Merlin "copied" from the Curtiss V-12?

A.A. Rubbra:
“The “F” engine, later to be called the Kestrel, had been prompted by the success of the Curtiss D12 liquid-cooled engine in the USA. This engine used aluminium cylinder blocks with steel liners instead of separate steel cylinders with welded-on jackets, a construction wich considerably increaded the beam stiffness of the crankcase and the ability to use higher rpm and powers without crankcase trouble. Work on the “F” engine was further spurred on by the purchase, by the Fairey company, of a number of Curtiss D12 engines for installation in the Fairey Fox.”

Powerandpassion:
All the Rolls-Royce V12s from the Kestrel through to the Merlin used single piece blocks, with the exception of the Merlin I, and most marks of Merlin from the Mk22 onwards, from mid 1941. Ford were still building the highly successful Merlin XX as late as 1944, so clearly it shouldn`t have been, and wasn`t strangled at birth.
Naturally aspirated Kestrels, and others, also had carburettors in the vee of the engine.

Personally, I think the original comment by Paul Kennedy is poorly researched and plain wrong, but clearly Rolls-Royce were influenced by the aluminium single-piece block on the D12. but there are no detail similarities between the two engines.

Pete

Just for the record, it was Charles Fairey, [not people connected with RR], who brought a D-12 engine back to England from the US- stowing it in his stateroom, where he could keep a close eye on it.

Arthur Rubbra, “…designer of many of Rolls-Royce aero engines…” [http://en.wikipedia.org/wiki/Arthur_Rubbra] appears to have had something to say about the Curtiss D-12 on page 19 of his book, “Rolls-Royce Piston Aero Engines – A Designer Remembers.” Rolls-Royce Heritage Trust. Historical Series no 16. 1990

….that is, judging from what can be gathered from the Wiki article on the Kestrel [see footnote 3 below.]

Can anyone take a look at Rubbra’s book?

http://spitfiresite.com/2010/04/the-development-of-rolls-royce-merlin-engine.html

http://en.wikipedia.org/wiki/Rolls-Royce_Kestrel

“…The Kestrel came about as a result of the excellent Curtiss D-12, one of the first truly successful cast-block engines. Earlier designs had used individually machined steel cylinders that were screwed onto a crankcase, whereas the cast-block design used a single block of aluminium that was machined to form cylinders. The result was both simpler to build as well as lighter and much stronger, requiring only an investment in new machining equipment.”[3]

“The D-12 was one of the most powerful engines of its era, and continued to swap records with other contemporary high-power engines. No British company could offer anything like it, and when Fairey imported 50 of the type (renaming them as the Fairey Felix) the Air Ministry had enough and ordered Napier & Son and Rolls-Royce to start work on cast-block engines of their own.”

“Arthur Rowledge, one of Napier’s chief engineers and the designer of the Napier Lion engine, became fed up with management and left for Rolls.[4] In this one move any Napier design effort ended while Rolls’ got a boost. Applying every known advance since the D-12 was introduced, Rowledge designed the new engine to use supercharging at all altitudes, allowing it to outperform naturally aspirated engines by as much as they were willing to increase the boost pressure.”

D12 was great but RR ‘R’ and Kestrel must have been better, because the D12 is sitting in the bar with James Dean, Marilyn, Betamax & the Edsel, while the Kestrel had more children than a rabbit. And these bunnies carried 303s, they really got a result.

After Curtiss merged with Wright at the end of the ’20s the management decided to concentrate on Wright’s air-cooled radials, so Curtiss’ watercooled engines languished. If they had continued development there is every possibility that thye could have given R-R a run for their money

This is from a minute dated 4.12.26 in in AIR 5/436 “General Position of Schneider Cup Aircraft”

I think this shows that the Buzzard and “R” were derived from both the Condor and the F.X ( aka Kestrel) and that there was, even in 1926, an an intent to produce a racing engine from this development.

