WW2: Why was the 9th Air Force given P51 ins6tead of giving them to the 8th Air Force in 1943? (3 Viewers)

[Intrafinesse]

The 8th Air Force needed long range escorts, and the 9th Air Force could have used the P47 in a tactical role instead.
By 1943 I think the P51s had, or were getting, the Rolls Royce Merlin engine. By June 1943 would it not have made sense to send all P51 to the 8th rather than give some to the 9th?

 

[Greg Boeser]

The Fighter Groups assigned to the 9th were slated for low level tactical operations. The aircraft available for that as they were being formed were the P-40 and Allison engined P-51. Neither possessed the high altitude or range capability needed for escorting bombers to Germany at 25-30,000'. The Merlin Mustang changed that equation, but it was quicker to transition the groups already training on P-51s to the newer aircraft than converting groups training on P-47s. Once in England the two air forces recognized the suitability of the Merlin Mustang P-51B/C for long range, high altitude escort and arranged to loan the Mustang groups to the Eighth.
In a similar vein, the Eighth divested itself of it's four groups of B-26s to focus on long range, high altitude bombing.

 

[SaparotRob]

Good question, though.

 

[SaparotRob]

Greg Boeser Hey Greg, as long as you are here, do you know the French word for the "V" in the "CV" designation for aircraft carriers?
I don't want to rely on Wikipedia so much.
A mind is a terrible thing to lose.

 

[Greg Boeser]

Do I look like I speak French?
CV is the US Navy designator for an aircraft carrier.
The C is for cruiser, the V is for heavier than air aircraft. The first carriers commisioned were built on cruiser hulls banned by the post WWI naval treaties.
French is probably something like le portmanteau de avions.

 

[EwenS]

Greg Boeser Hey Greg, as long as you are here, do you know the French word for the "V" in the "CV" designation for aircraft carriers?
I don't want to rely on Wikipedia so much.
A mind is a terrible thing to lose.

The French designation for their carriers is "Porte-Avions". Hence the use of the "PA" usually followed by a year number in their designs that never got built. Helicopter carriers or "Porte-Helicopteres" carry "PH" designations.

Earlier this year they announced that their next carrier the "Porte-Avions de Nouvelle Generation", or PANG for short, would be named "France Libre".

 

[drgondog]

The 8th Air Force needed long range escorts, and the 9th Air Force could have used the P47 in a tactical role instead.
By 1943 I think the P51s had, or were getting, the Rolls Royce Merlin engine. By June 1943 would it not have made sense to send all P51 to the 8th rather than give some to the 9th?

General Gordon Saville was CG and Chief, Air Defense on Arnold's staff at Hq. He was also the near ultimate authority on which role each fighter would play and where to send them. He was Not a fan of the Mustang and tried to give the P-51A to the French Air Force in MTO.

He was over ruled by Plans Operational Requirements and directed the P-51A to tactical role to replace the A-36. When the Merlin based P-51B arrived he tasked them in same role to 9th AF to replace the P-39 equipped FG destined for Operation Overlord. This was during the period (late spring/Summer 1943) when both Eaker and Lovett were appealing to Arnold for both the P-38/P-51B as long range escort.

Arnold directed Saville to prioritize the P-51B for ETO and appealed to Portal to return Mustang III to SSF-ETO. Eaker at first naïvely believed it would make no difference whether 8th or 9th AF as he believed he would have control of P-51B equipped FG for 8th AF escort in the Operation Argument. He was wrong, Air Marshal Sir Leigh-Mallory (2TAC) and Brereton 9th AF wanted to control them and the 357th and 363rd coming to the ETO in fall 1943.

It took Spaatz, Portal, Arnold to sort it out. Following that conversation it was agreed that 9th FC including the 357/363FG plus all P-47D equipped FG would be subordinate to 8th AF controls through mid-May 1944. In addition the 8th AF traded 358FG (P-47s) for 357FG (P-51B) in January 1944. Portal did return a block of Mustang III/P-51B-5 to AAF in December, 1943.

