WW2 Without the Merlin: Options for the British

There is no question the absence of a Merlin would have been a great loss for the British war effort. Except if the resources poured into the merlinhad been diverted into other engine projects and tangible results obtained to compensate for the non-development of the merlin.

This scenario then means we have to estimate how much effort (even design resources constitute a finte resource, difficult to quantify, but finite just the same) would be released if the Merlin was not developed.

If the scenario is re-defined, such that resources are poured into the merlin, and such efforts are a failure, then Britain's war making potential sufferes a major setback.

The parameters of the scenario need to be more sharply defined....are we looking at a failed design efort, or a design effort never attempted?????

On the assumption that a design effort is never attempted, and that resources are instead poured into other projects, then one has to assume that from the gaggle of protoypes that werent developed because the Merlin was a success

Thinking out of the box, I dont see it as all that difficult to envisage a development of something like the Britol Mercury along the same lines as the P&W R1340 Single Wasp was developed. The American engine served as a the basis for the R1830 twin Wasp, and was more or less a contemporary of the Bristol engine. In fact a comparison of the two is worth undertaking

The R1340 had the following chracteristics (from Wiki)

Type: Nine-cylinder single-row supercharged air-cooled radial engine
Bore: 5.75 in (146 mm)
Stroke: 5.75 in (146 mm)
Displacement: 1,344 in3 (22 L)
Diameter: 51.75 in (1.314 m)
Dry weight: 930 lb (422 kg)

Performance
Power output: 600 hp (447 kW) at 2,250 rpm at 6,200 ft (1,890 m)
Specific power: 0.45 hp/in³ (20.3 kW/L)
Compression ratio: 6:1
Power-to-weight ratio: 0.65 hp/lb (1.05 kW/kg)

It was developed into into the R1830 twin Wasp. which started as a 750hp engine, but by 1939 had been developed into an engine capable of 1200hp. It eventually was uprated to deliver 1350hp. Both respectable power outputs

Wiki gives the following characteristics for the Twin Wasp

Type: Fourteen-cylinder two-row supercharged air-cooled radial engine
Bore: 5.5 in (139.7 mm)
Stroke: 5.5 in (139.7 mm)
Displacement: 1,829.4 in³ (30 l)
Length: 59.06 in (1,500 mm)
Diameter: 48.03 in (1,220 mm)
Dry weight: 1,250 lb (567 kg)

Performance
Power output:
1,200 hp (895 kW) at 2,700 rpm for takeoff
700 hp (522 kW) at 2,325 rpm cruise power at 13,120 ft (4,000 m)

Specific power: 0.66 hp/in³ (29.83 kW/l)
Compression ratio: 6.7:1
Specific fuel consumption: 0.49 lb/(hp•h) (295 g/(kW•h))
Power-to-weight ratio: 0.96 hp/lb (1.58 kW/kg)

The Bristol Mercury has characteristics remarkably similar to the Single Wasp in its key feratures....weight, dimensions, and power output.

The design development of the Bristol Mercury was the Hercules. The Hercules was again a remarkable equivalent of the twin Wasp, if somewhat less reliable (more correctly, it was a development of the Bristol Perseus sleeve valve configuration). I can easily envisage, with more resources spent on its development, acting as a very reliable, somewhat uprated version and adequate substitute for the Merlin in the early war period.

For the later war, if additional resources were made available by the non-development of the Merlin, I see the long term engine needs of the British being met by the Bristol Centaurus. This engine, like all the Bristol interwar engines, has a link back to the Jupiter of 1919.

The Centaurus was type tested in 1938 but production was not started for two reasons....it suffered some reliability issues, and quite simply, early in the war it was not needed. Production did not start until 1942 mostly because priority was given to the more useful Hercules and as stated the need to improve the reliability of the entire engine line. Nor was there any real need for the larger engine at this early point in the war, when most military aircraft designs were intended to mount engines of 1,000 hp or a little more. The Hercules' approximately 1,500 hp was simply better suited to the existing airframes then in production.

Provided we are not talking about a total failure of the merlin program (ie, it was never attempted, rather than attempted, but failed), there are plenty of alternatives available to the British.

