Would a thin/redesigned wing brought the Hurricane up to Spitfire/109 performance?

Discussion in 'Aviation' started by pinsog, Aug 17, 2013.

  1. pinsog

    pinsog Member

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    Would a thin/redesigned wing brought the Hurricane up to Spitfire/109 performance levels during the BoB timeframe?
     
  2. swampyankee

    swampyankee Active Member

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    No.

    Take a look at the remainder of the aircraft.
     
  3. pinsog

    pinsog Member

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    Can you expand on that opinion please? Is the rest of the aircraft that unaerodynamic?
     
  4. nuuumannn

    nuuumannn Well-Known Member

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    No because that would have constitute redesigning the entire centre section of the aeroplane from the firewall to aft of the cockpit to take the redesigned wing thickness. The Hurricane was built around a welded steel tube framework that the wing carry through structure was fixed to and the wings bolted onto. Its a major rework and it depends on when the work was begun as to whether it was ready in time for the Battle of Britain. Hawker would have been better off designing a new airframe, which they had underway by that time - the Tornado and Typhoon, which also had thick wings.
     
  5. pinsog

    pinsog Member

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    #5 pinsog, Aug 17, 2013
    Last edited: Aug 17, 2013
    Could the wings have simply tapered down within a foot or so of where they bolted to the fuselage? Not trying to argue, I simply don't know so I am asking. Seems like a relatively simple fix for someone who doesn't work on airplanes.

    I'm thinking the center section where it bolts to the fuselage stays the same, but out side of that it immediately tapers down to a wing of proper thickness. Again, seems to me like that could be done rather easily and not disrupted production. BUT, I may be completely wrong also.
     
  6. nuuumannn

    nuuumannn Well-Known Member

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    You've still got that thickness at the wing root. You can't alter that without redesigning the centre section, also because if it was thinner, there wouldn't be enough room to put the undercarriage. If you were to make the wing thinner in the fashion you suggest, again, you are looking at major redesign, since you have to consider the armament layout. The Hurricane had all its guns in each wing concentrated in a single box, apart from later marks with guns out board of that, but that would not necessarily be possible with a thinner wing, the guns would be spaced out along the wing like the Spitfire, which wasn't necessarily a hindrance, but it requires redesign nevertheless. Take a look at the picture for reference.

    [​IMG]

    You also have to look at the trade off between amount of effort required to carry out such work and the performance gain earned from doing it. The end result might not be any greater increase in performance than what the Hurricane originally offered. Besides, what Swampyankee was alluding to was that the Hurricane was significantly bigger than both the Bf 109 and Spitfire, therefore it was a more draggy airframe.
     
  7. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Of course.
    Hurricane's wing was not just thick, it was of great area - some 50% more than Bf-109, Yak fighters or MC.202. So it's not hard to envisionage a better performing Hurri with smaller thinner wing. Quirk might be having fuel, U/C and armament it the new wing in the same time, though.
     
  8. OldSkeptic

    OldSkeptic Active Member

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    There are (as mentioned above) major technical issues in doing it, but in theory yes.

    We can see this in the Typhoon to Tempest conversion. On the same engine power the Tempest was about 25-30 mph faster. Given that the radiator stayed the same and the fuselage was similar, only longer, then it was just the wings that made the difference.

    Pre WW2 the British (and other) aerodynamic scientists of the time believed that the thickness of the wing was irrelevant to wing drag, Camm believed them, Mitchell didn't (he thought it was nonsense).
    Note that Camm still stuck with a thick wing for the Typhoon, despite it being a much later design and the experience of the Spitfire was rather evident to all (also being 25-35mph faster on the same engine power).
    But to his credit, when the penny finally dropped he got the Tempest out pretty fast producing an excellent plane (which later became the basis for the even more superb Fury and Sea Fury). It was also semi-elliptical too (as was the earlier P-47s).

    The thinner the wing the better it got as the speeds went up with more engine power as the war went on. Drag increases with the square of the speed ... until you get into the transonic region, where is goes up exponentially. A big thick wing means part of it will have a lower critical mach speed, the point where it become turbulent and the drag goes up, it also moves you into the region where you start to lose control because the pressure distribution moves and/or shockwaves start hitting the elevator.

