Whirlwind replacement in 1943 but no Typhoon--Would a Mustang I or II, or the A-36 be considered if enough to go around?

[BarnOwlLover]

P-40s were out of service in the northern ETO by 1943 as far as I know.

 

[hobbes154]

Yeah, cause they had Typhoons! But this is about what happens if there is no Typhoon.

I'm being a bit unfair since the OP said "if enough to go round". Really the answer to the question is just "yes" as that's what the Brits already used their Mustang Is and IIs for. But realistically the Allison Mustangs stop production in early 1943 so there won't be any more to replace the Typhoon.

Purely on the merits I'm not sure which of a P-40 or an Allison Mustang/Apache is better as a fighter bomber. Possibly it would depend on if you're more worried about fighters or flak (Mustang being faster but P-40 cooling system maybe a smaller target). Conflicting opinions:

When the Tomahawk was used by Allied units based in the UK from February 1941, this [altitude] limitation relegated the Tomahawk to low-level reconnaissance with RAF Army Cooperation Command and only No. 403 Squadron RCAF was used in the fighter role for a mere 29 sorties, before being replaced by Spitfires. Air Ministry deemed the P-40 unsuitable for the theater. UK P-40 squadrons from mid-1942 re-equipped with aircraft such as Mustangs[clarification needed]​
Curtiss P-40 Warhawk - Wikipedia

They didn't give me Mustangs but they gave me one personally to play with to sort of abate my wrath a bit, but actually the Kittyhawk was better than the Mustang for doing the job that the Kittyhawks were doing. It is very robust. It is very solid. It has a minimum amount of plumbing for radiator and oil and that sort of thing - the Mustang has a radiator way back and there's a lot of plumbing and you can get bullets through the pipes which causes you problems.
Jack Doyle Interview

What other option is there? P-38 or P-47? USAAF is taking them all. Hurricane? Too slow. Beaufighter? Also slow, less maneuverable and in demand for a lot of other roles. Mossie? Faster but again demand > supply.

 

[BarnOwlLover]

Problem is in real life, is one, the Allison P-51s production was curtailed by the Merlin Mustangs (that by that time were even more needed/desired, especially in the ETO), and two, the Allison Mustangs were much needed and wanted by the RAF especially for the tactical recon role, for which they were used all the way up until the end of the war.

That said, the A-36 and P-51A were rated for 2 500 lb bombs, the same as the Whirlwind and early Typhoon ground attack mission aircraft (were rated for 2 1000 lbs later after some upgrades). P-51s wouldn't be rated for 2 1000 lb bombs until 1944 I think, and that was basically the P-51B and later.

 

[yulzari]

Can anyone direct me to a convenient reliable source of low altitude maximum continuous speeds of the Hurricane IV, Allison Mustang, late Kittyhawk, Typhoon and Whirlwind each with a pair of 500lb bombs?

As an aside, the Allison Mustangs were a one time acquisition which became a depleting resource in airframes, engines and spares. That resource was carefully husbanded to keep up the operations of low level PR Mustangs in the RAF as the preferred airframe in NW Europe so Allison Mustangs would need a separate production line.

 

[tomo pauk]

As an aside, the Allison Mustangs were a one time acquisition which became a depleting resource in airframes, engines and spares. That resource was carefully husbanded to keep up the operations of low level PR Mustangs in the RAF as the preferred airframe in NW Europe so Allison Mustangs would need a separate production line.

Allison Mustangs were not the one time acquisition.
There was the acquisition of the Mustang I (4 HMG, 4 LMG), Mustang Ia ( 4 cannons), as well as Mustang II (different engine, wing racks).
Americans bought all of the three, too, plus the A-36.

 

[ColFord]

Where do I begin.

