Bf-109 vs P-40

JoeB said:

e between a 'trust me' source and pointing to a book or other record.

What's needed to verify a calculation (I'm also an engineer by training) is to show that it's predictions agree with full scale results over the whole range of applications in which you claim it's authoritative. It's not just to present 'the math' and effectively claim everyone who can't disprove that particular math must believe the calculation's accuracy. All engineering calculations are models of reality. Whether they model reality sufficiently for all the cases in which you use them is shown by agreement to full scale results.

This is coincident with my own opinions on this subjet by theory and experience. well said Joe!

Again I think a difference that creeps in here is that some people's aim is really to create a virtual reality for sim games which is well defined and predictable, and not wildly out of whack with the real world of WWII fighter a/c. Their goal is not really to fully explore the reality of WWII fighter a/c, with all its uncertainties and anomalies, which may just not be suited to a single answer. And sometimes that difference in goal shows.

Joe

Click to expand...

aero is complicated. I didn't spend 6 years in the academic side of the business and conclude that it was straightforward. It is a science and an Art... both structural and fluid mechanichs of a real airframe.

HoHun said:

Hi Les,

Well, here it is as a parting gift ...

Regards,

Henning (HoHun)

Click to expand...

I hope you're not actually leaving, Henning, as I enjoyed your contributions.

Some comments from observers on the P40 during WW2: " The P40 was behind the times when introduced and never caught up. But it was the best available fighter at the time."
" The P40 could be very effective, and if well flown could even best an ME109 at low altitude."
" Stalin to Roosevelt, October 7, 1942: " It should be borne in mind that the Kittihawk planes do not stand the fight against present German pursuits."
" The primary disadvantages of the P40s were lack of range and altitude capability."
" No matter what we did we just couldn't make an ME109 out of a P40."
" The Germans in North Africa found that the P40 turned quickly and well against the ME109 while the latter was faster and climbed better. The German aircraft could intially dive more quickly as well,but in a long dive a P40 could catch a ME109."

JoeB and others - I apologize if my post was redundant. I was trying to contribute after slogging through the previous posts. I neither on one side or the other but as I happened to have that book, I thought some passages would be a good addition. Sorry, Joe if it seemed like beating a dead horse.

I like HoHuns graphs.
I don't always agree with them, I don't always interpret them the same, but I like them, and I appreciate how much work must go into making them. I know I can't make them.

The graphs I would like to see would be a comparison of the Spitfire Mk IX and XIV (18 lbs boost)to the 109G6 and K4 (1.45 ata).

I suspect those plottings would generate some discussion.

Whenever I read about the P-40 a common theme seems to appear. It seems that it was a plane that could get good results if flown by someone who really knew how to fly it. It the hands of an average, inexperienced pilot it wouldn't be able to compete with a Me-109 on an even level.

Watanbe said:

Whenever I read about the P-40 a common theme seems to appear. It seems that it was a plane that could get good results if flown by someone who really knew how to fly it. It the hands of an average, inexperienced pilot it wouldn't be able to compete with a Me-109 on an even level.

Click to expand...

I think that's the message many of us were sending here....

Probably should of read the whole topic then

Watanbe said:

Probably should of read the whole topic then

Click to expand...

No worries

Hello
According to Soviet tests time to make 360deg turn at 1000m: Bf 109F-4 20,5 sec, Bf 109G-2/R6 (with 20mm underwing gun gondols) 23sec, Bf 109G-2 21sec.
Curtiss P-40C 18sec, P-40E 19,2 sec.

Juha

Interesting.

Juha said:

Hello
According to Soviet tests time to make 360deg turn at 1000m: Bf 109F-4 20,5 sec, Bf 109G-2/R6 (with 20mm underwing gun gondols) 23sec, Bf 109G-2 21sec.
Curtiss P-40C 18sec, P-40E 19,2 sec.

Juha

Click to expand...

Very interesting!


Do you have a source for that Juha?

Hello Flyboyj
easest way probably still is Table of ftrs 1943
but I have seen the same figures also in Soviet/Russian literature.

Juha

Thats an interesting table, thanks for sharing that Juha! I can see why the Soviets liked the Bell P-39 too! Its too bad there are no roll rate comparisons in that. I think that would be the deciding factor in conjunction with the 360 turn rate. If for example the Me109F rolls faster and then can begin its turn a little sooner it may be a tie. But Im not sure the 109 will out roll the P-40 either, at least down at low altitudes. So if the P-40 could out roll and out turn the Messerschmitt, that would certainly somewhat counter the better speed and climb of the Messerschmitt. And again, the P-39 with a little more speed than the P-40 is even better, though it still would not climb like the Me109.

I think that the P40 was a useful plane but when it British service it lacked a Merlin powerplant which I think held it back.

The Allison engines were not particularly good from what I have read elsewhere, and so the plane was almost doomed from the start with its powerplant.

A lot of WWII planes seemed to get stuck at a certain point, and the only way to move on was to make a brand-new plane !

