# Westland Whirlwind alternative engines?



## gjs238 (Mar 23, 2012)

In lieu of the Rolls-Royce Peregrine

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## Shortround6 (Mar 23, 2012)

None really. 

Just get somebody behind the program and go. Some of the cooling problems could have been solved with better training in the beginning and/or a different radiator flap setting/arrangement.

The Taurus didn't work out all that well and didn't offer as good as performance at altitude as the Peregrine did. The 9 cylinder radials have too much drag and bigger engines (Merlin, Hercules, R-1830) require so much redesign it is hard to say what the resulting performance would be.


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## yulzari (Mar 23, 2012)

gis238, a search of old threads will show consideration of Taurus, Mercury, Merlin, Dagger and Allisons as possible alternatives. 

The intended Peregrine upgrade would have given have given a considerable step forward (up to 1,100 bhp from memory) but Rolls Royce decided to concentrate on Merlin development (yet somehow managed to do the Exe, Crecy, Eagle etc.). 

My own take is for Westland to upgrade the systems on the existing airframe and replace the Peregrines with engines in current production and not vital elsewhere: Dagger for air defence and ground level rated Mercuries for ground attack with my preference for 2 S-type 40mm cannon with HE rounds (not for tank killing but for accurate fire upon softer skin targets.)

Westlands wanted to fit Merlins which was quite feasible.


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## Shortround6 (Mar 23, 2012)

I am afraid the Dagger is a no go for air defense. While more powerful down low than the Peregrine ( and that is with the Peregrine using 87 octane) by the time you get to 15,000ft they have about the same power. The Dagger has more drag and even more cooling problems than the Peregrine. 

The Mercury has even more drag and without 100 octane fuel little hope of coming close to the Peregrines performance. 

If you want 40mm guns just stick them under a Blenheim and have at it. (or a Boston/Havoc, Baltimore, etc).

I like the Whirlwind and think it is a shame that it didn't get more support and a perhaps a newer Peregrine engine. A Merlin XX equivalent or even a Merlin 45/46 equivalent.


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## davebender (Mar 23, 2012)

Dr. Tank used DB601 engines for the Fw-187. British aircraft designers should be capable of the same thing with the Westland Whirlwind and Merlin engine.

Why settle for anything less?


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## tomo pauk (Mar 23, 2012)

Fw-187 was a bigger airframe (wing area 1/3rd bigger vs. Whirly), so DB-600 series there seem like a good fit. Westland just made their bets on a wrong horse (Peregrine) and tailored the plane accordingly. The plane was simply to small. Whirlwind modified to take a single Merlin sounds nice to me 
Gloster F.9/37 would've been far better platform for Merlin.


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## Shortround6 (Mar 23, 2012)

Mainly because the Whirlwind was a much smaller airframe than the FW 187.

It had a smaller wing than a Hurricane or F4F and a P-51D was about 10% lighter take-off in clean condition. 

Westland offered a "version" with twin Merlin's but one has to wonder how much of the original airframe would have been left. Look at the several projects to "improve" the 109 that were canceled when only 30-40% of the 109 airframe was left.


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## Edgar Brooks (Mar 23, 2012)

yulzari said:


> The intended Peregrine upgrade would have given have given a considerable step forward (up to 1,100 bhp from memory) but Rolls Royce decided to concentrate on Merlin development (yet somehow managed to do the Exe, Crecy, Eagle etc.)..


Not quite true; Rolls-Royce reckoned that upgrading, from 87 to 100 octane, would essentially mean starting from scratch with a new engine. Only one Exe was built, and used in a test airframe; it was successful, and a larger version, the Pennine, was designed, but abandoned at the end of the war. The Crecy never worked properly, being beset by vibration problems. The Eagle was rejected by aircraft manufacturers since its layout meant that pilots couldn't see over the top of it. 


> Westlands wanted to fit Merlins which was quite feasible


No, they didn't, and it wasn't feasible, as Westland admitted to the Air Ministry; the airframe could not take bigger engines, and was not strong enough, either (and this is Westland saying this, so please go up in the air about it.)
Add all of this to Westland being capable of building no more than 1 or 2 per week, and the Spitfire Vc, which could also carry 4 cannon, was imminent, and only needed one engine, and the decision is easy to understand.


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## Shortround6 (Mar 23, 2012)

The thing was that Supermarine couldn't build more than a few Spitires a week in 1938 either and the production was farmed out to other factories. Westland was also building lysanders and apparently nobody made the dicision to make the Lysander lower in priority. Granted this might have meant 3-4 Whirlwinds per week 

I am not sure why the Peregrine would have to start over again to use 100 octane fuel as no other engine had to do that. Granted some got more benefit than others but if the Bristol Mercury and Pegasus could be made to use 100 octane with modest power gains ( my books are not with me but around 10%...?)it should have worked in the Peregrine. Going to 12lbs boost should not have been that big a deal. 15lbs might have been within reach. Going higher would present more problems just as it did for the Merlin and the effort was not worth it.


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## wuzak (Mar 23, 2012)

yulzari said:


> The intended Peregrine upgrade would have given have given a considerable step forward (up to 1,100 bhp from memory) but Rolls Royce decided to concentrate on Merlin development (yet somehow managed to do the Exe, Crecy, Eagle etc.).





Edgar Brooks said:


> Not quite true; Rolls-Royce reckoned that upgrading, from 87 to 100 octane, would essentially mean starting from scratch with a new engine. Only one Exe was built, and used in a test airframe; it was successful, and a larger version, the Pennine, was designed, but abandoned at the end of the war. The Crecy never worked properly, being beset by vibration problems. The Eagle was rejected by aircraft manufacturers since its layout meant that pilots couldn't see over the top of it.



The Exe, Peregrine, Vulture and Griffon development programs were suspended for a period of time during 1940 - about the time of BoB - to concentrate on Merlins, which were desperately needed for types in service - iw the Spitfire and Hurricane. Not sure about the Crecy program.

After the BoB the programs were restarted, but Rolls-Royce asked the MAP to cancel all but the Merlin and Griffon. This the MAP agreed to, cancelling the Exe, Peregrine and Vulture. The Crecy was to continue mainly as a research project and received only small amounts of resources. The problems with the Crecy were many, but I'm not sure vibrations were one of them. Melting pistons certainly was.

The Rolls-Royce Pennine was a late war project for the post war civilian market. It first ran in 1945, so it had no effect on the development of the Merlin in the early war years.

The Rolls-Royce Eagle 22 was also a relatively late project, first running in 1944. It was to power the next generation of Hawker and Supermarine single engine fighters - proposals suggesting max speeds over 500mph. 

The Eagle wasn't rejected by manufacturers because "pilots couldn't see over the top of it". The Eagle would pose no more problem for visability than any of the big radials - being 50" high x 43.4" wide, compared to a Centaurus at 56" in diameter. The Westland Wyvery prototype used the Eagle, with a raised canopy negating any problems with visibility.

The Pennine and Eagle were both dropped by Rolls-Royce as they had realised the future in both militry and civil aviation was the gas turbine - jets and turboprops. The Wyvern's Eagle was replaced in production versions with a turboprop - the Armstrong Siddeley Python.


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## Edgar Brooks (Mar 23, 2012)

Shortround6 said:


> The thing was that Supermarine couldn't build more than a few Spitires a week in 1938 either and the production was farmed out to other factories. .


We weren't at war in 1938, and work wasn't "farmed out." Another factory was purpose-built, in anticipation of greater need, but did not begin production until mid-1940; Westland began building Spitfires in 1941, when countering the 109F was seen as the priority (together with the coming need for Seafires,) and, since it was capable of high performance well above 20,000', the Whirlwind would never have been able to cope.


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## davebender (Mar 23, 2012)

If the RAF specification requires RR Merlin engines that will not happen.


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## Edgar Brooks (Mar 23, 2012)

wuzak said:


> The Crecy was to continue mainly as a research project and received only small amounts of resources. The problems with the Crecy were many, but I'm not sure vibrations were one of them. Melting pistons certainly was...


Perhaps I may be allowed to quote A.A.Rubbra, Rolls-Royce's designer Technical Director,"One item I recall was the high torsional vibration stresses in the supercharger drive, to overcome which a freewheel device was tried. Other serious problems were main engine vibration, piston and sleeve cooling, all contributing to a complicated design."


> The Eagle wasn't rejected by manufacturers because "pilots couldn't see over the top of it". The Eagle would pose no more problem for visability than any of the big radials - being 50" high x 43.4" wide, compared to a Centaurus at 56" in diameter. The Westland Wyvery prototype used the Eagle, with a raised canopy negating any problems with visibility


So I simplified it; Rubbra again,"Although the Eagle eventually performed quite well on the test bed when fitted with its intended supercharger and carburettor, its reception by the aircraft industry was not enthusiastic mainly because of the effect on the pilot's view when installed in the typical single engine fighter of the day. This eventually led to its abandonment in favour of the "F,"* although not before a larger version known as the Eagle XX was worked on at West Wittering but finally abandoned."
With regard to the Wyvern, I thought that this site concentrates on WWII?
* = Kestrel


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## yulzari (Mar 23, 2012)

Shortround6. In putting 40mm cannon on Blenheims you might want to consider that this is a far larger and heavier airframe than a Whirlwind with a far worse performance and uses the Mercury engines you condemn as high drag and low power. 

A ground level rated Mercury has nearly as much power as a Peregrine and needs no radiator and coolant. The Dagger can match Peregrine installed weight, in 100 octane optimised form meets 100 octane Peregrine power and with a regeared supercharger can (as with any single speed supercharged engine) match any desired height power optimum. It's cooling never prevented it being used in Hectors even when dragging Hotspur gliders around. Most important of all, it was a production engine that was actually available at the time, as was the Mercury. I will agree that the Dagger was a bugger to service and needed the pilot to carefully read and comply with the pilot notes. Most other suggestions for Peregrine replacements were not actually available to slot in on a production basis. Aircooled engines also allow the inner wing radiators to be removed leaving space for further fuel tanks and therefore range.


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## wuzak (Mar 23, 2012)

Edgar Brooks said:


> So I simplified it; Rubbra again,"Although the Eagle eventually performed quite well on the test bed when fitted with its intended supercharger and carburettor, its reception by the aircraft industry was not enthusiastic mainly because of the effect on the pilot's view when installed in the typical single engine fighter of the day. This eventually led to its abandonment in favour of the "F,"* although not before a larger version known as the Eagle XX was worked on at West Wittering but finally abandoned."
> With regard to the Wyvern, I thought that this site concentrates on WWII?
> * = Kestrel



You are referring to the Eagle XVI X16 of the mid 1920s. I'm sure that Yulzari was referring to the Eagle 22 H-24 sleeve valve engine of 1944. 

Still, the Eagle XVI was wider than the F/Kestrel, not sure if it was any deeper.

The Wyvern specification and development began in WW2, to specification N11/44.


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## Edgar Brooks (Mar 23, 2012)

davebender said:


> If the RAF specification requires RR Merlin engines that will not happen.


The RAF didn't issue specifications; that was done by the government department (Air Ministry during the war.) The RAF (as always) had to make do with what they were given.
A spec normally never set the engine, either, it was left to the company to come up with a viable design, with the engine of their choice. For the "Whirlwind" spec, Bristol's Type 153 153A used a Hercules, Hawker tendered a Hurricane with 4 Oerlikons, and Supermarine went with a Spitfire, also with 4 Oerlikons. Boulton Paul and Fairey also tendered, but the details aren't known.


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## wuzak (Mar 23, 2012)

yulzari said:


> Shortround6. In putting 40mm cannon on Blenheims you might want to consider that this is a far larger and heavier airframe than a Whirlwind with a far worse performance and uses the Mercury engines you condemn as high drag and low power.
> 
> A ground level rated Mercury has nearly as much power as a Peregrine and needs no radiator and coolant. The Dagger can match Peregrine installed weight, in 100 octane optimised form meets 100 octane Peregrine power and with a regeared supercharger can (as with any single speed supercharged engine) match any desired height power optimum. It's cooling never prevented it being used in Hectors even when dragging Hotspur gliders around. Most important of all, it was a production engine that was actually available at the time, as was the Mercury. I will agree that the Dagger was a bugger to service and needed the pilot to carefully read and comply with the pilot notes. Most other suggestions for Peregrine replacements were not actually available to slot in on a production basis. Aircooled engines also allow the inner wing radiators to be removed leaving space for further fuel tanks and therefore range.



Many Herefords were re-engined with the Bristol Pegasus to become Hampdens again. One complaint was the extremely loud, high pitched exhaust noise which would surely become tiresome with one either side of you?

Why would the 100 octane Dagger match a 100 octane Peregrine since it didn't when running 87 octane?


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## Shortround6 (Mar 23, 2012)

As far as the Dagger goes, there were TWO versions in use. the one in the Hector was the IIIM which was rated at 700hp for take-off at 3500rpm with +3.5lbs boost and a max power of 825hp at 4000rpm +2.25lbs boost at 4000ft and the Dagger VIII which was rated at 955hp for take off at 4200rpm +6lbs boost and a max rating of 1000hp at 420rpm +6lb boost at 8750ft. the MK VIII was the one used in the Herefords. While the lower powered IIIMs may have given satisfactory service I have never seen anything good about the VIII. Obviously the MK VIII has a much greater heat rejection problem. Changes were made but apparently not enough. 

while you can change gears on a single speed supercharger to "help" get the performance desired it is by no means a change the gear and get "what ever" you want. Put a gear into the Dagger that gives better performance at 15,000ft and and the supercharger will take more power to drive at all altitudes, reducing power to the propeller. The faster turning impeller will heat the air more making for a less dense charge which will further cut the power and the heated air will limit the total amount of boost that can be used limiting low altitude performance even more.


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## yulzari (Mar 24, 2012)

Indeed altering the gearing to a single stage centrifugal supercharger is not as simple as choosing a gear for your desired power height in any engine. In the case of the Merlin Rolls Royce cropped the impeller on the MkV Spitfire to reduce exactly the situation you refer to. It is always a compromise (hence Rolls Royce 2 and 3 speed superchargers). What you have to do is choose what compromise meets your needs best. For air defence you need to be at peak above your bomber targets. For ground attack the peak needs to be at he height you will fight at if enemy fighters attack you.

I used to have a neighbour who worked for De Havilland on the air cooled engine side. He told me they were asked by the Air Ministry to comment on the Dagger installations. He said that De Havilland's comment was that there was adequate air intake capacity but any larger intake would have little effect as there was insufficient exit capacity. De Havilland had learned of the importance of this from their reverse flow experience with the big air cooled engines. He thought there were minor improvements to be made in the internal baffling but essentially all it needed was lower pressure at the exit. Remember the Peregrine and the IIIM Dagger wee not so far apart and the 100 octane Peregrine was not so far ahead of the VIII Dagger on 87 octane. If you go for the larger heavier alternatives you are sucked into a growing size and weight until you have a heavy fighter bomber (eg Mosquito). I would have preferred the Peregrine development to be continued in the existing airframe (yes the fuel and radiators could be improved) from the 1650 bhp original 1940 through the 2,200 bhp 1942 version and an ultimate Peregrine 2,500+ bhp 1944. However, the death of the Peregrine was part of the death of the double peregrine Vulture. To be fair to the decision makers, concentrating on the Merlin allowed worn out one to be used as raw material for Meteor tank engines when production of new Meteor parts were falling behind.

Totally OOT; the Irish put a Seafire engine into one of their Churchill tanks, complete with blower, to replace the 360 bhp Bedford flat12. Allegedly it allowed it to climb any slope where the tracks could grip and could maintain almost flat out speed across all terrain. God knows how long the transmission could have lasted but who would have thought that a Merlin could be impressive by reaching 20+mph!


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## nuuumannn (Mar 24, 2012)

> Boulton Paul and Fairey also tendered, but the details aren't known.



Boulton Paul tendered two versions of the P.88 to F.37/35 to which the Whirlwind was built. The P.88s were to be powered by either a Bristol Herc HE.1.SM (P.88A) or a RR Vulture (P.88B) Both had 2 X 20 mm cannon in each wing. A contract for two aeroplanes was placed in December 1936, but was cancelled in January 1937. The Vulture engined variant looked like a Defiant without a turret, but the Herc engined one was quite different in appearance. Only five companies submitted designs to to F.37/35; BP P.88 x 2, Bristol also two designs, Hawker, Supermarine (two designs, the Supermarine 312 and twin engined 313) and Westland. Fairey did not; however, they did to F.6/39, about which no details are known. This spec produced the Vickers 432.


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## wuzak (Mar 24, 2012)

yulzari said:


> However, the death of the Peregrine was part of the death of the double peregrine Vulture. To be fair to the decision makers, concentrating on the Merlin allowed worn out one to be used as raw material for Meteor tank engines when production of new Meteor parts were falling behind.



The Vulture was not a double Peregrine, and both were cancelled at the same time for the same reasons - not enough resources and only one type in production using each of them. 

The failings of the Vulture were not the same as the failings of the Peregrine. If they shared any components it was probably only the pistons, maybe the valves and valve springs and possibly the valve rocker arms. The Bore spacings were different (6.1"for the Vulture, 5.625" for the Kestrel/Peregrine), so the blocks were different. The main problems for the Vulture were due to its X-layout and the master and slave rod arrangement - things thathad no effect on the Peregrine.


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## Shortround6 (Mar 25, 2012)

I still don't what the failings of the Peregrine were?

Keeping 2 squadrons in combat use 3 years after the engine went out of production doesn't sound like that bad of an engine. If it had been really troublesome you would think the effort of keeping it in service wasn't worth the results.


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## wuzak (Mar 25, 2012)

Shortround6 said:


> I still don't what the failings of the Peregrine were?



I think they were having similar coolant sealing problems that plagued the single block/head Merlins until they were replaced by a two piece design.


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## Edgar Brooks (Mar 25, 2012)

Shortround6 said:


> I still don't what the failings of the Peregrine were?.


