Merlin engined P40

[MiTasol]

Yes there's a name for that, it's called research.
So suddenly because it doesn't agree with you, they don't know what they're talking about about?

Ooookaay then.

You are correct BUT research means getting, reading and comprehending PRIME sources and identifying those sources in your document.

PRIME sources are specifications, contracts, ACTUAL military records, manufacturers and relevant government documents. All else is opinion based on speculation.

If you want to understand what very simple basic real research looks like go to this site but be warned - their index is purely retyped from the index at the end of each microfilm roll and the frame (page) numbers are useless in most cases because when digitizing AFHRA deleted all the blank pages. And on a lot of frames the frame number is not readable.

Other errors are that the person who wrote the original index was not necessarily correct (for example the General Kenney diaries are not where they claim) or did not include much detail.

 

[CD Baumann]

And

Dig out the specification that the P-40 was designed to meet and you will find PURSUIT only. I do not have a copy but at least one copy is floating around here.

As has already been mentioned the model 87 was the first to carry bombs. None of the model 81 aircraft in USAAC/F, RAF or French service carried bombs or drop tanks.

And I've just scoured three books and several websites. It was designed to stay at low altitude. None mention the high altitude requirement that the P38 was designed too. They all say unequivocally that the P40 was bought because it could get brought into production quickly.
There is this thing called strafing too you know? I believe that's qualifies as ground attack.

 

[CD Baumann]

You are correct and research means getting, reading and comprehending PRIME sources.

PRIME sources are specifications, contracts, ACTUAL military records, manufacturers and government documents.

If you want to understand what very simple real research looks like go to this site but be warned - their index is purely retyped from the index at the end of each microfilm roll and the page numbers are useless in most cases because when digitizing AFHRA deleted all the blank pages.
View attachment 794652


Other errors are that the person who wrote the original index was not necessarily correct (for example the General Kenney diaries are not where they claim) or did not include much detail.
View attachment 794653

So what makes everyone think the authors above didn't do that?

 

[MiTasol]

Was there a law saying they could send them to Guadalcanal?

Lend Lease and various other agreements

 

[CD Baumann]

Lend Lease and various other agreements

Then what's it doing on Guadalcanal?

 

[MiTasol]

And

And I've just scoured three books and several websites. It was designed to stay at low altitude. None mention the high altitude requirement that the P38 was designed too. They all say unequivocally that the P40 was bought because it could get brought into production quickly.
There is this thing called strafing too you know? I believe that's qualifies as ground attack.

And I guarantee not one of your books or websites quotes one single line from the actual specification the P-40 was designed to comply with.

And I bet they do not have a bibliography listing a PRIME source for this claim.

Even more if you cut a sentence from any of your websites and drop it in to your search engine (inside quotation marks) you will find multiple other sites that have the exact same sentence because most lazy "researchers" plagiarise from other crap "researchers" and especially from Wakkypedia.

Just opinion based on speculation from reading other poorly researched sources -- or fairy tales from Caiden and other pulp fiction writers.

 

[CD Baumann]

And I guarantee not one of your books or websites quotes one single line from the actual specification the P-40 was designed to comply with.

And I bet they do not have a bibliography listing a PRIME source for this claim.

Even more if you cut a sentence from any of your websites and drop it in to your search engine (inside quotation marks) you will find multiple other sites that have the exact same sentence because most lazy "researchers" plagiarise from other crap researchers and especially from Wakkypedia.

Just opinion based on speculation from reading other poorly researched sources -- or fairy tales from Caiden and other pulp fiction writers.

Sounds to me like your just butthurt because I don't agree with you.

Now open your door, be warned it's going to be bright. And you'll see some green pointy stuff on the ground. It's called grass.
Go touch it.

 

[MiTasol]

Ah yes - the standard reply - attack the person because they presented facts and you only presented myths.

 

[CD Baumann]

Ah yes - the standard reply - attack the person because they presented facts and you only presented myths.

You mean kinda like getting all butthurt and running to your friends to give likes and green checkmarks to artificial bolster your position?

