WW2 Without the Merlin: Options for the British

[stona]

You mean that the Teutonic übermensch couldn't? Looking at some of the posts here, one would think that the Germans must have won the war because they were so much better at everything.

They could swim across......oh, hang on, Vice Admiral Assman of the German naval staff actually specifically said that they couldn't simply swim over, the defeatist nincompoop
Cheers
Steve

 

[The Basket]

The Hispano Suiza 12Y replace the merlin. Maybe not perfect but adequate. Get 20mm cannon as well

 

[Shortround6]

Adequate for 1940, after that it is a liability.

It needs major re-work just to get to 1200-1300hp below 4000 meters let alone above that.

Rolls, from the end of WW I on, always had 2 engines on offer and often 3. The Merlin was their 6th V-12 production aircraft engine. If had been shown to be a dead end in 1936, they had 2-3 years to come up with something else like the Griffon I.

 

[swampyankee]

They could swim across......oh, hang on, Vice Admiral Assman of the German naval staff actually specifically said that they couldn't simply swim over, the defeatist nincompoop
Cheers
Steve

I thought the plan was for them to march along the bottom of the English Channel. They just couldn't get big enough seahorses for their artillery.

 

[wuzak]

The Hispano Suiza 12Y replace the merlin. Maybe not perfect but adequate. Get 20mm cannon as well

Adequate for 1940, after that it is a liability.

It needs major re-work just to get to 1200-1300hp below 4000 meters let alone above that.

Rolls, from the end of WW I on, always had 2 engines on offer and often 3. The Merlin was their 6th V-12 production aircraft engine. If had been shown to be a dead end in 1936, they had 2-3 years to come up with something else like the Griffon I.

The Buzzard was good for ~800-900hp, at a weight of ~1100-1200lb. It was slightly taller than the Merlin, but otherwise was similar dimensionally.

With a couple of hundred pounds of strengthening it would weigh the same as a production Merlin, and one would think capable of similar power levels.

The R weighed about the same as a 2 stage Merlin ~1650lbs. A detuned R should have been good for at least ~1300-1500hp by 1940, considering in full sprint trim in 1931 it was capable of >2900hp. he interesting thing about the R was that it was able to rev to 3400rpm, whereas the Griffon was stuck at 2750rpm. I suppose that was all about longevity.

 

[tomo pauk]

Wonder if the Peregrine would've went to 3200 rpm, some time mid war? It is not hard to visualise the two speed, 'Hookerised' Peregrine, too. And then a two stage unit. Griffon and Vulture following suit some time in 1943? 2000 HP for Tempest, but at 25000 ft - 470 mph?

The Hurri and Spit 'replacements' getting Hercules (FAA gets those too?) and V-1710 (380-400 mph in 1943?)?

 

[Shortround6]

I like the Peregrine and I like the Whirlwind and think both got a bum rap but sinking too much time or money into the Peregrine is a loosing deal. A two speed Merlin XX type supercharger and a little beefing up is about as far as it should go.

Increasing the RPM is questionable. Maybe it will work and maybe it won't. If you increase the pressure in the cylinders by 10% you should get 10% more power (minus the extra power needed to drive the supercharger) and you may have to strengthen certain parts to handle the 10% increase in strain. If you increase the RPM 10% you increase the strain on the reciprocating and rotating parts by 21%. You increase the friction in the engine by 21% and you do need a bit more power to drive the supercharger to flow 10% more air. Your net power gain is lower than increasing the BMEP 10% and you may need more modifications depending on the original strength of the parts.
If you have another, larger engine in the works ( Buzzard/Griffin) then the research and development of any but the simplest of improvements should go to that engine. A single stage Griffon II was about 73% of the weight of a single stage Vulture (about 650lbs ?) which can certainly affect the size/choice of airframe.

 

[Shortround6]

duplicate post.

 

[tomo pauk]

I like the Peregrine and I like the Whirlwind and think both got a bum rap but sinking too much time or money into the Peregrine is a loosing deal. A two speed Merlin XX type supercharger and a little beefing up is about as far as it should go.

The 'Peregrine XX' making some 940 HP at 18500 ft, 1150 at 11800 ft (12 lbs boost?) in late 1940/early 1941 - comparable with 'plain vanilla' V-1710s (8.8:1 and 9.6:1 superchargers) and DB-601A/Aa/N? Later versions making 150-200 HP more, at lower altitudes of course?

