P-40 Warhawk/Kittyhawk (1 Viewer)

Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules

Something you'll have to explain to me - why is it that I keep seeing comments about the P-40's weight?....or rather, overweight.

I think if you averaged out the weight for all the different models of P-40 that existed, I bet you'd find the plane generally found itself around 8500-10000 lbs.
Does this make the P-51, which was like 12500 lbs. by the time the "D" model came around, obese?
If so, why does that fact never seem to come up whenever the 51 is mentioned?
Comparitively, the P-40 seems like a lightweight and yet I see comments written all the time about the plane being overweight.





Elvis

A 51 at 12,500 pounds is one that just took off with two 160 gallon ferry tanks or two 1000 pound bombs, and a full internal load of 270+ gallons of fuel and 1860 rounds of 50 cal... and 200 pounds of pilot.

Yes, that would be obese for air to air combat - but the 51 would still be faster than the P-40K (and light) at 25,000 feet.

The empty airframe weight of both ships were close - the Mustang had the heavier engine and far more internal fuel.
 
Elvis, switching from the other thread and discussing a P40 outclimbing a Spit, Bob Johnson in his book, "Thunderbolt" said the early Jug could not stay with a Spit in a steady climb. His tactics in a mock dogfight with a Spit were, with the Spit on his tail, to start rolling one way and then the other, as the Spit did not roll as well as the Jug. Once he had the Spit out of firing position, he would dive(the Spit could not stay with him in a dive) until reaching a very high speed and then zoom climb as the Spit could not zoom climb like a Jug, until far enough above where he could hammerhead stall and drop down on the Spit still laboring to get to his altitude. The P40 rolled well(better than the Jug) and dived well. Perhaps the pilot you quoted meant that he could outclimb a Spit in a zoom climb.

I just came to the exact same conclusion in the Brewster Buffalo thread. :)

drgondog said:
Yes, that would be obese for air to air combat - but the 51 would still be faster than the P-40K (and light) at 25,000 feet.

The empty airframe weight of both ships were close - the Mustang had the heavier engine and far more internal fuel.

Thank you ever so much for pointing that out. I do get annoyed with people (often Spitfire fans) who deride the P-51 as a "pig" because of it's high loaded weight. One must remember that a P-51's "combat" weight- having reached the target, and burned up a little less then half of it's fuel- was much. much lighter. And if you want to compare the P-51 to a dedicated, short-legged interceptor like the Spitfire or the 109, then only factor in 30 minutes worth of fuel for the P-51, since a Mustang being used in that role wouldn't be prepped with more then was needed, to improve performance.
 
Back to the P 40 weight question. Lets compare it too a Hurricane IIb. Both planes of similar dimensions and size with the same engine.

Tare weights H IIb 5,467 lbs P 40f 6,482

Combat weights H IIb 7,255 P40f 8,979 (P 40 carries more fuel 174 gals to 94)

top speed HIIb 342 mph 24,000 ft, P40f 354 mph 20,400ft

Climb rate

H IIb 2,950 ft/min P40f 2,370 ft/min


I guess you could presume that the drag co efficient is fairly close, with a slight adv to the P40f ? But look at the neg affect weight has on climb rate.

Slaterat
 
To me, as an armchair fighter pilot, climb means at least two things. One is how long it takes to climb to where the fight is or is going to be. The P40 really labored to get from the ground up to say 25000 feet. That hampered it in the interceptor role. Two is the ability to climb away from an opponent in ACM. The P40, if it started with an altitude advantage, could make a diving gunnery run, and then zoom climb to regain altitude advantage. If a P40 found itself with no altitude advantage against an A6M or BF109, it was in trouble as far as offensive action was concerned.
 
I'll second the problems with interception in a P-40 (try climbing to chase bombers in that tub sometime in any game you might want to name,) but a lack of altitude is not as much a problem versus a Zero, whereas it's problematic versus a 109. Zero pilots loved to exploit their good climb rate, so sooner or later the Zero was going to dominate the altitude advantage- which could be negated by the P-40s higher top speed. Simply extend away and let the Zero hang there all it wants.

You can't do that with a 109, however, and the 109's superior power makes it dominant in the vertical as well. Victory there would really rely on the P-40 managing to force a scissors or turn and burn fight, where it excels.
 
