1941: the best airframe for a single engined fighter

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Hello Dave
Sorry to say, but on 21 May 44, there was no USAAF raids around that area, no Hartmann' P-51 claims and no 15th AF Mustang losses, so it is no use to make any conclusions on that story.

Juha
 
The japanese proved what range could do for an air force. For the defender it would be devastating, and by the latter half of 1941, the germans were almost exclusively on the defensive on the western front. That had implications as suggested in Gallands book.

By giving the british range AND the initiative, the LW would be conceding an awful lot. A lot more than what just one JG could achieve. Instead of 2 Gp and the 18 or so squadrons of FC that were committed to the campaign (at the start....it gradually increased as time went by) being restricted to attacks up to about 120 miles from the british coast, attacks with escort could have been mounted virtually anywhere in the Reich. at miniimum that means that one of the two JGs based on the Coast would have to decentralise, and even then, full coverage could not be provided. Bombers attacking by day, untroubled by any defensive fighters are a significant menace. The RAF by March '42 already had the ability to put 1000 bombers over the target by night. And in '42 those raids were starting to bite deep, culminating in Hamburg a year later, easily the worst raid prior to 1945. And these raids were at night, with the constant fear of NJGs and the inherent navigational issues affecting accuracy. how much more devastating if the raids were unintercepted, and conducted by day. It alters the equation of the strategic offensive enormously. In fact there is every reason to support the notion that LW would be forced to pull back 80-90% of their available fighters for reich defences in '42, exactly as they were forced to do in '44 when the US began its deep penetration escorted raids.

Whilst I agree that engine development does affect the realization of the airframes full potential, arguing that an aircraft with similar performance as the Spit V but with massive range could not provide effective escort is silly in my opinion. The German types of 1941-2 were generally superior to the SpitV, but not by that much as to say Merlin 45 equipped Mustang could not provide effective escort. Dont know about the allison, because i dont know about the engine really. But i am confident that if the Mustang of 1942 had been equipped with the earlier version of the merlin, it still would have been quite capable as a long range escort. If necessary expedients could have been adopted like reducing the armament, or the amount of armour,which could have lifted or retained adequate performance, though i doubt such expedients would be necessary. Once you get to that point the LW is in a world of hurt.
 
With a similar engine to a P-40 or Spitfire, the Mustang was anywhere from 20 to 40 mph faster at any given altitude. That speaks greatly to the aerodynamic efficiency of the aircraft and presents a major advantage for the Mustang.

For example, the V-1710 P-40E would do about 310-320 mph at sea level. The P-51 with the same power would do 345-355 mph.

A Merlin 61 powered Spitfire Mk IX would do 330 mph at sea level, 4040408 mph at 25,500 feet. A V-1650-3 powered P-51B would do 350-355 mph at sea level and 440-445 mph at 25,000 feet.

A V-1650-1 powered P-40F would do 360-365 mph at 18,000-21,000 ft. With roughly the same power, the (slightly more aerodynamic) Allison powered P-51s were getting to 395-405 mph at about 17,000 ft in 1942.

That puts a V-1650-1 powered P-51 firmly into the 400 mph + category aircraft above 20,000 ft. And that's a huge advantage.

The P-51 was not only a fast aircraft, but a very good pilots aircraft. It was light on the controls, accurate in response and had very few bad habits. It possessed better manoeuvrability (roll, rate of pitch, turning circle) than the slightly lighter P-40. The Mustang might lose out to a Spitfire in overall manoeuvrability, but its better than anything else the RAF and USAAF could field.

A US review of the British experience with the P-51/P-51A after 18 months of combat found:

"It has been found that the Mustang is faster than the ME-109 and the FW-190, and that 4000 to 8000 is a good altitude at which to catch the enemy. At sea level, the Mustang can run away from any enemy aircraft they have encountered to date. The pilots are schooled to run rather than fight because their main objective is the destruction of ground targets, not to fight enemy aircraft. They are instructed in the use of flaps in combat to reduce their turning radius (which with flaps is shorter than the ME-109 or FW-190). At least one FW-190 has been made to spin in through the use of a small amount of flap by the Mustang when engaged in a turning contest at low altitude; the FW-190 tried to tighten his turn to keep the Mustang in his sights after the pilot had dropped his flaps slightly but spun out of the turn."

AND

"Actual combat has proven that the aircraft can run away from anything the Germans have. It's only inferior points are that it can't climb as well as the ME-109 and FW-190 and that at the slower speeds of close combat it loses effectiveness of aileron control and therefore has a poor rate of roll – but its turning radius with a slight amount of flap is shorter than either of the German aircraft."


A hypothetical Merlin 45/V-1650-1 (1240 hp) powered P-51 would probably have a speed, roll rate (at high speed), high speed controllability and dive advantage over a Spitfire V and (under 25000 ft) against a 109F2/4, but a disadvantage in rate of climb, turning circle and low speed acceleration and roll.

