Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained)

[MIflyer]

I see, so you theoretically could have a P-40F right after Pearl Harbor. Disregard my previous post then

First P-40F to get into actual combat service that I know of was for Operation Torch. So it took about 11 months from first flight to combat deployment.

By the way, interesting thing was that whille all the P-40's at PH in Dec 41 were P-40B's, in the PI they were mostly P-40'E's with only one squadron of B's. I wonder if they sent the B's back to HI or if only one squadron of B's made it to the PI before E models came.

 

[Greg Boeser]

But didn't you hear? the Japanese and Germans, when it was clear they were going to lose the war, systematically destroyed all loss records and wrote new ones to hide their true losses from the victorious Allies. I read it in a book once.

 

[Greg Boeser]

PI was getting the most modern stuff because the War Dept. believed that it was the most likely target for Japanese aggression.

57th FG received P-40Fs in June 1942. Took off from USS Ranger on 19 July, 1942, bound for Africa. Arrived in Palestine for operational training by August 1st. First combat sorties 9 August 1942. First combat loss 14 August, 1942 near El Alamein.

 

[BiffF15]

Interesting shot of what appears to be AVG planes getting overhaul or re-assembly. Of note is the far left tail as it looks like a K or M model. Anyone have info on which versions the AVG actually flew?

 

[fubar57]

BiffF15 PM sent

 

[Shortround6]

Are you sure it was a book and not online?

 

[Shortround6]

I see, so you theoretically could have a P-40F right after Pearl Harbor. Disregard my previous post then

Yes, No, maybe????

Packard Built 45 Merlins in 1941, 26 of them in December.
The British were supposed to get 2/3 of production and the US getting 1/3.

How this was divvied up I have no idea, every 3rd engine was labeled US. First 60 got to England/Canada and the next 30 go to the US and then repeat? batches of 200 and 100?

AHT says that the prototype P-40F flew June 30th 1941 with a British engine. First P-40D had been delivered in May 1941.
AHT says that the first production P-40F was delivered Jan 3rd 1942.
May of 1942 sees P-40K versions start to be delivered.
July 1st 1942 sees the P-40Fs of the 57th fighter group loaded onto the Carrier Ranger for shipment to Africa. It takes about the whole month of July to transport them for Rhode Island to the Gold coast (they are flown off about 100 miles from shore) and then to cross Africa and up to the middle east and their base in Palestine. It takes until Aug 31st for the 57 fighter group to operate as a single unit, individual squadrons had trained with British units on combat operations.

So it is not wither or not you could A P-40F but if you could get enough to equipe a squadron or group, get them trained and get them to a combat theater. A Squadron of P-40Fs in Buffalo New York in January of 1942 is hardly going to affect any combat operation.

 

[Greg Boeser]

Definitely a book. Probably about the Flying Tigers.

 

[ThomasP]

re: P-40E/F/N speeds and ROC

Airframe________P-40E_______________P-40F_______________P-40N
Flying Weight___ 8680________________8980________________7400 lbs*

Vmax@Alt______340@12,500_________ 354@20,400_________ 378 mph@10,500 ft
Power_________1150________________ 1120________________1480 BHP*
_______________Military______________ Military______________WEP

ROCmax______ 1840________________ 2050________________ 2680 ft/sec
Power_________1000________________ 1120________________ 1125 BHP*
_______________Normal______________Normal______________ Military

The above is from a RAAF document. They used all 3 models, and I think at the same time for a brief period?

*Note:
1. Note that the P-40N is at extremely light flying weight, and WEP is used for Vmax and Military is used for the ROCmax, as opposed to Military and Normal for the P-4E&F. Military power for the P-40N is 1125 BHP at 15,000 ft (no RAM) so if we compare apples to apples the Vmax with Military would be ~346 mph for the same plane at 10,500 ft, or ~370 at 16-17,000 ft with RAM. The V-1710-81 engine in the P-40N has the same 1000 BHP Normal power as for the V-1710-39 in the P-40E, so the ROCmax would be about 2280 ft/sec for the 7400 lb weight.

2. If WEP (1440 BHP) for the V-1650-1 in the P-40F is used for speed the Vmax would be would be ~365 mph at 15-16,000 ft.
If Military power (1240 BHP) for the V-1650-1 in the P-40F is used for for climb the ROCmax would be ~2360 ft/min.

Both #1 and #2 assume that the aircraft are in the same flying condition as for the RAAF data.

 

[GregP]

Reference post #220 above. The weights you have are not normal flying weights from what I find. Some are maximum takeoff weights and some I can't find at all. Don't know where you got the rates of climb, but I certainly have better numbers from credible places, and they are all better than yours. The P-40N is NOT at extremely light weight. 7,400 lbs was the normal flying weight. It was 6,000 lbs empty and 8,850 lbs maximum takeoff weight. Nobody flew combat at maximum takeoff weight. That was for ferry flights or perhaps as a bomber, it certainly wasn't for fighter combat!

We have and fly a P-40N and it very handily exceeds 3,000 feet per minute with full fuel and two people in it. The P-40N-1-CU had 4 guns. Later N's got heavier along with 6 guns.

 

[ThomasP]

Hey GregP,

Sorry, I should have posted these but I did not find them right away. As I said, the values not under Note are from RAAF test data.

Also, I should have said "extremely light flying weight in comparison to the E&F models".