 

[Frog]

The French designation for their carriers is "Porte-Avions". Hence the use of the "PA" usually followed by a year number in their designs that never got built. Helicopter carriers or "Porte-Helicopteres" carry "PH" designations.

Earlier this year they announced that their next carrier the "Porte-Avions de Nouvelle Generation", or PANG for short, would be named "France Libre".

The Mistral class Landing Helicopter Dock Ships, or Porte Hélicoptères Amphibie in French, are designated PHA (Mistral L9013, Tonnerre L9014 and Dixmude L9015) .

 

[Sabrejet]

*P-51

 

[Gardnerpilot]

The 8th Air Force needed long range escorts, and the 9th Air Force could have used the P47 in a tactical role instead.
By 1943 I think the P51s had, or were getting, the Rolls Royce Merlin engine. By June 1943 would it not have made sense to send all P51 to the 8th rather than give some to the 9th?

To be fair, All P-51 B,C,Ds left the North American Aviation factories with Packard Merlins which were not Rolls Royce Merlins. Packard redesigned the engine and it was built under license, but different in many ways. 1/3 of all Merlins were produced by Packard.

 

[MIflyer]

The Fighter Groups assigned to the 9th were slated for low level tactical operations.

And note that is where they went in the RAF, which had been operating Mustangs in tactical roles for years.

 

[MIflyer]

To be fair, All P-51 B,C,Ds left the North American Aviation factories with Packard Merlins which were not Rolls Royce Merlins. Packard redesigned the engine and it was built under license, but different in many ways. 1/3 of all Merlins were produced by Packard.

But "real" RR Merlins were sometimes used in USAAF P-51's. One of my college professors said the P-51 he flew had a RR engine and that they were much smoother than the Packard Merlins because it was a RR practice to sort through the available pistons and select ones that were as close as they could get to the same weight, leading to lower vibration.

The Packard built Merlins were different in numerous ways from the RR version, both due to a need to adapt the design for true mass production and to make some improvements that RR had not gotten around to doing yet.

Spitfire Mk XVI usually had Packard built Merlins.

 

[Dana Bell]

The real authority for P-51 assignments may be a more confused issue. In truth, when first sent to England, all the Mustangs were sent to the Eighth - the Ninth was still in the MTO and about to disband. When Eisenhower moved to the UK to begin planning Overlord, he was disappointed in the Eighth's strategic emphasis and lack of tactical training. Following the British example, the AAF needed a wholly tactical air force and the Ninth was reformed in the UK - IIRC in November 1943. Eaker took the top spot in the MTO, Spaatz and Doolittle moved to England, and the Mustangs began to be reassigned. At the same time the Twelfth became the MTO's tactical air force and the Fifteenth was created for strategic purposes. So I wonder who really made the final decisions on unit and equipment assignments.

Cheers,



Dana

 

[R Leonard]

Greg Boeser Hey Greg, as long as you are here, do you know the French word for the "V" in the "CV" designation for aircraft carriers?
I don't want to rely on Wikipedia so much.
A mind is a terrible thing to lose.

Obviously, the C in CV originally stood for cruiser as carriers were envisioned as part of the fleet scouting force. Couldn't use CA as in cruiser-aircraft because CA was already taken by the heavy cruiser types. So, what to do . . . well the Navy was looking at two methods for getting people into the air, lighter-than-air (dirigibles, blimps, and such) and heavier-than-air (the airplane). With General Order 541, issued in 1920, the lighter-than-air type craft were assigned the letter Z (so you see that as both squadron designators and as airship type designators – the Z referenced back to either Zeppelin as a type of craft or to Count Zeppelin himself) and the heavier-than-air organization received the letter V (squadron designators and aircraft types all starting with the letter V).

The true origin of the V for heavier-than-air is clouded in the mists of time and lack of documentation, but the general consensus, even in the Navy, is that the V derives from the French verb "voler," meaning "to fly" or, also from the French, "vol plane" meaning "gliding flight". Thus, you see starting with the letter V all the various stripes of heavier-than-air aircraft, squadrons designations, and finally in describing the carriers as CV, tenders as AV, AVP. AVD, and such. The carriers carried heavier-than-air V types, thus were carrier-heavier-than-air . . . CV.

