Westland P.9 Whirlwind (1 Viewer)

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It had been seen by some in the Air Ministry as the standard fighter, Spitfire orders being for filling in until Whirlwinds were in quantity production. The Hurricane being maintained as it had extensive production capacity hence the willingness to export them and licence foreign production.
As a standard fighter it was seen as a 4x20mm cannon bomber interceptor. Had it been seen as a long distance escort fighter it could have been designed with increased fuel capacity. At that time it would have been designed to escort bomber from bases in France so the basic design would have been able to escort and fight as far as Berlin.
 
Yesterday, I had a look in the government files, in our National Archives, and found the following. There was never a plan to fit Merlins to a Mk.II, because they simply would not fit; the Whirlwind was designed around the Peregrine to be as small as possible. There was even talk of trying to find an American engine that would fit.
The biggest problem was the Peregrine; the original specification called for a maximum ceiling of (at least) 30,000', but the Whirlwind could barely reach 25,000', where its fighting qualities tailed off dramatically. The engine needed to be able to use 100 octane, but had only been designed for 87, so would need a lot of further development, and Rolls-Royce simply didn't have the capacity.
The work could not be diverted to Crewe or Glasgow, since they were 100% Merlin; Derby was having to build the Vulture, and working up on the Griffon, while helping with production of the Merlin X XX, so any work on the Peregrine would see 2 Merlins lost for each Peregrine, and the probable postponement of the Griffon as well.
When asked by Beaverbrook, on July 1st., Dowding had to point out that he still had only three, and they were giving continuous trouble, so he'd had to keep them well away from the area of heaviest fighting. He also was not happy with the high landing speed of 110m.p.h., which meant that it could never be used at night, since pilots had said, even at that speed, the controls were "sloppy."
He also said that he thought it was "an extravagant design," needing two engines to lift 4 cannon, when the forthcoming Tornado/Typhoon would do it on a single engine, and he'd always been unimpressed by Westland's workmanship on the Lysander. He did envisage that it would be ideal for ground attack, since its cannon were perfect for anti-tank work.
On October 27th., he told Beaverbrook that Westland were only committing to 114 Whirlwinds, after which they were switching to 50 Mk.I Spitfires, followed by the Mk.III (turned into the Mk.V, and Seafires, of course.)
On February 3rd. the Joint Development Production Committee decided that there were only two courses of action, which were to increase production, to cope with anticipated wastage, or close it down, so that decision was taken, as being the only practicable solution.
Talk of an escort fighter is a little odd, since the Air Ministry never saw the Whirlwind as such, nor did they ever see the need for one; losses of unescorted Blenheims and Wellingtons, in 1939 early 1940, had already pushed them towards night bombing.
Edgar
 
You would have to say that with no specialist role for the type, a problematic engine, a design difficult to stretch, and what appears to be high production costs (2 engines to one in the 'main" types) that cancellation was entirely justified.

As a two engine type, the whirlwind was not comparable to either the beau or the Mossie. Both these types were built for different purposes, and incorporated range and size to allow them to complete quite a range of different mission types. Daytime Escort LR fighter was not one of them, so the RAF continued to battle on wthout an adequate indigenous fighter to fit this spec. A great pity really
 
While I don't doubt that that is all in the archives some of it rings a little hollow. The development needed to go from 87 octane to 100 octane should be minimal. The Merlin required a number of hours of testing before it was approved but actually needed no new parts (maybe a new spring in the pressure regulator?) Both Bristol Mercury and Pegasus engines could operate on on 100 octane fuel. Granted you don't get the full benefit without some redesign but the Merlin went from 1030hp to 1310hp with just an adjustment of the pressure regulator. perhaps there was something about the Peregrine that would break trying to put out 30% more power but some increase should have been possible without much work. Granted the switch to 100 octane does nothing for altitude performance. I can't fault the men in charge for making decisions based on the evidence they had but history shows that some of their choices turned out not so well. The Tornado/Typhoon turned out to have very little capability that a MK II Whirlwind ( with Peregrines) wouldn't have had and 110mph landing speeds while not normal were certainly in use (P-47s). later Whirlwind pilots claimed no problem flying at night but with only 3 planes to go on the experience wasn't there.