 

[tyrodtom]

I raced circle track 17 years.
During a lot of that time one of my sponsors was a guy who took videos of every race. I got free videos.

I'd watch every bit of my race, slowed it down and watched it slow motion.

Sometimes incidents on video wasn't how I remembered them, and that was under the stress of just racing.

 

[GregP]

I got my numbers in the Excel post above (post 201) here:

P-40 Performance Tests

and other places on the web. Seems like some discrepancies. But, I have never seen a WWII fighter with a max climb rate of less than 2,000 fpm before, and still don't think I have. Most of the less than 2,000 fpm climb rates are at normal power, not rated power.

 

[ThomasP]

Hey GregP,

P-40N (actually a P-40K) No. 42-9987 test says basically the same as I have listed above, ie Vmax at WEP of 378 mph at 10,550 ft and at Military 371 mph at 17,300 ft (with RAM). ROCmax of 2680 ft/sec at 1105 BHP at 15,000 ft (Military), but adds the WEP ROCmax of 3720 ft/min. The TOGW as tested was 7403 lbs. (I do not have the detailed w&l numbers for the different variants of the P-40N, but with normal fuel (120 USgal) and ammo for 4x.50 cal TOGW should be about 7600 lbs+.)

P-40F report No. 41-13601 test says a bit different from what the RAAF report gives, ie Vmax of 364.5 mph at 19,270 ft at Military (1105 BHP). The ROCmax of 2210 ft/min at Normal (1240 BHP) is also a bit different, but the weight "as tested" is listed as 8450 lbs, which could account for the ~9 mph difference in Vmax and the 150 ft/sec difference in ROC.

P-40E No. 40-384 (w/o belly tank) test says basically the same as I have listed above for Vmax at Military (1150 BHP), ie 342 mph at 11,400 ft. The ROCmax is listed as 2400 ft/min at ~Military (ie 1120 BHP as opposed to 1000 BHP which is the actual Normal rating). The increased power used and the significantly lighter weight of 8011 lbs "as tested" easily accounts for the difference in ROC.

I am not sure where any significant numerical performance disagreement comes from?

 

[P-39 Expert]

Merlin P-40F performance was almost exactly the same as contemporary P-39D/F/K/L when the same power settings are used.

 

[Schweik]

P-39 wasn't doing so hot at 20,000 ft

 

[fubar57]

 

[Schweik]

Both P-40F/L and P-40N had both lightweight 'interceptor' or more accurately 'vs. lots of fighters' configurations, general purpose configurations, and 'heavy' fighter-bomber configurations. The weight (not counting bombs) could vary by > 800 lbs. That is the difference in speed, rate of climb etc. It causes a lot of confusion. It's why top speed for a P-40N ranges from ~ 340 to ~380 mph in various tests, and P-40F similarly from ~350 mph to 370.

P-40F/L still had a better / higher performance ceiling (by about 4,000 ft) than any configuration of P-40N.

Note the P-40L is basically just a P-40F with the same stuff stripped out in the factory that they were already removing from P-40F in the field. In some cases they put a lot of it back (like the two wing guns and forward wing fuel tank) and made it back into a P-40F.

This is the test I referred to which showed 370 mph for P-40F or L (Kittyhawk II)

 

[Schweik]

As for the P-39, which I know is a zombie horse (and who isn't sick of zombies these days) - it was a flawed design which also had significant potential. It was basically hard to learn to fly and hard to learn to optimize in terms of maintenance and field modifications (esp. vis a vis thing like the balance with the big gun and ammunition), which is something that all WW2 fighters contended with to some extent or another. The Russians made it work, partly because their Theater was ideal (where low altitude, short range fighters were the norm) it suited their fighting style (maintaining speed, shooting from short range) they did a long workup on it before throwing it into the breach (very different from Allied units in the Pacific), and perhaps most important of all, Russian pilots who flew it had already cut their teeth (and been through a brutal winnowing process) flying in combat with planes like I-16s, MiG 3s, LaGG-3s. If you lived through a year fighting the Luftwaffe with one of those, a P-39 was like a dream, both in terms of flight characteristics and performance. I.e. the I-16 etc. were all known to be 'twitchy' and easy to spin, and with difficult spin recovery traits. So if you were a pretty good pilot in one of those a P-39 would theoretically not be so much of a challenge, and then you can take advantage of the nice rate of climb, speed, streamlining (which helps keep speed up) armament etc.

The P-39 also had working radios, and I also believe it may have flown better in cooler or cold weather. They certainly had less problems winterizing them than they did with Hurricanes, Spitfires or P-40s.

It is and will always be a mystery, how the Russians made it work (and unlike some of our Luftwaffe fans, I believe they did) while nobody else could, but no more of a mystery than how the Finns did so well with the F2A compared to the USMC, and I think it boils down to many of the same factors.

 

[P-39 Expert]

P-39 wasn't doing so hot at 20,000 ft

See my homemade graph below with figures from wwiiaircraftperformance.org (thanks) for the P-39K vs P-40F. P-39K was an early model with the -63 engine with 8.8 supercharger gears. Not the uprated -85 engine with the 9.6 gears.

In speed the P-39K and P-40F (blue dots) were absolutely equal at 19275ft with the P-39K being much faster below that altitude.

In climb the P-39K was superior at 3000rpm (red dots) but the P-40F (blue dots) was using best climb 2850rpm, at 3000rpm would have been about the same as P-39K.