Westland Whirlwind revisited

We have a number of threads on the light fighter theory, here is one.

Lightweight fighter: how would've you done it?

I would note that the Arsenal VG-33 often gets mentioned in discussions of "light fighters". It grossed 5850lbs which is light by later standards but it first flew in April of 1939. Spitfire I's were under 6000lbs at the time?
P-36C which is older had a normal gross weight (105 US gallons on board) of 5600lbs.

using a 150 sq ft wing on a 5800lb airplane is hardly going to give you good maneuverability even if it helps speed.

Admiral Beez said:

As a previous decade-long owner of a 1960s Triumph motorcycle with Whitworth and other CEI fasteners, plus an early 1980s Suzuki shafty, I must give kudos to those WW2 mechanics which may have to maintain a mixed force of European metric, American imperial and British aircraft. The Russians with all the Lend Lease types must have been kings at this.

Such as the DEI air force, with Martin bombers and Brewster fighters from USA, Dornier flying boats from Germany and in the end Hawker Hurricanes from Britain. Those Dutch mechanics must have had comprehensive tool boxes and knowledge.

Click to expand...

It could be irritating sometimes working on mixed Imperial/Metric fasteners. Late 60s early 70s British motorbikes could be a nightmare it sometimes felt like the production line had a mixed bag of taps and Dies and the worker just picked up whatever happened to be nearest.

Early Japanese motorbikes could also cause stress they were Metric but on some makes it was JIS (Japanese Industry Standard) Metric which normally matched ISO Metric but there were enough differences to catch the unwary apprentice mechanic (that was me). An ISO thread bolt could strip a JIS thread if the monkey on the other end of the tool went a bit too happy with the torque. Also Japanese X head screws were not the same as Phillips X head leading to many a butchered screw head when the screwdriver slipped, butchered brake master cylinder cap screws were a regular sight.

You soon got to recognise most standards it just meant your tool cabinet was bigger.

Admiral Beez said:

As a competitor to the Whirlwind, was an enlarged, military spec version of the 1934 de Havilland DH.88 Comet ever considered for the twin engined, single seat fighter role?

Click to expand...

No, but the DH 91 was a sort of distant ancestor of the Mosquito. Both the company and the Air Ministry were interested in a twin Merlin 'Albatross' to P.13/36. There was some interest in adapting the DH 95 'Flamingo'.

I think the DH 88 was too old, and the Whirlwind had first flown in 1938 almost a year before the war.

It must be noted that to develope an engine is much more time and resources consuming than that of a medium sized airframe, let alone to mass produce it, in the pre-war years as it is today.
Let's remember the history of L-1011 and RB-211...
So the RR decision to drop Peregrine, an engine with no potential of development, was more than wise, BMPPOW.
Certainly can't be said that to adapt quite a different engine to an exixting airframe is always unfeasible or (P-51, Re-200 >RE 2001 etc: Germans succesfully adapted a DB 605 to a Spitfire airframe...) but, more often than not it is better to use a blank piece of paper and to design another "right" airframe with the "right" engine.

The thing is, at least as often as not, the 'right' engine didn't work out, and instead languished in development hell for god knows how long, promising fantastic performance but remaining just out of reach by refusing to run reliably, (i.e. Naiper Sabre) resulting in a promising and potentially useful aircraft either showing up too late or being cancelled, and wasting countless man hours and resources trying to overcome fundamental design flaws. This happened over and over and over again in every Great Power involved in the war.

Once you have a proven engine that is free of major* design flaws and faults, it therefore makes sense not to abandon it too lightly. Sure if you aren't certain what to do with it put it on the back-burner, but if you have an engine powering a successful combat aircraft, I wouldn't cancel it outright. Of course, they didn't know Whirlwind would turn out so good or that other projects would have so many problems. This is why hindsight is more prescient obviously.

Some of the best aircraft of the war were created by merging a proven engine that performs as needed to an existing airframe stuck with a less than ideal engine, the classical example being the P-51. Another is the LaGG-3 and the La-5.

