What if?

sg: “but I know what I’d rather have up front, RR, London, Derby, the known universe”. Most Merlins did not come from “proper” RR. Crewe was largely Paddies and colleens unfamiliar, on arrival, with any factory; as for Glasgow, well..:Hornby,Official History, Civil, Factories & Plant,P.290: Hives seen by Ministers as “courageous” agreeing to enter Red Clydeside with “some qualms whether (a name) synonymous with luxury (might arouse) antagonism”. Intended, like Crewe, for Vultures (!), it peaked at 5% fully Aero-skilled men. Both sites had Derby-detached supervisors…but they knew little of the specific product, and less about volume.

Ford/Trafford Park came to Hooker with “a problem”, involving, he assumed, tolerances beyond auto competence. Not so: inter-changeability of parts, essence of Model T et seq but alien in short-run Aero, required more precision than Royce had designed in. As dhfan says, it took them a year to redraw, then to churn out “very good” (Hooker) Merlins, cheaper than the parent by 30% Ritchie, Industry and Air Power,P.246 (in part due to scale): >”40 different Marks of Merlin were produced at Derby during the war. Ford produced just 5 (very similar) variants (yet) produced only 2000 fewer engines in 5 years than Derby produced in 7.”

cd: “…the quality of Bristol engines”. Same point: many Hercules came from Accrington – “diluted” hands plus exiled cider-quaffers. Many Hercules came from auto firms, co-ordinated by Austin: Ritchie,P.246: Ministry of Labour: “an object lesson (the) best monument of what can be done by careful Govt. planning and methodical industrial execution. Each site represents the highest attainment of the engineer’s art in mass production.” Hoover props, Bus garage Halifax, Spit: miraculous that our grandmothers delivered what they did.

Packards..

I think it was to do with the looser build and machining tolerences of the US counterpart.I know they had a lot of trouble with the MkXVI,s.Interesting that I haven,t heard much about the Packards in the Mustangs being so troublesome.

I seem to remember that Hooker moved on to Bristol’s after a row with Lord Hives, whilst he was trying to resurect the Avon.

Interestingly even though ford had to redraw the Merlin,and so did Packard, they all fit together, as well as the Meteors built by Rover; I’ve heard all the stories about Ford engines being better, and Packard’s too, but I know what I’d rather have up front, Rolls-Royce, London, Derby, the known universe.

Apparently there were some concerns about Packard Merlins throwing their conrods and they ran much rougher than the Rolls version at certain parts of the rev range. Allegedly reps from Rolls had to come and give lectures extolling the virtues of the Packard built versions to squadrons who had lost faith in these models. They were a bit more powerful than the Rolls versions though.

I seem to remember that Hooker moved on to Bristol’s after a row with Lord Hives, whilst he was trying to resurect the Avon.

Interestingly even though ford had to redraw the Merlin,and so did Packard, they all fit together, as well as the Meteors built by Rover; I’ve heard all the stories about Ford engines being better, and Packard’s too, but I know what I’d rather have up front, Rolls-Royce, London, Derby, the known universe.

… and also rescued Rolls-Royce after the RB.211 debacle.

Plus a government bale-out…and quite rightly so!

It was Ford producing Melins, in Sir Stanley’s words “like shelling peas”.

There was a year’s delay while they redrew the Merlin to motor industry mass-production standards rather than the RR hand-built standards.

Yes, it must have helped bring Rolls-Royce engines close to…

…the quality of Bristol engines! 😀

… and also rescued Rolls-Royce after the RB.211 debacle.

It was Ford producing Melins, in Sir Stanley’s words “like shelling peas”.
There was a year’s delay while they redrew the Merlin to motor industry mass-production standards rather than the RR hand-built standards.

Sir Stanley Hooker

There can’t be many engineers who did so much for air-superiority in 1939-1945 and…

…did it all again in 1982 with the Pegasus in the Sea Harrier!

I’ve not read his book…it’s on my list though.

Not so much Rolls-Royce as Dr. Stanley Hooker.

