Westland Whirlwind revisited (1 Viewer)

[tomo pauk]

Myself, I like the Me 262 best - the jet-powered version of the Bf 109.

 

[Wild_Bill_Kelso]

Sure, that's exactly the same correlation.

 

[Wild_Bill_Kelso]

Modify the Welkin, modify the Whirlwind. Either way, you'll need different / modified wings. Otherwise neither design is viable going forward because they won't make more Peregrines and the Whirlwind's wing is too small as-is for merlins, and nobody needs the Welkin's 70' wing (or pressurized cockpit).

But I'm not sure a new wing is a 3 or 4 year project.

The biggest problems with most new aircraft variants or types in WW2 seems to me to have been the engines. That was the biggest issue with the XP-58 IIRC. In this case you are using a proven engine so that's not going to be hung up on that.

 

[GrauGeist]

de Havilland tapped into the Mosquito's design to build the Hornet, which was actually smaller, in this case.

 

[wuzak]

I don't see the Welkin as anywhere near the same kind of degree of change from a Whirlwind as a P-51 to an FJ-1. I don't think that is an honest comparison.

I think the point SR6 is making is that almost everything was changed on the Welkin compared to the Whirlwind.

I mean, is a Spitfire Mk XXI the same thing as a Spitfire Mk I? How many changes were there? They put multiple different engines into a D4Y, or a Beaufighter, does that make them different planes?

The Spitfire XXI still had most of the fuselage common with earlier versions. The main difference was the new, stronger, wing.

The Beaufighter just had engine changes. The only airframe change I know of was that the tail planes were given dihedral to compensate for directional instability when fitted with Merlins. That change remained with subsequent variations.

I realize changing a wing is a bigger deal than changing an engine. How long does it take to make a slightly lower aspect ratio wing for the Whirlwind?

It depends.

The Spitfire had a few different wings fitted - the original one and its variations, the new wing for the 21, and the trapezoidal laminar flow wing of the Spiteful.

To change the engine required new bodywork ahead of the firewall and strengthened longerons (made of steel instead of aluminium IIRC), as well as the need to increase the fin/rudder area.

 

[MiTasol]

But the Welkin was a MUCH LARGER airframe. If you have a narrow firewall built just big enough to accommodate the engine bearers for an engine of a given width, then it takes a LOT of redesign to fit a wider engine into that space, either by odd geometry for the engine bearers or implementing a brand new firewall which means a redesign for the entire nacelle.

It's much easier to do if you start with a larger airframe that's actually designed to accept wider engines. It's much harder to do starting small and going larger.

A redesign of the nacelle would also be required to carry the larger landing gear and wheels and brakes.

Agree it would be

much easier to do if you start with a larger airframe that's actually designed to accept wider engines. It's much harder to do starting small and going larger.

 

[MiTasol]

I don't see the Welkin as anywhere near the same kind of degree of change from a Whirlwind as a P-51 to an FJ-1. I don't think that is an honest comparison.

I mean, is a Spitfire Mk XXI the same thing as a Spitfire Mk I? How many changes were there? They put multiple different engines into a D4Y, or a Beaufighter, does that make them different planes?

View attachment 710320

View attachment 710319

Somehow both of those are D4Ys.

View attachment 710321
That's a Beaufighter

and so is that
View attachment 710322

To me the designation is fairly irrelevant, The question is, could you make it work, in time. In the case of the D4Y, the answer is ... not really. For the Beaufighter, the answer is yes indeed.

I realize changing a wing is a bigger deal than changing an engine. How long does it take to make a slightly lower aspect ratio wing for the Whirlwind?

The only major difference between the two Beaufighter's is firewall forward - the wing fuselage and tail are all exactly the same. Other changes were limited to instrumentation and engine controls.

To put a Merlin in a Whirlwind you need a whole new wing and a whole new landing gear and a whole new cooling system and a whole new fuel system and to extend the rear fuselage which means a major redesign of the fuselage as additional structure must be added not only to extend the fuselage but probably to reflect the longer moment arms of the tail on the "original" fuselage.

