P-40 what-if (1 Viewer)

[Clay_Allison]

See the idea of installing a V-1710 with an auxillary stage supercharger has been discussed already.
To save weight I suggest removing two of the six .50 guns. Each gun weighs 70lb, one round 0.3lb. With 235 rounds per gun that saves a total of 280lb. What about laminar flow wings? C&W had designed some for the XP-60.

The best thing would be to get serious about the H.S. 20mm cannon and replace the 6 MGs with 2 cannon.

 

[Markus]

What effect do you think the undercart arrangement is going to have on this? Or are we re-doing that as well?

What´s one more modification for a P-40 among friends? Fun aside, they turned her into the XP-40Q eventually. If C&W had decided to cancel the four different XP-60 versions and improve the well selling P-40 they would have had the P-40Q sooner.

 

[Clay_Allison]

What´s one more modification for a P-40 among friends? Fun aside, they turned her into the XP-40Q eventually. If C&W had decided to cancel the four different XP-60 versions and improve the well selling P-40 they would have had the P-40Q sooner.

That goes for the XP-46 as well.

 

[Markus]

That goes for the XP-46 as well.

They had the XP-46 soon enough and IIRC the USAAF found nothing wrong with it. It wasn´t put in production because the US had joined the war by this time and disrupting C&W fighter production by switching to a very different plane was not tolerable any more. And this was the reason for the rejection of the cancellation of the P-60. Thus C&W deciding to give No.1 priority to a step by step improvement program for the then all-important P-40.

P-40E->P-40F->P-40K->P-40L(early 1943: V-1710+aux. stage SC)->P-40N(mid-43: a K with laminar flow wings)

 

[Shortround6]

They had the XP-46 soon enough and IIRC the USAAF found nothing wrong with it.

Except that it wasn't as fast as a P-40 using the same engine.

It wasn´t put in production because the US had joined the war by this time and disrupting C&W fighter production by switching to a very different plane was not tolerable any more.

Well, disrupting production in order to make a slower airplane certainly wasn't tolerable.

And this was the reason for the rejection of the cancellation of the P-60. Thus C&W deciding to give No.1 priority to a step by step improvement program for the then all-important P-40.

Or that the various P-60s didn't seem to offer any improvement over Airplanes that either were already in production or further along in development. Perhaps the Helldiver fiasco was also on peoples minds.

P-40E->P-40F->P-40K->P-40L(early 1943: V-1710+aux. stage SC)->P-40N(mid-43: a K with laminar flow wings)

Since the P-63 with production model Allisons with 2 stage superchargers don't start to be delivered until Oct of 1943 I would think that early 1943 is a bit optimistic. Contracts for the XP-39E and the P-63 were signed in Jan of 1941.

 

[Clay_Allison]

Seems like we really only had the resources to make one great V-Engine. It's a shame we thought the Merlin was obsolete. We could have killed the Allison V-1710 in its infancy and gone with a V-1650 from multiple sources. Merlin P-40s, Merlin P-39s, Merlin P-38s, that would have been awesome.

 

[Shortround6]

Seems like we really only had the resources to make one great V-Engine. It's a shame we thought the Merlin was obsolete. We could have killed the Allison V-1710 in its infancy and gone with a V-1650 from multiple sources. Merlin P-40s, Merlin P-39s, Merlin P-38s, that would have been awesome.

Problem is that decision would have had to have been made in late 1938 or early 1939. The question is would a 1938 Merlin using American fuel in 1939 have given the performance needed?

At this time American 100 octane fuel was not the same as British 100 octane. The American fuel had a (was required to ) much lower aromatic content which meant a much lower rich mixture octane rating. This means that if you ran a Merlin on American 100 octane fuel you would get better performance than on 87 octane but nowhere near the performance the British got in 1940 using the British spec 100 octane fuel.
using an early Merlin might mean 100 hp less for take-off (or more) than using an Allison in 1939. Given that the American planes were usually heavier this might not be a good thing. it would also affect sea level speed and low level climb.

There were 2 if not three paper studies of putting Merlins into P-38s at various times during the war. NONE of these studies showed any advantage in using the Merlin and in some case showed very large disadvantages in using the Merlin.

The Merlin was never adapted to turbo charging even though it was tried. differences in engine cooling and cylinder head design as given as problems.

 

[Colin1]

...We could have killed the Allison V-1710 in its infancy and gone with a V-1650 from multiple sources...

