Did The Prop Doom The Westland Whirlwind?

[stona]

They were more concerned with fixing the problems with the aircraft supposedly already in service than with modifying the way the guns operated.

The actual serviceability rates are laughable. This wasn't just the well known and fatal problems with slats and wing tips, which caused the type to be grounded, but problems with failed welds in the carburetor intake ducts, exhausts, fuel breathers, tail wheel oleo, rear bulkhead and rudder hinge casing, failed hydraulic pipes, fuel tank sealant in the fuel filters, partial canopy collapse etc., etc.

When the Whirlwind was more or less forced into service in late 1940 it was far from the finished article.

Cheers

Steve

 

[Shortround6]

No argument on the early deployment but plenty of other aircraft had trouble in their early days.
Petter had tried to be just a little too tricky in some features, too.

 

[C.Warren]

The following link has a well done article on what the real problems were with the Westland Whirlwind.

The Aviation Historian - Issue 20 : Free Download & Streaming : Internet Archive

And this link has the 1938 technical paper referenced in the article.

https://ia802707.us.archive.org/29/...19930091714/NASA_NTRS_Archive_19930091714.pdf
Thank you for these links: "I found all this fascinating and quite informative.

"
A question I would like an answer for would be: why not design the Whirlwind for Merlins to start?, Was this to spread the risk of the Merlin engine not reaching a reliable point so the spec was for the earlier engine which RR thought could be tweeked?

 

[tomo pauk]

"
A question I would like an answer for would be: why not design the Whirlwind for Merlins to start?, Was this to spread the risk of the Merlin engine not reaching a reliable point so the spec was for the earlier engine which RR thought could be tweeked?

A million dollar question, the 1st one
Merlin was an eariler engine, not Peregrine.

 

[Shortround6]

I believe the "official" position was that a single engine plane could not carry the load of four cannon and so a twin was requested. Petter had a real "thing" for small aircraft so he tried to design the smallest twin that he could.
British engine design/procurement seems a bit muddled at this point (1936-38?) with several projects for 'middle' powered engines. Companies thought they needed to offer a range of engines to suit various needs. Unfortunately in this attempt to please everybody they exceeded their own engineering capacity and some projects bogged down/dragged out.

A lot of people get hung up on the dry weight of an engine. To the aircraft designer the weight of the power plant is what counts and the weight of the power plant (propeller, radiators, engine mounts, oil coolers, cowling, starter etc) can be 60-70% more than the dry weight of an engine.
for example the weight of an engine in an early Spitfire was 1412lbs yet the weight of the "powerplant" not including fuel tanks was 2120lbs and this is for a wooden 2 blade fixed pitch prop.

A twin Merlin power plane would have needed a bigger wing, bigger landing gear, bigger tires (They had to get special dispensation as it was for the Whirlwind so they didn't have to go to bigger tires and redesign the rear of the engine nacelles) more fuel and so on.

 

[stona]

There was no clear and explicit program during re-armament that allowed the aero engine industry to plan very effectively. Merlin requirements were revised SIX times in 1939 alone!

The fate of the Peregrine engine was really sealed as early as June 1939 when Hives wrote:

"If there was a war it would be obvious that the main production would be on the standardised and proved types of engines... Our proposal is that it should be a definite policy of the Air Ministry that the plant for producing the standard engine, in our case the Merlin, should not be broken down to produce another type."

A consequence of this policy (the memorandum is actually titled 'Policy') was that Rolls-Royce's development programme was cut back. The Peregrine (and the Exe) were abandoned during the early months of the war in order to concentrate as much technical effort as possible on the Merlin. With that, and the resultant production limit on the Peregrine, the fate of any aircraft designed to use it was also sealed.

While the PV.12/Merlin might strictly be regarded as an earlier engine than the Peregrine, the Peregrine was a development of the Kestrel (so named in 1930), dating back to the F series engines of the late 1920s.

The Whirlwind was a victim of its delays too. When cannon were installed on the Hurricane and more particularly the Spitfire, these developments of the high speed research programme also fulfilled the role of cannon fighter for which F.37/35 had been written.
The Whirlwind also conflicted with other requirements. In November 1937 Freeman queried the small difference in speed between the Whirlwind (F.37/35) and the requirement for a new fighter (F.18/37) which led to the Tornado/Typhoon. He thought that the speed of the twin should be 420 mph, which was a bit optimistic. Dowding made it clear that he was happy with the single engine Spitfire and Hurricane, he may have had concerns about production problems (which proved justified) or financial constraints on the eventual number produced. It was eventually decided that F.18/37 should proceed, but be abandoned if it showed little advantage over the Whirlwind. The failure of the Whirlwind ensured that the Tornado-Typhoon-Tempest line went into production.

Cheers

Steve

 

[Shortround6]

I would note that original estimates for the Beaufighter also claimed a 360mph top speed which also cast doubts on the need for the Whirlwind.

as it turned out both the Estimates for the Beaufighter and the Typhoon were very optimistic.

 

[JJWilson]

This has been a very interesting thread to read and learn from, I for one am still puzzled that Whirlwind didn't test out other engine platforms. The Peregrine wasn't fantastic, and the Merlin seemed problematic from what I've read to implement as well. Would Allison V-1710 engines be a better fir for the aircraft?

 

[stona]

The Whirlwind died with the Peregrine. It really is as simple as that. There was nothing much wrong with the Peregrine engine, had it remained in production and development it might have proved a very good engine indeed.

