Mustang Mk IA Photo

[MIflyer]

Here is another one of those photos that pop up. It shows Mustang Mk IA airplanes, the company designation being NA-91, that must be shown at the NAA plant at Inglewood, since they are still being assembled. They were fitted with four 20MM cannon. Only 150 NA-91's were built, and 93 went to the RAF with 55 going to the USAAF, being fitted with cameras and designated F-6A. The last two NA-91's off the production line were converted with V-1650-3 engines to create two XP-51B's.

Note that some of the NA-91's are in OD while others are in RAF brown and green camo but with US markings. Some of these served in the Med.

Also note that the NA-91 in the foreground has the early clamshell style radiator intake. I wonder if that was in fact an early Mk 1 modified to test the 20MM installation.

.

 

[CORSNING]

Mlflyer,
Great picture sir. I believe the P-51 headed to the USAAF are
painted Dark Green at this time. I think the P-51A was the first
variant to receive the OD over Dark Gray.
Hey you modelers out there, fill us in please.

 

[MIflyer]

Good question!

And when the F-6A's went to war in the Western desert, they probably were painted something else entirely.
The WWII vintage film, "A Day with the A-36's" shows that the Apache unit had acquired a few NA-91's as well.

By the way, I understand that the RAF sent no Mustang Mk I's to the Med and sorely missed the capability for long range low altitude recon, The borrowed a couple of A-36A's from the USAAF for recon, and provided them with Spitfire escort, but that plan fell through when the Spits could not keep up with the Apaches at normal cruise speeds.

 

[fubar57]

I have the A-36 cruising at 400km/h, the Spitfire Mk.Vc at 518km/h and the Spitfire Mk.IX at 521km/h. Those that know this sort of thing can accurately adjust

 

[MIflyer]

But what can the Spitfire V cruise at and get the same range as the A-36A?

 

[fubar57]

I was just going with the "couldn't keep up" part

 

[wuzak]

Also note that the NA-91 in the foreground has the early clamshell style radiator intake..

Didn't all P-51s/Mustangs with the Allison V-1710 use teh same radiator intake?

The radiator intake of the Allison models was adjustable.

With the increased power the Merlin gave, especially at higher altitudes, the radiator system had to comprehensively redesigned.

 

[MIflyer]

They changed the radiator scoop on the later Allison models, the A-36A and the P-51A. I thought the change had occurred earlier, with the Mk IA, but it appears the Mk 1 and IA both had the moveable front airscoop. The attached drawing is from the In Action book.

 

[BiffF15]

Thanks gents I learned something new today!

Cheers,
Biff

 

[MIflyer]

Here's another nice Mustang Mk 1 photo. I think it is supposed to be a Mustang deployed to a forward airfield in France after D-day - but I do not see any invasion stripes so I rather doubt that to be the case.

Mustang

 

[Gnomey]

Cool shots!

 

[XBe02Drvr]

The borrowed a couple of A-36A's from the USAAF for recon, and provided them with Spitfire escort, but that plan fell through when the Spitfires couldn't keep up with the A36A's cruise speed.

I have the A-36 cruising at 400km/h, the Spitfire Mk.Vc at 518km/h and the Spitfire Mk.IX at 521km/h. Th

But what can the Spitfire V cruise at and get the same range as the A-36A?

I was just going with the "couldn't keep up" part

Oftentimes the "efficiency curve" around best range airspeed can be rather steep, and the fuel penalties for cruising at a different speed rather high.
Back in the day the RA5C's best range airspeed was 25-30 knots higher than the F4J, though they had the same engines and the Vige was nearly 20K pounds heavier. This made escorted recon missions over the north problematical. And at "feet dry" ingress and egress speeds, the F4 had to go to min burner to stay with a Vige running at full military. This meant the tankers usually had to hang out uncomfortably close to Indian country.
I can't imagine a Spit with its limited tankage being a practical escort for a Mustang on a long range recce. Especially at high speed, where the Spit's drag rise would be significantly higher then the pony's. It's all about cooling drag.
Cheers,
Wes

 

[MIflyer]

Yes, the Spit would have to slow down to the Mustang's long range cruise speed - given its limited range it could not afford to S-turn around the Mustang. I suspect that when you pull the Spit's power back to stay with the Mustang you end up with operating inefficiently. The Mustang airframe was more efficient than the Spit, which explains why with the same Merlin 61 engine the P-51 was 30 mph faster. They said that the Allison could be throttled back to to a nice lazy cruise in a way that the Melrin could not handle.

And an A-36's engine was set up for max performance at 5000 ft. A Spit V would be out of its element down there.

An A-36 could haul two 500 lb bombs over a range of 550 miles. A fighter bomber Spit IX with two 500 lb bombs had a effective combat radius of 95 miles.

