WW2 Without the Merlin: Options for the British

I'll agree with SR6, the 12Y would be adequate until Germans introduce the Friedrich. So, for 1941 we need something better to propel RAF fighters.Hercules as a prime choice? Twin stage Twin Wasp? Updated Peregrine? C series V-1710?

Well,

Merlin 45-------1230hp at 18,000ft
Herc XI-------- 1510hp at 11,250ft
Herc VI---------1545hp at 15,500ft
R-1830---------1000hp at 19,000ft
1710 C---------1040hp at 14,300ft.

Peregrine needs a 17% increase to get in the game and a 39% increase to equal the Merlin 45. The first may be doable, the second is highly doubtful (think 1500hp Merlin in high gear at 15-18,000ft).

Now you have the weight/drag problem of the Hercules. 1700-1800lbs ( granted the Liquid cooled engines need radiators) and 52in in diameter and British cowlings in 1940-41 were a far cry from ideal. Exhaust thrust from radial engines at this point on time was usually pretty minimal and the Hercules, with it's exhaust ports halfway down the cylinder is going to be harder (not impossible ) to arrange.





The early units used the leading edge of cowl as a collector ring.



The exhaust from a Merlin XX could be worth around 120hp to a Hurricane II.

Shortround6 said:

Well,

Merlin 45-------1230hp at 18,000ft
Herc XI-------- 1510hp at 11,250ft
Herc VI---------1545hp at 15,500ft
R-1830---------1000hp at 19,000ft
1710 C---------1040hp at 14,300ft.

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The two stage Twin Wasp might not even be available to the British until some time in 1942, judging by the variety of engines Grumman had installed in Wildcat?
The 1710 'C' is in the ballpark with DB-601A/Aa and Merlin III (though we might never know just how much power was the V-1710 'C' able to make when over-boosted at lower altitudes, and the external spur reduction gear was an obstacle on it's own for anything above 1200 HP?). My proposed 'Spitfire replacement' should be able to perform as good as MC.202/Spit V/Bf-109F0-1-2/Ki-61?

Peregrine needs a 17% increase to get in the game and a 39% increase to equal the Merlin 45. The first may be doable, the second is highly doubtful (think 1500hp Merlin in high gear at 15-18,000ft).

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Even if we don't have Merlin, mr. Hooker is still at RR For the 39% increase in Peregrine's power, we need two stage supercharger, and that's not the 1941 stuff. The 17% increase brings us to 1030 HP at, presumably, 18000 ft, once Hooker gets it's job done?

Now you have the weight/drag problem of the Hercules. 1700-1800lbs ( granted the Liquid cooled engines need radiators) and 52in in diameter and British cowlings in 1940-41 were a far cry from ideal. Exhaust thrust from radial engines at this point on time was usually pretty minimal and the Hercules, with it's exhaust ports halfway down the cylinder is going to be harder (not impossible ) to arrange.

The early units used the leading edge of cowl as a collector ring.
The exhaust from a Merlin XX could be worth around 120hp to a Hurricane II.

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Thanks for the feedback. The 'Hurricane replacement' with Hercules, combined with 200-210 sq ft wing makes it an useful fighter-bomber. It should also out climb many of other fighters - useful (not only) once Japan attacks?

tomo pauk said:

The two stage Twin Wasp might not even be available to the British until some time in 1942, judging by the variety of engines Grumman had installed in Wildcat?

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You may be right. 98 two stage engines delivered in 1940, 507 in 1941 (over 5,000 single stage engines) and 2,129 in 1942 (over 8,000 single stage by P&W alone). earlier tooling of a 2nd factory? The licencee factories never built the 2 stage version.

My proposed 'Spitfire replacement' should be able to perform as good as MC.202/Spit V/Bf-109F0-1-2/Ki-61?

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Using what for armament? Using historical armament (20mm Hispano, .50 cal Browning is iffy, or .303 Brownings) you have a problem, no center line cannon means you need two minimum and 1040hp (or even 1200 using over boost) isn't enough. Now you are down to 2-4 .50s (un-historic for the British at this time but plausible) or mix or a 6-8 gun .303 battery. By 1941 the .303 battery is slipping in the ETO even if adequate in other theaters.

Even if we don't have Merlin, mr. Hooker is still at RR For the 39% increase in Peregrine's power, we need two stage supercharger, and that's not the 1941 stuff. The 17% increase brings us to 1030 HP at, presumably, 18000 ft, once Hooker gets it's job done?