 

[wuzak]

Because close support means generally means ground attack at least in modern parlance. And the last I checked, bombers tend to be in the air when they drop their bombs.
That's not to say they could shoot other planes down because they obviously did.
And I fail to see what the other aircraft you mention have to do with it.

The point of the other aircraft was that they all used, or proposed to use, the M4 cannon, like the P-39, but they were all bomber destroyers.

It was the USAAC's favourite air-to-air weapon for a while.

 

[SaparotRob]

You mean kinda like getting all butthurt and running to your friends to give likes and green checkmarks to artificial bolster your position?

He got the agreement from me because he's right.
FWIW. He gave me my only thumbs down. It was the topic we disagreed on and not personal.

 

[MIflyer]

The P-40 was not designed for low altitude work.

True. With both the XP-37 and the XP-39 the USAAC found that shoehorning a turbosupercharger into a single engined airplane was not easy. The XP-37 worked, with a much higher speed above 20,000 than the P-36, but putting the pilot way back right in front of the fin was unworkable. In the XP-39 the turbo installation actually resulted in so much drag that the airplane was slower with the turbo than without it. So for both airplanes as well as the new Mustang Mk I they set the supercharger on the V-1710 to the happiest medium they could cone up with, for best performance at about 15,000 ft. Setting it for a higher altitude would have hurt lower altitude performance. Personally, I think they screwed up royally by not building a two speed supercharger for the V-1710, which everyone else in the world did with their engines. And I recall reading where a NACA engineer was given the job of improving the V-1710 and complained it was a waste of time with that "piece of junk." The V-1710 was better than the Merlin in some respects, being lighter, easier to repair, easier to build and easier to maintain, but its supercharager condemmed it.

By the way, the 37MM gun on the P-39 could NOT bust tanks. The muzzle velocity was too low. It waa designed for air-to-air combat.

Now, the A-36A was designed for ground attack and was powered by a V-1710 that gave its maximum speed at 5000 ft.

None of the model 81 aircraft in USAAC/F, RAF or French service carried bombs or drop tanks.

But according to Curtiss the Hawk 75 could.

 

[MiTasol]

Yes and the C model could carry a bomb on the centreline as well as shown in your post.

It could also be fitted with a centre line 52USG fuel tank as a customer option but the USAAC rejected that proposal. From the primary source identified below:-

This policy changed two days after the Japanese attack on Pearl Harbor and the USAAF immediately started the process to have the 75 gallon drop tanks that Lockheed wanted to fit to the P-38 approved for manufacture and use. I have, at this time, found no start date for the P-40 drop tank process.

Note that it took until April 3, a total of 116 days, to get those tanks, that apparently had already been built in small quantities, to the stage where the USAAF was willing to place an order. Note also that the contractor was given a further 60 days to start deliveries of the mass production tanks.

In relation to the P-40 drop tanks the USAAF first initiated action to produce these tanks on 28 February 1942 and that the tank to be produced was the same part number 75-45-433 proposed for the P-36C and available as a customer option on export H-75 (P-36) aircraft.

The phrase initiating action to procure can be read several ways with the shortest time frame being that Curtiss or some other P-40 tank manufacturer had already completed their preproduction tasks such as the blueprints, the creation of all the tooling needed, creation of test assemblies, flight, vibration and drop testing of those prototype units, and had then made the necessary refinements as required. This would have been followed by an order which, like the Lockheed P-38 tanks, would have included a requirement to deliver the first examples within 60 days so we are looking at May 1st as the earliest realistic date these tanks could have entered service.

Additionally of course the aircraft had to be modified to carry the tanks. Given the modification documentation, and flight manual documentation, also had to be created, tested, and approved, PLUS the required components had to be purchased or manufactured, collated and delivered prior to the tanks actually being fitted shows that even a May 1 operational start date was optimistic.

Fortunately the RAF Kittyhawk aircraft carried drop tanks so the design and testing had already been completed for or on behalf of the RAF and low level production by Curtiss or a subcontractor existed Instantly scaling production would have been impossible without additional staff and tooling and those both take time to train and obtain.

