Westland Whirlwind revisited

So if the consensus is that the Welkin is a completely different aircraft from the Whirlwind, I actually didn't get that from the images and the Wikis. But if that is the case, then perhaps we can answer the question of whether the Whirlwind could be reformed with 'not with merlins ', but then ask the question could a different aircraft which is a close derivation of the Whirlwind have been made, and the answer to that is probably yes I think.

Next question after that is, how much bigger do you need to make the Whirlwind before it can handle the larger and heavier engines, and maybe carry some more fuel. In terms of twin engined British fighters, there is plenty of room in size between the Whirlwind and the Beaufighter. You could easily fit a Whirlwind inside the volume of a Beaufighter and if you broke a second one into pieces I think you could fit that too. But the Mosquito isn't so much larger really, just eyeballing it, it appears to me to be about 20 or 25% larger. So a Whirlkin would need to be pretty close in size to the Whirlwind (but maybe with larger aspect ratio wings).

But I'm not sure new wings are going to take so long. The biggest delaying issue seems to usually be engines. Considering the speed in which they got the Miles M.20 from drawing board to flying around, I'm going to guess that this could have been done in time for a Whirlkin to still have a useful combat niche, assuming you were going to fit a merlin or some other well established engine. Whether it would have been worth it depends on the performance, range, handling etc. of the prototype. And whether you get lucky and no test pilot crashes one.

One other pertinent thing I couldn't suss out about the Welkin is that it seemed like it was thrown together quite early (1941?), but then they tinkered with the pressurization and compressibility issues with the weird wing etc. for years. Must have been weird to be working on a project like that as the war goes on by. But is that the right timeline?

I have never seen any book that gives the Welkin wing the size that Wiki does and doesn't come close to the weight.

There is an alternative airframe.

But be sure you get the right specs. The pictured plane has Peregrine engines and most published specs use the weights for the other prototype using Taurus radials. About 400lbs lighter tare and 500lbs lighter all up.
Don't believe the speed either. The experamantal Taurus engines went away and not production Taurus ever displayed the power at altitude that came close again.
This plane used a 50ft wingspan (or close enough) and 386 sq ft. of wing. Not much heavier than the Whirlwind but as tested in only had two 20mm guns. Other layouts had four .303s or even a total of six 20mm cannon (not tested.)

Speed with Peregrines was 330mph at 15,000ft (?)

You do have a bit more wing and fuselage to play with. Stick the Radiators in the wing root leading edge? Put them under the wing like Bf 110? somewhere else?

The Beaufighter was a skinny fuselage Beaufort torpedo bomber. Same wing and tail (at least in prototype form) so it was way over sized to be a "fighter" but it was could be completed early and it held a lot of fuel. And we are back to the British using some dubious drag figures. Bristol estimated a top speed of 360mph, just like Hawker estimated well over 400mph for the Typhoon.

That's another new plane for me.

Shortround6 said:

I have never seen any book that gives the Welkin wing the size that Wiki does and doesn't come close to the weight.

There is an alternative airframe.
View attachment 710610
But be sure you get the right specs. The pictured plane has Peregrine engines and most published specs use the weights for the other prototype using Taurus radials. About 400lbs lighter tare and 500lbs lighter all up.
Don't believe the speed either. The experamantal Taurus engines went away and not production Taurus ever displayed the power at altitude that came close again.
This plane used a 50ft wingspan (or close enough) and 386 sq ft. of wing. Not much heavier than the Whirlwind but as tested in only had two 20mm guns. Other layouts had four .303s or even a total of six 20mm cannon (not tested.)
View attachment 710611
Speed with Peregrines was 330mph at 15,000ft (?)

You do have a bit more wing and fuselage to play with. Stick the Radiators in the wing root leading edge? Put them under the wing like Bf 110? somewhere else?

The Beaufighter was a skinny fuselage Beaufort torpedo bomber. Same wing and tail (at least in prototype form) so it was way over sized to be a "fighter" but it was could be completed early and it held a lot of fuel. And we are back to the British using some dubious drag figures. Bristol estimated a top speed of 360mph, just like Hawker estimated well over 400mph for the Typhoon.

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I am a big fan of the Gloster F9 as many others are as well, and I agree that it could have fit into that slot. The only reason it was canceled is they wanted Gloster to focus on jets.

The F9 had a more conventional wing shape and probably had room both for fuel and bigger engines, I would guess.