The problem for fighters is the difference in drag between the liquid cooled v-12 and the air-cooled radial. This difference changed as time went on. The P-36 (with a Twin Wasp, Double Wasp was the R-2800) had 22% more drag than the XP-40. By the fall of 1942 P &W had gotten the difference down to 8%. By the end of the war who knows?

Bombers, with their fat fuselages, multiple engine nacelles, fat wings and projecting turrets have a much lower percentage of total drag caused by the engine installations.

One reason for the dominance of the Merlin on the early war British aircraft scene was the near failure of the Hercules to make it into production.

Bristol built their first sleeve valve test rig in 1926-7, design work started on the Pereus in 1932. While hand built (or hand finished) engines built in small numbers worked OK, manufacturing sleeves in quantity was a stumbling block that was only solved at the last minute and then, as the story goes, by accident. A worker used grinding wheels out of sequence.
No fault in the design of the engine, like under sized bearings or a harmonic vibration but a major production obstacle. And one that the solution to was counter intuitive to knowledge at the time.

Bristol superchargers were somewhat less than stellar also, despite their setting a world altitude record with a two stage Pegasus in 1938.

Rolls Royce would much more likely have spent their resources on other Rolls Royce engines rather than working on Bristol engines in the years from 1932 to 1938-39 in the absence of the Merlin.

Don't get me wrong, The Hercules was a good engine and got better as the war went on, the post war 100 series and higher were very good engine indeed but are a bit late. But the hercules was also a bit late in the 1930s and was NOT avialable for the thousands of aircraft powered by Merlins from 1936-1940. Granted the British might have gotten by without quite as many Battles and Defiants

Looking at speed figures for the French fighters with Hispano 12Y engine, the MS-406 ends up as a really slow airplane. Not surprisingly, it was lacking ejector (rear facing) exhaust stacks - that alone making 10-15 mph difference in speed here? Swiss license-built examples received ejector exhaust stacks in 1944.

The Napier Dagger would be another interesting, but controversial choice, to power RAF planes between 1939-41?

Could be. Could aslo be the Ms 406 was kind of high drag. Could also be that the engine used in the 406 had a FTH of 3250 meters (860hp), or 1674 meters lower than a Merlin III. The engine in the D 520 had a FTH of 4200 meters (920hp). The HP difference isn't that great but the difference in altitude means that the air is about 6-7% thinner for lower drag.

The Dagger is a terriable choice. It's FTH was 8,750ft (2650 meters). It's 1000hp will drop to less than the Peregrines 885hp at 15,000ft.

All it needs is better cooling, a better supercharger, less drag, and...........
It is a 16.9 liter engine running at 4200rpm full throttle. 48 spark plugs to change.

Shortround6 said:

Could be. Could aslo be the Ms 406 was kind of high drag. Could also be that the engine used in the 406 had a FTH of 3250 meters (860hp), or 1674 meters lower than a Merlin III. The engine in the D 520 had a FTH of 4200 meters (920hp). The HP difference isn't that great but the difference in altitude means that the air is about 6-7% thinner for lower drag.

Click to expand...

Many thanks for pointing out the difference between FTHs.
The quick overview of the Hispano variants can be seen here, and more detailed data is in our 'Engines' subforum - many thanks to siboh who provided it. The 406 used the 12Y-31 variant, the D.520 used the 12Y-45.

The Dagger is a terriable choice. It's FTH was 8,750ft (2650 meters). It's 1000hp will drop to less than the Peregrines 885hp at 15,000ft.

All it needs is better cooling, a better supercharger, less drag, and...........
It is a 16.9 liter engine running at 4200rpm full throttle. 48 spark plugs to change.

Click to expand...

Not an easy task, filling Merlin's shoes

The problem with asking these sort of questions (thought experiments) is that you have to go through the details. Like WHY there would be no Merlin.
It was a logical development of previous engines (inspired by Royce himself and ordered by him to make it, hence the PV tag .. Private Venture they used their own money at first and they were not a rich company at that time by any means), brought to life by the great Hives.