In the CBI after they got some late model fighters into the theater they tried escorting F-4's on recon missions using P-38's. Did not work! Shorn of the guns, a recon Lightnng could cruise at a speed that P-38 fighters could not handle.

 

[ColFord]

The photo of a RAF Mustang Mk.I is of an aircraft of No.26 Squadron RAF and dates from April 1945 when the Squadron had re-equipped with Mustang Mk.I aircraft and was based in France, spotting for units of the French Navy bombarding pockets - holdouts - of German resistance in French ports. As this photo was taken well after the timeframe when 2TAF had finally removed the last vestiges of the D-Day distinctive markings, and most of the aircraft No.26 Squadron re-equipped with had come out of MUs following major refurbishment and services, they were generally of a relatively clean appearance. There are a number of photos of the Mustang Mk.I aircraft of No.26 Squadron RAF that were taken when an official RAF photographer visited them during April 1945 whilst they were on their naval gunfire spotting task. Below 5,000 ft a Spitfire V and even a Spitfire IX would have difficulty keeping up with an RAF Mustang Mk.I, Mk.IA or Mk.II in level flight as the engines and in particular, the superchargers had been optimised for performance from 0 feet up to around 10,000ft with the best performance below 5,000ft. In the normal maximum throttle, without going to overboost, they could pull away from a Spitfire V or IX. Above 5,000ft the equation started to change, by 10,000ft the Mustang was "getting out of breath" and by 15,000ft, well and truly "running out of puff" and the Spitfires would be pulling away and climbing as well, especially the Spitfire IX. The RAF and RCAF Tac/R units in 2TAF that re-equipped with Spitfire FR.IXs, had to change their operational procedures and tactics to take account for the different performance of the Spitfire FR.IX, in particular they found that they spent much more time keeping one eye on the fuel guage, their sorties were conducted at a higher altitude and as a consequence had to use longer focal length lenses on their recce cameras, and the taskings they were given did not penetrate far beyond the immediate frontline area.

 

[MIflyer]

Very interesting! According to Wikipedia, 26 Sqdrn traded in their Lysanders for Mustank MK1's early in the war, then switched to Spits, and then came back to Mustangs later. And it appears the ships that were providing the firepower were Free French.

The RAF kept operating Allison Mustangs to the end of the war. The last known kill by a Allison Mustang was on 1 Jan 1945, when one shot down a Ju88 that was one of the lead aircraft of Operation Bodenplate. I think the operational Allison Mustangs were all phased out by the USAAF before the end of the war.

I found an interesting photo that shows that the "razorback" P-51B/C Mustangs were used by the USAAF to the end of the war and for a time after. Must have been pilot preference. An A-36A pilot said that we were scrapping brand new P-51D's before the war ended in the ETO.

 

[ColFord]

Never believe everything that is in Wikipedia. No.26 Squadron RAF transitioned from Westland Lysanders to Curtiss Tomahawks, then onto N.A. Mustang Mk.Is.

Last operational use RAF Mustang, a Mustang Mk.II was reluctantly flown back to the UK from occupied Germany in late August 1945, the Squadron and the Wing wanted to keep their Allison Mustangs a bit longer due to their range and capabilities for which they had no direct available replacement at the time. But the push for post-War standardisation and downsizing of the RAF was in full swing. So Spitfire PR.XIXs and Spitfire FR.XIVes it was to be for the next few years.

The last 'confirmed' kill, which was a 'shared' kill by F/L J Lyke and F/L A Mercer of No.268 Squadron RAF of a Ju-88G-6 night fighter being used as a pathfinder/navigation leader for a large formation of FW-190s as a part of Operation Bodenplatte on 1 January 1945. More recent research and cross referencing with Luftwaffe loss records indicates that there could be two additional air to air combat claims by Allison engined Mustangs of No.268 Squadron dating to late February 1945 that were at the time recorded as 'probables' or were noted in the pilot's log books as "Later confirmed" could add to the score beyond January 1, 1945.

A number of pilot's preferred the handling and balance of the P-51B/C over the P-51D. Fitted with a Malcolm Hood, the visibility was good, it was lighter, turned and rolled slightly better. A number of the current warbird display pilots who have flown both the P-51B/C and the P-51D have stated that they prefer the P-51B/C as a display aircraft.

 

[tomo pauk]

...
Below 5,000 ft a Spitfire V and even a Spitfire IX would have difficulty keeping up with an RAF Mustang Mk.I, Mk.IA or Mk.II in level flight as the engines and in particular, the superchargers had been optimised for performance from 0 feet up to around 10,000ft with the best performance below 5,000ft. In the normal maximum throttle, without going to overboost, they could pull away from a Spitfire V or IX. Above 5,000ft the equation started to change, by 10,000ft the Mustang was "getting out of breath" and by 15,000ft, well and truly "running out of puff" and the Spitfires would be pulling away and climbing as well, especially the Spitfire IX.
...