The Spitfire was close to cancellation at times in 1938-39 for many of the same reasons ( slow production, bad workmanship, millions invested with no airplanes to show), fortunately the right decision was made in that case.

From a financial stand point I can understand RR wanting to get rid of the Peregrine, it was too small to ever be more than a niche engine. Bristol may have never made any money on the Taurus compared to the investment they put in.
 
You would have to say that with no specialist role for the type, a problematic engine, a design difficult to stretch, and what appears to be high production costs (2 engines to one in the 'main" types) that cancellation was entirely justified.

As a two engine type, the whirlwind was not comparable to either the beau or the Mossie. Both these types were built for different purposes, and incorporated range and size to allow them to complete quite a range of different mission types. Daytime Escort LR fighter was not one of them, so the RAF continued to battle on wthout an adequate indigenous fighter to fit this spec. A great pity really

The obvious competitor, which was never built, was the Supermarin Type 324/327. The Type 324 was proposed to specification F.18/37 for the Spitfire replacement, which was won by the Hawker Tornado and Typhoon. The specification was later extended to include cannon instead of the previously nominated 12 x 0.303" mgs. Supermarine refined the Type 324 as the Type 327.

The Type 324 and Type 327 were rejected by the Air Ministry, in part, because of the amount of time Supermarine took building the prototype Spitfire and getting it into production.

Supermarine also suggested that the 327 could serve as a backup for the Whirlwind, as the Whirlwind was running late by that time too.
 
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While I don't doubt that that is all in the archives some of it rings a little hollow. The development needed to go from 87 octane to 100 octane should be minimal. The Merlin required a number of hours of testing before it was approved but actually needed no new parts (maybe a new spring in the pressure regulator?) Both Bristol Mercury and Pegasus engines could operate on on 100 octane fuel. Granted you don't get the full benefit without some redesign but the Merlin went from 1030hp to 1310hp with just an adjustment of the pressure regulator. perhaps there was something about the Peregrine that would break trying to put out 30% more power but some increase should have been possible without much work. Granted the switch to 100 octane does nothing for altitude performance. I can't fault the men in charge for making decisions based on the evidence they had but history shows that some of their choices turned out not so well. The Tornado/Typhoon turned out to have very little capability that a MK II Whirlwind ( with Peregrines) wouldn't have had and 110mph landing speeds while not normal were certainly in use (P-47s). later Whirlwind pilots claimed no problem flying at night but with only 3 planes to go on the experience wasn't there.

The Spitfire was close to cancellation at times in 1938-39 for many of the same reasons ( slow production, bad workmanship, millions invested with no airplanes to show), fortunately the right decision was made in that case.

From a financial stand point I can understand RR wanting to get rid of the Peregrine, it was too small to ever be more than a niche engine. Bristol may have never made any money on the Taurus compared to the investment they put in.

You are correct. The Merlin only needed adjustment to the boost regulator to use 100 octane fuel, but it did need some testing to be sure.

The effect of the higher octane fuels tended to reduce the full throttle heights of an engine.

Let's not forget that at the time - around 1940 - Rolls-Royce were still busily trying to debug the Merlin (which they would not completely do until the two piece blocks came into production in 1942) and the Vulture.

I think that the war situation demanded that the Spitfire remained in production. Its replacement was some time away from production at the time of the BoB, and in the end was shown to be incapable of replacing the Spit.
 
You would have to say that with no specialist role for the type, a problematic engine, a design difficult to stretch, and what appears to be high production costs (2 engines to one in the 'main" types) that cancellation was entirely justified.

I have always wondered just how problematic the engine was, many engines show initial troubles, and the Peregrine, with just 301 (?) engines built continued in combat squadron service for about 3 years after production of the engine stopped. Granted for most of that time it was just two squadrons to use up that stock but if the engine had been the dog that the early Sabre was do you think they would have kept flying them? The Sabre and Typhoon program had the weight of thousands of each on order and no good alternative in sight in the short run.

