Westland Whirlwind revisited

GregP said:

So, Wayne, what do you think of the FMA Namcu a couple of pages back?

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Looks quite neat, very much like the Hornet.

Of course it was too late to be built in large numbers - jet fighters saw to that.

Just noticed that the Hornet had the same wing span as the Whirlwind - but had about 45% more wing area.

I recommend Niall Coruroy's book on the Whirlwind Whirlwind: Westland's Enigmatic Fighter: Niall Corduroy: 9781781550373: Amazon.com: Books , particularly the first four chapters on its development. It confirms what Edgar is saying about the Whirlwind and Peregrine's development. There were also other design problems, apart from those already mentioned:

The marginal capacity of the cooling system to cater for the Peregrine as it already existed - an uprated Peregrine would have required a redesigned cooling system. To redesign the system would have meant more testing and (possibly) custom made radiators/ oil coolers (NB: the book doesn't say this, but it's difficult to know what other aircraft could use radiators made for the Whirlwind)

The propeller shaft of the Peregrine was smaller than that of the Merlin, requiring custom made propellers.

Essentially, had the Whirwind been better designed and developed prewar, and had the Peregrine been more developed before the war started, and been used for more than one aircraft type, the Whirlwind might have had a chance. But in wartime it was simply uneconomic and impractical to continue developing an airframe/engine combination that would probably have been obsolescent almost before it became a practical production aircraft.

Good call about similar spans, Wayne! It definitely COULD be done since de Havilland DID it later.

The Whirlwind apparently had it's own share of issues, but nothing that couldn't have been corrected ... except maybe in a wartime economy with an imminent threat of invasion ... which is what it faced. Personally I like the whirlwind concept with the centerline cannons. Some great planes never made the cut. Not saying the Whirlwind was one of them, but it seriously might have had a chance if not for hanging it's proverbial hat on Peregrine. The same company made both the Peregrine and the Merlin ... go figure. One was a bust and the other a legend.

Reminds me of a pair of U.S.A. twins that never made it, the Grumman XF5F Skyrocket and the Grumman XP-50. Similar concept except with radial engines. At least they led to the Tigercat that DID get built, even if only in small numbers.

I bet the Westlands fans out there wish there were a few Whirlwinds around the warbird circuit today. I know I do, but engine parts would be the critical item! They only made 301 Peregrines and that's not enough for a flying plane today. They made 149,659 Merlins and parts are getting scarce!

If the Peregrine had been developed in line with Merlins development you could have had a 1100hp engine with good altitude performance. Had the Gloster F9/37 ever got into production with Peregrines and chin radiators it might have been enough to keep the Peregrine going.

F9/37 protoype with Peregrines

Handsome looking aircraft.

The F.9/37 with Peregrines was some 30 mph slower than the Whirly, though. With a 50% greater wing area, it would be a better airframe for the Merlins than the Whirlwind. The more voluminous fuselage (it was envisioned as a turret fighter at 1st) means easier addition of second crew member for night fighting duties.

Edgar Brooks said:

There isn't any;

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There is some that has survived


Edit: now that I think about it, what other ww2 aircraft had t-tails and made it into service? I can only think of the whirlwind, but this might just mean that I need coffee.

fastmongrel said:

Had the Gloster F9/37 ever got into production with Peregrines and chin radiators it might have been enough to keep the Peregrine going.

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I'm going to say it wouldn't.

If we suppose that Rolls-Royce could concentrate on two major engine projects, that is, the Merlin and another, I don't think the Peregrine would win out.

The competition is the Vulture and the Griffon. The Vulture had proved troublesome, but could be fixed - with a lot of resources.

The Peregrine could become a useful engine too, if given development time.

The Griffon was requested by the FAA. And very early on in the project it was suggested that it could be fitted to a Spitfire. A Peregrine could too, but what would be the point? The Vulture couldn't fit in the Spitfire airframe either.

So game over, the Griffon wins.

The order for just 200 Whirlwinds, later cut to 112 examples, meant that a mass production of Peregrines was out of question. No mass production means greater price per engine, ie. the economies of scale are not taken advantage of, so RR has a point here. A major point in any war.
An initial order in excess of 500 fighters would make it economically much more viable to establish a production line for the Peregrines, meaning 1000+ engines plus spares (25-30% of complete engines worth?) are needed.

tomo pauk said:

An initial order in excess of 500 fighters would make it economically much more viable to establish a production line for the Peregrines, meaning 1000+ engines plus spares (25-30% of complete engines worth?) are needed.

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Once again you have it back-to-front; R-R made no mention of economics, they just said that continuing with the Peregrine would cost Merlins at a rate of 2:1. An order for 1000+ Peregrines = 2000+ fewer Merlins, which was never going to appeal to the Air Ministry.