Curtiss P-40s (P-40D and onwards) in ETO. Evaluated early on by the RAF as being unsuitable for operational use in the ETO due to a range of different factors. Curtiss Tomahawks, primary operational user in ETO was by Army Co-operation Command, and despite what is posted on a number of online sites they were used operationally by the ACC Squadrons for sorties over occupied France and Belgium and along the Dutch Coast. Re-equipment with Mustangs from Tomahawks commenced January 1942, with a number of ACC Squadrons converting from Tomahawks, or in some cases directly from Lysanders from March 1942 onwards and picking up pace thereafter. In a couple of case, ACC squadrons that were in second line areas eg Northern Ireland kept using the Tomahawks into early 1943, but their use could not be considered operational and they were plagued with serviceability issues. The front line operational ACC Allison Mustang squadrons also normally had a couple of Tomahawks kept on strength until at least March-April 1943 to make use of the vertical camera installation that was fitted to some Tomahawks - ntil such time as sufficient numbers of Mustangs were modified with the vertical camera installation, and also as a trainer/hack. But again, increasing serviceability issues and a number of accident due engine failure saw them pretty much gone by May 1943. The remaining Tomahawks in the UK after that were primarily in the non operational Fighter Affiliation Flights whilst they could keep sufficient numbers airworthy.

Allison Mustangs were certainly not a one time acquisition, with the RAF repeatedly trying to secure more after the initial direct purchase NA-73 & NA-83 Mustang I (total 620) and first Lend Lease order for the NA-91 P-51 Mustang / Mustang IA (150 aircraft, 58 retained by US, 92 delivered to UK). UK was looking to secure further deliveries of Allison engine Mustangs after the initial Lend Lease order, with a view to broader utilisation based in UK and potentially expanding into MTO if supply permitted - which it never did. US entry into the war after Pearl Harbor saw USAAC/USAAF requirements over riding UK requirements. If they could have secured more NA-99 P-51As along with associated engine and airframe spares, RAF would have grabbed them.

Very basic reason why Allison engine Mustang could not continue alongside Merlin engine Mustang production was about tooling and production capacity at NAA. If you look at the manufacturing tooling for the P-51B/C Mustang and compare it to the Allison Mustangs, the early Merlin Mustangs contain a significantly high number/percentage of individual components and assemblies that carry NA-73, NA-83 and NA-91 with a decreasing percentage of NA-97 and NA-99 part numbers. To keep the Allison Mustangs in production would require duplication of a lot of tooling and likely establishment of another Mustang production line somewhere - with all the attendant delays in commencement of production, etc. The production resources and raw materials would also have to be drawn from some other program - what will the USAAF cut to keep the Allison Mustang production going alongside the Merlin Mustangs.

It is telling that the RAF's initial allocation of Mustang IIIs was not to Squadrons allocated to Fighter Command, but to 2TAF. Those squadrons when they first got their Mustang IIIs, the initial focus of their operational training after their conversion onto the Mustang III was not air to air, but air to ground, making use of their range and bomb carrying capabilities. It was the crisis in long daylight range bomber escort that rapidly had these squadrons retasked with bomber escort and fighter sweeps supporting the daylight bombing campaigns - both by RAF and USAAF medium bombers and USAAF heavy daylight bombers. Playing into that was the larger percentage of early Merlin Mustangs allocated to the RAF that were not fitted or retrofitted with the fuselage fuel tank in the early stages of the RAF's use of the Mustang III - that increased their potential bomb carrying loard but reduced their potential escort range. After D-Day, when the 2TAF units with the Mustang III moved to ALGs in France, they started to regularly carry 2 x 1000lbs bombs as their operational payload.

Similarly to the quote from the RAAF pilots about his preference for the Kittyhawk for what they were doing in the MTO, there were similar quotes coming from RAF pilots who were brought back from the MTO to the ETO before D-Day who realised that the threat and operational environment in the ETO was different to that in the MTO. That then influenced which aircraft were best for the various roles there.

A salient point to note is, that none of the Mustang I or Mustang IA were built or configured to carry underwing hardpoints. A&AEE modified some Mustang I to test the "Low Attack WIng" concept for carrying a range of underwing stores - bombs, drop tanks, SCI, RP rails, 40mm Vickers S guns - but that didn't progress due to the availability of........the Typhoon. Even when the RAF received its 50 NA-99 P-51A Mustang / Mustang II, operationally they did not operate them with the underwing stores carriers fitted - for their low altitude Tac/R role no requirement.

