Shoulder wing unpopularity

Discussion in 'Hangar Flying' started by stanislavz, Nov 9, 2019.

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  1. Nov 9, 2019 #21

    TFF

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    I have seen a couple of Durands at Oshkosh. I think one may have been the prototype. The grandson of the designer posted a little on HBA when he inherited the plane.
     
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  2. Nov 9, 2019 #22

    stanislavz

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  3. Nov 9, 2019 #23

    stanislavz

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  4. Nov 9, 2019 #24

    crusty old aviator

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    Oh, there’s supposed to be a step there above the front gear attach! The guy who built my friend’s Cygnet must have whacked his knee on it one too many times and cut it off...what a dope.
     
  5. Nov 9, 2019 #25

    cheapracer

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    Yes, I am very keen on staggerwings, and I spoke to him last year I wanted to build them. Sadly the design is a dog's breakfast, that's Australian for bits everywhere, far too complicated a build, and I just didn't have the energy at the time to sort it out. Still love it though!


    Love that even more without the struts of the Durand! ... off to investigate that one now.

    ... but they ain't 'Mid Wings' are they.
     
  6. Nov 9, 2019 #26

    stanislavz

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    Nope - but solving same problems - view and getting in into cockpit. And going into composite way - hey, 4 wings is easier to make, than 2, but bigger. I am getting into this back and forward N times already.. Always trying to find an not very weird "duck"
     
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  7. Nov 9, 2019 #27

    Riggerrob

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    Frenchman Pottier also designed his all wood, P-130 Coccinelle, Bleu Citron which is in the same class as Cygnet. At least 20 P-130s have been built by amateurs.
     
  8. Nov 9, 2019 #28

    cheapracer

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    Yes.

    ... and no, doesn't have to be composite.
     
  9. Nov 9, 2019 #29

    stanislavz

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    But would win a lot..
     
  10. Nov 9, 2019 #30

    Riggerrob

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    Also consider the Australian Hornet, Barber Snark (NZ) and ARV Super 2 (UK). Nord built a hundred or so NC.850 airplanes - with side doors - circa 1950 and an up-engined version spotted artillery fires for the French Army.
    As for aero-elasticity .... as long as you keep forward-sweep to less than 10 degrees, it isn’t a problem. Swallow sweep also allows you to install wing ribs at 90 degrees to spars, simplifying construction.
    Aerodynamic stalls are much the same as rectangular wings, which naturally stall first at roots, then gradually spread outboard with tips to all it last. Shallow sweep angles (less than 10 degrees) limit centre of lift shift relative to the centre of gravity.
    The thin wing root and swept-back leading edge create enough turbulence to guarantee that swept-forward wings stall root first. Wittman Tailwinds have similar wings and moderate stall characteristics.

    Cygnet solves aero-elasticity problems with geodesic construction: lots of slender wooden stringers laid on the diagonal. Geodesic construction can be thought of as stressed-skin with lots of lightening holes.
    Modern homebuilders would rather install one piece plywood, aluminum,etc. wing skins.

    Weight and balance is similar to the popular RV-12 kitplane where the pilots’ buttocks rest against the main solar. Then clever designers limited nose-heavy tendencies by installing the firewall as far aft as possible while still allowing sufficient leg room. Van even cheated by stepping the lower firewall forward to allow rudder pedals to almost nestle under the rear cylinders. The upper part of the firewall is stepped backwards to allow room for engine accessories like magnetos, pumps, etc. at crankshaft level. They installed a light-weight Rotax engine the minimum distance forward of the firewall. As many engine accessories as possible (battery, fuel tank, etc.) are aft of the wing soar to help balance.
     
    Last edited: Nov 9, 2019
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  11. Nov 9, 2019 #31

    BBerson

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  12. Nov 9, 2019 #32

    Vigilant1

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  13. Nov 9, 2019 #33

    BBerson

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    Fred said he was surprised to find how light a Cessna 172 wing was, after building his foam wing airplane.
     
  14. Nov 9, 2019 #34

    Dan Thomas

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    Yup. The original composite concept promised lighter construction, but in my maintenance experience I have found composite airplanes like the Cessna 350/400/Corvalis/ttX (they kept changing it) and the Cirrus to be dismayingly heavy, much heavier than their aluminum competitors of the same class. And I've moved a lot of 172/182/180/185 wings, too. Light. An empty fuselage doesn't weigh much, either.
     
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  15. Nov 10, 2019 #35

    Dan Thomas

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    Cessna did that to the 172 more than 50 years ago. It carried through to the 177.

    [​IMG]

    Some other airplanes have sloped firewalls to achieve the same thing. The PA-28:
    [​IMG]
     
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  16. Nov 10, 2019 #36

    Dan Thomas

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    To me, the shoulder-wing is nice for visibility, but one also has to weigh safety, specifically egress when inverted. The typical low-wing airplane has a real problem there, and an airplane like the Cygnet doesn't improve on it at all. A high-wing airplane is much more likely to let its victims out quickly.

    The Lake amphibs are shoulder-wing affairs, but CG movement is large because everybody in it is ahead of the CL. When everone is out you can lift the nosewheel off the ground with no effort at all. The tail of an LA-4 will almost stay on the ground if you put it there. That presents a problem when tied down in the wind, so the control lock holds the elevator down. With the wind on the tail, though...
     
  17. Nov 10, 2019 #37

    Pops

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    Firewall on the SSSC #2. Built for the longer flywheel drive VW engine. No shorter leg room to the rudder pedals.
     

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  18. Nov 10, 2019 #38

    cheapracer

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    Of course, but it limits, not eliminates.

    I have read too many stories/incident reports of stupid people who fly CoG too far aft, to give them a helping hand in crashing.

    .. and they are still ugly, lol.

    Another perspective is I am Australian. There's a clear choice, low wing without struts, or high wing to keep you out of the baking sun. I don't like struts, if I do a high wing it will be cantilever, then you can have normal doors/ingress/egress.

    Mid wings usually require struts due to the general lack of structure to attach to, so the aero advantage is nullified, so may as well have a low wing.
     
  19. Nov 10, 2019 #39

    jedi

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    Mid wing has interference drag on both the upper and lower wing fuselage junction.
     
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  20. Nov 10, 2019 #40

    mullacharjak

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    Believe me there are Tons of mushaks flying where I am.I see scores of them buzzing around daily.Its been flying since 1975.There are no bad reports about it.I think shoulder wing aircraft are best for sport/recreational flying and if the
    mushak is any yardstick i would say they are all great.
    The cygnet geodetic is not a problem.I have the drawings in front and you just install the 5/32x 3/4 inch pine strips in criss cross manner over the inverted wing FIRST and then the top.Labour intensive but not difficult.I also have the P130 drawings(no geodetics there)
    Here its hotter than australia so dont know how the mushak pilots cope with the hot sun but they do.
    If someone can get a plan/pack as aeromodellers call it from AMF you can build your own mushak.Its such a simple boxy aircraft.A plan/pack is supposed to have a plan/ cowl/canopy and in this case pre formed glass fibre landing gear strut.
    You can use a ford/toyota/suzuki/mitsubishi/bmw v6 engine and get a very rugged sport aircraft.
     
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