RAF P-51H Mustang

[Ed Russell]

This is borderline WW2 but seems to fit best here. The P-51H apparently arose from a RAF specification for an aircraft that could

roll with the Focke-Wulf 190 and also take on the Mitsubishi Zero in the Pacific, as well as an extended range Mustang. But, by the time the P-51H went into production (1946), the war was over and the RAF had no interest in the airplane.

There have been a few profiles and kits of an RAF camouflaged P-51H  KN987. No reviews I have seen have commented on the authenticity of this scheme. However one article about P-51H variants essentially concluded that these profiles and kits were fictitious.

A single example was allocated to the RAF (serial no. KN987) and rumored to have been painted in Olive Drab and Dark Green over Neutral Gray, but records show that it never went overseas and the airplane was eventually flown to McDill Field in Florida to await it’s disposition. There is currently a P-51H warbird painted in similar markings, but I believe these markings were conceptualized and not actually applied to the single RAF aircraft

 

So, was it "evaluated at Boscombe Down" as is usually stated? if so, there would be a picture somewhere. Is there such a picture?

 

Quotes from here

https://www.ipms-houston.org/wp-content/uploads/2020/04/P-51H_Mustang_Kits.pdf

[Phil Evans]

Hi Ed,

 

There is no mention of it in The Secret Years by Tim Mason, but Boscombe Down did get a P-51F which was going to be the Mustang V.

 

Hope this is of some use

 

Phil

 

 

[Nigel Bunker]

The only picture I can find is in "The Secret Years: Flight testing at Boscombe Down 1939-1945" by Tim Mason which shows an XP-51F FR409 in three colour camouflage (I am guessing Dark Green, Ocean Grey & Medium Sea Grey as it is a B&W photograph). No mention of a P-51H.

 

Beaten by Phil - oh well.

[Ed Russell]

I should have said that, after being asked this question by a colleague, I did look through The Secret Years without success.

[Graham Boak]

The usual description of the P-51H is related to the US strength standards used on versions to the D, thought to produce a heavier structure than the equivalent British standards.  Hence the experimental F and G models, with the H being a "productionised" version from this development line.  It is interesting to see the H mentioned as being designed to specifically British request, but it is not something I've seen elsewhere, and the USAAF adoption of it would seem to imply American interest from an early stage.

[SteveBrooking]

Hi

 

I have a friend in Canada who has spent many hours of his life trying to track down a photo of KN987.

 

As far as I can tell the work on the lightweight Mustangs that lead to the P-51H began in 1942 around the same time as the work in America and Britain to put a Merlin engine in the P-51 airframe. Once that initiative began it was quickly apparent that the Merlin Mustang would weigh 1500lbs more than the equivalent Spitfire. NAA, apparently through Ed Schmued, embarked on a detailed comparative analysis of all the main components of both aircraft and in January 1943 NAA were awarded with a contract to develop and build the XP-51F and XP-51G etc.

 

The IARC for P-51H-5NA 44-64181 records that it was delivered at the Inglewood plant on 13 June 1945 and assigned to Britain. The IARC shows that KN987 was ferried to Newark but there is no record that it was shipped to Britain and no record in the British system that it arrived.  It seems that it remained at Newark for some months until it was “made available” again to the USAAF on 17 January 1946 and ferried to MacDill AB where it apparently served with the USAAF until 16 May 1949 when it crashed near Pampa, Texas.

 

FR409 was delivered to Britain in August 1944, was evaluated at AAEE and reports written. FR410 was delivered to Britain in June 1945 and as far as I can find never officially evaluated. All the indications are that by that time Britain had no interest in these developments. FR410 was loaned out to a number of different British aircraft manufacturers for them to examine the engineering and test fly. I think Tony Buttler wrote a piece in Aeroplane Monthly on FR410 at Vickers (3 or 4 years ago?) … but I can’t find it at the moment.

 

As has been said the XP-51F was delivered in a paint finish but the XP-51G was delivered to Britain in an unpainted finish. I have always assumed that KN987 would have appeared in a similar way to FR410.

 

Steve

[gingerbob]

Nice to see you here, Steve!

 

Some "from the hip" comments, so don't hold it against me if I say something not strictly accurate:

 

Yes, the lightweights were another branch of the 1942 Mustang development tree, and clearly show the influence of RAF/MAP thinking of the time, which was inspired by close inspection of Herr Faber's Fw 190.  While Schmued was probably in the loop and interested from the beginning, the weight analysis was already underway before his trip to the UK (which I think "Mustang Designer" gives as the launch of this study).  Excess weight (and its impact on rate of climb) was already one of the chief complaints about the (Allison) Mustang from the USAAF, too, so it could be considered "general customer feedback" rather than uniquely British.  The nucleus of the Merlin idea (as a hot topic, rather than as an engineer's hypothetical) dates from April, while the Fw arrived in late July.  From that time (or shortly thereafter), the two branches of development were running in parallel.

