Dick, list:
you make some good points, Dick J. However, I think where Wes is coming
from is that (at our intended high speeds) centrifugal force tries to expand
the tire carcass to failure (even on our inflated tires). And rubber does
not have a very high yield strength in tension. The thinner the tire
(especially in the tread area), the less mass centrifugal force has to work
with-- so the less force is generated to pull the tire carcass apart. (I
assume that's why the SCTA rules up-rate a tire's speed if the tread has
been "shaved".)
Even with the very thin MT landspeed tires, we sometimes hear rumors of fast
cars whose tires have "grown" irreversibly during a run. It has been
proposed that perhaps centrifugal force has simply stretched the rubber past
the elastic limit. (The calculation to prove/disprove this would be easy--
except that we don't know the range of elastic modulus for the MT tire
rubber-- or how it might change with age, etc.)
It seems to me that solid rubber tires (of any thickness over 1/8", or so)
would be likely to magnify this problem-- they would grow and probably
"chunk" (due to the same centrifugal forces), unless you make them a
"composite" structure, with metal or fiber reinforcement throughout, to
provide adequate tensile resistance to the centrifugal force.
Russ
-----Original Message-----
From: owner-land-speed@autox.team.net
[mailto:owner-land-speed@autox.team.net]On Behalf Of Dick J
Sent: Saturday, August 24, 2002 8:59 PM
To: W S Potter; autox list
Subject: Re: Solid Rubber tires?
Is rotating weight always bad? Why some heavy steel flywheels and some
light aluminum flywheels. Wouldn't heavy rotating tires carry momentum?
Wouldn't they be smoother over small surface imperfections in the track?
Dick J
W S Potter wrote:Rotating weight!
Wes
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