Then will you please enlighten us about why one Peregrine produced will cost two Merlins being not produced?

Sorry, but you'll need to ask Rolls-Royce; they made the statement, not me, the Air Ministry's paperwork doesn't go into details, and I'm certainly not going to speculate.


If you Google "George" Bulman, you'll find what he did during the war, and "W.R.F" is/was Wilfrid Freeman, of the U.K. government.

It may depend on the tooling in the factory making both engines and the relative production.
It isn't going to take much difference in time to machine a Peregrine crankshaft compared to a Merlin Crankshaft. However the crankshafts did NOT go from a forging (or forged blank/billet) to a finished crankshaft in a smooth succession of operations all performed on a very few machines. Only few procedures/operations would be performed on a particular part like the crankshaft and then they would be inspected and then on to the next step or several steps on the same/different machinery (lathes, grinders etc) using in some cases different jigs/fixtures and then more inspections and so on. In some cases the very early machining steps are to establish locating points for the next set of fixtures to hold the part with.
The time spent making Peregrine parts is going to be very close to the time spent making Merlin parts, however the time spent switching the tooling/fixtures back and forth between the two engines is dead time when no parts are being made.

If the "dead" time is charged to the Peregrine then limited production of Peregrine could very easily "cost" the loss of production of two Merlins.

Large scale production doesn't change the time needed to "machine" the parts but it sure cuts down on change overs of jigs and fixtures (dead time).

I worked at P W in the early 70s for a few years machining jet engine disks, Somedays my machine was working on compressor disks and some days it was turbine disks. Sometimes we finished a batch of parts in the middle of the day and and spent time swapping out the jigs/fixtures for the next "job" (batch of parts), At times the cutters were changed to ones of a specific radius to get the desired finished radius on inside corners. Production was low and there were spare machines which could sometimes be set up by special 'set up' men while the machine operators made the parts on the next machine in the line.

In WWII in 1940 any dead time spent swapping jigs and fixtures back and forth would not be looked at favorably.

Even Merlin production tended to be segregated. While Derby built the greatest variety of Merlins the shadow factories tended to specialize, Not an ironclad rule but Ford tended to build single stage two speed engines only. Glasgow built mostly single stage two speed engines although there were some two stage engines. Some low production number engines were only built in one factory.

In the US "shadow" factories also tended to build one type of engine, Ford only built single stage R-2800s. Nash-Kelvinator only built two stage engines.

Rolls-Royce might have been able to (been persuaded to) sell/give the Kestrel/Peregrine "tooling" (jigs, fixtures, inspection tools, etc) to another company but the lathes, milling machines, grinders etc were needed for Merlin production.


This loss of production is a very complicated question and having only a single, short sentence to go by leaves many questions unanswered. It is like reading a single sentence summery of a 10 page report.

I would note that P W was dropping the R-1535 at about the same time as being too small to warrant further development, Around 600 Miles Master IIIs were built using R-1535s in 1940/41.

I like the Whirlwind. I think it got a bit of a bad deal considering some of the other stuff the British continued to make at the time and with the benefit of 20/20 hindsight we can see that the "Hawker fighter" it was thrown over for arrived late, was more trouble prone than the Whirlwind and suffered from some of the same performance handicaps.
However the Peregrine had limited development potential due to it's size (even if it could match a Merlin liter for liter it was going to give 75-78% of the power of the Merlin) so it was always going to be a special application engine. It was the right decision to stop it.
It is just that some of the reasons given for stopping the Peregrine and Whirlwind seem to be after the fact.

Altogether a pretty good summation, Shortround.

I like the Whirlwind, too, mostly due to the fuselage cannon armament. If they had fitted a pair of 800 - 1100 HP radials, they might have had a very good attack plane for direct support of ground troops. But that also was not really needed in the 1940 - 1941 timeframe.

As you said, it was very probably the right decision made at the right time. Sometimes the right dcision is not always the easy decision.

I'm not sure that the ground attack plane was not needed in 1940-41 time frame, for either country in the war it those years.

tomo pauk said:

Handsome looking aircraft.

The F.9/37 with Peregrines was some 30 mph slower than the Whirly, though. With a 50% greater wing area, it would be a better airframe for the Merlins than the Whirlwind. The more voluminous fuselage (it was envisioned as a turret fighter at 1st) means easier addition of second crew member for night fighting duties.

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I am surprised the F9/37 was as fast as it was with 2 x Taurus it had a very thick looking wing and very bluff nose. They must have been very good examples of the engine.

