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Vertical Take Off

  1. Feb 1, 2016 #1
    Why can't we adopt Vertical Take Off (VTO) and vertical landing in commercial aircraft?
     
  2. jcsd
  3. Feb 1, 2016 #2

    russ_watters

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    Commercial aircraft have very low power to weight ratios. Putting in bigger engines or engines that don't work as well at high speed is a trade-off that isn't worth it.
     
  4. Feb 1, 2016 #3
    Umm... can u imagine flood recovery aircraft..? It can take off and land during flood
     
  5. Feb 1, 2016 #4

    SteamKing

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    That's not an application for a commercial aircraft, though.

    They already have aircraft which can land and take off during floods - they're called helicopters. :wink:
     
  6. Feb 1, 2016 #5

    billy_joule

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    Why would comercial (ie long haul) aircraft be used in flooded areas? What advantage does it have over helicopters (Or Osprey I guess)?

    131762216_21n.jpg

    Can you imagine doing this with a VTOL 747? The Rescuee would be cooked to a crisp in the jetblast :nb)
     
  7. Feb 2, 2016 #6
    But think about airplanes in a flooded airport
     
  8. Feb 2, 2016 #7

    billy_joule

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    I'd guess the percentage of all commercial flights that are grounded due to runway flooding is around 0.0001% ie totally inconsequential, or do you have evidence to the contrary?
    Even if it where a problem the obvious, and cheapest solution would be better airport design.

    Why not calculate how many more engines a 747 would require for VTO? Do you think it's a viable aircraft design?
     
  9. Feb 2, 2016 #8

    SteamKing

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    If the airplanes at a flooded airport didn't take off before the flood, then there's something wrong besides the planes not being VTOL capable.
     
  10. Feb 3, 2016 #9
    You mean the below?
    6a011168586588970c0134863486d3970c-pi.jpg
     
  11. Feb 3, 2016 #10
    This is an amphibian aircraft so it can land and take off from water...but what about this below pic.
     
  12. Feb 3, 2016 #11
     

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  13. Feb 3, 2016 #12

    russ_watters

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    Airports are designed not to flood, so if they do it must be due to a rare/significant natural disaster. It doesn't make sense to design commercial airplanes to operate in such rare/extreme conditions. Heck, if the airport is flooded, the passengers can't get there anyway!
     
  14. Feb 4, 2016 #13
    They aren't practical in the sense that for a large aircraft to have VTO and landing capability the engine thrust has to be scaled up enormously, they'd have to carry more fuel they would weigh more so their payload capability would be limited. Even tilt wing and tilt rotor aircraft have an upper limit on lift capacity (power to weight). We do have aircraft called air cranes which have a larger lifting capacity (these are basically helicopters) designed and propose built to lift heavy loads. But even if you could modify one to carry passengers you wouldn't have the speed the range or the altitude of any traditional aircraft design.
     
  15. Feb 4, 2016 #14
    Just to give you an Idea of the thrust involved to achieving VTOL in a jet aircraft here are the numbers


    Harrier Jump Jet, power to weight


    Thrust

    15,000 lbf (66.7 kN)

    21,800 lbf (97.0 kN)

    21,800 lbf (97.0 kN)

    24,750 lbf (110 kN)

    23,500 lbf (105 kN)



    Maximum take-off weight
    (short takeoff)


    17,000 lb (7,710 kg)

    26,000 lb (11,800 kg)

    26,200 lb (11,900 kg)

    31,000 lb (14,100 kg)

    31,000 lb (14,100 kg)



    F135 VTOL raptor power to weight

    Thrust/weight
    • full fuel:
    • 50% fuel:

    0.87
    1.07

    0.90
    1.04

    0.75
    0.91

    F136 is capable of producing more thrust than the 43,000 lbf (190 kN) of early F135s. In testing, the F135 has demonstrated a maximum thrust of over 50,000 lbf






    Max takeoff weight

    70,000 lb class (31,800 kg)

    60,000 lb class (27,300 kg)

    70,000 lb class (31,800 kg)
     
  16. Feb 4, 2016 #15

    Nidum

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  17. Feb 4, 2016 #16

    Nidum

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