Maybe the authors of articles/books about the Whirlwind picked their quotes but finding a Whirlwind pilot in print who didn't like the plane seems difficult.

I also wonder how the cost of two 12 cylinder Peregrines compare to the cost of one 24 cylinder Vulture or Sabre :)

The Vulture may be cheaper but I have my doubts about the Sabre.

A Peregrine is 78.5% the displacement of a Merlin. Even assuming that there is some problem that limits it's power to 70% of a Merlin a Peregrine "modified" to 70% of a Merlin 24 would have 1125hp for take off, About the same at 2250 ft, 1050Hp at 9250ft and 784hp at 18,500ft. Still no great shakes at 20,000ft and up but the Typhoon wasn't so hot up their either. With 2200hp to get the plane off the ground instead of the 1540hp of the MK I Whirlwind I imagine hauling a heavier war load wouldn't have been a problem. this if course is with 20/20 hindsight that knows that some of the alternatives didn't work out as promised.

Or for work at 20,000 to 25,000ft give it Peregrine versions of the Merlin 46. 990hp at 14,000ft instead of the MK Is 880hp at 15,000ft. same take off power though.

No inter-coolers, no two stage superchargers, no sleeve valves, no trying to stuff in Merlins. Just guns with 120rpm belt feeds (already trialed in two different installations) and more fuel in the fuselage.

Still not going to be an escort fighter but They kept building Hurricanes until 1944 for ground attack and that plane didn't have the longest legs in the world either :)
 
You are correct. The Merlin only needed adjustment to the boost regulator to use 100 octane fuel, but it did need some testing to be sure.

The effect of the higher octane fuels tended to reduce the full throttle heights of an engine.

It appears that way but the engines made just as much power as they ever did at the altitudes at and above the old full throttle height. Full throttle height being just what it says, the height at which the throttle can be fully opened with damaging the engine. The higher octane fuel allowed the throttle to be fully opened at a lower altitude without risk of detonation and so made more power at lower altitudes. The Merlin III's supercharger could supply 16lb of boost at 5500ft, 12lbs at 9000ft and 6lbs at 16,250ft. Changing fuel did nothing to affect the air supply. It just allowed the engine to use the extra air available at the lower altitudes.
 
Merlin 24 is a two speed engine. Peregrines had teh single speed supercharger.

Merlin 32 was rated, according to Rolls-Royce Merlin - Wikipedia, the free encyclopedia, at 1645hp at 2500ft. An equivalent Pergrine could have been used for a Whirlwind LF.II. If we use the 70% theory that would be 1152hp at 2500ft.

If we use BMEP for comparison, your Merlin 46 comparison goes from 990hp @ 14,000ft to 1112hp @ 14,000ft @ 3000rpm. If we have to restricte the rpm, as was done for the Vulture, to say 2850rpm then we are back to 1056hp.
 
It appears that way but the engines made just as much power as they ever did at the altitudes at and above the old full throttle height. Full throttle height being just what it says, the height at which the throttle can be fully opened with damaging the engine. The higher octane fuel allowed the throttle to be fully opened at a lower altitude without risk of detonation and so made more power at lower altitudes. The Merlin III's supercharger could supply 16lb of boost at 5500ft, 12lbs at 9000ft and 6lbs at 16,250ft. Changing fuel did nothing to affect the air supply. It just allowed the engine to use the extra air available at the lower altitudes.

True enough. All performance improvements of the engine with higher octane fuel are below the full throttle height with the lower fuel grade, gradually reducing to be the same at that full throttle height.
 
Merlin 24 is a two speed engine. Peregrines had teh single speed supercharger.

Merlin 32 was rated, according to Rolls-Royce Merlin - Wikipedia, the free encyclopedia, at 1645hp at 2500ft. An equivalent Pergrine could have been used for a Whirlwind LF.II. If we use the 70% theory that would be 1152hp at 2500ft.

If we use BMEP for comparison, your Merlin 46 comparison goes from 990hp @ 14,000ft to 1112hp @ 14,000ft @ 3000rpm. If we have to restricte the rpm, as was done for the Vulture, to say 2850rpm then we are back to 1056hp.