Mostly it was its lack of performance at heights above 20,000'; it fell off, and, above 27,000' was considered quite poor, so much so that, even though it might, under favourable conditions, reach 30,000', the rate of climb over the last 4-5,000' dropped to 500' per minute.
With the 109F already regularly coming over above 22,000', the Whirlwind was viewed as verging on obsolescence, even before the end of 1940.
As early as May, 1940, Bulman said that the Peregrine was built in Derby, and could not be diverted to Crewe or Glasgow; Derby were also building the Vulture, Merlin X, Merlin XX, and the Griffon, and the Peregrine could only be continued at the detriment of those, with each engine costing two Merlins, or by postponing the Griffon, which was due to start in July, 1941.
It was also felt that uprating it to take 100 octane would basically require a new Mark of Peregrine.
It was the conversion to bomb-carrying that kept the Whirlwind in service for so long, but it was pointed out that the Hurricane, using only one engine, carried 50% more cannon ammunition for the same number of guns, and used a readily-available engine, which was also used by other aircraft, while the Peregrine had no other applications. 
The Whirlwind also used 50% more materials to perform (fighting) tasks less well than the Spitfire; add in the impending arrival of the Typhoon, which, in 1941, was the great hope for the future, and the Whirlwind had no chance.
70 years on, it's easy to let hearts rule heads, but not when a nation is fighting for its very existence alone (apart from the considerable input from the Commonwealth, and escapees from occupied Europe, of course.)


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## Shortround6 (Mar 25, 2012)

The lack of altitude performance was a supercharger problem and one it shared with most other engines of it's time period. Critical altitude of the engine being 1,250ft less than the Merlin III. The Whirlwind as an aircraft was not going to give the altitude performance of the Spitfire using engines of equivalent supercharger performance because of weight and drag. It's altitude performance compared to the Hurricane might be much closer, using superchargers of equivalent supercharger performance. 

The Whirlwinds problems are that it got behind in timing and apparently, nobody had the faith in it to push it through in 1938-39-very early 1940. The same rather applies to the Peregrine engines. There is no reason that a Peregrine, if made on equivalent tooling should take as much effort to build as two Merlins. If it was being made in small batches (and it was or in a trickle) without proper jigs and fixtures/tooling that the Merlin had, then I see no reason not to believe that it took much more time/effort to build one Peregrine, but that is not a fault of the basic engine design.
TO use 100 octane to it's fullest extent would certainly require a new mark but then the Merlin went through many marks too, in order to fully use the new fuel/s. 

There are at least 3 sources I have found that mention 100 octane fuel in the Peregrine. Unfortunately Lumsden's book, while giving boost levels and RPM for the Peregrine for both 87 and 100 octane fuel doesn't give most of the corresponding power outputs. It does give 880 hp for take off using 9lbs boost though and gives 9lbs boost as the limit at 3000rpm at altitude not given and power not given, also 9lbs boost at 2850rpm for climb or 1/2 hour rating. The 1945 edition of "Aircraft engines of the World" 765hp at 3000rpm at 43.7in (6.75lbs? boost). 960hp/3000rpm at 12,000ft, military and 860hp/2850rpm at 13,500ft. manifold pressure not given. These would seem to be consistent with 775hp rating for take off at 6/75lbs in other books and the 880hp at 15,000ft rating using 6-6.75lbs boost. 
Just like the Merlin III, there is no gain in performance at altitude to be had using 100 octane fuel without a new supercharger. But like the Merlin III, it appears that a new mark of engine was not needed in order to get some performance boost form 100 octane fuel. The Hurricane got a new supercharger in the fall of 1940 in order to try to keep in competitive as a fighter. The Spitfire had a new supercharger in service by the Spring of 1941.

The Hurricane carried 50% more ammo because the Whirlwind was never changed to belt feed guns. There were at least 2 if not 3 different four 20mm gun arrangements tried on Whirlwinds using belt feeds but none were approved for use (refit?) as the plane was either out of production or already canceled. The belt feed Whirlwinds carried approximately 33% more ammo than the Hurricane as well it should seeing as how it had several hundred more horsepower. 

In the long run stopping the Whirlwind and the Peregrine were the right things to do but there seems to be a bit of a smokescreen as to exactly why and when.


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## wuzak (Mar 25, 2012)

I think that, when it all comes down to it, Rolls-ROyce didn't feel they had the time or resources to develop the myriad engine designs it had at the start of the war. While the Peregrine's problems may have been solved relatively quickly the thought may have been that it was of limited usefulness as the Merlin was available and already been used in many types. Then there was the push to increase the performance of the Merlin - how much would that have been affected if there was aparallel program on the Peregrine as well as the Griffon? Or would the Griffon program have suffered?

On the supercharger issue, I wonder if the Peregrine could have used the Merlin 61 supercharger - or would it be too big?

I would think an rpm increase would be necessary - the Vulture was designed for 3200rpm, though the Peregrine, with the same stroke, had a maximum of 3000rpm.


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## Edgar Brooks (Mar 26, 2012)

Shortround6 said:


> The lack of altitude performance was a supercharger problem and one it shared with most other engines of it's time period. Critical altitude of the engine being 1,250ft less than the Merlin III. The Whirlwind as an aircraft was not going to give the altitude performance of the Spitfire using engines of equivalent supercharger performance because of weight and drag. It's altitude performance compared to the Hurricane might be much closer, using superchargers of equivalent supercharger performance..


But it wasn't altitude performance that was needed; Dowding said that he might be glad of all the Whirlwinds that he could get, because, in 1940, it was the only aircraft that had the firepower to deal with tanks, in the event of the expected invasion. He kept the Whirlwinds out of the BoB, for that reason, and because there were only a few serviceable airframes. When the threat of invasion receded, the Hurricane (which had been planned to end in May, 1941) was found to be capable, with the Merlin XX, of doing anything that the Whirlwind could do. 


> The Whirlwinds problems are that it got behind in timing and apparently, nobody had the faith in it to push it through in 1938-39-very early 1940.


 A lot of that was due to the then-held idea that twin engined fighters needed counter-rotating engines, which, at that time, meant totally different components (the Hornet made use of an extra gear, in the train, to achieve this post-war, but that wasn't feasible, then.) The prototype Whirlwind had this feature, but it was found to be a false premise, so was dropped, leaving R-R to produce just the single type of engine, but already delayed.


> There is no reason that a Peregrine, if made on equivalent tooling should take as much effort to build as two Merlins. If it was being made in small batches (and it was or in a trickle) without proper jigs and fixtures/tooling that the Merlin had, then I see no reason not to believe that it took much more time/effort to build one Peregrine, but that is not a fault of the basic engine design.


This is going to sound slightly rude, but isn't meant to; you're saying that, in 2012, you have a better idea of Rolls-Royce's capacity than the then-management, which is a fairly dangerous statement to make. R-R were already trying to get Ford to build their engines, and eventually needed Packard to build thousands of Merlins, starting with the 28 (a Packard version of the XX.)


> TO use 100 octane to it's fullest extent would certainly require a new mark but then the Merlin went through many marks too, in order to fully use the new fuel/s.


But the Merlin had many uses, while the Peregrine had only one, which was an obsolete airframe.


> There are at least 3 sources I have found that mention 100 octane fuel in the Peregrine. Unfortunately Lumsden's book, while giving boost levels and RPM for the Peregrine for both 87 and 100 octane fuel doesn't give most of the corresponding power outputs. It does give 880 hp for take off using 9lbs boost though and gives 9lbs boost as the limit at 3000rpm at altitude not given and power not given, also 9lbs boost at 2850rpm for climb or 1/2 hour rating. The 1945 edition of "Aircraft engines of the World" 765hp at 3000rpm at 43.7in (6.75lbs? boost). 960hp/3000rpm at 12,000ft, military and 860hp/2850rpm at 13,500ft. manifold pressure not given. These would seem to be consistent with 775hp rating for take off at 6/75lbs in other books and the 880hp at 15,000ft rating using 6-6.75lbs boost.


The Peregrine could use 100, at higher boost levels, but only in short bursts, measured in seconds, which damaged the engine. 


> In the long run stopping the Whirlwind and the Peregrine were the right things to do but there seems to be a bit of a smokescreen as to exactly why and when


These conspiracy theories are all very fine, but fall down on one fundamental point; Westland built just over 100 Whirlwinds, for which no use could be found after 1940 (until it was converted to carry bombs,) but built over 1600 Spitfires and Seafires, and were still invited to tender for (and build) other aircraft. This hardly sounds like an attempt to damage the company, which is what others have alleged. Times without number, I have to point out that files in our National Archives have a minimum closure time of 30 years, so anyone trying to find information, on the Whirlwind story, has had to wait until 1975+; the files are there, I've read them, and the decisions were taken quite openly, with no conspiracies involved.


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## wuzak (Mar 26, 2012)

Edgar Brooks said:


> A lot of that was due to the then-held idea that twin engined fighters needed counter-rotating engines, which, at that time, meant totally different components (the Hornet made use of an extra gear, in the train, to achieve this post-war, but that wasn't feasible, then.)



Why wasn't it feasible then? It was just an idler gear between the two that were alreay there. Surely not beyond Rolls-Royce's ability?

Was it a widely held belief? What other twins were designed with this in mind? Certainly no radial twins had counter-rotating props.




Edgar Brooks said:


> The prototype Whirlwind had this feature, but it was found to be a false premise, so was dropped, leaving R-R to produce just the single type of engine, but already delayed.



So, how was the counter-rotating props achieved? Reversing the engine?

My thought is that the Whirlwind was designed around two same rotating engines, but one was evaluated with counter-rotating props, which was found to make no difference to the pilots.


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## Edgar Brooks (Mar 26, 2012)

wuzak said:


> Or would the Griffon program have suffered?.


I already noted that R-R said that the programme would probably have to be delayed.


> On the supercharger issue, I wonder if the Peregrine could have used the Merlin 61 supercharger - or would it be too big?


The Peregrine had a downdraft carburettor intake, and the 61's blower needed an intercooler, and thus extra radiators, not easy in a small airframe.


> I would think an rpm increase would be necessary - the Vulture was designed for 3200rpm, though the Peregrine, with the same stroke, had a maximum of 3000rpm


The Merlin was limited to 3000 rpm, so it's doubtful that would have been possible by any more than a very small %age.


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## Edgar Brooks (Mar 26, 2012)

wuzak said:


> Why wasn't it feasible then? It was just an idler gear between the two that were alreay there. Surely not beyond Rolls-Royce's ability?
> Was it a widely held belief? What other twins were designed with this in mind? Certainly no radial twins had counter-rotating props..


You're using 20:20 hindsight, again. R-R, in 1935, thought it necessary; for their reasons, you'll need to ask Rolls-Royce Heritage Trust. According to the Air Ministry, it was a French theory, prevalent at the time. The Hornet's Merlins used an idler gear, the Peregrines didn't; they were built as "handed" engines, for reasons known to R-R, but not me.


> So, how was the counter-rotating props achieved? Reversing the engine?


I've no idea; "handed" doesn't really give us the definitive answer, but I would suspect reversing was the answer.


> My thought is that the Whirlwind was designed around two same rotating engines, but one was evaluated with counter-rotating props, which was found to make no difference to the pilots


It was the other way round (pardon the pun); the prototype had handed engines, while the second prototype didn't, and it was then that it was found to make no difference.


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## wuzak (Mar 26, 2012)

Edgar Brooks said:


> I've no idea; "handed" doesn't really give us the definitive answer, but I would suspect reversing was the answer.



Even if the engine was "reversed" Rolls-Royce would still have needed to make at least one extra idler gear - because it was unlikely that they would go to the trouble of making opposite hand superchargers, magnetos, etc.

Left handed V-1710s have the crank rotate in the opposite direction to right handed engines, but the supercharger stil rotates in the same direction.


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## Edgar Brooks (Mar 27, 2012)

wuzak said:


> Even if the engine was "reversed" Rolls-Royce would still have needed to make at least one extra idler gear - because it was unlikely that they would go to the trouble of making opposite hand superchargers, magnetos, etc..


Rolls-Royce's chief designer doesn't agree with you, and I quote,""For this installation it was decided to hand all the engine components necessary to provide reverse rotation. This was a considerable complication and was abandoned on future engines. This experience led to the use of a special reduction gear for the Merlin engines used in the de Havilland Hornet aircraft in which an idler gear was introduced to obtain reverse rotation of the propeller, leaving other engine components unaltered."


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## wuzak (Mar 27, 2012)

Edgar Brooks said:


> Rolls-Royce's chief designer doesn't agree with you, and I quote,""For this installation it was decided to hand all the engine components necessary to provide reverse rotation. This was a considerable complication and was abandoned on future engines. This experience led to the use of a special reduction gear for the Merlin engines used in the de Havilland Hornet aircraft in which an idler gear was introduced to obtain reverse rotation of the propeller, leaving other engine components unaltered."



Jeez, they must have had plenty of time on their hands at the time....


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## Edgar Brooks (Mar 27, 2012)

wuzak said:


> Jeez, they must have had plenty of time on their hands at the time....


Plans tenders were made in 1936, with construction of the 1st. prototype started mid-1937, so there was no war on, and still hopes that it wouldn't happen.
Rolls-Royce, before they went bust around 1970, were a byword for perfectionism; we were told, during the 1950s, how a man, touring in Spain, had the back axle of his R-R (dont know the marque) break, so he contacted R-R, who flew two men out to Spain, with a spare axle, which they fitted, allowing the tour to continue. When the man got home, he waited (and waited) for the bill, but received nothing. Eventually he contacted the company, direct, and asked about his bill, to be told,"Sir, Rolls-Royce cars do not break down."


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## Airframes (Mar 27, 2012)

Still true, to an extent, today. Last year (and not the first time seen), I saw a Roll Royce, obviously immobile, being loaded onto a curtain-sided recovery trailer, presumably to be taken to a garage for repair. Once loaded, the curtains were drawn, just as on a large articulated wagon, hiding the entire car from view. Obviously, Rolls Royce did not want one of their 'creations' being seen to have been recovered after breakdown - because Rolls Royce' "do not break down....".


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## Shortround6 (Mar 28, 2012)

Edgar Brooks said:


> But it wasn't altitude performance that was needed; Dowding said that he might be glad of all the Whirlwinds that he could get, because, in 1940, it was the only aircraft that had the firepower to deal with tanks, in the event of the expected invasion. He kept the Whirlwinds out of the BoB, for that reason, and because there were only a few serviceable airframes. When the threat of invasion receded, the Hurricane (which had been planned to end in May, 1941) was found to be capable, with the Merlin XX, of doing anything that the Whirlwind could do.



This is part of what I mean about a smoke screen, in your post #24 you talked about the lack of high altitude performance in the fall winter of 1940/41 and the Whirlwinds inability to combat the 109F at 22,000ft and above, no you are saying it was viewed as an anti-tank aircraft and altitude performance was needed just a few months before that. Which is it? 




Edgar Brooks said:


> This is going to sound slightly rude, but isn't meant to; you're saying that, in 2012, you have a better idea of Rolls-Royce's capacity than the then-management, which is a fairly dangerous statement to make. R-R were already trying to get Ford to build their engines, and eventually needed Packard to build thousands of Merlins, starting with the 28 (a Packard version of the XX.)



Actually, it sounds a lot rude. Perhaps I didn't say it well but I thought I tried to give an explantion as to _why_ a 1296cu in V-12 engine "cost" twice as much as a 1650cu in V-12 engine when both shared almost the same details (valves per cylinder, over head cams and so on) when it flies in the face of common sense. As an example, say R-R had two machines performing similar operations on connecting rods. One machine is making Merlin rods continuously. the other is making Peregrine rods and Merlin rods in alternating batches. Not only do you loose the production of Merlin rods while making the Peregrine rods but every time the machine is changed over (tool holders, part fixtures/clamps, etc) you loose production of the Merlin rods. Multiply that times the thousands of parts and some of the parts taking dozens of operations and I can understand that every Peregrine could cost the production of two Merlins, but it doesn't mean the Peregrine actual cost ( in money) twice what a Merlin did and it doesn't mean that the Peregrine was actually twice as hard as the Merlin to make. It does speak to the capacity of Rolls-Royce in manufacturing terms. 



Edgar Brooks said:


> But the Merlin had many uses, while the Peregrine had only one, which was an obsolete airframe.



The Whirlwinds airframe was obsolete when? In 1940? In 1941? 



Edgar Brooks said:


> The Peregrine could use 100, at higher boost levels, but only in short bursts, measured in seconds, which damaged the engine.



Care to give a source for this? In Victor Bingham's book on the Whirlwind he copies what I believe are the pilots notes and part of the take of procedure is to run each engine (one at a time) up to 2950/3000rpm and 9lbs of boost to check the supercharger boost limit. If the engine was damaged in in seconds doing this it seems it would be a very foolish thing to do before each and every flight? perhaps the procedure was changed at a later date? 



Edgar Brooks said:


> These conspiracy theories are all very fine, but fall down on one fundamental point; Westland built just over 100 Whirlwinds, for which no use could be found after 1940 (until it was converted to carry bombs,) but built over 1600 Spitfires and Seafires, and were still invited to tender for (and build) other aircraft. This hardly sounds like an attempt to damage the company, which is what others have alleged. Times without number, I have to point out that files in our National Archives have a minimum closure time of 30 years, so anyone trying to find information, on the Whirlwind story, has had to wait until 1975+; the files are there, I've read them, and the decisions were taken quite openly, with no conspiracies involved.



I don't think there was a conspiracy, more like a comedy of errors which some people then tried to sweep under the rug. Somebody must have thought the Whirlwind was good for something or they wouldn't have kept it around for as long as they did. Maybe it was the lack of a rear seat limiting it's ability to be turned into a target tug that kept in the front line so long  

The Bombs were not added until 1942 and then, as the story goes, at the instigation of the using squadron/s. In any case keeping 2 squadrons around for over a year before getting around to putting the bombs on them certainly doesn't sound like no use. 

As I said before, stopping the program was the right decision, it is just that too many of the excuses don't hold water.


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## wuzak (Mar 28, 2012)

Edgar Brooks said:


> The Peregrine had a downdraft carburettor intake, and the 61's blower needed an intercooler, and thus extra radiators, not easy in a small airframe.



I said nothing about the airframe. Just wondering if the Merlin 61 supercharger could have worked on the Peregrine. The 130/131s on the Hornet also had downdraft carbies, so that was certainly possible.

If RR were going to adapt the Merlin 61 supercharger to the Peregrine I dare say t is because they had more roles for it than just the Whirlwind.




Edgar Brooks said:


> The Merlin was limited to 3000 rpm, so it's doubtful that would have been possible by any more than a very small %age.