So for it not to be available then something (ah lah the Allison 1710, 10 years of development) had to go seriously wrong within RR. They had to go broke, or Royce died earlier, or Hives was never in the company ... or whatever. Given their technical ability (and the Merlin only took 4 years to get into full production and RR had fought for the 'shadow' factories right from the beginning) then to have a zero Merlin scenario you basically have to assume RR went bust some years before.

But the lack of it (to be serious for a moment) meant there would be no Spit or Hurricane or Mossie or Merlin Mustang, at least as we know them. In the case of the first three their designs were built around the Merlin. For the Spit and Hurri it was an official requirement.

If for some reason they couldn't do the Merlin, then the Griffon has to be assumed as a dead duck too (basically RR is gone). And their earlier engines as well. Therefore the British only have, in the big engine league of the time, the Bristol ones. Given how long it took them to get the Hercules into production (and it was always a low altitude engine), then you can quite sincerely say that the British lose the BoB, in fact they will surrender before then as they have no aircraft that can even get close to the 109/DB 601 in performance. Whatever they put in the air will be slaughtered and the Luftwaffe can bomb Britain (even if it does not invade) into total submission in the day.

Now you have no US involvement in the European war, even if they wanted too how could they? Worse, there is no way to predict the outcomes of the British/German peace treaty. Maybe the RN does agree to defend Germany???

The Merlin is one of those cardinal points (in Dr Who terms a 'fixed point in time') . While many different things could have happened or been done in WW2 and had little effect on the eventual outcome certain things are 'fixed', without which there are zero options and the whole outcome can change.

The classic is, what if Roosevelt had left MacArthur in the Philippines .. some would argue the US would have won the Pacific war earlier, at the very least it would have made zero difference.

WW2 was winnable by the Germans, though Hitler would have had to be killed to achieve it post France. The Allies won by a slim margin, much slimmer than most people realise. If Hitler hadn't been distracted by Greece and the Balkans and invaded the USSR a month earlier (as planned) then...?.

If the Germans had done the, correct, south thrust first, the Med, North Africa. Middle East, Iraq and Iranian oil and an another springboard for an attack at the USSR later, Britain surrenders, the US is powerless, the USSR later (with Germany with all that oil) is attacked from multiple thrusts .. game over.

All those are 'what if's' are interesting, as is the other one, what of the British had consolidated, forgot about Greece and kicked the Italians out of NA, then the Med would have remained a British 'lake' and many, many shipping issues would never have happened and the Western Allied invasion of France could have happened in 43 (because of shipping it was impossible).


But the Merlin is one of those cardinal points. There literally is no alternative, not if you want a Spit or Hurri in 1940.

Funny thing these cardinal points, applies to people too. Take out Dowding or Park then the war is lost as well. No Dowding, no FC, no radar network, C&C and Spits/Hurris (or with 8 guns).
No Park, the Bob is lost in a couple of weeks.
No Mitchell and no Spit.
No Royce or Hives and no Merlin.
No Merlin and no Spit, Hurri, Mosquito, or Lancaster.
No Merlin (or even RR push, they disobeyed the Air Ministry which had, thanks to Portal, zero interest) and no Merlin Mustang.

The old 'For a want of a nail ...' argument.

You are assuming that the rest of the British aero engine industry does nothing different.
While the Air Ministry discouraged Fairey from becomeing an engine manufacturer that was with Rolls in existance. It was Fairey's importation of the Curtiss V-12 that got the AIr Ministry to ask Rolls for something better, the Kestrel.
A J Rowledge, who had designed the Napier Lion went to Rolls Royce in 1921 (?) contributed quite a bit to most Rolls-Royce pison engines from the Condor on. No Rolls-Royce, does he retire to the south of France?
Halford had taken over as chief designer at Napier ( actual an indepentent contractor for quite a few years) by the Very early 30s.

IF the Air Ministry had issued a reqirement for a liquid cooled V-12 something would have been built by another company than Rolls Royce and given the improtance of the liquid cooled V-12 that requirement would have been made either in the 1920s or shortly after the R-R bankrupcy in your scenerio. It wouldn't be a Merlin but it would be something.

With every major country in the aircraft industry making one or more V-12s (the US in the 20s had 2 different sized Curtiss and two diffierent sized Packards) the idea that Britian would ignore that type of engine without Rolls Royce doesn't hold up.