The Merlin X with a two speed supercharger was shown at the 1938 Paris air show, The two speed Merlin XX was in production (limited quantities ?) in July of 1940. The XX Merlin was the first with Hooker modified supercharger. A two speed drive to the supercharger was about 30-40lbs on a Merlin and Bristol and Armstrong Siddely were already using them. A-S being the first company anywhere to put the two speed supercharger into production. Allison not withstanding, it doesn't seem like that big a trick to use a two speed supercharger.

I wanted to be conservative in my estimate to show that, unknown problems aside, The Peregrine could make enough power to compete against some of the big 24 cylinder engines. Single seat fighter, one Vulture or two Peregrines? cost and weight? Yes the Vulture will come out ahead but the Peregrine wasn't a 2 Peregrine=one Merlin situation given any development of the Peregrine at all.
 
I feel that, if Rolls-Royce said that the work couldn't be done, without some disruption (including delays to the Griffon,) and a great deal of time, you should do them the courtesy of believing them, after all, no company is going to turn away work, unless it has to.
Remember that the Germans were sending the 109F over the U.K., before the end of 1940, and reports anticipated that it could reach 38,000', which even the Spitfire struggled to reach, and neither the Hurricane, nor the Whirlwind, had a hope of getting there. The Merlin 45 was on its way (first flew in a Spitfire V in April,) which the RAF would need desperately.
There was always the expectation of a second Battle of Britain, in early 1941, and the Spitfire V was the only likely opponent for the new 109s. We were also still the only nation/commonwealth fighting the Germans at that time, with Russia viewed with deep suspicion, as an ally of Germany. Dowding had always said that he rated the Whirlwind as ideal for ground attack (as it proved,) so the lack of a decent maximum operational height would have been immaterial, and it would have been vital in the event of the (also anticipated) delayed invasion.
Added to all of the problems, Westland had forecast that they would only produce one Whirlwind, per week, while they, Supermarine, and Castle Bromwich could be turning out far more Spitfires in the same time.
Just to help make up the minds of the hierarchy, Supermarine had managed to fit the longer Merlin 45 into the same engine space as the Merlin III (something they hadn't been able to do with the XX, which, as with the Hurricane, made the Spitfire III fuselage 4" longer.)
Edgar
 
I feel that, if Rolls-Royce said that the work couldn't be done, without some disruption (including delays to the Griffon,) and a great deal of time, you should do them the courtesy of believing them, after all, no company is going to turn away work, unless it has to.

Companies will turn away work if they feel it is unprofitable or is a dead end. P&W actually returned money already paid in order to get out of contracts for liquid cooled sleeve valve engines so they could concentrate on the R-4360.

With a bit of cynicism I believe that is what R-R did with the Peregrine. Even in 1940 they knew that the 'market' for 900-1100hp engines was not only going to be limited but declining just as P&W knew the market for the R-1535 Twin Wasp Junior (just 15 cu in smaller than a Taurus) was a dead end. You are right, R-R did not have the resources to develop 4 different engines. So from a marketing perspective they had the 900-1100hp Peregrine, the 1100-1500hp Merlin, the 1750-22250hp Vulture and last (in development) the 1500-1900hp Griffon. With Napier touting their 2000hp Sabre and Bristol already competing head to head with Merlin with the Hercules and getting a type rating for the 2000hp Centaurus spending even a shilling on developing the Peregrine was money wasted. Now is R-R going to admit that that ditching the Peregrine was a commercial decision? Especially if the Vulture turned out not to be rousing success? Luckily the Merlin proved more capable of stretch that most anybody could have dreamed of and the Griffon was allowed to come to maturity.

Remember that the Germans were sending the 109F over the U.K., before the end of 1940, and reports anticipated that it could reach 38,000', which even the Spitfire struggled to reach, and neither the Hurricane, nor the Whirlwind, had a hope of getting there. The Merlin 45 was on its way (first flew in a Spitfire V in April,) which the RAF would need desperately.

A bit of failed intelligence there. While the 109F would be able to reach 38-39,000ft with the 601E it would not be for almost a year. Granted the Germans had development problems of their own which caused the delay but reaching 38,000 ft and fighting there are not quite the same thing.