Against a 190A-2/3/4, it would have a turn advantage and maybe speed advantage at higher altitudes. It would lose out in performance under 20,000 ft, rate of acceleration, rate of roll and rate of climb, particularly at lower altitudes.
 
Jabberwocky,

I would like to pint out that the V-1650-1 wasn't a Merlin 45, but rather a Merlin 20 series (equivalent to a 23 IIRC).

A P-51 fitted with a Merlin 45 would most likely be slower than a P-51A below the rated altitude of the V-1710 (about 12,000ft IIRC), and probably not be any faster until near the Merlin 45's rated altitude (c. 18,000ft), but above that it woul ddefinitely be faster.

The 45 was a single speed-single stage supercharged engine, the V-1650-1 a 2 speed single stage engine.
 
Jabberwocky said:
A Merlin 61 powered Spitfire Mk IX would do 330 mph at sea level, 4040408 mph at 25,500 feet. A V-1650-3 powered P-51B would do 350-355 mph at sea level and 440-445 mph at 25,000 feet.
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I have seen perfomance numbers for the Spitfire IX as much as 417mph but, WOW, 4040408mph!

Time must slow down for the pilot!

 
tomo pauk said:
As an airframe in combat service, think it's hard to argue against the Fw-190. The prototypes in 1941 are all another ball game, the P-51 looks like a winner.
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This. As an airframe in service the Fw 190 was performing well and had plenty of development potential, being able to take up heavier engines, heavy armament, more equipment and more fuel while remaining relatively clean and having enough of a margin not to deteriorate handling too much.

The prototype P-51 was exceptionally clean and well designed without taking too many risks (e. g. evaporative cooling) or being too complex to build economically. As such it was the apex of piston engine airframe development. I don't see why it shouldn't be able to take up an engine in the class of the Griffon or DB603, it just wasn't necessary.

The Typhoon should also get a mention of some kind. While I think the airframe was not as sound as the above two from the beginning, it evolved into the very good Tempest and Fury.
Also, weren't Yak 3 prototypes around in 1941? Would also make for an interesting choice.
 
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Depending on which airplane it was mounted in the V-1650-1 could be a 28 or a 29 or a 31 or a 33 or a 38.
 

How do you want to have initiative against the Kammhuber Line and do such raids unintercepted?
The Kammhuber Line with it's search radar is fact since 1940! And to my knowledge radar is functioning at day and night!

The only effect would be a deeper defending system of the JG's against the P51 and the Nightfighters of the LW, from 1941/42, would be the bomber interceptor of the day with the FW 190A and the BF 109F as P51 interceptor. Also all short comings of the Kammhuber Line at night wouldn't exist at day, so the german search radar could work at it's full potential.

Or do you want to tell us the RAF had the possibility at 1941/42 to do 500 or 1000 bomber raids at day and night?

A Merlin 45 powered P51 would not have the performance of a Spitfire MkV because it would be 2000kg heavier (full loaded) then a Spit MK V.
So I don't see how the P51 (with Merlin 45) will be an efffective escort fighter.
Both the FW 190A and the Bf 109F were at 390 to 397 mph combat high speed at 1941/42, so I don't see any significant advantage of the P51 at that timeline, but it would be much slower in climb performance against both german counterparts. And also as reallife has shown against the Spitfire MK V turning performance isn't that important compare to speed, climb and role rate.

Sorry but this argumentation had nothing to do with the military, performance and most important the technology facts from 1941/42.
It wouldn't be that easy with an "underperforming" P51 (Merlin45), compare to the Bf 109F and FW 190A, to destroy the LW.
To me, it is more the opposite, because the LW could play all it's good parts much more easily at day light and as I said I have great doubts that a P51 Merlin 45 powered was in the same performance leage as a Spitfire Mk V except perhaps speed.
 
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Originally Posted by pinsog
"I repeat P51 was excellent, top escort fighter (along late p38s) but during all its carrer i could see better dogfight/air superiority airframes,
Many german pilots had this opinion too"

I didn't post that. I replied to it in an earlier thread. I disagree with the above statement. I believe the Mustang was a better airframe.
 
jim said:
a) MW50 was nothing special, 150 octane fuel was special
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That is why I used 67" in comparing the B to the Bf-109F. 67" did not need 150 octane. With this capability the P-51B was 50 mph faster than the Bf-109F with similar climb. 150 octane allowed 75" and provided overpowering performance.
b) Ki84 why was not fast? 2000hp in a relatively small airframe
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It was fast but not as fast as the P-51D
C) P51A accelarated very slowly to its top speed. It is reported in this forum
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Yes but its top speed was 20 mph faster than the Bf-109 could go. A better comparison would be who was faster to 325 mph from 300 mph. I suspect the P-51 would win this since the Bf-109 was running out of available hp where the P-51 was not.
d)F4 is 41/42 machine
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P-51 was indeed only becoming available and had not flown a mission.
e) G56 was 685-700 km/h machine
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Impressive machine, a bit slower than the P-51B but looks to be formidable. I never found the 700 km/h number.
 
