P-51: How early?

[gjs238]

If the politics were right, how early could the P-51 REALLY have been fielded?

 

[drgondog]

If the politics were right, how early could the P-51 REALLY have been fielded?

Depends on what you mean. If you reshape top rank USAAF leader thinking to suddenly say " aha we will need long range escort fighters asap" then two line of approach seem indicated -

1.) place very high priority on supercharged engine capability and
b.) look for airframes with inherent long range capability.

If the 'aha' took place in 1939 (Impossible as top USAAF ranked individuals believed that B-17 and B-24 did not need long range escort) then Republic would have been tasked to develop a wet wing for the P-47, and Allison to develop a supercharged engine and conversations w/Merlin would have started on licensing.

But the 'aha' did not take place until 1943 as the 8th AF was beginning to take serious losses in late 1942 and early 1943.

So, the reality is absent recognition of the strategic impossibility for daylight bombardment doctrine success w/ 1935-1940 technology in bombers, it took the Brits to experiment with a superb aerodynamic platform and mate the Merlin engine into the P-51.

My conclusion is that the P-51B arrived about as fast as possible given the thinking of the 'bomber fraternity' in the USAAF in 1935-1942.

 

[N4521U]

Just to clarify events. Didn't the UK approach the US for a fighter aircraft, specifically the P-40 and were told the US Army was allocated all of production? Whereupon North American, who had never built a fighter, got together with RAF officials and came up with the P-51? It is my understanding the US Army took the first few and stuck them in a hangar to gather dust, because they didn't want to use a BRITISH airplane? And that nothing was done with them until the reports of performance came out of Britain and then used them as test beds for variations? Or am I misguided? cheers, Bill

 

[gjs238]

The escort mission came later, after the fact so to speak.
Even the Merlin powered high altitude performance came later.

The Brits wanted North American to build P-40's under license.
North American offered their own design.

Even if the necessity for European long range escort never arouse...
And the installation of the Merlin engine never came about...
The Allison powered P-51 was superior to the P-40.

I'm thinking two avenues...
- The USAAC takes those two P-51's from the British production, and instead of leaving them to accumulate dust, recognizes a P-40 (and P-39) beater and makes the plane a priority.
- North American's design somehow is "discovered" even prior to the approach from the Brits and makes an even earlier debut. (Wonder how long North American had that design in the can?)

1/14/10: Just edited my post - replaced Republic w/North American - sorry for any confusion.

 

[GrauGeist]

I know that the British wanted North American to manufacture the P-40 under license, I never heard about them asking republic to do it as well...

 

[Airframes]

Bill and Bill are right on the sequence. The British Purchasing Commission went to the USA looking for aircraft, of various types, to bolster the under strength R.A.F., as British industry could not meet the demand in sufficient quantity, fast enough. North American and Schmued's team offered a new design (not even on the drawing board) and, not having built a fighter before, went ahead with the P51, the fist of which, as legend has it, went from drawing baord to first flight in 90 days. Powered by an Allison engine, and entering RAF service as the Mustang 1, the new fighter, although possessing outstanding charactersistics, was not suited to the high-altitude air war over Europe, and was eventually relegated to armed recce duties.
Rolls Royce test fitted a Merlin engine to one, and then a second airframe, with the coolant radiator 'chin' mounted, in similar fashion to the Lancaster, to what became known as Mustang X, and the data etc was passed to North American, who, in turn, carried out their own conversion and development programme, resulting in some major changes, particularly to the positioning of the radiator in the original underbelly housing, now deepend, and 'spaced' from the fuselage, to allow air flow to the cooling system away from the turbulent boundary layer of the underside of the wing/fuselage. Thus, eventually, the P51B wa born, known in R.A.F. service as the Mustang III. And the rest, as they say, is history.
So, as Bill mentioned, with the (then) USAAC thinking and strategy of the time, if the British Purchasing Commission hadn't gone begging for help, and North American hadn't seized an opportunity (at their own risk BTW) then it is highly likely that the P51 would not have seen the light of day until such time as the USAAC/USAAF had learned that a long-range escort fighter was desperately required which, in all probability, would have meant that the first P51's possibly wouldn't have entered US service until late 1944 at best, rather than late December 1943, and very probably much later still.

 

[N4521U]

AF thanks for that. My recollection was a little incomplete, but now I do now recall the whole story from my research from a bunch of years ago. It's amazing how events do unfold. Kind of like our own lives, determined by one split second. Job opportunities, life changes. I know for myself, it was one click of the mouse that I ended up here in Australia, and wouldn't change that event at all. cheers, Bill

 

[Colin1]

...I know for myself, it was one click of the mouse that I ended up here in Australia...