For the same piston speed as a Merlin at 3000rpm the Peregrine would get nearly 3300rpm (3275rpm in fact).

For an equivalent piston speed to a Griffon 65 the Peregrine would be at 3300rpm.


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## wuzak (Mar 28, 2012)

SR, at the end of the day the Peregrine was a victim of rationalisation. As was the Vulture and the Exe.


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## tomo pauk (Mar 28, 2012)

What benefits, if any, would be achieved by mating with Peregrine and superchargers from Merlin X, or XX? Something akin what was done for Merlin (from Vulture?) or for DB-605 (from 603)?


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## wuzak (Mar 28, 2012)

Ok, here's some numbers for a Peregrine to a hypothetical "RP.17SM" (equivalent to the Merlin's RM.17SM, and using that engine's performance as a basis fo the calculations).

There are three RM.17SM states I based the numbers on:
1. Max tested: 2620hp @ 3150rpm -> 2755kPa BMEP and 16.0m/s piston speed
2. Accidental sprint test: 2380hp @ 3300rpm -> 2389kPa and 16.76m/s.
3. RM.17SM rated power: 2200hp @ 3000rpm -> 2429kPa, 15.24m/s.

Considering the BMEPs with a 3000rpm limit for the Peregrine RP.17SM:
1. 1961hp
2. 1700hp
3. 1729hp

Considering the BMEPs and piston speed:
1: 2246hp @ 3436rpm
2: 2040hp @ 3600rpm
3: 1886hp @ 3273rpm

Of course had Rolls-Royce been developing the Merlin, the Griffon and the Peregrine it is unlikely that the Merlin woudl have got to the RM.17SM stage, let alone the Peregrine getting to "RP.17SM".


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## wuzak (Mar 28, 2012)

tomo pauk said:


> What benefits, if any, would be achieved by mating with Peregrine and superchargers from Merlin X, or XX? Something akin what was done for Merlin (from Vulture?) or for DB-605 (from 603)?



The Merlin superchargers have greater capacity....so would potentially give more power.

And, from the XX's supercharger on, you would get better efficiency.

The V-1710 was fitted with a Merlin 61 supercharger by Allison for a test - and they found it gave almost exactly the same power. Suggesting to me that the supercharger was a key determining factor in power output.


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## tomo pauk (Mar 28, 2012)

Thanks.
What kind of power levels could we expect from XX's supercharger mounted on Peregrine, theoretically?


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## Edgar Brooks (Mar 28, 2012)

Shortround6 said:


> This is part of what I mean about a smoke screen, in your post #24 you talked about the lack of high altitude performance in the fall winter of 1940/41 and the Whirlwinds inability to combat the 109F at 22,000ft and above, no you are saying it was viewed as an anti-tank aircraft and altitude performance was needed just a few months before that. Which is it? .


 Don't put words into my mouth, I said no such thing. For fighter v fighter Dowding was unimpressed, but was quite happy to have it for use against tanks; now, as far as I know, no German tanks were ever encountered at altitude.


> Actually, it sounds a lot rude.


Sorry about that, but neither you, nor I, know what R-R were capable of, in 1940, so implying that they were incompetent/lying is going a bit far. 


> It does speak to the capacity of Rolls-Royce in manufacturing terms.


Precisely what I said; they didn't have the capacity (and said so,) so something(s) had to go. 


> The Whirlwinds airframe was obsolete when? In 1940? In 1941?


I said obsolescent, which is not the same thing.


> Care to give a source for this? In Victor Bingham's book on the Whirlwind he copies what I believe are the pilots notes and part of the take of procedure is to run each engine (one at a time) up to 2950/3000rpm and 9lbs of boost to check the supercharger boost limit. If the engine was damaged in in seconds doing this it seems it would be a very foolish thing to do before each and every flight? perhaps the procedure was changed at a later date?


In an inter-departmental note, an Air Ministry mandarin states,".....while the Peregrine is being cleared for 12 (not 9) lb boost and 100 octane fuel for emergency use, the development of the engine for full 100 octane rating is quite a different business, and would take a considerable time."
Emergency use in a Merlin was always seen as a last resort, and the amount of time had to be carefully registered; I see no reason why the Peregrine should have been treated any differently.


> I don't think there was a conspiracy, more like a comedy of errors which some people then tried to sweep under the rug.


And your evidence for this is..........? 


> The Bombs were not added until 1942 and then, as the story goes, at the instigation of the using squadron/s.


 AOC-in-C Fighter Command, in fact.


> In any case keeping 2 squadrons around for over a year before getting around to putting the bombs on them certainly doesn't sound like no use.


One squadron, actually, since 137 Squadron didn't exist, as a Whirlwind squadron, before 20-9-41, and flew its first operation 20-11-41.


> As I said before, stopping the program was the right decision, it is just that too many of the excuses don't hold water


Excuses? I didn't realise that a national government needed excuses; as far as I'm aware they made decisions based on the facts given to them by the companies involved.


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## Edgar Brooks (Mar 28, 2012)

wuzak said:


> I said nothing about the airframe. Just wondering if the Merlin 61 supercharger could have worked on the Peregrine. .


Since this thread concerns the Whirlwind, I rather assumed that the theory would be applied to that airframe.


> If RR were going to adapt the Merlin 61 supercharger to the Peregrine I dare say t is because they had more roles for it than just the Whirlwind.


Which brings us back to the point that R-R had no such plans.


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## Shortround6 (Mar 30, 2012)

Edgar Brooks said:


> Don't put words into my mouth, I said no such thing. For fighter v fighter Dowding was unimpressed, but was quite happy to have it for use against tanks; now, as far as I know, no German tanks were ever encountered at altitude.



Lets try to straighten out a few things. Dowding may have been unimpressed with it's fighter v fighter capability but wasn't he just as happy to have it in order to attack bombers as they became less vulnerable to rifle caliber machine guns as he was to have to attack tanks with? Letter from July 1st 1940. 
He is supposed to have thought it was a extravagant design as it use two engines to lift 4 cannon whereas the "new" Hawker fighter would lift six cannon using one engine. Of course the "new" Hawker fighter (Typhoon/Tornado) use a single 24 cylinder engine instead of two 12s and never got six cannon. I know you can't build two 12s for the "cost" of one 24, especially installed but the actually difference is not the 2 to 1 that is implied. 
The Whirlwind did suffer at the higher altitudes but then so did the Hurricane. Just not as bad. That is why the Hurricane got the Merlin XX engines. An attempt to extend it's useful life as a fighter aircraft. 



Edgar Brooks said:


> Sorry about that, but neither you, nor I, know what R-R were capable of, in 1940, so implying that they were incompetent/lying is going a bit far.



Talk about putting words in someone's mouth. I have tried (twice) to offer an explanation as to *WHY* Rolls-Royce may have felt that one Peregrine would produced would equal the loss of two Merlins and you say that I am implying that they were incompetent/lying.
It is simple manufacturing, building in small lots or building different parts on the same machinery in alternating time periods (days or weeks) is not as efficient as a constant production run. There is no incompetence about it. Unless you consider some the American companies to be incompetent. Not only did they not set up factories to build R-1830s at the same time as R-2800s but even the single stage R-2800s were built in a different "shadow" factory than the two stage R-2800s. 

The word "cost" can have a number of different meanings. Cost in money, cost in man hours, cost in materials, cost in production effort. Even the "cost" of certain production procedures changes with the number of parts in a production run or production rate. Machining parts from the solid can be cheaper than either castings or forgings if the production run is small enough that the cost of the molds or forging dies would out weigh the extra machine time. Specialized fixtures/jigs can speed up production and cut scrap, but are expensive to design and build and are only worth it if the production run is sizable. 



Edgar Brooks said:


> I said obsolescent, which is not the same thing.



From your post #27:
"But the Merlin had many uses, while the Peregrine had only one, which was an obsolete airframe."


Edgar Brooks said:


> In an inter-departmental note, an Air Ministry mandarin states,".....while the Peregrine is being cleared for 12 (not 9) lb boost and 100 octane fuel for emergency use, the development of the engine for full 100 octane rating is quite a different business, and would take a considerable time."
> Emergency use in a Merlin was always seen as a last resort, and the amount of time had to be carefully registered; I see no reason why the Peregrine should have been treated any differently.



AH, I see, not a directive, user note or anything connected with Rolls-Royce but an opinion from an "Air Ministry mandarin".

That explains it all. Just like the rumour that said it took 2 hours to change a wheel on the Whirlwind ( under 33 minutes by test at the A&AEE) or the high ranking officer that claimed it took two weeks to change an engine (35.4 man hours by test).

I also see no reason that the Peregrine should be treated any differently using _either_ 9lbs or 12 lbs of boost but that is a far cry from damaging the engine in seconds. Most ,if not all performance figures are with 6lbs of boost, 9lbs seems to have been OKed sometime in 1941, quite possibly with the same restrictions the Merlin had at 12lbs boost. But it seems to me, looking at this passage that the Peregrine may have already been cleared for 9lbs and this is a clearance for 12lbs in emergencies. Which is what ALL 12lb boost useage was during the BoB, correct? 

Now, for all I know the experiment failed and the 12lb boost was never approved for the Peregrine but don't tell me that 9lbs would wreck the engine in seconds. 

I would also like to know _when_ this Manderin made this pronouncement and what the status of the Merlin was in regards to boost pressures at the same time. 


Edgar Brooks said:


> And your evidence for this is..........?



the comedy of errors or the sweeping under the rug?

Comedy of errors.

Fluctuating initial requirements. 

Production contract delayed until test fights done while other war winning aircraft (like the Blackburn Botha) were ordered off the drawing board. 

Westlands own failures to get work done in a timely manner, subcontractors failure to supply parts in a timely manner. 

Time taken to adjust requirements to modern conditions. Like relaxing the requirement for 35lb tire pressure up to 42lbs which might mean more wheel ruts in the grass airfields but saved redesigning the the landing gear and rear of the nacelles. 

The Failure of the MAP to get a second source on line or even to instruct Westland as to which aircraft had priority in the Westland factory, the Lysander or the Whirlwind. of course if R-R wasn't going to provide the engines in a timely fashion there wasn't much sense speeding up airframe production. 

It goes on.... and on..... and on.

Sweeping under the rug???

Who was going to admit they canceled the Peregrine to work on the Vulture???

It might have been the right decision (cancel 900-1000hp engine to work on 1800-2400hp engine) but with the notoriety of the Manchester fiasco I would think people weren't in a hurry to line up to take credit for it. 
Canceling the Whirlwind in order to build all those trouble free Typhoons probably didn't look like a career boosting note on the resume in 1941-42 either. 

While in a cold analytical look, it was the right decision to cancel both the Peregrine and the Whirlwind the fact that the projects they canceled in favor of both had sever problems seems to have perpetuated many of the "excuses" given at the time. 
While a government doesn't have to give excuses, excuses were given at the time. Unfortunately a number of the excuses do not hold up. 

Like the one you gave about the Hurricane holding 50% more cannon ammo. While true on the surface there was nothing to prevent continued production of Whirlwinds with belt feed cannon which not only would have eliminated the difference but given the Whirlwind a 33% advantage.


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## wuzak (Mar 30, 2012)

Shortround6 said:


> Who was going to admit they canceled the Peregrine to work on the Vulture???
> 
> It might have been the right decision (cancel 900-1000hp engine to work on 1800-2400hp engine) but with the notoriety of the Manchester fiasco I would think people weren't in a hurry to line up to take credit for it.
> Canceling the Whirlwind in order to build all those trouble free Typhoons probably didn't look like a career boosting note on the resume in 1941-42 either.



The Peregrine wasn't cancelled in favour of the Vulture. Both programs were suspended during 1940 (BoB) and cancelled in 1941.


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## Shortround6 (Mar 30, 2012)

A bit more on the "comedy of errors".

Petter and Westland themselves. 

One of the less than stellar features of the prototype was that the exhaust pipe was routed through the fuel tank and wing to the trailing edge is an attempt to hold drag to a minimum. This would also hold any thrust due the the exhaust to a minimum in addition to the fire hazard and the hazard of leaking high temperature exhaust gasses into areas of the airframe not able to withstand them. This last nearly caused the loss of the Prototype when an exhaust leak severed an aileron control rod. Another delay while the exhaust and corresponding area of the wing were redesigned and modified. 

We are told that Dowding didn't think much of the Whirlwind for fighter v fighter. That may be but the intended replacement for the Whirlwind was the Bristol Beaufighter. However great the Beaufighter was at a number of jobs the Whirlwind could never do, I don't think that fighter v fighter against 109s was one of them. 

The Air Ministry had an off--on, then off--then on then off once again policy as to the suitability of the Whirlwind for tropical use. Not a conspiracy against the whirlwind as those were confusing times but a more clear headed approach as to what aircraft were going where would have helped out more than one company. The Tropical requirement was NOT part of the intital specification. Then it was added, then it was taken out when production was limited, then it was added back in and then finally dropped. Since tropical requirements affect things like radiator and oil cooler sizes and air flows through the radiators and oil coolers this flip-flopping did nothing to speed up development or production. 

Sweeping under the rug.
Some accounts say that fitting of the bomb racks "saved" the Whirlwind. the Decision to stop Whirlwind production was made in 1940 when the decision to stop Peregrine production was made. The Bomb racks were not fitted to operational aircraft until Aug/Sept of 1942. No. 263 Squadron made it's first flight into enemy territory in Jan 1941 and No. 137 Squadron sent a couple of planes on the Squadrons first combat operation to France on 24th Oct 1941. I guess I was off by 2-3 months. 

Peregrine was canceled in 1940 to allow greater effort on the Merlin and Griffon, Fair enough. But the Vulture staggered on until the fall of 1941 or, according to one source the spring of 1942. Misprint? there is also a difference between the date a decision is made and the final delivery.


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## Shortround6 (Mar 31, 2012)

wuzak said:


> The Peregrine wasn't cancelled in favour of the Vulture. Both programs were suspended during 1940 (BoB) and cancelled in 1941.



I would like to see some exact timing. I don't doubt that both were suspended during the BoB. Both _may_ have been canceled in 1941.

_BUT_ there is an awful lot of of 1941. While I know that disbanding a design team is not the same as end of production both the Peregrine and the Vulture have different end of production dates in different sources. Might be the last couple of engines assembled from parts? The Vulture doesn't stop production until march or April of 1942, the decision to end the program could have come much earlier however. 
There seem to be 2 Peregrines The MK I and MK II (reverse rotation?) and a paper version of about 1000hp, how far that one got I have no idea. 
The Vulture has 3 marks. The MK I (87 octane?), the MK II (100 octane)and the MK V, which leaves one wondering what happened to the MK III and the MK IV. Also how much effort was going into finding solutions to the Vultures woes in 1941?

The Vulture V is often referred to as a 2500hp engine ( sometimes 3000hp is said to have been hit in tests?) which would have meant a 1250hp Peregrine if developed to the same level. 

Once again I say that stopping work on a 800-1000hp engine in favor of a 2000hp engine was the right decision. The 2000hp engine had many more applications (sales). Unfortunately the 2000hp engine wanting came up wanting.


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## wuzak (Mar 31, 2012)

Not sure about the Mk III, but the RRHT gave me some data for the IV and V.

From the RRHT:



> The take off rating of the Vulture II is given as 1800bhp at 3200rpm and +6 lb boost: for the Mk.IV V, the 'fighter' engines, t/o power is given as 1955bhp at 3200rpm and +9lb boost.





> I have not been able to find anything to substantiate that the Vulture attained 3000hp on occasions but the Vulture V is known to have reached 2500hp, and it is possible that, under the right conditions of test, 3000hp was achieved.


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## NiallC (Apr 7, 2012)

Shortround6 said:


> A bit more on the "comedy of errors".
> 
> One of the less than stellar features of the prototype was that the exhaust pipe was routed through the fuel tank and wing to the trailing edge is an attempt to hold drag to a minimum. This would also hold any thrust due the the exhaust to a minimum in addition to the fire hazard and the hazard of leaking high temperature exhaust gasses into areas of the airframe not able to withstand them. This last nearly caused the loss of the Prototype when an exhaust leak severed an aileron control rod. Another delay while the exhaust and corresponding area of the wing were redesigned and modified.
> 
> Peregrine was canceled in 1940 to allow greater effort on the Merlin and Griffon, Fair enough. But the Vulture staggered on until the fall of 1941 or, according to one source the spring of 1942. Misprint? there is also a difference between the date a decision is made and the final delivery.



I’m afraid that the "exhaust ran through the fuel tank" is among the top 10 Whirlwind myths. Sadly, I think it originates with the memoirs of Westland test pilot Hal Penrose and, even more sadly, it’s now been repeated so many times it’s become “true”. At no point in its development did the Whirlwind prototype’s exhaust system run through the fuel tank: right next to it, but not through it. The routing of the 1st prototype’s exhaust and its cooling duct can be seen in the wing spars of the production aircraft: the swaged holes in the spar webs through which the duct passed were left in place even though they were redundant once the exhaust system had been redesigned. It doesn’t go through the tank. The aileron control rods do pass through the rear tank on all Whirlwinds and perhaps that's where the confusion arose.

There seems to be some long-running confusion about timing. The Whirlwind programme was cancelled in its entirety in October 1939 (not 1940). 114 aircraft were reinstated in December 1939 after both Westland and Rolls persuaded the Air Ministry that a substantial quantity of part-manufactured components for both airframes and engines had been made that would otherwise be scrap. 

This is the issue as I see it: it’s been stated (or at least cut-and-pasted from book to book and website to site) repeatedly that Rolls-Royce cancelled this or that engine programme in order to focus its energies on the Merlin (or Griffon or whatever), but I wonder how credible this is. At the time Rolls was a one-customer company. It had neither licensed its products to others nor courted the civil market. The Air Ministry was its only customer. That ministry set Rolls’ prices (or at least its unit profits) and either directly funded Rolls’ capital expenditure or underwrote it through the Capital Clause (thereby absolving the company from pretty much all commercial risk). Handley-Page described his company – which was in an identical position – as being nationalised in all but name. Was Rolls really in a position to unilaterally cancel anything? To decide what programmes it focussed its energies on? Or did it simply build what was on its order book? Once the Whirlwind was cancelled and when it was clear both that the Peregrine could not be de-rated to replace the Kestrel XXX for the Miles Master and that the Gloster F.9/37 would be built, if it was ever to be built, with Taurus rather than Peregrine engines, the Peregrine order book was empty. It never was cancelled: it just died because there was no application for it and no prospect of any. The death of the Vulture is rather later, but for much the same reasons.