That is why I used 67" in comparing the B to the Bf-109F. 67" did not need 150 octane. With this capability the P-51B was 50 mph faster than the Bf-109F with similar climb. 150 octane allowed 75" and provided overpowering performance.
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Which source do you have for this claim? From testflights the Bf 109F4 was 660 km/h (emergency output 5 min.)fast and now you want to tell me that the P51B was 740 km/h fast?
Kurfürst - Mtt. AG. Datenblatt, Me 109 G - 1. Ausführung

What source do you have for the equal climb performance?

Yes but its top speed was 20 mph faster than the Bf-109 could go. A better comparison would be who was faster to 325 mph from 300 mph. I suspect the P-51 would win this since the Bf-109 was running out of available hp where the P-51 was not.
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Any comparation or source for this claims especially for the P51 A

I haven't seen so much tendential claims at this forum at a long time!

Edit:
The P51 A had a speed advantage of 20 mph at SL till 10000ft (5 mph)!
From 10000ft to 15000ft the speed is equal and after 15000ft the Bf 109F is much faster.

At 20000ft 410 mph (Bf 109F4) ,373 mph (P51 A)
At 25000ft 400 mph /Bf 109F4), 357 mph (P51 A)
 
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Fuel = endurance. This is useful for more than just range.
 
imho the P-51 it's not the right reply to problem. sure is a clean and new (the production started 7 months late of that of Friedrich) design with high speed but it's also a heavy plane. whatever engine you put in it in 1941 you get a fast fighter (relatively to engine power) but with bad climb (and accelaration) performance. So for 1941 i got to choice a lighter plane as best airframe for a common cheap fighters (my candidates, Friedrich, C.202) , if you need a long range idk if Mustang is best of a Zero for that mission.
 
Vincenzo said:
imho the P-51 it's not the right reply to problem.......
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Which problem?

The original Mustang had the space to hold four 20mm guns with a decent amount of ammo.

It had the ability to carry a pair of 500lb bombs (not one) before you get to the Merlin versions.

It did have ability to hold more powerful engines without a major degradation in flying qualities.

It may not have been the best in any one category ( or two) but what other airframe could do as well in as MANY catagories?
 
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The problem is the definition!

I'm inclined to agree that the P51 was the best airframe at 1941 with a close matchup of the FW 190 (all what you have above mentioned, you could also write about the FW 190).

But we have here more then one discussion about the P51 and I realy doubt, that a P51 at 1941 with the engines of this timeline (Merlin 45) could be a successful escort fighter against the Bf 109F and FW 190A. The airframe of the P51 was getting better with each more powerful engine step, but the engines at 1941/42 were not powerful enough for the escort fighter missions.
 
short the problem is the definition, the title of thread, the tomo ask.
you can put 4 20mm, the bombs also in a Hurricane... the 51 is a large plane it's obvious that can load many weapons.
the trouble is that fighter first mission is shoot down enemy fighters and 51 is not so good in this in 41, whatever 41 engine you put in it.
the 190 also is a heavy plane and with '41 engine has trouble
 
Give the Mustang the same engine as the Hurricane II and see what happens. The Merlin 45 was the 2nd best Merlin at the time. The Spitfire never got the 'best' 1941 Merlin because they were still trying to keep the Hurricane in the game.

A P-51A with 9.60 supercharger gears could get 1150hp at 17,500ft with RAM. it could do 408mph at 17,500ft, at 25,000ft is was supposed to do 395mph using 836hp.
I wonder what it could do using a Merlin XX giving 1120hp at 18,500ft without ram? 1120hp at 20,500ft? 1000hp at 25,000ft?

Climb at 20,000ft was supposed to be 1980fpm using 910hp.

I wonder what it would have been using 1050-1075hp at the same height (less RAM while climbing) from the Merlin XX?

The Merlin XX gives nothing away at low altitude like the Merlin 45 would.

Tomo asked what was the best all around fighter airframe, not what was the best point defense interceptor or best for fighter to fighter combat. If you need another airframe to perform the bomber intercept mission then the claim to best "all around"is already fading fast.
 
To make numbers even more suitable for comparison:
- V-1710-81 (for P-51A) makes 1125 HP at 14600 ft, no ram; ram effect elevates the FTH for almost 3000 ft (to 17500); SR6 covered the high speeds power available for climb.
- V-1650-1 (for P-40F*) makes 1120 at 18500 ft, no ram. Lets elevate the (second gear) FTH some 3000 ft, due to ram effect - the thinner air at 21500 enables the plane to make 415 mph there, 405 at 25000 ft. Hope it makes sense.

The weight of the plane might be an issue for a defender that need to climb at 20-30000 ft, but not for the plane making escort job (taking off from UK and flying to the Continent). He is already at good altitude when above Belgium. And P-51 is no snail under 20000 ft either.

* basically a late 1940 vintage engine
 
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