Lifting body + prone position ?

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

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  1. Sep 30, 2015 #81

    Retroflyer_S

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    Ok I won't start arguing with this, but I hope you will someday understand that a meter high fuse vs ½ meter high fuse ( prone ) has less drag...anyway you look at it.

    Also all fuselages have lift...some are just called lifting fuselages for some reason.
     
  2. Sep 30, 2015 #82

    WonderousMountain

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    I think you're confusing 2 different types of planes.

    The "All wing", and the lifting body.

    Very different character. We had a discussion about focusing too much on frontal area,

    for low drag you need smooth skin, smooth area distribution, no gaps, etc.

    You can't just fly approach at 25 degrees, your wing will stall and you'll crash.

    It's not a bad concept, but there's no outsmarting phenomena, gotta work with it to get results.

    LuPi
     
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  3. Sep 30, 2015 #83

    Topaz

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    It's entirely possible that a fuselage with a prone pilot position may have less parasite drag. However, there are a lot of other considerations that go into designing an airplane, which makes it a giant series of compromises. Pilot comfort can't be dismissed - the poor guy actually has to be comfortable enough to fly the aircraft for the entire design mission.

    What we were talking about earlier was doing a Burnelli-style wing-section fuselage, as you had in your earlier sketch. While it seems intuitive that such a fuselage would reduce drag, since it "takes over" some of the wing's load, the low aspect ratio of such a fuselage "stub wing" means that overall drag will go up, particularly at low speeds. Induced drag is the dominant form at low speeds.
     
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  4. Sep 30, 2015 #84

    Retroflyer_S

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    I couldn't agree more with you...you nailed it.

    I have shown you just one possible lifting body ( that was created in the 70ies ) as an application for a homebuilt. I want to have twin with 15 m span and 7 m lenght just like I mentioned in the beginning of this thread.

    It is the crystallized aeroplane version of this;
     

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  5. Sep 30, 2015 #85

    Doggzilla

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    The main problem with flying wings is that the CG and center of lift arent aligned, so a lot of induced drag is caused by having to TRIM to keep the nose in the air. With weight shift, the weight is hanging and will center under the point its hanging from. So there is a lot less induce drag from trim. Most prone flying wings have the face where the load would be on most large flying wings, so the body is significantly further back. The fuselage section extends much further back to envelope the prone person, and the CG is much closer to center instead of up front.

    If you take a quick look at a B-2, youll notice that most of the weight is in the front half of the aircraft. The wings are swept back and away from any load. Then look at a horten, and youll see that the fuselage extends back further and the person's center of weight is closer to the halfway point of the wing root. Which is near the center of lift.

    Most of the additional drag on a flying wing is caused by the induced drag from trim.
     
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  6. Sep 30, 2015 #86

    WonderousMountain

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    Well, I'm confused.

    Best of luck.
     
  7. Sep 30, 2015 #87

    RPM314

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    When designing the flying wing, you would pick the static margin you want, pick the pilot's position, and arrange the fuse and wings such that you hit the CG target. For a single place sportplane, lying prone tends to make it easier to get that CG because the pilot is a significant portion of the plane's mass and flipping his torso to the front shifts that mass forwards. For a sitting or supine position the fuse will have to be further forwards relative to the wing is all. So whether prone is an advantage for CG considerations depends on the particular configuration of the plane.
     
  8. Sep 30, 2015 #88

    Topaz

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    Well said.
     
  9. Oct 1, 2015 #89

    Retroflyer_S

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    I could make it at 10 m x 5 m size too. I may reconsider the size once the R/C model flies first. Goal is to set around 10 new FAI records.
     
  10. Oct 1, 2015 #90

    WonderousMountain

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    It's out of my league,

    you've got some imagination, if you buckle down and get some qualified help, it may work.
     
  11. Oct 1, 2015 #91

    RPM314

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    :D

    Oh, one concrete advantage prone would have is that if you have a pusher engine (as tailless planes are wont to do), having that torso forwards will increase the moment of inertia in pitch, delaying the onset of BFF and/or letting you save spar weight due to the reduction.
     
  12. Oct 1, 2015 #92

    henryk

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  13. Oct 1, 2015 #93

    DangerZone

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    Like the O'Neil PeaPod..? :D

    peapodoneil_500x293.jpg
     
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  14. Oct 1, 2015 #94

    RPM314

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    I'd imagine that plane just scares flutter away by virtue of its looks, not any mechanical property.
     
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  15. Oct 1, 2015 #95

    Aesquire

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    Best way imho to do prone is with a harness to support the torso, a heel bar for the feet, and rudder pedals underneath.

    The solid contact points are foot bar, knee pads and elbow rests. Clear canopy leading edge.

    Suspend the pilot from shoulders & hips. Emergency egress is by quick release buckles, harness mounted single handle. ( Booth style 3 ring ) Which has a 2 stage pull. First stage releases you from airframe. Second opens chute.

    I'm assuming you have no problems with crawling under the plane to squirm into the cockpit through spring loaded bomb bay doors.

    That's with solid structure over the pilot and little below. If you want to put the structure underneath, you have to have a swing away canopy, crawl over the wing and in. The over pilot strong back from shoulder to hip w /harness allows a completely smooth top surface and is lighter.

    Prone is doable. Not simpler.
     
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  16. Oct 1, 2015 #96

    Retroflyer_S

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    Ok.

    My ego might be writing checks my body cannot cash !
     
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  17. Oct 2, 2015 #97

    Retroflyer_S

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    Is there an other picture of this ?
     
  18. Oct 2, 2015 #98

    billyvray

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    Mr. Oneill used to be a contributor on here but I don't recall seeing responses in a while.

    That thing looks like one hell of a ride!

    Bill
     
  19. Oct 2, 2015 #99

    DangerZone

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    Did it ever fly..?
     
  20. Oct 2, 2015 #100

    RPM314

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    I have no doubt. It would have scared the ground away by virtue of its looks.
     

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