Did the P40 fly in the Battle Of Britain? (2 Viewers)

[Geoffrey Sinclair]

Early P-40 production and delivers were even more chaotic than that.

I did not think Curtiss was chaotic, certainly experiencing the disorganising effects of rapid growth. Acceptances, plus monthly exports from US and imports into UK

Month	Total Accepted	P-40	Tomahawk I	Tomahawk IIA	Tomahawk IIB	P-40G	US Export	UK import
Jan-40​	0​
Feb-40​	0​
Mar-40​	0​
Apr-40​	0​
May-40​	11​	11​
Jun-40​	25​	19​	6​
Jul-40​	56​	35​	20​			1​
Aug-40​	104​	57​	47​				1​	1​
Sep-40​	114​	51​	63​				22​
Oct-40​	135​	26​	4​	105​			125​	69​
Nov-40​	168​			5​	163​		159​	50​
Dec-40​	165​				165​		186​	161​
Total	778​	199​	140​	110​	328​	1​	493​	281​

P-40B acceptances and deliveries February to May 1941 were 22, 107, 1, 1
P-40C acceptances/deliveries March to May 1941 were 8/7, 175/171, 10/15
P-40D acceptances/deliveries May to July 1941 were 2/2, 20/19, 0/1
Of course getting the aircraft to a USAAF depot is not the same as being operational in an operational combat unit.

In April 1941, P-40C, 10/10 for Britain (actually USSR) and 16/16 for USSR, not exported until September and December respectively.

Having disputed Curtiss chaos it does need to be pointed out how aircraft ordered on the early contracts actually emerged
AC-12414 from 1939, the P-40, P-40D, P-40G and 300 P-40E
AC-15802 from 1940, 100 P-40B and 440 P-40E, under the June 1940 A program
AC-15802 supplement 1, 31 P-40B, the P-40C, 79 P-40E and the early P-40F, under the September 1940 B program.

134 aircraft from AC-12414 paid for by fiscal year 1939 funds, remaining 390 from fiscal year 1940, AC-15802 from fiscal year 1941 funds.

France ordered 100 P-40, then changed 130 P-36 to P-40, a joint British/French order for 500 P-40 followed, Britain took over the contracts then ordered another 150 then 300 more to give the 1,080 total.

 

[Shortround6]

Thank you for that excellent breakdown.
My only question is the P-40G. Perhaps they reused the P-40G designation or perhaps the confusion comes from P-40Gs were rebuilt P-40s or Tomahawks upgraded to be combat capable. In some cases they got new wings that held 4 guns instead of the original 2 gun (total) wings. Most of these were done in Sept/Oct of 1941. Some of them got new serial numbers and some did not. Perhaps it is a typo and it should be July 1941?
I will note that Curtiss built 481 Hawk 75s during 1940 so increase in production was bit slower than it seems. 77 Hawk 75s in March and 83 in April before P-40 production started. July was the peak cross over month with 91 Hawk 75s and 56 P-40s.

 

[Geoffrey Sinclair]

Model Designation Army Aircraft Eleventh Edition compiled by Air Technical Service Command Engineering Division, TSESE-4D4 Wright Field, Dayton, Ohio, January 1945. Model P-40G, Specification No. 98-610, Contract No. AC-20620, 45 Aircraft with Allison V1710-33 engine. Characteristics: Similar of the P-40 except for modifications to provide for installation of Tomahawk wings. Radio command set SCR-183.

It does not explicitly state they were conversions.

Index of AF Serial Numbers Assigned to Aircraft 1958 and Prior.
39-156 to 220 P-40
39-221 P-40G
39-222 to 289 P-40

Report NO. WS-378 (From USAF Material Command Archives). Airplane and Glider Acceptances, Factory Deliveries and Departures from U.S. by type, model and country. Based on contracts active as of January 1940, excluding Navy direct, Navy Lend Lease and Commercial. For period January 1940 to December 1942 inclusive. Prepared by Aircraft Delivery Unit, Statistical Control Office. Dated 6 January 1942, I assume that should be 1943. Has 1 P-40G accepted in July and Delivered in August 1940.

