An Allison V-1710 with a two-speed supercharger in 1942 (1 Viewer)

[Shortround6]

There is also the issue, as I noted previously, of the ~4,000 Packard Merlin XX / 28 which ended up in Canada and in aircraft which were as far as I've been able to determine mostly not involved in the war. Presumably these could have gone into Spit Vs or P-40s or even P-39s might have been better than Hurricane IIs.

The US got less than the 3,000 they were supposed to get.
The British and Canadians got almost 24,000 single stage Merlins. A lot of Merlins went to Britian to be used in British bombers.
However the timing is wrong.
Packard built 45 Merlins in 1941, they built 7,251 in 1942 and 12,292 in 1943. production of single stage Merlins dropped to 7,171 in 1944 but production of 2 stage engines was 15,798. Some of these also went to England.

Please forget about the using Merlins in P-39s nonsense. You have to change the front of the engine, Merlin built the reduction gear into part of the engine block. You also have to change the rear of the engine.

Supercharger is larger and there is more 'stuff' hanging low down. Carb is on the bottom, it either needs to be flipped or the radiator needs a new duct.

Maybe you can stretch the fuselage fit the Merlin supercharger inside?
Now how long does it take to sort out the drive shaft and gear box at the front?
10ft drive shaft turning 3000 rpm with a different vibration pattern than the Allison?

Most anything can be done if you spend enough time and money. The important question is, should you?

 

[Steamed_Banana]

The US got less than the 3,000 they were supposed to get.
The British and Canadians got almost 24,000 single stage Merlins. A lot of Merlins went to Britian to be used in British bombers.
However the timing is wrong.
Packard built 45 Merlins in 1941, they built 7,251 in 1942

Ok but if they built 7,251 in 1942 some of these could have been put in P-40s, P-51s, and / or Spitfires, right? Instead of going into various planes that never left Canada?

 

[PAT303]

The Mk 111 wing although clipped had a span of 33ft 9in compared to 32ft 2in of the MkV. Length was also greater on the Mk 111 30ft 4 in vs 29ft 11in.View attachment 878147

Had it gone into production the MkIII would have rewrote not only the Spitfire's story but the war.

 

[wuzak]

Ok but if they built 7,251 in 1942 some of these could have been put in P-40s, P-51s, and / or Spitfires, right? Instead of going into various planes that never left Canada?

I'm sure that most of the 7,251 produced in 1942 went to Britain.

Which of the planes "never left Canada"?

Hurricanes were produced in Canada during the first few years of the war.
Mosquito production in Canada started in 1942. Canadian Mosquitoes were used in the UK from 1943.

Lancaster production started in Canada in 1943.

The Lancaster B.III (same as B.I, but with Packard built engines) was in production from 1942.

 

[Shortround6]

Ok but if they built 7,251 in 1942 some of these could have been put in P-40s, P-51s, and / or Spitfires, right? Instead of going into various planes that never left Canada?

The engines that powered P-40Fs in 1942 were part of the 7,251 built.
I would also note that there were hundreds of P-40s, P-39s and other US combat aircraft that never left the US.
A number of the P-40F groups that were sent to Egypt and/or operation Torch got brand new planes for the overseas deployment and passed their first issue aircraft to new units in training.
Operational training units need at least some up-to-date operational aircraft for good training. Using older aircraft only goes so far. It is not so much having planes that are not up to standard of newest performance but that cockpits/procedures are as close to operational planes as possible.
Also the training schools were training ground crew. Having groundcrew that are at least somewhat familiar with the newest aircraft is help when trying to keep them flying in front line airfields.

Canadian Hurricane production followed a rather torturous path. Yes there were Hurricanes built and shipped without engines and propellers, later with engines but without propellers, there were times when around 50 used engines from Fairley Battles were used (pre Packard) but this covers several years so blanket statements don't apply for the entire period.
Hurricanes were shipped with Packard engines that were taken out in England and replaced by British Merlins. Not because they thought the Packards were bad but for standardization.
Packard built engines used some non-standard British accessories and fittings. However the British were glad to get the Packard engines in the Hurricanes as they provided useful spares for the Lancasters that used Packard built Merlins to start with.
Shipping parts, engines and props and instruments from Britian to Canada to be fitted to airframes being built in Canada and then shipping the complete aircraft back didn't make a lot sense.
They wound up with around 750 Fairley Battles in Canada for the Commonwealth training plan. Adding to or replacing some of those used aircraft did contribute to the war effort with better trained pilots and crews.