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And you are 100-200hp down on the 109F?
A 2000hp Whirlwind makes a nice replacement for the Typhoon but a 1030hp single engine fighter is not where you want to be in 1941/42.

Thanks for the feedback. The 'Hurricane replacement' with Hercules, combined with 200-210 sq ft wing makes it an useful fighter-bomber. It should also out climb many of other fighters - useful (not only) once Japan attacks?

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Useful fighter bombers are only useful if they have other fighters flying top cover for them. At least some of the success of the Kitti-bombers and Hurri-bombers in NA can be attributed to the Spitfires flying top cover for them. Take away the Spitfires and where are you?

A Hurricane II with a Merlin XX had 1186 hp (both shaft and exhaust ) at 20,000ft and 335mph. A Hercules XI is going to be down to about 1200hp (shaft) at 20,000ft with an unknown exhaust thrust/power.
A Hurricane II with a Merlin XX had 1067 hp (both shaft and exhaust ) at 25,000ft and 330mph. A Hercules XI is going to be down to about 1030hp (shaft) at 25,000ft with an unknown exhaust thrust/power.

Exhaust thrust on those front collector ring engines is going to pretty low.
A Hercules XI is rated at 1325HP at 2500ft max continuous (30 min climb) in low gear. A Merlin XX is rated at 1125hp at 9500ft. Granted while climbing the plane is moving slow and drag isn't quite as important but how much more drag does the Hercules have than a Merlin in a single engine plane? 12-20%?

The Hercules can be used as as substitute if you have to but you are NOT going to pick up much of anything over the Hurricane II or Spitfire in terms of performance ( speed/climb/ load carrying ability) in an all round airplane.

Shortround6 said:

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Using what for armament? Using historical armament (20mm Hispano, .50 cal Browning is iffy, or .303 Brownings) you have a problem, no center line cannon means you need two minimum and 1040hp (or even 1200 using over boost) isn't enough. Now you are down to 2-4 .50s (un-historic for the British at this time but plausible) or mix or a 6-8 gun .303 battery. By 1941 the .303 battery is slipping in the ETO even if adequate in other theaters.

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Agreed, 2 cannons and 4 LMGs seem like a hefty weapon pack, comparable with US '1200 HP fighters' (F4F-4, P-39, P-40E) were carrying; fuel carried is far less, as is the fighter's size - keeping weight and drag lower than those had. The weaponry is, however, lighter than what Hurricane IIC was carrying, granted on more HP, but also on a draggy airframe. It would be, though, not an easy task to pack that sort of battery into 180 sq ft wing (Hurricane replacement might be a better platform for that).

And you are 100-200hp down on the 109F?

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I've specified F-0, F-1 and F-2 (DB-601N), and those were featuring some 1050-1060 HP at 18000 ft (1 minute rating), 1250 HP at 6800 ft (same rating). That would be a maybe 50-100 HP deficit, if the upgraded Peregrine is to have 80% HP of the Merlin XX/45; such a Peregrine being able to make full boost for 5 minutes instead of 1 min for the 601N? Smaller size weight of the 'replacement' fighters (vs. historical ones) again should play it's part, performance-wise.

A 2000hp Whirlwind makes a nice replacement for the Typhoon but a 1030hp single engine fighter is not where you want to be in 1941/42.

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Depends what part of 1941/42 we talk about, what fighter we talk about, and what is the altitude those 1030 HP are achieved. Once F-4 arrives (summer of 1941), RAF indeed needs a true performer, as historically. Even more emphasized once Fw-190 arrives, and finally when the F-4's engine is cleared for Notleistung (Feb 1942?). If the RAF's fighter has 1500 HP, but can do only 350-380 MPH, the RAF is, as historically, in great jeopardy. The V-1710 'C's 1040 HP at 14300 ft are worth less than other V-12s 1030 HP at 18000 ft (size weight being comparable).
Hopefully the RAF will, by late 1941/early 1942 field a fighter with Griffon, or Vulture; the 2000 HP Whirly making 380 MPH? RAF actually fields turbo P-38? Historically, the RAF did not have had parity in performance from summer of 1941 till summer of 1942 anyway.

Useful fighter bombers are only useful if they have other fighters flying top cover for them. At least some of the success of the Kitti-bombers and Hurri-bombers in NA can be attributed to the Spitfires flying top cover for them. Take away the Spitfires and where are you?

