Wing of the "Kasperwing" in sailing?

Discussion in 'Hydrodynamics and Aerodynamics' started by Konstanty, May 2, 2016.

  1. Konstanty
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    Konstanty Junior Member

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  2. upchurchmr
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    upchurchmr Senior Member

    First you have to get someone to believe the fact that it works.
    I had a friend who had one and even after watching him perform the manuvers claimed, no one was interested.

    The explanation in the first link, does NOT match how Kasper said it worked.
     
  3. Doug Lord
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    Doug Lord Flight Ready

  4. Skyak
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    Skyak Senior Member

    It is not apparent to me that anything good has been accomplished by this design. It is just a crude end plate that can be depowered. I think you would have less drag from variable camber or twist. It does look like it could wipe out lift on the tip fast.
     
  5. upchurchmr
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    upchurchmr Senior Member

    You would really need to look up what Kasper says.

    This is not just a crude end plate, but the application is an ultralite aircraft not a boat.
    one of his desires is to be able to pitch up the aircraft until you are coming straight down with zero fwd windspeed. At that stable position, he says the endplate (vortex control) will allow you to gain fwd speed, go backward, or rotate the aircraft on command. His design is such that you can land it with zero fwd speed without damage to aircraft or pilot.

    Additionally he says that compared to other ultralites, you can have a equal top speed with a smaller motor. Or if it was legal, higher top speed with equivilent motor. As I remember, the legal top speed is ~60mph.

    The primary claim for this wing system is the control and efficiency it offers.

    Its not obvious to me how you translate this into a sailboat wing.

    But you really need to investigate farther before making an uninformed judgement.:p

    OBTW, I witnessed the vertical decent with control, personally.
     
  6. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The Kasperwing is more than a wing and though has some interesting attributes, much of it isn't applicable to a boat. The arrangement on this wing trades off lateral control for some slow speed characteristics. The kasper interpretation of these wingtip rudders are based on a few previous approaches. He took the advice of previous reports, shortened the elevons, enlarged the rudders and added stabilizers. I can't see how any of these features of the evolution of this wing style would be beneficial to a sailboat. We have quite effective semi rigid sail plans available. We also have single and multi element rigid wings on sailboats as well. What would be the advantage of the Kasperwing approuch?
     
  7. Skyak
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    Skyak Senior Member


    I saw the claim about 0 velocity landing and I also saw the drawing of the stabilizer operating - showing the vortext spinning off the rear INDICATING FORWARD AIR VELOCITY.

    I do NOT have to to chase this guy all over the internet to offer an educated opinion ON THE DATA GIVEN. And that opinion is still the same -camber and twist are more effective and lower drag. All your additional explanation amounts to is 'oh, he meant to add drag. Now it's a parachute!' To which I add that in drag power a spinnaker is twice as powerful and less than a tenth the weight. The wing shape has the big camber forward you expect for high lift -then it has a huge decambering in the tail destroying that lift and adding drag. There may be some positive interaction with the prop, but we are only considering application to sailing.

    What is so impressive about vertical landing if there is no vertical takeoff?

    I can't say how his compares to other ultralights but fundamentally it seems it could be improved.
     
  8. upchurchmr
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    upchurchmr Senior Member

    Funny comment that we get here a lot.

    "I can't say...." but "it could be improved".

    What you said is you don't know anything about the subject, but you are willing to criticize.

    I don't know why that is worth something, IMO.
    Don't take offense, just my un-educated opinion - same as yours.

    You will never know what the real intention or design goals are if you "don't chase this guy all over the internet". That's why I pointed out that the links provided have little or nothing to do with the designers intent.

    You of course can comment on useless information all you want.

    I certainly agree that twist and camber will be more appropriate to a sailboat.
     
  9. Skyak
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    Skyak Senior Member


    What I said is I have no idea what other ultralights he claims to be better than or why but I can rule out efficient lift that would be useful to a sailboat. I have no judgement on what he achieves in an ultralight. I am answering the question posed by the OP based on the info he provides. An endplate is less efficient than a wingtip which is less efficient than a wing with the span added horizontal rather than vertical. I'm educated enough to know that is the answer, but I leave the tread to find value if they can.