The US and the British did a number of things wrong in WW II. Continuing to send poorly trained men into combat was not one of them. There is a difference between poorly trained/inadequate training and green pilots/crew. Green means no combat experience even 300 hours of flight time. Low time and green means lots of casualties/losses.

Figuring out how to put Allisons into Canadian built Hurricanes to use as trainers seems like a lot more trouble than it is worth. You are not training the ground the crew/s in how to maintain/service Merlin engines.

 

[MiTasol]

Ok but if they built 7,251 in 1942 some of these could have been put in P-40s, P-51s, and / or Spitfires, right? Instead of going into various planes that never left Canada?

Like the Lancaster Mk Xs that were in combat in Europe.

 

[Engineman]

Merlin and Spitfire history is a bit more complicated.
It is also complicated by the demand for two speed engines by other aircraft, Hurricane gets the blame most of the time, but the Defiant and Halifax seem to get overlooked as do the Beaufighter and the Wellington (and the Whitley?)
Of the British factories that built Merlins, Derby built just about all versions. Derby was design headquarters and sometimes just built small numbers of some models. Crewe was the 1st satellite factory and also built most versions. Glascow and Ford came in bit later and were set up to build 2 speed engines from the start. Derby's ability to build two speed engines in large quantities is subject to question.
Both Ford and Glasgow don't start turning out finished engines until sometime in 1941. When they do, they soon are making hundreds of engines a month instead of dozen of engines like Derby. Derby is making a lot more different models per month.
The Merlin 45, 46, 47, 50, and 55 (and the XIII, 30 and 32 built in Derby) were all built by Derby and Crewe.
Most of the two stage engines were built at Derby and Crew.

Trying to maximize each factory's production with the minimum amount of re-tooling/retraining seems to have been the goal.

The Spitfire MK II is also overlooked. The Merlin XII engine was a better engine than the Merlin III with the same 9.09 supercharger gear later used on the Merlin 45 and also used pressure water/glycol cooling instead of pure glycol like the Merlin III. In the summer of 1940 it was allowed to use 9lbs of boost 'normal' with 100 octane and 12lbs boost emergency.
It was also allowed to use 9lbs while climbing and 7lbs at max cruise. Granted the BoB was pretty much over before very many had been delivered but the situation in Aug/Sept 1940 was not Spitfire Is vs Spitfire IIIs with Merlin XX engines and making Hurricanes with Merlin XII engines but was the historical Spitfire IIs vs Hurricane IIS with Merlin XX engines.
British didn't know how badly the Germans had been hurt or perhaps more accurately, they didn't know the Germans ability to sustain losses. The British needed lots of fighters and so they needed better Hurricanes to make up numbers. Germans then screwed up the British by coming out with the 109F instead of just sticking a better engine in 109E the upgraded Hurricane was no longer a good solution.
Merlin 45 had a lot more in common with the Merlin XII than it did with Merlin III.

British took a while to go higher boost levels. The Merlin 45 was introduced at the same 9lb/12lb limits as the Merlin XII but the better supercharger allowed for higher altitudes.
Later they could use 12lbs under more conditions and later they got to use 15/16lbs of boost but that was not until Jan 1942 (?)
Use of the higher boost gained around 25-30mph at around 10,000ft.
Use of a two speed engine in the Spitfire would have been very good idea in late 1940 IF the engines had been available without shorting some other aircraft production.
In 1942 they had gotten a lot better performance out of the single speed engines. A two speed would have been better, but the margin of difference would be smaller.