Most probably a retrospective designation, the card for 39-221 has the "redesignated as P-40G airplanes per Mitchell teletype T-S3 in 14 Aug 41" or similar note like the others but it is the only P-40G that is considered built as such.

Joe Baugher at Curtiss P-40G "The designation P-40G was given to 44 existing Army P-40s that were fitted with H81-A2 Tomahawk IIA wings that carried four 0.30-inch machine guns. The first such conversion was P-49 39-221, which was assigned the unofficial designation XP-40G."

39-
162,176,181,187,190,191,196,197,204,206,
209,217,220,221,226,235,238,248,257,263,
267,275,276,279,288

40-
292,297,299,300,301,303,309,315,318,320,
323,331,332,333,335,336,337,338.

total 43, text says 44, the list misses 39-243 and 40-348 which makes the total 45, while 39-181 in list should be 39-182. While serial 39-288 accepted as P-40 redesignated P-40G 14 August 1941, redesignated P-40 30 April 1942.

Defense Aid 31 October 1941 = shipped to USSR, 39-162, 191, 196, 209, 217, 221, 238, 40-297, 301, 303, 309, 318, 320, 332, 335, 336, total 16 (40-332 just has 31 October 1941 date). Also allocated to Defense Aid but not sent, 39-182, 248, 275, 279, 288, 40-300, 40-338

"British repossessed" 39-182 = 42-14269, 40-338 = 42-14261, no other mention of new USAAF serials.

 

[Engineman]

I have read that the Rolls-Royce development unit at Hucknall had several early P-40's for trials and they did scramble for attempted intercepts, but without effect. So, maybe the P-40 does have BoB participation credit.

Eng

 

[jamos]

This Tomahawk IIb didnt do to well Against a ME-109E7

 

[jamos]

I have read that the Rolls-Royce development unit at Hucknall had several early P-40's for trials and they did scramble for attempted intercepts, but without effect. So, maybe the P-40 does have BoB participation credit.

Eng

But the Rolls-Royce Merlin engines were not put in till late 42 correct? I am putting BOB timeframe July-Oct. 1940. Or are you saying they had some Tomahawk Mk1s for testing?

 

[Engineman]

But the Rolls-Royce Merlin engines were not put in till late 42 correct? I am putting BOB timeframe July-Sept. 1940. Or are you saying they had some Tomahawk Mk1s for testing?

Rolls Royce had early Tomahawk aircraft for testing. The exact dates of them trying to attack a raid is not available to me at the moment. The British view the BoB to have finished on the 31st October 1940.

Eng

 

[jamos]

Rolls Royce had early Tomahawk aircraft for testing. The exact dates of them trying to attack a raid is not available to me at the moment. The British view the BoB to have finished on the 31st October 1940.

Eng

ok thanks!

 

[EwenS]

But the Rolls-Royce Merlin engines were not put in till late 42 correct? I am putting BOB timeframe July-Oct. 1940. Or are you saying they had some Tomahawk Mk1s for testing?

Production of the first 699 Packard Merlin V-1650-1 engined P-40F/F-1 (sources vary as to whether they were all designated P-40F or split between the two models) ran between January and August 1942. Production then moved on to later blocks from that month.

Not sure what the first USAAF unit to receive them was, might be 57th FG. It was P-40F equipped when it loaded its 72 aircraft onto the carrier USS Ranger in late June 1942 in time for her departure from Quonset Point on 1 July. They were flown off the carrier to Accra on the Gold Coast and then across Africa to Egypt to join the US Army Middle East Air Force (9th AF from 12th November 1942) Ground crews went by transport around the Cape.

On arrival pilots were seconded to various RAF and Commonwealth squadrons already in the theatre to gain combat experience. In Oct 1942 it began flying missions as a unit.

Another early user was the 33rd FG which loaded its 77 P-40F aircraft onto the escort carrier Chenango in late Oct 1942, and flew them off to Port Lyautey, French Morocco on 10th November 1942.

 

[Frog]

Production of the first 699 Packard Merlin V-1650-1 engined P-40F/F-1 (sources vary as to whether they were all designated P-40F or split between the two models) ran between January and August 1942. Production then moved on to later blocks from that month.