    You are the one quoting out me of context, calling me names, trying to redirect the tread away from the question and yet you have no other answer but to agree???!!! So all your words have no other purpose than to piss me off?

    If there is something more to it that we should consider then post the link! We have no explanation for the unique "S" cross-section. I presume it is for controlled stall but I was taught it destroys lift and adds drag.
     
  10. upchurchmr
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    upchurchmr Senior Member

    The S section causes the center of lift to remain in the same position with different angle of attack. If you chased the internet you would have seen that as a fundamental starting concept for the Wing.

    If your comments were all about usefulness of the Kasper Wing to sailboats, then I apologize.
    Didn't look like it to me.

    And my point was that not understanding the intent of the design as an ultralite will not allow you to rationally convert it to sailing.

    Calling you names? I just looked back and don't see that. Are you feeling touchy today?
     
  11. Skyak
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    Skyak Senior Member

    " "I can't say...." but "it could be improved".

    What you said is you don't know anything about the subject, but you are willing to criticize."

    THIS IS THE DEFINITION OF QUOTING OUT OF CONTEXT

    "Don't take offense, just my un-educated opinion - same as yours."

    DON'T DEMEAN MY EDUCATION.

    You spend several posts implying I can not figure out the performance of a foil from a drawing but you are so smart you know that I don't understand? And I am missing points but you never post the ANY evidence you claim exist. WHAT ARE YOU SAYING I MISSED??? If you have evidence, post it.

    FYI I follow up and investigate promising designs and technology -why would I chase things that have yet to show value?

    Feel free to disregard anything I say (or adopt it as your own answer) but don't tell me what know or make me the issue.
     
  12. upchurchmr
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    upchurchmr Senior Member

    I have Kaspers monograph on his aircraft design.
    I'm not going to scan 50 pages if you aren't willing to look a little farther.

    I'm not criticising your "formal" education - I have no idea what it is.

    Education in this case means your education about Witold Kaspers design.
    Obviously you know nothing about Kaspers designs since you say it shows no value - and I am talking about aircraft.

    I am talking to you so I am not disregarding what you say. It just that you say you don't know about the subject then clearly judge out of context/ knowledge.

    I'm done, mistate all you want.
     
  13. Easy Rider
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    Easy Rider Senior Member

    I have owned, built and flown a Kasperwing UL.

    I have done the "vertical mush" many times.
    The wingtips are very effective as are the rudders. The response of this wing in all ways is slow and predictable. Not what you'd expect from a tailess aircraft. It can be flown at 18mph in full control w/o tip stalling and as I recall there is no washout. Most vertical mushing is done w some fwd speed probably 7 or so mph. Vertical sink rate I think was about 500fpm while flying normally at 18mph was about 200fpm.

    Personally I think the airfoil and extended airfoil at the wingtip holds the best posibility for sailboat design. The airfoil is very stable and would be easy to control as a wing for the boat. But it's a single surface wing and would only function with the wind coming from one side of the boat. The airfoil does not work with a negative angle of attack. So I don't see any way to use Kaspers UL aircraft wing for a sail on a boat.
     
  14. Skyak
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    Skyak Senior Member

    I can handle tacking the asymmetry, but all indications are that lift/drag is low. The ability to go from low lift/drag to no lift/drag is of no value to a sailboat.

    Out of curiosity, what is the takeoff distance like and power for cruising speed compared to classic profile ULs?
     

  15. Easy Rider
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    Easy Rider Senior Member

    Skyak,
    Take of roll was about 75'.
    Had a 22hp Zenoah 250cc single cyl two stroke w free air cooling w/o fan. Climb about 800fpm and cruise was 6-8hp. The early K wing had a 100cc 15hp cart engine. Lift to drag ratio was just shy of 10-1 at a very slow speed ... about 30mph. Stall speed about 20 and cruise was best about 30. Would cruise at 40 with increased fuel consumption and less comfort. Flat out at 50mph.

    Performance was far above typical UL's especially the ability to climb, cruise and fly on very little power. Fuel consumption was about 1.25 gph whereas most UL's burned 2.5 to 3gph.

    Essentially it was a powered hang glider w wheels.
     
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