Hi,

To superficial latter-day study, the way that Spitfire engine development in the late 1930's and early War years progressed is intriguing. Certainly, it would appear that the initial options for 2-speed Supercharging and CS props would be obvious. But things were not so clear at the time and we must realise that development usually only progressed with official backing and to get that, Service doctrine and Air Ministry approval had to have seen and understood the validity of the requirement. Take the concept of the single-seat combat Fighter, it was not really a primary solution for RAF Bomber defence doctrine until, possibly, 1939. On top of that, the RAF Fighter tactics were awful "Formation attacks", Dogfighting and manoeuvre combat were not contemplated. Even basic VP Propellers were something strange, and the RAF had to have late-in-the-day trials to decide if they were suitable for Fighter aircraft and formation flying, the conundrum being that they had to already have aircraft/engines with them fitted to say if they were useful. The same went for the CS Prop. Also, the Biplane/Monoplane Fighter argument was hardly concluded and best not to mention the use of Float-type carburettors!
Somewhat surprisingly, the technical development was more advanced in some ways. RR had developments in hand for the 2-Speed supercharger in 1934, and this was in production as the Merlin X in 1938, which went into bombers with it's 3" longer size, 0.42 ratio propeller, versions of Whitely, Halifax, Wellington and some smaller aircraft, Horsley and prototype Spitfire III. But the Spitfire could not initially take the longer engine without development and interruption to production, even if the need was known! The Battle of Britain changed all that, but it was still impossible to interrupt production to any extent. However RR did work hard to improve the power of the Merlin that COULD be fitted into the basic Spitfire airframe, and that was the 40/50 Series Merlin with improved features and Supercharger(s) that produced the various Spitfire Mk V types. In the similar timeframe, RR also improved the Merlin X as the Merlin XX with improved features and the similar improved design of the 2-speed Supercharger. This engine could be fitted into the Hurricane, and it was.
Hooker was already developing the 2-Stage Merlin by mid 1940. The exact dates for the first consideration of the 2-Stage engine in the Spitfire is unclear to me, but I strongly suspect that the reason 2-Speed Single Stage Merlin did not appear in the Spitfire (other than development), was that, by the time the changes could be fitted-into production, they knew the 2-Stage Merlin engine was coming. Let's face it, the Mk 9 Spitfire itself was a rush job, and if extra effort developing a "2-speed Mk V Spitfire" had been made in 1941, it may have delayed the Mk 9 Spitfire development.

Cheers

Eng

 

[drgondog]

Ok but if they built 7,251 in 1942 some of these could have been put in P-40s, P-51s, and / or Spitfires, right? Instead of going into various planes that never left Canada?

The USAAF and the British had a deal with respect to the allocations of the Packard built Merlins (under license). The balance of the allocations for the Brits were essentially none of the AAF business. On the other hand Materiel Command favored the P-40F and were indisposed to installing in the P-51.

The battle at that time was the A-36 procurement and Mat.Cmd wanted nothing to do with it, and were lobbying to shut down production of Mustangs after the Mustang IA purchase completed in Nov. It was only when Military Requirements in Plans Division prevailed, the Mat.Cmd. was forced to acquire Mustangs for the AAF and that resulted in the claw-back of 58 P-51-NA from the 150 commitment of Mustang IA.

While Arnold was getting briefed during his May 1942 trip to UK on the Merlin Mustang project at R-R, NAA was getting indications from their beltway bandits in DC that both Ambassador Winant and Ass't Secy War Lovett were very favorable to the project and stated so to Arnold by letter in June 1942.

It was around this time that Mil.Req. jammed the P-51A contract as follow on to A-36 and further specified that the P-51A contract could be converted to the P-51B at any time, based on outcome of flight tests. Which they did, but Arnold approved the NA-102 P-51B-1 contract in August and the P-51A contract balance to the P-51B-5 followed quickly.

Production design and tooling for the P-51B-1 was in progress while NA-101 was undergoing the Merlin mod from the P-51-NA airframe.

There were a lot of moving parts in 1942 that essentially changed the mix of 1650-1s and the very new 1650-3 to be built. From the very beginning the Brits made it clear ~ May 1942 that they supported the Merlin Mustang conversion and pressured Materiel Command to allocate future AAF 1650-3 production commitments to North American and wind down 1650-1 production in 1943 to focus on spare engines for the P-40F/L.

BTW this chain of events was paralleled by a strong desire for NAA to deliver completed P-51B airframes for final assembly in UK where Merlins would be installed. That project died because of two year lead time to execute any possible plan - and dilute NAA resources to deliver to production commitments to AAF.

IMO, absent the actual exchange of correspondence, the narrative above explains why neither Curtiss nor Lockheed ever were considered for allocations to P-40/P-60 or P-38 projects.

As Shortround pointed out, the P-39 was never a practical destination for a multitude of reasons, and it should be pointed out that the P-63 has a stretched airframe and wing movement to enable the Allison 2S/2S with auxiliary second stage engine installed.

