(Aero engineer speaking up here) It's the thrust that makes the lift.
The function of the wings and the flaps are to take some portion of the air being blown across the wings (either directly by a propellor or jet engine, or indirectly by the forward motion of the airplane), and turn that flow downwards. By Newton's Third Law, there's an equal-and-opposite upward force on the airplane. This is lift. All that stuff about Bernoulli's Principle is just details on how the flow is turned, feel free to forget about it until you need to do calculations for incompressible fluid flow. A side effect of generating lift this way is generating drag. Some of the energy from the engines is now not being used to move the plane forwards, so it counts as a loss for forward motion. That's drag. More lift means more drag. Flaps are used to generate huge amounts of lift at takeoff, with a corresponding huge increase in drag. The engines need to be big enough to supply enough thrust to still allow the airplane to take off. Now about all those electric motors! One benefit is to be able to smoothly vary the airflow across the entire wing as needed. Another benefit is that, generally speaking, a bunch of small electric motors can be cheaper than an equivalently-powerful large electric motor. Finally, having lots of motors gives you redundancy in case of a failure, which is important in an airplane. Extra costs include the complexity of the control system, the more complicated mechanical design of the wing, and weight and cost of extra wiring. When the engineers who did this design studied the tradeoffs, they must have decided that lots of electric motors were a better idea than just one or two. Et voila, you have the X-57. > On Nov 11, 2019, at 7:54 AM, Peri Hartman via EV <ev@lists.evdl.org> wrote: > > Interesting thought. Does that actually pan out ? After all, that additional > lift takes energy which I think would result in less forward thrust. Not sure > that's a positive tradeoff. > > Peri > > ------ Original Message ------ > From: "Paul Wujek via EV" <ev@lists.evdl.org> > To: ev@lists.evdl.org > Cc: "Paul Wujek" <paul.wu...@gmail.com> > Sent: 11-Nov-19 7:24:41 AM > Subject: Re: [EVDL] EVLN: NASA X-57 Maxwell e-plane w/ 14 e-motors> fly in > 2020 > >> >> On 2019-11-11 10:13 a.m., Peri Hartman via EV wrote: >>> Does anyone know why it is better ? >> >> I'm not an engineer, but I think that having accelerated air from the props >> along the whole length of the wing creates additional lift. >> >> With a single prop the air from the prop would only add lift in the area >> near the fuselage. >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> ARCHIVE: http://www.evdl.org/archive/index.html >> INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) >> > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > ARCHIVE: http://www.evdl.org/archive/index.html > INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) > -- Doug Weathers http://www.gdunge.com "There is no easy way from the Earth to the stars." - Seneca "We choose to go to the Moon and do the other things - not because they are easy, but because they are hard." - John F. Kennedy _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
