Lifting body + prone position ?

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

Help Support HomeBuiltAirplanes Forum by donating:

  1. Sep 29, 2015 #41

    BJC

    BJC

    BJC

    Well-Known Member HBA Supporter

    Joined:
    Oct 7, 2013
    Messages:
    9,732
    Likes Received:
    6,515
    Location:
    97FL, Florida, USA

    DZ:

    Get out of your fantasy zone, and get you feet back on the ground. :)


    BJC
     
  2. Sep 29, 2015 #42

    RPM314

    RPM314

    RPM314

    Well-Known Member

    Joined:
    Mar 27, 2015
    Messages:
    724
    Likes Received:
    302
    Location:
    NY, USA
    Well if it required gettin' busy in the prone position where cardiovascular effects could cause a catastrophic sexyness failure and crash the bed into terra firma at 250kts...
     
  3. Sep 29, 2015 #43

    Retroflyer_S

    Retroflyer_S

    Retroflyer_S

    Banned

    Joined:
    Nov 3, 2014
    Messages:
    411
    Likes Received:
    29
    Location:
    Michigan
    Folks ahoy !

    Let's not turn it into a mid-air sex experience thing.

    More and more people are also driving velomobiles instead of bikes.
     
  4. Sep 29, 2015 #44

    DangerZone

    DangerZone

    DangerZone

    Well-Known Member HBA Supporter

    Joined:
    Sep 5, 2011
    Messages:
    2,107
    Likes Received:
    370
    Location:
    Zagreb HR
    I said 'well designed', not 'flawed beyond repair'... :gig:

    Kidding aside, there was a moderately well designed prone homebuilt aircraft that anyone could make in their garage: the Wee Bee. :)

    20559d1352315989-hi-everyone-spain-628x471.jpg

    WeeBee3view_A.jpg

    A bit too big, too underpowered and too slow for my taste, but we gotta admit that it was well designed for that era. ;)
     
    RPM314 and Retroflyer_S like this.
  5. Sep 29, 2015 #45

    Retroflyer_S

    Retroflyer_S

    Retroflyer_S

    Banned

    Joined:
    Nov 3, 2014
    Messages:
    411
    Likes Received:
    29
    Location:
    Michigan
    This is a good question...I was thinking myself, why would I leave the fun for someone else ?


    The size thing is a good question too. I was thinking a 15 m x 7 m twin motorglider...that can obtain 10 000 meters altitude and cruise ( there ) 200 kts using 2 x 10 hp engines.
     
    Last edited: Sep 29, 2015
    WonderousMountain and DangerZone like this.
  6. Sep 29, 2015 #46

    Retroflyer_S

    Retroflyer_S

    Retroflyer_S

    Banned

    Joined:
    Nov 3, 2014
    Messages:
    411
    Likes Received:
    29
    Location:
    Michigan
    It could be either electric or piston ac...but ( extremely ) efficient.
     
  7. Sep 29, 2015 #47

    DangerZone

    DangerZone

    DangerZone

    Well-Known Member HBA Supporter

    Joined:
    Sep 5, 2011
    Messages:
    2,107
    Likes Received:
    370
    Location:
    Zagreb HR
    Exactly, why leave the fun to someone else..? :) We usually even have some expenses when flying (fuel) compared to flying 'for free'... ;)

    The mentioned wing size is a bit... large. Remember Felix Baumgartner, the man who first flew across The Channel with his carbon fiber wing? His wingspan was 1.9m and he developed speeds of 200kts at altitudes slightly below 9000m.
    _39345371_base_jumper_inf416.gif

    It would be wise to keep the wingspan below 2.5m for subsonic wingbodies, this is the limit for international road transport (2.55m). Thus the wing can be built in one piece and transported on the roof of your car. If you position it upright you might get some funny looks and questions about the 'alien UFO' that 'caught' your car's roof. To avoid this simply invert the thing and put some cover on it. When asked by people what is it - deny it is an aircraft. You can always say it's a kid's toy and that it's purpose is for childr playing. Try doing that with a 15m wingspan and you definitely won't get away with it. :D

    The engines of 2x10HP might be underpowered even for larger wingspans. The Lazair flies better with two 20HP to 30HP engines, this shortens the takeoff and allows better climb. However, if you are building a glider intended for long soaring then it might be wise to try yourself if the prone position is that comfortable for you.
     
    Retroflyer_S likes this.
  8. Sep 29, 2015 #48

    DangerZone

    DangerZone

    DangerZone

    Well-Known Member HBA Supporter

    Joined:
    Sep 5, 2011
    Messages:
    2,107
    Likes Received:
    370
    Location:
    Zagreb HR
    ... Double post.
     
  9. Sep 29, 2015 #49

    Retroflyer_S

    Retroflyer_S

    Retroflyer_S

    Banned

    Joined:
    Nov 3, 2014
    Messages:
    411
    Likes Received:
    29
    Location:
    Michigan

    I could have different set of wings and engine variations for the need.

    High soaring low power ( 20-30 hp ) and low flying short span ( 50-100 hp ).

    Sinus has 80 hp and 15 m span ( does 250 km/t ), but Zenair 100 hp and 8 m ( does only 140 km/t ).

    I remember Helios went 275 km/t ( ground speed ) and weighed 750 kg but had only 28 kW at 100 000 ft.
     
    Last edited: Sep 29, 2015
  10. Sep 29, 2015 #50

    Doggzilla

    Doggzilla

    Doggzilla

    Well-Known Member HBA Supporter

    Joined:
    Jun 2, 2013
    Messages:
    1,963
    Likes Received:
    413
    Location:
    Everywhere USA
    I always wanted to build something like this. But they really need to learn how to optimize something like this. They could be much more practical.
     