The timeline to deliver a flying P-51B with a functional production ready V-1650-3 could not have been compressed much due to issues with the early 1650-3. Recall that the XP-51B airframe was ready in late September, but the first of two 1650-3 delivered to NAA failed in the first week of October during engine run-up tests. The second one was delivered in mid-November and then there was a pause until May when the production deliveries began. Then there was a strike at Packard which cost June/July commitments to be far short, which caused a delay of operations in UK from late September to December 1. 1943.

 

[yulzari]

Had it gone into production the MkIII would have rewrote not only the Spitfire's story but the war.

Rewritten the Spitfire story yes. The war? It would help but not critically in the wider world.

Overall the Spitfire story is a battle between perfection and expediency. The mass numbers past the MkI/II are the MkV to get a quick improvement as the opposition became better with a quick fix of the later engine into the existing airframe. The MkIX was the same story. The MkIII and MkVIII were the ideal solutions of the period but would affect production flow and re tooling for the more altered airframes. Better but something was needed 'now' not 'in á while'.

In the background was the planned existence of replacing the Spitfire entirely by the next generation of engine and airframe. Even the Hurricane dragged on in production into 1944 until the new toys were about in enough numbers. The Spitfire clung to production until it was barely a Spitfire at all and not even using the Merlin, just to keep up with the new boys.

When you run an air force in major peer campaigns you have to have something actually in service in the numbers to equip your pilots not play Top Trump cards. Gladiators fought in the air in 1941 when they were obsolete before they were on the production line, just because they were there, not because they were good.

 

[Frog]

I am aware of that incident, but in the US perspective once converted this is designated as a "Free French" unit from my understanding, individual betrayals notwithstanding.



French Army of Liberation = Free French for the Americans, as in "on our side now" = Free French, at least informally, regardless of the previous history of each individual unit or soldier

Armée Française de la Libération was the official designation to implement the fact that there were no more distinctions between " the good Free French '' and the " bad Armée d'Afrique '' whose main fault had been to be disciplined and following orders (after the compromised cadre was purged).

De Gaulle had wisely understood after ousting his rival Giraud (that had the favor of the Americans and notably Roosevelt), that a united front was the only chance to have a France again internationally recognized as a power. And frankly, while Giraud was a great soldier (captured twice in WW 1 and WW2, he managed to escaped twice, the last time by rappelling the cliff of the Kônigstein fortress was he was interned, aged 63...), he was no more up to date to modern warfare and had not enough politic sense.

 

[ThomasP]

Hey Geoffrey Sinclair,
re

Interesting, as far as I know the mark III tests did not include fitting a Merlin 45 or 46, apart from the clipped wing the mark III included a number of detail changes, canopy, radiator, wheel fairings, ducting, retractable tail wheel, looks like it had about the same tare weight as the mark V. The changes gave it a better top speed before the engine change. Agreed it seems standard 1940/41 Spitfire propellers were in use.

Apologies, I was not clear that the performance values for the Merlin 45 & 46 were from tests of the Spitfire Mk VB. I should have written (in bold below):

Reference Spitfire Mk III to see the significant improvement in performance (predicted and found on testing) when fitted with the Merlin XX vs the standard Spitfire Mk VB with Merlin 45 & 46. . . .

Thank you for pointing out the lack of clarity. I have edited my post upthread.

 

[PAT303]

If it is either:
- A Spitfire III airframe (= cut the drag a lot)
- It has in the nose the 2-stage Merlin or the engine of similar power (=much increased power at all altitudes)
then it should beat 400 mph mark

As we know, the Spitfire V even with the best boost and best fit & finish was still under 380 mph.

The Mk III was not just about the speed but the many improvements it had over the Mk I/II and V, an important one as its improved overall handling which would have allowed it to go head to head with the 109F and later the FW190, something the Mk V couldn't, I would imagine it would have likely drawn interest in the 60 series Merlin earlier than what historically happened moving the adoption of 2 speed 2 stage engines forward and therefore eliminating the need for the interim Mk V Mk IX models.

 

[Shortround6]

The wing of the Spitfire III was shortened to 30ft 6in and area was 220sq ft.
A clipped wing V had a wingspan of 32ft 6in and 232 sq ft. Not huge but there was a difference. Just about any Spitfire wing could be converted to the "clipped" configuration by unbolting the existing wing tip and bolting on a new wing tip.
The MK III prototype (N3297) had been fitted with a normal wing by April of 1941 and kept the normal wing when fitted with the two stage engine by RR.

 

[tomo pauk]

Take the concept of the single-seat combat Fighter, it was not really a primary solution for RAF Bomber defence doctrine until, possibly, 1939.