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We should have the equivalents of MC.202 around. Spitfire arrived in Africa when much of the mauling was over, though - Hurricanes and P-40s were on their own some 2 years.

A Hurricane II with a Merlin XX had 1186 hp (both shaft and exhaust ) at 20,000ft and 335mph. A Hercules XI is going to be down to about 1200hp (shaft) at 20,000ft with an unknown exhaust thrust/power.
A Hurricane II with a Merlin XX had 1067 hp (both shaft and exhaust ) at 25,000ft and 330mph. A Hercules XI is going to be down to about 1030hp (shaft) at 25,000ft with an unknown exhaust thrust/power.

Exhaust thrust on those front collector ring engines is going to pretty low.
A Hercules XI is rated at 1325HP at 2500ft max continuous (30 min climb) in low gear. A Merlin XX is rated at 1125hp at 9500ft. Granted while climbing the plane is moving slow and drag isn't quite as important but how much more drag does the Hercules have than a Merlin in a single engine plane? 12-20%?

The Hercules can be used as as substitute if you have to but you are NOT going to pick up much of anything over the Hurricane II or Spitfire in terms of performance ( speed/climb/ load carrying ability) in an all round airplane.

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Many thanks for the numbers. Just equaling what Hurricane and Spitfire were able to do, but now with Merlin out of picture, is a task on it's own. I was thinking more of a bomb-carrying ability of the fighter with Hercules aboard, especially vs. historical Spitfire and P-40 - eg. the Re.2002 (1175 HP engine) was able to carry 1400 lbs of bombs.

Shortround6 said:

Klimov got a bit of extra life out of the 12Y by reducing the bore, adding several hundred pounds, changing the cylinder heads, using a 2 speed supercharger with a low gear to allow more power at low altitudes ( he didn't improve power at 4-5000 meters that much) and over revving the engine and accepting a much shorter time between overhauls.

The 12Y was designed a number of years before the Merlin ( 12Y was on sale in 1932) and was NEVER intended to run at the BMEP level of a Merlin or Allison or DB 601 even on 87 octane fuel.

It would put fighters in the air but without an extensive redesign ( and lighter armament than the British planes carried) you are putting up targets, not viable fighters.

The BEST production Hispano (not Prototype) was the 12-Y-51 and if offered 1100hp for take off and 1000hp at 3260 meters (10,760ft), with little or no possible improvement by using 100 octane fuel. The Swiss built YS-2 engine used a crankshaft that was about 30kg heavier than the one on the 12-Y-51.
And the 12-Y-51 used bigger intake valves, stronger camshafts and reinforced upper and lower crankcases compared to the -45 and 49 models.

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An Hispano given to Rolls-Royce and redesigned and adapted to using R-R alloys, manufacturing techniques and supercharger technology would probably have performed a great deal better than the Klimovs, which didn't have the R-R metallurgy backing them. The two stage R-R supercharger used on the Merlin was an adaptation of a French Farman design, so there's probably no good reason why it couldn't have been used on a R-R 12Y.

One thing people are forgetting is that the French aviation industry was inefficient and in a great deal of trouble during the 1930s, which is another reason for the 12Y's patchy development and production.

Aozora said:

An Hispano given to Rolls-Royce and redesigned and adapted to using R-R alloys, manufacturing techniques and supercharger technology would probably have performed a great deal better than the Klimovs, which didn't have the R-R metallurgy backing them. The two stage R-R supercharger used on the Merlin was an adaptation of a French Farman design, so there's probably no good reason why it couldn't have been used on a R-R 12Y.

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The Farman bit is the supercharger 2 speed gear drive.

A Merlin type supercharger precludes a motor cannon - because it is in the way.

Aozora said:

An Hispano given to Rolls-Royce and redesigned and adapted to using R-R alloys, manufacturing techniques and supercharger technology would probably have performed a great deal better than the Klimovs, which didn't have the R-R metallurgy backing them. The two stage R-R supercharger used on the Merlin was an adaptation of a French Farman design, so there's probably no good reason why it couldn't have been used on a R-R 12Y.

One thing people are forgetting is that the French aviation industry was inefficient and in a great deal of trouble during the 1930s, which is another reason for the 12Y's patchy development and production.

