Westland Welkin: Basis for a Whirlwind II?

[ShVAK]

The biggest problem with the Westland Whirlwind was its R-R Peregrine engines--lack of high altitude performance, unreliable (though not as bad as early Napier Sabre), limited displacement. These engines were already considered problematic even as the Whirlwind was entering service in 1940, an otherwise stellar short range fighter-bomber by all accounts with unmatched firepower by 1940 standards, excellent overall performance and good survivability.

The Welkin was a pressurized development of the Whirlwind design that used high-altitude spec Merlin 76/77 engines. Obviously the pressurized cockpit and very long (70 feet!) high aspect ratio wing which was very prone to high incidence/shock stall like the later U-2 effectively made this a completely new aircraft. But as the high altitude German bomber threat never really materialized over Britain, only 77 Welkins were built from '42 to '43.

So here's an idea--why not remove the pressurization requirement to greatly simplify the manufacturing process, design a shorter 45-50' wing based on the already successful Whirlwind, and use the Merlin 61? The Welkin had enough fuel for 1,480 mile range which would make the resulting Whirlwind II a better escort fighter (one of the original Whirlwind's design failings) and the 4 x 20mm Hispano armament in the fuselage tray was already perfect. Add some bomb/rocket racks and you have a twin engine alternative to the Typhoon and its troubled Sabre engine, an arguably better alternative to the Mosquito as a day fighter, and possibly even a V-1 interceptor.

Thoughts?

 

[davebender]

5,800 kg. P-38L. Empty weight.
3,768 kg. Welkin F Mk I. Empty weight.
3,700 kg. Fw-187A. Empty weight.


Welkin power to weight ratio should be good using RR Merlin engines.

 

[ShVAK]

The big wing compromised Welkin manueverability, though. Would it be possible to re-fit them with shorter wings or would it be necessary to go back to the drawing board?

 

[davebender]

Whirlwind was a good design. Just a bit too small. I would scale it up to accept RR Merlin engines and a larger fuel tank rather then tinker with the Welkin.

Or you could pay a Focke Wulf engineer RM 1 million to smuggle out Fw-187 blueprints. The Falke should fly just fine powered by RR Merlin engines. 8)

 

[wuzak]

You and the damn Fw 187 Dave!

I say get the Supermarine 327 going. Give it to Westlands to develop, since Supermarines are deemed too busy!

 

[ShVAK]

I say get the Supermarine 327 going.

Never heard of it. Got any specs?

 

[wuzak]

http://i69.servimg.com/u/f69/11/29/05/29/superm11.jpg
http://i39.servimg.com/u/f39/11/29/05/29/enigmw10.jpg

Aircraft              Supermarine 327
Engine(s):          2x RR Merlin 2.SM
Power:                 1265hp (944kW)
Span:                          12.2 m
Length:                        10.2 m
Wing Area:                     28.3 m²
Max Weight (kg):               5131 kg
Maximum Speed (mph):  	        465 mph
@ Altitude:           	      22000 ft
Armament:             	   6 x 20mm cannon
Wing Loading:         	     181.31 kg/m²
Power Loading:                 2.72 kg/kW

Data from British Secret Projects 1935-1949, Buttler.

The Type 327 was a follow on from the Type 324 (very similar, but with 12 x 0.303" mgs) and Type 325 (similar to Type 324 but with pusher props).

The Type 324 and 325 were in the same competition as the Hawker Tornado/Typhoon, the 327 came later when options for cannon armed fighters were required.

 

[wuzak]

The mockup of the 327

 

[wuzak]

http://i69.servimg.com/u/f69/11/29/05/29/superm10.jpg

 

[ShVAK]

Wow that's impressive. Looked like it would've given the Do 335 a run for its money.

 

[wuzak]

Bear in mind that the proposal for the Tornado/Typhoon also estimated a top speed of around 460mph.

The Type 327 would have been about the same size as the Typhoon.

 

[tomo pauk]

Judging from ther pictures drawings, Welkin's wings were far thinner than Type 327's. So the Welkin should be a better performer. More so if, as suggested at opening post, the wings lose some of it's generous wing span (from 70 to, maybe, 55 ft).
Neat bird to have above vast Asia/Pacific areas, but also in ETO/MTO.