What was the primary solution for the RAF bomber defence - if that was not the 1-seat combat fighter - in the 1930s?

On top of that, the RAF Fighter tactics were awful "Formation attacks", Dogfighting and manoeuvre combat were not contemplated.

Maneuvering abilities were the part of specification for, at least, Spitfire.

But the Spitfire could not initially take the longer engine without development and interruption to production, even if the need was known!

Two unfinished Spitfire I airframes taken from the production line became Spitfire III prototypes, together with the 2-speed engine.

The Battle of Britain changed all that, but it was still impossible to interrupt production to any extent.

Westland was being tooled up for Spitfire production from scratch. If there was a will, it should've been making the Spitfire III.

Let's face it, the Mk 9 Spitfire itself was a rush job, and if extra effort developing a "2-speed Mk V Spitfire" had been made in 1941, it may have delayed the Mk 9 Spitfire development.

The '2-speed Mk V Spitfire in 1941' kinda misses the point - there should've been the Spitfire III from the late 1940, and 'Spitfire III minus' (= powered by the Merlin 45) from early 1941.
The Mk.9 depended on the engines; the airframes were around.

My opinion is that RAF & AM allowed too many so-so or unworthy aircraft to be made, some in more than one factory (Battle, Botha), while leaving Spitfire on the most basic Merlins between mid-1940 and mid-1942, as well as relying on the pre-war legacy airframes' design instead of investing some resources and manpower to update the aerodynamics in a timely manner.
Making Hurricanes in 1943 was probably justifiable; making them in 1944 was badly wrong.

 

[Engineman]

What was the primary solution for the RAF bomber defence - if that was not the 1-seat combat fighter - in the 1930s?


Maneuvering abilities were the part of specification for, at least, Spitfire.


Two unfinished Spitfire I airframes taken from the production line became Spitfire III prototypes, together with the 2-speed engine.


Westland was being tooled up for Spitfire production from scratch. If there was a will, it should've been making the Spitfire III.


The '2-speed Mk V Spitfire in 1941' kinda misses the point - there should've been the Spitfire III from the late 1940, and 'Spitfire III minus' (= powered by the Merlin 45) from early 1941.
The Mk.9 depended on the engines; the airframes were around.

My opinion is that RAF & AM allowed too many so-so or unworthy aircraft to be made, some in more than one factory (Battle, Botha), while leaving Spitfire on the most basic Merlins between mid-1940 and mid-1942, as well as relying on the pre-war legacy airframes' design instead of investing some resources and manpower to update the aerodynamics in a timely manner.
Making Hurricanes in 1943 was probably justifiable; making them in 1944 was badly wrong.

The Turret Fighter.

The specification did include manoeuvre, I wrote about RAF doctrine and Tactics before BoB.

Prototypes and developments do not equate to production reality.

The loss of the Supermarine works in September 1940 concentrated the effort on production.

A "2-speed Mk V" would have missed the point, it would have not had the specific capabilities of the high alt and low alt versions that were actually built. Even the Mk 9 came with altitude optimised versions, so saying that a 2-speed Mk III (or "Mk V") would have been a panacea is pie in the sky.

"Unworthy aircraft" production restricting the production of an earlier/better Spitfire in 1940 is maybe more of a matter of not having clairvoyance?

Eng

 

[tomo pauk]

The Turret Fighter.

Turret fighters were a distinctive minority among the RAF fighters of the 1930s.

Prototypes and developments do not equate to production reality.

Of course.

A "2-speed Mk V" would have missed the point, it would have not had the specific capabilities of the high alt and low alt versions that were actually built.

The Spitfire III, as well as the Spit V with the 2-speed Merlin, removes a lot of the dire need to have the separate high and low altitude versions.

Even the Mk 9 came with altitude optimised versions, so saying that a 2-speed Mk III (or "Mk V") would have been a panacea is pie in the sky.

Not a panacea, but a much better thing to have, especially the Mk.III.

"Unworthy aircraft" production restricting the production of an earlier/better Spitfire in 1940 is maybe more of a matter of not having clairvoyance?

Note that I've specified the time of about two years, mid-1940 to mid-1942.

 

[Steamed_Banana]

The USAAF and the British had a deal with respect to the allocations of the Packard built Merlins (under license). The balance of the allocations for the Brits were essentially none of the AAF business. On the other hand Materiel Command favored the P-40F and were indisposed to installing in the P-51.