 

[MiTasol]

Many aircraft had lengthened fuselages.



I'd say an A-26 was indeed a modified A-20, it was just modified enough that they decided to give it a new designation.



That's good enough for me right there!

And not one structural component of the A-20 is used on the A-26 and the empty weight is 50% more so that makes it a totally new design.

Using your claim that the A-26 is a submodel of the A-20 makes the DC-4 is a DC-3 submodel

 

[Wild_Bill_Kelso]

The only major difference between the two Beaufighter's is firewall forward - the wing fuselage and tail are all exactly the same. Other changes were limited to instrumentation and engine controls.

To put a Merlin in a Whirlwind you need a whole new wing and a whole new landing gear and a whole new cooling system and a whole new fuel system and to extend the rear fuselage which means a major redesign of the fuselage as additional structure must be added not only to extend the fuselage but probably to reflect the longer moment arms of the tail on the "original" fuselage.

They did it with the Welkin... and a Westland designer said it could be done directly to the Whirlwind.

 

[SaparotRob]

I think you guys are being trolled.

 

[Wild_Bill_Kelso]

If you can put a different wing and a (very) different engine on a Sptifire, and still call it a Spitfire, you can put a different wing and a different engine on the Whirlwind, and I couldn't care less what you call it.

 

[Shortround6]

I think you guys are being trolled.

I agree and I am out of this part of the discussion.

 

[Wild_Bill_Kelso]

I think some of y'all are really not as smart as you think you are and take yourselves a little too seriously on top of that.

 

[Wild_Bill_Kelso]

Anyway, I for one was not trolling. I think the issue of how much modification to an aircraft, particularly the wing it seems, is rather fraught, as is any discussion of any kind of "What If" scenario in WW2 aviation, because a lot of people get cross over the fact that "What If" is inevitably based on something that didn't in fact happen. I think that is why we created a separate category for "What If".

It's quite often the case that "What If" scenarios around fixing planes that seemed to have promise but never quite found their lane either at all, or after a certain point in the war, that the main issue has to do with the wing. The only way to have fixed the Hurricane for example, would have been a new wing. But I guess that makes it not a Hurricane? How long does it take to make a new wing? North American seemed to make a very good new wing rather quickly.

I'm not entirely clear what defines the difference between a new model vs. a new variant. It does seem arbitrary to me. Yak 7 and Yak 9, very similar, but different models. Spit 1 and Spit 21, not so similar, but the same model, just different variants. P-51A and B look very similar, but internally they are quite different. I would call them different aircraft. The A-36 is labeled as a different aircraft, due to dive brakes and a bomb cradle. Other than that, it's very similar to a P-51A isn't it? What are the criteria exactly? It's not a "troll" question.

And maybe I need better glasses. It really may be the case. My vision isn't what it used to be. But the Whirlwind and the Welkin look very similar to me. Not just "made by the same design firm" but real close. I don't know how to quantify that, but I'd be very surprised if it's true as Shortround6 claimed that there isn't a single part shared between the two aircraft. Aside from the super long wings on the Welkin, I would compare it to the difference when looking at a P-36 and a P-40F side by side.

I don't have a scale model of the Welkin but I do have a Whirlwind, and a bunch of others in the same scale to compare it to (which is part of why I made a bunch of planes from the same period in the same scale, because photos often don't give you the perspective of relative size). Whirlwind has small wings, no doubt about it, and it's a small aircraft. The only twin engined planes on my shelves which compare in size are the Breuget 693 and the Ki-46, but the Whirlwind has thinner wings in terms of aspect ratio than both of those.

P-38 and Mosquito look bigger but not vastly bigger, more like maybe about 20%. Beaufighter looks a lot bigger.

The engine nacelles on the Whirlwind don't actually look that small to me. Maybe the scale is off on my (Airfix) model but these nacelles look actually a bit bigger than the ones on the Pe-2 and not a whole lot smaller than the ones on my Mosquito Mk IV.