HTH
Niall


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## Shortround6 (Apr 7, 2012)

Thank you for the correction. Not going through the tank does make more sense but right next to it doesn't sound a whole lot better even if it is a pipe within a pipe. 

as far as this goes:
"That ministry set Rolls’ prices (or at least its unit profits) and either directly funded Rolls’ capital expenditure or underwrote it through the Capital Clause (thereby absolving the company from pretty much all commercial risk). Handley-Page described his company – which was in an identical position – as being nationalised in all but name. Was Rolls really in a position to unilaterally cancel anything? To decide what programmes it focussed its energies on? Or did it simply build what was on its order book?"

Rolls may not have been in a position to unilaterally cancel a project or program but I believe it was in a position to make some rather strong recommendations about what it could and could not do. 

Allison had been in a similar position around 1935-37 when the US government (it's only customer) wanted Allison to develop fuel injection in addition to the the other projects they were working on. Allison told them they didn't have the resources to handle all the projects and do the fuel injection and to pick which projects they really wanted. The Fuel injection was shelved. 
Rolls may have given the Air Ministry some similar choices. Out of 5 projects pick 3 or something along those lines, of course a short report giving projected out comes of each project would be included allowing Rolls management some capacity to 'steer' the decision. 

I am not sure why the Peregrine could not be de-rated but it would have been several hundred pounds heavier than Kestrel XXX and if de-rated to the same power level would have been a worse choice.


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## Edgar Brooks (Apr 9, 2012)

As Shortround says, R-R did not cancel the Peregrine, but they made it plain that any continuation would have a serious effect on the Vulture (still a going concern in 1940/41,) and various Merlins, even delaying the Griffon. At first, Bulman, who was in charge of a Ministry department, D.E.M. (Engine Manufacture?) at the time, asked them to continue with research and work on making 100 octane usable, but at a reduced level of urgency. 
The Whirlwind order was not cancelled in 1939, the order was simply not confirmed; I realise that this might seem like playing with words, but the first prototype had handed engines, while the 2nd. prototype did not, and the Ministry wanted to know if there was any difference in handling before going ahead. The second prototype did not fly until Spring 1939, and did not go to A. A.E.E., Martlesham for full service trials until September 1939. Adding to the delay was the production programme, for Peregrines, which was only 8 in February 1940, 12 in March, 22 in April, rising to 48 in December. Add to that Westland's estimate, to the Ministry of a maximum production of two airframes per week (though they told Dowding it was only one p.w,) and it was realised that production would never keep pace with losses (later, 4 were lost in one day during the Channel Dash.) The Minister for Air, Sir Wilfrid Freeman, in June 1940, ordered that no more should be produced, and 30-10-40, Beaverbrook told Dowding that he would continue with material to hand, then cease production.
Petter visited the Whirlwind squadron in November 1940, and found that, out of the (only) eight airframes they had, there were just three that were serviceable, which didn't help their case at all.


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## Shortround6 (Apr 9, 2012)

To continue the comedy of errors, that squadron (in 1940) was in Scotland, about 400 miles from the Westland factory and while not the furtherest from the factory one could get and still be in the British Isles was obviously not close enough to get decent factory support for a squadron trying to bring a new type to service. I believe (so the the "story" goes) that Westland was making 4-5 Lysanders a week at the time and had received no clear directive from the Air Ministry as to which program should receive priority. 
I am sure that a number of other programs, both in England and and in other countries, if examined in the same way, could be seen as a comedy of errors also. I am not claiming that there was a planned conspiracy or group in the Air Ministry that was "out to get" either Petter or Westland.


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## Edgar Brooks (Apr 9, 2012)

263 was in Scotland because it was virtually a new Squadron, since it had lost most of its aircrew when Glorious was sunk, and it needed to work up, before joining the Battle; it was July 9th before it received its first Whirlwind, so had to use Hurricanes instead. 
17-10-40 Dowding told Beaverbrook,"I purposely put No.263 Squadron well out of the way because I know Westlands and I knew what a packet of trouble the squadron would be in for. I cannot put them anywhere in the South because I cannot carry any "passengers" in that part of the world. All the squadrons there have got to be fighting fit. It is too soon yet to form an opinion, because the squadron has never had enough Whirwinds serviceable for any operational work, but my present impression is that they will have too high a gliding and landing speed for use as a nightfighter, and it is rather an uneconomical vehicle for carrying 4 cannon guns by day. Directly they can be whacked up to a complete squadron, I will send them down South and see how they shape as a fighting machine."
When Petter visited 263 he noted that the majority of problems were with the engines, and, in Scotland, 263 was a lot closer to Derby than Yeovilton. 
I think that the idea that Westland had received no clear orders about the Whirlwind is rather wide of the mark, as a paragraph from a "history" of the aircraft shows," Quite apart from this trouble over the engines, there were other substantial difficulties. The firm were anxious to have as few changes in design as possible in the production machines as they felt that deliveries would be held up. The Air Ministry however were determined that as the aircraft would not be in service until 1940, it must be as up to date as possible. This meant of course many alterations some of which were suggested at the Final Conference on 1-3-39. They were nearly all items of equipment. Mr. Petter sent in a list showing delays which would accrue in production if these modifications were included. The Air Ministry thought these delays were excessive and were estimated on purpose to avoid having to do the modifications on early production machines. The friction between the Air Ministry and the firm was gradually dispelled, after the firm had been given a sharp rap over the knuckles. A concession was allowed them and the modifications were only to be applied from the 25th aircraft onwards, although they were all specified in the production specification. It appears that the firm had been neglecting the Air Ministry's advance notification of equipment requirements and consequently no trial installations had been started. This may account for the first prototype being given over to a concentrated programme of trial installations that was only completed in December 1940. The only other outstanding feature of the period while the Whirlwind was coming into production was the fuss over the maintenance qualities of the type. The director of Repair and Maintenance had criticised them as being too complicated, and A A.E.E. were asked to make recommendations for improving them."
It rather sounds from this as if Westlands didn't help their own case very much, and, coupled with R-R's reluctance over the Peregrine, the Whirlwind had no chance.
Oddly, the Hurricane was slated to finish production in March/May 1941, but, possibly due to the Whirlwind's "failure," it stayed in production for three more years, doing the anti-tank attack work that Dowding had foreseen for the Whirlwind, and adding rockets and 40mm cannon to its armament, as well, while being easier to repair, using one engine, and capable of better performance at 25,000'+. 
Add to this the one/two airframes Westland could produce weekly, and set it against the hundreds of Spitfires and Seafires that they did produce, at about 6 per week, and it's fairly easy to see why the right decision was made (however much I like the look of the Whirlwind.)


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## NiallC (Apr 9, 2012)

Edgar Brooks said:


> The Whirlwind order was not cancelled in 1939, the order was simply not confirmed; I realise that this might seem like playing with words, but the first prototype had handed engines, while the 2nd. prototype did not, and the Ministry wanted to know if there was any difference in handling before going ahead. The second prototype did not fly until Spring 1939, and did not go to A. A.E.E., Martlesham for full service trials until September 1939. Adding to the delay was the production programme, for Peregrines, which was only 8 in February 1940, 12 in March, 22 in April, rising to 48 in December.



Sorry to disagree Edgar, but the record says otherwise. You’re absolutely correct that the second prototype did not physically go to A&AEE until late August 1939, but that was not the first opportunity that A&AEE pilots had been given to express an opinion of the aircraft. 4 pilots from A&AEE (then at Martlesham) each briefly flew the first prototype at RAF Boscombe Down on December 30th 1938. On the basis of their highly positive report, Freeman and Tedder thought that the aircraft should be ordered into production. A firm order for 200 aircraft was placed early in January 1939 – that being the maximum number of aircraft Westland could commit to completing by July 1941. While Rolls-Royce was advised of the resulting Peregrine requirement and was given an ITP for 440 engines (200 pairs plus 10% spares), no firm order was placed for the engines because, as you note, no decision could be taken as to whether counter-rotating engines were really needed until the second prototype (with identical, right-hand engines) had flown. That prototype flew on 29 March 1939 and two A&AEE pilots flew it on 15 April (again at Boscombe). They found that the handling was largely the same as that of the first prototype, although the lack of elevator authority when landing was even more marked on the second aircraft than the first. The counter-rotating engines were duly dropped and the Peregrine order confirmed for right-hand tractor engines (i.e. Peregrine Is). Rolls was told to plan for an output of an additional 1960 Peregrines to cover planned Whirlwind production from Westland and Castle Bromwich. (As a point of interest Rolls was told at the same time to plan for 1560 Vultures). 

The Whirlwind order was cancelled at Freeman’s suggestion in October 1939 as a part of the “First wartime production plan” (aka the “Harrogate Plan”). The decision was rubber-stamped by the Supply Committee at its 86th-88th meetings (12th-14th October): ‘…orders for Whirlwind aircraft, Peregrine engines and allied equipment should be cancelled at once and all work on them stopped. Jigs and tools and semi-manufactured material should be put in store pending further instructions.’

This prompted a protest from Lord Aberconway, Westland’s chairman, who later told Freeman that so much part-finished material was available that “around 100” Whirlwinds could be built at almost no additional cost. Eric Mensforth (joint MD at Westland) re-stated this case at an interview with the Supply Committee in mid November. Having satisfied itself that a similar quantity of part-finished forgings and castings for Peregrines had also been made, the committee re-instated an order for 114 aircraft in December 1939 ‘to use up the material and avoid waste.’ 26 of these were to be delivered as unarmed aircraft for the PDU, the remainder as fighters. 

Freeman and Beaverbrook’s later comments are a bit of a red herring. Freeman’s June ’40 comment was in the context of contemporary Air Ministry discussion of the possibility of a further Whirlwind order (prompted by Teddy Petter’s numerous “Whirlwind MK II” proposals). Freeman shut down this debate with a terse memo: ‘no new Whirlwinds’. Note ‘new’. Beaverbrook’s October comments don’t represent a new decision on his part – rather, leaving in place one taken by others a year earlier. Beaverbrook seems to have been prepared to have re-instated the Whirlwind programme if Dowding thought highly of the aircraft. Dowding didn’t. So Beaverbrook let the decision stand.

It’s often been said that delayed Peregrine deliveries were a primary cause of slow deliveries of production Whirlwinds in 1940, but the numbers make me wonder. MAP’s own delivery stats indicate Peregrine deliveries (actuals rather than plan) of 12 per month in Q2, 4 per month in Q3 and 15 per month in Q4. This is far in excess (and in advance) of Whirlwind production so perhaps the reason for delay lies elsewhere. In its correspondence with Fighter Command, Westland cited slow/late deliveries of self-sealing tanks as the primary cause of slow deliveries of the aircraft. Who knows.

Shortround: Like you I’m unclear about what the supposed difficulty was in de-rating the Peregrine. It was fairly common for the RAF to order de-rated engines for training applications: trading performance for longer overhaul intervals. The most explicit first-hand, contemporary reference I’ve found is the minutes of a meeting between Ernest Hives of Rolls-Royce and Wilfrid Freeman (then AMDP) on 14th October 1939: “It was agreed that Peregrine engines could not effectively be de-rated (eg with Kestrel type superchargers) for installation in Masters for which the Mercury XV must be provided after all possible Kestrel XXX engines have been secured.” Which doesn’t really tell us very much.

HTH
Niall


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## Shortround6 (Apr 9, 2012)

You are quite right that Petter and Westland did not help their own case. Petter was still shooting himself in the foot when he refused to put bigger tyres on the Folland Gnat and bulge the landing gear doors and so helped loose the contract for the NATO light fighter to the Aeritalia G-91. The contract may have been lost anyway due to politics (or other performance ) but refusal to meet such requirements as ground loading just gave them excuses. 

Dowding's reasons might carry a bit more weight if there had been _NO_ squadrons in the south equipped with either Gladiators, Defiants or Blenheim day fighters. While 263 Squadron shouldn't have been in No 11 group that still leaves an awful lot of the south (like Cornwall 

Not sure were the Night fighter idea was coming from either. Of course they did have a number of night fighter squadrons with no radar at that time. 

It would be interesting to see the number of employees and the sq footage of factroy space that Westland had in late 1939 and early 1940 compared to what it had when it was turning out hundreds of Spitfires too.


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## NiallC (Apr 9, 2012)

Edgar Brooks said:


> When Petter visited 263 he noted that the majority of problems were with the engines



Hmm. I wonder whether this would be the first time a designer has played a little fast and loose with the facts when defending his creation? 13 Group organised a conference, attended by Westland, at Drem on September 25th 1940 to discuss 263 Squadron’s problems with the Whirlwind, the report from which notes ‘The Rolls-Royce Peregrine has given very little trouble’. There had been a single in-flight engine failure, the cause of which was found to be fuel filters clogged with tank sealant, it apparently being Westland’s standard practice to seal leaking tanks, post-manufacture, with Bostick! The rest of the report is given over to a litany of more serious failures – all airframe and systems-related: fractures in the convoluted carburettor air intake ducting, repeated hydraulic failures (caused by poor-quality plumbing), collapsing canopies, disintegrating slats, slats popping off their tracks, inability to maintain rated engine boost at altitude (found to be due to more poor-quality plumbing), fragile tailwheel oleos and failing wingtips. It was this last issue which caused the squadron engineering officer to ground the aircraft, prompted by pilot concerns that a wingtip failure in flight might jam the ailerons.

Many of these problems should have been picked up during development flying, but the two prototypes actually flew very few hours before the first production aircraft were delivered. This seems largely because of Petter’s inflexibility regarding modifications as you note. Standard ministry practice was to approve such mods on the basis of a mockup, but Petter insisted on making trial installations of them all on the two prototypes – which were accordingly grounded for long periods of time when they should have been piling on the hours. As an example, the second prototype L6845, had only 65 total airframe hours to its name when it was delivered to 25 Squadron for operational trials in May 1940 – nearly 18 months after its first flight.

Shortround: Whatever we may think of the usefulness of Gladiators, Defiants and Blenheims in Fighter Command at the time, they were at least serviceable and operationally fit at a time when the Whirlwind was not. The Fighter Command state reports show shockingly poor Whirlwind serviceability throughout the summer of 1940 and 263 Squadron does not appear as “Operational” in the Command OrBat until 22nd December 1940 – and even then only 1 section is shown as being so.

I don’t have the factory area and workforce data to hand right now, but my sense of it is that almost all of the expansion of Westland capacity took place earlier than this: mainly when John Brown took a majority shareholding in late ’38 and another phase when Westland took over Petters old engine factory – again pre-war. Ironically and interestingly, according to MAP’s figures Westland airframe output averaged 70 aircraft per month in Q3 1940 and 65 in Q4, figures it did not achieve again at any time during the war. The closest it got was in Q2 1945 – 66 aircraft per month (61 Spit/Seafires and 5 others – presumably Welkins). So the capacity was certainly there in mid-late 1940, but was devoted to producing Lysanders not Whirlwinds.
Niall


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## wuzak (Apr 9, 2012)

I wonder if the MAP considered getting Westlands to adopt the Supermarine Type 327 design - at least for protootyping. The 327 used Merlins and promised much higher performance than the Whirlwind (or anything in the air at the time), and could easily take 4 cannon - it was supposed to take 6, but the MAP thought the installation impractical.

The MAP was also wary about how long it took Supermarines to produce prototypes and then production machines. I suppose Westlands were no better.


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## Edgar Brooks (Apr 10, 2012)

Shortround6 said:


> Dowding's reasons might carry a bit more weight if there had been _NO_ squadrons in the south equipped with either Gladiators, Defiants or Blenheim day fighters. While 263 Squadron shouldn't have been in No 11 group that still leaves an awful lot of the south (like Cornwall)


Normal squadron complement was 15 (at least) airframes; Dowding couldn't (and wouldn't) shift an incomplete squadron anywhere while they were still working up. 263 did have Hurricanes, and did fly operations with them while they were in Scotland.


> Not sure were the Night fighter idea was coming from either. Of course they did have a number of night fighter squadrons with no radar at that time.


The idea came from 263's C.O. If Spitfires and Hurricanes were being pressed into service as nightfighters in 1940, I can see why an aircraft, with the armament of the Whirlwind, would be considered, as well, since it would have been able to down German bombers, whatever their armour. Even the Typhoon, at one stage, was tested as a nightfighter, but rejected because it was felt that the work was too much for one man.


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## fastmongrel (Apr 10, 2012)

Muzzle flash on the Whirlwind would have destroyed the night vision of the pilot. I can think of worse aircraft than the Whirlwind for night fighting but not many. Possibly the best use of the Whirlwind would have been low level recce, I believe down low it could outrun a Spit so a cleaned up unarmed version with cropped supercharger impellors would have been a hot ship. 

ps I still have my 40 year old Airfix Whirlwind love that little model one of the first that I built where I knew what I was doing. Its missing the tail wheel and the port prop from being badly stored in the loft but wouldnt throw it out for any money.


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## tomo pauk (May 19, 2013)

Since the Whirlwind 'deserves' many threads, guess I'll dust off this one. 
So maybe it would be better to re-engine the Whirly, some time in 1940/41, with single Sabre? Should be faster than Typhoon...
Maybe later strap on the Griffon for the needs of FAA, service use in 1943 and on? The Fowler flaps and slats could come in handy here.

How about Hercules, or R-2800? Of course, for all the proposals the cannons go into the wings.


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## Shortround6 (May 19, 2013)

You seem to have this strange fascination with keeping the outward appearance of _some_ parts of airframe while totally redesigning the interior structure. 

You don't actually save much. Keep fuselage from the cockpit back (if you are lucky) and the outer wing panels? 

Regardless of what you do with the nose the wing from engine nacelle to engine nacelle will have to be redone. To fit the landing gear if nothing else. Changing the location of major weights changes stress loads even if total weights are the same. 

For a couple of light plane single to twin conversions look at the Beechcraft Bonanza and Travel air and the Piper twin Comanche.