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The 12Y was an old engine. The cylinder head/valve train design is little different than the WW I V-8s. It is not just metallurgy, The 12Y was very close to a Griffon in displacement (or a Buzzard) but was several hundred pounds lighter than a Merlin, in fact it was about the weight of Peregrine. Given that fact I doubt very highly that R-R Metallurgy can make a 36 liter engine for the same weight as a their own 21 liter engine and have any reserve of strength.

All you are going to "save" from the Hispano is the V-12 60 degree layout. EVERYTHING else needs to be changed.

Using the 12Y ONLY makes sense if you already have one or more factories already tooled up for it. Then you are trying to save your tooling investment and time to retool (lost production).

Rolls already has some minimal tooling for the Buzzard and "R" racing engines. It is an engine with more potential and they know an awful lot more about it.

Shortround6 said:

The 12Y was an old engine. The cylinder head/valve train design is little different than the WW I V-8s. It is not just metallurgy, The 12Y was very close to a Griffon in displacement (or a Buzzard) but was several hundred pounds lighter than a Merlin, in fact it was about the weight of Peregrine. Given that fact I doubt very highly that R-R Metallurgy can make a 36 liter engine for the same weight as a their own 21 liter engine and have any reserve of strength.

All you are going to "save" from the Hispano is the V-12 60 degree layout. EVERYTHING else needs to be changed.

Using the 12Y ONLY makes sense if you already have one or more factories already tooled up for it. Then you are trying to save your tooling investment and time to retool (lost production).

Rolls already has some minimal tooling for the Buzzard and "R" racing engines. It is an engine with more potential and they know an awful lot more about it.

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I doubt if R-R would have bothered redesigning a foreign engine anyway...just some thoughts as to how the 12Y might have been better with R-R type metallurgy. As it is I doubt whether Rolls-Royce would have given up on the idea of designing a decent V-12, even if the Merlin had failed for whatever reason, and chances are what became the Griffon would have emerged earlier than it did, most likely as an extrapolation of the R or Buzzard series updated and improved in much the same way the Kestrel evolved into the Peregrine. Just imagining a Spitfire with (say) 1,500 hp, and developing c. 1,800 hp up to 10,000 ft with increased boost and 100 Octane in 1939 - 1940...

I'm a little bit puzzled about the Buzzard - Wikipedia says it was an '800 HP engine', however there were some 100 examples produced that were capable for ~950 HP, again according to the same source. Any better info?

tomo pauk said:

I'm a little bit puzzled about the Buzzard - Wikipedia says it was an '800 HP engine', however there were some 100 examples produced that were capable for ~950 HP, again according to the same source. Any better info?

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I don't have access to Lumsden at the moment, so I can't give you answers.

It may be that the 800hp was "normal", 950hp for take-off?

In any case, strengthened Buzzards were capable of well over 2000hp. Nearly 3000hp, in fact, in 1931. (Rolls-Royce 'R'.)

tomo pauk said:

I'm a little bit puzzled about the Buzzard - Wikipedia says it was an '800 HP engine', however there were some 100 examples produced that were capable for ~950 HP, again according to the same source. Any better info?

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It was about 800hp at 2000rpm and 925-955hp at 2300rpm. FTH was about 5,000ft. These engines used fixed pitch props so the 800hp is sort of a max cruise power level. Engine was also rated on 70-77 octane fuel. Weight may have been a bit over 1500lbs rather than the number Wiki gives.

Lumsden gives:

Buzzard IMS - 825hp @2000rpm t/o. 955hp @ 2300rpm @ 2000ft

Weight 1540lbs.

Rolls-Royce R (1929) - 1900hp @ 3000rpm, +13.5psi boost t/o / sea level. Weight 1530lb.
Rolls-Royce R (1931) - 2350hp @ 3200rpm, +17.5psi boost t/o / sea level. Weight 1640lb.
Rolls-Royce R (1931 record) - 2530hp @ 3200rpm, +17.6psi boost t/o / sea level. Weight 1640lb.

That was on special fuel, obviously, allowing for the increased boost. But it would seem that the ultimate version of the R was only 100lbs heavier than the base Buzzard. But was capable of taking boost in excess of +18psi and rev to 3400rpm (in later uses). So it should take +12psi with 100 octane fuel comfortably, but the revs would have to be dialled back for longevity. I could see it make 1hp/lb by the BoB.