Not sure what the first USAAF unit to receive them was, might be 57th FG. It was P-40F equipped when it loaded its 72 aircraft onto the carrier USS Ranger in late June 1942 in time for her departure from Quonset Point on 1 July. They were flown off the carrier to Accra on the Gold Coast and then across Africa to Egypt to join the US Army Middle East Air Force (9th AF from 12th November 1942) Ground crews went by transport around the Cape.

On arrival pilots were seconded to various RAF and Commonwealth squadrons already in the theatre to gain combat experience. In Oct 1942 it began flying missions as a unit.

Another early user was the 33rd FG which loaded its 77 P-40F aircraft onto the escort carrier Chenango in late Oct 1942, and flew them off to Port Lyautey, French Morocco on 10th November 1942.

Were the 25 P-40 F re-assigned to the Groupe de Chasse GC II/5 "La Fayette" picked from the 57th inventory ?

 

[Geoffrey Sinclair]

Britain reports 1 Tomahawk imported in August 1940, 69 in October.

Air 8/278 says 1 Tomahawk delivered week ending 14 September 1940, next delivery was week ending 9 November, 3 more the next week, then another 14, then 8 week ending 30 November 1940, so 1 in September, 26 in November.

These were all the early ex French order, non self sealing tanks, no armour, French instruments, set up for French guns. And the idea is Rolls Royce was given the only one in the country and as it must have been fitted with guns flew it in combat in September or October? Rather than keeping it for testing given the hundreds soon to arrive?

By week ending 7 September 1940 there had been 12 Buffalo (in July), 54 Mohawk (from July) and 5 Martlet (end August) deliveries, they all had a better chance of being ready to be flown in combat pre 31 October 1940 and were about as survivable, with similar problems making them suitable for RAF service.

The P-40F entered production before the block number system was in place, when a -1 meant export version, P-39D-1, P-40E-1, P-40K-1, production was 699 P-40F, then 123 F-5, 177 F-10, 200 F-15, 112 F-20. All 150 RAF Kityhawk IIa were P-40F, the Kittyhawk II were 56 P-40L-5 and 44 L-10.

The P-40F passed onto France came from RAF and USAAF stocks, the USAAF using Merlin engined P-40 in the Mediterranean.

 

[jamos]

Britain reports 1 Tomahawk imported in August 1940, 69 in October.

Air 8/278 says 1 Tomahawk delivered week ending 14 September 1940, next delivery was week ending 9 November, 3 more the next week, then another 14, then 8 week ending 30 November 1940, so 1 in September, 26 in November.

These were all the early ex French order, non self sealing tanks, no armour, French instruments, set up for French guns. And the idea is Rolls Royce was given the only one in the country and as it must have been fitted with guns flew it in combat in September or October? Rather than keeping it for testing given the hundreds soon to arrive?

By week ending 7 September 1940 there had been 12 Buffalo (in July), 54 Mohawk (from July) and 5 Martlet (end August) deliveries, they all had a better chance of being ready to be flown in combat pre 31 October 1940 and were about as survivable, with similar problems making them suitable for RAF service.

The P-40F entered production before the block number system was in place, when a -1 meant export version, P-39D-1, P-40E-1, P-40K-1, production was 699 P-40F, then 123 F-5, 177 F-10, 200 F-15, 112 F-20. All 150 RAF Kityhawk IIa were P-40F, the Kittyhawk II were 56 P-40L-5 and 44 L-10.

The P-40F passed onto France came from RAF and USAAF stocks, the USAAF using Merlin engined P-40 in the Mediterranean.

But as I read the Merlins were in too short supply to keep putting them in the P-40s when the much superior P-51 was available correct?

 

[Engineman]

But as I read the Merlins were in too short supply to keep putting them in the P-40s when the much superior P-51 was available correct?

The "P-40" Merlins were very different Merlins to the Merlins used in the "P-51".

Eng

 

[Shortround6]

But as I read the Merlins were in too short supply to keep putting them in the P-40s when the much superior P-51 was available correct?