For example the service ceilings (climb 100ft/min) of the 109E (yes "E"), Hurricane I, Hurricane II and Spitfire I were 35,200ft---35,000ft ---37,600ft and 37,400ft. The operational ceiling (climb 500ft/min) for the four planes was 31,900ft---31,400ft---34,900ft and 34,000ft. Rate of climb at 30,000ft for the 4 planes was 740fpm---660fpm---1160fpm and 1020fpm. It does make one wonder what the Spitfire MK III with a the Merlin XX would have done. The Thinking at the time may have been that the Spitfire with the MK X11 or coming Merlin 45 would be good enough while a Hurricane WITHOUT a XX was hopeless and the game was still total number of aircraft.

Just to help make up the minds of the hierarchy, Supermarine had managed to fit the longer Merlin 45 into the same engine space as the Merlin III (something they hadn't been able to do with the XX, which, as with the Hurricane, made the Spitfire III fuselage 4" longer.)
Edgar

Color me confused on this one. You can't fit the longer (by 4in ?) Merlin MK XX into the Spitfire (inspite of doing it on the MK III) yet you can fit the longer (dimension not given) Merlin 45 without as much trouble? Merlin 45 is a Merlin XX without the 2 speed drive and a slightly lower drive ratio. 9.089:1 instead if 9.49:1. basically a Merlin XX with low gear left out although there may have been differences in the block that do not allow one to be changed to the other. All supercharger and carburetor parts were the same between the two engines.
 
The engines were not the same; the blower casing of the XX was a different design, completely. On the 45, the basic difference was that carburettor airflow was taken through an elbow, which directed it into the middle of the impeller; on the earlier Marks, the air/fuel mix was directed onto the edge of the fan blades This made the impeller more efficient, but the elbow lengthened the engine by a couple of inches (ish.) To work round this Rolls-Royce turned the carburettor controls through 180 degrees, thereby tucking them under the crankcase. This couldn't be done on the XX's blower casing, because the extension was at the front, just aft of the crankcase (note the larger gap between the carburettor and the crankcase.
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One other item of interest might be that there were nowhere near enough Merlin XX to satisfy the Hurricane II the Spitfire III, so the latter was ditched; after all, the Hurricane was going to be needed for ground attack against the expected invasion. With regard to the "failed intelligence," you can blame Dowding for that, though, in October, pilots had reported the 109 flying 2,000' above them, but showing a marked disinclination to come down and fight, and they weren't interested in going up after them, so the formations just sailed past each other.
Edgar
 
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We seem to have a conflict in sources. In "The Merlin in Perspective-the combat years" by Alec Harvey-Bailey, No 2 in the Rolls-Royce Heritage trust series it states both in the text and in tables that the Merlin XX used the single central entry supercharger. In other books it says that the Merlin XX was the first Merlin to use that type supercharger or that the Merlin XX was the first to benefit from Hooker's work. Perhaps the two speed drive required the supercharger to be spaced away from the engine a few inches?

I know that there not enough MK XX engines to go around. As I said, the Spitfire could get by without it and still be a creditable fighter in 1941, the Hurricane could not, and there weren't going to be enough Spitfires if you stopped production of the Hurricane. Heaven forbid that bomber command give up some of their allotment of MK XX engines though :)

If the Hurricane was truly to be a ground attack machine in 1941 the problem could have been easily solved by giving the Merlin XXs to the Spitfires and using a single speed supercharger in ground attack Hurricane with super charger ratio picked for low altitude performance or the cropped impeller MK 30 used in the Fulmar MK II. 1300hp for take-off and 1360hp at 6000ft in Jan 1941.
 