The power loadings tell the tale. At 10000 feet the power loading of the P40F at 8678 lbs GW was 7.11 and at 20000 feet was 8.15. The corresponding for the P51D at 10176 lbs GW were 6.78 and 7.48. The P40 at all altitudes had more weight per HP available and was not nearly as clean so drag not only slowed it down but hampered it's climb significantly.
Ah, maybe that's it.
Yeah, without some decent SC'ing, that plane loses a lot, and fast, as it goes up.
So maybe the "overweight" comments were that it seemed a bit "pudgy", due to the lack of power at altitude.
Ok, thanks, that's most likely it.

As for the P-40 vs. Spit comment, hey, like I said before, I don't know what else to tell you.
I ran the video and watched it myself, just before I wrote that, because I couldn't exactly remember how those comments went.

If you like, maybe you could get a copy of the video and watch it for youself, then you can tell me what he meant.

The video is called "Kittyhawk" and is about a restoration project by the late Col Paye.

Upon the restored plane's maiden flight at Scone in NSW, a bunch of WWII Aussie pilots were invited to watch the proceedings, Bobby Gibbs being one of them.

The host of the show interviewed Gibbs while sitting in an (that?) airplane and was asked to comment on some of the performance pluses of the P-40.
Some of those comments are what I posted in that other thread.

Lastly, I finally drug my butt over to the "mustangsmustangs" website and yeah, you're right. 12500 was a little on the "portly" side for a D varient 51.
Sorry, was working off the top of my head (as I usually do) and that's how I remembered it.




Elvis
 
A couple more musings about the P-40 / Spit comparison...

According to Chuck Hawks
A Spit Mk.IIA of 1940 had a "best" climb of 3,025 ft/min at 12,800 ft.
It could achieve 10,000 ft. in 3.4 min and 20,000 ft. in 7 min.

According to Joe Baugher
"The first flight of a P-40 (Ser No 39-156) was on April 4, 1940. Maximum speed was 357 mph at 15,000 feet, service ceiling was 32,750 feet, and initial climb rate was 3080 feet per minute. An altitude of 15,000 feet could reached in 5.2 minutes. The length of the P-40 was 31 feet 8 3/4 inches, which became standard for all early models. Weights were 5376 pounds empty, 6787 pounds gross, and 7215 pounds maximum."

Now, if you look back at Chuck Hawk's comments of a Spit of similar vintage and average out those "time-to-altitude" figures, do you know what you end up with?

15000 ft. in 5.2 min. :eek:

Exactly the same figure as Joe Baugher states for the first P-40 (incidentaly, that works out to 2884.6153 ft./min.)



Elvis
 
Hello Elvis,

Typically the climb rate of an aircraft improves slightly as the aircraft goes from sea level to 3000 to 5000 feet and then decreases as the altitude increases. Thus your identical average climb rates to different altitudes doesn't mean the aircraft climb rates are comparable.

This is just a personal opinion, but JoeB is about as reliable as it gets as far as facts and research. I don't believe I can say the same about your other source.

BTW, for the general discussion, consider that early Allison engine Mustangs had essentially the same engine as installed in contemporary P-40s and were about 30-40 mph faster. That says a lot for aerodynamics. I wonder what would have happened if the P-46 had been developed alongside the P-51.

- Ivan.
 
A couple more musings about the P-40 / Spit comparison...

According to Chuck Hawks
A Spit Mk.IIA of 1940 had a "best" climb of 3,025 ft/min at 12,800 ft.
It could achieve 10,000 ft. in 3.4 min and 20,000 ft. in 7 min.

According to Joe Baugher
"The first flight of a P-40 (Ser No 39-156) was on April 4, 1940. Maximum speed was 357 mph at 15,000 feet, service ceiling was 32,750 feet, and initial climb rate was 3080 feet per minute. An altitude of 15,000 feet could reached in 5.2 minutes. The length of the P-40 was 31 feet 8 3/4 inches, which became standard for all early models. Weights were 5376 pounds empty, 6787 pounds gross, and 7215 pounds maximum."

Now, if you look back at Chuck Hawk's comments of a Spit of similar vintage and average out those "time-to-altitude" figures, do you know what you end up with?

15000 ft. in 5.2 min. :eek:

Exactly the same figure as Joe Baugher states for the first P-40 (incidentaly, that works out to 2884.6153 ft./min.)



Elvis

With the Merlin XII the MkIIa Spitfire shows a climb to 15,000 ft in 5.0 minutes. Climb rate at sea level was 2915, highest climb rate was at 3010ft/min at13000 ft. Climb rates improved dramatically with the MkV, IX and higher.

Time-wise, (September 1940) I think a more accurate comparison would be the P40B or P40C with initial climb rates of 2860 and 2650 ft/min.