That is definitely well beyond the scope of adapting a Whirlwind or Welkin.

However the F9 does fit pretty much the same niche (small twin engine fighter). And I think as a fighter it may have had even more potential than the Beaufighter, which did great as a heavy fighter / all around stuff wrecker. But wasn't really ideal for tangling with Bf 109s.

Could the F9 have taken merlins? Wiki doesn't say how much fuel it carried, do you know of a range estimate?

I want one.

Petter expressly stated that the Merlin could be fitted to the Whirlwind airframe. This was late in the day and followed finding solutions to installation clashes, but he was quite explicit. The Allison had also been offered earlier.

There is the following internet site on the Whirlwind that is worth reading. It includes some details of Petter's Merlin proposal and the changes that would have been needed to make it work, and explanations of more recent research blaming the props more than the engines for the lack of performance.


"Long pooh-poohed on internet forums as being unfeasible, the research of Niall Corduroy has found that such a scheme was indeed considered and design studies got to quite an advanced stage. There was too little clearance between the fuselage and the engines to use any of the standard Merlin propellers, so shorter, four-bladed ones would have to be used instead (similar to the ones used on the later deHavilland Hornet). The other problem would have been the location of the Merlin's updraught carburettor, which would have protruded into the space used by the undercarriage (the Peregrin had a downdraught carburettor that sat above the undercarriage enclosure). This would have meant the Merlins would have to be repositioned further forward with a corresponding redistribution of weight in the rest of the airframe ( the later Merlin 130 series, used on the deHavilland Hornet fighter, was redesigned to have a downdraught carburettor, but this did not become available until 1945). In any event, Westland seemed confident they could produce a Merlin-powered Whirlwind. In a letter to Sholto Douglas, in January 1941, they said their new design, with Merlin XX engines, would have a top speed of 410mph (660 kph), a ceiling of 37,000 feet (11278 metres), a range of 800 miles (1287 km) and carry an armament of four 20mm cannon with 120 rounds per gun and an additional two machine-guns. At the time, it was expected that the Luftwaffe would renew their attack in the Spring, and every Merlin XX engine was desperately needed to build Hurricane Mk IIs to re-equip the squadrons flying the earlier Hurricane Mk I, so this plan would have been a non-starter."

And this on other proposals.

"Petter presented two designs of brand-new twin-engined fighter to Air Ministry specification 6/39, issued in April 1939, to take the even more powerful Rolls-Royce Griffon engine. The first design had tractor propellers and a tailwheel and could be powered by Merlin engines if no Griffons were available. The second had pusher propellers and a nosewheel undercarriage and was a strictly Griffon-only design. This specification was one of those dropped when Beaverbrook took over as head of the Ministry of aircraft production in 1940 and ordered production concentrated on only a few types."

Niall Corduroy's book is available on Kindle
Amazon product ASIN B00K1NOR7S
View: https://www.amazon.co.uk/Whirlwind-Westlands-Enigmatic-Niall-Corduroy-ebook/dp/B00K1NOR7S/ref=sr_1_2?crid=7BN0G6KWZZIH&keywords=Westland+Whirlwind&qid=1678471959&s=books&sprefix=westland+whirlwind%2Cstripbooks%2C128&sr=1-2

Petter may have been desperate or still looking at things with rose tinted glasses?

You had cooling issues with the Whirlwind in the production version with the triple circular radiators. And original cooling flaps.

They want to fit rectangular radiators that will more fully use the space/air flow. This will allow up to a 26% (?) increase in cooling "power".
This will take care of Petters MK II with 1000hp Peregrines using 12lb boost and 5000ft more altitude. Maybe this existed at RR or maybe these were Petter's power estimates?
This is shot down and Petter comes back with the Merlin XX plan with the four bladed props. Granted in early 1941 when they come up with this plan the Merlin XX is using 9lbs of boost and not the later 12-14/16lb limits. However even an engine making 1150hp is making 30% more power than the Peregrine and there could be cooling problems even with a few minor tweaks.
There was more room for even bigger radiators.
1. take the carb intake out of duct (if it wasn't done already) and stick it on top (tried at least once?).
2. take the oil cooler out of the duct and stick it somewhere else? under the outer wing? bottom of the engine nacelle?
3. extend the wing one bay ?
4. Stick the whole radiator somewhere else?

You can fix an lot of things if you throw enough time and money at them.

