RAF mustang query

[PaulR]

Hallo there,

am contemplating building a RAF sharkmouthed P-51 mk IV in 112 sqn marks. Would I be right in thinking it RAF P-51 MK IVs were actually P-51Ks, and therefore need the 'uncuffed' prop blades? Also, would they have had the regular hood, or the bulged 'Dallas' hood?

Thanks for any guidance,

Paul

[Test Graham]

RAF Mk.IVs were Ds. RAF Mk.IVAs were Ks. The RAF had both - I think it is true that the UK generally operated Mk.IVs whereas the ones in Italy were predominantly Mk.IVAs, but wait for the howls when people read that. I'm not claiming that both types were not seen in both theatres.

The canopy varied, and no simple rule applied. Dallas built Ds and Ks. Look for a photo of the aircraft you wish to model.

Look also for variations such as the louvres over the nose.

[PaulR]

RAF Mk.IVs were Ds. RAF Mk.IVAs were Ks. The RAF had both - I think it is true that the UK generally operated Mk.IVs whereas the ones in Italy were predominantly Mk.IVAs, but wait for the howls when people read that. I'm not claiming that both types were not seen in both theatres.

The canopy varied, and no simple rule applied. Dallas built Ds and Ks. Look for a photo of the aircraft you wish to model.

Look also for variations such as the louvres over the nose.

Cheers Graham.

Interesting to know there was no hard and fast rule.

Regards, Paul

[Kallisti]

Doh should try reading the topic prpperly - talking about Mustang IV not III...

Edited May 6, 2012 by Kallisti

[Welkin]

P-51D Mustang IV

KH641 - KH670

KH944 - KH946

KM493 - KM743

P-51K Mustang IVa

KH671 - KH870

KM100 - KM492

[Test Graham]

Robin Brown's Shark Squadron lists 21 aircraft with their unit code letter under Mustang Mk.IV, although three of them noted as Mk.III or IIIB(?) and four have FB serials. KH586 and and KH476 earlier than those given above, presumably also Mk.IIIs, and KM872 is later. The rest appear to be all strictly Mk.IVAs, using the ranges quoted above.

Looking for further help in Air Britain, KH944 -946 are Waco Hadrians diverted to the RCAF but otherwise agree with Welkin. KH476 is indeed a Mk.III but not listed as serving with 112 Sq. Possibly it was a borrowed aircraft flown by a 112 Sq pilot and noted in his logbook without note of ownership.

The book has two photos. Camouflaged GA.S KH774 with Aeroproducts prop and (I think!) Dallas canopy - although I gather that there were more than just the two variations. Bare metal/Aluminium painted GA.K KH832 with Aeroproducts prop and indeterminate canopy.

Note that some kits provide uncuffed Hamilton Standard propellors, suitable for some Pacific theatre and many postwar P-51s. These are not the same shape as the Aeroproducts propellor.

[Jennings Heilig]

Keep in mind that aside from the prop (Aeroproducts vs. Hamilton Standard) there was essentially no difference between a D and a K. The only way to know which was which is the serial number. The carb filter intake louvres were not a positive identification feature (I believe those were all added after production), nor was the canopy (there were at least 6 different P-51D/K canopies, btw). Props could be, and were swapped. Plenty of pics of K's with HS props. Everyone I've spoken to who was involved (including pilots and crew chiefs) universally hated the Aeroproducts hollow bladed prop, as they were impossible to keep balanced properly. The slight imbalance problem manifested itself with cracked engine mounts and seal problems (not to mention a crappy ride for the pilot).

[Welkin]

Keep in mind that aside from the prop (Aeroproducts vs. Hamilton Standard) there was essentially no difference between a D and a K. The only way to know which was which is the serial number. The carb filter intake louvres were not a positive identification feature (I believe those were all added after production), nor was the canopy (there were at least 6 different P-51D/K canopies, btw). Props could be, and were swapped. Plenty of pics of K's with HS props. Everyone I've spoken to who was involved (including pilots and crew chiefs) universally hated the Aeroproducts hollow bladed prop, as they were impossible to keep balanced properly. The slight imbalance problem manifested itself with cracked engine mounts and seal problems (not to mention a crappy ride for the pilot).

I recall reading somewhere that 19 Squadron had real problems formation flying with mixed P-51Ds and P-51Ks, as the cruising speed of the P-51K with the Aeroproducts prop was significantly lower than that of the P-51D with the HS prop.

[Jon Kunac-Tabinor]

Given that the Aeroproducts prop was so unpopular - one does wonder why they bothered fitting them? Was it just down to a shortage of the HS Cuffed ones?

Cheers

Jonners ( and apols for the semi hijack)

[Terry McGrady]

Given that the Aeroproducts prop was so unpopular - one does wonder why they bothered fitting them? Was it just down to a shortage of the HS Cuffed ones?

Cheers

Jonners ( and apols for the semi hijack)

Well not that "Unpopular" as all but 29 of the RAF Mustang IV/IVA that actually reached service were P51K Mustang IVA.

19% of the September 44 production had problems with excessive vibration with these props . The problem was solved , though how I don't know

Cheers

Terry

[Terry McGrady]

I recall reading somewhere that 19 Squadron had real problems formation flying with mixed P-51Ds and P-51Ks, as the cruising speed of the P-51K with the Aeroproducts prop was significantly lower than that of the P-51D with the HS prop.

