Re: Tire burn-out during landings

From:         wolfgang@trout.nosc.mil (Lewis E. Wolfgang)
Organization: NCCOSC, NRaD Division
Date:         29 Dec 92 22:53:45 PST
References:   1
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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