Rolls-Royce employed him, not knowing what he could do – and neither did he. It was extremely fortunate that all his previous pure research equipped him to become probably the world’s leading expert on supercharging.

I was looking to see if Sir Stanley’s name appeared. His book “Not Much of an Engineer” details his time at RR, and the turnaround of the Merlin. Also interesting to read is how much the engines improved once a major car manufacturer (Ford I think) started manufacturing them in the UK – they were expecting quality issues with them IIRC, only to find they were better than RR’s own…:)

You mean lacking a two-stage or turbo supercharger?

I beg your pardon, single-stage supercharger indeed.

It says something for the performance of the Merlin that a pilot flying a Spitfire LF MkIX – that is, with a Merlin optimised for low-level flying, could reach 43,000ft on an air test (though it did have the two-stage supercharger). The pilot reached 600mph on the way down! (Source ‘Spitfire dive bombers vs the V2’, Pen and Sword, 2007)

Not so much Rolls-Royce as Dr. Stanley Hooker.

Rolls-Royce employed him, not knowing what he could do – and neither did he. It was extremely fortunate that all his previous pure research equipped him to become probably the world’s leading expert on supercharging.

I believe that first and foremost, Hooker was a mathematician, his book “Not much of an engineer” seems to be characteristic of his self effacing attitude, and having seen him in a few interviews, he had a sense of humour (not typical in his field of expertise); he once said about Whittles engine, that he was able to build a compressor equal to that of Whittles, several attempts were worse, but he could never better it, high praise from a great man.

Not so much Rolls-Royce as Dr. Stanley Hooker.

Rolls-Royce employed him, not knowing what he could do – and neither did he. It was extremely fortunate that all his previous pure research equipped him to become probably the world’s leading expert on supercharging.

So a one-off, experimental Merlin produced 2,640 hp for 15 minutes… and a one-off, experimental Allison V-1710 produced 2,800 hp.

Not very applicable to what was in the aircraft, but it just shows my point… both engines were very comparable.

Agreed. The essential architecture of Merlin and V-1710 were virtually identical; water-cooled, V-12, 4-valve engines of 27/28 litres capacity…almost everything else is in the supercharging…and Rolls-Royce seem to have been better at it. 😉

…because the production Allison (in the P40 and P51 anyway) was unblown so did not perform anything like the Merlin at medium or high altitude.

You mean lacking a two-stage or turbo supercharger?

The most powerful factory variant was the V-1710-127, designed to produce 2,900 hp at low altitude and 1,550 hp at 29,000 feet. This engine was static tested at 2,800 hp and was planned for installation in an XP-63H aircraft. The end of the war ended this development, so this promising experiment never flew. The extra power of this version was derived from using exhaust turbines, not to drive a turbosupercharger, but to return that energy to turning the crankshaft. This was called a “turbo-compound” arrangement.

All sounds a bit ‘desperate’ to me…I can’t think of a single aircraft that went into production (let alone combat) with the V-1710 after about 1942. What is even more surprising is that the Merlin did so well after the arrival of the Griffon.

I think the V-1710 was only developed further because it was the best way for Allison to contribute to the war effort. Still not bad for an engine that was powering airships in 1931!

Still it all seems a very complicated and expensive way to (or rather failing to) produce 2500-2800hp.

And of course development of this allison variant, continued until 1946, and so in keeping with the title of the thread, “what if”, the war didn’t stop in 1945 it still wouldn’t have been a contender; the plane it was destined for never flew, and, the turbine installation virtually doubled the engines length (so not for the p51 or the p38), and had the war continued into 1946 ,everyone else would have been flying jets.

So a one-off, experimental Merlin produced 2,640 hp for 15 minutes… and a one-off, experimental Allison V-1710 produced 2,800 hp.

Not very applicable to what was in the aircraft, but it just shows my point… both engines were very comparable.

With respect, it doesn’t, because the production Allison (in the P40 and P51 anyway) was unblown so did not perform anything like the Merlin at medium or high altitude. Horses for courses though, in a bigger aircraft, and with its turbo, the Allison was a decent powerplant.