Many thanks for the feedback.
Some strengthening and a good supercharger needed for 1939-41?

Depends on how much of the "R" you use. The "R" being basically a reinforced/modified Buzzard with a BIG wacking supercharger on it.



A 1939 supercharger may be better than the 1930-31 supercharger even before Hooker gets to it.

Please note the Buzzard was being listed in Nov 1930 Flight Magazine at 662KG dry weight.

Thanks again.
Buzzard seem like a potentially outstanding and timely tank engine - plenty of torque from a 36.7 liter engine? The known diesel V-2 (V12 cylinders, of course) engine from Soviet Union was just a tad bigger, 38.8L.

If the British had wanted a tank engine they could (and did) do much worse than just using the Kestrel. 21.2 liters compared to the 21.35 liters in the Early Tigers and 23.01 in the later Tigers, Panthers and Royal Tigers.

It may have been a bit expensive but it would not be lacking in power right up until the Centurion (and even then?)

Shortround6 said:

Depends on how much of the "R" you use. The "R" being basically a reinforced/modified Buzzard with a BIG wacking supercharger on it.

View attachment 242507

A 1939 supercharger may be better than the 1930-31 supercharger even before Hooker gets to it.

Please note the Buzzard was being listed in Nov 1930 Flight Magazine at 662KG dry weight.

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The Merlin II was listed at 605 kg dry (1,335 lbs) in 1937, so a Buzzard variant with Kestrel/Merlin type refinements would probably have a better power-weight ratio than the original design, depending on the supercharger. R-R already had two speed superchargers in 1938

View attachment Rolls-Royce Merlin 1937.pdf

Had the Buzzard/R series been seriously pursued Rolls-Royce might have been able to ditch the Vulture, and the Avro Manchester might have had more powerful, reliable engines right from the start - a Manchester with two-stage, two-speed supercharged Buzzard variants. Better still a Manchester variant with four two-stage, two speed Buzzard variants...
View attachment Rolls-Royce R Oct 1931.pdf

Oh I will stick by my original argument. Britain would have fallen (or more likely the upper classes would have kicked out Churchill and made a deal).
Britain would have had a 'special relationship' with Germany. British troops would have fought against the Soviets alongside it's 'natural allies' Germany.
Until a bitter stalemate. And a deal with a split between the respective empires.

But the German empire with all of Western Europe and a lot of eastern Europe would have ended up a superpower. The US would have won a bit of the Pacific war, because the British were on the side of the other 'Axis' member, Japan (at the price of losing some of its Empire .. sorry Australia).

Germany would have gotten all the nuclear, radar, etc stuff from Britain (without the Tube Alloy project there would have been no Manhatten one).

British ships (and subs) would have joined into 'isolating' the US, given the USN's hate (at that time and now) of anti sub stuff. then its Pacific war against Japan would have died real fast.
Without the technical stuff from Britain the US remained a .. great place to make a good refrigerator.
No radar, no nuke stuff, no jet engines ... and so on.

A totering balance would have been struck until the US invades Canada (post Roosevelt) and the Axis supports it with troops. The US reels against that attack, well planned. British' shock troops' thrust towards Washington (at the cheers of many Americans no less). LiftwafeRAF (new name for the combined Luftwaffe and the RAF) combined airpower strikes deep into the US. Under the new Doctrine of 'lie to the indigenous until you have won .. then exterminate them later', a British innovation to Axis planning, German, Italian (though not Irish or Jewish) Americans flock to the cause of being 'liberated'. This is a war of 'liberation 'from 'plutocrats'.

The US North falls, aided by long term deals with the American 'South', promised total control of their areas and their 'race issues' and 'promises to 'help' them expand' further south.

Wall Street is untouched since it, as always, funds all of them. Though New York, for many, especially the rich, becomes better (unless you were Irish, Jewish, homosexual, etc in which case it becomes a lot, lot worse).


And then, the rump of the Soviets, basically the pure Russians, when the Axis is so stretched.. attack, starting with massive nuclear attacks on Berlin, Paris, London and the Russians sweep though the near east and into the (totally undefended) Germany and western Europe.

In the end a smashed, destroyed (and very glowing) World (you could sit on Mars and look at it .. wow it is bright, even without sunlight).

And all because there was no Merlin engine.......8)

There were alternatives to the Merlin which could have powered fighters in the battle of Britain.

For sure.

And win. ..but as good as the merlin is the question