Witold Kasper

Discussion in 'The light stuff area' started by plncraze, May 1, 2007.

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  1. Oct 20, 2011 #261

    bmcj

    bmcj

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    Though it seems unlikely, I'm willing to admit that there may be nuances to the math and aerodynamics that we are missing that might actually justify his claims. Perhaps the CL numbers are incorrect, and there are other mechanisms at work here, but he does seem to have demonstrated his claims in real life flight demos.
     
  2. Oct 20, 2011 #262

    autoreply

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    I've followed these discussions from the sideline, but I've never seen much of any proof for the claims his supporters make or have made to be honest.

    "Extraordinary claims require extraordinary proof".

    Even the more advanced vortex lift systems don't get an Cl of over 2 and the very best systems still don't go beyond 3.5 or so. A claim of 12, let alone 25 is totally crackpot, or a revolutionary break-through. In the latter case, one would wonder why it didn't reach any major aerodynamics in the last 35 years...
     
  3. Oct 20, 2011 #263

    bmcj

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    I did not mean to suggest that his demos proved his claim of high CL. I meant that he proved the craft is capable of the near vertical "mush mode" descent at a reasonably slow/safe descent rate.
     
  4. Oct 20, 2011 #264

    autoreply

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    Sorry, then I misunderstood your comment :)
     
  5. Oct 20, 2011 #265
  6. Nov 3, 2011 #266

    henryk

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  7. Nov 4, 2011 #267

    henryk

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    BEKAS 079.jpg BEKAS 085.jpg BEKAS 090.jpg BEKAS 138.jpg

    BEKAS 141.jpg 'Drewlot' Wiesław Płonka=fuselage at the end 2011...
     
  8. Nov 5, 2011 #268

    henryk

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    [​IMG][​IMG][​IMG][​IMG] =restoration story BEKAS 083.jpg BEKAS 088.jpg
     

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  9. Nov 8, 2011 #269

    conestogaman

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  10. Nov 8, 2011 #270

    henryk

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  11. Nov 8, 2011 #271

    flinote

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    Sorry--I'm not going to agree with your observations.

    I WOULD agree, if most of the bird landing observations were made on flat land; instead, most of the bird landings are made with management of velocity and the gravity well--that is, the bird finds a level below the landing point and then degrades its airspeed by climbing to the final landing place while the airspeed is deteriorating.

    I know there will be some who argue that the landing performance of waterbirds is a demonstration as required; my answer is, these specialized fliers use the drag of the water which they create with their feet to slow their speed rapidly.

    Also, the issue of flapping to provide additional energy input clouds this issue. In any case, I remain skeptical of extremely high CL quotes, given the Reynolds numbers involved.

    FWIW

    Bill
     
    Last edited: Nov 9, 2011
  12. Nov 9, 2011 #272

    flinote

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    Hi again:

    I didn't see any replies to the posted photos, so I thought I would add my observations.

    First, the famous "tip triangle" which was a distinctive design element of the BKB/Bekas has been modified with a hinge line and a (probably ground-adjustable) trimming device which appears to be a turnbuckle or similar.

    It's interesting to consider the possibilities into researching longitudinal stability and control using different combinations of pitch trim with this device and changes in CG.

    Also noted is a trim-flap, added as a part of the elevon. This one has a linkage and may have been adjustable in flight. The issue of stick forces created by combinations of pitch energy input and airspeeds makes something like this device almost mandatory. There are sufficient examples of excessive aft-stick forces to make it worthwhile to explore a pitch trimmer.

    In all, this would appear to be a later version (or modification) of the original BKB/Bekas concept for more advanced research into tailless/swept wing configurations.

    Bill
     
  13. Nov 9, 2011 #273

    henryk

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    kasperminutes

    =explanation... Obraz=SONY,rysiek,bekas,pobiednik 124.jpg Obraz=SONY,rysiek,bekas,pobiednik 125.jpg
     
  14. Nov 9, 2011 #274

    henryk

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    Last edited: Nov 10, 2011
  15. Nov 10, 2011 #275

    henryk

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    ARKive - Skylark video - Alauda arvensis - 13

    A male singing from the sky, then descending to the ground and finally flying away | the Internet Bird Collection

    Hovering of the skylark - YouTube
    =hovering

    -in my observations from short distance of the last phase of fly=vertical mush with stopped wings
    =Vvert =circa 1m/sec!

    Cl=Cd=G/S*Vvert*Vvert =extremally high...
     
  16. Nov 12, 2011 #276

    danmoser

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    Henryk,
    I notice that the BEKAS has vertical tip rudder hinge (no sweep).
    It looks like your new composite wing has the hinge line swept ~45 degrees.
    Please describe the benefits of the hinge line sweep, and testing done on it.
    Thanks!
     
  17. Nov 12, 2011 #277

    henryk

    henryk

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    =BKB-1,
    =BKB1-A,
    =BEKAS-N:
    =hinge line vertical+ elevons

    =KASPERWING,
    =hinge line=45 degreas,no elevons!
    =V=circa 60 degras

    =composite K-wing =h.l=45 deg.
    =V=90 deg.,no elevons,

    its a pity=not yet examinated!\my be=winter\.

    http://www.twitt.org/Webb-a.jpg

    wkasper PICT4978.jpg ,bogdan.laminat 006.jpg
     
    Last edited: Nov 12, 2011
  18. Nov 12, 2011 #278

    henryk

    henryk

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    As a former & hopefully future Kasperwing pilot (I'm hoping to buy another soon)

    Hallo,Dan!

    do Yoy know water-start distance \at high AoA,beyond 30 deg.\?

    Kasperwing on Veengle
    =on the old video=under 10meters\30foot\?
     
  19. Nov 15, 2011 #279

    danmoser

    danmoser

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    I've never flown on floats, but that's an interesting takeoff technique in the video... shift weight way back to get the bow out of the water.
     
  20. Nov 15, 2011 #280

    danmoser

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    The rudder hinge line for the Kasperwing ultralight is hardly swept back at all.. certainly not close to 45 degrees.
    But yes, the endplates & rudders are inclined outward, forming a V with angle between them of 60-70 degrees.

    the later Fledgling hang gliders had about 20 deg. hingeline sweep, but not inclined.
    Opening a rudder creates a yaw moment from the inward lift and tip drag.. .and the swept hinge line also forces the tip downward somewhat, especially when opened all the way.

    Because of the inclined rudders on the Kasperwing, it LIFTS the tip somewhat when the rudder is opened.. the opposite of the Fledge... both seem to work.
     
    Last edited: Nov 15, 2011

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