Hi Philip,

There were indeed a least a couple of proposals to develop the Condor for racing, the earliest of which I’m aware being in 1924 for the Supermarine Sea Urchin. However the RR board was split between those that wanted to concentrate on cars and those that wanted to develop the aircraft engine division, and racing wasn’t too popular with either as failure could damage their reputation. Luckily a more enlightened attitude prevailed in the second half of the ’20s
The Condor really has very little in common with the F. It was an aging design with separate cylinders and waterjackets while the F was a clean start with monoblock construction, as others have said, ‘inspired’ by the D-12

I recently read that RR sales engineers in wartime visited advanced airbases to purposely provide incorrect maintenance tips to mechanics servicing Napier Sabres, causing a few Tempests to sink in the Channel. .

And, of course, the author of that little gem failed to explain how, and why, those engineers were not found guilty of treason, and hanged.
Strange that, about 20 years ago, a former Napier employee never mentioned it, only saying that, once they’d persuaded the RAF groundcrews to stop tinkering, and leave the factory settings intact, the Sabre was fine.

I must say that I recently read that RR sales engineers in wartime visited advanced airbases to purposely provide incorrect maintenance tips to mechanics servicing Napier Sabres, causing a few Tempests to sink in the Channel.

An interesting comment, can you provide the source please.

D12 Buzzardry

D12 was great but RR ‘R’ and Kestrel must have been better, because the D12 is sitting in the bar with James Dean, Marilyn, Betamax & the Edsel, while the Kestrel had more children than a rabbit. And these bunnies carried 303s, they really got a result.

D12 head was not removable, you needed to lift the combined cyclinder block casting & head bank off the D12 together, certainly not copied in the ‘R’ or Kestrel. Any mechanic would have strangled this at birth.

D12 carburettors/intake sat on top of the engine, resulting in the mohawk look for Fox front end and some pretty plain looking contemporary Curtiss aircraft. Kestrel tucked the carb in underneath like a well bred lady, which resulted in the Hart, Hind nose, which for a slightly paunchy, middle aging chap like myself is disco hot.

I think that if RR had copied the D12 then I would be eating saurkraut and sushi for breakfast. If they had not stripped down a competitor’s engine then they would not be doing their job, a form of thoroughness similar to fact checking in journalism.

I must say that I recently read that RR sales engineers in wartime visited advanced airbases to purposely provide incorrect maintenance tips to mechanics servicing Napier Sabres, causing a few Tempests to sink in the Channel. Though this is off topic, it appears a form of buzzard like behavior which disappointed me to read. Accordingly I have cancelled any intention to buy a new Rolls Royce. Perhaps the author of the cited work meant to say that RR started with a D12 and returned a Buzzard.

I think there is reference to this in Leo McKinstry’s Spitfire book (although it may be another similar tome) and the key here is ‘Inspired’ not copied. If I recall properly, R-R bought one D-12 (shipped it back in first class cabin I think?) and gave it a thorough going over. Subsequent engines were apparently influenced by some design features.

Yup when the Mini came out Ford could not understand the price that was lower than the Anglia, so they bought one, stripped it down to individual component parts and costed each part on how much it would cost Ford to produce, they concluded BMC were losing £30 odd on each one they sold, it was later to be proved correct, the price having come out of the Chairmans head without looking at any costings ……

Similar Dyson couldn’t sell his designs to any of the big producers, so went it alone, it’s not without looking at his world beating designs that they have managed to come up with similar, they would need to so as to ensure they didn’t infringe any of his patents.

hdl’s #5 link to a Smithsonian Paper traces aero-engine descent from Hispano and Mercedes, licences in and out and roundabout. A conclusion might be that, just as The Rolling Stones could not have thrived without, ah, influence, so ditto likewise Merlin. Not copied from anything, but not conceived in isolation.

Why is it in Aero that we all try to own, say Concorde (it’s British…no, it’s French)? There’s a continuum, “owned” by nobody.

Unless of course you are looking to create a bit of a controversy to promote your new book that is. Failing that just plain lazy journalism.

Calm down, Timmy, it’s not my book. My name is Stephan Wilkinson. The author of the book is Paul Kennedy. Not understanding that is just plain lazy reading.

The ‘H’ – later Buzzard- was basically a scale-up of the ‘F’ and the racing ‘R’ was a beefed-up ‘H’. The original Griffon in 1933 was a derated ‘R’ but the wartime Griffon was a completely new engine, albeit with the same cylinder dimenssions. None of these engines were related that closely to the Condor, which was old-tech by 1927 and had had its day.