To keep the number of Allison Mustangs required for D-Day and beyond, the RAF went down the path of maximising every available airframe they could. This meant repairing aircraft that would have previously been declared 'written off', doing a bit of 'frankensteining' of major airframe components between aircraft written off to create a usable aircraft, and running 'unmodified' early production Mustang Is that had been related to non-operational use at 41OTU - the Army Co-operation and Tactical Reconnaissance OTU - through a program to bring them up to operationally modified status, and replacing them with Hurricane IIs at the OTU. It also saw the requipment of a number of the 'second line' ACC Mustang units to other types such as the Hurricane II and Spitfire V, with the Mustangs released from those units overhauled and placed into the group pools for the operational units that would need them as replacements. It was the run down in numbers of available Allison Mustangs for the RAF's Tac/R squadrons in 2TAF that saw some of them re-equipped with the Spitfire FR.IX, the plans for the Typhoon FR.1b and PR.1b - eventually only about 100 built and then not particularly successful in the role; and eventually with the Spitfire FR.XIV, which again was regarded as a stop gap until the Spitfire FR.XVIII was available.

As for low altitude maximum continuous speeds, the operational profiles flown in the ETO would require the speeds to vary depending on the distance to the target, how far inland the target was, the type of target, etc.

 

[BarnOwlLover]

To relate to a point made, here's a IWM photo of a RAF 2ndTAF P-51B (Mustang III) fitted with a 1000 lb bomb under each wing:

And video of RAF Mustang IIIs in a similar configuration:


View: https://www.youtube.com/watch?v=1JS5oxqV-Kg

 

[tomo pauk]

To keep the Allison Mustangs in production would require duplication of a lot of tooling and likely establishment of another Mustang production line somewhere - with all the attendant delays in commencement of production, etc. The production resources and raw materials would also have to be drawn from some other program - what will the USAAF cut to keep the Allison Mustang production going alongside the Merlin Mustangs.

Thank you for the very informative post.

USAAF has no role for the Vultee's dive bombers, so there is where a production line for the Mustangs would've been great. Similar for the Curtiss Wright production line at St. Louis.
Tooling up Bell for production of Mustangs during the winter of 1942/43 would've also been a much better deal than insisting on the late marque P-39s and any P-63s.

 

[SaparotRob]

Expending resources on the P-63 does seem wasteful. Keeping the P-51A in production would seem a better way to those factories production lines running. How would the timeline fit the changeover?

 

[Shortround6]

Russia got around 1/2 of the P-39s built.

Bell splits their factory space/workers in half and builds P-39s for the Soviets and Allison P-51s for America?
Or sends Allison P-51s to the Soviets?
Or?

 

[SaparotRob]

Or, I want one.

 

[EwenS]

Russia got around 1/2 of the P-39s built.

Bell splits their factory space/workers in half and builds P-39s for the Soviets and Allison P-51s for America?
Or sends Allison P-51s to the Soviets?
Or?

Rather more than that went to the USSR. 3,303 P-63 built, with production aircraft rolling off the production line from Oct 1943. Numbers supplied to the USSR vary by source with the lowest being 2,397 and the highest 2,672 (possible overstated) or 73% to 81%. AFAICT the Lend Lease deliveries began around spring 1944.

Edit. Sorry misread this.

P-39 - 9,588 built of all versions. 5,067 sent to the USSR including 265 (212 arrived) aircraft shipped from Britain. Many of those sent (2,744) were on the British Lend Lease account.

Edit 2:- The Soviets got 4 or 10 (sources vary) NA-73 Mustang I from the RAF. They weren't impressed. Yefim Gordon noted this about the results of their tests.

" As a tactical fighter, it was inferior in manoeuverabilty to contemporary Soviet and German fighters, as well as to the P-39 and P-40"

So they didn't request any more Mustangs (Allison or Packard Merlin powered) through the Lend Lease system.

 

[tomo pauk]

Russia got around 1/2 of the P-39s built.

Bell splits their factory space/workers in half and builds P-39s for the Soviets and Allison P-51s for America?
Or sends Allison P-51s to the Soviets?
Or?

They get more P-40s.

 

[ColFord]

Rather more than that went to the USSR. 3,303 P-63 built, with production aircraft rolling off the production line from Oct 1943. Numbers supplied to the USSR vary by source with the lowest being 2,397 and the highest 2,672 (possible overstated) or 73% to 81%. AFAICT the Lend Lease deliveries began around spring 1944.

