Information on Rare British Aircraft Engines

Thank you for the clarifications regarding the XP-51G airplane176. It’s easy to see how that mistake could be transcribed down through the years…

Thank for all of your suggestions. Yes, the A-36 was the Apache. My apologies.

I got in touch with David Birch of the Rolls-Royce Heritage Trust. The engine in the XP-51G was a Merlin 100 (RM.14SM rating). Two additional engines were sent to Wright Field for testing. One in now in the NASM. I suspect that the person(s) gathering data for the Army Model Designations was unfamiliar with British designation systems and recorded what they thought was a model number.

Is there some contact point or person for research requests within the Ricardo Company?

Thank you,

Roger

But Ex Brat does have a point: the published “works of others” regarding XP-51G repeated the oft-plagiarised ‘Merlin 145’ statement, whereas the primary source doc revealed it to be 14SM.

Helpful suggestions should never be discouraged, but it’s a fine line between that and the “I just Googled it” response.

…did anyone read the first few words of the initial post of airplane 176 ?….

…pontificating on the why’s and wherefore’s of how a “research” should be conducted should not be a deterrent to any help that may be offered….

Research.

Avoid the works of others where possible; that’s not research. For Ricardo you could try the company that still bears his name. They hold a large archive that they often share with those who have a genuine research enquiry.

You have my vote on that one! – hence my offer of TNA assistance. The truth will out!

….Apologies….

Detective,

I believe that the naming by the RAF is true. US aircraft did not have official names until early in WW2, when it was realized that the official designations might give away too much information, such as the state of development i.e. P-51A, P-51B, P-51C… The attack version, A-36 that was the first large-scale order for US use, was initially to be named Invader (later used by the A-26), but renamed to match the fighter.

Roger

In danger of thread creep here, but is this a debate on Mustangs or engines? I don’t see the relevance of the aircraft name when it would seem that the original query was solely in respect of an engine type?

(I thought A-36 was Apache btw 🙂 )

Detective,

I believe that the naming by the RAF is true. US aircraft did not have official names until early in WW2, when it was realized that the official designations might give away too much information, such as the state of development i.e. P-51A, P-51B, P-51C… The attack version, A-36 that was the first large-scale order for US use, was initially to be named Invader (later used by the A-26), but renamed to match the fighter.

Roger

Hi Roger .. I thought the “Mustang” appellation was given by the British at the outset and was taken up by the U.S. at a later date….

…another quote by the same previous author…”The first production Mustang, as the fighter had already been dubbed by the R.A.F., flew within a year of the prototype”….

Detective,

… just reading between the lines here, I’m reasonably certain the U.S. were also referring to the P-51 as a “Mustang” by that late stage of the War….??

I’m not sure what you are saying here. All P-51 were Mustangs.

Roger

… just reading between the lines here, I’m reasonably certain the U.S. were also referring to the P-51 as a “Mustang” by that late stage of the War….??

Schneiderman,

Thank you, I did find the oldmachinespress website (see post 10) and it did clear up some mysteries.

Detective,

Thank you also. As you say, the two XP-51G were built in the US. One was provided to the RAF, and one remained in the states to hopefully be eventually restored to flight status http://xp51g.com/XP51G/Welcome.html. I am trying to identify the specific Rolls Royce mark number of the (British-supplied) engines. RM.14SM, as Sabrejet shows in an official Army document, is a rating specification if I understand the British system correctly. The best source that I have available is Lumsden, and he shows 18 experimental Merlin 100 or 101 built rated as RM.14SM. Perhaps at least two of these were sent to the US for this purpose. I remember reading (I unfortunately do not remember where) that Hap Arnold was anxious to have a 100-series Merlin for test in the US. Other RM.14SM rated engines include the Marks 102, 130 to 134, 140, 300, 600, 620, and 621.

Sabrejet,

Thank you for reminding me of this important document. I do have a copy. I was looking through the 1945 and then 1946 editions and I remembered another US Merlin mystery in the Douglas XC-115. This was a Merlin-powered C-54 that was not built. Most sources list the engine as a Packard V-1650-209 of 1650hp. The Army Model Designations of 1946 shows “Packard V-1650-20SM. Could this have been a proposed Packard-built version of the 600-series Merlin or yet another typo? Lumsden lists no RM.20SM.

Thank you all for your continuing help and interest.

Roger

Roger,

Been trying to find some primary-source info on the XP-51G and thought I had some NAA files on this machine: they elude me for the moment. However I did find this, which I think demonstrates the extent of plagiarism that’s gone on since 1945! It answers your question nicely too: RM14SM it is!

[ATTACH=CONFIG]243829[/ATTACH]

[ATTACH=CONFIG]243830[/ATTACH]

Hi All .. From William Greens’ very well written book first published in 1957, “Famous Fighters of the Second World War” .. regarding the enquiry about the XP-51G engine installation, and I quote …..

….”Two further lightweight Mustangs were produced, designated the XP-51G. These were fitted with the 1,500 h.p. Rolls-Royce Merlin 145 which drove a five-bladed Rotol airscrew, and the XP-51G, which weighed only 8,879 lb., attained a maximum speed of 472 m.p.h., one (FR410) being supplied to the R.A.F. The designation P-51E was unassigned, but the development work on the lightweight Mustang materialized in the production P-51H which emerged towards the end of 1944, 555 being completed by V-J Day out of an original contract for 1,445 machines. The P-51H had a Packard Merlin V-1650-9 which delivered a maximum of 2,218 h.p. at 10,200 feet under war emergency conditions,” …….etc. etc……

…end Quote ..

….I’m fairly certain that these two machines were produced in the USA… with, as stated, one only being shipped to the R.A.F. for evaluation…

….I hope that is a bit of help with these interesting studies….Cheers

You may have found this already but is information on A-S engine projects, including Boarhound, here

http://oldmachinepress.com/2015/10/27/armstrong-siddeley-dog-aircraft-engines/

Sabrejet,

Thank you for the Cruciform info. It appears that we were typing at the same time. I have all of the US Putnams, but only a few of the British (RAF, RN, British Fighters, British Bombers, RFC).

Roger

Some more digging might indicate that both the 600 HP Ricardo and the Cruciform were to be built by Brotherhood, and that the Cruciform was a Ricardo project. See here:

http://www.crossandcockade.com/forum/forum_posts.asp?TID=265

Ricardo had some form of working relationship with the Brotherhood company.

Roger

According to Bristol Aircraft (CH Barnes, Putnam1964 etc), regarding design of the Scout E,

“…Capt Barnwell was informed of a proposal by Harry H Ricardo and Frank B Halford for a ten-cylinder two-row watercooled radial of 200hp, the ‘Cruciform’. This engine gained no official support and was not built even as a prototype, but nevertheless Barnwell built around it two alternative single-seater schemes, one a tractor biplane and the other a pusher”.

Sabrejet,

That would be most appreciated. Thank you.

I did find a fairly recent, excellent article by William Pearce on the AS “Dog” engines here:

http://oldmachinepress.com/2015/10/27/armstrong-siddeley-dog-aircraft-engines/

Thank you again,

Roger

Sabrejet,

I am little bit distant from the National Archives as I am in the USA. The listings you show look like a promising start. Maybe someday…

Roger

Roger,

Next time I’m up there (hopefully next month or so) I’ll have a look at those and see if they’d be of use: I’ll copy any pertinent info and pass it on.