLM clears them for airworthiness? That would be Mar45. How many could you get in the air in a month under heavy bombing?
In that thread at LEMB there were precious few airfields even capable of getting new 109s and C3 fuel in the same place at the same time, how are you going to account for that?

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I say it is probable explanation. Likelyhood depends on weight of evidence... is there serious evidence showing no DC engine? So what was cleared 1,98ata was for? What was it banned for? Over kurfurst there is German document from Januar 1945. It says Daimler Benz forwarded DC engines at front.. why are aircraft labeled with C3 fuel if they are with B4 engine?

Sorry I am somewhat skeptical of this. But I do not know thread.

Regarding original thread. I say late P-51 and Bf 109 are equal planes overall. Different strenghts. 109 is an interceptor, P-51 is an escort. Former has better performance, not all regards (for example - speed is equal on P-51), but overall slightly better. 109 is not so usuful as escort in its original configuration, because fuel size and weapons is designed for interceptor duty; it is possible to do escort missions; P-51 is not very usuful as intercept in its original configuration, because fuel size and weapons is designed for escort duty; it is possible to do intercept of course.

It is always balance of capacity. If not, designers would have come up with "perfect" fighter already, no need for so many designs..

DC/ASC is indeed same engine as DB/ASB (and only difference between DB and ASB is the blower), and the technical term for the changes is "mechanical tuning" but the changes I mentioned (or ones very much like them) are required.
Static compression on the DC is 8.5/8.3 compared to 7.5/7.3 on the DB, the trick used to allow higher blower pressures is valve timing to bring dynamic compression back under control, overall the effect is higher flow rates and that means more power. It's a harmonics thing though, unique setup working best for B4 fuel is different to the one working best for C3 fuel, they burn very differently.
IG Farben left behind some docs about fuels usd by Luftwaffe fighters, details these points, discusses how much trouble it was developing the 605D-series all-new combustion chambers.

Siegfried said:

@ davparlr, I assume you used P-51B data as there was no P-51D till August 44? Was it with shackles, what boost level (100/150 etc?).
I think you are using data for a 100/150 octane 75 inches mercury (2.5 ata) P-51 without bomb shackles. The engine produced 1860hp in this
configuration.

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I am not sure what post you are addressing here. For the post that compares P-51D data to the Bf-109G-14 AM and ASM, I used data from a P-51D at 67" Hg boost corrected for assumed similar improvements shown to the P-51B in the upgraded fuel test at 75" Hg. I did not use the P-51B data per se.

Also the G-14 data incorporates the 2 x 30mm gondola guns for anti bomber use whose weight effects climb rate significantly and cuts down speed 1-2% (3-8mph)
(Of the top of my head you would be getting around 422mph not 416 with the ASM version).

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This is certainly a weakness in any comparison. USAAF test are pretty good at defining conditions of test such a weight, clean-ups, and rack configurations. German test do not seem as thorough with data although some might but in German, which is Greek to me. For the data I posted on the Bf-109G-14, I do not know if racks were installed or even if they are removable. I assumed they weren't installed. Rack affect on top speed on the P-51B were estimated on the chart at about 10 mph at SL.

The Me 109 series didn't really catch up till October 44 with the entry into service of the Me 109K4 and a month latter the Me 109G10 when the airframes were cleaned up (eg retractable tail wheel like the P-51) and a another new generation of engines came in eg DCM, ASCM etc.

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These plane were quite formidable and could outperform the P-51B/D in climb and airspeed over the entire envelop. I think they were quite limited in endurance. Germany needed them in quantity in January, '44, not October, '44.

As far as greater speed at sea level: the 1.8 ata to 1.98 ata boost gave a very decent 378mph SL with the new thin blade prop using C3 fuel which tests at 96/130. The effect of superior allied fuel should not be underestimated in providing part of the P-51 superiority: 100/130 fuel was really 104/130+

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Fuel was certainly a technological advantage for the Allies.

Now a note about the P-51H, it never flew at 487mph, this was an engineering estimate, it was a 475mph aircraft with a half fuel load, the engineering estimate being brochure talk that presumably did not adequately incorporate compressibility effects. Even in this configuration (90 inches) the A/C used water injection and 100/150 fuel which puts the experimental SL 413mph in doubt to me. This site suggests 401 mph was possible using 90 inches (3 ata of 28psi) in the clean configuration:

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I would agree with all of this. The tests referenced were run with racks so that could account for the variation with speed. Also, engineering estimates at Focke Wulf was reported at 4% error so if North American had a similar error this also could account for the difference.