The problem for fighters is the difference in drag between the liquid cooled v-12 and the air-cooled radial. This difference changed as time went on. The P-36 (with a Twin Wasp, Double Wasp was the R-2800) had 22% more drag than the XP-40. By the fall of 1942 P &W had gotten the difference down to 8%. By the end of the war who knows?

Click to expand...

No argument that a radial was more draggy than an inline, and the designs around which the aircraft for which the merlin was designed were about as good as they were in the 1930s as far as reducing drag was concerned.

Thanks for the correction about Double wasp and twin wasp. i did know, but suffereed some sort of brain melt down when i wrote my original post.

One reason for the dominance of the Merlin on the early war British aircraft scene was the near failure of the Hercules to make it into production.

Bristol built their first sleeve valve test rig in 1926-7, design work started on the Pereus in 1932. While hand built (or hand finished) engines built in small numbers worked OK, manufacturing sleeves in quantity was a stumbling block that was only solved at the last minute and then, as the story goes, by accident. A worker used grinding wheels out of sequence.

Click to expand...

I have no problem in describing the hercules as problematic. Its the main reason the Australians settled firstly on the single wasp for their licence built engines at the GAF works, and then the twin wasp from 1941. The reason the Australians switched to the American engines was that the hercules that they planned to build under licence for their beaforts was not ready for production in 1939, and then the British slapped their emargo on technology from 1939. Australia was already making single wasps in 1939, faced with the British embargo the GAF retooled in 1940 to build the twin wasp and rolled the first twin wasps out by May 1941. they had converted their factory in less than twelve months with virtually no expereience to call on, and not much in the way of investment either.

If more money had been poured into the finishing of the hercules, i dont see any reason why its bugs could not have been ironed out 1936-7 when they were supposed to. i get the near miraculous way the solution to the sleeve valve problems were solved, but in reality thet merely confirms that the design was suffering from a lack of investment and proper R&D. All clear inidications of not enough money. more money means a more thorough development, means an earlier completion of the design, means earlier entry into quantity production. Same applies to the Centaurus, which suffered similar problems really

No fault in the design of the engine, like under sized bearings or a harmonic vibration but a major production obstacle. And one that the solution to was counter intuitive to knowledge at the time.

Click to expand...

But surely you would agree, if more money had been available for the development of this engine, these issues could have been solved far earlier.

Bristol superchargers were somewhat less than stellar also, despite their setting a world altitude record with a two stage Pegasus in 1938.

Click to expand...

Ive read about this as well, and accept that it was a bit of a problem. What I dont know, is the precise nature of these problems. I dont suppose yopu have any knowledge you would like to share. I would be very interested to know.

Rolls Royce would much more likely have spent their resources on other Rolls Royce engines rather than working on Bristol engines in the years from 1932 to 1938-39 in the absence of the Merlin.

Click to expand...

I agree entirely, but its here we have to get creative as to why the Merlin would not be designed or developed. There are not a lot of options, and all of them are really quite "out there" as far as plausibility is concerned. one might be that Rolls royce was bought out by one or more of its rivals. The only way I can see the Merlin not being produced, is if there is no RR to build it. in that scenario, where does the RR expertise go....to its rivals of course....the engineers would be dispersed to these other companies as required. Bristols R&D capability gets bigger, because there is no RR R&D team.....

Don't get me wrong, The Hercules was a good engine and got better as the war went on, the post war 100 series and higher were very good engine indeed but are a bit late. But the hercules was also a bit late in the 1930s and was NOT avialable for the thousands of aircraft powered by Merlins from 1936-1940. Granted the British might have gotten by without quite as many Battles and Defiants

Click to expand...

The Herc was not abvail;able because it wasnt ready, and it wasnt ready because it had insufficient R&D poured into it. It could have, if the effort poured into the merlin was put into it instead. There is no reason to surmise otherwise. as you say, there was nothing inherently wrong with the design.

The question then arises, what sort of design would be built around the Hercules. Probably not a Spitfire or hurricane. possible a development of Spec F5/34. This design had just 840 HP when designed, had more range than a Hurricane, could climb faster and a top speed of 316 mph. Obviously it would lose some of this performance when kitted out to combat requirements, but what could the design have done with a 1200 hp donk instead.