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## tomo pauk (May 19, 2013)

Shortround6 said:


> You seem to have this strange fascination with keeping the outward appearance of _some_ parts of airframe while totally redesigning the interior structure.



With Whirlwind, it's the combination of (almost) clear view canopy, Fowler flaps, slats and retractable tailwheel, all in a single plane - unparalleled in ww2? That's fascinating to me 



> You don't actually save much. Keep fuselage from the cockpit back (if you are lucky) and the outer wing panels?



I save more than when Typhoon was developed in Tempest, P-51D in -H, Fw-190 in Ta-152, Bf-109E into -F.... Even the P-36 grew steep in weight to become mid-war P-40, like K for example.
added: more frugal than turning the Hurricane production lines into Typhoon production lines 



> Regardless of what you do with the nose the wing from engine nacelle to engine nacelle will have to be redone. To fit the landing gear if nothing else. Changing the location of major weights changes stress loads even if total weights are the same.



Agreed.



> For a couple of light plane single to twin conversions look at the Beechcraft Bonanza and Travel air and the Piper twin Comanche.



I'm trying to do the opposite - turn the twin into a single


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## Shortround6 (May 19, 2013)

tomo pauk said:


> With Whirlwind, it's the combination of (almost) clear view canopy, Fowler flaps, slats and retractable tailwheel, all in a single plane - unparalleled in ww2? That's fascinating to me



The need for the slats is dubious. Especially with the Fowler flaps. Slats do a lot more for keeping aileron control at really low speeds (like landing) than they do for turning. I am not sure if they were wired shut in operation of the Whirlwind, accounts may differ. 





tomo pauk said:


> I save more than when Typhoon was developed in Tempest, P-51D in -H, Fw-190 in Ta-152, Bf-109E into -F.... Even the P-36 grew steep in weight to become mid-war P-40, like K for example.
> added: more frugal than turning the Hurricane production lines into Typhoon production lines



True in some cases but they had a lot more invested is some of those production lines. And a question is how much some of them were changed, a lot for the P-51s or a little for the P-36/P-40, It gained a lot of weight and may have needed some parts beefed up but could you build a P-40 wing using many of the same jigs/fixtures as the P-36 wing? how much of the fuselage structure changed? 





tomo pauk said:


> I'm trying to do the opposite - turn the twin into a single



The Travel Air replaced a 225-240hp six with pairs of 160-200hp fours, kept the same cabin/payload area. It Borrowed the main spar from a bigger twin and the landing gear from the T-34 trainer ( two seat trainer/narrow fuselage Bonanza). T-34 could land on carriers so the landing gear was heavier duty than the regular Bonaza landing gear. Beech already had some of the bits and pieces laying around. And they weren't trying to change the payload area (cabin) which for fighter planes is the gun location. 

Given what we NOW KNOW about the Sabre they might have been better off keeping the Whirlwind and junking the Typhoon


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## yulzari (May 19, 2013)

If I may give my summary of the Whirlwind saga.

It was intended as the future way, to have a 1600bhp power day fighters now (ie when the decision was made in 1935) and a 2,500bhp day fighter in the mid 1940's using known (ie Kestrel based) power units and a future proof armament. In the initial enthusiasm it was seen as the future standard and the Tornado/Typhoon as a back up, as was the Sabre. The Vulture was a bomber project that could be diverted into a fighter. The Spitfire was not, initially, intended as anything more than a better Hurricane supplement pending Whirlwind or Tornado production and there were doubts there would be another production contract after the first one.

Now, as we know, things didn't follow this early intention.

The Whirlwind airframe had minor faults, all easily dealt with some sort of MkII version (rejigging the tankage arrangement, belt feed cannon etc.) The Peregrine could have followed a Merlin type development and given 1,300 bhp by 1944 (insert your preferred power output) with 2 stage blowers and perform at higher altitudes.

The Whirwind could have been fitted with a number of alternative engines as Westlands themselves suggested (eg Taurus, Allison, Merlin) but the best would have been the developed original.

It could have been a very useable day fighter throughout the war but at a production cost. In hindsight the decision to abandon it was a very reasonable one. The decision to rely on the Tornado/Typhoon instead, in hindsight, was worse.

That decision, at the time, looked even more reasonable and was the correct one with the information they had at the time.


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## tomo pauk (May 19, 2013)

Sensible post 

The 2-stage Peregrine would've been in service in 1943?, however, that would've involved greater installed engine weight drag. The simple 2-speed Merlin should offer about the same power, for about same weight drag penalty, while being available earlier. 
The Allied war effort was not dependent on Typhoon/Tornado, so, even if those weren't around, the Allies would've done pretty much the same. 



Shortround6 said:


> The need for the slats is dubious. Especially with the Fowler flaps. Slats do a lot more for keeping aileron control at really low speeds (like landing) than they do for turning. I am not sure if they were wired shut in operation of the Whirlwind, accounts may differ.



Thanks for the input. 
One of proposed applications of the single-engined Whirly is the fighter for FAA, where the slats can help.



> True in some cases but they had a lot more invested is some of those production lines. And a question is how much some of them were changed, a lot for the P-51s or a little for the P-36/P-40, It gained a lot of weight and may have needed some parts beefed up but could you build a P-40 wing using many of the same jigs/fixtures as the P-36 wing? how much of the fuselage structure changed?



Westland started to build Spitfires, so we can asses what size of the investment that was? 
Hmmm, Whirly with a single Merlin (45, XX?), with slightly clipped wings?



> The Travel Air replaced a 225-240hp six with pairs of 160-200hp fours, kept the same cabin/payload area. It Borrowed the main spar from a bigger twin and the landing gear from the T-34 trainer ( two seat trainer/narrow fuselage Bonanza). T-34 could land on carriers so the landing gear was heavier duty than the regular Bonaza landing gear. Beech already had some of the bits and pieces laying around.



Thanks again.



> And they weren't trying to change the payload area (cabin) which for fighter planes is the gun location.



The cannons would've gone into where once the nacelle was, the ammo into where once the inter-spar fuel tank was. New fuel oil tanks go where the ammo drums were, engine in front of it.



> Given what we NOW KNOW about the Sabre they might have been better off keeping the Whirlwind and junking the Typhoon



Maybe Peter should've designed the Whirly around Merlins in the 1st place? Or maybe S. Camm should've designed Typhoon around thinner wing at 1st? 

What about this: RR and Fairey form a design studio that would iron out the bugs from Vulture? Bristol and A-Siddeley do the same for Centaurus? Or, employ the design engineers from those two smaller firms into major ones?


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## Shortround6 (May 19, 2013)

The decision to use 1 engine instead of two 12 cylinder engines would stand up a lot better if the Single engine was a big 12 or 14 instead of a 24 cylinder (or double 12). While manufacturing and Maintenance may be a bit simpler on the 24 it is nowhere near as simple as a going from 2 engines to 1 implies.


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## tomo pauk (May 19, 2013)

Agreed, the Sabre was a handful in most of the categories.

FWIW, 3 views of two sleek British fighters, Whirly and Tempest I (images found at warbirdsresourcegroup.org):


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## yulzari (May 19, 2013)

tomo pauk said:


> Sensible post
> 
> 
> The Allied war effort was not dependent on Typhoon/Tornado, so, even if those weren't around, the Allies would've done pretty much the same.


At the time the decisions needed to be made the Allies were UK and France. The USA was 4 years away from defending democracy. The RAF was intending to be dependent upon the Tornado/Typhoon. Continuing Hurricane production and Spitfire developments were to fill in the gap when that programme was failing.


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## wuzak (May 19, 2013)

yulzari said:


> It was intended as the future way, to have a 1600bhp power day fighters now (ie when the decision was made in 1935) and a 2,500bhp day fighter in the mid 1940's using known (ie Kestrel based) power units and a future proof armament. In the initial enthusiasm it was seen as the future standard and the Tornado/Typhoon as a back up, as was the Sabre.



The Typhoon/Tornado were to be Hurricane/Spitfire replacements. Not a backup to the Whirlwind.

The Whirlwind was teh cannon fighter - RAF theory at the time being that it needed a twin to carry the armament.




yulzari said:


> The Spitfire was not, initially, intended as anything more than a better Hurricane supplement pending Whirlwind or Tornado production and there were doubts there would be another production contract after the first one.



You have a fascination that the Spitfire was a stop gap. Nothing could be further from the truth.

The Whirwind was never intended to replace the Spitfire or Hurricane. It was a complementary airframe, a heavily armed destroyer.

The Spitfire was ordered into production before the process that led to the Typhoon/Tornado program. The Spitfire was not holding the line until they were developed. The Spitfire was the premier fighter. It was intended to replaced with newer, better airframes in the future, but that plan failed.

The prospect at cancellation of the Spitfire was not due to anything more suitable being available, buy the Air Ministry's exasperation with Supermarine and the time it was taking to get production up to speed.


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## delcyros (May 19, 2013)

I guess, the Westland Whirlwind could be turned into a much superior interceptor (air defense), had Westland considered to install jet engines instead of the Peregrines. The Westland Welland W2/B comes to mind...


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## CobberKane (May 19, 2013)

wuzak said:


> The Whirwind was never intended to replace the Spitfire or Hurricane. .


 
From what I've read there was at least some consideration of the Whirlwind as a spitfire replacement. In his pithily named book "Spitfire" Leo Mckinstry makes note of it, and from recollection notes Churchill was an enthusiast. it seems what sunk the Whirlwind was that it there always seemed to be a better alternative to go with; the Spitfire proved to have more stretch than anyone anticipated, and the Typhoon was looking good. Possibly the Whilwind might have been able to be developed into a fighter bomber like the Typhoon more quickly, but no-one knew the Napier sabre was going to prove problematic, they only knew the Kestrel was problematic now.
I believe the Whirlwind also had very high landing speeds, which may also have been a consideration.


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## Dogwalker (May 20, 2013)

A licence produced Hispano Suiza 12Y (of the best version available for the licensed production in, let's say, 1937). A little shorter, lower, lighter, and a little wider than the Peregrine.


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## Kryten (May 20, 2013)

[[I believe the Whirlwind also had very high landing speeds, which may also have been a consideration.]]

Higher than a Spit or Hurricane , Flaps,undercart down stall was 85mph compared to 64mph for spit mk1.

From V Binghams book pilots notes-
Approach.
When engine assisted the speed should be about 110/115mph, Throttles should not be closed until after flattening out.
With a Glide approach the speed should be kept at 125mph ASI

in other words not unduly high, it was also reported to require longer strips than fighter command possesed, yet flew out of fighter airfields on numerous ops!
Another fallacy was you couldn't open the canopy in flight, complete bunkum as there are pictures of just that on operational sqdn's.

There are a lot of plainly incorrect myths about this aircraft, and to be blunt, most originated from people who never flew one or had no wish to see it continue, politics played a very large part in it's demise, not helped at all by Petters attitude to the powers that be and Westlands dismal production rates!

Pilots and Sqdn Commanders interviewed by V Bingham all considered the aircraft to have excellent handling and maneuverability, superb visibility and firepower, yet nearly all commented on the lack of cross feed of the tanks and the boost drop off over 15k ft, not a perfect plane by far but plenty of development room had the will, and requirement been there!


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## yulzari (May 20, 2013)

I think there may be some confusion between the original purpose of the, quite limited, original Spitfire contract and the early decision to expand it's production. Supermarine were making a pig's breakfast of making production Spitfires and there were doubts that they could cope with further large orders. At the same time the shadow factory concept was being born.

Westlands were no better at Whirlwinds, especially as they had large Lysander contracts in hand. The Spitfire was proving to be better than expected with further potential; even with the crude propellor it first received. 

It was decided that the Spitfire was a better shadow production bet than a Whirlwind for a variety of reasons that have been touched on in this and other Whirlwind threads so then the Spitfire was chosen for large scale copying in shadow factories.

Once the Whirlwind missed out on shadow factory production it was dead in the water as a major type and production went on to both use up the parts already made and to get a 4x20mm cannon airframe out.

But, returning to the very original Spitfire order, it was not, at the time it was ordered, seen as a major ongoing day fighter standard. It soon proved itself and thus soon won it's place in the shadow factory scheme and future fame but, at the time of the first order, the Whirlwind (albeit to a different Requirement) was seen by some as the way forward. 

We so easily forget that these things began in 1934 planning and 1935 requirements so there were 7 years between the first formal thinking of modern day fighters and the Battle of Britain and the period when the Spitfire was a stop gap was very short and very early.


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## Lucky13 (Mar 3, 2015)

I desperately try to find where I found that _Merlins would fit and the airframe could take them, Westland stated in January '41 they could fit merlin XX's into the whirlwind if they wanted it_


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## stona (Mar 3, 2015)

Lucky13 said:


> I desperately try to find where I found that _Merlins would fit and the airframe could take them, Westland stated in January '41 they could fit merlin XX's into the whirlwind if they wanted it_



It was a letter sent by Westland to Leigh Mallory at Fighter Command. It by-passed the normal channels, meaning the Air Ministry, and was an attempt to gain the support of Leigh-Mallory in a last ditch attempt to save the Whirlwind. It came to nothing. It was the Air Ministry and then the Ministry of Aircraft Production that decided which aircraft would be built and how and where, not Fighter Command or even the RAF. The Ministry had already made its decision.
There is no evidence that Westland had in fact solved all the significant problems associated with fitting the Merlin to the Whirlwind, most notably the redesign of the nacelle and main landing gear attachments in order to accommodate the up draught carburettor system of the Merlin.
Cheers
Steve


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## Shortround6 (Mar 3, 2015)

Not to mention larger radiators, large oil coolers, quite possibly larger fuel tanks, different props, change in center of gravity. How much closer the twin Merlin Whirlwind would have been to a short wing Welkin is an interesting subject


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## stona (Mar 3, 2015)

Shortround6 said:


> Not to mention larger radiators, large oil coolers, quite possibly larger fuel tanks, different props, change in center of gravity. How much closer the twin Merlin Whirlwind would have been to a short wing Welkin is an interesting subject



Well, Petter did come up with a suggestion for a smaller diameter four bladed propeller, but as for the rest.....

Cheers

Steve


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## Shortround6 (Mar 3, 2015)

Well, there is your _different_ prop 

And getting even a small 4 blade prop to be as light as the 3 blade on the Peregrine would take some doing.


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## Glider (Mar 3, 2015)

Any change in engine for the Whirlwind would be a huge challenge. It was a very small aircraft and putting a new engine would almost certainly result in unacceptable changes to the structure. Any change is likely to result in a thirstier engine and that would significantly impact the range.

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## Shortround6 (Mar 3, 2015)

Sort of like pulling the Sabre out of a Typhoon and putting a Merlin on each wing and sticking the guns back in the fuselage


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## kool kitty89 (Mar 4, 2015)

Glider said:


> Any change in engine for the Whirlwind would be a huge challenge. It was a very small aircraft and putting a new engine would almost certainly result in unacceptable changes to the structure. Any change is likely to result in a thirstier engine and that would significantly impact the range.


Re-engining it with Taurus or Persius engines might have been more interesting. The Taurus showed a significant performance boost over the pregrines employed on Gloster's F.9/37 ... Perseus is lighter though. (and had fewerproduction/reliability problems -not sure about altitude performance, I know the Mercury had its share of medium altitude rated variants, but not sure about its sleve-valve successor ... mid-high/high alt performance would still be a problem though given the Merlin developed much more in that direction than Bristol's engines)

Aside from interceptor performance, the radials might have been more interesting for a ground attack/intruder platform. (including freeing up wing space from those radiators, potentially for fuel tankage)

Nacelle shape would still be an issue though, landing gear perhaps less so. (Gloster's design seemed to use a more modular engine installation too, so switching over might not be so straightforward)


There's also the issue of the automatic wing slats. If they'd managed to resolve the problems on those, the low speed handling issues (and landing speed in particular) should have been significantly improved.


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## Shortround6 (Mar 4, 2015)

The Taurus engines used in the Gloster F.9/37 were a never repeated experimental model. They _somehow_ gave much more power than any service Taurus ever did (same power at a much higher altitude means more power going to the supercharger). 

Perseus is lighter but it has the streamlining of a barn door, unless you steal them from Lysander production (or Bothas) they may be in short supply, They pretty much use Hercules cylinders. 











Perseus was pretty much abandoned in 1939/40 development wise. 

Low speed handling of the Whirlwind wasn't all that bad, one pilots got used to it. Unfortunately, like the P-38, they stuck fighter pilots used to single engine aircraft in the cockpit with only a few hours of twin engine experience (usually on an Anson) and told them to "get on with it". Slats are not magic, they _only_ work at high angles of attack, and slats only affect the area of the wing behind them. They do nothing for the areas of wing that are not behind them. Unless you 3 point land the plane they probably won't do much good. The high landing speed of the Whirlwind was _only_ in comparison with other British fighters of it's time (1939/40). It was quite comparable to the American P-38, P-39 and P-47. All of which were 20-40mph higher than a P-40 depending on actual landing weight.


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## Glider (Mar 4, 2015)

kool kitty89 said:


> Re-engining it with Taurus or Persius engines might have been more interesting. The Taurus showed a significant performance boost over the pregrines employed on Gloster's F.9/37 ... Perseus is lighter though. (and had fewerproduction/reliability problems -not sure about altitude performance, I know the Mercury had its share of medium altitude rated variants, but not sure about its sleve-valve successor ... mid-high/high alt performance would still be a problem though given the Merlin developed much more in that direction than Bristol's engines)
> 
> Aside from interceptor performance, the radials might have been more interesting for a ground attack/intruder platform. (including freeing up wing space from those radiators, potentially for fuel tankage)
> 
> ...



Good points. I think the problem with a radial is that it would significantly increase the drag, with an inevitable impact on performance. Normally an inlines radiators largely nullify the drag advantage of an inline, but the Whirlwind had cracked this problem.



> Low speed handling of the Whirlwind wasn't all that bad, one pilots got used to it. Unfortunately, like the P-38, they stuck fighter pilots used to single engine aircraft in the cockpit with only a few hours of twin engine experience (usually on an Anson) and told them to "get on with it". Slats are not magic, they only work at high angles of attack, and slats only affect the area of the wing behind them. They do nothing for the areas of wing that are not behind them. Unless you 3 point land the plane they probably won't do much good. The high landing speed of the Whirlwind was only in comparison with other British fighters of it's time (1939/40). It was quite comparable to the American P-38, P-39 and P-47. All of which were 20-40mph higher than a P-40 depending on actual landing weight.



