Lifting body + prone position ?

Discussion in 'Hangar Flying' started by Retroflyer_S, Sep 27, 2015.

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  1. Sep 27, 2015 #1

    Retroflyer_S

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    I just figured the most effective aeroplane concept.

    Or is it somehow dubious ?
     
  2. Sep 27, 2015 #2

    BJC

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  3. Sep 27, 2015 #3

    Aerowerx

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    Not a new idea. Many of the early Horten wings were like that

    Horton-Glider-with-skid.jpg

    This would have the lowest profile drag, compared to an upright seated position.
     
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  4. Sep 27, 2015 #4

    WonderousMountain

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    I think if you have comparable surface area to say, a 103 ultralight, it would be a very interesting proposal.

    LuPi
     
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  5. Sep 27, 2015 #5

    RPM314

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    Maybe something like a mini F4D Skyray with a higher AR, where the pilot's legs go back into the blended section, with an ICE in the back....
     
  6. Sep 27, 2015 #6

    TFF

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    Northrop has a prone plane and the pilots did not like the ground coming up to them, made them feel like they were going to crash.
     
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  7. Sep 27, 2015 #7

    RPM314

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    Well that's their problem.

    No but really, that's just the result of trying to acclimate to a new position. If prone was the standard and someone built a sitting plane *gasp*, pilots would probably say it made them feel like the plane's attitude looked all wrong, that it was too hard to gauge distance to the ground when touching down, complain about terrible over-the-nose visibility, etc.
     
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  8. Sep 27, 2015 #8

    markaeric

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    I wonder about how comfortable that position would be. I'd imagine you'd want something to assist with holding your head.
     
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  9. Sep 27, 2015 #9

    RPM314

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    Yes, somebody linked to a 3rd party flight evaluation of a prone position Horten glider recently in another thread, I'll try to dredge it up later. The pilot reported that a chin rest was essential for flying more than 5-10 minutes, though I don't think there were any comments about neck and back comfort aside from that. I'd say turn your couch into a mock cockpit (mockpit?) with a bunch of pillows to see if it works for you.
     
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  10. Sep 27, 2015 #10

    FritzW

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  11. Sep 28, 2015 #11

    Aesquire

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    That is exactly true. Hang gliders are mostly flown prone. I've flown prone, seated, and supine, ( reclined ) and much prefer supine for flights of any length. Visibility straight down & forward is superb prone, not so great supine, but since there is no fuselage, looking past your legs is no big deal, and all positions land standing up. ( in fact, standing up and speeding up is the drag brake mode for lowering L/D ) Hang Glider pilots tend to have very well developed neck muscles from holding the head up.

    Comfort prone is an issue. Pressure on rib cage, abdomen, and crotch are problems. A classic Prone harness, before the era of streamlined pods, held you up by a wide, padded belt around the hips, straps around each leg, with shoulder straps. ( and a chest strap to keep the shoulder straps from spreading. In car seat terms, 6 point, not 5. This rapidly evolved into a hammock supporting from the shoulders to just below the hip. Still 6 point.

    You need a sturdy harness, well attached to the frame, to keep from sliding forward in a hard landing. Any structure in front of you can be deadly. No structure in front of you is deadly. A chin support is very nice, but is also a decapitation device....

    It's not that Prone is not practical. It's that it's different.
     
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  12. Sep 28, 2015 #12

    Victor Bravo

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    1) Find the most aerodynamically efficient aircraft type in common usage that you can.

    2) Find the type of (small, private) aircraft that routinely does the longest flights.

    3) Find the type of (small, private) aircraft that requires the largest amount of constant strategic and tactical decision-making by the pilot, over the longest period of time per flight (which thus would require the greatest amount of pilot comfort over time to allow such effective decision-making).

    4) Find the type of (small, private) aircraft that has had the greatest time and effort of design engineering, research and testing, from most all of the world's leading technical universities, and which aircraft type has consistently attracted the best and brightest minds in all of aviation.

    Congratulations, you have just discovered competition sailplane racing.

    Now take a look at the pilot seating position that is used in this sport, that allows all of the above to happen :)
     
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  13. Sep 28, 2015 #13

    Sockmonkey

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    IIRC you have to be a bit more careful in control placement relative to the pilot. Done right, they're as comfortable as a standard layout. Done wrong it's much more aggravating than a poorly done standard layout would be.
     
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  14. Sep 28, 2015 #14

    Retroflyer_S

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    Thanks for all the outstanding comments and opinions.

    Now back to the drawing board.
     
  15. Sep 28, 2015 #15

    Retroflyer_S

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    Gliders ( as sailplanes ) are not lifting bodies..just the contrary.
     
  16. Sep 28, 2015 #16

    bmcj

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    Nothing discussed here so far is what I would consider a lifting body. So far, it has all been flying wings. Generally lifting bodies are short, bulbous, and wingless. The bulbous shape can house a seated pilot easily... no need for prone position.
     
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  17. Sep 28, 2015 #17

    Retroflyer_S

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    If you want a smallish ( affordable ) plane to be really efficent the chord of the lifting body ( element ) cannot be thicker than 12-15 %, so you cannot sit inside of it.
     
  18. Sep 28, 2015 #18

    StarJar

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    Blended body?
     
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  19. Sep 28, 2015 #19

    Retroflyer_S

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    Yes I mean a blended body design with a sorta lifting body element.

    Happy we got the terms right. Aeroplane needs wings.
     
  20. Sep 28, 2015 #20

    Victor Bravo

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    Effective for what?

    It is absolutely dubious because (in my opinion) the true lifting body is the very least efficient aerodynamic configuration of any flying machine. The government and the military can afford to use this configuration if it were necessary, but commercial aviation and certainly private aviation cannot afford this. The lifting body was invented and tested as a way to return astronauts to the ground in an environment where wings are too easy to damage or break or burn up. But the lifting body is so inefficient that it was worth the effort to put wings on the Space Shuttle, despite having to solve the heat and structure problems.

    All homebuilders are operating their aircraft where re-entry from space is not an issue (sorry Burt... almost all homebuilders). So the one and only real aerodynamic advantage of a lifting body is not present.

    What we're left with that is relevant is the cost of fuel, the amount of power needed for level flight, the distance for takeoff and landing, and the amount of training necessary for the target pilot population to be competent. None of these factors favors or even tolerates the true lifting body.

    The blended wing/body configuration is different, and is potntially relevant to homebuilders as Barnaby Wainfan's Facetmobile has demonstrated. But tis is nowhere near a "lifting body" like the HL-10 and M2-F2 NASA programs.

    The Facetmobile proved to be far more efficient than anticipated, and there are very important advantages that this type of configuration could possibly deliver to general aviation.
     
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