So a one-off, experimental Merlin produced 2,640 hp for 15 minutes… and a one-off, experimental Allison V-1710 produced 2,800 hp.

Not very applicable to what was in the aircraft, but it just shows my point… both engines were very comparable.

from Wikipedia, regarding the ultimate Allison V-1710:

“The most powerful factory variant was the V-1710-127, designed to produce 2,900 hp at low altitude and 1,550 hp at 29,000 feet. This engine was static tested at 2,800 hp and was planned for installation in an XP-63H aircraft. The end of the war ended this development, so this promising experiment never flew. The extra power of this version was derived from using exhaust turbines, not to drive a turbosupercharger, but to return that energy to turning the crankshaft. This was called a “turbo-compound” arrangement.”

gv

Power is nothing without control, what did it handle like?

I’ve absolutely no idea…but there is nothing to suggest that a fighter with a 2300hp radial engine couldn’t outperform a fighter with a 1500hp inline engine after all isn’t that what happened in 1941 when the RAF first encountered the Fw190 (with only a 1600hp engine)?

Later designs with the Centaurus, the Tempest II (2500hp/4050kg) and Sea Fury (24800hp/4190kg), both designed by Hawker would seem to support this theory as would the already mentioned Fw190 (1600hp/3200kg), or other designs such as the F4U (2000hp/4075kg), Ki-100 (1500hp/2540kg) or La (1850hp/2650kg).

Clearly the nations who developed these fighters didn’t think there was much wrong with a big fighter with a big air-cooled radial engine.

There are severall other factors to consider, reliability I have already mentioned, power to weight ratio, fuel consumption, and relative ease of manufacture (and maintenance); sleeve valves certainly pushed the Centaurus down the ranks, in the last 2 catagories.

‘Reliability’ is an extremely difficult thing to quantify. I’ve certainly never seen a direct comparison between any aero-engines of 1939-1945.

Also I don’t suppose the Spitfire pilots of 1941 took much comfort from how ‘unreliable’ the BMW 801 engine of the Fw190 was!

Don’t have appropriate power-to-weight ratios to hand; these are from Wikipedia, but (assuming they are correct) and to give a rough comparison: Centaurus VII 0.94hp/lb, Merlin 61 0.95hp/lb, BMW 801C-2 0.69hp/lb and Sabre V 1.29hp/lb.

Not sure I’d agree about ease of manufacture. One of the claims made (admittedly by the manufacturer) of sleeve-valve engines was that there were far fewer pieces to manufacture with regard to the valve-train. Of course being air-cooled there are no coolant radiators which are very expensive to manufacture (and also extremely vulnerable to combat damage)…and no water-injection either! 😉

Again I’ve not heard of a German Battle-of-Britain pilot taking much comfort from the fact that a Spitfire was much more difficult to manufacture than his Bf109 was!

As for maintenance, again an extremely difficult thing to quantify, but at least a sleeve-valve engine doesn’t have any valve clearances to adjust or coolant to top-up.

Don’t get me wrong, the Merlin was (and is) a great engine, and, for Britain at least, the most important of the war. There are clearly advantages and disadvantages to both designs and each was ‘ahead’ at various points in their development but I think it is a great pity that the Centaurus wasn’t developed as a priority to fulfil the great early potential it had shown.

There are severall other factors to consider, reliability I have already mentioned, power to weight ratio, fuel consumption, and relative ease of manufacture (and maintenance); sleeve valves certainly pushed the Centaurus down the ranks, in the last 2 catagories.

Hardly a level playing field.

Merlin – 27 litres, Centaurus – 53+ litres.

With near enough double the capacity it should have a bit more grunt.

Sorry, thought this was war…not formula three! 😀

Those bloody Germans eh? Turning up in 1941 with the FW 190 with its 42 litre engine…the cheating b’stards! :rolleyes:

Power is nothing without control, what did it handle like?

probably like a 7 ton truck with no rearward visibility!!
but at least it didnt have a Napier Monstrosity up front;)