If no P-51, how would the P-40 have evolved?

[Dcazz7606]

My squadron booklet says the P-40Q's top speed was 426 mph. I don't recall what load or at what altitude. Says with that with the P-38,47 and 51 with equal or better performance there was no need for a 4th. Makes sense. I like the P-40 and the Q would have been a winner a year or two earlier IMO.

I'll correct myself as this booklet says 422 mph at 20,000 ft. The clipped wings reduced the span by two feet.
Also states there were aprox. 300 P-40 R's which were F's and L's that had their Merlins replaced by Allisons because of a shortage of Merlins. No big deal but interesting.

 

[GregP]

The other thing I dug up is that the XP-40Q-1, -2, and -3 all had laminar flow wings simiilar to P-51 wings. The XP-40Q-3 had the wing tips cut down to 35 feet 3 inches. It was a seriously-fast rolling aircraft that could climb with or better than any P-51, possibly other than the P-51J (coincidentally another Allison aux-stage aicraft).

The primary changes from the V-1710-101 to the -117 and -121 were the auxilliary stage gear ratios and the fuel metering calibration. Some of them had the carburetor (actually "fuel metering device")between the Auxilliary stage and the primary stage. Truly a neat engine, and every bit the equal of any high-altitude Merlin of early to mid-1944.

If anyone is interested, we can build one (a -101, -117 or -121), as delivered in 1944 - 1945. In fact, if we look around the shop, we can probably build two since we have two auxilliary stage superchargers in rebuildable condition and all the gear ratios we need to do it along with the "fuel metering devices." Serrious inquiries only, please ... none of this "How much would it cost to build one?" stuff. If you are seriously in the market, you pertty much KNOW how much it will cost to acquire and you also know it will take, probably, in the neighborhood of 12 - 15 weeks to build and test. All our engines come with a guarantee and are run-in until the rings seat and the stacks clean up. We don't sell any "build 'em and ship 'em engines. We RUN 'em in first.

 

[GregP]

Vicenzo,

Regarding post #71. Why would you accuse me of "bad faith?" I simply disagree with your assessment of Allied victory claims for the desert P-40's.

I didn't insult your intergity. In my dictionary, "daft" means slightly crazy ... it doesn't imply bad faith. With the books I have read and the research I have done, the P-40's gave better than they got. You disagree and I assume you have some reason for doubting the reports.

Let's please just agree to disagree. I hope we donl't have to agree to be civil to one another. OK?

 

[[SC] Arachnicus]

From what I have gathered most of the US planes in WW2 were "Boom and Zoomers". Speed, power, and armor. That way of thinking seem to have went all the way to the F4 in Vietnam.

 

[GrauGeist]

From what I have gathered most of the US planes in WW2 were "Boom and Zoomers". Speed, power, and armor. That way of thinking seem to have went all the way to the F4 in Vietnam.

There were plenty of U.S. fighter types that were capable of "turn and burn" tactics and employed them when the situation called for it.

 

[GregP]

Seems to me a lot of people think our planes were boom and zoom, though that term is relatively modern, and does not really apply to WWII fighters.

The most maneuverable fighters of the war, in terms of rate of pitch (which usually defines maneuverability) were the Japanese A6M Zero series, the Ki-43, and probably the Italian Macchi MC.200 series, with the Spitfire being well up there in turn rate but not "nimble" with regard to the fighters mentioned above. However, in Europe, most fighters had a heavier wing loading than the Zero and all were fairly maneuverable with regard to one another … some more than others.

When I think of "maneuverable" in Europe, I think of the Spitfire, Mustang, Fw 190, and Yak-3 … with the Yak-3 on top. When I think of great climbers, I think of the Spitfire and the Me 109. Late model Me 109's climbed VERY well.

Maneuverability can also include rate of roll. A fighter who rolls fast will be able to roll quicker than his opponent he is chasing and put a stream of bullets into the other guy if he anticipates well and rolls / fires quickly.

Of course, the best situation is to be a better roller and turner (pitch) than your opponent. If you had to pick only one it would be a tough choice.

Nevertheless, our fighters were, by and large, maneuverable with regard to most of their competition. Even the P-47 was a pretty good roller with regard to the competition. You might notice it has been voted best WWII fighter in our poll. Oops! Just checked and the P-51 overtook the P-47. Ya' never know, do ya'?

 

[Vincenzo]

Vicenzo,

Regarding post #71. Why would you accuse me of "bad faith?" I simply disagree with your assessment of Allied victory claims for the desert P-40's.

for me this is a confirmation

 

[FLYBOYJ]

From what I have gathered most of the US planes in WW2 were "Boom and Zoomers". Speed, power, and armor. That way of thinking seem to have went all the way to the F4 in Vietnam.

Not really. The F-4 was never meant to dogfight and tactics were developed so it was able to survive in a role it was never intended for.

 

[[SC] Arachnicus]

Yeah the fact they didn't put a gun on the F-4 was almost a disaster.

 

[drgondog]

The other thing I dug up is that the XP-40Q-1, -2, and -3 all had laminar flow wings simiilar to P-51 wings. The XP-40Q-3 had the wing tips cut down to 35 feet 3 inches. It was a seriously-fast rolling aircraft that could climb with or better than any P-51, possibly other than the P-51J (coincidentally another Allison aux-stage aicraft).

