Redesigning the Defiant.

Discussion in 'Aviation' started by Njaco, Jan 4, 2013.

  1. Njaco

    Njaco The Pop-Tart Whisperer
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    One of our new members onetenor (John) had a great comment in another thread:

    Hmmmm, what do you think?
     
  2. Aozora

    Aozora Well-Known Member

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    In fact B-P did test the prototype Defiant K8310 in August 1940 without the turret, and with a projected armament of 12 .303s or 4 20mm Hispanos. Top speed with Merlin XX was 360 mph @ 21,700' with a climb rate of 3,235 ft/min at sea level. I'll dig out Buttler's book and post the details.
     
  3. tyrodtom

    tyrodtom Well-Known Member

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    The empty weihjy of the Defiant was over a 1000 lbs more than the Hurricane Mk I, Just removing the turret wouldn't remove all that extra weight, the fuselage was 4 ft. longer, plus all the extra structure for the turret. It'd take a lot of redesigning to eleminate all un needed structure, and adding 4 guns to each wing, like the Spit and Hurricane had at the time.

    A lot of time and trouble to just come out with something equal to a Hurricane, maybe. No way that it would be up to Spitfire standards.

    You'll notice those figures are with a "projected " armament.
     
  4. CobberKane

    CobberKane Banned

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    What was the construction of the Defiant? Closer to the 'foot in both eras' build of the Hurricane than the monocoque Spitfire, I suspect. Hard to imagine a bastardised Defiant could match the purpose built single seat Hurricane, let alone the thoroughly modern Spit. The postulated performance figures cited earlier sound a bit fanciful, surely.
     
  5. fastmongrel

    fastmongrel Well-Known Member

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    The Defiant was a monocoque design and actually just about the most advanced construction plane flying as it was designed for prefabricating in sections which were bolted together. It was a generation ahead of the Spit, which still doesnt mean it would make a fighter.
     
  6. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Maybe turning it into a long range fighter? Ditch the turret, relocate the pilot's compartment further aft, use the space between pilot and engine to house the fuel tank, so the space previously used by wing fuel tanks now can house the forward-firing armament. Later add the bubble top, maybe clean a little bit of antennae.
    def.jpg
     
  7. Aozora

    Aozora Well-Known Member

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    Reading Tony Buttler's description, B-P proposed a P-94 single seat fighter, using components of the Defiant, and tested K8310 without the turret in order to try and work out how the new design might perform. As tyrodtom has noted the Defiant would have to be completely redesigned to be anywhere near the Spitfire in performance, and the Air Ministry obviously thought that with the Typhoon/Tornado, Whirlwind and Beaufighter already flying a new design would be a waste of time.
     
  8. fastmongrel

    fastmongrel Well-Known Member

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    #8 fastmongrel, Jan 5, 2013
    Last edited: Jan 5, 2013
    Nice images Tomo the bubble canopy one looks brilliant. Put a different radiator housing on maybe a P 51 one, a retractable tailwheel, remove the radio masts and you have a super sleek looker.
     
  9. yulzari

    yulzari Active Member

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    With it's wider undercarriage track, space for large extra tank near the centre of gravity, a cockpit slightly further forward than the Spitfire/Hurricane and a substantial centre section to mount wing fold joints the Defiant has been a perennial favourite in forums to be the FAA fighter it needed.

    Not only did Boulton Paul install 8 x .303 in K8310 but did the design work for 4 x 20mm.

    The production of the Defiant was far easier than a Spitfire and would have made shadow factories quicker to set up and disperse production and you would not have to build Fulmars or Sea Gladiators nor use shipping for Martlets.

    However, remember that in OTL the Defiant was only coming fully on stream in mid 1940 and making them construct Blackburn's Roc's was no help.
     
  10. nuuumannn

    nuuumannn Well-Known Member

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    #10 nuuumannn, Jan 5, 2013
    Last edited: Jan 5, 2013
    K8310 photographed on 13 August 1940.

    [​IMG]

    The P.94 was intended as a stop-gap in case of losses of Spitfire and Hurricane exceeding production. Like the Miles M.20, the idea was dropped once it was proven unnecessary.
     