 

[wuzak]

Judging from ther pictures drawings, Welkin's wings were far thinner than Type 327's. So the Welkin should be a better performer. More so if, as suggested at opening post, the wings lose some of it's generous wing span (from 70 to, maybe, 55 ft).
Neat bird to have above vast Asia/Pacific areas, but also in ETO/MTO.

Welkin had very high aspect ratio wings. Type 327 had low aspect ratio wings, like the Spitfire.

So "thinness" may be deceptive.

The Type 327 had a wing span, as noted above, of 12.2m, or 40ft. Much less than the Welkin.

 

[Dave Smith]

A whirlwind on test using 100 octane fuel, max allowable boost, and ROTOL propellers with a greater pitch angle managed 411 mph in lever flight and much improved altitude performance. It could of course also have been fitted with the lower drag Morris radiators which not only had lower drag but a higher cooling capacity, which potentially could have allowed higher boost to be used. The prototype flat 4 cannon nose could also carry a small auxiliary fuel tank. My brother who is building the replica whirlwing came across these gems in some development documents he has access to

 

[Ahhhhhhhhhhhhhha]

A whirlwind on test using 100 octane fuel, max allowable boost, and ROTOL propellers with a greater pitch angle managed 411 mph in lever flight and much improved altitude performance. It could of course also have been fitted with the lower drag Morris radiators which not only had lower drag but a higher cooling capacity, which potentially could have allowed higher boost to be used. The prototype flat 4 cannon nose could also carry a small auxiliary fuel tank. My brother who is building the replica whirlwing came across these gems in some development documents he has access to

Thanks for this information. Could you possibly share more details on the altitude at which the 411 mph speed was achieved?

Many thanks.

 

[yulzari]

The Welkin was built around a completely different role to the Whirlwind. The wings were comparatively thicker and overall was a bigger and heavier aeroplane. Not a route to a better Whirlwind. The Peregrine was not an unreliable engine. Westlands did determine that they could fit Merlins eventually. The fuel system needed reworking, also allowing for drop tanks and the radiators updating. The Martin Baker belt fed cannon/x12 .303" noses would get around the duration of fire limitations. The OP refers to the subject of better propellor. The CoG of Merlin's can allow for the rear fuselage to replace the original magnesium with heavier aluminium. Essentially a MkII Whirlwind is exactly that. The OTL Whirlwind but with weaknesses addressed.

Proposed alternative engines were Alison's, Wright R1820, Taurus and Merlin's. Only the Merlin could give a high altitude performance but you kick off with 2,400bhp and end up with 4,000bhp so performance is not an issue. The extra length and weight of the two stage Merlin blower can, at worst, be met with tail ballast as found on many later Spitfires.

Low down one might look to a pair of Perseus with Peregrineish power which allow the inner wing bay to be given over to fuel instead of radiators. A pair of Taurus if you want early Merlin type power. Again the Taurus was not an unreliable engine in the service used form. The Taurus was used for Naval and Coastal Command tasks over the open ocean which is not where you would accept an unreliable engine.

Now there are innumerable Whirlwind 'what if' threads and posts but building upon the Welkin base is not a route to a Whirlwind MkII. It simply would not be a Whirlwind. The Welkin is simply too big and heavy to no Whirlwind useful purpose.

 

[Dave Smith]

Thanks for this information. Could you possibly share more details on the altitude at which the 411 mph speed was achieved?

Many thanks.

Believe it was at 26,000 feet, the climb rate and altitude ceiling were also greatly improved, The info is in the in the development history in the ABI documents I am told, that my brother who is the engineer building the replica Whirlwind was going through.

 

[tomo pauk]

Believe it was at 26,000 feet, the climb rate and altitude ceiling were also greatly improved, The info is in the in the development history in the ABI documents I am told, that my brother who is the engineer building the replica Whirlwind was going through.

You will certainly understand that, in ordrer such an extraordinary claim is received as serious, actual source will be required.

 

[Dave Smith]

You will certainly understand that, in ordrer such an extraordinary claim is received as serious, actual source will be required.

Of course

Air Mistry document AVIA 15-37

It is unclear how much was tested, how much estimated, certainly Morris radiators were ordered, and RR agreed the figures quoted.
Strangely in view of past debate regarding Rotol or DH propellers, it was considered straightforward to increase the pitch angle of the DH propellers without any major problem. What might have been, but the beauracracy was tremendous!

 

[Greyman]

I think it was all estimations/calculations. Westland was never given the green light on the Mk.II.