 

[Shortround6]

I will note that the USAAC wanted only air cooled engines on attack planes starting with the A-12 which was a re-engined A-8 basically. The USAAC did not buy another liquid cooled attack plane until the A-36 and that was a funding trick to keep the P-51 Mustang production line open until more funding could be found for Pursuit aircraft. At the time the A-36 order was placed there was no money left in the budget for Pursuit Aircraft but they hadn't spent all the money in the "Attack" account.
Not actual "proof" but one more circumstance.

Another circumstance, not only did Curtiss put out some ads for Curtiss 75A as a fighter bomber as shown by MIflyer there is a 24 page brochure on the 75A here.
http://www.wwiiaircraftperformance.org/P-36/Curtiss_Hawk_75-A_Detail_Specifications.pdf
See pages 16, 18, 20 & 21
It is undated but judging by the engines used it is probably from 1939. Both P&W and Wright were exporting higher powered engines in 1940.

Curtiss already had the bomb beams, racks and mounts designed up to 850lbs of bombs for the Hawk 75A/P-36 when they were ordering the P-40 (or in process of ordering it) and they never asked for modification or change in the contract to get a better plane for ground attack until well into 1941?
The P-40C got the ventral tank and was in production in March/April of 1941. Due to the internal self sealing tanks in the P-40C compared to the external sealed tanks of the P-40B fuel capacity was cut considerably and the under fuselage 52 gal tank pretty much restored the original range/endurance.

As noted by MiTasol there is a difference between testing something and listing it in manuals and providing spare drop tanks in quantity.

Another circumstance, The P-40 and P-39 were given engines with 8.77 supercharger gears. The engines in the YP-38 and XP-39 used 6.44 supercharger gears. This allowed for about an extra 100hp for take-off and at low altitude. The P-38 kept the 6.44 gears through the E model and then changed to 7.48 gears, the same gears that were used in the A-36 engines.
Allison engineers were not dumb, They gave the Army the best performing engine they had at the time at altitude. They had options available for more power at low altitudes (say 5000ft?), but less power at 14,000ft. The Army didn't want them.

There is some dispute about if the the XP-38 used B-1 or B-2 GE turbos. The YP-38s and through the Es they used B-2s. The XP-39 used a B-5 turbo (?) the P-38F & G used B-13 turbos. They were fooling around with the turbo controllers ( and 3rd supplier) with the Army acting as the coordinator. Turns out the early army designed controllers were crap (fundamentally flawed) and a new type of controller was needed.
The Army was well aware of the state of the turbo engines in 1938/39/40. and even into 1941-42.

The case is very strong that Allison was left behind by developments by Britain and Germany in 1940-42 that significantly improved their aircrafts performance at altitude.
It didn't help that that the US over-loaded the ever loving crap out of the P-40 and P-39 with the P-40E gaining 1145lbs of weight (clean with only 120 US gal of fuel) over the P-40 no letter and using pretty much the same engine (beefed up a little and a new reduction gear). P-40E carried 38% more guns and ammo than a Spit VC or Spit IX.

Without primary documentation for the ground attack or low altitude role I am not buying it.

 

[MiTasol]

There is some dispute about if the the XP-38 used B-1 or B-2 GE turbos.

Either the XP-38 or a YP-38 is at Planes of Fame at Chino. GregP will know for certain which one. He may be able to identify which turbos are fitted though from memory the plate is not visible when installed

 

[MIflyer]

USN, USMC, and USAAC Pursuit aircraft, especially those built by Curtiss, had been carrying drop tanks and bombs for over a decade before WW2 started. The USN even modified the Curtiss F11C-3 into a dive bomber, the BF2C-1. (I have three or four 1/48 Lindberg kits of that; how have I missed doing a conversion?). And of course the USMC "Invented" dive bombing using Curtiss fighters, which impressed the hell out of a guy named Udet, who bought one. Aircraft were not seen as strategic weapons in the USA but mainly were supposed to support ground forces. Pursuits carrying bombs was important.

How many European fighters were thought of as being suitable for carrying bombs? They built light bombers and dive bombers.

The P-38 kept the 6.44 gears through the E model and then changed to 7.48 gears, the same gears that were used in the A-36 engines.