I think the War Ministry, RR etc. were operating on assumptions which we can now see from hindsight were not entirely correct. Not all of the future designs were going to be big birds, and small fighters remained on the front line to the end of the war. In fact I'm sure they could have found more uses for Peregrines, at the very least you could put them on a lot of lighter aircraft which were still widely used and give them a performance boost thereby. Avro Anson for example. Blackburn Skua might have gotten a new lease on life. Even the Lysander might have been more useful with a Peregrine, it would have probably been faster.

If you could boost power a little bit I could see a Peregrine being a useful powerplant for a Blenheim or a Hampden.


All that is just speculation of course. The bottom line historical fact which has been repeated over and over but still bears emphasizing - is that the British wasted resources on aircraft that ultimately proved to have virtually zero impact on the war effort and in many cases cost more lives than they saved. Defiant has it's fans around here I know, but not many people really wanted to pilot one into combat after the first few sorties. Blackburn Roc was even worse. Henley was a waste of time - there were plenty of old obsolete planes that could act as target tugs you didn't need to build 200 more. Lysander was marginal at best, certainly there was no need to produce so many (over 1,700). Did they really need to keep making (over 4,000) Blenheims into 1943? And so on.

RR obviously had their reasons to cancel the Peregrine, but that could have been overriden. It's not some unforgivable Sin because every country made mistakes like that. But cancelling the Whirlwind was indeed a mistake, in hindsight.

*Peregrine had some minor problems but so far as I'm aware it was a fundamentally sound design.

Elmas said:

So the RR decision to drop Peregrine, an engine with no potential of development, was more than wise,

Click to expand...

It might be better to say that the Peregrine, while it had potential for development, had no real market for sales. What was the market for a developed 1000-1100hp Peregrine when you take an off the shelf 1000-1100hp Merlin for just a bit more size and weight? And the Merlin might last longer between overhauls being lower stressed.

This is the reason that P&W dumped the R-1535. The number of people/customers/airplane makers that wanted a smaller, lighter R-1830 wouldn't support the R&D effort needed to "develop" it to higher powered versions.

AS planes grew bigger and added more "stuff" the smaller engines fell by the wayside. Even post war P & W misjudged the market and tried to build a 14 cylinder R-2180 using about 1/2 of the R-4360 but the airlines either wanted twins powered by R-2800s (more seats) or were satisfied with war surplus planes using older engines (much cheaper).

the idea that engine makers needed to offer a wide range of engines and powers fell by the wayside and most airframe makers went for the most powerful engines they could get.

Shortround6 said:

the idea that engine makers needed to offer a wide range of engines and powers fell by the wayside and most airframe makers went for the most powerful engines they could get.

Click to expand...

If it was really that simple they would have put an R-2800 on a P-51 or a Spitfire, more power is always better right? Or a Jumo 213 on a Bf 109. But that would have defeated the purpose by cancelling out the benefits of the smaller airframes.

Schweik said:

The thing is, at least as often as not, the 'right' engine didn't work out, and quite often it languished in development hell for god knows how long, resulting in a promising and potentially useful aircraft either showing up too late or being cancelled, and wasting countless man hours and resources trying to overcome fundamental design flaws. This happened over and over and over again.

Once you have a proven engine that is free of major* design flaws and faults, it therefore makes sense not to abandon it too lightly.

Some of the best aircraft of the war were created by merging a proven engine that performs as needed to an existing airframe stuck with a less than ideal engine, the classical example being the P-51. Another is the LaGG-3 and the La-5.

I think the War Ministry, RR etc. were operating on assumptions which we can now see from hindsight were not entirely correct. Not all of the future designs were going to be big birds, and small fighters remained on the front line to the end of the war. In fact I'm sure they could have found more uses for Peregrines, at the very least you could put them on a lot of lighter aircraft which were still widely used and give them a performance boost thereby. Avro Anson for example. Blackburn Skua might have gotten a new lease on life. Even the Lysander might have been more useful with a Peregrine, it would have probably been faster.

If you could boost power a little bit I could see a Peregrine being a useful powerplant for a Blenheim or a Hampden.