The Merlin XX weighed about 300-310lbs each, more than the Peregrine, dry weight. It used the bigger prop hub on the propeller. 4 small blade or 3 broad cord blades (neither of which were in use in Britain at the time but were being worked on ?) adding more weight up front.

Maybe Petter had solutions in his mind for these problems or believed they could be worked out.
Spitfire "cheated" as they stuck bigger/heavier engines in the front 0f the plane the radiators (and intercoolers) helped (repeat, helped) by being behind the center of gravity. And ballast weights and moving some stuff around.
I would also note that a 2 stage Griffon compared to a Merlin III weighed just about (within 50-100lbs) as weight change going from the pair of Peregrines to the pair of Merlin XX engines. For the bare, dry engines.
Supermarine had time to sort out the Griffon installation/s and did it in two stages. They could keep making two stage Merlin powered planes while they worked.

Westland didn't have that choice.

The DH Hornet used the two stage Merlin that was longer than the single stage engines but it was a larger plane to begin with.

The Whirlwind does get Blamed for stuff that was not really it's fault. The whole propeller thing was foul up. Not just the thickness of the blades but the 20 degree pitch chance limit.
20 degrees beats fixed pitch but it is what you put on a 250mph airplane, not a 350mph airplane.
And for some reason the Whirlwind was always compared to the Spitfire for cost or materials used or using two engines. They never compared it to the Typhoon. Which was similar in size, weight and number of cylinders used and compared in armament.
They may have planned to to fit four 20mm cannon to the Spitfire but it took over 4 years to do actually do it in more than token numbers. Granted this is with hindsight. And the Typhoon only carried 20 Imp gallons more internal fuel so it wasn't going anywhere far either.

I'd say if Westland / Petters say they could have done it, then I take them at they word. I'm sure they could have made a prototype. At that point, it's always a roll of the dice. Even a good prototype can get cancelled for a variety of reasons. A test pilot can crash it and set you back 6 months. There may be small issues that cause big problems, which have to be overcome swiftly or it gets the axe. Ultimately in those days, nobody is going to know if the design is going to really work until it is produced and goes through flight testing. There is a major random element there.

The fact that their focus shifted to using the Griffon puts the project into the limbo that so many aircraft designs languished in - waiting for an engine to be fully completed. Many planes either never got made, or were made far too late to matter, because the engine wasn't ready. Sometimes it's never going to be ready, sometimes it takes several years. But designers had to think ahead and make this gamble. Using today's engine for a design which won't be flying for six months will often result in an obsolete design. That is the hard part IMO.

michaelmaltby said:

Channel Dash


No. 137 Squadron's worst losses were to be on 12 February 1942 during the Channel Dash, when they were sent to escort five British destroyers, unaware of the escaping German warships Scharnhorst and Gneisenau. Four Whirlwinds took off at 13:10 hours, and soon sighted warships through the clouds about 20 miles from the Belgian coast. They descended to investigate and were immediately jumped by about 20 Bf 109s of Jagdgeschwader 2. The Whirlwinds shot at anything they got in their sights, but the battle was against odds. While this was going on, at 13:40 two additional Whirlwinds were sent up to relieve the first four, two more Whirlwinds took off at 14:25. Four of the eight Whirlwinds failed to return.

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I seem to remember reading Whirlwind Squadron - where the Author/Pilot, really liked the aircraft. Poor blighter was taken off them and put on CAM Merchantmen flying Hurricat's whenever he wanted a swim. Those lost during the Channel Dash would have had no idea as to the strength of the German support to clear the Channel of Allied opposition.
HP52 - Foxbat

I have read whatever I can about the Whirlwind over the years and it was a very popular aircraft to fly. One piece of comfort was that they believed that it was the best RAF aircraft to an emergency landing in. The engines would be the first part of the aircraft to touch the ground with the fuselage off the ground. There was no engine in front of you so you had what we would now call a crumple zone. The frontal armour was part of the structure so that added strength to the cockpit and finally in front of that were the guns which mainly were below the pilot. Finally the pilot was situated behind the main wing spar which is the strongest part of the aircraft.
Then there was the firepower and performance both of which were very good by the standards of 1940 and two engines, always popular when flying the channel.

I think we are all in agreement in saying that the Whirlwind as designed was too small to be developed with Merlin's. Had it been designed from the start to have two Merlin engines then you could have had a real winner.