As far as future speed increases of the Me 109K series a boost pressure to 2.2 ata is conceivable; this might be accomplished by using a 100/145 fuel (10% increase in performance number), or simply a spark plug upgrade or an increased RPM limit. Using a cube root law 1.1^0.33 we could expect a 3% speed increase from 378mph to 390mph for a 10% increase in boost. The scimitar tip prop, which was an area of heavy German research, would probably give another 2% on top of that.

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Certainly higher octane fuel would have increased performance of German engines. I do tend to discount possible engine upgrades since so many engines did not perform as expected. What you listed seems reasonable. However, I suspect that, like the forward swept wing of some proposed jets, the scimitar prop was probably beyond the material capability of the day. I also think the Bf-109 airframe was aerodynamically limited.

A 2.3ata -2.4 ata rating for the DB605 is not inconceivable to my mind with the correct fuel.

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Seems very high. I do know that the R2800 was run somewhere around 3500 horsepower for quite awhile, but I don't know what boost that was. I certainly think there would be a reliability risk with this. But I don't know enough to challenge comment.

The Ta 152C series and FW 190D13 represents the future of piston engined combat aircraft for the Luftwaffe. These had impressive new engines on the way such as Jumo 213EB or J.

The FW 190 could also have wing fuel tanks added which would have added considerably to range while the Ta 152 had them already.

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The EB was reasonable, the J more problematic, and the Allies were already running engines at these levels and more (the P-47M/N R2800 was flat rated at 2800 hp up to 33k). In any event, both Axis and Allied planes powered by these types of engines would quickly become obsolete as the new jets started to dominate the airspace.

Tante Ju said:

Regarding original thread. I say late P-51 and Bf 109 are equal planes overall. Different strenghts. 109 is an interceptor, P-51 is an escort. Former has better performance, not all regards (for example - speed is equal on P-51), but overall slightly better. 109 is not so usuful as escort in its original configuration, because fuel size and weapons is designed for interceptor duty; it is possible to do escort missions; P-51 is not very usuful as intercept in its original configuration, because fuel size and weapons is designed for escort duty; it is possible to do intercept of course.

It is always balance of capacity. If not, designers would have come up with "perfect" fighter already, no need for so many designs..

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Please read post #131 and #138. From the advent of the P-51B up until the introduction of the Bf-109G-10 and K, the P51 had significant airspeed advantage over the Bf-109.

The 109 was equal to the P-51 in top speed in its later versions, and was superior in rate of climb in some parts of the envelope, but was vastly inferior at high speed as a fighting aircrfaft.

It was very good at 180 - 290 mph, but was completely outclassed as a figher at anything over 300 mph. It had poor visibility from the cockpit frward and left or right, was very short ranged, had no rudder or aileron trim, and was short of skilled pilots, fuel, and propellers late in the war.

The 450 mph range in an Me 109 was not for fighting, it was for other reasons of survivial or attack position. At that speed it was not going to attack, but would flee or move to another position fron which to attack at slower speed.

Lt Hans-Ulrich Flade flew Me-109G-14, G-10 and K-4 with JG27 in 1945. He says firstly the final versions of each had about the same performance. He said secondly his flight never had any problem escaping Mustangs in a climb. His job was to break up enemy escort formations (Mustangs mostly in 45) for the interceptors (Me-410/109G/Fw190A mixed interceptor groups and jets). He would dive as a pair or four out fo the sun on the Mustangs, break up their formation and then zoom clear, change course, find another group. He said the problem was if you got into a dogfight, the escorts were too numerous and you'd eventually be clawed to the ground no matter how you flew.

Feb44 British Ministry comparative test report of a captured Me-109G-2 versus the new Hawker Tempest V (I think the only other Gustav they had at the time was a heavy G-6/U2 and the G-2 was quicker). Compiled and paraphrased (eg. metric conversion) notes of interest:
-At heights above 5000 metres the speed advantage of the Tempest rapidly diminishes. Below 5000 metres the Tempest V is 65-80km/h faster.
-At speeds up to 350IAS (565km/h indicated) the Me-109G-2 handles easily as well as the Tempest through all manoeuvres, "there is nothing to choose between them" are the exact words of the report. Only above 565km/h IAS is the Tempest superior in manoeuvrability if the pilot changes bank and direction frequently. I think those are very interesting words.
-The Tempest V has a slightly superior turning circle to the Me-109G.
-The initial climb rates of the Me-109G is superior to the Tempest V at all heights but this advantage is not so pronounced under 1500 metres.
-In sustained climb the Tempest V is slightly superior to the Me-109G only if it begins the climb at speeds above 400km/h.