Botany Bay? One click of the mouse? C'mon, own up - what was the name of your prison ship?

 

[drgondog]

The escort mission came later, after the fact so to speak.
Even the Merlin powered high altitude performance came later.

The Brits wanted North American to build P-40's under license.
North American offered their own design.

Even if the necessity for European long range escort never arouse...
And the installation of the Merlin engine never came about...
The Allison powered P-51 was superior to the P-40.

I'm thinking two avenues...
- The USAAC takes those two P-51's from the British production, and instead of leaving them to accumulate dust, recognizes a P-40 (and P-39) beater and makes the plane a priority.
- North American's design somehow is "discovered" even prior to the approach from the Brits and makes an even earlier debut. (Wonder how long North American had that design in the can?)

Not long, only the lower radiator/cowl design was under study from Curtis - but not one line was placed on vellum until the Brits agreed to let NAA do their thing.

1/14/10: Just edited my post - replaced Republic w/North American - sorry for any confusion.

Bill - I agree that the P-51, P-51A and A-36 could have entered significant production for US earlier than it did for the reasons you mentioned.

Having said that it took RAF intiative to modify the Mustang I with the Merlin - then it took NAA several months to redesign the cowl, drop the wing 7 inches and improve the radiator/oil cooler system.

The ONLY initiative in my opinion which could have accelerated the P-51B would have been for RAF to specify a Merlin for the powerplant as part of the original spec - and who could know?

 

[Crimea_River]

I wonder if it would be possible to go from design to prototype on such a plane to today. It's amazing to me that, with all the advances in design technology, the old drawing boards and slide rules could churn out excellent examples of engineering in such a short time. It makes you wonder if we have really advanced or just found far more complex ways of achieving the same results as were done generations ago.

 

[Shortround6]

The ONLY initiative in my opinion which could have accelerated the P-51B would have been for RAF to specify a Merlin for the powerplant as part of the original spec - and who could know?

And with the only two types of Merlin on offer at the time the first Mustang was built being the single speed, single stage versions and the two speed single stage MK XX. It might have helped development but with no intercooler and being a bit shorter and several hundred pounds lighter might still have required a bit of reworking when the two stage Merlin does show up.

 

[N4521U]

United Airlines mate! hehe Bill

 

[timshatz]

I think the question is one of logistics, once the assumption are covered.

Assumptions:
The P51 is recognized as a world beater and is given the highest priority.
The momment of the recognition is fall of 1940 (after the first tests with the Allison engine)

After those two points are established, it becomes a question of the following:

1. How fast is the Merlin recognized as the engine of choice?
2. How fast does Packard start producing the engines?
3. How fast do the Cali and Texas plants tool up to make the aircraft?

Maximum speed for all these events (and this is just a wild guess but what the hell) is something on the order of one month for the recognition of the Merlin, 8 months to start making the Packards (first engine ran in late 1941 from the Packard Plant). But the actual stream of viable engines doesn't start for another 6-8 months. At the same time, the plants in California and Texas are tooling up.

Add in another half year or so just for bottlenecks, boneheads, deadbeats, idiots or, as the Govt calls it, "Fraud, waste and mismanagement" and you're looking at Early 1942. Maybe late 1941.

But the problem with that analysis is it considers everyone in the loop to be compentent and intelligent, that dumb stuff doesn't happen, that Col. "A" doesn't like Col. "B" and sabotages his efforts to bring his project to fruition, ect. In other words, it works like there are no humans in the mix. And that won't happen.

 

[drgondog]

And with the only two types of Merlin on offer at the time the first Mustang was built being the single speed, single stage versions and the two speed single stage MK XX. It might have helped development but with no intercooler and being a bit shorter and several hundred pounds lighter might still have required a bit of reworking when the two stage Merlin does show up.

agreed

 

[gjs238]

It's certainly true that the RR Merlin, and the task of bomber escort, are what the P-51 is remembered for.
However, those events overshadow the fact that the plane had great potential even with the V-1710.
With the V-1710 it was an improvement over the P-39 P-40, and at lower altitudes an alternative to the P-38.

During the 30's the US repeatedly revised performance expectations in reaction to performances being achieved in Europe.
In this context, I wonder how much earlier a V-1710 powered "Mustang" or "Apache" could have been introduced (?)
Might a North American response to the performance challenges (and disappointments) of the day resulted in an earlier introduction of what came to be known as the P-51?
If successfully introduced earlier, and embraced by the powers that be, P-39 P-40 production may have ended sooner. I wonder if this is one of the things Truman was getting at during his investigations post-war (?)