 

[Frog]

Continental produced 897 Merlin V1650-7 all earmarked for P-51s.

 

[GregP]

The 9th AF got P-51s instead of the 8th AF beause General Henry "Hap" Arnold decided that was the way way to go, and HE was in command. There was nobody that could be "appealed to" or persuaded differently.

In the Military, orders are issued and followed. Any debate happens BEFORE the order. After that, there is no debate, it gets carried out.

 

[SaparotRob]

Obviously, the C in CV originally stood for cruiser as carriers were envisioned as part of the fleet scouting force. Couldn't use CA as in cruiser-aircraft because CA was already taken by the heavy cruiser types. So, what to do . . . well the Navy was looking at two methods for getting people into the air, lighter-than-air (dirigibles, blimps, and such) and heavier-than-air (the airplane). With General Order 541, issued in 1920, the lighter-than-air type craft were assigned the letter Z (so you see that as both squadron designators and as airship type designators – the Z referenced back to either Zeppelin as a type of craft or to Count Zeppelin himself) and the heavier-than-air organization received the letter V (squadron designators and aircraft types all starting with the letter V).

The true origin of the V for heavier-than-air is clouded in the mists of time and lack of documentation, but the general consensus, even in the Navy, is that the V derives from the French verb "voler," meaning "to fly" or, also from the French, "vol plane" meaning "gliding flight". Thus, you see starting with the letter V all the various stripes of heavier-than-air aircraft, squadrons designations, and finally in describing the carriers as CV, tenders as AV, AVP. AVD, and such. The carriers carried heavier-than-air V types, thus were carrier-heavier-than-air . . . CV.

Imagine my embarrassment at realizing I totally forgot about Goodyear-Zeppelins and blimps.
Some Zeppelinophile I am.
Great post.

 

[SaparotRob]

But "real" RR Merlins were sometimes used in USAAF P-51's. One of my college professors said the P-51 he flew had a RR engine and that they were much smoother than the Packard Merlins because it was a RR practice to sort through the available pistons and select ones that were as close as they could get to the same weight, leading to lower vibration.

The Packard built Merlins were different in numerous ways from the RR version, both due to a need to adapt the design for true mass production and to make some improvements that RR had not gotten around to doing yet.

Spitfire Mk XVI usually had Packard built Merlins.

AIUI externally, the RR and Packard Merlins were interchangeable. The differences were internal and varied between RR and Packard engines. One could swap engines between a Spitfire and a Mustang. One could not overhaul a Packard engine with an RR rebuild kit from Pep Boys.

 

[ColFord]

AIUI externally, the RR and Packard Merlins were interchangeable. The differences were internal and varied between RR and Packard engines. One could swap engines between a Spitfire and a Mustang. One could not overhaul a Packard engine with an RR rebuild kit from Pep Boys.

They were not. There were a number of changes internally and externally, which required the swap out and replacement of a number of ancillary items if you wanted to change from a R-R Merlin to a Packard Merlin or vice versa. Hence, why the Air Ministry and RAF in their wisdom created a separate designation - Spitfire XVI - for the variant of the Spitfire IX powered by the Packard Merlin 266 rather than the Roll-Royce Merlin and ensured all aircraft within a Squadron were all of the same sub-type IX or XVI. They had separate AM issued Pilot's Manuals which in part for the XVI described the differences in the operation of the engine and a number of the engine related ancillaries compared to the IX. Also all the ground crews on Squadron's equipped with the Spitfire XVI had to undergo specific training on the differences with the Packard built Merlin, and also ensured the supply chain for parts and maintenance tools directed the correct parts and tools to units depending on the version of Merlin fitted.