Tempest V entered service in April 1944. It's counterpart would be the Me 109G6AM or Me 109G6ASM a few months latter the Me 109G14AS and Me 109G14A. Engine power went up from about 1470hp to about 1750hp due to the 1.7 ata boost rating in both sets of aircraft. Tempest still faster though down low.

"Then there was the American Mustangs that we both dreaded and anticipated meeting. We knew that they were a much better aircraft than ours; newer and faster, and with a great range....."

the interview with Erich Hartmann

bobbysocks said:

"Then there was the American Mustangs that we both dreaded and anticipated meeting. We knew that they were a much better aircraft than ours; newer and faster, and with a great range....."

the interview with Erich Hartmann

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Erich Hartmann met P51 in june 44 over Rumania flying Bf 109 G6 (no boost)
By the way , i have no any reference by Hartmann speaking of Mw 50 boost even later in the war.

Of course, Erich Hartmann was the best fighhter pilot ... or rather most successful fighhter pilot, in the history of the world, all wars together.

I think that qualifies as a combat of not-nearly-equivalently skilled pilots, if ever one did.

It would seem to be over claiming by 4 by Hartmann on the June 24 1944 date.

"I was on the June 24th mission and only 1 P-51 was lost on the Ploesti mission. The other loss was on an Air Sea Rescue escort mission. Welch was hit by light flak in the Pescara, Italy area and crashed into the sea.
For the Ploesti mission, 46 Mustangs took off, 7 were early returns, 39 Mustangs rendezvoused with the B-24s at 0920 hours, 38 Mustangs left bombers at 1021 hours. 38 P-51s down at base at 1530 hours. Claims were
1 Me-109 destroyed 2 FW-190s destroyed 1 IAR 80 Probably destroyed
2 IAR 80 destroyed 2 ME-109s Probably destroyed

I believe the FW-190s were actually IAR 80s

Cordially, Art Fiedler"

jim said:

Erich Hartmann met P51 in june 44 over Rumania flying Bf 109 G6 (no boost)
By the way , i have no any reference by Hartmann speaking of Mw 50 boost even later in the war.

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He was issued the latest G-14 model in June as a replacement (his G-6 was the same one used in Crimea and getting clapped out), but the build quality was so bad he refused it. He used a simple rank procedure to requisition a low-hour G-6 airframe from the Ergänzungsgruppe. I believe it was field converted to "G-14 standard" which many good G-6 were rather than scrapped, and from about Nov43 builds the 605A/AS engine doesn't need to be changed for an MW50 conversion. You can tell field conversions because the G-14 serials are stamped right over the top of the old G-6 ones with a hammer if at all (sometimes G-6 plating is kept), the fuel card is changed and they don't have the new instrument panel, instead an MW50 guage is bolted to the old G-6 panel (landing gear often painted red if MW50 fitted, as C3 required in older A/AS motor). In süd-ostreich you don't need the new radios so that part is easy.

So Hartmann's "G-6" of July 44 was fairly likely to be, for all intents and purposes a particularly well built G-14 with an old G-6 instrument panel. Some of these field conversions didn't have MW50 installed, there were many "partial conversions to G-14 standard" so there is no real way to tell the exact specification of Hartmann's aircraft, but it is reasonable to assert general differences between the G-14 and G-6 during 1944 were largely superfluous, their potential specifications could be interchangeable.

After 1944 Hartmann is attributed with 2x G-6, 2x G-14 and 1x G-10 from memory, although the G-10 is often reported as a K-4 and one G-6 and one G-14 are probably the same airframe.

Hartmann flew a G-10, even had his Black Tulip on the nose ( I can post a pic that proves it 100% if need be). Its well known on the aircrafts Hartmann flew. As far as Hartmanns comments on the P-51, probably true, but he did shoot down a few, and He was never shot down by a P-51.