The Merlin in P-40s and P-51s is a bit more complicated. As noted by Mr. Sinclair P-40Ls got Merlins. 600 (?) P40Ls were built from Jan through April of 1943 in five block numbers. P-40Ms and Ns were being built at the same time as the Ls. Ms were built from Nov 25th 1942 to Feb 13th 1943, Ns showed up in March 1943.
P-40s got the V-1650-1 single stage/2 speed engines.
P-51s got the V-1630-3 two stage/2 speed engines, at least to start.
No P-40 got a two stage engine. No P-51 got a single stage Merlin (at least in America).
The Army had been trying to kill off the P-40 for quite some time as it was viewed as being obsolete and they should be concentrating in newer aircraft (most of which failed).

Yes the US cut back on single stage Merlin production from Packard but it was not as rapid as most people think. Packard was making a lot of engines for the British and Canadians.
It wasn't until Jan 1944 that two stage production exceeded single stage production and Packard built over 7,000 single stage engines for the British commonwealth in 1944.
Production was not quite as integrated as some people think. Canada built 164 Hurricanes in 1943 using (?) Packard Merlins. Some say the engines were swapped for RR Merlins when they went to Britian.
An argument could be made that another 150 P-40Ls would have been better than 150 Hurricanes in 1943?
Canceling contracts took a while and for good reason. What was Canada supposed to do with 150-160 sets of Hurricane landing gear in different stages of completion in early 1943 if the contract had been canceled? Or other long lead parts?

 

[elbmc1969]

This Tomahawk IIb didnt do to well Against a ME-109E7

View attachment 890273

The plural of "anecdote" is not "data."

 

[Warhawk1]

My favorite plane from WW2...............Love everything about it

 

[Geoffrey Sinclair]

The original Merlin agreement was for the US to take 3,000 engines, it took 2,813, finishing in March 1943, as has been pointed out they were 1 stage 2 speed supercharged versions, V-1650-1 in US terms, Merlin 28 in British terms. Production of 1 stage engines continued for Britain, Australia and Canada until the end of 1944. The US engines were for 1 XP-40F, 1,311 P-40F and 700 P-40L, total 2,012, giving a roughly 40% reserve. In the end that was not enough and a number of Merlin powered P-40 in the US were switched to Allison. The USAAF P-40 in the Mediterranean were Merlin powered where in theory they could have been given Merlin XX as long as they then used a British propeller. Some Merlin P-40 made it to the Pacific which became a logistics issue.

The Merlin and Allison engine P-40 were built in parallel January 1942 to April 1943, 2,012 Merlin and 3,720 Allison.

P-40E production ended January 1942 (except for 1 in April)
P-40E-1 production December 1941 to June 1942
P-40F production January 1942 to January 1943
P-40K-1 production 1 in May, then June to August, finishing with 1 in September 1942
P-40K production August to November plus 3 in December 1942
P-40M production November 1942 to February 1943
P-40L production January to April 1943
P-40N production March 1943 to November 1944.

The P-40N was meant as a fighter bomber, it did not need the extra altitude performance the Merlin supplied. In March 1943 P-47 production passed 200 a month, accelerating, reaching over 600 in December.

Also as noted the P-51 used the 2 stage 2 speed supercharged Merlin, initially the V-1650-3, delays in getting the engine into production slowed down the Merlin P-51 program, taking to end 1943 to exceed single stage engine production.

721 single stage to 547 two stage in November 1943
576 single stage to 689 two stage in December 1943
954 single stage to 610 two stage in January 1944
631 single stage to 859 two stage in February 1944.

Most non US single stage Merlin were used in Lancasters as well as Mosquitoes. Canada reportedly received 285 Merlin 28 for its RAF order Hurricane production, 144 in 1942 which lacked accessories and so were not flyable, 141 in 1943. In addition it received 480 Merlin 29 for the order for 400 Hurricanes originally meant for Netherlands East Indies/China/USSR, but taken over by the RCAF. All the Merlin 28 were exported to Britain, all Merlin 29 retained in Canada. Apart from a few test flights the 234 Merlin 28 that arrived in Britain attached to Hurricanes were removed for use in Lancasters, with the Hurricanes receiving the RAF standard Merlin XX instead. Just to complicate things 150 of the RCAF order ended up in Britain while almost 80 RAF order Hurricanes stayed in Canada and if they survived long enough received Merlin 29. The British indicate 5,200 Merlin 28 built, 5,165 shipped to Britain, with 228 lost at sea.