Finally, I wasn't trying to get into an argument about what amount of changes constitutes a new variant vs. a new model of aircraft. I was simply interested in whether Westland had the ability to make a fighter based on (or originating with) the Westland design which incorporated merlins, since the peregrine was a dead end, and they had plenty of merlins being used on other aircraft that weren't necessary.

 

[Dimlee]

Myself, I like the Me 262 best - the jet-powered version of the Bf 109.

Of the Bf 110. They just dropped the gunner and made the tail smaller because there was a deficit of materials.
I think I should put this on Wiki...

 

[SplitRz]

Anyway, I for one was not trolling. I think the issue of how much modification to an aircraft, particularly the wing it seems, is rather fraught, as is any discussion of any kind of "What If" scenario in WW2 aviation, because a lot of people get cross over the fact that "What If" is inevitably based on something that didn't in fact happen. I think that is why we created a separate category for "What If".

It's quite often the case that "What If" scenarios around fixing planes that seemed to have promise but never quite found their lane either at all, or after a certain point in the war, that the main issue has to do with the wing. The only way to have fixed the Hurricane for example, would have been a new wing. But I guess that makes it not a Hurricane? How long does it take to make a new wing? North American seemed to make a very good new wing rather quickly.

I'm not entirely clear what defines the difference between a new model vs. a new variant. It does seem arbitrary to me. Yak 7 and Yak 9, very similar, but different models. Spit 1 and Spit 21, not so similar, but the same model, just different variants. P-51A and B look very similar, but internally they are quite different. I would call them different aircraft. The A-36 is labeled as a different aircraft, due to dive brakes and a bomb cradle. Other than that, it's very similar to a P-51A isn't it? What are the criteria exactly? It's not a "troll" question.

And maybe I need better glasses. It really may be the case. My vision isn't what it used to be. But the Whirlwind and the Welkin look very similar to me. Not just "made by the same design firm" but real close. I don't know how to quantify that, but I'd be very surprised if it's true as Shortround6 claimed that there isn't a single part shared between the two aircraft. Aside from the super long wings on the Welkin, I would compare it to the difference when looking at a P-36 and a P-40F side by side.

I don't have a scale model of the Welkin but I do have a Whirlwind, and a bunch of others in the same scale to compare it to (which is part of why I made a bunch of planes from the same period in the same scale, because photos often don't give you the perspective of relative size). Whirlwind has small wings, no doubt about it, and it's a small aircraft. The only twin engined planes on my shelves which compare in size are the Breuget 693 and the Ki-46, but the Whirlwind has thinner wings in terms of aspect ratio than both of those.

P-38 and Mosquito look bigger but not vastly bigger, more like maybe about 20%. Beaufighter looks a lot bigger.

The engine nacelles on the Whirlwind don't actually look that small to me. Maybe the scale is off on my (Airfix) model but these nacelles look actually a bit bigger than the ones on the Pe-2 and not a whole lot smaller than the ones on my Mosquito Mk IV.

Finally, I wasn't trying to get into an argument about what amount of changes constitutes a new variant vs. a new model of aircraft. I was simply interested in whether Westland had the ability to make a fighter based on (or originating with) the Westland design which incorporated merlins, since the peregrine was a dead end, and they had plenty of merlins being used on other aircraft that weren't necessary.

I don't know how to quantify that, but I'd be very surprised if it's true as Shortround6 claimed that there isn't a single part shared between the two aircraft.

Whirlwind:
Length: 32 ft 3 in (9.83 m)
Wingspan: 45 ft 0 in (13.72 m)
Height: 11 ft 0 in (3.35 m)
Wing area: 250 sq ft (23 m2)
Airfoil: root: NACA 23017; tip: NACA 23008
Empty weight: 8,310 lb (3,769 kg)
Gross weight: 10,356 lb (4,697 kg)
Max takeoff weight: 11,445 lb (5,191 kg)

Welkin:
Length: 41 ft 6 in (12.65 m)
Wingspan: 70 ft 0 in (21.34 m)
Height: 15 ft 9 in (4.80 m)
Wing area: 250 sq ft (23 m2)
Airfoil: root: NACA 23021; tip: NACA 23015[14]
Empty weight: 8,310 lb (3,769 kg)
Gross weight: 10,356 lb (4,697 kg)

All key areas are hugely different (thought the Welkins similar weight came as a big surprise to me!)

