Westland Whirlwind alternative engines?

Discussion in 'Aviation' started by gjs238, Mar 23, 2012.

  1. gjs238

    gjs238 Well-Known Member

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    In lieu of the Rolls-Royce Peregrine
     
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  2. Shortround6

    Shortround6 Well-Known Member

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    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.
     
  3. yulzari

    yulzari Active Member

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    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.
     
  4. Shortround6

    Shortround6 Well-Known Member

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    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.
     
  5. davebender

    davebender Well-Known Member

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    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?
     
  6. tomo pauk

    tomo pauk Creator of Interesting Threads

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    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.
     
  7. Shortround6

    Shortround6 Well-Known Member

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    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.
     
  8. Edgar Brooks

    Edgar Brooks Active Member

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    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.
    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.
     
  9. Shortround6

    Shortround6 Well-Known Member

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    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.
     
  10. wuzak

    wuzak Well-Known Member

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    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.
     
  11. Edgar Brooks

    Edgar Brooks Active Member

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    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.
     
  12. davebender

    davebender Well-Known Member

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

    Edgar Brooks Active Member

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    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."
    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
     
  14. yulzari

    yulzari Active Member

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    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.
     
  15. wuzak

    wuzak Well-Known Member

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    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.
     
  16. Edgar Brooks

    Edgar Brooks Active Member

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    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.
     
  17. wuzak

    wuzak Well-Known Member

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    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?
     
  18. Shortround6

    Shortround6 Well-Known Member

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    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.
     
  19. yulzari

    yulzari Active Member

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    #19 yulzari, Mar 24, 2012
    Last edited: 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!
     
  20. nuuumannn

    nuuumannn Well-Known Member

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    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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