Later variants, P40-D,E (Kittyhawk I) needed 8.85 minutes to 14,000 ft. The 'lightweight' P40N could reach 15,000 feet in 7.3 minutes. A Spit IX with Merlin 66 was getting to 15000 feet in about 3 1/2 minutes.
 
Demetrious, the P40 did not have a tactically significant speed advantage over the A6M especially at altitudes above 15000 feet. It just did not have the power available, plus it did not accelerate as well. An interesting footnote is that in tests against the Aleutian Zero the US fighters had difficulty with mechanical problems whereas the Zero just kept performing well. Against the P40F the test was discontinued because the P40 engine could not be made to put out full power. The first production P40, the prewar H81 was the fastest of all P40s with a top speed of just over 365 mph at 15000 feet with military power. The late model N5 to N40s were almost 20 mph slower. The Allison P40K had a sea level rate of climb at just over 2000 fpm. The best advice for a P40 pilot against the Zero was the same as to all USN fighter pilots, "do not dog fight with a Zero."
 
Hello Elvis
Hello Ivan!

Ivan1GFP said:
Typically the climb rate of an aircraft improves slightly as the aircraft goes from sea level to 3000 to 5000 feet and then decreases as the altitude increases. Thus your identical average climb rates to different altitudes doesn't mean the aircraft climb rates are comparable.
Yes, I understand what you're saying and have no reason to doubt you, whatsoever, but if it takes two planes the same amount of time to get from point A to point B, what does it matter if one is faster at a particular altitude, than the other, if it all equals out in the end?


Ivan1GFP said:
This is just a personal opinion, but JoeB is about as reliable as it gets as far as facts and research. I don't believe I can say the same about your other source.
What do you know about Chuck Hawks?
PM me, if you prefer.


Ivan1GFP said:
BTW, for the general discussion, consider that early Allison engine Mustangs had essentially the same engine as installed in contemporary P-40s and were about 30-40 mph faster. That says a lot for aerodynamics. I wonder what would have happened if the P-46 had been developed alongside the P-51.

- Ivan.
Yes, when it comes down to it, the 51 is just a more advanced design that the P-40 could not be "re-designed" to match.
However, this in itself, is a testament to the P-40's design, in that it was still adaptable enough to be of use as a fighting vehicle all the way through the war.
...and not to get too far off track, but since you mentioned the 51, I've always wanted to see a B/C version with the Allison, but setup like the early Merlin (i.e., two-speed, single stage, intercooled).
Would probably put out about the same power (giviing a little more to the Alli's increased displacement...or maybe it would all equal out?), but the plane is lighter by about 300-400 lbs. and better balanced.
Would be interesting to see what improvements, if any, showed up and by what degree, compared to the Merlin version that actually existed.



Elvis
 
Hello Ivan!


Yes, I understand what you're saying and have no reason to doubt you, whatsoever, but if it takes two planes the same amount of time to get from point A to point B, what does it matter if one is faster at a particular altitude, than the other, if it all equals out in the end?

Has a great deal of influence if you are fighting at a specific altitude in which the other a/c excels - like a Fw 190 dueling with a Mustang at 28,000 feet



...and not to get too far off track, but since you mentioned the 51, I've always wanted to see a B/C version with the Allison, but setup like the early Merlin (i.e., two-speed, single stage, intercooled).
Would probably put out about the same power (giviing a little more to the Alli's increased displacement...or maybe it would all equal out?), but the plane is lighter by about 300-400 lbs. and better balanced.
Would be interesting to see what improvements, if any, showed up and by what degree, compared to the Merlin version that actually existed.

Elvis

If the Allison 1710-119 had been available in 1941 there would never have been a Merlin in the Mustang. It later powered the P-82 and was a superb engine with peak Hp in 2000hp range at max boost/water injection
 
Demetrious, the P40 did not have a tactically significant speed advantage over the A6M

Yes it did.

The P-40, in the earlier war, had something in the neighborhood of 20-30 MPH advantage on the Zero, if memory serves, and that's all one needs to extend away from a bandit. You will slip away slowly, but you will slip away. However, that is nowhere near enough to simply "put the hammer down" and expect to be able to run from a bandit in close proximity, especially given the P-40's anemic acceleration. Key to using speed in a P-40 relied on retaining enough energy in the initial attack to put one beyond guns range (at least seven hundred yards to be safe,) at which point one could choose to re-engage, or extend away.