The irony is that the Brits wanted the P-40F/L too and never got anywhere near as many as they wanted

The battle at that time was the A-36 procurement and Mat.Cmd wanted nothing to do with it, and were lobbying to shut down production of Mustangs after the Mustang IA purchase completed in Nov. It was only when Military Requirements in Plans Division prevailed, the Mat.Cmd. was forced to acquire Mustangs for the AAF and that resulted in the claw-back of 58 P-51-NA from the 150 commitment of Mustang IA.

We are fortunate that Plans Division prevailed

While Arnold was getting briefed during his May 1942 trip to UK on the Merlin Mustang project at R-R, NAA was getting indications from their beltway bandits in DC that both Ambassador Winant and Ass't Secy War Lovett were very favorable to the project and stated so to Arnold by letter in June 1942.

It was around this time that Mil.Req. jammed the P-51A contract as follow on to A-36 and further specified that the P-51A contract could be converted to the P-51B at any time, based on outcome of flight tests. Which they did, but Arnold approved the NA-102 P-51B-1 contract in August and the P-51A contract balance to the P-51B-5 followed quickly.

Production design and tooling for the P-51B-1 was in progress while NA-101 was undergoing the Merlin mod from the P-51-NA airframe.

There were a lot of moving parts in 1942 that essentially changed the mix of 1650-1s and the very new 1650-3 to be built. From the very beginning the Brits made it clear ~ May 1942 that they supported the Merlin Mustang conversion and pressured Materiel Command to allocate future AAF 1650-3 production commitments to North American and wind down 1650-1 production in 1943 to focus on spare engines for the P-40F/L.

BTW this chain of events was paralleled by a strong desire for NAA to deliver completed P-51B airframes for final assembly in UK where Merlins would be installed. That project died because of two year lead time to execute any possible plan - and dilute NAA resources to deliver to production commitments to AAF.

IMO, absent the actual exchange of correspondence, the narrative above explains why neither Curtiss nor Lockheed ever were considered for allocations to P-40/P-60 or P-38 projects.

As Shortround pointed out, the P-39 was never a practical destination for a multitude of reasons, and it should be pointed out that the P-63 has a stretched airframe and wing movement to enable the Allison 2S/2S with auxiliary second stage engine installed.

The timeline to deliver a flying P-51B with a functional production ready V-1650-3 could not have been compressed much due to issues with the early 1650-3. Recall that the XP-51B airframe was ready in late September, but the first of two 1650-3 delivered to NAA failed in the first week of October during engine run-up tests. The second one was delivered in mid-November and then there was a pause until May when the production deliveries began. Then there was a strike at Packard which cost June/July commitments to be far short, which caused a delay of operations in UK from late September to December 1. 1943.

All very interested, and I concede the P-39 may have been impossible within the timeline. A Merlin XX or two-speed V-1710 powered Mustang "IIX" however might have filled a valuable niche during a 1 year or so window in later 1942-mid 1943 before the Mustang III / P-51B production ramped up.

 

[drgondog]

The irony is that the Brits wanted the P-40F/L too and never got anywhere near as many as they wanted

The Brits never got as many B-24s, P-40F, B-25, C-47s etc as they wanted. Had they done so, there would have remained a very small AAF core of its future self. But that is another political drama.

All very interested, and I concede the P-39 may have been impossible within the timeline. A Merlin XX or two-speed V-1710 powered Mustang "IIX" however might have filled a valuable niche during a 1 year or so window in later 1942-mid 1943 before the Mustang III / P-51B production ramped up.

It wasn't feasible to jam a Merlin in without redesigning the aft fuselage to accommodate an updraft carb - the P-63 with two stage/auxiliary two speed supercharger essentially matched the V-1650-1 with slightly higher FTH altitude - but required major mods to accomplish. It would have been very nice at Guadalcanal in late 1942 but was not operational until 1944 and nothing I have seen could have compressed that timeline.

It wasn't feasible to install the V-1710-119 or equivalent into a P-51 or P-51B airframe and still call it a P-51. The XP-51J had zero parts/tools compatibility with the P-51B/D. It was longer fore and aft of the firewall bulkhead, the wing was moved back, the lower longeron attach locations were 5" further aft of the firewall, etc, etc.

 

[Steamed_Banana]

The engines that powered P-40Fs in 1942 were part of the 7,251 built.