Similar for Lancasters fitted with Packard Merlins vs R-R Merlins. Different AM Pilot's Notes for the Packard Merlin engined sub-variants, concentration of aircraft in squadrons and also on bases. When the Canadian Lancaster did its visit to the UK some years ago and had an engine problem, they couldn't just 'slap a spare BBMF R-R Merlin on it' as it took longer to sort out all the engine peripherals to make a R-R Merlin work on it as an interim measure so they could complete some of the key commitments in the UK, until they could get a Packard Merlin of the right type for it to make the return flight to Canada at the end of the UK tour. At the time there was a lot of online commentary about why was it taking so long for the BBMF spare to be fitted to it, but the BBMF and Canadian technical people provided some very clear statements about the degree of work to make the BBMF R-R Merlin 'spare' fit and be usable on the Canadian Lancaster which was configured for the Packard Merlin.

Also why the CAC built Mustangs that used the 'recycled' Spitfire VIII R-R Merlin engines, were designated as a different sub-mark of CAC Mustang and required a bit of work by CAC to do all the adaption work to allow the use of the R-R built Merlin in that particular batch of CAC built Mustangs rather than US supplied Packard Merlins (especially by then Lend Lease had finished and to purchase extra engines from the US would have prohibitive in the economy of that time).

If a WW2 USAAF P-51 had a R-R Merlin fitted, it would have been a very rare occurrence, as it meant that aircraft was then outside the normal support and supply chains set up for the USAAF P-51 units.

 

[Geoffrey Sinclair]

From Air 40/1096 Statistical Summary of 9th Air Force Operations 16 Oct 1943 to 8 May 1945

MTO operations, B-24 June 1942 to September 1943, B-25 August 1942 to August 1943, P-40 September 1942 to August 1943, plus 316th Troop Carrier Group November 1942 to September 1943.

The departure left the 12th Air Force, North West African Strategic Air Force, North West African Tactical Air Force, North West African Coastal Air Force having USAAF combat units.

When the 15th Air Force was formed on 1 November 1943 it had 4 B-17 and 2 B-24 groups, plus 3 B-26 and 1 B-25 groups, the medium bomber groups left end January 1944, as part of the changes that would see the USAAF in the MTO become only the 12th and 15th Air Forces.

9th Air Force declared operational in England on 16 October 1943, taking the B-26 and troop carrier groups from the 8th Air Force.

During 1943 the Overlord commander was assumed to be either Sir Alan Brooke, or George C. Marshall. To give an idea of the situation when the Washington rumour mill heard Marshall was maybe to be appointed to Overlord it was suggested this was because Marshall had fallen foul of FDR and/or Churchill and/or Harry Hopkins, it was a demotion. The decision was made after the Tehran conference, where Stalin had not been pleased Overlord lacked a commander.

Eisenhower officially took command on 7 December 1943 and while he arrived in England in the middle of January 1944 it was another month before the formal directive from the Combined Chiefs was issued to him, since the US and UK were still discussing terms. Meantime the Mediterranean command team settled in and began recasting tactics and plans, most notably Overlord from 3 to 5 beaches. COSSAC had been too junior to ask for what it decided was needed, instead having to work with what it was allocated, the mixture of landing craft promised "bore little of or no relation as to numbers and types to the actual requirements of the proposed operation".

Leigh-Mallory was appointed Allied Expeditionary Air Force commander at the August 1943 Quebec conference, it became public in September, the unit was to be the 2nd Tactical Air force and an American equivalent. no decision made on the heavy bomber forces yet

Early arriving P-51 groups,
339th FG, designated Fighter Bomber Group in August 1943, using P-39 in US
354th FG, using P-39 in US, stayed with 9th Air Force.
357th FG (transfer from 9th), using P-39 in US.
363rd FG, using P-39 in US, stayed with 9th Air Force.

While lots of things would be nice to end June 1943 a total of 22 Merlin Mustangs had been accepted, 91 in July, 170 in August, however deliveries to the USAAF to end June were 15, then 36 in July and 137 in August, deliveries for the RAF were 22 in July and 52 in August. Meaning the USAAF had enough P-51 end August to fully equip 2 fighter groups except many would be held as attrition replacements in the US or be in the process of being shipped to Britain, the British note 3 Mustang III imports for the RAF in September and 74 in October 1943.

According to the USAAF Statistical Digest P-51 began arriving in Britain in September 1943, with 34 by the end of the month.