  11. fastmongrel

    fastmongrel Well-Known Member

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    Nice pic Nuuuman. Dont know if its just an optical illusion but that wing looks very thick for a fighter. Possibly built like that to get the turret fighter off the ground as quickly as a lighter single seat job off a grass field.
     
  12. Shortround6

    Shortround6 Well-Known Member

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    As part of the redesign you have to move the fuel tanks. On the Defiant they are in each wing just outboard of the landing gear or just about where the prop disk ends. Right where you want to put the wing guns.

    Yes it can be changed and perhaps it was on the prototype but it is just one more thing to move and jigs to be changed.

    Moving the tanks to fuselage can be done but pretty much just replaces teh wing tanks and so does not turn the "new" plane into a long range fighter.

    I don't know it was lack of wind tunnels or what was going on but a number of British planes in the late 30s and 1940-42 had an awful lot of trouble coming close to "projected" performance figures. The Defiant only gained about 10-12mph when fitted with a Merlin XX engine instead of the Merlin III. A gain of around 20% in power. In part because of a less than ideal radiator and oil cooler set up. Getting rid of the turret was unlikely to increase the speed by 40-50mph.

    A single seat Avenger certainly showed little improvement (5-10mph?) by getting of the turret AND fairing in the lower gun position. Granted a much larger airplane.
     
  13. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Done this sqetches a long time ago. The Defiant's fuselage was 'fatter' than Spitfire's, the engine was far more forward than Spitfire's. Should give a far more fuel than standard Spit, twice as much?
    The thick wings would be the major obstacle to get above 350 mph, let alone a higher mark. A plane good for CBI, maybe for MTO?

    tops.JPG

    sides.JPG

    front.JPG
     
  14. Shortround6

    Shortround6 Well-Known Member

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    Again, why bother. Cancel later Defiant production, Give Boulton Paul a contract for Spitfires, fit 30-45 gallon tank under fuselage.
     
  15. tomo pauk

    tomo pauk Creator of Interesting Threads

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    You mean the rear fuselage tank?
     
  16. Shortround6

    Shortround6 Well-Known Member

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    No, just a simple drop tank.

    By the time the MK II Defiant shows up in production it is the Winter/Spring of 1941 (Feb ?). Prototype did fly in July or August of 1940. A redesigned single seat Defiant is going to be competing with MK II and MK V Spitfires and MK II Hurricanes.
     
  17. stona

    stona Well-Known Member

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    I agree,though more accurately failing to compete :)

    Cheers

    Steve
     
  18. tomo pauk

    tomo pauk Creator of Interesting Threads

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    You know better than me that even a 170 gal drop tank is not going to turn a Spitfire into a long range fighter, unless the internal fuel is also increased. Defiant have had a longer fatter fuselage, hence a better prospect for a greater fuel tankage. Adding the wing attachment points for drop tanks should not be a long stretch.
     
  19. Shortround6

    Shortround6 Well-Known Member

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    Doesn't really matter what the range is if the thing is a dog in combat.

    The only chance it had at being a single seat fighter was in 1939, before the first ones were issued. By the summer of 1940 when the Prototype single seater flew it was a dated design.

    Much is made of the "projected" 360mph top speed. This was "projected" using a Merlin XX engine at 21,700ft. Also projected was the ability to out climb a Hurricane IIc at sea level by about 500ft/min and be able to climb to 25,000ft in little more time than the Hurricane IIc took to get to 20,000ft.
    All this while carrying 4 20mm cannon AND four .303s AND the 20mm guns could pivot downwards by 17 degrees for ground strafing.

    As noted already, Production MK II Defiant's using the same MK XX engine gained a whopping 10-12mph over the MK Is.

    The Spitfire with drop tanks wasn't going to be a long range fighter but at least it COULD fight in the areas it could reach.

    This single seat Defiant wouldn't reach service use (with the MK XX engine) until the spring/summer of 1941.

    While a bit later in timing the P-40F makes a good reality check, A bit smaller wing, a smaller fuselage, lighter weight armament, Fuel load??? and goes 360mph at 20,000ft with the same engine.
     
  20. Njaco

    Njaco The Pop-Tart Whisperer
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    Wow, this has turned into a cool thread! Thanks for the great opinions, everyone!
     
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