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I understand this question is broad, but specifically referencing modern jets where composites are used a lot to get complex surfaces (such as in the Beechcraft Premier 1), how much of the total lift is generated by the fuselage versus the wings, perhaps as a percentage of total lift? The fuselage is obviously a lifting body and I’ve noticed the same in other current designs.

Premier 1 src Wikipedia

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  • $\begingroup$ This question is too general and there are too many unanswered variables to answer this question. $\endgroup$ – jwzumwalt Jan 26 '18 at 5:03
  • $\begingroup$ I would be happy with a “generally from x% to x% if such a figure is known by any designers around here. $\endgroup$ – Pugz Jan 26 '18 at 5:11
  • $\begingroup$ A close approximation is to take the wing lift using the general lift formula (CL for the airfoil, wing area, angle of attack). Subtract wing lift from aircraft weight, equals amount fuselage is lifting. i.e. if aircraft weighs 10,000lbs and CL wing lift = 9500lb, then everything else (mostly fuselage - but some engine) is 500lbs. $\endgroup$ – jwzumwalt Jan 26 '18 at 5:33
  • $\begingroup$ I have run the numbers for small aircraft like C150 or C172 and my recollection was the fuselage and engine provided about 5-7% lift. However in aerodynamics school we ran numbers for the T33 and I think the fuselage could provide all the necessary lift at about 350kts - so speed matters. A B727 doubles it's wing area in the landing configuration, showing the wings on an airliner are really only needed for landing and takeoff! $\endgroup$ – jwzumwalt Jan 26 '18 at 5:44
  • $\begingroup$ @jwzumwalt, wings are needed for producing lift efficiently. Lifting bodies only make sense at hypersonic speeds. $\endgroup$ – Jan Hudec Jan 26 '18 at 19:17
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Not as much as potentially possible. This thread lists the numbers for some common aircraft and should give you a general idea, it seems to be ~10%

747:

  • Wings: 89.5%
  • Fuselage: 13.1%
  • Horizontal Tail: -3.7%
  • Vertical Tail: .1%
  • Nacelles and Pylons: 1%

P-51D:

  • Wings: 92.9%
  • Fuselage: 7.7%
  • Horizontal Tail: -.7%
  • Vertical Tail: .1%

I belive the center bulge on the bottom is also there to allow for a floor recess in the cabin making it easier to get around.

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  • $\begingroup$ It's not as much as potentially possible, because it is a really bad idea. You only want to create fraction of lift that a little over the fraction of its width to wingspan. Producing more lift with fuselage is inefficient due to its low aspect ratio (except at supersonic speeds where the lift-related lift is tiny fraction of the overall drag). $\endgroup$ – Jan Hudec Jan 26 '18 at 19:21
  • $\begingroup$ @JanHudec How does this apply to high Mach number operations where most of these modern business jets cruise (Mach 0.8 to 0.9)? Wouldn’t it become more efficient in the transsonic region? $\endgroup$ – Pugz Jan 28 '18 at 2:11
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    $\begingroup$ @Pugz, no. The aircraft cruise just below their drag divergence speed, that is before significant effect of wave drag, so the subsonic relation between induced and form drag applies. And note that at the altitude, the cruise speed is just something like 250–270 knots indicated and calls for rather high aspect ratio (usually over 9). $\endgroup$ – Jan Hudec Jan 28 '18 at 11:33

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