Packard built 24,053 single stage Merlins, 49 in 1941, 7,246 in 1942, 9,503 in 1943, 7,255 in 1944, as noted 2,813 for the US, the 3,016 Lancaster III required 12,064 engines, while Canada needed 1,720 for Lancaster and 2,266 for Mosquito, plus the 480 Merlin 29, Australia needed over 400 for Mosquitoes, leaving about 25% of Commonwealth production for spares.

Ignoring the P-51 the RAF confined its use of US built Merlins to Britain and north west Europe.

 

[YavorD]

.... Canada reportedly received 285 Merlin 28 for its RAF order Hurricane production, 144 in 1942 which lacked accessories and so were not flyable, 141 in 1943. In addition it received 480 Merlin 29 for the order for 400 Hurricanes originally meant for Netherlands East Indies/China/USSR, but taken over by the RCAF. All the Merlin 28 were exported to Britain, all Merlin 29 retained in Canada. Apart from a few test flights the 234 Merlin 28 that arrived in Britain attached to Hurricanes were removed for use in Lancasters, with the Hurricanes receiving the RAF standard Merlin XX instead. Just to complicate things 150 of the RCAF order ended up in Britain while almost 80 RAF order Hurricanes stayed in Canada and if they survived long enough received Merlin 29. The British indicate 5,200 Merlin 28 built, 5,165 shipped to Britain, with 228 lost at sea.

I am in a trouble trying to comprehend the Hurricane engine swap!
According to sources known to me, the Merlin 28 engine gear ratio is 0.42 : 1, while Merlin 29 engine gear ratio is 0.477 : 1. Thus, Packard built Merlin 29 is compatible with RR Merlin XX, and with the usual Hurricane II propeller. How one can operate a Hurricane with a Merlin 28? A different propeller? Can someone elaborate on this question, please?

Best regards,
Yavor

 

[Engineman]

Apart from a few test flights the 234 Merlin 28 that arrived in Britain attached to Hurricanes were removed for use in Lancasters, with the Hurricanes receiving the RAF standard Merlin XX instead.

The rebuild of Packard Merlins imported to the UK was very common as Packard built huge whole batches of engines without modifications so that they could produce the volume. Where UK rebuild to incorporate updates was found to be worthwhile, those engines were rebuilt. So, it is not that strange that the Hurricane engines were removed for Lancasters and the Hurricanes got the Merlin XX fitted.

One particular post-UK import Merlin rebuild program was the upgrade of the Conrods of the Packard Merlin's that came in the early batches of RAF P-51B/C. These engines were stripped straight out of the aircraft for the considerable work of fitting the upgraded conrods. Modified engines were then refitted for the aircraft to join the RAF. This was all part of the general UK policy of operating the best mod standard Merlin engines, it was not a criticism of Packard production.

Cheers

Eng

 

[Engineman]

I am in a trouble trying to comprehend the Hurricane engine swap!
According to sources known to me, the Merlin 28 engine gear ratio is 0.42 : 1, while Merlin 29 engine gear ratio is 0.477 : 1. Thus, Packard built Merlin 29 is compatible with RR Merlin XX, and with the usual Hurricane II propeller. How one can operate a Hurricane with a Merlin 28? A different propeller? Can someone elaborate on this question, please?

Best regards,
Yavor

The Merlin .477 ratio was principally for use in the Merlin Spitfire and a few others. Notwithstanding the reduction ratio, there were also differences in the propshaft splines for different propellers and for US/UK Air force requirements. You can be sure that there was a satisfactory combination of, reduction ratios, propshafts and propellers during the engine modifications that I have mentioned. There were also differences in other engine asccessories like Magnetos etc that might have been changed, depending upon the way that the engine was expected to be supported in the Air Force it went to.

Eng