The low-level supercharger of the V-1710 as installed on Mustang I to II was more of a bug, rather than a feature. Reason to why Mustang I was able to pull away from Spitfires under 10000 ft was the low drag of the Mustang, not some great power developed by V-1710s (even though it could make it).
The Mustang II, whether in RAF or USAAF service, will not get out of breath by 15000 ft, let alone at 10000 ft.

 

[Milosh]

The Junker shot down was a Ju88 WNr 714277 G9+AC from 5./NJG 1 at ~09:15 north east of Barneveld

F/L Lyke claimed a Fw190 damaged at ~10:00 near Eindoven. A Fw190A-8/R2 was lost in this area.

 

[ColFord]

The low-level supercharger of the V-1710 as installed on Mustang I to II was more of a bug, rather than a feature. Reason to why Mustang I was able to pull away from Spitfires under 10000 ft was the low drag of the Mustang, not some great power developed by V-1710s (even though it could make it).
The Mustang II, whether in RAF or USAAF service, will not get out of breath by 15000 ft, let alone at 10000 ft.

I beg to differ. The RAF put in place specific modifications to the supercharger and other engine modifications to the Allison V-1710 engines installed in their Mustang Mk.I, Mk.IA and Mk.II aircraft. The RAF through those modifications optimised the engines efficiency for low level work below 10,000 ft with optimum performance below 5,000ft. Back to back service testing by the RAF of Allison engined Mustangs with the standard engine and the engine with their set of modification to improve its low level performance, showed the increase in power and airspeed attained within the altitude range they were interested in for the low level operations of the Mustangs. It also showed the dramatic drop off in the power developed by the modified engines at 10,000ft and altitudes above that. Having researched this matter, interviewed and corresponded with many RAF and Commonwealth Air Force pilots who flew Allison engined Mustangs on an almost daily basis on operations between 1942 and 1945, and who in some instances were involved in the development and testing of RAF modifications to the Allison engined Mustangs, it was the RAF specific engine modifications, combined with the airframe that gave the low level performance. The RAF also operated their Allison engines at low level with levels of boost that the USAAF on receiving the initial reports from the UK did not accept and were sceptical about. The RAF engine modifications were able to produce and sustain these high levels of boost for relatively long periods, without significant long term impact on the overall service life and maintenance requirements for the engine. It took some time before the USAAF and engineers from Allison were able to accept the performance and service life figures the RAF was getting from the Allison V-1710 engines with the RAF specific set of service modifications.

 

[tomo pauk]

I beg to differ. The RAF put in place specific modifications to the supercharger and other engine modifications to the Allison V-1710 engines installed in their Mustang Mk.I, Mk.IA and Mk.II aircraft. The RAF through those modifications optimised the engines efficiency for low level work below 10,000 ft with optimum performance below 5,000ft.

The V-1710's ability to use much more boost than originally envisioned was a feature of engine itself, not the mods designed by RAF or other users, like the AVG, RAF and RAAF did on their P-40s. With that said, I'll welcome any information, well-source off course, that will specify the exact modifications to the supercharger and other engine modificationsto the V-1710 that were conceived by the RAF.

Back to back service testing by the RAF of Allison engined Mustangs with the standard engine and the engine with their set of modification to improve its low level performance, showed the increase in power and airspeed attained within the altitude range they were interested in for the low level operations of the Mustangs. It also showed the dramatic drop off in the power developed by the modified engines at 10,000ft and altitudes above that. Having researched this matter, interviewed and corresponded with many RAF and Commonwealth Air Force pilots who flew Allison engined Mustangs on an almost daily basis on operations between 1942 and 1945, and who in some instances were involved in the development and testing of RAF modifications to the Allison engined Mustangs, it was the RAF specific engine modifications, combined with the airframe that gave the low level performance. The RAF also operated their Allison engines at low level with levels of boost that the USAAF on receiving the initial reports from the UK did not accept and were sceptical about. The RAF engine modifications were able to produce and sustain these high levels of boost for relatively long periods, without significant long term impact on the overall service life and maintenance requirements for the engine. It took some time before the USAAF and engineers from Allison were able to accept the performance and service life figures the RAF was getting from the Allison V-1710 engines with the RAF specific set of service modifications.

As above - I'll welcome the test reports that prove that RAF-conceived mods improved low-alt power, while decesased hi-alt power. There is no miracle that USAAF and Allison were sceptical to over-boosting the V-1710 - RAF was in war for more than two years before US entered the war, and they were no strangers to overboosting. The WER meant 'war emergency rating', after all.
I'll also welcome the evidence that RAF's engine modifications were used by Allison and USAAF.