This is from a minute dated 4.12.26 in in AIR 5/436 “General Position of Schneider Cup Aircraft”

With reference to the last paragraph of conclusions, Messrs. Rolls-Royce have been asked to investigate the possibilities of redesigning the Condor engine on the same lines as the F.X. engine. In the first instance we are proposing to build a service engine of this type and later on to boost it up to see what can be done for racing purposes. The capacity of the Condor III engine is 2138 cubic inches, and if developed on the same lines as the Lion Series VIIA engine the redesigned engine should develop 1070 B.H.P. @ 2600 R.P.M. and would weigh approximately 1000 lb. Action is being taken with Messrs. Rolls-Royce with a view to producing three engines of the new type, and it is understood that the designs will commence in three weeks from date. As soon as the scheme drawings have been completed we shall be able to give you more data with regard to frontal area, horse-power and weight.
R.D.E.3
4.12.26. (Signed) A.D./R.D.E

I think this shows that the Buzzard and “R” were derived from both the Condor and the F.X ( aka Kestrel) and that there was, even in 1926, an an intent to produce a racing engine from this development.

At the time Mr Handley Page fell foul of our American cousins and had his civil O/400 impounded and then ‘released’ to Curtiss, he was known as Fred or Frederick. He was knighted in 1942, after that, and the Curtiss D-12 that started this thread, had passed into history. Actually, regardless of whether he’d been knighted, everyone called him ‘HP’.

I meant to provide some historical accuracy, not disrespect to the man.

Rolls Royce had bought many other competitors engines and cars over the years – indeed the original Rolls Royce 2 cylinder car was only built after Sir Henry ( I won’t call him Fred! ) had obtained a Decauville and had it taken to the original Cooke Street works in Manchester and helped strip it down himself. I know that later on various Packard and Mercedes cars were subject to a similar treatment, and surely most of Roll’s competitors were doing similar things, makes good commercial sense to find out what the opposition are up to.
To say however that they took the Curtiss engine and ‘rebuilt it’ as the Kestrel et al is palpable rubbish. Unless of course you are looking to create a bit of a controversy to promote your new book that is. Failing that just plain lazy journalism.

A detailed history of the Curtiss D-12 and its impacts can be found here-

http://www.sil.si.edu/smithsoniancontributions/AnnalsofFlight/pdf_lo/SAOF-0007.pdf

[“The Influence of the D-12” begins on page 86]

I often wonder how Mitchell went from the type 224 to the Spitfire,and whether there was an influence of the Heinkel 70 creeping in to the ‘concept’.
Of course this is all refuted by various documents,but there does seem to be a transfer of quite major features if you view it objectively.
Thats not to take away credit with the resultant product,but in the main most progression is the result of ‘improving’ a good formulae.

Try this. A very interesting read.

Mark

http://www.amazon.co.uk/Secrets-Spitfire-Shenstone-Perfected-Elliptical/dp/184884896X

Note to self: Don’t type answers when completely cream crackered and half asleep with a cat on your lap! I got my Buzzard and Condor mixed up.

Back to sleep….

As I understand it the Air Min were not too happy with Fairey obtaining a licence to build the D-12, they did not want another engine manufacturer in the UK. So, they urged Napier to build something comparable but they declined as they felt the Lion still had plenty of life. RR were then asked and as Hives was in favour of revitalising the aircraft engine division they agreed. I think that they did indeed disassemble a D-12 prior to designing the ‘F’ – later Kestrel.
The ‘H’ – later Buzzard- was basically a scale-up of the ‘F’ and the racing ‘R’ was a beefed-up ‘H’. The original Griffon in 1933 was a derated ‘R’ but the wartime Griffon was a completely new engine, albeit with the same cylinder dimenssions. None of these engines were related that closely to the Condor, which was old-tech by 1927 and had had its day.

Variations on a theme

I often wonder how Mitchell went from the type 224 to the Spitfire,and whether there was an influence of the Heinkel 70 creeping in to the ‘concept’.
Of course this is all refuted by various documents,but there does seem to be a transfer of quite major features if you view it objectively.
Thats not to take away credit with the resultant product,but in the main most progression is the result of ‘improving’ a good formulae.

This was also posted on the other thread that included this, The Griffon was a development of the R series which were developments of the Condor that was built several years before the D-12