Again good points. The Whirlwind squadrons were given an Oxford so that new pilots could work on their experience with twins as Whirlwinds were too valuable to practice with. However the difference in landing speed between the two must have been pretty scary.


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## Shortround6 (Mar 4, 2015)

Glider said:


> Normally an inlines radiators largely nullify the drag advantage of an inline, but the Whirlwind had cracked this problem.



The inline vs radial drag advantage bounce all over the place depending on what year you are talking about. Some WW I to 1920s radiator designs were terrible but then the rotary and radial engine installations were pretty bad too. At the end of 20s and beginning of the 30s both camps started to "clean up" their acts. Radials got Townend rings and NACA cowls. Inlines tried steam (Goshhawk for one) and switching to glycol coolant instead of water. The operating temperature of glycol allowed smaller radiators (less drag) to be used. Putting the radiator in a duct and not just hanging it out there or putting it in a box with a somewhat streamline out side was still a few years away. While a NACA cowl was a big improvement for radials there was still a long, long way to go to reach even pre-Fw 190 standards. 






The NACA cowl and the wheel pants were good for almost 30mph on the Lockheed Vega but notice there are NO adjustable cowl flaps and internal baffles are pretty sketchy, if there at all. 

One camp and then the other would gain the lead for a while (or at least close the gap) but then other camp would develop something new and close it up or swap leads.

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## Shortround6 (Mar 4, 2015)

duplicate


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## Edgar Brooks (Mar 4, 2015)

Shortround6 said:


> The high landing speed of the Whirlwind was _only_ in comparison with other British fighters of it's time (1939/40). It was quite comparable to the American P-38, P-39 and P-47. All of which were 20-40mph higher than a P-40 depending on actual landing weight.


Not quite; the high landing speed was what (according to Dowding in 1940) made it unsuitable as a nightfighter, which closed off another possible use for it.


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## kool kitty89 (Mar 5, 2015)

Shortround6 said:


> The Taurus engines used in the Gloster F.9/37 were a never repeated experimental model. They _somehow_ gave much more power than any service Taurus ever did (same power at a much higher altitude means more power going to the supercharger).
> 
> Perseus is lighter but it has the streamlining of a barn door, unless you steal them from Lysander production (or Bothas) they may be in short supply, They pretty much use Hercules cylinders.


From recent discussions (particularly the other Whirlwind and British Radial engine threads) it seemed like the Perseus had similar dimensions to the Mercury, but still a good bit larger in diameter than the Taurus, granted. And I recall the Taurus III's performance being compared to the prototype medium altitude engine on the 9/37 (reduced take-off power, significantly increased FTH) but that it didn't seem to see much/any large scale use in production.

The other Whirlwind thread also got into the issue of Lysander production as a major logistical issue for Westland in general. Shifting priority to a similarly powered Whirlwind has technical merits, and almost certainly an overall more useful aircraft than the Lysander was in service but the political side of things with actual production orders and funding would be the issue there. (that said, such a conversion was never even proposed formally -let alone early enough to sway the powers that be, so it's harder to say if it would have been shot down flat)



> Perseus was pretty much abandoned in 1939/40 development wise.


And given the trouble the Taurus ended up having (and engineering commonality with the Hercules), that's unfortunate, but speculation for a separate thread. (and already came up in one of the recent engine threads)

That said, a medium altitude rated Perseus or Mercury would seem to fit well enough weight wise, likely slower due to drag though. (in the multi-role fighter-bomber and possible anti-shiping role it might have been better suited -and able to take more engine damage ... and stay in production after the Perigrine ceased)
Perhaps a more useful adaptation in the interim had the Merlin adaptation been more seriously considered.


I was also pointing out the low-speed characteristics in terms of the added weight of a possible Merlin adaptation. if they'd managed to address the slat functionality during that redesign, increase in wing size/area might not have been necessary. And while the slats only covered the outer wings, the prop wash at the center sections would have increased lift and critical AoA in those regions to a fair extent (similar to the inner wings on the 109). That and avoiding tip-stall would avoid possible wing-dropping related landing accidents, especially if not using counter-rotating propellers. (elliminating torq tends to improve stall characteristics too -the P-38 fared very well there)


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## Shortround6 (Mar 5, 2015)

Couple of points.



> And given the trouble the Taurus ended up having (and engineering commonality with the Hercules), that's unfortunate, but speculation for a separate thread. (and already came up in one of the recent engine threads)
> 
> That said, a medium altitude rated Perseus or Mercury would seem to fit well enough weight wise, likely slower due to drag though. (in the multi-role fighter-bomber and possible anti-shiping role it might have been better suited -and able to take more engine damage ... and stay in production after the Perigrine ceased)



The British, at least in the beginning of the war, considered engines with full throttle heights of around 13,000ft and up to be fully supercharged or high altitude engines, engines with full throttle heights of 3,500-8,000 were "medium" altitude. I know there is a gap there but they didn't seem to make any engines that fell in that gap. 

Taurus got a large part of it's power over the Perseus by turning higher rpm. 3300rpm vs 2600-2750rpm. You aren't going to be able to spin the Perseus much faster. A Perseus developed to equal a 1600hp Hercules is going to have around 1025-1030hp. Unfortunately that comes a little late. 

Any extra power _will_ be eaten by the extra drag, at least as far a speed goes. Unfortunately that also affects range. You may be able to fit fuel in where the radiators were but a higher drag airplane will burn more fuel even at cruising speeds. 

Again, slats _only_ begin to work when the angle of attack exceeds 12-13 degrees and don't show a lot of benefit until the angle of attack gets into the high teens. You either need a really high nose up attitude or a really steep glide path/approach angle. They can help but are not the miracles some people think they are. A number of designers used them in the 1930s (along with fixed or box slots) but general use declined for while.


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## stona (Mar 5, 2015)

Leading edge slats are effective in any situation where separation of the air flow around the leading edge may be a factor. They are effectively a type of boundary layer control device. The passive systems of the Whirlwind and Bf 109 were indeed only effective or activated at higher angles of attack. The principal effect of deployed slats is to increase the angle of attack for the stall by ensuring the continuation of the air flow about the airfoil. 
Cheers
Steve


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## kool kitty89 (Mar 6, 2015)

Hmm I wonder if the XF5F's performance is at all comparable to what a radial engined Whirlwind might have managed. Those R-1820s are pretty wide and (if the limited information on that plane is accurate) the XF5F was in a similar weight class, had a larger wing area, and managed an impressive speed way down at sea level. Albeit that was with 1,200 HP engines. (but 100 MPH faster than the F2A-2 using the same engine -I've never seen speed at altitude figures for the F5F, though ... if the SL figures are accurate, it should have been somewhere in the 420 MPH range at ~17,000 ft, though)

Of course, the radial engines suggested wouldn't be in that power output range ... at best you've got some Tauruses managing over 1100 hp down low. (admittedly with some gains due to the small diameter)

Level speed is still only one area to consider. Power to weight ratio, acceleration, rate of climb are all important.


Use of counter-rotating properllers might have had some input on the F5F's performance too. I'm not sure how many options there were for those among British engines.


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## Shortround6 (Mar 6, 2015)

Projected figures and actual figures for the XF5F show a wide discrepancy. The XF5F had some drag problems that were never resolved during the testing phase, like poorly fitting landing gear doors, that make it hard to say if a fully developed version would have come closer to the numbers. I believe there were also some cooling problems.

Speeds _may_ have been 358mph at 17,300ft and 312mph at sea level. 

Climb wasn't setting the world on fire either. 4.2 minutes to 10,000ft and 9.3 minutes to 20,000ft. Granted it Probably was done by the standard US procedure of using Military power for the first 5 minutes of the climb and then throttling back to "normal" (max continuous) for the rest of the climb. 

These numbers are for 178 US gallons on board. With 277 gallons speed drops about 1mph but climb takes over a minute longer to 20,000ft and service ceiling drops 1000ft.


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## kool kitty89 (Mar 7, 2015)

Shortround6 said:


> Speeds _may_ have been 358mph at 17,300ft and 312mph at sea level.


Ah, OK, that's much more belivable than the commonly sited figures I've seen. (more so since more modest performance would have made the cancellation less unreasonable too)


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## tomo pauk (Mar 7, 2015)

The X5F5 was good for 358 mph @ 17300 ft with 900 HP. sheet
That is without guns, ammo, not full tanks.


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## Trilisser (Jul 22, 2017)

A few belated comments:

1. I would be quite careful with Rubbra's memoirs as any sort of gospel. After all, he is extremely dismissive towarss direct fuel injection and turbocharging. Both areas in which R-R failed miserably. In the section dealing with the the Merlin's valve gear, he fails to admit that R-R screwed it royally by adopting those fixed cam followers, whose problems were never completely solved. V-1710, DB 600 srs and the Jumo 211/213 all used roller followers.

2. If Dowding dismissed the Whirlwind as a night-fighter for "high landing speed", he was incompetent as landing speed alone is meaningless in determining how easy an airplane is to land.

3. The idea that the Hurricane could do all the Whirly could do is obviously horseradish. The Hurricane is among the most overrated aircraft of WW2. E.g. Russian pilots disliked it s lot and Finnish Buffaloes made mincemeat of opposing Hurricanes. It was considered one of easiest opponents to shoot down.

4. A feasible alternative engine might have been the R-1820. If W-pedia is correct on the Peregrine's weight, the Cyclone did not weigh much more and gave 1200 hp on 100 octane at that time.

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## Trilisser (Jul 22, 2017)

About slats: slots could be also quite effective. Finnish VL designed slots for both the Fokker D.XXI and the Pyry trainer and the slots gave a significant improvement in stalling.


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## wuzak (Jul 22, 2017)

Trilisser said:


> A few belated comments:
> 
> 1. I would be quite careful with Rubbra's memoirs as any sort of gospel. After all, he is extremely dismissive towarss direct fuel injection and turbocharging. Both areas in which R-R failed miserably. In the section dealing with the the Merlin's valve gear, he fails to admit that R-R screwed it royally by adopting those fixed cam followers, whose problems were never completely solved. V-1710, DB 600 srs and the Jumo 211/213 all used roller followers.



Rolls-Royce did not fail with turbochargng.

They determined that it wasn't worth the weight and complexity.


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## fubar57 (Jul 22, 2017)

Trilisser said:


> 3. The idea that the Hurricane could do all the Whirly could do is obviously horseradish. The Hurricane is among the most overrated aircraft of WW2. E.g. Russian pilots disliked it s lot and Finnish Buffaloes made mincemeat of opposing Hurricanes. It was considered one of easiest opponents to shoot down.



On the other hand, Finland loved the 11 Hurricanes they received


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## GregP (Jul 23, 2017)

Another resounding spit decision. The Hurricane was either a great plane or else a bad one. 

Seems like it depends on who is talking at the time. I bet the BOB pilots would favor it, perhaps not for night fighting, though.


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## stona (Jul 23, 2017)

The Hurricane was more than adequate in 1940 which is essentially the period in question.

As far as comments about landing speeds for fighters to operate at night, I would suggest looking into the Air Ministry specifications and decisions of the Operational Requirements Committee before passing subjective comments on the AOC-in-C Fighter Command.

Cheers

Steve


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## pinsog (Jul 23, 2017)

tomo pauk said:


> The X5F5 was good for 358 mph @ 17300 ft with 900 HP. sheet
> That is without guns, ammo, not full tanks.



Old post, I know.

Tomo pauk: look at the weights on the XF5F. 7990 empty, 10,021 loaded with 178 gallons, 10,892 overload with 277 gallons.

The low back, bubble canopy XF5F had radio equipment installed. They installed the radio equipment when they rebuilt it from the high back, razorback, F4F looking fuselage it first had.

LOADED 10,021 minus empty weight 7990 leaves 2,031 for load, minus 1,112 for 178 gallons of fuel leaves 919, subtract 200 for pilot and 150 for oil leaves 569 pounds unaccounted for. I know they were never fitted, but I believe it was ballasted for 4 50's and some ammo during tests. 4 50's would be 300 pounds, 200 rounds per gun would be 200 pounds, leaving 69 pounds for miscellaneous things I missed.

OVERLOAD 10,892 minus empty weight 7,990 leaves 2,902 for load, minus 1,731 for 277 gallons of fuel leaves 1,171, subtract 200 for pilot and 200 for overload oil, leaves 771, subtract 300 pounds for 4 50's, leaving 471, subtract 400 pounds for 400 rounds per gun, leaving 71 pounds for miscellaneous things I missed.

I believe this makes a good case for the XF5F being ballasted for weapons during these tests.

Also, the climb rate on that test doesn't look right to me. The climb rate of this plane was supposedly 4,000 fpm. At 10,000 pounds with 1,800 to 2,400 hp divided between 2 3 bladed props, that sounds very reasonable.

Also, what hp would a Wright 1820 that's rated at 900 hp at 14,000 feet be down to at 17,300 feet?


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## Trilisser (Jul 23, 2017)

fubar57 said:


> On the other hand, Finland loved the 11 Hurricanes they received



No, they did not.


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## Trilisser (Jul 23, 2017)

wuzak said:


> Rolls-Royce did not fail with turbochargng.
> 
> They determined that it wasn't worth the weight and complexity.



That is the R-R way to save face.


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## Trilisser (Jul 23, 2017)

stona said:


> As far as comments about landing speeds for fighters to operate at night, I would suggest looking into the Air Ministry specifications and decisions of the Operational Requirements Committee before passing subjective comments on the AOC-in-C Fighter Command.
> 
> Cheers
> 
> Steve



All pilot accounts I have read suggest the Whirly could operate from smaller fields than the Spit, e.g.


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## fubar57 (Jul 23, 2017)

Trilisser said:


> No, they did not.

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## herman1rg (Jul 23, 2017)

Battle of Britain in Detail Part 5

Numbers of RAF fighters listed just under the picture of Sir Hugh Dowding,


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## stona (Jul 23, 2017)

Trilisser said:


> All pilot accounts I have read suggest the Whirly could operate from smaller fields than the Spit, e.g.



I'd have to look up the Whirlwind's operational take off run,but the requirement to which it was built required it to clear a 50' screen at 600 yards, though this might be extended to 700 yards in certain circumstances.
Spitfire I, N3171, was tested by the A&AEE, clearing a 50' screen at 370 yards with a Rotol propeller.
Cheers
Steve


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## herman1rg (Jul 23, 2017)

A total of 1,715 Hurricanes flew with Fighter Command during the period of the Battle, far in excess of all other British fighters combined. Having entered service a year before the Spitfire, the Hurricane was "half-a-generation" older, and was markedly inferior in terms of speed and climb. However, the Hurricane was a robust, manoeuvrable aircraft capable of sustaining fearsome combat damage before write-off; and unlike the Spitfire, it was a wholly operational, go-anywhere do-anything fighter by July 1940. It is estimated that its pilots were credited with four-fifths of all enemy aircraft destroyed in the period July-October 1940.

From the RAF website

So it wasn't that bad really....................

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## fubar57 (Jul 23, 2017)

Just read an article saying the Hurricanes arrived too late for the Continuation war but did shoot down 5 aircraft later on with loss


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## stona (Jul 23, 2017)

In what the British call the BoB period there were, on average, 34 Hurricane squadrons and 19 Spitfire squadrons operational.

Based on the totals (which are debatable) of 655 victories credited to 30 Hurricane squadrons (22.5 per squadron) and 530 victories credited to 19 Spitfire squadrons (28 per squadron) we can see the difference was not that great.

The same figures give the Hurricane squadrons 55% and the Spitfire squadrons 43% of the kills.

Cheers

Steve


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## pbehn (Jul 23, 2017)

herman1rg said:


> A total of 1,715 Hurricanes flew with Fighter Command during the period of the Battle, far in excess of all other British fighters combined. Having entered service a year before the Spitfire, the Hurricane was "half-a-generation" older,


.
.



stona said:


> In what the British call the BoB period there were, on average, 34 Hurricane squadrons and 19 Spitfire squadrons operational.
> Based on the totals (which are debatable) of 655 victories credited to 30 Hurricane squadrons (22.5 per squadron) and 530 victories credited to 19 Spitfire squadrons (28 per squadron) we can see the difference was not that great.
> 
> The same figures give the Hurricane squadrons 55% and the Spitfire squadrons 43% of the kills.



At the end of the Battle of France, there were approximately 250 each of Spitfire and Hurricanes. Without the Hurricane the training units and squadrons withdrawn and rebuilding away from the south east would have had nothing to fly.


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## Greyman (Jul 23, 2017)

It depends on how you work the variables (boosts, weights, mods, variants, etc.), but looking at the figures - generally the Spitfire has the longer take off run (no take off flaps) but the Whirlwind has the longer landing distance (higher speed, less effective brakes).


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## wuzak (Jul 23, 2017)

Trilisser said:


> That is the R-R way to save face.



From a decision they made in 1929 after testing a turbo Condor?


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## Trilisser (Jul 23, 2017)

fubar57 said:


> View attachment 378796​


Source for that horseradish? E.g. the serviceability of the Hurricane in Finnish service was very low due to lack of spares and relative fragikity of the early model Merlins used in Finnish Hurries.


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## Trilisser (Jul 23, 2017)

wuzak said:


> From a decision they made in 1929 after testing a turbo Condor?


I have read most Merlin-related RRHT books and the tone in them is very clear: all technical choices R-R made were the best and if some other maker selected another solution, like direct injection or turbocharging, the authors are extremely arrogantly dismissive. In the RRHT book on the Meteor one can read R-R memos fighting to the last breath against diesel engines in tanks hailing the spark-ignition engine as the best possible tank engine ever. One just needs to look at modern tank fleets and their powerplants to weigh how far-sighted R-R was. That ignorance is even more perverted when the existence of the Soviet V-2 diesel was known. The V-2 had over 30 % better s.f.c. over the r.p.m. that the fuel crematorium Meteor.