 

16 minutes ago, SteveBrooking said:

I think Tony Buttler wrote a piece in Aeroplane Monthly on FR410 at Vickers (3 or 4 years ago?) …

 

Hmm, that DOES ring a bell, but I'm not confident enough in my own prospects to go searching upstairs (in the house, not "in my brain"- though that might prove apt enough) right now.  Maybe a more organized mind (no offense to anyone but myself) will pop in with the particulars...

 

Interesting details about the subsequent history of the "British" H!

 

bob

[303sqn]

There was an article in the Aeroplane, March 2017, on Supermarine test pilots and XP-51F.

[SteveBrooking]

Thanks Bob I have been lurking for a few years.. just a bit shy I guess...

 

I agree that the Lightweight programme ran in parallel with the P-51B/Merlin programme and did not intend to create that confusion.

 

NAA Engineering Department Report (NA-5567) “Weight comparison between the Spitfire IX and the P-51B” was dated 23 November 1942.  

 

Thanks 303sqn for the link to the article on the XP-51F the grey hair saps my memory.

[Ed Russell]

Thanks for all of your help. I shall advise my colleague to look for a different scheme if he wants authenticity.

[Work In Progress]

1 hour ago, Ed Russell said:

Thanks for all of your help. I shall advise my colleague to look for a different scheme if he wants authenticity.

Oh, he can do it with authenticity, just not with in-period authenticity. But since the type was irrelevant to the RAF's war effort, the 'in-period' angle doesn't seem important anyway 

Edited August 21, 2020 by Work In Progress

[Magpie22]

Note the red leather upholstery!!

 

[Dave Fleming]

On 21/08/2020 at 13:39, SteveBrooking said:

Hi

 

I have a friend in Canada who has spent many hours of his life trying to track down a photo of KN987.

As has been said the XP-51F was delivered in a paint finish but the XP-51G was delivered to Britain in an unpainted finish. I have always assumed that KN987 would have appeared in a similar way to FR410.

 

 

 

Here's a little curiosity - this pic is the only one I know of that claims to be XP-51G FR410/43-43336 in RAF markings., but it has the tall fin fitted to the XP-51J (and P-51H).  I think it has the larger canopy of the F/G/J series. Does anyone know of any other pics of FR410?
 

 

Edited October 27, 2020 by Dave Fleming

[Bedders]

I don't think that photo shows the real "tall fin" of the late H models. Even the "short" early H fin was taller than the normal D fin; but later they made the H fin even taller. The often-overlooked difference with the H fin was the increase in chord caused in part by employing a more vertical leading edge angle than on the D fin.

 

If only I had realised the finer points of all this before I built my 1/72 RS H model a few years ago. I have a new one to build but can't quite bring myself to start. I also recently acquired a long-sought-after CMR kit, only to find that it's inaccurate in a number of important areas. So it looks like I'll have to go 1/48 with the rather delicious-looking Modelsvit kit.

 

As far as an RAF liveried H-model is concerned, I believe that the KN987 recreation is indeed fictitious for 1945. NAA knew that the RAF fin flash wasn't that long for example, as shown by the photo of FR410 above. But in their desire for "something different", my guess is that model firms have probably chosen to ignore that error. Pity that post-war US-based H-model colour schemes are pretty dull compared to their wartime D-model sisters deployed overseas. One can imagine a 357FG H-model in RAF Dark Green and Medium Sea Grey with checkerboard nose and coloured rudder, and then the Whif dream fades away...

 

Justin

Edited October 28, 2020 by Bedders

[Ed Russell]

On 10/29/2020 at 8:22 AM, Bedders said:

CMR kit, only to find that it's inaccurate in a number of important areas

@BeddersIt would be interesting to see a fuller explanation of this. perhaps you might build it anyway and correct the errors - it would be an interesting WIP.

[Graham Boak]

Some of the ANG schemes on their post-war Mustangs were pretty colourful.  Including their Hs.

[diamant]

Hi,

 

This post is highly interesting for me.