Bristol spent around 2 million pounds and 5 years on the sleeve valve project to get a workable engine, the Perseus. The initial R-2800 (A series) may have cost 8 million dollars.

The Hercules started with a sand cast single piece cylinder head with 540in2 and was changed to a die cast single piece cylinder head with 581in2 by the first production model. The main war time models used two piece heads, die cast for at least one part, with 728in2 of cooling area. Improved casting technique allowed an increase to 777in2 and a reduction of of 15 degrees C in CHT. Several more head designs were tried and finished, post war, with a machined copper based head.
This is one example of the development and this piece of the engine had no moving parts.
Literally hundreds of combinations of alloys and finishing proccess had been tried before the "solution" was discovered. Please note the trouble Napair had with sleeve valves before Bristol was "persuaded" to share their knowledge ( Taurus sleeves) with , again, hundreds of combinations of materials and finishing processes. How many were duplicates I don't know.
The sleeve valve came very close to bankrupting Bristol.

I don't know what the Problem was with Bristol superchargers but I believe when Stanley Hooker left Rolls-Royce and went to Bristol he is supposed to have thought that the Bristol designers didn't really understand airflow. Granted they were working on jets at the time but in 1949 a great many of the men involved had worked on the wartime piston engines.
A good supercharger needs 3 things, mass airflow, pressure ratio (not the same thing) and efficency. Mass airflow is the easy one, just keep making the whole thing bigger. Getting a good pressure ratio at a good efficency is the hard part. Poor efficency even with a good pressure ratio means more power to get the same effect and most of the extra power goes into heating the intake charge which lowers the density/airflow and pushes the intake mixture closer to the detonation limits.

parsifal said:

I agree entirely, but its here we have to get creative as to why the Merlin would not be designed or developed. There are not a lot of options, and all of them are really quite "out there" as far as plausibility is concerned. one might be that Rolls royce was bought out by one or more of its rivals. The only way I can see the Merlin not being produced, is if there is no RR to build it. in that scenario, where does the RR expertise go....to its rivals of course....the engineers would be dispersed to these other companies as required. Bristols R&D capability gets bigger, because there is no RR R&D team.....

Click to expand...

The Merlin did fail. The original design with the "ramp heads" didn't work as well as predicted from single cylinder testing.

At that point Rolls-Royce had three options:

• cancel Merlin development and use the resources on other projects being developed - Peregrine, Vulture and Exe.
• cancel Merlin development and start a new project/ This could be all new, or could be new developments of old engines. eg Buzzard+/production R/Griffon I
• redesign Merlin and make it work

History will show that the third option was chosen. But they could equally have gone in the other directions.

Maybe they could have started again and used their own sleeve valve research (Kestrel RR/P and RR/D) to design a new liquid cooled V-12 of 27-37l.

My memory maybe playing tricks but wasnt the spitfire designed originally for the Goshawk engine?

That woukd suck as the Goshawk was 700bhp and the Spit would have been well rubbish. Stupid evaporative cooling malarkey.

The 1,000bhp merlin alternative would have to be about 1934 so that the Spitfire can be designed and fitted for it. Spitfire is a big old thing for 700 horses. Again the 12Y just fits nicely here and holds the fort for something to appear down the line.

I think that was the Supermarine Type 224 Supermarine Type 224 - Wikipedia, the free encyclopedia

The bent wing? For sure.

But the leading edge of type 300 was designed for evaporative cooling. Sure of it.

Possibly the Merlin was originally to be steam cooled RR and the Air Ministry seemed to be quite keen on it. Pretty sure the Spit was designed around the Merlin possibly some of the early drawings were for a Goshawk/Kestrel sized engine installation. Mitchell seemed to be a great doodler turning out countless iterations of a basic design till it looked right.

The Basket said:

The 1,000bhp merlin alternative would have to be about 1934 so that the Spitfire can be designed and fitted for it. Spitfire is a big old thing for 700 horses. Again the 12Y just fits nicely here and holds the fort for something to appear down the line.

Click to expand...