Yes I read that too Also read somewhere that statement was incorrect

Cheers

Terry

[Test Graham]

Given that the Aeroproducts prop was so unpopular - one does wonder why they bothered fitting them? Was it just down to a shortage of the HS Cuffed ones?

The usual reason for introducing a parallel item is an expected shortfall of the prime item. Which doesn't always happen, but by then the mills are grinding. Any problems not discovered in early testing - and in this case clearly no serious problem was found - will not appear until well down the line with many aircraft in service and many more sitting in various stages of production. If this problem was not settled in the field (as suggested) then it would be fed back to the manufacturers/authorities and they would introduce their own studies before deciding on (for example) a cancellation of the production of the parallel item. This all takes time, during which the debatable item continues in service and in production. It is not just a matter of stopping the production of the item, but of increasing the production of the preferred part to match not just the newbuilds but all others retrospectively.

The comment that 19% of one month's production had problems suggests that 81% didn't. It is not clear from Terry's comment whether this was restricted to one month or can be considered more general, but it may not matter. Once word got around that the prop was having problems then it would be a case of "give a dog a bad name". Many a failing that would have gone unnoticed as run-of-the-mill on the HS prop would be more cess to be piled on the Aeroproducts.

Edited May 8, 2012 by Graham Boak

[Terry McGrady]

Hi Graham

Certainly not come across any reports that the RAF had problems with the Aeroproducts prop

Regarding the 19% of September 44 production having problems , production of the P51K only started that month , so may have just been teething troubles .

I've not seen any other reference to this

Terry

[Test Graham]

In the absence of specific reports, it might be worth looking for photos of Mk.IVA serials equipped with HS props. If there are more than just a handful then we can take this as evidence of a preference existing in the RAF too. I take it we can rule out Mk.IV serials with Aeroproducts props? Best not to assume that, really.

[Terry McGrady]

In the absence of specific reports, it might be worth looking for photos of Mk.IVA serials equipped with HS props. If there are more than just a handful then we can take this as evidence of a preference existing in the RAF too. I take it we can rule out Mk.IV serials with Aeroproducts props? Best not to assume that, really.

Never ever seen a MKIVA with an HS prop probably because there were so few MKIV and related props immediately available

Of the 400 or so RAF Mustang Photo's I have , not come across one.

Only the first 29 P51D-NT (ie KH641-70 less 1 which crashed in the US) Saw any significant service

Of the 29 at least 2 were used at Boscombe down and one sent to the Med according to the forms 78

The later deliveries of P51D KM492 -743 were never used operationally and very few actually flew in RAF service

These were P51D20 and 25-NT. Though I have seen a photo of one of these Airframes with the cuffless "squared off "

HS props

Production of the P51K finished in March 45

Dallas building more D models than they did K

Terry

Edited May 8, 2012 by Terry McGrady

[Jennings Heilig]

The absence of complaints doesn't mean there weren't complaints. You'll notice that no P-51s after WWII used the Aeroprop (even K's), and that during the war many K's (at least in USAAF service) were retrofitted with HS props. It's also telling that Dallas built D's, then K's, then switched back to D's. Everyone I've ever talked to says that the Aeroprop was junk and it was universally hated by everyone who flew or maintained the airplanes. I'm sure there were probably individual props that were fine, but the majority seem to have had balance problems that couldn't be solved except by replacement with an HS prop.

The reason many RAF birds may not have gotten the HS prop might well have been simple logistics. The supply chain may simply not have reached them.

The last batches of D's did in fact leave the factory with the cuffless HS prop that is most often associated with post-war Mustangs.

[Test Graham]

The absence of complaints does not prove that there were no complaints, but it does make it hard to prove their existence. It wouldn't be the only piece of wartime kit to receive a slating from one user but be no problem to another. Or indeed to have problems in an early stage that were, or could be, ironed out with experience. The short duration of Aeroproducts production could be as equally well be explained by only being needed to fill a short gap in the production of HS props, as that they were cancelled on the grounds of inadequacy. Postwar standardisation would equally be the pressure behind their removal. P-47s and B-26s were also removed from the inventory, but not for any intrinsic failings. With a much lower requirement for numbers, only the best was retained. The Aeroproducts prop clearly wasn't the best.

The point I'm trying to make is that there is always a lot going on behind the scenes, and the often-repeated simple straightforward explanation is not necessarily the only, or even the key, reason behind decisions.

Edited May 8, 2012 by Graham Boak

[Terry McGrady]

The absence of complaints doesn't mean there weren't complaints. You'll notice that no P-51s after WWII used the Aeroprop (even K's), and that during the war many K's (at least in USAAF service) were retrofitted with HS props. It's also telling that Dallas built D's, then K's, then switched back to D's. Everyone I've ever talked to says that the Aeroprop was junk and it was universally hated by everyone who flew or maintained the airplanes. I'm sure there were probably individual props that were fine, but the majority seem to have had balance problems that couldn't be solved except by replacement with an HS prop.

The reason many RAF birds may not have gotten the HS prop might well have been simple logistics. The supply chain may simply not have reached them.

The last batches of D's did in fact leave the factory with the cuffless HS prop that is most often associated with post-war Mustangs.

So what you are saying is that of the 1500 P51K built over 1000 or more suffered with prop problems rather than the 19% of the September 44 production ?

Seems like the story gets exaggerated with the telling

Edited May 8, 2012 by Terry McGrady