    DangerZone and Retroflyer_S like this.
  11. Sep 29, 2015 #51

    Retroflyer_S

    Retroflyer_S

    Retroflyer_S

    Banned

    Joined:
    Nov 3, 2014
    Messages:
    411
    Likes Received:
    29
    Location:
    Michigan
    I have seen these creatures for a pretty long time now and they seemed to have been able to optimize some flying devices. There are hundreds of subtypes of these around. :gig:
     

    Attached Files:

  12. Sep 29, 2015 #52

    DangerZone

    DangerZone

    DangerZone

    Well-Known Member HBA Supporter

    Joined:
    Sep 5, 2011
    Messages:
    2,107
    Likes Received:
    370
    Location:
    Zagreb HR
    They could have made an effort and built a better one. James Bond movies allways showed some advanced high tech vehicles and this one looks like a tin can.

    [video=youtube;2MGGcT4xlq0]http://www.youtube.com/watch?v=2MGGcT4xlq0[/video]
     
    Last edited by a moderator: Mar 20, 2019
  13. Sep 29, 2015 #53

    Retroflyer_S

    Retroflyer_S

    Retroflyer_S

    Banned

    Joined:
    Nov 3, 2014
    Messages:
    411
    Likes Received:
    29
    Location:
    Michigan
    That is the prone position all right.

    Now you have to study the Vincent Burnelli and Bill Horton to know more about the lifting bodies.

    Seems that the term is " lifting fuselage " that I am after ( more or less ).

    http://the-things-with-wings.blogspot.fi/p/burnelli-lifting-fuselage.html
     
    Last edited by a moderator: Mar 20, 2019
  14. Sep 29, 2015 #54

    Retroflyer_S

    Retroflyer_S

    Retroflyer_S

    Banned

    Joined:
    Nov 3, 2014
    Messages:
    411
    Likes Received:
    29
    Location:
    Michigan

    Attached Files:

  15. Sep 29, 2015 #55

    bmcj

    bmcj

    bmcj

    Well-Known Member HBA Supporter

    Joined:
    Apr 10, 2007
    Messages:
    12,971
    Likes Received:
    4,915
    Location:
    Fresno, California
    But that is skydiving where your primary focus is the ground below you (if it's above you, you did something wrong :gig:). You can crane your neck to look out horizontally and a little bit above you, but to sustain that head angle for sustained horizontal flight has got to be strenuous.
     
  16. Sep 29, 2015 #56

    Retroflyer_S

    Retroflyer_S

    Retroflyer_S

    Banned

    Joined:
    Nov 3, 2014
    Messages:
    411
    Likes Received:
    29
    Location:
    Michigan
    Can't you look at the meters/gauges every now and then ? Do you have took forward all the time ?

    -----

    Why are these always so boxy...any other lifting body/fuselage form out there ?
     

    Attached Files:

  17. Sep 29, 2015 #57

    WonderousMountain

    WonderousMountain

    WonderousMountain

    Well-Known Member

    Joined:
    Apr 10, 2010
    Messages:
    1,853
    Likes Received:
    193
    Location:
    Clatsop, Or
    Oh yes, there are all sorts of lifting/blended bodies. We who have been on this site a while have a truly wonderful history of images (if we can remember them),

    and in some cases performance stats.

    The question you raised is a problem in design. Rounding the edges causes a large loss in lift, as air slides off the rounded sides and to the top. That said, the boxy is a large source of drag. More to the point, any large airfoil like surface will work for a Cl of about 1.

    Maybe it's time to do some serious research into what you want.
    I'd love to see where it takes you.

    LuPi
     
    Retroflyer_S likes this.
  18. Sep 29, 2015 #58

    DangerZone

    DangerZone

    DangerZone

    Well-Known Member HBA Supporter

    Joined:
    Sep 5, 2011
    Messages:
    2,107
    Likes Received:
    370
    Location:
    Zagreb HR
    Actually, you DON'T want your body to create lift like an airfoil because it would create more drag than if not having lift. You want WINGS to create lift and the faster the aircraft flies the lower the induced drag. Thus the goal is to get parasitic/form/wetted-area/friction drag to a minimum and have as small wings as possible for the lift needed in your mission requirements.

    This kind of thinking was also the obvious problem with the Phasst: it had less lift and more drag than the Gryphon which had a smaller wingspan and less wing surface area. The V stabilizer is in the wake of the whole body so it has poor authority, this was a very common problem of most 'lifting body' aircraft. Finally, such a concept of low control, lift, performance and efficiency is simply a problem waiting to become a disaster.

    The ideal form with least drag is the Haack-Sears body. This is why there were many airplane fuselages which mimick this form and use wings to provide good lift for both high and low speeds. That's the biggest challenge, to find a good wing form and form adjustment technique which would allow both.
     
    bmcj and Retroflyer_S like this.
  19. Sep 29, 2015 #59

    bmcj

    bmcj

    bmcj

    Well-Known Member HBA Supporter

    Joined:
    Apr 10, 2007
    Messages:
    12,971
    Likes Received:
    4,915
    Location:
    Fresno, California
    Nothing boxy about this...

    Martin_Marietta_X-24A.jpg

    (More potato-ey than boxy :gig:)
     
    Retroflyer_S likes this.
  20. Sep 29, 2015 #60

    Retroflyer_S

    Retroflyer_S

    Retroflyer_S

    Banned

    Joined:
    Nov 3, 2014
    Messages:
    411
    Likes Received:
    29
    Location:
    Michigan
    Ok.

    Here is my attempt.

    :whistle:
     

    Attached Files:

Share This Page



arrow_white