Needed and wanted are two different things. And different officers/officials wanted different things. Some officers/officials wanted nothing to do with ground attack/army support planes as they though that such planes would take away from the "bomber campaign". Some officers/officials disagreed with them and some others may have flipped-flopped. Not wanting ground attack/army support planes in 1938/39 but wanting them in 1940 when the threat of German troops on British beaches was thought to be high and then back to not wanting them ( or thinking that the job could be done by any old obsolete aircraft that were handy).

The Whirlwind got their big reprieve with the fitting of bomb racks in 1942 ( around a year after a squadron commander first suggested it) because of a shortage of bomb capable Hurricanes in Britain. At the time Hurricanes were being sent overseas (North Africa and Far East) leaving only TWO squadrons of Hurri-bombers in England and without replacements one of them might have to be stood down. The conversion of the two Whirlwind squadrons doubled the number of fighter bomber squadron at the time. These fighter bombers were being used as replacements for Blenheims in the "forward lean" policy. Germans were NOT coming up to fight 3-4 squadron strength sweeps of Spitfires so some sort of bomb carrying aircraft had to thrown into the mix. 2-6 bomb carrying aircraft were often escorted by 2-4 squadrons of Spitfires in an attempt to force the Germans to fight. Whirlwinds had a rather better chance of "escaping" after bombing than Blenheims

The Whirlwind vs Spitfire comparison isn't quite right either. I have no doubt it was made at the time but the comparison should have been between the Whirlwind and the Hawker fighter (Tornaphoon/Typhado ?). They certainly planned a four cannon Spitfire in 1940 and built some four cannon MK Vs in the Spring/summer of 1941 but the numbers were few and apparently they were not well liked. The Spitfire does not become a standard four cannon fighter until the end of the war with MK XXI and the 2nd generation (2 stage) Griffon engine. The Tornaphoon/Typhado being a much closer match in capability, weight and resources needed. The Hurricane could carry the guns but it no longer had the performance needed even with a engine one generation better than than the engines in the Whirlwind.

The men at the time were trying to make the best decisions they could with the information they had at the time. Unfortunately they were getting some of their information from some rather overconfident salesmen and at times were comparing planes trying to enter squadron service with planes that would not be available for a year or more.

The Bristol Taurus deserves a book about itself, even if just because it is such a controversial machine. The F.9/37 was using the 'Bristol Taurus T-S(a) of 1000 HP', per Wikipedia, but:
1st - we don't know anything else about the T-S(a). Is the quoted 1000 HP figure for take off, or it is international power, or maybe it is max power at what altitude? The nomenclature might be for a prototype engine. Then it was re-engined with 'Taurus T-S(a)-IIIs' of 900 HP, performance fell by how much? Again - 900 HP on what setting, what altitude?
Lumsden mentions the Taurus III with 930 HP for take off, and 1060 HP at 14500 ft - a respectable performance for 1939-40. The Albacore and Beaufort would be using 'bomber versions' of the Taurus (II, IV, XII) that were providing more power at lower altitudes, 1060-1090 HP for take off and 1110-1140 HP at 4000 or 3500 ft. No aircraft used the Mk.III?

The Douglas DB7 was pretty fast with 1000 HP (at altitude) Twin Wasps, the F.9/37 was at least smaller than those.

fastmongrel said:

I am surprised the F9/37 was as fast as it was with 2 x Taurus it had a very thick looking wing and very bluff nose. They must have been very good examples of the engine.

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They were prototype engines that had as the closest service equivalent the MK III that offered 1060hp at 14,500ft.
Unfortunately being single speed supercharged engines the high gear ratio used cut take-off power by around 125 hp despite running 200rpm faster than any other service Taurus engine.

Actual performance of the engines in the F9/37 seems to be scarce.

Shortround6 said:

The men at the time were trying to make the best decisions they could with the information they had at the time. Unfortunately they were getting some of their information from some rather overconfident salesmen and at times were comparing planes trying to enter squadron service with planes that would not be available for a year or more.

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well said!

blueskies said:

There is some that has survived

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That is the approach which I mentioned earlier, made to Fighter Command (the letter was addressed to Sholto-Douglas) in which Westland claimed they could fit a Merlin to the Whirlwind. 'Certain undercarriage retraction problems' glosses over the serious nature of the design work required and as far as I know it wasn't completed.
This is a 'back channel' communication. Sholto-Douglas and Fighter Command did not control what aircraft were produced in British factories. The letter represents an effort to get Sholto-Douglas on side in an effort to save the Whirlwind for Westland.
In January 1941 the Air Ministry axe had already fallen (twice actually, including a limited reprieve) on the Whirlwind. It was a dead duck for reasons that both I and several others have already mentioned.
Cheers
Steve