According to data I found on the wide internet after a very non-vigourous search, the P-40C had an 18mph advantage on the A6M2. That's just enough to prevent the Zero from controlling the engagement, but here the superior dive characteristics of the P-40, used in conjunction with it's roll performance and energy retention qualities are what would win the fight. As far as extending/disengaging, a dive to gain the needed distance, followed by a straight run, would probably be enough for the P-40 driver to escape (unless the Zero pilot was keen on tailing him all the way back to his base.) A potential for an escape seems significant to me, though it's not a real game changer. Of course, a 20mph advantage is insufficient to chase down a running Zero, but if you really wanted you could nibble down the distance.

The P-40E, however, also came out in 1941 (which strikes me as a very rapid deployment,) and it's speed advantage was around 30MHPH, which was a bit more useful.

I think the consequences of this- determining the escape potential of a P-40 (which is likely guaranteed the ability to extend past gun range even given a few thousand feet of altitude to dive from,) is "significant," but as for making a difference during the actual engagement, I agree that it was useless.

The best advice for a P40 pilot against the Zero was the same as to all USN fighter pilots, "do not dog fight with a Zero."

The best advice was "don't turn-fight a zero." I'm not sure if that should be equated with dogfighting.
 
One place where the Zero and the P40 were most likely to meet in the early war in any sustained combat would have been at Guadalcanal in late 42, early 43. The P40s were likely to be P40Es and the Zeros were likely to be A6M3s. That P40E had a Vmax of around 360 mph at miltary power at 15000 feet but it dropped off rapidly above and below that altitude. At 20000 feet it could barely touch 330 mph. The A6M3 could do 338 mph at 19690 feet so the P40 would have had to stay at 15000 feet to have a vmax advantage. I still don't believe that is tactically significant. ACM is not won by running away.
 
The chapter in the 5th AF's tactics manual (ca. early '44) about P-40 and Zero mentioned stuff like:

-that the intial anti-Zero tactic had been 'one pass and go home', referring to time period like spring-summer '42 when 49th FG was defending Australia v Zeroes escorting bombers; and per Japanese accounts the RAAF 75th Sdn operated similarly in New Guinea in same period (but Zeroes still held a definite real exchange ratio advantage in those campaigns). In early 1942 campaigns in Philippines and Dutch East Indies P-40's had worse results with 'come as you are' tactics v Zeroes.

-but 'extending away' from Zeroes, ones not yet in firing range, and coming back for more firing passes, was eventually made to work. One issue with that though is it probably mainly reflects experience in New Guinea in 1943 were the radial opponents were Type 1's (Oscars) not Zeroes. In CBI the AVG's initial opponents were Type 97's, against whom they established a winning trend which they maintained against Type 1's, and Type 1's remained the main opponents of the 10th and 14th AF P-40's until later Japanese Army types appeared; Zeroes were only encountered by USAAF fighters in China in a few cases much later on (1944).

-the terminology was 'don't dogfight', though they meant by that, no turning fight.

-escaping a Zero in firing position was always by diving steeply. If the P-40 was too low to dive, it wasn't viewed as any sure thing that a P-40 could stay ahead of a Zero in level flight near sea level (though on paper it should be able to). The instruction in case of Zero on tail at low altitude was porpoise, skid and 'a prayer would come in handy'.

Joe
 
Actually Joe B, another point to add to your remarks. Ira Kepford had an extremely long mission and extremely harrowing one which demonstrates your point in the last paragraph. He found himself on the deck, in an F4U, after flaming a floatplane, being dived on by 3 or 4 Zekes. He forced an overshoot by the leader and shot him down and then went to combat power to extend away. Ran out of combat power and then in full military power could not shake the 2 or 3 Zekes who were slightly above and behind him and his course was taking away from his base. After a while, in desperation, he reefed the Corsair into a tight 180 and one Zeke trying to follow stalled out and went into the water and the other gave up. He got back to base with almost no fuel and exhausted. I think that us armchair "experts" get enchanted with paper numbers, especially vmaxs and think those numbers determine most ACM kills. I have quoted Lundstrom where Wildcats had to fight at 50% throttle to conserve fuel and they survived.
 
I think that us armchair "experts" get enchanted with paper numbers, especially vmaxs and think those numbers determine most ACM kills. I have quoted Lundstrom where Wildcats had to fight at 50% throttle to conserve fuel and they survived.

This. And also this:

t wasn't viewed as any sure thing that a P-40 could stay ahead of a Zero in level flight near sea level (though on paper it should be able to).

