🚀 go-pugleaf

todamhyp@unlv.edu (Brian M. Huey) writes:

>I realize this a relatively basic question (I think) nevertheless:

>	I am neither a pilot nor an airliner engineer. However,
>everytime I watch a airliner land, a cloud of smoke is produced when
>the wheels come in contact from the ground due to friction. Couldn't
>this cloud and the effect of friction be lessened by inducing a
>angular velocity upon the wheels to match the airliners speed with
>respect to the runway?

This has been tried.  It did reduce tire wear, but it did cause
some problems.  How would you like to try landing a 747 with a
bunch of gyroscopes attached?  It adversely affects handling qualities
of the aircraft.  :-)

In article <1992Dec18.180933.15387@unlv.edu> todamhyp@unlv.edu (Brian M. Huey) writes:
>I realize this a relatively basic question (I think) nevertheless:
>
>	I am neither a pilot nor an airliner engineer. However,
>everytime I watch a airliner land, a cloud of smoke is produced when
>the wheels come in contact from the ground due to friction. Couldn't
>this cloud and the effect of friction be lessened by inducing a
>angular velocity upon the wheels to match the airliners speed with
>respect to the runway?
>
    Back a while ago (fifties or sixties?) tires were available with radial
pockets which were to perform that function.  I believe they fell into dis-
use because they didn't turn the tire fast enough (whacking a tire turning
50 mph onto a runway at 100 mph isn't much improvement over one that isn't 
turning).  Also, they would have been nasty to recap, a big factor in tire
design for the airlines.

    Rubber is considered a consumable, just like fuel.  There are a lot of
other factors which limit a tire's life--braking heat to mention one.

    That's a good observation, though.  I'm glad somebody questions the
validity of that movie cliche.

J. Matthews
Standard Disclaimers Apply

todamhyp@unlv.edu (Brian M. Huey) writes:
>	I am neither a pilot nor an airliner engineer. However,
>everytime I watch a airliner land, a cloud of smoke is produced when
>the wheels come in contact from the ground due to friction. Couldn't
>this cloud and the effect of friction be lessened by inducing a
>angular velocity upon the wheels to match the airliners speed with
>respect to the runway?

Interestingly, this was the first suggestion that I submitted when I
started working for Boeing, even though I'm a computer weenie rather
than an aero weenie.  I suggested it to be motor driven or "wind
vanes". 

It was turned down (of course).  The explanation was that the weight
for the system (and complexity) wouldn't be worth it.  



-- 
Michael Bain                                            (206) 234-6942
Boeing Commercial Airplane Group           meb4593@icdfs.ca.boeing.com
Seattle, WA 98124

meb4593@galileo.rtn.ca.boeing.com (Michael Bain) writes:

--- Suggestion made to spin tires prior to touchdown to reduce tire wear--

>Interestingly, this was the first suggestion that I submitted when I
>started working for Boeing, even though I'm a computer weenie rather
>than an aero weenie.  I suggested it to be motor driven or "wind
>vanes". 

>It was turned down (of course).  The explanation was that the weight
>for the system (and complexity) wouldn't be worth it.  

Another reason not to do it is that the purpose of landing is to
stop the airplane. If you spin up the tires, more braking must be
done to stop the plane. Recapping tires is cheaper than replacing
brakes.

 

--------------------------------------------------------------------------
|      Philip Bridges                 |  "Strive for design simplicity:  |
|      Dept. of Aerospace Eng.        |   you never have to fix anything |
|      Miss. State University         |   you leave out."                |
|      (601) 325-3623                 |                                  |
|      pdb1@ra.msstate.edu            |           Bill Lear (1903-1978)  |
--------------------------------------------------------------------------

In <1281@galileo.rtn.ca.boeing.com> meb4593@galileo.rtn.ca.boeing.com (Michael Bain) writes:

>todamhyp@unlv.edu (Brian M. Huey) writes:
>>	I am neither a pilot nor an airliner engineer. However,
>>everytime I watch a airliner land, a cloud of smoke is produced when
>>the wheels come in contact from the ground due to friction. Couldn't
>>this cloud and the effect of friction be lessened by inducing a
>>angular velocity upon the wheels to match the airliners speed with
>>respect to the runway?

>Interestingly, this was the first suggestion that I submitted when I
>started working for Boeing, even though I'm a computer weenie rather
>than an aero weenie.  I suggested it to be motor driven or "wind
>vanes". 

>It was turned down (of course).  The explanation was that the weight
>for the system (and complexity) wouldn't be worth it.  

Guess they don't have to pay for the tires. Note to Layne Cook, I
have tried twice to e-mail you regarding my earlier post on this
thread, but both bounced. The gist of my message was that like
Michael, I'm a computer/communications weenie not an aero weenie.
Actually, we use the term propellor-head here, which might seem
apt :-).

I guess that the electric motor idea won't fly because it would
displace the brake mechanism. Even though they use wheel mounted
motors on electric autos, they still have room for inboard brakes.
This would be just a bit difficult on a 747 or 1011, let alone a
Cessna 172.


>-- 
>Michael Bain                                            (206) 234-6942
>Boeing Commercial Airplane Group           meb4593@icdfs.ca.boeing.com
>Seattle, WA 98124

Bob, who has absolutely nothing to do with aircraft and still can't
find the plans for his RC Beech Staggerwing :-(.

In article <bob1.726264511@cos> bob1@cos.com (Bob Blackshaw) writes:
>In <1281@galileo.rtn.ca.boeing.com> meb4593@galileo.rtn.ca.boeing.com (Michael Bain) writes:
>
>>todamhyp@unlv.edu (Brian M. Huey) writes:
>>>	I am neither a pilot nor an airliner engineer. However,
>>>everytime I watch a airliner land, a cloud of smoke is produced when
>>>the wheels come in contact from the ground due to friction. Couldn't
>>>this cloud and the effect of friction be lessened by inducing a
>>>angular velocity upon the wheels to match the airliners speed with
>>>respect to the runway?
>

	On the other hand anyone can burn out a set of tires on one landing.
	Almost.

	A friend went out for a Sat flight. I was sunny and warmish. During
	taxiing he used his brakes a bit, taxiied through some slush. Went
	flying, at landing he received a bit of a shock when the main gear
	were locked solid. He slid for a ways one tire broke loose, and
	the other tire started rolling shortly after. (Luckily)

	Though the tires didn't pop, he had to trash them as they had a 
	serious flat spot.

	NOW he recalls that you shouldn't use brakes or taxii through
	slush.


	Doug Bloomberg  doug@alliant.com (Ol' Alliant is going Tango Uniform
					  in a week or so I will be off the
					  net till a new job comes along.
					  Between resumes maybe I can get
					  some work done on the RV.)

In article meb4593@galileo.rtn.ca.boeing.com (Michael Bain) writes:
>
> --- Suggestion made to spin tires prior to touchdown to reduce tire wear--
>
>>Interestingly, this was the first suggestion that I submitted when I
>>started working for Boeing, even though I'm a computer weenie rather
>>than an aero weenie.  I suggested it to be motor driven or "wind
>>vanes".
>
..

In fact this is done on some aircraft, eg. Cessna Citation as part of the
"gravel kit" option.  The main advantage is significantly reduced braking
distance, I believe.  (I don't have my notes here, but from memory, bleed
air is used to achieve the spin-up just prior to landing.)

Tom Nemeth