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## fubar57 (Jul 23, 2017)

"Hawker Hurricane Mk.I-V" by Martyn Chorlton - 2013


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## Trilisser (Jul 23, 2017)

Thanks! One more reason to avoid that Chorlton. Uuno Karhumäki, a very experienced Finnish pilot and aviation pioneer, described the Hurricane's handling "as if every control was operated via rubber bands". On average Finnish Hurris accumulated 101 flying hours (Buffaloes averaging 448 hrs). Even Gladiators averaged over 170 hrs. And Russian interrogated PoWs described it "somewhat weird". All this from the book Lentäjän näkökulma 2.


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## Greyman (Jul 23, 2017)

Mason had this to say in his Hurricane book:

_... despite a complete absence of spare parts, most survived to see operational service in the Continuation War ... They were employed principally for interception duties owing to their lack of range, but are generally remembered by the Finnish pilots with affection, who judged them to be their best fighters until the arrival of new German aircraft. They gained a number of victories over Soviet aircraft in the early months of that war and none was ever lost in air combat._

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## Trilisser (Jul 24, 2017)

stona said:


> I'd have to look up the Whirlwind's operational take off run,but the requirement to which it was built required it to clear a 50' screen at 600 yards, though this might be extended to 700 yards in certain circumstances.
> Spitfire I, N3171, was tested by the A&AEE, clearing a 50' screen at 370 yards with a Rotol propeller.
> Cheers
> Steve


In early 1985 Aeroplane Monthly ran a 2-part article on the Whirlwind. It quotes some test data, giving a TO ground of 325 yds at +9 boost. The article received reader feedback and J. B. Wray, former pilot from the 137. Sqn., wrote:"...allowed an experienced pilot to land in a shorter distance than either the Spitfire or Hurricane."


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## Trilisser (Jul 24, 2017)

Greyman said:


> Mason had this to say in his Hurricane book:
> 
> _... despite a complete absence of spare parts, most survived to see operational service in the Continuation War ... They were employed principally for interception duties owing to their lack of range, but are generally remembered by the Finnish pilots with affection, who judged them to be their best fighters until the arrival of new German aircraft. They gained a number of victories over Soviet aircraft in the early months of that war and none was ever lost in air combat._



Where on Earth did Mason get that fertilizer? Not a single Finnish source supports Mason or Chorlton.


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## Shortround6 (Jul 24, 2017)

Trilisser said:


> That is the R-R way to save face.




The truth is probably somewhere in the middle. 

You seem to do a lot of Rolls Royce bashing but a look at some Facts by Rolls Royce shows that a Hurricane II at 30,000ft was getting 778hp to the prop. it was getting 89hp from exhaust thrust. The power from thrust varies with the speed so while climbing the actual power is less. 
Now I would say that over 80 extra hp (and peak of 126hp) anywhere from 15,000ft to over 30,000ft for the investment of 30-40 lbs of manifold is a pretty good return. 

Blaming RR for NOT building turbos is also a bit harsh. P&W, Wright and Allison never built a turbo than went on a production engine. What they did in an experimantal shop I have no idea but they probably had more work than they could handle to fool around much with their own turbos (they did work on their own compressors) 

ALL US turbos came from General Electric. 

General Electric also could NOT build turbos in mass production until the casting of the turbine blades was worked out. This happened, just about in the nick of time, when someone ( I forget who but he was famous in engine circles) noted that the the materials in turbine blades was very close to the materials used in some dentures/false teeth and that by using the technology the dental industry used precision castings of the blades could be done.

Everybody praises the German direct fuel injection but few want to actually consider it's faults. 
1. RR got a drop of 25 degrees C in the intake due to the fuel vaporization in the supercharger and manifolds. This allowed for slightly higher boost pressure to be used.
2. The German fuel injection _as used _did not allow for running extra rich and using the extra fuel as coolant allowing for higher boost.
3. The German fuel injection _as used _did not allow fro running extra _lean _and allow for long range flights in non-combat environments. 
4. The German fuel injection used many more parts than the British carburetors. RR did not make their own carbs, they bought them form an outside vendor, so did the American engine makers. 
Who was going to make the direct Fuel injection systems for the British and _what else was NOT going to get made?
_
Perhaps RR glosses over the last part a bit easily but it is a very real concern to the British. 

I would also bet a bit more careful in comparing the RR Meteor to diesel tank engines. Yes the British held onto it for too long but comparing a 1943 engine to 1950/60 diesels doesn't paint a fair picture either. The US for all it's industrial power, didn't switch to diesels in it's medium tanks until the late 50s and was still running gas engines in the older models into the 60s. 

Once you have a power pack for a tank you have to be careful about changing it. Taking out a 2400rpm engine and replacing it with an 1800rpm engine for instance, even of the same horse power, will lower the top speed in each gear by 25% unless you change the final drive ratios. If you change the final drive ratios hopefully the new engine makes similar torque once multiplied by the gear ratios.

It also helps if the existing gear box/steering gear hand handle the power of the new engine. Otherwise you are replacing everything at a much greater cost. And that brings us to a final point.

RR was in business to make money, They were going to build what the customer wanted/would pay for. If RR offered and improvement but it was costly the customer (British Government?) might decide to keep the old engine or arrangement.

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## stona (Jul 24, 2017)

Shortround6 said:


> RR was in business to make money, They were going to build what the customer wanted/would pay for. If RR offered and improvement but it was costly the customer (British Government?) might decide to keep the old engine or arrangement.



The British government, in the shape of the Air Ministry, was the only customer for Rolls Royce aero engines in the 1930s. In 1930 Rolls Royce produced 122 engines and initial expansion, to 1,182 in 1935, was based entirely on the Kestrel and almost exclusively for the Air Ministry.

By the time that Scheme L was approved in April 1938 Rolls Royce had spent about £750,000 of its own money on rearmament. When the company failed to find an alternative site for its motor car division in Derby a new factory for aero engines in Crewe was suggested, but the company did not feel that it could pay for it. Financial liability for the Crewe factory was accepted by the Air Ministry, which is close to nationalisation without calling it that.

Cheers

Steve

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## Greyman (Jul 24, 2017)

Trilisser said:


> "...allowed an experienced pilot to land in a shorter distance than either the Spitfire or Hurricane."



Going out on a limb - I'd hazard a guess they found a way around the criticisms the A&AEE had on the Whirlwind's landing:

2.7 Landing. The landing is unsatisfactory. The tail cannot be brought down for a three-point landing although the control column is fully back much before the normal "flattening out" period is completed. The aeroplane lands heavily on its front wheels, and bounds along, and thus full use of the breaks cannot be made for the first part of the landing run.

The men flying and maintaining their Whirlwinds (for years) _really _got their rides down to a science to an impressive extent. I think it would be a mistake to cater only to what experienced pilots could do with the aircraft.


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## Greyman (Jul 24, 2017)

Trilisser said:


> Where on Earth did Mason get that fertilizer? Not a single Finnish source supports Mason or Chorlton.



Do you have any other information on this aside from a single Finnish veteran letting us know the Hurricane control response wasn't flawless? That said - why do I get the impression that any positive feedback the Finnish pilots had on the Hurrie will be swept under the rug ...

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## stona (Jul 25, 2017)

Greyman said:


> Going out on a limb - I'd hazard a guess they found a way around the criticisms the A&AEE had on the Whirlwind's landing:



One of the many problems that plagued the type was tail wheel failures (at least until a new oleo was introduced). Pure conjecture, but given the A&AEE report, maybe that was due to something the pilots were doing to get the tail down.

Incidentally, Harris did not share the RAF/Air Ministry conviction that a low landing speed was required for aircraft operating at night and disagreed with Dowding on this issue. He thought that the Whirlwind might make a decent stop gap night fighter, but at a time when nobody really knew what a night fighter should be.

_"...I have never yet met an aircraft that can be safely flown by day that cannot be safely and easily flown by night, once the pilots can night fly properly on any type."_

This did NOT reflect RAF doctrine of the time, which was more accurately reflected by Dowding's view. Harris was never one for toeing any line, and almost always said what he thought, so it is hardly surprising to find him at odds with official policy.

Cheers

Steve


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## pbehn (Jul 25, 2017)

Isnt there a difference between a night time landing and a night time landing at war?


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## Trilisser (Jul 25, 2017)

SR6: 

1. I am not bashing R-R per se, but I just find it interesting that e.g. Maybach, who had basically monopoly on tank engines in Germany, defended its petrol engines with thetoric very similar to R-R's. This despite that by that time the Russian V-2 was being applauded by German tank experts.

Just like in German literature it is fashionable to bash turbocharging exactly like R-R folks do. So is it a coincidence that representatives of nations (German, British) that failed to bring turbochargers to wider service use are so keen to bash thr technology, just like British and Americans failing to introduce direct injection tend to bash it.

2. As for the negative aspects of direct injection, it might be worth noting that Russians adopted it for the Ash-82 and the most powerful models of the Mitsubishi Kinsei had direct injection too.

I agree that the available data suggests that for long-range cruising German engines are at a disadvantage. However, is that caused by the fuel system as such? As far as I know, even the carburettor-fueled Argus engines did not allow for manual leaning. 

As for the "boost boosting" via overrich mixture, the BMW 801 at least ran pretty rich at Notleistung, though nowhere as rich as American radials. And frankly, I consider ADI a much more refined way to do it.


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## Trilisser (Jul 25, 2017)

Greyman said:


> Do you have any other information on this aside from a single Finnish veteran letting us know the Hurricane control response wasn't flawless? That said - why do I get the impression that any positive feedback the Finnish pilots had on the Hurrie will be swept under the rug ...



The problem is that finding that data would probably require digging in the archives. The most authoritative published book dealing with Finnish experiences of various wartime fighters is Jukka Raunio's Lentäjän näkökulma 2. Raunio is an aircraft engineer (Dipl. Ing.) by profession. And that book does not hail the HC like Brits do. It was, however, found to be an easy aircraft to fly. But not on par with the Curtiss Hawk or the Buffalo.

Some information could be found in HC pilots' combat reports, but again that would need archival digging: many combat reports have been published in Kari Stenman's books, but for some reason Herr Stenman's policy has been to publish only the combat narrative section and leave out the section dealing with enemy and technical observations. 

To put things into perspective:

-11 Finnish Hurricane averaged 101 hours and claimed a total of 5.5 victories
-30 Gladiators averaged 177 hours with a total of 38 claims; most GL use was recce
-Fokker D.XXI achieved 187 claims averaging 345 hours
-and the most difficult FAF fighter to keep flying, the Fiat G.50 (35 of them) achieved 99 claims while averaging 233 hours


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## fubar57 (Jul 25, 2017)

Start digging then....lay the proof on us, that's what we are here for. You are giving us one man's opinion

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## stona (Jul 25, 2017)

pbehn said:


> Isnt there a difference between a night time landing and a night time landing at war?



Black out.

A certain Group Captain A T Harris was Deputy Director of Operations and Intelligence in 1934, and it was he who drew the attention of the Chiefs of the Air Staff to the lack of 'modern' features like retractable undercarriage, enclosed cockpits and landing flaps on many designs being submitted in October of that year. He was well aware of the advantages that such devices could provide. 

Cheers

Steve


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## Trilisser (Jul 25, 2017)

fubar57 said:


> Start digging then....lay the proof on us, that's what we are here for. You are giving us one man's opinion


Hah! If you pay me all the expenses incurred, then ok. Just to please you I won't drive 1100 km, won't pay hotel bills etc.


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## Trilisser (Jul 25, 2017)

fubar57 said:


> Start digging then....lay the proof on us, that's what we are here for. You are giving us one man's opinion



If you pay all the expenses incurred, fine. The archives are 500 km from me, and I won't pay one cent just to satisfy your curiosity.


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## Trilisser (Jul 25, 2017)

stona said:


> Black out.
> 
> A certain Group Captain A T Harris was Deputy Director of Operations and Intelligence in 1934, and it was he who drew the attention of the Chiefs of the Air Staff to the lack of 'modern' features like retractable undercarriage, enclosed cockpits and landing flaps on many designs being submitted in October of that year. He was well aware of the advantages that such devices could provide.
> 
> ...


Who is atharris? I know an A. T. Harris, but atharris I don't.


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## fubar57 (Jul 25, 2017)

Trilisser said:


> Where on Earth did Mason get that fertilizer? Not a single Finnish source supports Mason or Chorlton.



LMAO...you say this fertilizer yet you don't have sources to support it. Just because you are from Finland does not automatically make you correct. Sources or it didn't happen

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## stona (Jul 25, 2017)

Trilisser said:


> Who is atharris? I know an A. T. Harris, but atharris I don't.



WTF are you reading the posts on? In both my post and quote in your reply it is clearly A T Harris.

Cheers

Steve


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## ChrisMcD (Jul 25, 2017)

Shortround6 said:


> The truth is probably somewhere in the middle.
> 
> Blaming RR for NOT building turbos is also a bit harsh. P&W, Wright and Allison never built a turbo than went on a production engine. What they did in an experimental shop I have no idea but they probably had more work than they could handle to fool around much with their own turbos (they did work on their own compressors)
> 
> ALL US turbos came from General Electric.



Sanford Moss at GE seems to have perfected the turbocharger almost single handed.

Supercharger Development in the U.S. During the Inter-War Period

Both Bristol and RR had developed turbocharged engines, but they were clearly not up to mass production. And yes I do think it was the metallurgy that defeated them.

Rolls do seem to have had considerable expertise with heavy duty gear sets - both in supercharger drives and propellor reduction gears, so it is reasonable for them to have played to their own strengths. And yes they seem almost as good as Lockheed in persuading everyone else that their way is the best way


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## ChrisMcD (Jul 25, 2017)

For another view on the Whirlwinds handling - how about Winkle Brown in "Wings of the Weird and Wonderful".

"All in all the Whirlwind could be said to be a contradiction of the dictum that 'if it looks good it should fly good'. Certainly I was profoundly disappointed with its handling qualities in all but single-engine flying. 

The manoeuvrability of the Whirlwind was brought into question by the tendency to buffet badly in tight turns, and with a wing loading of 40lb/sq ft (195kg/m2) this was a crippling restriction. Also in dives from 25,000ft (7,620m) above 350mph (563km/h) a longitudinal pitching set in. If speed was allowed to increase there was a distinct loss of elevator effectiveness at 400mph (644km/h) at 15,000ft (4,572m) and a very strong pull force was required for recovery. These characteristics made the Whirlwind a poor bet as a fighter, so it was given a fighter-bomber role in service and and proved less than effective in that form. 

The aircraft was not easy to land because speed had to be kept up to provide sufficient elevator control for hold-off. This therefore gave a long run-out - not the best characteristics for all weather operations."

Winkle makes clear that he wanted to like the Whirlwind, but was disappointed. His comments do explain why it was not used as a fighter, post BoB and why it was restricted to the number of airfields it could use.


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## Ascent (Jul 25, 2017)

I think castigating RR for not developing diesel tank engines is one of the sillier things I've seen on here. They didn't set out to design tank engines at all, they were in the business of building aero engines. The fact that the Merlin made a decent engine for a tank in the form of the Meteor was just a happy chance.

Why not have a go at them for not developing speed boat engines, it makes as much sense, or criticise Wright for not developing diesel tank engines.


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## Shortround6 (Jul 25, 2017)

ChrisMcD said:


> Sanford Moss at GE seems to have perfected the turbocharger almost single handed.



Aside from the 50 P-30s there were over 40 US aircraft equipped with turbochargers before 1940. So the US Army was at least putting a trickle of money into them for over 10 years, the P-30 being far from the first US fighters with turbos although the most numerous until the P-38. 









The US army wanted turbos, it was willing to pay for turbos in small numbers over a period of years, It was promising to buy turbos in quantity once they were sorted out. 

The British air ministry was doing none of those things so Rolls Royces "failure" to develop the turbo at their own expense needs reassessment.

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## Shortround6 (Jul 25, 2017)

Ascent said:


> I think castigating RR for not developing diesel tank engines is one of the sillier things I've seen on here. They didn't set out to design tank engines at all, they were in the business of building aero engines. The fact that the Merlin made a decent engine for a tank in the form of the Meteor was just a happy chance.
> 
> Why not have a go at them for not developing speed boat engines, it makes as much sense, or criticise Wright for not developing diesel tank engines.



Well. actually RR did develop a speed boat engine, sort of. A few fast craft were equipped with a marine Merlin but the idea went nowhere when they figured out that they needed all the Merlins they could get for aircraft. 
Wright didn't develop tank tank engines but the Guiberson company did use Wright engines as a basis for several different tank engines.


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## stona (Jul 25, 2017)

Anyone know how many launches/MTBs were Rolls Royce powered? I seem to remember that some were powered by American V-12 petrol engines, but I could be wrong, this is not really my thing.
Cheers
Steve


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## Shortround6 (Jul 25, 2017)

I have seen a number of "70" marine Merlins supplied but at 2 or 3 engines per boat and some engines held as spares I have no idea how many boats were actually Melrin powered. 
I believe it was _after_ they decided to not use Merlins that they tried to use Issota-Fraschini engines. 
The Vast majority of British small fast craft were powered by American engines. Packard supplied thousands of V-2500 marine engines for Vosper and Thornycroft boats and Fairmile Ds 
The Fairmile A, B and Cs were powered by American Hall-Scott engines.

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## Ascent (Jul 25, 2017)

Shortround6 said:


> Well. actually RR did develop a speed boat engine, sort of. A few fast craft were equipped with a marine Merlin but the idea went nowhere when they figured out that they needed all the Merlins they could get for aircraft.
> Wright didn't develop tank tank engines but the Guiberson company did use Wright engines as a basis for several different tank engines.



That was kind of my point. And the Wright R974 was used to power thousands of M4 and M4A1 Sherman's. The engines were used because they were available and filled a need, they weren't created specifically for those tasks.


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## rochie (Jul 25, 2017)

Trilisser said:


> A few belated comments:
> 
> 1. I would be quite careful with Rubbra's memoirs as any sort of gospel. After all, he is extremely dismissive towarss direct fuel injection and turbocharging. Both areas in which R-R failed miserably. In the section dealing with the the Merlin's valve gear, he fails to admit that R-R screwed it royally by adopting those fixed cam followers, whose problems were never completely solved. V-1710, DB 600 srs and the Jumo 211/213 all used roller followers.
> 
> ...

