Westland Whirlwind revisited

[MiTasol]

The Daimler Benz DB 609 was a 16 cylinder engine based on the DB 603, and it still had the cam drive and power take-off at the ends of the engine, not in the middle.

That would produce a lot of twist in the cams

 

[Wild_Bill_Kelso]

We had another thread on Whirlwind a couple of years ago. The bottleneck seems to be the little peregrine engines. The Whirlwind was too small for a Merlin or other largish engine, it seems. We toyed with the idea of maybe Gnome Rhone but I was told it was impossible.

It was such a promising design, especially for when it came out but I think still viable well into 1942. Some minor teething problems but I think all quite resolvable. It's a shame it was basically abandoned while so many other silly designs were developed and produced in much more significant numbers.

From what I remember of the older discussion, the only way to save it would have been to set up shadow production of peregrine engines in some other factory than Rolls Royce and I was told this was impossible. Meanwhile I believe that the paltry 114 Whirlwinds which were completed were more harmful to the enemy than the 1,064 Boulton Paul Defiant, 202 Hawker Henley, 136 Blackburn Roc, 570 Blackburn Botha, and 220 Blackburn Firebrands produced combined.

On the other hand, the Beaufighter, while a bit slower and maybe not quite as effective in a dogfight against top land based fighters, was a much more useful aircraft overall, especially thanks to it's range, and was probably the natural successor.

 

[Wild_Bill_Kelso]

I wonder if Eric Brown tested one? Wonder what he thought of them?

he didn't like it. But he wasn't always right!

 

[GrauGeist]

The Welkin did prove that Merlins could be used, with modifications to the aircraft, of course.

 

[tomo pauk]

The Welkin did prove that Merlins could be used, with modifications to the aircraft, of course.

On what aircraft?

 

[SaparotRob]

The one with the Merlins?

 

[EwenS]

The one with the Merlins?

The Welkin was significantly larger than the Whirlwind (the Wiki data on it simply repeats that of the Whirlwind in some areas).

Whirlwind / Welkin I
Span - 45 / 70ft
Length - 32 / 42.5ft
Wing area - 250 / 460 sq ft
Max weight - 10,270-11,445 (depending on source) / 19,775lb

The Welkin was a huge bird for a fighter and designed to operate at high altitudes like the Vickers Type 432 & Mosquito Mk.XV.

 

[GrauGeist]

This was also in my comment:

with modifications to the aircraft, of course.

Yes, the Welkin was larger for several reasons.

But it was essentially a Whirlwind redesigned.

 

[tomo pauk]

Yes, the Welkin was larger for several reasons.

But it was essentially a Whirlwind redesigned.

New wing, new fuselage, new fuel tankage, new engines, new layout of where the cockpit/weapons/ammo goes, new radiators, new oil system, new wheels - I'd say Wekin was a new aircraft.

 

[Wild_Bill_Kelso]

The question is, could you have either modified the Welkin with lower alt - rated merlins and shorter wings, and voila you have a merlin powered Whirlwind? Or would you need more extensive changes (again).

God knows they wasted nice Merlin engines on a lot of pretty well pointless aircraft.

 

[Wild_Bill_Kelso]

Scale comparison of Welkin to Whirlwind

 

[tomo pauk]

The question is, could you have either modified the Welkin with lower alt - rated merlins and shorter wings, and voila you have a merlin powered Whirlwind?

That would still be a Welkin.

God knows they wasted nice Merlin engines on a lot of pretty well pointless aircraft.

Sad, but true.

 

[Wild_Bill_Kelso]

That would still be a Welkin.

I mean, you can call it a Zebra, the question to me would have been, do you have a viable low or medium altitude fighter that you can use. Using merlins.

One thing that looks quite nice about the Welkin is a greatly enhanced range. I assume some of that is from flying at much higher altitude, some due to the extra space provided by a 70' wingspan. But if they figured out how to fit more fuel in the equivalent wing area as the Whirlwind or something similar (it would have to be probably close to that size and wingspan to have that useful speed) then you'd already have a Whirlwind which was much better.

Sad, but true.

 

[tomo pauk]

I mean, you can call it a Zebra, the question to me would have been, do you have a viable low or medium altitude fighter that you can use. Using merlins.

It probably would've been.

One thing that looks quite nice about the Welkin is a greatly enhanced range. I assume some of that is from flying at much higher altitude, some due to the extra space provided by a 70' wingspan. But if they figured out how to fit more fuel in the equivalent wing area as the Whirlwind or something similar (it would have to be probably close to that size and wingspan to have that useful speed) then you'd already have a Whirlwind which was much better.

Increase in range was due to the Welkin having 520 imp gals on board (2 x 220 in the wings outboard of the nacelles, plus 80 gals in the fuselage). Whirly was with 134 imp gals of internal fuel in the two fuel tanks outboard the nacelles.

 

[Wild_Bill_Kelso]

So maybe you can add the 80 gallon tank in the fuselage though I don't know how good that is for stability.

I assume Merlin engines will use more fuel than Peregrine?

 

[don4331]

Installing Merlins in Whirlwind is like installing Sabre in Hurricane - you lift out pilot's seat, and slide a whole new airplane underneath. While you're at it, give the airplane a new name.

And you completely retool the factory and have supplier base do the same to build the new airplane - it only takes 2 years, there being a war on and all.

p.s. Welkin doesn't address the "Achille Heel" of the Whirlwind design - that being compressibility caused by horizontal stabilizer and fin interaction (both surfaces are airfoils, so accelerating airflow in 2 dimensions)

 

[Just Schmidt]

Installing Merlins in Whirlwind is like installing Sabre in Hurricane - you lift out pilot's seat, and slide a whole new airplane underneath. While you're at it, give the airplane a new name.

Absolutely have to disagree. Changing minor details as engines, weapons, wing size, building materials and avionics is largely irrelevant for the real chracteristics of an aircraf, the unique qualities lies in the name.

 

[GrauGeist]

Some aircraft did take very well to an engine change.

While the P-51 might be used as an example, it's not a good one, since the Allison and Merlin were comparable in size.

However, the KI-61's switch from the inline Ha40 to the radial Ha112 is a good example.

So too, would be the Fw190's switch from the radial BMW801 to the inline Jumo213.

 

[tomo pauk]

Some aircraft did take very well to an engine change.

While the P-51 might be used as an example, it's not a good one, since the Allison and Merlin were comparable in size.

However, the KI-61's switch from the inline Ha40 to the radial Ha112 is a good example.

So too, would be the Fw190's switch from the radial BMW801 to the inline Jumo213.

Agreed pretty much.
We can also see the Bf 109 having no problems with jump from the small Jumo 210 to the big DB 601. By the time we see all new fuselage, new wing, a major powerplant change - this is a new aircraft, not just version of a legacy A/C. Talk Fury vs. Hurricane, Hurricane vs. Typhoon, Wildcat vs. Helcat, Hellcat vs. Bearcat, Ki 21 vs. Ki 43, A5M vs. A6M...

 

[Wild_Bill_Kelso]

I think you meant Ki 27 to Ki 43, though other than that i agree. I think it's a roll of the dice when you change anything as fundamental as an engine, especially (but not only) where things like superchargers and cooling systems may also change. Bigger engines also typically mean need to store more oil and fuel.