All that is just speculation of course. The bottom line historical fact which has been repeated over and over but still bears emphasizing - is that the British wasted resources on aircraft that ultimately proved to have virtually zero impact on the war effort and in many cases cost more lives than they saved. Defiant has it's fans around here I know, but not many people really wanted to pilot one into combat after the first few sorties. Blackburn Roc was even worse. Henley was a waste of time - there were plenty of old obsolete planes that could act as target tugs you didn't need to build 200 more. Lysander was marginal at best, certainly there was no need to produce so many (over 1,700). Did they really need to keep making (over 4,000) Blenheims into 1943? And so on.

RR obviously had their reasons to cancel the Peregrine, but that could have been overriden. It's not some unforgivable Sin because every country made mistakes like that. But cancelling the Whirlwind was indeed a mistake, in hindsight.

*Peregrine had some minor problems but so far as I'm aware it was a fundamentally sound design.

Click to expand...

Rolls Royce simply did as the Air Ministry told them.

Well, that's what I would assume anyway in a wartime situation. Some suggestion in here that RR could do as they pleased.

Schweik said:

Once you have a proven engine that is free of major* design flaws and faults, it therefore makes sense not to abandon it too lightly...

Click to expand...

Nor does it make sense under war time contingency to keep an engine in production that will reduce the output of the most useful engine, what Hives refereed to as the 'standard engine'. That was the Merlin.

Schweik said:

I think the War Ministry, RR etc. were operating on assumptions which we can now see from hindsight were not entirely correct. Not all of the future designs were going to be big birds, and small fighters remained on the front line to the end of the war.

Click to expand...

Small fighters did indeed remain on the front line until the end of the war and guess what? The two best, Spitfire and P-51 used Merlins.

Schweik said:

The thing is, at least as often as not, the 'right' engine doesn't work out, and quite often it languishes in development hell for god knows how long, resulting in a promising and potentially useful aircraft either showing up too late or being cancelled. This happened over and over and over again.

Once you have a proven engine that is free of major* design flaws and faults, it therefore makes sense not to abandon it too lightly.

Some of the best aircraft of the war were created by merging a proven engine that performs as needed to an existing airframe stuck with a less than ideal engine, the classical example being the P-51. Another is the LaGG-3 and the La-5.

I think the War Ministry, RR etc. were operating on assumptions which we can now see from hindsight were not entirely correct. Not all of the future designs were going to be big birds, and small fighters remained on the front line to the end of the war. In fact I'm sure they could have found more uses for Peregrines, at the very least you could put them on a lot of lighter aircraft which were still widely used and give them a performance boost thereby. Avro Anson for example. Blackburn Skua might have gotten a new lease on life. Even the Lysander might have been more useful with a Peregrine, it would have probably been faster.

If you could boost power a little bit I could see a Peregrine being a useful powerplant for a Blenheim or a Hampden.

Click to expand...

Most of those alternatives need to much engineering for too little result.

the Anson for example was a modified light plane or feeder airliner (pilot and 6 passengers? or 2 crew and 4 passengers?) and did gain over 50% in power in it's life. going to triple power is simply going to burn up the payload (unless you change the structure) and overstress the airframe.


pair of 290hp engines with fixed pitch props.

Canadian Built examples of the Anson/Oxford had engines of up to 450hp installed (P&W R-995 Wasp Juniors) as did some of the British built planes.

Nothing was going to save the Lysander, not even an R-2800

Skua might have been saved by using the R-1830, You needed an engine comparable to the engine in the SPD, the Peregrine is too little and too late.
For a viable combat plane you need two Peregrines. Which is a somewhat viable trade off vs the Sabre engine. It is not a viable alternative to higher powered Merlin's or Griffins.

Perhaps if Bristol wasn't mucking about with the Taurus (and Perseus) they could have put a bit more work into the Mercury and Pegasus.
The Pegasus used in the Hampden and Wellington used a two speed supercharger and could hit 1000hp when running on 100 octane fuel.