The trouble with the XX, for the Spitfire III, was that it lengthened the nose by 4", which meant that all of the cowling parts had to be redrawn, and reshaped, and the u/c had to be raked forward 2", to stop any tendency to nose over. Raking the u/c forward meant that the wheel sat at a different angle in the well, so the pintle had to be changed, to make the leg hang lower, and that meant that the wheel cover had to be reshaped into a curved cross-section, rather than flat. Putting the XX into the Hurricane proved to be a lot less hassle, and the 45 into the Spitfire V even less. I have (years ago) crawled under a Mk.I Mk.V Spitfire, and can confirm that the V's carburettor intake is a couple of inches further back. Having been a modeller, for nearly 60 years, and having to contend with "experts" on the Spitfire, who've never been near one with a tape measure, means that a tape is permanently sitting in my camera bag. Incidentally, I'm not presumptuous enough to include you in that "expert" jibe.
Strangely enough, in the paperwork, regarding the Merlin production, it says that, to get the required number of XXs, some would have to taken from the bomber allocation, but that wouldn't matter, since airframe production always lagged behind the engines, anyway.
Our sources of information are not in conflict, in fact they're identical, since I got the Merlin drawings from the R-R Heritage Trust, and the information about the 45's carburettor came from a talk, on the 40th anniversary of K5054's first flight, given by Sir Stanley Hooker. (I wasn't lucky enough to attend, but I managed to get hold of a pamphlet.)
If you open the RRHT's book at pages 76 78, and compare the photos, you'll see that the XX has an extra "compartment" between the crankcase and the compressor stage (housing the two-speed gearing, which the 45 didn't have, I presume.)
You do realise, I trust, that we're liable to get a rollicking, from "management," for turning a Whirlwind thread into one on the Spitfire?
Edgar
 
I can see both points. I am certainly not a "hands on expert" and I do thank you for the reminder that just because one airframe can be easily modified in a certain way does not mean another airframe can be.
The same with engines, just because Wright Cyclones could have have a 2 speed box added to an existing engine doesn't mean another engine could. Allison was famed for the ability to turn a basic block into a variety of versions. P&W on the other hand, had the licensees build one stage and two stage engines in separate factories. I don't know but would guess that there was something about the Merlin engine block that prevented one from turning a single speed engine into a two speed even if you had the parts, perhaps part (or all?) of the extras space needed for the two speeds was cast in one piece with block? This doesn't make it better or worse than a rival engine, just different.

We also tend to forget just how desperate they were for numbers of aircraft at times during WW II. The US certainly made it's share of bad decisions (in hind sight) of continuing production of certain models of aircraft or refusing to modify an aircraft because of an interruption in production.

what is strange (for many aircraft) is what is counted as a problem in one scheme or conversion seems to disappear or is easily accommodated just a few months later in a different scheme. Maybe my book is wrong but weren't the U/C legs raked forward on the MK V Spitfire (or at least some of them?) But what is counted as an unacceptable delay in certain conditions may not be that big a problem due to different circumstances just a few months later.

I do believe the Whirlwind was a missed opportunity but it seems that many of the "problems" with were temporary or just mistaken (or out of time) impressions. For instance in 1940 the landing speed of the Whirlwind was frighteningly high to officers who had flown biplanes in their flying years. It 1943 it would almost be common place or in the same league with B-26s, A -20s and P-47s. It was too small to be turned into the "wonder" plane some people claim but given the same development (or patience) a few other planes got it could have been a decent substitute for the Typhoon, except without the Typhoon there might have been no Fury :)
 
The Vc had the same 2" forward rake as the Mk.III, and this was continued on to the VII, VIII, IX XIV; I don't have the official reason, but suspect that it might have had something to do with having four 20mm barrels sticking out in front of the leading edge, which might have adversely affected ground handling.
It's easy to say,"Stick a big/bigger compressor at the back of the Peregrine, but if, like the Hurricane, the engine was already tight against the bulkhead, it would have to move forward, with all the implications for the CoG that entails.
Camm wanted to fit the Griffon into the Hurricane, and had all of the drawings ready, but it meant that the spars, in the centre-section, would have had to be raked forward, to bring the wings forward and the CoG with them. Camm was told to forget it, and concentrate on the Tornado/Typhoon.
Remember that the IX, with the 60-series engine, was the result of someone's brainwave; the 60s were planned for bomber production, until there was the spoken thought," What if we put it into the Spitfire?" The rest, as they say, is history.
Edgar
 
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