The two shared the same designer - the famous Mr Petter, so any design similarity is probably down to that, and no more unusual or indicative than the designs of de Havilland or Hawker sharing common form.

Wikipedia for once gives us the most important clue: "Westland put forward their P.14, essentially an adaptation of Westland's Whirlwind fighter layout." Stress on layout. I don't take from that it was a design adaptation of the Whirlwind airframe, but that is was essentially a new (but similar in appearance) design

But all said and done, I do kinda take your point. But looking at all of the photographs in combination with the above specs, I'd lay money on their not sharing any common components except perhaps cockpit fittings and instrumentation.

 

[Shortround6]

All key areas are hugely different (thought the Welkins similar weight came as a big surprise to me!)

That is because the author of the wiki article either copied some of the Whirlwind data or copied a website that did.

Whirlwind:
Length: 32 ft 3 in (9.83 m)
Wingspan: 45 ft 0 in (13.72 m)
Height: 11 ft 0 in (3.35 m)
Wing area: 250 sq ft (23 m2)
Airfoil: root: NACA 23017; tip: NACA 23008
Empty weight: 8,310 lb (3,769 kg)
Gross weight: 10,356 lb (4,697 kg)
Max takeoff weight: 11,445 lb (5,191 kg)
Red is correct for the Whirlwind.

Welkin:
Length: 41 ft 6 in (12.65 m)
Wingspan: 70 ft 0 in (21.34 m)
Height: 15 ft 9 in (4.80 m)
Wing area: 250 sq ft (23 m2) 460 sq ft (42.7 m2)
Airfoil: root: NACA 23021; tip: NACA 23015[14]
Empty (Tare)weight: 8,310 lb (3,769 kg) 11,974 lb (5431 kg)
Gross weight: 10,356 lb (4,697 kg) 19,775 lb (8969 kg)
Red is wrong for the Welkin Green is correct.
Figures are from "The British Fighter since 1912"
The 1946 Jane's gives 17,500lbs for loaded weight. The British Fighter since 1912 lists the weight as "all up".
Your sources may differ
There were some rather large long range tanks tested, I don't know if they were issued.

Interesting detail from 1946 'Jane's'
Due to the wing loading expected on the Welkin (38lb sq/ft) they reverted back to a split flap instead of the Fowler flap used on the Whirlwind.
Quite a bit of space is used describing the cabin pressure system and the Westland automatic valves used to control the cabin pressure.

There was a Welkin MK II two seater that was quite a bit heavier.

 

[Wild_Bill_Kelso]

That looks like more accruate information for sure. I noticed that the wing area for the Welkin was 250 on the Wiki and I knew that couldn't be right.

 

[Wild_Bill_Kelso]

So what if we say, put in a NACA 24015 root / 23010 tip

 

[MiTasol]

But all said and done, I do kinda take your point. But looking at all of the photographs in combination with the above specs, I'd lay money on their not sharing any common components except perhaps cockpit fittings and instrumentation.

As others who have far more knowledge of the two types have indicated the differences in dimensions and construction methods indicates that no major Whirlwind structural parts are used on the Welkin. Major parts include wings, wing tips, flaps, control surfaces, tailplane and fin, fuselage and can include gun bay doors, etc

To say no parts are interchangeable is an over simplification. The correct statement would be no major Whirlwind structural parts were used. Hundreds of Westland and British standard parts (AM, AS and AGS) would be common to both types such as instruments, nuts, bolts, hydraulic fittings, control fittings, etc as well as Westland standard parts which may include things as diverse as fuel caps, service panels, placards, control levers, coolant and hydraulic fittings. I do not know how many Westland standard parts there were but Bristol had over 2000 standard airframe components as well as many engine standards.