Westland P.9 Whirlwind (1 Viewer)

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I always considered it a shame too that this pleasing aircraft was cut short that quickly.

If my memory dosn't fail me, the whirlwind was wery dependant on pneumatics (and teething troubles abounded here)which, like the rest of the design, was tailored wery carefully with the whole of the aircraft, and every change in engine would result in extensive changes all around. As noted the isentive to develope the peregrine further was small compared to fx the Merlin, and the scope for further developement was thereby small.

Actually Westland did instead go ahead with a new merlinpowered design partly inspired by the wirlwind, the Welkin, which was concieved as an high attitude fighter, but though fascinating this aircraft was far from as pleasing in appearance. Nor did it reach actual productionstatus.
 
I have wondered how a MK II Whirlwind would have done.

Belt feed guns instead of drums. A fuselage fuel tank and interconnections between the wing tanks and the fuselage. Both already being worked on.

For engines, just a MK II ( or if you will MK X) Peregrine. Just a 2 speed supercharger like the MK X Merlin and the ability to use 9-12lb of boost. It wouldn't do much for the altitude performance but at low level the thing would be a rocket.:D

I have also wondered about how much of the Story about the Peregrine being shoved aside for the Merlin was to cover up how much effort was being put into the Vulture:lol:

Granted every engine company tended to put aside their smaller engines to concentrate on the newer bigger ones.
 
At one time the Air Ministry saw the Whirlwind as the future and were not going to order more Spitfires. At that time 1,000 bhp was the maximum you could squeeze into a single engined fighter so 1,700 bhp+ was tempting and with 4x20mm cannon to boot. One can reasonably extrapolate Merlin type development to 1,300 bhp so a 2,600 bhp fighter with a loaded weighing the same as an empty P47, less frontal area and the fuel system improved and enlarged. As for the landing speed just add more runway. By the way; references to the Whirlwind keep on stating the Peregrine had problems but just what were the problems? It stayed in front line service for some years.
 
The Peregrine engine wasn't all that small. Most aircraft have some growth potential. I suspect the Whirlwind could handle an additional 83kg per wing for the more powerful Merlin engine. In fact the two engines are so close together in weight that I wonder why RR developed the Peregrine engine at all.

517kg. Peregrine I V12 engine. Liquid cooled.
590kg. DB601A V12 engine. Liquid cooled.
600kg. Merlin I engine.
 
For me the key question is whether the Whirlwind could take on German daytime fighters. To give that concept some serious consideration one would have to allow for normal stretching of the design before large scale squadron introduction. Mosquitoes entered service with a top speed of 360 mph and ended the war with a top speed of around 420mph. Is it unreasonable to extrapolate the whirlwind to a similar extent?

Mosquitoes could take on LW SE fighters with at least some hope of success, but it was a tough ask, and use of the mosquito as a daytime escort fighter was well outside its capability. It was used and very capable as a daytime intruder and fighter bomber, but never (AFAIK) as a daytime escort fighter for heavy bombers. Just didnt have the ability to fulfil that role. Could the Whirlwind have done that function....was it manouverable enough, did it or could it have the climb and dive capabilities and most importantly the range capabilities to escort British heavy Bombers in daylight operations in say 1941-2. I realize losses would have been heavy, but towards the end of '41 BC suffered its worst moments, with loss rates exceeded 7% per month. If ther was a daytime escorted raids option, feturing the Whirlwind as the escort, would that not have forced a wholesale redeployment of LW assets from the East front to Home Defence, which was a major objective of the RAF at that time. basically, would whirlwind escorted daylight raids in late '41 have been less expensive than unescorted nightime raids
 
It is not just the weight of the engines, it is the weight of the larger propellers, the larger radiators and oil coolers and other bits and pieces.

Lots of companies made a variety of engine sizes in the 30's. A number of them were dropped. Why did P&W make the R-1535 and the R-1830 14 cylinder radials? or R-985 and R-1340 9 cylinder engines. Why did Bristol make the 24.9 liter Mercury and the 28.7 liter Pegasus. better question is why did they make the 24.9 liter 9 cylinder Perseus and the 25.4 liter 14 cylinder Taurus. At least the Hercules used Perseus used the same cylinders ( at least to start).

Jumo 210s and 211s?

Hispano 12X engines and 12Y engines.

Something that receives little attention, some writers have described the Peregrine as a Merlinized Kestrel, I don't know how much of the Peregrine could be manufactured using Kestrel tooling, if any, but the Peregrine wasn't exactly all all new engine.
 
134 gallons. Whirlwind internal fuel capacity.
194 gallons. Fuel capacity of proposed Whirlwind II. This version also had Merlin engines.

For comparison purposes...
1,100 liters. Fw-187 internal fuel.
1,270 liters. Me-110 internal fuel.
410 gallons. P-38 internal fuel.

I think the proposed Whirlwind II has enough internal fuel capacity for a medium range bomber escort. Should at least reach the Ruhr and Hamburg.
 
The Peregrine engine wasn't all that small. Most aircraft have some growth potential. I suspect the Whirlwind could handle an additional 83kg per wing for the more powerful Merlin engine. In fact the two engines are so close together in weight that I wonder why RR developed the Peregrine engine at all.