They never got updated cooling fins like even the 1200hp Cyclones got (let alone later Cyclones).

stona said:

Nor does it make sense under war time contingency to keep an engine in production that will reduce the output of the most useful engine, what Hives refereed to as the 'standard engine'. That was the Merlin.

Click to expand...

And yet so many Merlins were being wasted on bad or flawed airframes.

Small fighters did indeed remain on the front line until the end of the war and guess what? The two best, Spitfire and P-51 used Merlins.

Click to expand...

True but P-51s were of very limited use until Merlin 60's were put on them, and Spitfires were knocked back a peg by Fw 190s as we all know for a crucial period in the beginning (or lets say, end of the beginning) of the war before it got the two stage Merlins, and that is actually one of the places where I think Whirlwind could have been very helpful.

I'd also call P-51 and Spitfire 'medium' sized fighters though Spit is closer to a small one than the P-51 is. Certainly both are small next to a Tempest or a P-47.

Schweik said:

If it was really that simple they would have put an R-2800 on a P-51 or a Spitfire, more power is always better right? Or a Jumo 213 on a Bf 109. But that would have defeated the purpose by cancelling out the benefits of the smaller airframes.

Click to expand...

It is not quite so simple. The R-2800 was great lump of an engine, even the engine in an early B-26 went 2270lbs with a two speed single stage supercharger. and it needs a huge propeller to turn that power into thrust. It just won't fit/balance in some of the smaller airframes. You have to throw out so much you might as well start over.


The 109 had a number of problems which get glossed over. It was designed around a 700hp engine (roughly) the Jumo 210, many people forget that somewhere around 1000 109s were built with Jumo 210 before the DB 601 showed up. The timeline is a little too long for it to be quite believable that the 109 was designed around the DB 600 and all of these aircraft were 'fillers' just waiting for the DB engine to show up. The BF 110 first flew 50 weeks after the 109 and the idea that it was designed for the DB series engines is a bit more believable.
The 109 also needed considerable modifications to fit the DB 601. Trying to change a 109D to an 109E in the field would have been nearly impossible.

I am not sure where your definition of small, medium and large come from. Certainly the Spitfire has a skinner fuselage than the P-51 but the Spit actually has a slightly larger wing. The radiators, oil coolers and intercooler (on the two stage engines) is also hanging out under the wings (ok part of the cooling matrix is in the wing) vs the Mustang housing a large part of the cooling matrix inside the fuselage. The Mustang has the famous larger fuel capacity (forgetting the rear fuselage tank/s) increased weight but not bulk by much (thicker wing roots)

Part of the Problem the Spits had with the FW 190 is that no first line Spitfire fighter ever had a single stage two speed supercharger. Had they fitted the Merlin XX (and used appropriate boost, say 15lbs) then the FW 190s superiority would have been much less marked.
But the Merlin XX was needed for Hurricanes and bombers.

Schweik said:

And yet so many Merlins were being wasted on bad or flawed airframes.



True but P-51s were of very limited use until Merlin 60's were put on them, and Spitfires were knocked back a peg by Fw 190s as we all know for a crucial period in the beginning (or lets say, end of the beginning) of the war before it got the two stage Merlins, and that is actually one of the places where I think Whirlwind could have been very helpful.

I'd also call P-51 and Spitfire 'medium' sized fighters though Spit is closer to a small one than the P-51 is. Certainly both are small next to a Tempest or a P-47.

Click to expand...

I'm not sure what point you are trying to make with your comments about different Merlins. They were still Merlins and a direct result of the concentration of Rolls-Royce Derby on that engine and its development and the deletion the Exe, Peregrine and eventually Vulture.
It was quickly apparent after the beginning of the war that the improvement and development of the Merlin engine offered the most direct, economical and efficient (in terms of units produced) path to improved fighter performance. That's why it was done.

If the Spitfire is a 'medium' sized fighter how would you characterise a T/E fighter like the Whirlwind? The Whirlwind had a wingspan about eight feet bigger than the Spitfire and nearly five feet bigger than a P-47.

The Spitfire, like the Bf 109, was the product of pre-war thinking that attempted to bolt the most powerful engine available onto the smallest practical airframe.