Increasing the RPM is questionable. Maybe it will work and maybe it won't. If you increase the pressure in the cylinders by 10% you should get 10% more power (minus the extra power needed to drive the supercharger) and you may have to strengthen certain parts to handle the 10% increase in strain. If you increase the RPM 10% you increase the strain on the reciprocating and rotating parts by 21%. You increase the friction in the engine by 21% and you do need a bit more power to drive the supercharger to flow 10% more air. Your net power gain is lower than increasing the BMEP 10% and you may need more modifications depending on the original strength of the parts.

Okay, thanks for assessment. The increase in RPM should allow for greater power at all altitudes, vs. greater boost allowing greater power at altitudes under current FTH?

If you have another, larger engine in the works ( Buzzard/Griffin) then the research and development of any but the simplest of improvements should go to that engine. A single stage Griffon II was about 73% of the weight of a single stage Vulture (about 650lbs ?) which can certainly affect the size/choice of airframe.

Again, well put.
Without Merlin around, Supermarine might start their own 'new, 2000+ HP fighter', to compete with Hawker?

 

[The Basket]

Not sure what the issue with the Hispano 12Y as its timeframe is right where you want it and plus you get a 20mm cannon included. It certainly could have put fighters in the air during the Battle of Britian and this is certainly not a 'what if' as it is fully viable. Of course it would be developed to new power ratings to keep up with the latest tech and obviously would be replaced by something better such as the Griffon and Sabre and Hercules in good time.

Klimov got a bit of extra life out the 12Y so it certainly would have been good enough and available.

 

[The Basket]

/

 

[Shortround6]

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.

 

[wuzak]

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.

I would think that the Buzzard could match that performance with not much work.

That said, the Hispano was given as an option for a number of British projects in the 1930s.

 

[Shortround6]

The Hispano was a good engine in 1932-36. In 1934 it was offering 860hp at 4000 meters. The Problem was that it was built light (470kg/1034lbs for the 1934 860hp version) and had no real reserve of strength to either increase RPM or boost pressure.
It doesn't take a rocket scientist to figure out that a 36 liter engine that weighs 32kg more than a 21.2 liter Kestrel might be lacking a little in either strength or durability.
By 1938 it was falling behind and minor tweaks (like the -51) were not enough to keep it competitive. The Z series might have done it but they don't show up as flying prototypes until the Spring of 1940 which is too late.

 

[Shortround6]

duplicate

 

[The Basket]

The Dewoitine D520 was certainly as good as a Hurricane with the 12Y and so were the Yaks.

I agree that the 12Y was not as good as the Merlin and certainly nowhere near as expandable but at a pinch with a no viable alternative...it would have been ok.

 

[Shortround6]

The Dewoitine D520 was certainly as good as a Hurricane with the 12Y and so were the Yaks.

Yaks didn't use the 12Y, they used the M-105 engine derived from the 12Y but had 3 valve heads instead of 2 valve heads, the above 2 speed supercharger drive with a low altitude gear ( both engines used a 10:1 drive for altitude but the Russians added a 7.8:1 gear that takes less power to drive and heats the intake air less for Low altitude (2000-2500meters and less). The M-105 alos gained about 100kg of weight between the new heads, the supercharger drive, the stronger crankshaft and the stronger crankcase.

I agree that the 12Y was not as good as the Merlin and certainly nowhere near as expandable but at a pinch with a no viable alternative...it would have been ok.

Unless you license the -51 version (which is too late) or spend a couple of years redesigning the 12Y it actually doesn't offer a whole lot more than the Peregrine would offer if you changed supercharger gears on the Peregrine.

 

[fastmongrel]

Would it have been case that if the Merlin was a failure then the Peregrine would also have been a failure as they were pretty much the same design.

 

[The Basket]

M-103 as well.

Just saying that for a mid 30s engine the 12Y would have been adequate and the prototypes of the Hurricane and Sptifre could have been flying.

Not saying the 12 was as good as a merlin and as an Englishman I never would! But Klimov got the ball game with it so overall it was ok although not auper.

 

[Shortround6]

Would it have been case that if the Merlin was a failure then the Peregrine would also have been a failure as they were pretty much the same design.

Well, the Buzzard was a scaled up Kestrel and the Peregrine was a "Merlinized" Kestrel, whatever that means. R-R built 4750 Kestrels which isn't bad for a Between the wars engine so we can assume that the Kestrel was fairly well sorted out. Peregrine used the same bore and stroke, same layout (V-12 with 4 valves/cylinder with overhead cams,etc) but was about 140lbs heavier and turned more rpm. Chances of the Peregrine having a fatal flaw seem pretty slim.