The 12Y in 1934 was 860hp and even then none too reliable( Russians had it down rated to 750hp). Unless R-R goes bust in 1929-31 they had the Buzzard which gave 800hp MAX continuous on 70-77 octane.

Octane is not a liner scale. the PN (performance number) scale may not be liner either but it is a lot closer.

octane..........70............77...........80............87.........91............100
PN number.....48.28........54.90.......58.33.......68.29......75.68.......100

Feed a Buzzard 87 octane instead of 77 octane and IF (mighty big if) you could raise the manifold pressure with NO increase in temperature you could get about 25% in power from the engine.

Kestrel V would give 640hp at 14,000ft. 740hp at 11,000ft. 745hp for take-off. It was a bit lighter than 1934 12Y.

The Supermarine Type 224 was built to AM specification F7/30. It featured a Kestrel engine and evaporative cooling. It was specifically the Kestrel S, developing 535 bhp at 2500 rpm and 13,000ft. It first flew 20th Feb 1934 and performance was disappointing.

Subsequently the prototype was extensively modified and fitted with a Goshawk engine. The aircraft in this form appeared at the RAF pageant at Hendon on 30th June.

The Air Ministry wrote asking for an alternate proposal for the specification using the Napier Dagger engine. On 6th November Supermarine declined the proposal, officially they thought the Napier powered version would be slower than that with the Goshawk engine. Unofficially Supermarine had a long standing relationship with Rolls Royce and were anticipating the new PV12. This is first mentioned in Supermarine Report TD 1232, dated 13th October, before the AM request for a Dagger engine proposal.

The next proposal from Supermarine was illustrated in design submission 425A and is starting to look like a Spitfire, though without the elliptical wing. This was to be powered by a Goshawk II.

The Type 300 was a result of an on going process and it was decided in December 1934 that it would be powered by the PV12 and retain the evaporative cooling of its predecessors.

On 9th January 1935 Mr Ross of Supermarine visited Rolls Royce in Derby to discuss re-rating the PV12 and agree figures for the fully supercharged version now known as Merlin. This just six days after AM contract 361140/34 which led to the Spitfire.

The Type 300 was designed around the Merlin and Mr Ross' Derby visit also arranged for delivery of the engines to Supermarine for the Type 300 prototype. The figures provided by Rolls Royce to Supermarine in January 1935 for the Merlin engine were; Rated 950 bhp at 2600rpm and 11,000ft. Maximum 1045 bhp at 3000rpm and 15,000ft.

Cheers

Steve

The Basket said:

The bent wing? For sure.

But the leading edge of type 300 was designed for evaporative cooling. Sure of it.

Click to expand...

Definitely: the Merlin was intended to use evaporative cooling and the D shaped wing leading edge was to house the condensers, plus there would be a retractable auxiliary radiator behind the cockpit. This is the design in 1935 (Price The Spitfire Story 2010 p 19):

Shortround6 said:

You are assuming that the rest of the British aero engine industry does nothing different.
While the Air Ministry discouraged Fairey from becomeing an engine manufacturer that was with Rolls in existance. It was Fairey's importation of the Curtiss V-12 that got the AIr Ministry to ask Rolls for something better, the Kestrel.
A J Rowledge, who had designed the Napier Lion went to Rolls Royce in 1921 (?) contributed quite a bit to most Rolls-Royce pison engines from the Condor on. No Rolls-Royce, does he retire to the south of France?
Halford had taken over as chief designer at Napier ( actual an indepentent contractor for quite a few years) by the Very early 30s.

IF the Air Ministry had issued a reqirement for a liquid cooled V-12 something would have been built by another company than Rolls Royce and given the improtance of the liquid cooled V-12 that requirement would have been made either in the 1920s or shortly after the R-R bankrupcy in your scenerio. It wouldn't be a Merlin but it would be something.

With every major country in the aircraft industry making one or more V-12s (the US in the 20s had 2 different sized Curtiss and two diffierent sized Packards) the idea that Britian would ignore that type of engine without Rolls Royce doesn't hold up.

Click to expand...