    So not only was the Spit less draggy than the Hurri in the lower speed range, it also had a much higher mach limit which meant (a) that big increase in drag was at a much higher speed and (b) you maintained control to a higher limit.

    Hawker, at one point proposed (I think from memory) putting a Griffon into the Hurricane and "it would do 400mph", the Air Ministry laughed at them and told them not to be so silly basically. You would have had to put a rocket into a Hurri to get it to 400mph.
     
  9. wuzak

    wuzak Well-Known Member

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    Was the Tempest's wing really that thin? Certainly thinner than the Typhoon's, but not as thin as the Spitfire's.

    The big development with the Tempest was the laminar flow wing.
     
  10. OldSkeptic

    OldSkeptic Active Member

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    Repeat after me "there is no thing such as a laminar flow wing, there never has been and, probably never will be". It is one of those laboratory things that is impossible in the real world.
    When even a bug splat (or a single speck of dust) will destroy the 'laminar flow' this is not something that can be achieved in real life.

    No commercial airliner (or military aircraft) even attempts to have a 'laminar flow' wing. Though there are continual attempts in the lab. Some gliders have wings like that .. sort of ... and if they hit some bugs ... their performance goes down ... a lot.

    The Mustang did not have a laminar flow wing (nothing really ever has), but, by accident it was thicker than a Spit's (making room for fuel tanks) and had a good mach limit (where drag goes exponential and control is lost).
    It had the best mach limit of any US fighter (by a long margin), though none (until much later with swept wings) was as good as the Spit's.

    Interestingly the Mustang's wing could, under certain flight regimes it, near its mach limit, would pitch up, rather than the usual (and often fatal) pitch down. Plus it sent good signals to the pilot that 'it was not happy' before the fatal limit was hit (typically it would porpoise). A great piece of aerodynamics, albeit mostly (as was the Spit) accidently at those high mach levels.

    Contrast to the P-38. Later models were limited to very shallow dives (even with the dive recovery flaps), after so many pilots dived after a German fighter .. and were never seen again. The very late models maximum level speeds were very close to the mach limits. Hence its failure in the ET, since both the 109 and 190 had good mach limits (again by accident).

    The Tempest's better performance (over the Typhoon) was purely caused by its thinner wing.
     
  11. tomo pauk

    tomo pauk Creator of Interesting Threads

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    #11 tomo pauk, Aug 18, 2013
    Last edited: Aug 18, 2013
    It was, in percentage terms, a thin wing - 14.5% thickness to chord ratio. Spitfire went for thinner wing, 13% and something. The laminar flow wing* ofered further reduction in drag, Tempest vs. Typhoon, despite greater wing area of the Tempest.


    *okay, as laminar as it was feasible
     
  12. fastmongrel

    fastmongrel Well-Known Member

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    If a thinner wing isnt possible would there have been any advantage to a cropped wingtip. I believe Spits with cropped wings were faster at low level and rolled better.
     
  13. Shortround6

    Shortround6 Well-Known Member

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    As achievable in the real world a laminar flow wing maintained the "flow" to somewhere between 30-40% of cord. Normal wings of the time maintained the flow to 20-25% of the cord. On the Mustang the airfoil used had the max wing thickness further back along the cord than a 'normal' airfoil and had more internal volume than a 'normal' wing/airfoil of the same thickness and cord.

    And it is not only the leading edge that can screw things up. The thickness of paint for the national insignia screwed up the airflow on a mustang wing.
     
  14. Shortround6

    Shortround6 Well-Known Member

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    Not much. And as you noted the advantage is only at certain altitudes. At others the "advantage" disappears or reverses. A Hurricane may have picked up 3-5mph with a modest crop like the Spitfire, a radical crop (25% of the wing area) might have picked up 9-10mph. Cutting the tips off not only reduces the wing area but changes the aspect ratio and the aspect ratio has a little bit to do with the overall lift coefficient of the wing. The winglets used on many modern aircraft do several things but one of them is fooling the airflow so that acts like a higher aspect ratio wing.