I'm well aware

I would also note that there were hundreds of P-40s, P-39s and other US combat aircraft that never left the US.

Well aware of that too

A number of the P-40F groups that were sent to Egypt and/or operation Torch got brand new planes for the overseas deployment and passed their first issue aircraft to new units in training.
Operational training units need at least some up-to-date operational aircraft for good training. Using older aircraft only goes so far. It is not so much having planes that are not up to standard of newest performance but that cockpits/procedures are as close to operational planes as possible.
Also the training schools were training ground crew. Having groundcrew that are at least somewhat familiar with the newest aircraft is help when trying to keep them flying in front line airfields.

Agree with all of this, 100% though I think given the shortage of V-1650-1, they did not need the Merlin types for general pilot training in the US. P-40N for example worked fine in this role and was in fact the most common type used for it.

Canadian Hurricane production followed a rather torturous path. Yes there were Hurricanes built and shipped without engines and propellers, later with engines but without propellers, there were times when around 50 used engines from Fairley Battles were used (pre Packard) but this covers several years so blanket statements don't apply for the entire period.
Hurricanes were shipped with Packard engines that were taken out in England and replaced by British Merlins. Not because they thought the Packards were bad but for standardization.
Packard built engines used some non-standard British accessories and fittings. However the British were glad to get the Packard engines in the Hurricanes as they provided useful spares for the Lancasters that used Packard built Merlins to start with.

Thanks, this is partly what i was referring to about the Canadian Packard Merlins not being used in combat. IIRC this was also the case with some of the Mosquitos and maybe some Lancasters too, it was a while ago when I read a long article on the subject. Standardization makes some sense. But I'm not sure it was a good use of the badly needed V-1650-1s under the circumstances.

Shipping parts, engines and props and instruments from Britian to Canada to be fitted to airframes being built in Canada and then shipping the complete aircraft back didn't make a lot sense.
They wound up with around 750 Fairley Battles in Canada for the Commonwealth training plan. Adding to or replacing some of those used aircraft did contribute to the war effort with better trained pilots and crews.

The US and the British did a number of things wrong in WW II. Continuing to send poorly trained men into combat was not one of them. There is a difference between poorly trained/inadequate training and green pilots/crew. Green means no combat experience even 300 hours of flight time. Low time and green means lots of casualties/losses.

Again, I agree wholeheartedly, and training on type (or even, for example, putting in enough hours on aircraft with retractable landing gear) was a MAJOR issue early in the war for the US and RAAF in the Pacific in particular. But I don't think Packard Merlins were best used for this. AT-6 etc. was sufficient for a lot of it and as I mentioned, P-40Ns or other Allison P-40 types, as well as older somewhat clapped out Hurricanes and Spitfires could have helped a lot with this role.

Figuring out how to put Allisons into Canadian built Hurricanes to use as trainers seems like a lot more trouble than it is worth. You are not training the ground the crew/s in how to maintain/service Merlin engines.

That does sound a bit complicated, granted. On the other hand, another 2 - 3,000 Merlin XX powered Allied fighters in 1942-43 could have really helped the war effort on the front lines IMO.

 

[Steamed_Banana]

The Brits never got as many B-24s, P-40F, B-25, C-47s etc as they wanted. Had they done so, there would have remained a very small AAF core of its future self. But that is another political drama.

Or Wildcats / Martlets, or Avengers, or Corsairs or Hellcats (at least, on an early enough timeline so to speak)

It wasn't feasible to jam a Merlin in without redesigning the aft fuselage to accommodate an updraft carb - the P-63 with two stage/auxiliary two speed supercharger essentially matched the V-1650-1 with slightly higher FTH altitude - but required major mods to accomplish. It would have been very nice at Guadalcanal in late 1942 but was not operational until 1944 and nothing I have seen could have compressed that timeline.

I get that, I already conceded a couple of times to drop the proposal of the P-39X I kinda feel like I stepped in something when I made that comment and now it won't come off my shoe...

It wasn't feasible to install the V-1710-119 or equivalent into a P-51 or P-51B airframe and still call it a P-51. The XP-51J had zero parts/tools compatibility with the P-51B/D. It was longer fore and aft of the firewall bulkhead, the wing was moved back, the lower longeron attach locations were 5" further aft of the firewall, etc, etc.

Yeah but how about a V-1650-1 (or theoretical V-1710 equivalent) into a P-51 / P-51A