Roadable Aircraft DESIGN

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by WonderousMountain, Jan 23, 2012.

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  1. Sep 18, 2013 #1601

    Aircar

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    Re the 'limit' on speed of a Kasperwing --is this due to the limitation of weight shift in the high wing wire braced one or even the drag moment of the pilot/pod versus the wing drag ? (the old Rogallo "tuck dive' effect might somehow apply also if the surface aft of the D nose is itself flexible )

    There would appear to be no inherent reason to limit the attainable speed of a flying wing --the first transonic aircraft did not feature tails in fact (DH Swallow, Messeshmitt Komet etc Bell X5 et al ) -- the loss of reflex with forward stick might reduce stability margins somewhat I surmise but don't look like show stoppers --the Kasperwing is no different in this sense than other swept all wings or is it ?

    Returning to the theme of road take off and landing -- and being serious about it ; the concept demands that the vehicle MUST convert 'on the run' both from air to road mode and road mode to air mode since you cannot expect other traffic to stop or slow down for you --and there can be no acceleration on either take off or landing since there are not large gaps at convenient locations to suit a take off roll starting slow and sspeeding up . this imposes certain constraints on the conversion process and the intermediate geometry between modes (for example you could not fold one wing in or out at a time --it would just roll over . Neither can the wing be allowed to rotate along the spanwise axis (in pitch ) and least of all be broadside to the airstream --many otherwise feasible conversion systems fail these tests .

    Neither could the wing extend into the space used by vehicles in adjacent lanes --perhaps being much higher than anything else could qualify but that tends to be susceptible to blow over --the turbulence created by bluff vehicles in front is also a problem (as it is with the aerodynamics of race cars --losing downforce from the upwash of the rear airfoil of the car in front )

    Palmer Stiles intended his CarNard to deploy it's wings underway (on a roadway) and to retract them also after landing at highway speeds -- probably being envisioned to only happen way out of busy sections of roads though. Maybe Ken Wernicke thought this was possible for his 'street legal' width Aircar as well (it was never finished and found it's way to a museum in England somehow --it is not unusual for flying cars to dissappear after the designer becomes aware of some oversight after construction.

    If a valid case can be made for RTOL then it could be done here --it is a definable 'extra' operational mode from the others already nominated and it is clear that not all are convinced of the infeasibility (or concomitantly of the feasibility of ATOL or VTOL for that matter )-- if nothing else the old adage "a man convinced against his will is of the same opinion still " comes to mind . In terms of patentability the concept of "obviousness" is crucial and yet very hard to define --real life examples as shown by reactions on this thread can well constitute evidence .

    the comment before about crash survivability and the need for "bull bars" (also known as Roo bars or Boong bars over here to bounce various forms of wildlife off when encountered on the road ,usually at night ) is also not a joke -- cars have to be designed by law for impact unlike aircraft . The Smithsonian book of flight ends with a 'vision of the future' including Paul Mac Cready on solar powered and soaring ultralights and the almost incredible statement " future use of new composite fibres will allow an aircraft to fly into a concrete wall at crusing speed without injury to the pilot " (a close approximation without having it at hand -- I can copy the exact words if disputed ) I find this just about in-credible. But might be needed for RTOL .
     
  2. Sep 18, 2013 #1602

    Holden

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  3. Sep 18, 2013 #1603

    henryk

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    AIRCRAFT WING WITH VORTEX GENERATION

    http://koendu.pl/doc/KASPAIR 200 Preliminary Specifications.pdf

    -Vlanding=35 mph
    -Vmax=300 mph...not bad!

    BTW=I see,it is possible to made KASPAIR200 foldable wings =avery wing devided on the thri 2-meter panels,TERRAFUGIA like,but opposite direction\high wing\.
     
    Last edited: Sep 18, 2013
  4. Sep 18, 2013 #1604

    Holden

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  5. Sep 18, 2013 #1605

    Aviator168

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  6. Sep 18, 2013 #1606

    WonderousMountain

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    You must learn to use the separation bubble to your advantage, only then will you be able to land like cherry blossom:ponder:
     
  7. Sep 18, 2013 #1607

    henryk

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  8. Sep 19, 2013 #1608

    Aircar

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    Holden I only just saw your #1600 post and #1604 (after posting on the new RTOL(r) thread ) --if the activity on RTOL (R) keeps up I will be able to retire just on the royalties from use of the term RTOL(r)