    An old text book (WW II era or before) figured that cutting the wing area by 25% would improve top speed by 3%. However that size cut increased stalling speed by 15%. since stalling speed is not only landing and taking off but turning you have to be carful of trade-offs. GO back to the Spitfire and look at the ceilings of the clipped wing and extended wing aircraft. The Spitfire had very minor changes in wing area but the changes affect the ceiling much more (change in aspect ratio).
     
  15. Timppa

    Timppa Active Member

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    #15 Timppa, Aug 18, 2013
    Last edited: Aug 18, 2013
    You don't seem to be aware that the change of fabric covered wing to all metal wing of the Hurricane Mk I was a major rework.
     
  16. nuuumannn

    nuuumannn Well-Known Member

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    I'm well aware of it, but firstly, the wing thickness was not changed and secondly the work was begun prior to the outbreak of war - in time for the Battle of Britain. Re-read my first post; it states that any work would have to be done within a suitable time frame.
     
  17. drgondog

    drgondog Well-Known Member

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    Swampyankee is correct with fewer words expended.

    The Hurricane had a lot of Parasite drag due to the fuselage, radiator, canopy, etc design in contrast to say a 109F or Spit (or Mustang). The wing could have been redesigned to reduce the largest drag factor - but not likely to a level below the 109 or Spit.
     
  18. OldSkeptic

    OldSkeptic Active Member

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    The thing to remember is that the Hurricane was no 109 or Spit, both of which were radical and the most advanced designs for the time. It was an evolution (re-engineering) of an earlier bi-plane.

    It was originally marketed by Hawker as the 'monoplane Fury', that is the prior Hawker bi-plane Fury with a single wing.
    If you look at photos of the two you can see the resemblance.

    As a result it was late 1920's/early 1930's aerodynamics and construction. Tubes and fabric and so on.
    Hence the original fabric wing, which had to be changed.

    Technically obsolete even in the BoB as it was giving away 25-30mph to both the, similarly powered, Spit and 109.
     
  19. nuuumannn

    nuuumannn Well-Known Member

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    I agree Old Skeptic, but it wasn't technically obsolete by the BoB; its design and method of construction was very much current technology and in use in many different aircraft designs around the world in 1940 - the most advanced technology was that displayed by aircraft such as the Spit, Bf 109, Hawk 75, DC-3 etc and all metal construction was most certainly prevalent and the way forward, but welded steel tube and covered in ali panels and fabric was very much de rigeur of many in-service designs still under production; Fiat BR.20, Fokker D.XXI, Morane Saulnier MS.406, Vickers Wellington, Avro Anson, SM-79 etc.

    You also have to remember that the Spit's and Bf 109's in service performance was extraordinary at that time; the majority of fighters in air forces around the world were closer to the Hurricane than they were the Spit and Bf 109.
     
  20. razor1uk

    razor1uk Well-Known Member

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    #20 razor1uk, Aug 19, 2013
    Last edited: Aug 19, 2013
    Some good points and discussions :D
    Love the one about laminar flow is a laboratory term; yep that is a true fact, in everyday life, laminar flow is just a term to describe a more efficient ratio of ratios used in wing design, where the longer gentle smoother the curve without the older style with more of teardrop like leading edge is more efficient. Laminar flow means that the layers of airflow around an object are morelikely to follow its shape smoothly with less percentage of those layers generating unwanted currents, eddies along the profiles shape.

    In real aerial life, air isn't channelled and directed from shaped vents or venture/venturii (..plural of venturi?) onto a test subject (wing section and or scaled model etc) all the time; that natural air particles/fluid movement do also rise, sink and pin ball off each other in relation to their own and surround temperatures, their vectors, forces and unknown quantum interactions with other particles in such a linear manner as modelled in the laminar flow experiments. Of course an aircraft moving at speed in 3 Dimensions of axis is going to create its own combinations of interactions and distortions in and with the air - hence why laminar only exist in the lab. I apologise for being a pedant who is currently pedantic.

    Although boundary layer blowing from some form of compressor bleeding of upto less than 30% engine through flow, does achieve similar effects when it is used as needed - generally only ever used during take off, landings or for slow speed flight - and nearly only on some military jets, but I digress, as that mostly doesn't apply for early WW2 or for most nations until the mid to late 21st C...
     
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