The evolution of the lightweight P-51F Mustang - 5 ordered for test Jan 1943, ready Dec 1943. First three 1650-3 Merlin, last two R.M. 14 SM a derivative of the Merlin 100. The latter two were also equipped with Rotol 5 blade prop and designated P-51G

The XP-51F at 7265 pounds cruised at 380/25,000 feet, 466mph at 29000 and ceiling of 42,500
The RM 14 S.M./Rotol five blade prop equipped XP-51G climbed to 20,000 in 3.4 minutes, 495mph at 22,800 with full internal combat load (180 gallons fuel, 4 x50, 1600 rounds), service ceiling 49,000 feet, only restricted because cockpit not pressurized... November 1944.

The F airframe was built twice more with Allison V-1710-119 with 300 hp less than Merlin 100 mod and re-designated as P-51J but had problems with the Allison resulting in cessation of tests. Allison's fixes resulted in the -143.

The P-51H was equipped with the 1650-9 w/1900 w/80 WI overboost - about 100 hp less than modified Rolls 100. Production design on the H started in April 1944 and incorporated multiple changes discovered in flight tests of the XP-51F.

The RAF fitted the same engine in the P-51B (Mk III) R.M 14 S.M. as the XP-51G. It had max climb rate of 4160 at 67" at 14,000 feet - full internal combat load, 453mph from 18K to 25K. The reduction gearing was changed to a slightly lower rpm to achieve better level speed at altitude (suspect supersonic tip issues at altitude). Further engine mods took the Mk III to 30,000 feet under 9 minutes, and a climb rate of 2160 feet per minute at 30,000 feet with 456 mph.

As later experienced with the P-82's the original Packard merlin 1650-9s had speed performance advantage over the Allison 1710-143/145 of about 10mp for same GW.

Note that performance of the P-51B/C (or D/K) could have increased significantly with the R.M 14 S.M Merlin and that a production G was right there with the Ta 152 at altitude in all respects - except faster. The H differed from the XP-51G primarily in powerplant, two extra .50's,taller tail and 50 gallon fuse tank. Intuitively the P-51H would achive very close to XP-51G with same engine and no fuselage fuel as a pure interceptor. It was only marginally slower than the P-80, would climb faster/higher, accelerate better and had much longer range. Had it been needed to counter Me 262 it would have been adequate.

Simply (IMO) the XP-40Q had no chance of continuous evolution like the 51. I don't Know this but I suspect even the redsigned Q had a CDo greater than .022-.024 like the P-38 and would always have a hard time exceeding 430mph. If I had some flight test data I could figure it out.

 

[drgondog]

Yeah the fact they didn't put a gun on the F-4 was almost a disaster.

You can thank Robin Olds and Bob Titus for the F-4E, at least the vocal and constant bitching about having an internal gun on the 105 and nothing but a shotgun pattern pod on the F4C and D. Through 1968 the F-105 had more air to air kills than the F8 and the F4. Most were internal M61 kills.

 

[GregP]

Hi Drgondog,

Let's say we disagree with regard to the development potential of the XP-40Q, but that is pretty much why we do these "what ifs," isn't it?

In my opinion, it should have had another designation since it had a fundamentally different wing. About the only P-40-like thing were the contours of teh tail. So I think it was essentially at the start of its develoment cycle, not the end. The cooling system was different, the engine mount was different, the engine was different, the wing was different, and the basic firewall-back fuselage was similar and, in some cases, identical to a P-40 without the turtledeck. But tehre were a lot of differences.


I wish one were around and flying so we'd at least know more about them. Meanwhile, since they only built 3, I'd say our disagreement is extremely minor ... unless we do more "what if," and I decline in good humor.

 

[GrauGeist]

Of the 3 Q versions, the last wasn't bad looking at all.

XP-40Q-1

XP-40Q-2

XP-40Q-3

 

[wuzak]

Hi Drgondog,

Let's say we disagree with regard to the development potential of the XP-40Q, but that is pretty much why we do these "what ifs," isn't it?

In my opinion, it should have had another designation since it had a fundamentally different wing.

Did it? Or did it have a shortened standard wing?

The XP-40Qs had rearward retracting undercarriage. The Curtiss development aircraft (XP-46, XP-53, XP-60) with laminar flow wings had inward retracting undercarriage.

 

[GregP]

Accoring to what I have as sources, all XP-40Q's had laminar flow wings.

 

[GrauGeist]

OOps...Something went wrong when I posted those pics...lmao

I'll correct that right now...sorry guys :/

(the top photo was a standard production P-40...I overshot my target when selecting the files, I guess...lol)

 

[GregP]

GrauGeist,

I see you are in California, if a long way North. If you ever get around Chino, stop in any Saturday and ask for Greg in the restoration hangar and I'd be glad to show you around.

Cheers!

 

[GrauGeist]

Thanks Greg...I spent a great deal of time at Chino in the 60's and 70's...but it was much different back then!

 

[krieghund]

You can thank Robin Olds and Bob Titus for the F-4E, at least the vocal and constant bitching about having an internal gun on the 105 and nothing but a shotgun pattern pod on the F4C and D. Through 1968 the F-105 had more air to air kills than the F8 and the F4. Most were internal M61 kills.

Putting the gun on it caused havoc with the radar (APQ-120) as when fired the vibration caused the circuit cards to unseat making the radar inop. Another very important addition later in the war and retrofitted to all 'Es" and "Js" were the leading edge slats.

 

[Shortround6]

OOps...Something went wrong when I posted those pics...lmao

I'll correct that right now...sorry guys :/

(the top photo was a standard production P-40...I overshot my target when selecting the files, I guess...lol)

Top photo may have been the XP-40K with radiators and oil coolers relocated to a fairing or 'glove' under the leading edge of the wing between the landing gear. Either the same plane or another P-40K was modified into the first XP-40Q which never had the bubble canopy and kept the radiator/oil coolers in the wing fairing while being fitted with several different engines. It had round wing tips for it's entire life.