Even in 1942 there were issues with the Peregrine, however minor, they were serious. It developed problems with the three-way oil union, which grounded all Whirlwinds for several days, although Rolls-Royce rapidly delivered new, strengthened unions, and all aircraft were quickly serviceable again.

The Merlin Whirlwind is just wishful thinking and there was not much chance of a British aircraft being equipped with an American engine in 1936-1940.

Cheers

Steve

 

[b0ned0me]

Merlin seemed problematic from what I've read to implement as well. Would Allison V-1710 engines be a better fir for the aircraft?

Merlin and V-1710 - brother from another mother. If you can't fit one into the airframe you won't fit the other.

 

[Shortround6]

The Whirlwind was a pre-war design and first flew in Oct of 1938. The British were unlikely to buy engines from the US in large quantities (although they were ordering Harvards and Lockheed Hudsons and in any case the Allison in 1938 was pretty much an experimental engine. While the US had ordered a total of 43 engines from Allison in 1938 (many delivered in 1939) Allison delivered 12 V-1710 engines and one V-3420. 1939 deliveries would total 48 engines. 1940 saw about 1150 engines of which only 342 went to the Americans.
Just a few months could change a lot of things but the Whirlwind was already too far along for major engine changes.
Please remember that field length and even ground pressure of tires on turf figured into British pre war requirements.

 

[Shortround6]

The Whirlwind died with the Peregrine. It really is as simple as that. There was nothing much wrong with the Peregrine engine, had it remained in production and development it might have proved a very good engine indeed.

Even in 1942 there were issues with the Peregrine, however minor, they were serious. It developed problems with the three-way oil union, which grounded all Whirlwinds for several days, although Rolls-Royce rapidly delivered new, strengthened unions, and all aircraft were quickly serviceable again.

The Merlin Whirlwind is just wishful thinking and there was not much chance of a British aircraft being equipped with an American engine in 1936-1940.

Cheers

Steve

Pretty much agree, My own personal fantasy is that the Peregrine is farmed out to another manufacturer who also builds it as a tank engine replacing the Nuffield Liberty. Gives you some economy of scale of manufacture. Gets rid of the Liberty and even without a supercharger and running on 77 octane fuel would power any British tank short of the Centurion

 

[JJWilson]

Merlin and V-1710 - brother from another mother. If you can't fit one into the airframe you won't fit the other.

Absolutely, that I understand, I don't think I should have used fit, maybe worked is better . Putting aside the fact that the British were unlikely to buy Allison's en masse, and that the Whirlwind was already dead, wouldn't the Allison potentially be a good fit for the Whirlwind? Sure they had problems with the Merlin, but I find it hard to believe that both the Allison and Merlin engines both couldn't be utilized in the Whirlwind successfully.

 

[Shortround6]

Please look at the Whirlwind again, it is a small airplane

 

[JJWilson]

Please look at the Whirlwind again, it is a small airplane

I'm not trying to be difficult, but the Whirlwinds wingspan, 45ft is only 7 ft shorter than the P-38 52ft, I don't see how an Allison is to big for the airframe, when a Merlin isn't?

 

[Shortround6]

Nobody knows what the "proposed" Merlin Whirlwind would have looked like or what changes would have been made. It is all based on a few sentences in a single letter as far as I know.

as far as comparing the Whirlwind to the P-38 you have a 250sq ft wing and 327 sq ft wing and you have an 8300lb empty aircraft to an 11,780lb aircraft empty.

 

[stona]

If you want to indulge in 'what iffery' I would suggest the best chance for the Peregrine, and thus the Whirlwind, would be some sort of licensing deal whereby Packard could produce and develop the Peregrine in the U.S. There was NO chance of Rolls Royce doing it.
I've seen it suggested that they might develop a 1000 hp version (did RR get this out of a Peregrine?) which they could also use as a marine engine in US PT boats! I would credit the idea if I could remember where I read it. It's not something I would have thought of.

I believe the V 1710 was suggested, by Petter again, but had about as much chance as the Merlin. This must have been in 1940, but I can't find a reference. SR6 has already pointed out some fairly serious flaws in this idea, quite apart from British reluctance to fit a US engine to a British aircraft, not at all the same as importing a US aircraft with US engines. Even that was born out of desperation rather than desire.

Cheers

Steve

 

[Shortround6]

The Packard marine engine was a 2500 cu in engine (41 liters) derived from their old (1920s) aircraft engine. It had a lot more low end grunt and a lot more potential than any 21 liter engine. It eventually hit 1500hp installed in boats.

Sorry I just can't see a Fairmile D boat with four Peregrines

 

[tomo pauk]

If you want to indulge in 'what iffery' I would suggest the best chance for the Peregrine, and thus the Whirlwind, would be some sort of licensing deal whereby Packard could produce and develop the Peregrine in the U.S. There was NO chance of Rolls Royce doing it.
I've seen it suggested that they might develop a 1000 hp version (did RR get this out of a Peregrine?) which they could also use as a marine engine in US PT boats! I would credit the idea if I could remember where I read it. It's not something I would have thought of.

Developing and producing the Peregrine in the USA would've probably been a bad idea, and yes, I like the Whirlwind. Allies needed 1500-2000 HP V12s, not yet another 1000 HP type.
Peregrine was making 885 HP on 87 oct fuel at 15000 ft, boost being +6.75 psi. The 100 oct fuel allowed for +9 psi, result was probably around 1000 HP at 10000 ft?

 

[pbehn]

The British could certainly have used a long range heavy fighter before they actually got one, its just that the Whirlwind wasn't it.