It was history that hamstrung the V-1710, not technical deficiencies, at least, not in a sense. The V-1710 was having problems even at the C15 model for the P-40, resulting in it losing it's hp rating until much later that year (I'm guessing hp of 1,140 and a de-rated hp of 860 - I'll check when I get home) when the issues were finally resolved but you need to remember that the V-1710 was company funded and Allison wasn't a big company; the Merlin enjoyed the luxury of government funding.

The other skeleton in US inline history is their lack of appreciation of what was going on in Europe and elsewhere, and the outmoded thinking for air combat that prevailed as a result. In light of paying heed to decent intel from those places, and the subsequent down-filtering of the appropriate USAAC requirements to the manufacturers, Allison could well have remodelled (or modelled differently) their approach to power section application.

So with the USAAC keeping their eye on the right ball and more robust funding filtering through, no reason why the Allison unit couldn't have matched the Rolls-Royce unit from the outset.

 

[Elvis]

Seems like we really only had the resources to make one great V-Engine. It's a shame we thought the Merlin was obsolete. We could have killed the Allison V-1710 in its infancy and gone with a V-1650 from multiple sources. Merlin P-40s, Merlin P-39s, Merlin P-38s, that would have been awesome.

I didn't reasearch this, so maybe you're already aware of something I'm not, but I know the Allison dates back to either 1929 or 1931 (don't recall, off-hand, exactly at the moment).
Doesn't that make it an older engine than the Merlin?...maybe even the Kestrel?

...also, "C&W"? Could I get a definition on that, please?


Elvis

 

[Clay_Allison]

I didn't reasearch this, so maybe you're already aware of something I'm not, but I know the Allison dates back to either 1929 or 1931 (don't recall, off-hand, exactly at the moment).
Doesn't that make it an older engine than the Merlin?...maybe even the Kestrel?

...also, "C&W"? Could I get a definition on that, please?


Elvis

Curtis and Wright, IIRC.

Yes, the Allison was older, but as shortround points out often, by 1938 they had delivered less than 100 total engines and were about the size of a racing custom shop.

In 1938 everyone knew war was brewing, that England would get involved, and that AC engines would be needed. A move to adopt the engine of one of the top two fighters on earth and take advantage of shared technological advances wouldn't have been considered that illogical.

Allison would have certainly received orders for license built V-1650s and could have set up their production lines accordingly. What could the war effort have done with >70,000 more Merlins?

A Merlin powered P-51A alone would have had a staggering impact on the war.

 

[Elvis]

Re: company name.
Isn't it "Cutiss-Wirght", with a hyphen, instead of the ""?
Is the name, with the "" an older version of the company's name?
Seeing "C&W" reminds me of the line from The Blues Brothers movie, "We've got both kinds of music. Country AND Western!".


Re: Allison vs. Merlin.
I see what you guys are saying now. Didn't realize production was that low up 'til that time.
Also, concerning your comments about a Merlin-powered P-51A...that is exactly what happened, except we called it the P-51B/C.
Not too much difference between the A and the B/C. Main one was the powerplant!
Check out the performance stats at the Mustangs Mustangs website.
The B/C was a better "hot rod" than the infamous "D"!
Nice thing about the D (other than the bubble canopy) was I think the high G gun jamming problem was finally solved.



Elvis

 

[Clay_Allison]

Re: Allison vs. Merlin.
I see what you guys are saying now. Didn't realize production was that low up 'til that time.
Also, concerning your comments about a Merlin-powered P-51A...that is exactly what happened, except we called it the P-51B/C.
Elvis

Yeah, but think of how much earlier a Merlin P-51A would have made an impact. It probably would have been flying top cover in North Africa and vastly complicating the Pacific Theater in early 1942.

 

[Shortround6]

a problem with the Merlin/P-51 dream is timing.

In 1938-39 the Merlin was a single speed-single stage engine that showed little difference in potential from the Allison. A two-speed single stage version was on offer but in it's original form it showed very little difference in altitude performance over the single speed (the most common single speed version being optimized for high altitude work). It is not until Hooker does his bit that things improve for the Merlin and that is about the middle of 1940. The improved single speed engines (40 series) and two speed engines (XX or 20 series) engines are what is first contracted for with Packard. The American versions power the P-40F. Please note introduction dates for the P-40F and then figure performance for a P-51 with that engine and not the later 2 stage engines.

Work starts on the 2 stage Merlin engine but Allison has started work on a 2 stage engine at the end of 1938!

It takes Rolls-Royce several years to get the two stage engines into production and sharing info with Packard and Packard doesn't deliver any real quantity of 2 stage engines until 1943. These are the -3 and later Packard Merlins.