Glider said:

I think we are all in agreement in saying that the Whirlwind as designed was too small to be developed with Merlin's. Had it been designed from the start to have two Merlin engines then you could have had a real winner.

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Bingo.

If the Whirlwind were designed from the start to have Merlin's it would have been rejected.

At the time of ordering the Merlin was still a bit iffy whilst the Peregrine was regarded as a safer bet being a better Kestrel which was a known safe bet. It was, for a brief period, seen as a possible replacement for the Spitfire.

A 1,700bhp fighter was also hot stuff compared to contemporary 1,200bhp ones and developed Peregrines could have made it a 2,200bhp one so we are into Tornado/Typhoon territory and that was the replacement intended for the Hurricane and Spitfire. It certainly needed a MkII version to improve the ancillary parts of the design but the basic airframe was sound for it's task.

The step up from the Peregrine would have been the Vulture and, with the fighter market linked to the Peregrine, the Vulture could be for the heavy bomber. For the Royal Navy a Vulture Barracuda would answer its strike needs fully. The saga of the Vulture is for another thread but its issues were solvable and largely were by the time it was abandoned. Even the Firebrand could enter service without stopping to be redesigned for another engine and another role. Again a tale for another thread.

Glider said:

I think we are all in agreement in saying that the Whirlwind as designed was too small to be developed with Merlin's. Had it been designed from the start to have two Merlin engines then you could have had a real winner.

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tomo pauk said:

Bingo.

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I don't know that it was too small.

The proposed Supermarine Type 324/327, for example, used Merlins and was physically smaller, though with more wing area.

The Whirlwind was probably not sufficiently strong as it was to take the Merlins, and would have required extensive modifications to make it strong enough.

it's really just the wings that were too small, as in, not wide enough. Aspect ratio.



What it needed were wings more like this

Wild_Bill_Kelso said:

it's really just the wings that were too small, as in, not wide enough. Aspect ratio.

View attachment 711050

What it needed were wings more like this

View attachment 711049

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Changing the wing type is not a simple task. You keep pointing back to the Spitfire MkXXI. However, for that change, the wing mounting points were identical and the general size of the wing was very similar to the earlier wing types fitted to previous versions of the Spitfire.

What you're proposing is a wing that is substantially different with deeper chord, which will alter the position of the centre of pressure. That, in turn, affects airframe stability, requiring changes to the size of tail surfaces, position of the centre of gravity, length of the fuselage...or all of the above.

Enlarging a wing is not a small modification and, for the purposes of the Whirlwind, would probably result in an entirely new design with few, if any, common components to the Peregrine-engined Whirlwind.

Let's try an armed AT-9 Skyjeep. You know, the trainer deliberately designed to be too dangerous to fly.
It has engines Beaufort style.

buffnut453 said:

Changing the wing type is not a simple task. You keep pointing back to the Spitfire MkXXI. However, for that change, the wing mounting points were identical and the general size of the wing was very similar to the earlier wing types fitted to previous versions of the Spitfire.

What you're proposing is a wing that is substantially different with deeper chord, which will alter the position of the centre of pressure. That, in turn, affects airframe stability, requiring changes to the size of tail surfaces, position of the centre of gravity, length of the fuselage...or all of the above.

Enlarging a wing is not a small modification and, for the purposes of the Whirlwind, would probably result in an entirely new design with few, if any, common components to the Peregrine-engined Whirlwind.

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I never said it was simple. I'm just pointing out that is what was needed. And again, the whole version vs. variant issue to me is kind of irrelevant, what matters is how much effort it required, how quickly it could be put into assembly lines, assuming the prototype worked out.

Generally overall, as I've also noted repeatedly, it seems that the adaptation of a new engine is often the biggest sticking point causing the most delays in aircraft development.

Wild_Bill_Kelso said:

what matters is how much effort it required, how quickly it could be put into assembly lines, assuming the prototype worked out.

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And...AGAIN, it would be a LOT of effort. I keep telling you that it would be a lot of effort and you keep coming back and questioning whether it would be. Trust me...it would be a LOT of effort. You can't make a large change to something like the wing without there being a lot of knock-on consequences for other aspects of the design. IT IS A MAJOR CHANGE THAT WOULD DRIVE REDESIGN OF ALMOST ALL THE REST OF THE AIRFRAME.

Some purely FICTIONAL versions drawn up years ago:




And some alternate users (and developments):