 

On 10/27/2020 at 8:25 PM, Dave Fleming said:

 

Here's a little curiosity - this pic is the only one I know of that claims to be XP-51G FR410/43-43336 in RAF markings., but it has the tall fin fitted to the XP-51J (and P-51H).  I think it has the larger canopy of the F/G/J series. Does anyone know of any other pics of FR410?
 

 

 

 

Sorry for my ignorance but I wonder if the above photo was incorrectly labeled. 

 

If it actually was the FR410 (XP-51G),  shouldn´t have had a 5 blade propeller and shorter tail ?. 

 

Could be the FR409 (XP-51H) the one which appear in the photo?

 

Cheers

Santiago

 

 

[Work In Progress]

The two examples of the XP-51G only very briefly had five blade props, which proved unsatisfactory, and were quickly changed to Aeroproducts four-bladers, according to 

https://erenow.net/ww/mustang-thoroughbred-stallion-of-the-air/9.php

 

Here is another shot of the other G model, 44-76027, with a four-blade prop.  Nope, this is a J. see below. But it's true that most of the lives of the Gs were with four-blade props

 

 

 

This is FR409, with its three-blade prop. FR409 was an XP-51F, there was no such thing as an XP-51H, they put it direct into series production without XP prototypes.

Edited December 30, 2020 by Work In Progress

[diamant]

Thank you for your reply. 

 

Sorry, you are right. I should say P51H instead of XP-51H.

 

What still does keep my wondering is the length of the tail of the apparently FR410. It looks much larger than the G version.   Could be the perpective?. 

 

Cheers

Santiago

[Work In Progress]

The fin and rudder look the same to me on both the G models in those pictures above, 44-76027 and 43-43336 / FR410.

[Ed Russell]

From IPMS Mustang guide

 

The ultimate version of the Mustang was the P-51H, which was the fastest Mustang variant to see service and one of the fastest (if not the fastest) piston-engined fighters to enter production during the Second World War. However, it was destined never to see any combat, having entered service too late to participate in the final action against Japan.

Rather than commit the F or G versions to production, the USAAF decided instead to produce a version powered by the uprated Packard Merlin V-1659-9 engine. North American Aviation gave the project the company designation NA 126, and it was ordered into production as the P-51H in June of 1944 even before much of the initial design work was done.

The fin and rudder in the P-51H were significantly increased in height and the rear fuselage was lengthened to produce an overall length of 33 feet 4 inches (nearly two feet longer than the P-51D). Other features were taken directly from the XP-51F project--it had the same shallower carburetor air intake underneath the nose and modified cowling with integral engine mounting, the same simplified undercarriage with smaller wheels and disc brakes, and it had the same broad-chord wing without the leading edge "kink". However, the cockpit canopy was much smaller than that of the XP-51F, being more nearly equal in size to that of the P-51D. The profile of the canopy was somewhat different from that of the P-51D, with the top of the hump being much closer to the front just above the pilot's head.

[Dave Fleming]

On 27/12/2020 at 13:48, diamant said:

Hi,

 

This post is highly interesting for me.

 

 

 

Sorry for my ignorance but I wonder if the above photo was incorrectly labeled. 

 

If it actually was the FR410 (XP-51G),  shouldn´t have had a 5 blade propeller and shorter tail ?. 

 

Could be the FR409 (XP-51H) the one which appear in the photo?

 

Cheers

Santiago

 

 

The taller tail was first introduced on the J, and was seen in the H. I pondered if it was the elusive H, but the canopy seems too large, so I wonder if the second G had the larger rail too.

[John M]

15 hours ago, Dave Fleming said:

The taller tail was first introduced on the J, and was seen in the H. I pondered if it was the elusive H, but the canopy seems too large, so I wonder if the second G had the larger rail too.

Dave,

The photo is of FR410, the 2nd XP-51G. The first XP-51G (43-43335) had it's 5-bladed Rotol prop and short tail replaced with a 4-bladed Aero Products prop and a tall tail. So in effect both' G's  (43-43335 & 43-43336) and both J's (44-76027 & 44-76028) received the NA-117 tall tails.. The NA-117 eventually became the NA-126 P-51H.

Short tails were 74 inches in height and the tall tails  84 inches,

John

[Bedders]

On 12/27/2020 at 2:12 PM, Work In Progress said:

Here is another shot of the other G model, 44-76027, with a four-blade prop.

 

 

I think this is in fact the XP-51J with the Allison engine and multitude of tiny exhaust stacks. It flew after the H and has the early, short H-style fin/rudder.

 

[Work In Progress]

Yeah, you're right, I screwed that up. The two examples of the G were 43-43335 and 43-43336 as John M said above