517kg. Peregrine I V12 engine. Liquid cooled.
590kg. DB601A V12 engine. Liquid cooled.
600kg. Merlin I engine.

Dry weight for the more properly developed Merlin II/III crept up to 624 kg, so the weight advantage wasn't quite as small as you make out. The Merlin I was also only produced in very small numbers and wouldn't be a viable candidate for the Whirlwind.

As to why the Peregrine was developed:

The Peregrine was an outgrowth of the very successful Kestrel engine. In the mid-1930s, Rolls-Royce felt that the engine would be its major powerplant for fighters and in an X configuration as a bomber powerplant, along with another engine based on the 36 litre type R (which ended up as the Griffon) for bombers. It was a proven, reliable design that offered very good power to weight for the time.

The project the Merlin grew from was initiated later, when it was realised that there was a substantial gap between the power produced by the Peregrine (initially around 700-800 hp) and the planned 1500 hp type R derivative.

It was also felt that PV-12 (the Merlin project) was a bit of a risk. The Peregrine was initially very promising - 885 hp from 21 liters is nothing to sniff at - but it turned out that the basic Kestrel design had been taken about as far as it could be. A higher power version promising 1010 hp at +12 lbs boost with 100 octane was in development, but the engine was really too small for and the Merlin was clearly more promising. By the time the Peregrine was hitting 1000 hp, the Merlin was pushing 1450 hp.

As to why the Whirly didn't get the Merlin, well its complicated, but Petter based the aircraft around a proposed 1000 hp improved Kestrel. The wing design allowed little weight growth (the improved Kestrel design was just 480 kg) and the heavier Peregrine was already pushing the design a bit. Also, the Peregrine was a downdraft engine, fitting an updraft engine such as the Merlin required a major wing redesign.

Redesigning the Whirly for the Merlin to produce the Welkin took 80% as many design hours as producing the original Whirlwind design. Admittedly, the high alt requirement ate up a lot of this, but it was still a major job to get the larger heavier Merlin into the design.

As an aside, most interesting was the proposal to re-engine the Whirlwind with jet engines. In 1941 it was estimated that a W2B powered Whirlwind would have a top speed of at least 420 mph.
 
For me the key question is whether the Whirlwind could take on German daytime fighters. To give that concept some serious consideration one would have to allow for normal stretching of the design before large scale squadron introduction. Mosquitoes entered service with a top speed of 360 mph and ended the war with a top speed of around 420mph. Is it unreasonable to extrapolate the whirlwind to a similar extent?

Mosquitoes could take on LW SE fighters with at least some hope of success, but it was a tough ask, and ..... basically, would whirlwind escorted daylight raids in late '41 have been less expensive than unescorted nightime raids

The Mosquito was designed as a bomber, asking it to maneuver like a fighter (or climb like one) might be a bit much, even assuming the Mosquito was built to handle the same "G" loads as a single seat fighter. While the Whirlwind was designed to be a fighter it was designed to be an interceptor like the Spitfire. While extra fuel tanks were schemed for a proposed MK II version it was never going to be a long ranged fighter. While it had a large wing span (45 feet) the actual wing area was between the Spitfire and the Hurricane. With two engines to feed it was too small to carry the needed fuel. Loaded clean it was within 150lbs of P-51D with a full fuselage tank but no external stores.

Even allowing for "growth" ( two speed engines with higher boost, belt feed guns, fore and aft fuselage tanks, plus drop tanks, etc) it wasn't going to be a Germany destination escort. The MK carried 134 Imp gallons total. Even with an extra 60-70 imp gallons of internal fuel it would have been too short legged. Fuel consumption is given as 115 gallons an hour "cruising' and 151 gallons an hour all out at 15,000ft (360MPH). Range at 210mph is given as 630 miles.
 
134 gallons. Whirlwind internal fuel capacity.
194 gallons. Fuel capacity of proposed Whirlwind II. This version also had Merlin engines.

Do you have a source for the MK II with Merlins?

While the Merlins may have been proposed in passing the fitting of fore and aft fuselage tanks was more worked out and two different arrangements of 4 20mm melt feed guns were test flown. one nose section with 12 .303 guns was built (but not flown?) and another with four 20mm and three .303 guns was built.
 
Theres no way that the type could undertake LR escort on those figures. However does it use 110 gals per hour at all speeds. Assuing British bombers cruised at 250 Mph, and allowing say 20 mins loiter time, a raid to the Ruhr and back is going to take about 3 hours there and back, allowing for aiming, but not including form up time.


Taking a complete stab in the dark, if fuel consumption is reduced to an average of say 90 gals per hour, the Whirlwinds will not be able escort all the way to the target and back. you would need at least two echelons, and even so would not be able to escort all the way to the target.

Unless fuel consumption is reduced markedly at cruise speeds, there is no point to keeping the type in production, and the air ministry was more than justified to terminate it in favour of additional Spits and Hurricanes, which were cheaper and better at the SR fighter role
 
As to why the Peregrine was developed:

The Peregrine was an outgrowth of the very successful Kestrel engine. In the mid-1930s, Rolls-Royce felt that the engine would be its major powerplant for fighters and in an X configuration as a bomber powerplant, along with another engine based on the 36 litre type R (which ended up as the Griffon) for bombers. It was a proven, reliable design that offered very good power to weight for the time.