 

[drgondog]

It's certainly true that the RR Merlin, and the task of bomber escort, are what the P-51 is remembered for.
However, those events overshadow the fact that the plane had great potential even with the V-1710.
With the V-1710 it was an improvement over the P-39 P-40, and at lower altitudes an alternative to the P-38.

During the 30's the US repeatedly revised performance expectations in reaction to performances being achieved in Europe.
In this context, I wonder how much earlier a V-1710 powered "Mustang" or "Apache" could have been introduced (?)
Might a North American response to the performance challenges (and disappointments) of the day resulted in an earlier introduction of what came to be known as the P-51?
If successfully introduced earlier, and embraced by the powers that be, P-39 P-40 production may have ended sooner. I wonder if this is one of the things Truman was getting at during his investigations post-war (?)

Well - as the Mustang I it was introduced in combat in ETO four months after the US was in WWII - faster than the P-47, the F4U, the P-38, and the B-24. As the P-51A it went to North Africa about the same time as the P-38 and the A-36 followed shortly afterward.

What did you have in mind?

 

[Colin1]

During the 30s the US repeatedly revised performance expectations in reaction to performances being achieved in Europe.
In this context, I wonder how much earlier a V-1710-powered Mustang or Apache could have been introduced

I'm not sure that's true; the US largely ignored developments in Europe (and elsewhere) during the 30s. In fact, the 40s were under way and information concerning the A6M submitted by Claire Chennault was being comprehensively ignored. Various elements of British procurement consistently commented on the 'good standards of aero manufacture but the lack of suitability for their needs'; US observers in Europe corroborated this view.

Ironically (in my opinion) US development more closely attuned to Europe and elsewhere might well have provided the driver for the earlier entry of the Allison Mustang. In such a scenario, one could speculate the Allison Mustang being the US's Spitfire/Bf109/A6M flagship modern fighter design as early as 1938, although this would make the inclusion of the laminar-flow wing controversial, if not improbable.

 

[Markus]

It's certainly true that the RR Merlin, and the task of bomber escort, are what the P-51 is remembered for.
However, those events overshadow the fact that the plane had great potential even with the V-1710.
With the V-1710 it was an improvement over the P-39 P-40, and at lower altitudes an alternative to the P-38.

In this context, I wonder how much earlier a V-1710 powered "Mustang" or "Apache" could have been introduced (?)

I could hardly agree more, the Mustang's secret of success was the airframe, the engine hardly mattered as long as it was sufficiently supercharged. Now, how do we get a decent supercharger for the V-1710 ASAP?

Oct. 9th, 1939 : The French purchasing commission orders 230 H-81A fighters. One member asks if Allison has advanced (=2 speed) superchargers like P&W and C&W. Currently such SC are not needed but since the more advanced H-81 is likely to remain in service longer than the H-75 they might be needed in the future.
The Allison representative tells they can offer something better. A true two-stage SC that increases to engine's critical altitude to more than 20,000ft.
The eyes of the French open wiiiide.
The Allison rep. cautions the SC is not ready as they have their hands more than full and are a bit understaffed and under funded.

The French cable the info home, French engineers check and confirm Allison's data and the French government decides to finance the 2-stage SC.
When France falls Allison's parent company GM takes over as they are convinced the 2-stage SC has a huge market potential.

As a result the Mustang I is powered by an engine like the V-1710-47(edit: wrong engine number) with a critical altitude of 21,400 ft. The actual P-51A had a V-1710-47 with a critical altitude of 15,500 and made 390mph@18,000ft.

Viola: A high altitude Mustang entering production in April 1941. Not long range though as early Mustangs had only wing tanks with 180 gallons but they could still reach the vital Ruhrgebiet from the UK.


Note that the first actual Allison with a two stage supercharger "flew" in April 1942 installed in the XP-39E. The critical altitude was 21,400ft and quickly increased to 24,400.

 

[renrich]

According to Dean, "America's Hundred Thousand" the British Purchasing Commission asked NA to build the P40 in January 1940 and NA proposed a new design.
April 24, 1940-BPC accepts NA's design proposal NA-73x
May 4, 1940-British approve preliminary design
May, 1940- US Army releases the NA-73x design for sale to British but requires two AC for itself to test
May29, 1940- British place order for 320 Na-73 AC, the 5th and 10th AC to go to US Army, name is Mustang
September, 1940- the British order another 300 NA83 Mustang IIs
September 9, 1940- The first NA-73 is rolled out without an engine and with wheels from a trainer
October 26, 1940- first flight on NA-73
April 16, 1941- The first Mustang I for British is rolled out
July 14, 1942, Rolls Royce makes a study of Merlin powered Mustang
October, 1942- first test flights made of Merlin Mustangs