Schweik said:

Well, that's what I would assume anyway in a wartime situation. Some suggestion in here that RR could do as they pleased.

Click to expand...

No, during the war, the government was their sole customer. Profits were defined by HMG too.

Personally I tend to ignore wing span and go for wing area and weight when judging fighter "size". putting fighters into different size groups due to different aspect ratios seems to need too many exceptions and explanations.

Using "my" rule the Whirlwind and the Typhoon wind up being close equivalents. The Whirlwind actually had less wing area than a Hurricane.

It also helps planes like the P-38 (52ft wing span) avoid being compared to bombers

Kevin J said:

No, during the war, the government was their sole customer. Profits were defined by HMG too.

Click to expand...

It was rather more complicated than that.

If I have time I will try and write something on this which doesn't expand into a book!

Edit:
A very brief overview, lifted verbatim from 'Industry and Air Power - The Expansion of British Aircraft Production, 1935-1941' by Sebastian Ritchie.

'During the aircraft boom of the mid 1930s the nominal value of publicly issued capital in the aircraft industry increased from £3.7 million to more than £19 million, but as production began to outstrip the industry's own financial capacity the state's role in providing capital inevitably increased. Very large numbers of aircraft were built under agency agreements after 1938 but the government preferred to maintain operations on a commercial basis wherever possible, and state capital assistance schemes and bank lending provisions were therefore liberalised. When it became clear that the firms were also employing excess profits to finance production the government turned a blind eye. Yet this did not mean underwriting exorbitant production expenses. The pricing mechanism thrashed out between state and industry during the rearmament years rewarded firms for the improvements of efficiency which the government was so anxious to achieve and imposed effective long term controls over aircraft costs.'

RR could not do as they pleased during the war but they could certainly recommend certain paths or write up reports that steered the conversations the way RR wanted them to go.

Many companies could slow down work (redirect/reallocate resources) to other projects rather than keep working full bore on a project the company thought was a loser. Some work has to keep going to avoid being in default of contract.

RR claims that every Peregrine is going to cost two Merlin's as far as production output goes. This could very well be true if you count all dead time on the machines for change over from Merlin to Peregrine parts against the Peregrine. Of course this depends on how often you change over the machinery. Run off enough parts for 60 engines and then swap back to Merlin parts or only make 20 sets of Peregrine parts and swap tooling 3 times as often? a lot more time when nothing is being made and if you can blame it on the Peregrine it is easier to kill the Peregrine program.

People also have to aware of the fuel situation which allowed certain engines (not all) to make much more power in just a few years than was thought possible. Please remember that the RR Vulture, the Sabre and the Centaurus were all started when 87 octane was fairly new, 100 octane (and that is 100/100) was know about but introduction was uncertain and such things as 100/130 let alone anything higher was science fiction. If you wanted big power you needed big (really big) engines and thus you needed big airplanes to carry them.
As they realized the improved fuel would allow higher power from smaller, existing engines the need for larger or strange engines (in RR's case the Vulture or the Exe or Cressy) diminished considerably.

Shortround6 said:

...
Part of the Problem the Spits had with the FW 190 is that no first line Spitfire fighter ever had a single stage two speed supercharger. Had they fitted the Merlin XX (and used appropriate boost, say 15lbs) then the FW 190s superiority would have been much less marked.
But the Merlin XX was needed for Hurricanes and bombers.

Click to expand...

What kind of advantage the Merlin XX offers vs. Merlin 45 once we're above 12000 ft?

Shortround6 said:

It might be better to say that the Peregrine, while it had potential for development, had no real market for sales. What was the market for a developed 1000-1100hp Peregrine when you take an off the shelf 1000-1100hp Merlin for just a bit more size and weight? And the Merlin might last longer between overhauls being lower stressed.
omissis

Click to expand...

Yes, exactly.
What I wanted to say is that Peregrine was way too small for the airframes that were going to war, even squeezed to the limit... so, no practical reason reason to spend resources squeezing it. The "Market", as you rightly said, wanted different power outputs.