It seems that if a plane is fundamentally flawed like the Helldiver or the Defiant or the Short Sterling even, you are never going to get much improvement even with endless tweaks.


Comments please ! (and welcomed)

Cromwell said:

I think that the P40 was a useful plane but when it British service it lacked a Merlin powerplant which I think held it back.

The Allison engines were not particularly good from what I have read elsewhere, and so the plane was almost doomed from the start with its powerplant.

A lot of WWII planes seemed to get stuck at a certain point, and the only way to move on was to make a brand-new plane !

It seems that if a plane is fundamentally flawed like the Helldiver or the Defiant or the Short Sterling even, you are never going to get much improvement even with endless tweaks.


Comments please ! (and welcomed)

Click to expand...

Actually some mis statements. The Allison was a good engine, it depended on the airframe and the configuration of installation. As far as Merlin powered P-40s, I believe those powered by the allison were actually faster.

Cromwell said:

I think that the P40 was a useful plane but when it British service it lacked a Merlin powerplant which I think held it back.

The Allison engines were not particularly good from what I have read elsewhere, and so the plane was almost doomed from the start with its powerplant.

It seems that if a plane is fundamentally flawed like the Helldiver or the Defiant or the Short Stirling even, you are never going to get much improvement even with endless tweaks

Click to expand...

There was nothing wrong with the V-1710 within the context of its performance spec; it possessed 1,040hp vs 1,030hp of its contemporary version of the Merlin. It took 10 years to develop vs 4 years for the Merlin but people tend to conveniently forget that the Merlin's development was funded by the government whereas the V-1710's development was only company funded.

A V-1710 with the bugs eventually ironed out (for 'eventually' read company funded - above) proved to be a very reliable engine in service at the altitudes it was rated for and Allison can take part-share over the blame for the absence of a supercharging arrangement, the USAAC can take the other part; prior to 1938 the USAAC had committed to the use of engines with turbochargers and Allison, to make production easier, manufactured all the V-1710 units in a common standard form (thus enabling all marks of engine to be produced by one, single line). The only way to fit a two-stage supercharger now was as a separate unit and external to the engine.
The USAAC obviously weren't happy about this but Allison enlisted Curtiss to help persuade the USAAC to use the V-1710 with its integral mechanical supercharger. Once accepted, it gave the required performance at the requiremented altitudes and no further development of the supercharger took place.

A turbocharged version of the V-1710 was fitted to Lockheed's P-38 and in the Allison's -F5R and -F5L versions they were as powerful as equivalent two-speed, two-stage Merlins above 25,000ft and even more powerful at higher altitudes than that.

I can't speak for the Helldiver but the Defiant was as much a victim of British conservatism and lack of imagination, as technical shortfall. It was clearly never going to compete with a Bf109 with a lumping great four-gun turret strapped to its back but with a little vision and a few modifications (radial engine, armour tub for the pilot, up-gunned armament) what a superb battlefield close-support platform it might have made against troop concentrations and soft-skinned vehicles; rather than being confined to head-on passes, it could have orbited its intended target with a moving turret constantly hosing it down - bet the Soviets would've bought it... the world's first AC-designated gunship?

Thank you chaps for your robust and informative responses. A number of thoughts spring to mind :

Merlin Obsession
---------------------

Firstly, I do think that Whitehall was 'Merlin Obsessed' to the point that it actually partly-sabotaged the development of other engines like the Napier Sabre.

For example, Napier were forced, by the MOD, to give copies of their engineering drawings to Rolls-Royce - imagine that ! No wonder they struggled.


Merlin P40 - Why ?
----------------------


Taking note of your comments - why did they make a Merlin version of the P40 ? (Warhawk, Kittyhawk etc) ?

If the Allison was satisfactory, why produce a Merlin powered variant, especially with Packard at full stretch producing Merlins for the P51 Mustang


Defiant - Naval Version ?
-----------------------------

I agree that the Defiant was totally mis-used and abandoned too easily IMHO. After all, it was actually a *good* plane to fly - well balanced and quite powerful.

With its wide 'cart and robust construction I have often thought that a Naval version of the Defiant could have worked with the following adjustments

1. Replace the top-heavy dustbin turret with a twin gun mount (twin Lewis or Vickers)

2. Give the pilot 2 or 4 forward firing Brownings or even some 20mm Cannon

3. Fit racks for Bombs / Depth Charges or 3" Rockets on Zero-zero launchers (as also fired by the venerable if vulnerable Swordfish).

4. Hook - obviously

Lets face it, it could not have been any worse than the Barracuda or Helldiver


Note. part of the problem with the Helldiver was that the USN insisted on a Short fuselage to get it down standard elevators.

That is why it was always directionally unstable.


Matthew

Hello Mike
P-40C and F outrolled Bf 109F easily at 10.000ft, P-39D-1 outrolled Bf 109F at speeds over 330mph IAS at 10.000ft but at slower speed 109F was better. On later P-39s i have no data, P-63A was better than P-40F.

Juha