Allison has development problems with their 2 stage supercharger and development is slower. A good engine once developed it reaches production just a little too late to have any real impact on the war (same could be said of the P&W R4360 on which work started in 1940)

 

[Colin1]

...the Allison dates back to either 1929 or 1931 (don't recall, off-hand, exactly at the moment).
Doesn't that make it an older engine than the Merlin?...maybe even the Kestrel?

Approximately 10 years of development up until the C15 and still with power and reliability issues, against 4 years for the Merlin. This harks back principally to the issue of funding that I pointed out earlier and just as significantly to the USAAC's late acceptance of supercharging over turbocharging, which by 1938 still wasn't doing what it was supposed to be doing as well as it should have been doing it.

There is the fact that the USAAC were gearing up for a different kind of war than the one the ETO would throw at them but that doesn't explain the long development cycle of the Allison quite so directly.

 

[Colin1]

...The V-1710 was having problems even at the C15 model for the P-40, resulting in it losing it's hp rating until much later that year (I'm guessing hp of 1,140 and a de-rated hp of 860 - I'll check when I get home) when the issues were finally resolved...

C15 1,040hp: this could not be maintained owing to low mechanical strength, so in mid-1940 the powerplant was de-rated to 900hp. The original rating was not restored until the end of the same year, after further development.

 

[Markus]

Except that it wasn't as fast as a P-40 using the same engine.

My mistake, I overlooked the 350mph were reached without guns and reduced armour.

Since the P-63 with production model Allisons with 2 stage superchargers don't start to be delivered until Oct of 1943 I would think that early 1943 is a bit optimistic. Contracts for the XP-39E and the P-63 were signed in Jan of 1941.

In April 1942 2,000 two stage Allison engines were ordered. The V-1710-47´s critical altitude was 22,400ft. Early 43 seems doable IF someone make an effort to get the engine ASAP. C&W being afraid to fall behind could have been the one.

Seems like we really only had the resources to make one great V-Engine. It's a shame we thought the Merlin was obsolete. We could have killed the Allison V-1710 in its infancy and gone with a V-1650 from multiple sources. Merlin P-40s, Merlin P-39s, Merlin P-38s, that would have been awesome.

Why do you want to pay RR 6,000 $ per engine if the V-1710 just needs an aux. stage supercharger and an intercooler to be as good? The Allison was stuck with the lesser supercharger not because of technical reasons but because the USAAF did not want a better one. They had 100% faith in the turbocharger and even objected to Allison developing altitude rated engines.

 

[Markus]

Approximately 10 years of development up until the C15 and still with power and reliability issues, against 4 years for the Merlin.

There is the fact that the USAAC were gearing up for a different kind of war than the one the ETO would throw at them but that doesn't explain the long development cycle of the Allison quite so directly.

Strikter US standards. A UK engine had to pass a 100 hour test before being put into production, a US engine had to survive 150 hours. The V-1710 usually failed a few hours short of the 150-mark. Interestingly the first US build V-1650 failed the 150 hour test even worse than any Allison did but was put into production anyway.

See "Vees for Victory" for more.

 

[Colin1]

Stricter US standards. A UK engine had to pass a 100 hour test before being put into production, a US engine had to survive 150 hours...

Thank God they didn't ask for Napier Sabres...

 

[red admiral]

A UK engine had to pass a 100 hour test before being put into production, a US engine had to survive 150 hours. The V-1710 usually failed a few hours short of the 150-mark.

The US 150hour type test consisted of 10x1hr periods of full power and all other time at reduced power. It's challenging to compare this to the continuous running in UK tests.

 

[billswagger]

Has anyone else heard that the P40 could've out performed this spitfire if it had more horsepower?

Pilots claim that contemporary Spitfires were matched in turn performance of the P-40B, but that the P-40 fell behind in performance when the SpitV came out. This also has to do with the fact that the P-40 was given more pilot armor and since it had better range was to be used as an attack aircraft.

I really don't see it as a stop gap aircraft, considering every allied nation used it in service. I just think that when the war called for higher and faster, the plane was no longer fit for the war.

The P-40N was to make up for that but you hear of complaints of how much more maintenance it took because of a removal of parts for weight reduction. Something to consider, but getting more out of the powerplant was probably at the forefront of the original design in 1939, considering that P-43s were to be an alternative to the P-40 in some theaters. I think its reputation for being a tough fighter probably carried it a long way.


Bill