Varying with atmospheric conditions, and the pilots skill with engine settings- and perhaps even the quality of the maintenance done on the engine- the P-40s slim advantage might vanish. In actual combat, it was up to the pilot not only to milk every erg of performance from his crate, but to innately understand the fight and secure advantages that, by rights, he shouldn't be able to get.

I think much of the P-40s problems stemmed from the fact that the P-40s advantages were harder to understand and capitalize on, while the Zero's- which was "turn, turn, turn-" was easy and intuitive. There's a reason why most of the newbies in Aces High, the online fighter plane MMO, can be found in Spitfires. (Usually yelling at the other newbies in Mustangs to stop running away and come turnfight. ^_^) I think this is one of the reasons I geek out over the P-40 like a schoolgirl with a new kitten: because a skilled pilot could take a seemingly underpowered and helpless machine and open a giant can of doom with it.

Really, IMO, it was a fantastic airframe. It had a good turn radius, competitive against pretty much anything in the air, an excellent roll rate which was second only to a very few, a decently clean profile, a good armament, a good range, and on top of it all, it was incredibly rugged. The same outdated construction techniques that left it lacking in performance compared to new designs like the P-51 also gave it insane structural strength; the wikipedia page shows a ship that came home with 25% of one wing missing.

If the P-40 had been equipped with a 1500 horsepower Merlin V engine like the Mustang D model had, I think the P-40s potential could have been truly realized.
 
This. And also this:



Varying with atmospheric conditions, and the pilots skill with engine settings- and perhaps even the quality of the maintenance done on the engine- the P-40s slim advantage might vanish. In actual combat, it was up to the pilot not only to milk every erg of performance from his crate, but to innately understand the fight and secure advantages that, by rights, he shouldn't be able to get.

I think much of the P-40s problems stemmed from the fact that the P-40s advantages were harder to understand and capitalize on, while the Zero's- which was "turn, turn, turn-" was easy and intuitive. There's a reason why most of the newbies in Aces High, the online fighter plane MMO, can be found in Spitfires. (Usually yelling at the other newbies in Mustangs to stop running away and come turnfight. ^_^) I think this is one of the reasons I geek out over the P-40 like a schoolgirl with a new kitten: because a skilled pilot could take a seemingly underpowered and helpless machine and open a giant can of doom with it.

Really, IMO, it was a fantastic airframe. It had a good turn radius, competitive against pretty much anything in the air, an excellent roll rate which was second only to a very few, a decently clean profile, a good armament, a good range, and on top of it all, it was incredibly rugged. The same outdated construction techniques that left it lacking in performance compared to new designs like the P-51 also gave it insane structural strength; the wikipedia page shows a ship that came home with 25% of one wing missing.

If the P-40 had been equipped with a 1500 horsepower Merlin V engine like the Mustang D model had, I think the P-40s potential could have been truly realized.
I think that if they had used a large single stage, two (or three?) speed supercharger to give it improved altitude performance it would have been as good as the 109 and Spitfire until late-'42/early-'43.
 
The same outdated construction techniques that left it lacking in performance compared to new designs like the P-51 also gave it insane structural strength; the wikipedia page shows a ship that came home with 25% of one wing missing.

If the P-40 had been equipped with a 1500 horsepower Merlin V engine like the Mustang D model had, I think the P-40s potential could have been truly realized.
It depends on what you mean by construction techniques. The P-40 didn't have the same NACA wing-foil section as the P-51 but generally speaking WWII fighters were of the same aluminium monocoque design as one another. The P-40 was certainly closely related to the P-51 in this respect.
The aerodynamicists-eye view of both planes however, was completely different; the P-51 was considerably more advanced, presumably that is what you meant.

I don't believe the P-40 possessed 'insane' structural strength, it was a hardy ship that could take some but a Hurricane pilot in the Battle of Britain lost two feet of his wing in an encounter. P-38s collided with telegraph poles. P-47s flew through treetops 'collecting firewood' in the mouth of their engine nacelles. All came home.

The P-40F and L were both fitted with Packard Merlins, the L in addition was stripped down in the quest for performance. This gifted it with a mere 4mph gain over the F which was good for roughly 360mph at a rated altitude of 10,000ft. The final variant of the P-40 was the P-40Q and at 420-odd mph it still wasn't as fast as the P-51.
It would not and did not make commercial or tactical sense to introduce a competitor to the P-51 that wasn't as good. The P-40 already had truly realised its potential; at the time the 8th AF were escorting bomber streams into Europe, it was time for something new.
 

Users who are viewing this thread

Back