You'll see a "fin" sticking up on P-38 booms that Just So Happens to be in line between the turbo and the cockpit. The reason was that with the earlier gear sets they had to boost the tubso so high at high altitude that they had shown a tendency to come apart and fling shrapnel into the cockpit. According to Lt Col Ward Duncan, 9th PRS Maintenance Chief, that is why they raised the gear ratio in the V-1710 mechanical superchargers. The 9th started out with F-4's (P-38E) and even had one engine that seemed to have been a V-1710C with a F series gearcase.

 

[Shortround6]

USN, USMC, and USAAC Pursuit aircraft, especially those built by Curtiss, had been carrying drop tanks and bombs for over a decade before WW2 started. The USN even modified the Curtiss F11C-3 into a dive bomber, the BF2C-1. (I have three or four 1/48 Lindberg kits of that; how have I missed doing a conversion?). And of course the USMC "Invented" dive bombing using Curtiss fighters, which impressed the hell out of a guy named Udet, who bought one. Aircraft were not seen as strategic weapons in the USA but mainly were supposed to support ground forces. Pursuits carrying bombs was important.

How many European fighters were thought of as being suitable for carrying bombs? They built light bombers and dive bombers.


You'll see a "fin" sticking up on P-38 booms that Just So Happens to be in line between the turbo and the cockpit. The reason was that with the earlier gear sets they had to boost the tubso so high at high altitude that they had shown a tendency to come apart and fling shrapnel into the cockpit. According to Lt Col Ward Duncan, 9th PRS Maintenance Chief, that is why they raised the gear ratio in the V-1710 mechanical superchargers. The 9th started out with F-4's (P-38E) and even had one engine that seemed to have been a V-1710C with a F series gearcase.

that is another thing that that does NOT line up with the P-40 being designed for low altitude work or for ground attack.
The P-26 was supposed to be able to carry five 30lb bombs or two 100lb bombs (or 116lb?)
The P-35 was supposed to be able to carry 300lbs of bombs (exact number and types not given?)
The P-35A (ex Swedish aircraft) were supposed to carry 350lbs (?) but they post date the P-40.
But the ground attack (or low level) P-40 was supposed to use just a pair of .50 cal guns? (the wing guns were added)

Turbos.
I don't know if it was a chicken and the egg thing or not. GE used a different material at some point in 1942 (and that covers a lot of ground ) that allowed for higher rpm of the turbine.
Not sure if there were other changes. The Armor screen did go away.
The 1150hp P-38s were supposed to use 40.3in of MP, the 1325hp engines were supposed to use 47.0 in and the 1425hp engines were suppose to use 51.0 in.
The 1150hp engine in the P-40E was supposed to use 44.5in MP.

 

[MIflyer]

But the ground attack (or low level) P-40 was supposed to use just a pair of .50 cal guns? (the wing guns were added)

I think that the P-40 was a lash-up that was needed quickly. The USAAC committed to turbocharged power enabling superior performance at high altitude (never mind that they were forced to copy captured Luftwaffe oxygen equipment) but things did not go smoothly. The P-39 proved to be incapable of handing a turbo and the XP-37 was a success, but also unworkable. The XP-41 showed what the P-35 could become, with further refinement and a two stage mechanically supercharged engine but Seversky's AP-4 turbocharged version quickly outshone it and showed the way to go. The turboless P-39 and P-40 were the best they could go into full production with in 1940-1941.

And the fact that those American types were better at ground attack than their European equivalents reflects not so much US successful planning for that role but rather lack of planning across the pond.

 

[MiTasol]

According to Lt Col Ward Duncan, 9th PRS Maintenance Chief, that is why they raised the gear ratio in the V-1710 mechanical superchargers. The 9th started out with F-4's (P-38E) and even had one engine that seemed to have been a V-1710C with a F series gearcase.

That would not work as the C series accessory gear box (housing supercharger and magneto drives etc) was driven by a shaft from the propeller gear box.

On the E and later engines, like the F used in the P-38, 40 and 51 the accessory gearbox is driven off the rear of the crank shaft.

 

[MIflyer]

On the E and later engines, like the F used in the P-38, 40 and 51 the accessory gearbox is driven off the rear of the crank shaft.

Well, the engine in question had a completely different coolant attachment from all the others.