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## tomo pauk (Jul 27, 2017)

Shortround6 said:


> ...
> Everybody praises the German direct fuel injection but few want to actually consider it's faults.
> 1. RR got a drop of 25 degrees C in the intake due to the fuel vaporization in the supercharger and manifolds. This allowed for slightly higher boost pressure to be used.
> 2. The German fuel injection _as used _did not allow for running extra rich and using the extra fuel as coolant allowing for higher boost.
> ...



1 and 4: people rarely mention that big/powerful V12s with single carb, like the Merlin and V-1710, needed backfire screens installed before cylinders, meaning a loss of rated altitude vs. an engine that does not have backfire screens. Eg. on the V-1710 difference was 1000 ft at 1-stage engines, 1500 ft on turboed. RR (and some other engine manufacturers, not just from the UK) purchased bad carbs - switch to the 'fuel pump' type ('pressure injection' as the called it acros the pond) gained 8-10 mph for the Spitfire V, plus 1500 ft worth of ceiling. Fuel pumps were installed after half of the war passed. Further, the bad type of carb meant that ice guard is needed for really hi-alt flying, again an 8 mph loss.
Granted, carbs were far simpler things.
2. BMW 801D certainly used extra-rich fuel mixture as a mean for cooling the engine when extra boost for more power was needed, managing 1900-2000 HP in low gear from mid 1943 on (before they swithched to a simpler system).

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## Shortround6 (Jul 27, 2017)

The Men at RR figured that a 25 degree C drop in intake temperature was good for about a 10% increase in gas flow through the supercharger. It changed the compression ratio of the supercharger from a theoretical 2 to 1 to 2.12 to . 

This was at sea level at temperatures between 0 and 15 degrees C to begin with. It was also with "fresh" gasoline. 
Old gasoline often has some of the most volatile components already evaporate out. Or "fresh" gasoline held in the aircraft tanks on a hot day. 

As the intake temperatures fall with increased altitude the rate or effect of vaporization also falls, until 0 vaporization occurs at temperatures between -20 degrees C and -40degrees C however this is counteracted to some extent by the lower air pressure. The 0 evaporation temps being for a pressure of 760mm. lowering the air pressure to 300mm ( a bit over 23,000ft) lowers the 0 vaporization point about another 18 degrees C.

For practical estimates a drop of 20 degrees C can be used (8% increase in mass flow?) up to 20,000ft with the 20 degree drop being an overestimate at higher altitudes. 

Numbers are from the Rolls-Royce Heritage Trust book "The Performance of a Supercharged Aero Engine" by Stanley Hooker, Harry Reed and Alan Yorker. Much of this section of the book (pages 33-34) is based on a paper by Oscar C. Bridgeman "The Equilibrium Volatility of Motor Fuels from the standpoint of their use in Internal Combustion Engines." from 1934. 

It should be noted that this evaporation is for the fuel _*before* _it reaches the eye of the supercharger. Once it has been subject the to the temperature rise in the supercharger the temperature of the mixture entering the intake manifold/s is subject to the full 25 degrees C drop.

Please note that a Merlin XX engine has a temperature rise at full throttle of 145 degrees C through the supercharger. 

I would also note that the Allison, P & W , Wright and Bristol engines (and many others) also got a similar "boost" from fuel evaporation.

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## herman1rg (Jul 28, 2017)

Great piece of information


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## tomo pauk (Jul 28, 2017)

Shortround6 said:


> The Men at RR figured that a 25 degree C drop in intake temperature was good for about a 10% increase in gas flow through the supercharger. It changed the compression ratio of the supercharger from a theoretical 2 to 1 to 2.12 to .
> ...
> Numbers are from the Rolls-Royce Heritage Trust book "The Performance of a Supercharged Aero Engine" by Stanley Hooker, Harry Reed and Alan Yorker. Much of this section of the book (pages 33-34) is based on a paper by Oscar C. Bridgeman "The Equilibrium Volatility of Motor Fuels from the standpoint of their use in Internal Combustion Engines." from 1934.
> ...
> ...



Thank you for the detailed post.
Re. RRHT book, I do have a few questions, not that I'm saying youre obliged to find answers to them willy-nilly. Like - is i clear from the book how much a performance penalty represented the installation of the float-type carb on, say, Merlin, vs. pressure injection ('fuel pump')? Any carb vs. no carb at all? In 'no ram' condition as well as with ram air? Is it clear how much the flame traps ('backfire screens' in US parlance) were a detriment to the rated height? How much did a necessity to have some sort of heating of the carb was involving how a big turbulence of the airflow through a carb? Was there any benefit from fuel evaporation in the cylinders of a direct-injected engine? Fuel consumption differences?


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## Shortround6 (Jul 28, 2017)

The book is pretty much concerned with the Merlin XX engine and in fact seems to be a reprint of a book or papers first published in 1941 so many of your questions do not apply. 
It has a lot of formulas and charts and _seems _to be a handbook for RR (or allied?) engine designers on what they had accomplished up until then with a lot of comparisons between theory and test flight results. 
The section on ejector exhaust manifolds for example starts on Page 16 and runs to the end of Page 22 but there are some full page charts in there. 

Please remember the one of Hookers claims to fame was realizing that some of the formulas that were in text books on supercharger design were wrong. Getting useful formulas that were backed up by flight testing was a good step in the advancement of supercharger design. 

There is a short section on the effects of forward facing air intakes.


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## tomo pauk (Jul 29, 2017)

Thank you again.
Basically - instead of naming the book, say, "1934-1941, design practies at Rolls Royce V12 aero engines department", someone named it "The Performance of a Supercharged Aero Engine" - not just as if radial and diesel engines don't exist, but no one else in the world is/was designing aero engines?


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## Shortround6 (Jul 29, 2017)

To be charitable one might look at the title "The Performance of *a* Supercharged Aero Engine" as being about one particular supercharged aero engine and not a compendium of ALL supercharged aero engines. Most of which the engineers at Rolls Royce had little or no first hand knowledge of in 1941. 
I have no idea how much distribution the book actually had at the time but most companies were not going out of their way to share their research and development with their competitors. 

There are charts showing results of calculations in comparison to flight test results and differences between RR flight tests and flight tests by Hawker Aircraft. Or differences between ground tests and flight tests to see the variations (check on theory).

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## ChrisMcD (Jul 31, 2017)

tomo pauk said:


> Thank you for the detailed post.
> Re. RRHT book, I do have a few questions, not that I'm saying youre obliged to find answers to them willy-nilly. Like - is i clear from the book how much a performance penalty represented the installation of the float-type carb on, say, Merlin, vs. pressure injection ('fuel pump')? Any carb vs. no carb at all? In 'no ram' condition as well as with ram air? Is it clear how much the flame traps ('backfire screens' in US parlance) were a detriment to the rated height? How much did a necessity to have some sort of heating of the carb was involving how a big turbulence of the airflow through a carb? Was there any benefit from fuel evaporation in the cylinders of a direct-injected engine? Fuel consumption differences?



As a slight digression, have you come across Rod Banks' work sorting out the Fiat engine on the Schneider Trophy Macchi-Castoldi M.C.72?

Macchi Aeronautica Archives - This Day in Aviation

Shows the lethal effects of backfires when the ram effect was not taken into account!

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## stona (Aug 2, 2017)

1938 A&AEE report gives the landing run for the Whirlwind as 635 yards, well within the capabilities of airfields of the time.

It was not the safest aircraft to fly. According to the two relevant squadron ORBs 132 pilots flew the Whirlwind operationally, and 46 were killed.

The conversion to fighter bomber was not always popular either. Unofficial, that is before A&AEE, tests were carried out by F/L Rudland on 12th August 1942, who described the loss in speed and various other factors caused by the bombs before promptly putting in for a transfer, concluding with the words

_"If I had wanted to drop bombs I would have flown a Lancaster." 
_
As far as the engines go, when the first Peregrines were delivered in February 1940 the decision had already been taken to limit production to 290 units, barely enough for the 114 Whirlwinds built, so it did die with its engines. There was never a serious effort to re-engine the aircraft, despite Petters letter to Leigh-Mallory, who had little influence on which aircraft the Air Ministry/MAP produced anyway.

Cheers

Steve

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## Shortround6 (Aug 2, 2017)

The safety would have to be put into context. Like pick another two squadrons operating similar missions in the same area and compare losses for a similar period of time.
Some pilots thought they stood a better chance in crash landing in the Whirlwind as the engines/nacelles usually hit first and took a fair amount of the impact, without coming back into the cockpit like some single engine fighters.
Some pilots made it back due the twin engines. Some may not have made it back due the twin engines, poor engine controls, lack of feathering propellers and cross over fuel systems.

Low altitude strafing/bombing missions are usually high risk.

Some fighter pilots only want to fight other aircraft.

I would also note that the bomb racks on the Whirlwind were pretty basic,




Compared to the racks + fairings fitted to Typhoons, Tempests




Hurricanes




Wartime reporting being less than accurate


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## Old Wizard (Aug 2, 2017)




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## stona (Aug 3, 2017)

Shortround6 said:


> I would also note that the bomb racks on the Whirlwind were pretty basic,



They were also time consuming to retro fit, the entire outer wing section had to be removed.
Why waste time developing a special fairing for an aircraft operated by two, usually under strength, squadrons?



Shortround6 said:


> Low altitude strafing/bombing missions are usually high risk.



17 of the 46 were killed in flying accidents, not in action.

For this the two squadrons claimed 13 enemy aircraft destroyed and 18 damaged, though one was a Blenheim of 1401 Meteorological Flight and doesn't count. That is no reflection on the Whirlwind squadrons, these things happened unfortunately, probably more than we'll ever know.

Cheers

Steve


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## stona (Aug 3, 2017)

Tactics for making bombing attacks on shipping: It took a lot of aircraft to protect the actual fighter bombers.

OUTWARD FORMATION - ANTI FLAK FIGHTERS

Anti-flak fighters leading, in Flights line abreast, with aircraft line abreast 1,200 yds between Flights, 50 yds between aircraft, &100 feet above sea-level.

BOMBERS

In sections line abreast 50 feet above sea-level & 400 yds behind the anti-flak fighters.#2s in each section flying two spans out and one length behind their #1s. In this formation, the leaders are in the best position to choose the targets. If eight aircraft are used, repeat the formation for four aircraft, Flights astern.

ATTACKING

Fuse bombs & put both selector switches to the 'on position immediately on setting course.
Swing into the best position on sighting enemy (1.e. abeam or up sun). It is better to spend two minutes doing this than to attack without thought immediately on sighting. In the formation given above, each section of bombers will be able to follow the corresponding anti-flak Flight onto target.
Time your attack so that you are about on target as the anti-flak fighters break away. If both you and the Spit boys have your finger out, the last anti-flak cannon shell should beat your bombs to the target by a short head. In this way, less flak will be experienced as often the fighters draw the ships' fire.
Concentrate on your bombing run, make this absolutely on the deck. Fly straight at your ship, and plant your bombs on the waterline.
Keep your camera button pressed on your run in so that you can prove to the Intelligence Officer that it was a 4,000 tonner, not a 150 ton coaster. Most Intelligence Officers have never heard of a ship of more than 1,000 tons anyway, and you will be able to say, 'I told you so', when the combat film comes back.
Do not jink, it serves no purpose and only spoils your aim.
Do not fire your cannon, it is nice to hear the noise, but you cannot do both jobs at once, and will only make a cock of both. Leave anti-flak to the Spits.
Both aircraft in a section must attack the same ship. Better one ship at the bottom than two damaged.
Both aircraft should pass over the ship practically together. In this way the early demise of the #2, who might otherwise be blown up by his leader's bombs, will be avoided.
After bombing, pull over the masts (recommended) & get down on the deck again. DO NOT career wildly over the sky under the impression you are taking evasive action.This only makes everyone's job, particularly the escort, more difficult.
Keep Station. The leader will throttle back immediately after leaving the target area to make this easier.
If attacking at night you will naturally attack into the moon. Bank sharply, right or left, keeping ow, immediately after. If you keep straight on you will make a nice target silhouetted against the moon.

REMEMBER - FLAK LOOKS A LOT WORSE THAN IT IS

RETURNING HOME

Bomber leading, Sections line abreast, & 100 - 150 yds apart. The #2s 100 yds behind and 100 feet above their #1s.
Anti-flak will escort, the former escort giving rear cover.
Defuse Selector switches to 'off' before crossing the coast.
Do not shoot a line to the Intelligence Officer about the size of the ship. An M-Class minesweeper looks like a destroyer. A destroyer looks like the Scharnhorst. Be modest, halve your estimate of tonnage, & wait until your camera films have been developed.

Cheers

Steve

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## Shortround6 (Aug 3, 2017)

stona said:


> They were also time consuming to retro fit, the entire outer wing section had to be removed.
> Why waste time developing a special fairing for an aircraft operated by two, usually under strength, squadrons?



I agree with the 2nd, but then don't complain or use the lower performance as a strike against the Whirlwind. 





> 17 of the 46 were killed in flying accidents, not in action.
> 
> For this the two squadrons claimed 13 enemy aircraft destroyed and 18 damaged, though one was a Blenheim of 1401 Meteorological Flight and doesn't count. That is no reflection on the Whirlwind squadrons, these things happened unfortunately, probably more than we'll ever know.



How many pilots were lost in flying accidents by the first two Typhoon squadrons over a similar span of time? 

Or even Hurricane squadrons?

17 pilots lost due to accidents is still 17 too many but it took another 10-15 years for flight safety to really become an important part of ANY air forces culture. 

Using enemy aircraft destroyed as a measure of a strike fighters success seems a bit biased. How many Railroad wagons and locomotives were shot up even before the bombs arrived, How many coastal craft? Other assorted ground targets? A few mission were against distilleries, what 20mm shells were going to do against a distillery I have no idea but they were among the targets ordered from on high. 
One also has has to ask how many Blenheim crews were saved by using Whirlwinds as _bait _instead of Blenheims in those "lean forward into France missions."

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## stona (Aug 3, 2017)

Shortround6 said:


> Using enemy aircraft destroyed as a measure of a strike fighters success seems a bit biased.



It served operationally as a fighter for almost two years, from December 1940 until October 1942, and for a bit more than half that time, until December 1943, as a fighter bomber. It is usually most remembered for the latter and shorter period.
263 Squadron diary for 1st December 1943:

_"Our new Typhoons have arrived, with their shiny paint and fittings they rather make the ole faithful Whirlies look a trifle shabby. The latter have given stout service and the squadron have been very proud to fly them."_

Many of the men who flew the obviously liked them, but they were aware that they were coming to the end of their useful service life. After a celebratory dinner given by Westlands for the squadron (described in the diary as a 'piss up', a term familiar to any English english speaker) the next morning

_"Greenish googly faces peering into the CO's office were informed of a Squadron Balbo over Westlands. Three lines of (incredibly crooked) Whirlwinds staggered over Yeovil. If the worthy workers were not impressed, the staff of the Watch Office had their full quota of entertainment by a talk over the R/T by S/L Baker entitled 'Words not in the English Dictionary' or 'Pull your fingers out you bastards.'"_

There were never enough of them to make a significant difference to anything. I think that the most that ever flew together on any one mission was fourteen (when 263 conducted their own anti-flak flying 'Whirlwinds with bomb racks removed'), and generally it was a couple of flights, often escorted by squadrons Spitfires.

Cheers

Steve

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## Shortround6 (Aug 3, 2017)

Their "fighter" missions, from Aug/Sept of 1941 (first raid was to Cherbourg peninsula on June 14th, required staging through Ibsley, but next raid was in Aug. ) sometimes (most often?) included strafing Luftwaffe forward airfields and shooting up what they could find when poor navigation or weather prevented attacking assigned targets. Shot up radio huts or a few planes (in some cases a single plane under repair) don't really make a significant difference but they were attacking ground targets for around a year before the bombs showed up. You are quite right in that often such attacks were conducted by a flight of 4 aircraft. However there were times when 2 or 3 raids were conducted per day. A fair number of Whirlwinds were destroyed or damaged by flak well before the bomb racks showed up. 
No 137 squadrons first operations were ground attack missions and not patrols over the English Channel although that became their mission after being moved to No 12 group.

I will fully grant that with an ammunition load of 240 20mm shells and no bombs these raids were not all that effective compared to what later aircraft could do but the Whirlwinds were flying them and some note should be made of them. The attacks on the distilleries seem to have been a pretty poorly thought out plan. 4 distilleries were the targets (could only be attacked during the harvest season) and only one or two Whirlwinds were assigned to each distillery. Cover for the withdrawal one one occasion, was provided by Spitfires from 3 squadrons. I have no idea if these were full squadrons or part squadrons. This "campaign" required Whirlwinds of 263 squadron to operate from Warmwell. I have no idea if these penny packet (or half penny) raids were a result of low reddiness in the home squadron or the lack of suitable hosting facilities at the temporary base/s. Obviously somebody higher than squadron commanders were planning/coordinating these attacks, which in the end failed to accomplish anything near the goal. Not really a big surprise.

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## stona (Aug 3, 2017)

I would agree with all of that. I think the fact that they were effectively the most heavily armed fighter with really good performance at lower altitudes led inevitably to them being used in the ground attack role, the timing, through 1941/42 is also relevant.

It is also worth remembering that the RAF didn't really 'do' fighter bombers, the first fighter bomber attack in Europe being carried out by Hurricanes of 607 Squadron in October 1941.

Cheers

Steve

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## Shortround6 (Aug 3, 2017)

As to aircraft safety, a good friend of mine's father Flew Corsairs with VMF-214 late in the war, after it had been reformed. He didn't speak much of what he saw in action but did relate several stories from training. He also once said that he was one of two men from his _original _group of pilots to survive the war. 
He did survive a take-off accident that saw both wings ripped of his Corsair, the fuselage flip over with enough force to rip the engine and tail free and him suspended in the harness upside down. He used this story to illustrate the results of though training/indoctrination in an emergency as he reached out, turned off the fuel selector _then _released his harness whereupon he fell on his head.
It was a night take-off and the accident caused by some other personnel who had come back from town drunk and thought it would be funny to turn on a bank of floodlights partway along the runway. He lost his night vision and veried off the runway hitting a telephone pole, a parked bulldozer and finally a stack of cement pipes. 
He also returned from town after a pass to find everyone thought him dead. Another pilot had borrowed his flight jacket with name stenciled across the back and crashed. Tentative identification had been made by the name on the flight jacket. 
Both incidents were stateside before deploying over seas.

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