    Henryk -- Have you or your accomplices done any flow testing (tufting even) to check out Kasper's theorized flow structure ? - I know that SAAB could not reproduce his expected flow field -- Kasper also hypothesized that the flow through the tip feathers of birds was reversed , whether his theory was right is not so important as that the wing works of course which it appears to (Brochoki apparently didn't concur about the reason for high Cl ) In the fifties a lecturer at Sydney University tested a forward facing vortex flap called ,after him, a "batchelor" flap it was hinged at the trailing edge and opened up from about 2/3 of the chord as I recall --it was intended to be the reattachment point for a vortex nested ahead of it and must have been amongst the first to propose separated flow lift (although Lawrence Hargrave actually drew his concept of a lower side nested vortex in 1880s papers to the Royal Society )
     
  9. Sep 19, 2013 #1609

    Holden

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    If I remember correctly YOU asked me to use it and therefore gave me permission to use it without cost. :gig: I appreciate that.
     
  10. Sep 19, 2013 #1610

    henryk

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    -bis now we have not vortex fenomena flow testings,
    but I hope=after first "normal" fly testing auer BEKAS it shold be moora advanced tests,aspatially=vortex flow regime!

    -I think=SAAB tunnel test was made on the rectengular wing,not sweep\13-20 degrees\ wing!

    BTW=first "ROADABLE"!
    https://www.youtube.com/watch?v=Wwovm1FJ_Bo
     
  11. Sep 22, 2013 #1611

    Holden

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    Let's see if we can get this thread to end...so we can start a new one that is shorter and up to date.

    so, NO MORE POSTS...
     
  12. Sep 22, 2013 #1612

    henryk

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  13. Sep 22, 2013 #1613

    Aviator168

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    What do they attach on top?
     
  14. Sep 22, 2013 #1614

    WonderousMountain

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    Fabric can be stored in a different manner than wings using solid structures.
     
  15. Sep 22, 2013 #1615

    henryk

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    =parawing\flexible\.
    FLYCAR

    =FLYCARII=2place,1=100HP HONDA engine...
     
  16. Sep 22, 2013 #1616

    marketmerlin

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    I don't know why but I get the feeling your a Dr Who fan :)
     
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  17. Sep 23, 2013 #1617

    henryk

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  18. Sep 24, 2013 #1618

    Aviator168

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    henryk, that's one more way to scam investor money as the flapping fan is never going to work. Even if they manage to some lift out of the wing, that fan is going to break. I respect you posting information here; but hey, can you post something that actually works. If you want to make something that blows air across the wing, take a look at fanwing, which at least actually flies.
     
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  19. Sep 24, 2013 #1619

    Holden

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    And how does this become roadable, which is the point of this thread? Please explain.
     
  20. Sep 24, 2013 #1620

    Aircar

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    Fair go ! Henryk is posting what looks like properly conducted research and seems to have a base of scientific results -- at least give him the courtesy of a respectful hearing and forgo the insinuations. It should be obvious as to what such a technology has to offer roadability --anything that can reduce the size and bulk (volume) of a wing to create the same lift makes the attainment of a reasonably sized road package so much easier . Conversely ,the ability to fly slower makes the take off and landing runs shorter and thus opens up more options for places to get into and out of the air -- both the oversize of the 'folded/stowed ,or otherwise converted for road use, vehicle and the limitations of long runways way out of town have been show stoppers for the near entirety of previous attempts at a viable flying car --solving these issues is at the very heart of the problem.

    The noise and vibration of the test set up might be drawbacks but not necessarily show stoppers if only existing for the last few seconds of flight --it is clear that the oscillating flap could be easily stopped and remain in place without being any great burden for the aircraft in cruise --unlike some of the other attempts at a stopped rotor or the many failed pumped boundary layer (eg Sikorsky X wing ) or such schemes .

    From the simulation it looks like a vortex is formed with each oscillation which then drifts rearwards over the wing (with three in the length of the chord ) so it is like a travelling wave as against a standing wave -- if this indeed does result in the very high Cls shown on test data then it is well worth exploring .

    One thing that stands out in most of the earlier flying car designs is the LACK of appreciation for the value of higher Cls on reducing the size of the flying surfaces and thence the road package -look at Molt Taylor's Aerocar for a good example (not even plain flaps to shrink the wing - the road size is a flying semi trailer rather than a car ) the Fulton airphibian, Convaircar, Terrafugia, Brown Carplane et all all exhibit this oversight.

    Please don't be put off by the criticism Henryk.
     
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