You make a mistake ... individuals count. Without Royce and Hives (always forgotten about, though he dominated things so much during the war) there is no Merlin. Royce made the decision, Hives made it ... and fought for the 'shadow' factory system so the mass production was in place very early on. Even by 39 RR was producing more Merlins than there were aircraft for it.

None of the other British engines were in place then. None of the others got the same mid/high/very high altitude performance out of their engines. And there is another individual that counts, Hooker. Without his work the Merlin would probably topped out at about the 1,300bph level even with 2 stages, and probably only 600-700bph at 30,000ft, not enough to be competitive against the ever lager, lower supercharged, higher comp ratio, radically cammed, power boosted German engines.

To put it in perspective that would have gotten the Merlin Mustangs into about the 410mph class at 20,000ft, and Spit IXs into about 380. Not nearly enough to hold their own.

The fact that the Merlin was up to 2,000bph in operational use in 44 was amazing (as was the 2,600bph type approved RM-17). The other fact was that the 130's (RM-16s) used in the Hornet were 2,000bhp ... at 20lb boost on 100 grade fuel was also amazing ... as it was, by that time a tiny engine of 'only' 27 litres compared with all the other 33, 36, 42, 56, etc litre engines.

But Hooker was another Hives 'creation', as he admitted himself. A truly 'great man'.

OldSkeptic said:

You make a mistake ... individuals count. Without Royce and Hives (always forgotten about, though he dominated things so much during the war) there is no Merlin. Royce made the decision, Hives made it ... and fought for the 'shadow' factory system so the mass production was in place very early on. Even by 39 RR was producing more Merlins than there were aircraft for it.

None of the other British engines were in place then. None of the others got the same mid/high/very high altitude performance out of their engines. And there is another individual that counts, Hooker. Without his work the Merlin would probably topped out at about the 1,300bph level even with 2 stages, and probably only 600-700bph at 30,000ft, not enough to be competitive against the ever lager, lower supercharged, higher comp ratio, radically cammed, power boosted German engines.

To put it in perspective that would have gotten the Merlin Mustangs into about the 410mph class at 20,000ft, and Spit IXs into about 380. Not nearly enough to hold their own.

The fact that the Merlin was up to 2,000bph in operational use in 44 was amazing (as was the 2,600bph type approved RM-17). The other fact was that the 130's (RM-16s) used in the Hornet were 2,000bhp ... at 20lb boost on 100 grade fuel was also amazing ... as it was, by that time a tiny engine of 'only' 27 litres compared with all the other 33, 36, 42, 56, etc litre engines.

But Hooker was another Hives 'creation', as he admitted himself. A truly 'great man'.

Click to expand...

And Hooker claimed he was "Not Much of an Engineer"...Not Much of an Engineer: Sir Stanley Hooker: 0800165000736: Amazon.com: Books

Here's an article on Merlin development by A.C Lovesey, who also played a role in its development:

http://www.wwiiaircraftperformance.org/merlin-lovesey.pdf

I think this and the V-1710 failure thread are somewhat predicated on the Rolls Royce and Allison engineers and managers being so completely stupid that they run down a blind alley and then try to butt through a thick reinforced concrete wall with their heads. While managers can be ridiculously enamored of failed and flawed projects, especially when somebody else* is footing the bill, they're usually** not stupid.

Looking at the likely points of failure in a quite conventional liquid-cooled V-12s, even in the 1930s, and I think that it's hard to see what potentially insurmountable problems either engine had: poppet valves were well-known technology, with sodium cooled valves already in commercial use, V-12 crankshaft torsional vibration issues were known, if not well understood, the monoblock Curtis D-12 was well known to the engine community, overhead camshafts were commonplace, etc: the Merlin and the V-1710 were not bleading-edge designs, instead, they were advanced designs based on existing practice. Bristol's sleeve valve designs were certainly much riskier, as were Napier's H-engines. Indeed, P&WA's R-2800 and Curtis-Wright's R-3350 were probably riskier developments than the Merlin or the V-1710.


----------------

* Whether the money comes from shareholders or taxpayers, project managers rarely write checks from their own bank accounts.

** They obviously are sometimes. They do, after all, remain human, and stay the course way too long, even endangering company survival. Examples? Convair CV880/CV990 and the Ford Edsel.