Newsgroups: sci.aeronautics.airliners Path: news From: wolfgang@trout.nosc.mil (Lewis E. Wolfgang) Subject: Re: Tire burn-out during landings X-Submission-Date: Tue, 29 Dec 1992 19:45:12 GMT References: Message-ID: Approved: kls@ohare.Chicago.COM Reply-To: wolfgang@trout.nosc.mil Organization: NCCOSC, NRaD Division Sender: kls@ohare.Chicago.COM X-Submission-Message-Id: <1992Dec29.194512.10054@nosc.mil> Date: 29 Dec 92 22:53:45 PST In article 194@ohare.Chicago.COM, rdd@cactus.org (Robert Dorsett) writes: >Strictly speaking, I don't see this as a gyroscopic effect. We're just >talking about the rotational momentum set up by a spinning tire, and what to >do about it. (Stuff deleted) > > (3) the *additional* wear and tear on the brakes, as they >must absorb the spinning energy, in addition to performing their normal >task of slowing down the airplane. >(3) seems the major disqualifier of the idea. With an inert tire, you'll >have *minor* control problems ("bump", and that's it), but the energy absorbed >by the tire in *spinning up*, on landing, in itself helps slow the airplane. >That smoke's the energy being absorbed by the tire. If the tire's already up >to landing speed, I can easily see landing distances lengthened considerably. (lots more stuff deleted) Robert, I think you have your mass off by several orders of magnitude. If the mass of the rotating tires is insignificant compared to the total mass of the airframe (to negate the gyroscopic effect) then it will contribute negligibly to the stopping distance. Consider, if you will, when the pilot manages to "grease" one on: no noticeable deceleration is observe at the moment of touchdown. There may be a vertical "bump", but not a horizontal one. (if there is no crosswind component) IMHO you would see no measurable difference in rollout distance or residual heat in the brake system. Luck Lewie wolfgang@nosc.mil