Edit. Sorry misread this.

P-39 - 9,588 built of all versions. 5,067 sent to the USSR including 265 (212 arrived) aircraft shipped from Britain. Many of those sent (2,744) were on the British Lend Lease account.

Edit 2:- The Soviets got 4 or 10 (sources vary) NA-73 Mustang I from the RAF. They weren't impressed. Yefim Gordon noted this about the results of their tests.

" As a tactical fighter, it was inferior in manoeuverabilty to contemporary Soviet and German fighters, as well as to the P-39 and P-40"

So they didn't request any more Mustangs (Allison or Packard Merlin powered) through the Lend Lease system.

The NA-73 Mustang I the UK sent to the USSR (over the objections of the Air Ministry) were all 'pre-loved', had not had the modifications done required to fix a number of the issues identified in the early pre-production and production batches. I've seen suggestions in a couple of the AM files that the disassembly of the aircraft that were sent was done in rather a hurry and not with all the due care and attention to detail as if the aircraft were being shipped for the RAF's own use elsewhere. So not surprising the performance out of the aircraft when they were reassembled and tested by the USSR was less than stellar.

 

[Geoffrey Sinclair]

P-39, 1 prototype, 9,588 production versions. As of June 1945, 4,874 delivered in USA for USSR (2,744 on UK account), plus 50 more P-39Q diverted from USAAF deliveries, with 4,843 exported. The book Roads to Russia has 4,746 arrivals in the USSR from the USA (2,718 ALSIB, 108 North Russia, 2,020 Adaban) The US official history has 2,030 via Adaban, including 3 in 1945.

Britain says 480 P-39 imported June 1941 to July 1942, with 281 exported to USSR November 1941 to September 1942 plus another 9 in June 1943 (PQ18 ships were loading but things changed with the PQ17 losses). AIR 22/310 Mid October 1942 report has 189 actually sent, plus another 10 for spares, 39 lost at sea. Final report has 255 sent, 202 arrived, 53 lost at sea under 1st to 3rd protocols, plus 10 more as spares, plus 1 "In error" to Middle East and believed then to USSR.

P-51 Four from UK to USSR AG348, AG352 to 354 (on charge November/December 1941) officially sent December 1941, arrived in USSR at the latest March 1942. Officially 32 Mustang imports into UK by end December 1941.

North American Inglewood had around 25,000 employees in January 1943, 24,500 in December, Dallas had 22,400 and 36,000, Kansas City 14,400 and 22,000. The A-36 in October 1942 were the first of the family to have wing racks.

P-63 2,339 delivered in USA for USSR plus another 85 on UK account, total 2,424, 2,373 exported by end June 1945 when deliveries ceased, no data on July 1945 and later exports, Roads to Russia has 2,400 arrivals by 20 September 1945, 3 via Northern Russia, the rest ALSIB.

The 3,303 P-63 included 3 prototypes and 332 RP-63 targets.

Curtiss started its P-47 acceptances in September 1942 from a contract signed on 31 January 1942. Given who wanted the P-39 and P-40 the least disruptive alteration to history would be to change the order to P-51 and phase out P-40 production during 1943.

According to the RAF Census the RAF placed an order for 384 Hurricane V in June 1943, upped that to 584 in August, cancelled it in January 1945, the chosen Merlin 27 engine began production in November 1943, with 141 built before the order was cancelled, they mostly became Merlin 25 for Mosquito.

The problem for the British in 1943 was Sabre production and reliability resulting in the reduction to spares of hundreds of Typhoon airframes in 1943, as of end September 1943, there were 239 Typhoon in operational units, 15 in OTU, out of 913 available after 603 losses, there had beem 1,516 deliveries. Meantime the storage units held 90 operational and 888 non operational Sabre.

To a first approximation the Westland Welkin, first 2 in September 1943, was the upgraded Whirwind.

When it comes to seeking Vengeance on the Vultee Vengeance the Nashville factory peaked at 766 aircraft in 1943, 80 per month at maximum, Northrop produced 400 of the dive bombers, Nashville 1,529, over at Brewster 1 prototype and 769 production Bermuda.