The project the Merlin grew from was initiated later, when it was realised that there was a substantial gap between the power produced by the Peregrine (initially around 700-800 hp) and the planned 1500 hp type R derivative.

The Peregrine was a devloped Kestrel - modernized and strengthened. It was designed after the Merlin and Vulture. The Merlin predated the Vulture also.

The R derivative proposed as the Griffon predated the Merlin, but didn't go very far. I doubt it was thought of as a bomber engine, since the R it was based on was very much a sprint engine. The R was itself a developed version of the Buzzard, which was a 6/5 scale Kestrel and was intended for use in bombers.

The production Griffon had nothing in common with the R/Buzzard except for sharing the bore and stroke.

Also not sure that the X engine - the Vulture - was solely intended as a bomber engine. We know the Vulture II saw service in the Manchester, but there were two versions of the Vulture intended for fighter use - Mks IV and V. The V was fitted to the Tornado prototype.


It was also felt that PV-12 (the Merlin project) was a bit of a risk. The Peregrine was initially very promising - 885 hp from 21 liters is nothing to sniff at - but it turned out that the basic Kestrel design had been taken about as far as it could be. A higher power version promising 1010 hp at +12 lbs boost with 100 octane was in development, but the engine was really too small for and the Merlin was clearly more promising. By the time the Peregrine was hitting 1000 hp, the Merlin was pushing 1450 hp.

The Peregrine was a redsign of the Kestrel which was stronger, and thus heavier, and was designed around supercharging from the begining. Some early Kestrel variants were unsupercharged.

The Peregrine was too small, and thus its power potential was limited. If they knew the extra boost that would become possible with improved fuels and thus extra power RR may have tried to keep it.

Rolls-Royce Peregrine - Wikipedia, the free encyclopedia
Four Kestrel/Peregrine cylinder banks attached to a single crankcase and driving a single common crankshaft would produce the contemporary Rolls-Royce Vulture, a 1,700-horsepower (1,300 kW) X-24 which would be used for bombers.

That is incorrect. A) The Vulture preceded the Peregrine and b) the Vulture bore spacing was different.

Also remember that by the time of the cancellation of the Vulture and Peregrine (1941) the Merlin had yet to be fully sorted and the two piece block and heads had yet to go into production.
 
For me the key question is whether the Whirlwind could take on German daytime fighters. To give that concept some serious consideration one would have to allow for normal stretching of the design before large scale squadron introduction. Mosquitoes entered service with a top speed of 360 mph and ended the war with a top speed of around 420mph. Is it unreasonable to extrapolate the whirlwind to a similar extent?

Victor Binghams book on the Whirlwind has several reports of the Whirlwind shooting down Me109's, oddly though there are also a number of reports of inconclusive combats with FW190, where both sides have disengaged?
most people tend to use the channel dash debacle as indication that the Whirlwind was not up to the job of engaging enemy S?E fighters, but that ignores the Me109's shot down prior to this engagement, which was decided by the numbers of 109's involved!
 
so it at least has one of the necessary ingredients to be a successful escort fight....the ability to engage German SE Fighters with some reasonable prospect of success.

We have to go back and look at the range issue again. Once again I would ask, what were its range characteristics when using a drop tank and travelling at normal cruise speeds. Did it, or did it not have the potential to provide long range escort to bombers.

If it does, then the british managed to chew off one their own arms when they cancelled the Whirlwind. Was the RAF so committed to night bombing that it would not even consider any alternatives?????
 
I dont think it was just range that would have made it a dubious escort, from what I have read the aircraft performed well and handled beautifully at lower level, the engagements with enemy fighters seem to have all been at low level, so maybe it could be considered in the same light as the Typhoon, keep it down low and it was a respectable performer, but as the Typhoon was coming on line at the same time Whirlwinds were nearing the end of thier service, and I doubt anyone would consider the Whirlwind as superior to the Typhoon (apart from having a second engine for over water) then I suspect the Whirlwind simply had its time?
 
Whirlwind had had it's time because two squadrons used it, and were still using about two years after production had stopped on both the airframe and engine. They may have been running out of spare parts. I don't know of too many combat aircraft that were operating in the fall of 1943 using essentially 1940 engines with no changes to superchargers or other equipment. It would be like trying to use a MK I or II Spitfire in the summer/fall of 1943. A modest improvemet to the engine could have gotten the engines up to about 1000hp apiece at low level instead of the 770hp they were rated at which would have made it a real performer at low level.
 
they were running out of airframes and engines by 43, the surviving aircraft from 263 squadron who were being re-equiped were passed on to keep the 137 squadron going, (think thats the right way round)
to be realistic, without serious development of the engine (look at all the different marks of merlin) it was always going to have a short service career, and whilst a seriously fast plane with good armament in 41 it was surpassed by several designs by 43!

always considered it a travesty that none were preserved, but maybe thats the way combat aircraft should go, in service to the end!
 
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