WOW Words from a true expert. Thanks for passing that, Rick
Dale C.
-----Original Message-----
From: Rick Hammond [mailto:r.hammond@sympatico.ca]
Sent: Monday, December 10, 2001 10:05 AM
To: land-speed
Subject: Re: MC-CHASSIS-DESIGN -LSR wheels
Hi All,
Here is the reply I got off the MC chassis list; check out Tony's site; he
knows
his stuff.
Cheers,
Rick
Rick asked about;
<<
The question is whether the added gyroscopic effect of heavy wheels would be
an
advantage for a LSR bike, or as with other sorts of competition is it still
better
to have light components?
>>
Cut down on your rotating and unsprung masses as much as possible. The high
speed will give you all and more of the gyro effect that you need.
A high unsprung mass is good for rider comfort when hitting bumps as it
forces the tyre to do the work instead of the suspension and so less shock
reaches the rider. But the price to pay for this is that the tyre suffers
more and endures much greater load variation. It's much better to wear a
kidney belt and stick to light wheels.
A high speed weave is regarded as a castor oscillation of the rear part of
the bike about the steering axis. However, it's effects are not restricted
to the rear alone, a motorcycle is a highly coupled system and the front is
affected also. A large part of this front to rear coupling is due to gyro
effects and so it's a good idea to minimize these as much as possible.
Motorcycles and bicycles have two inherent modes of wobble / weave
instability, 1. an oscillation of the front steered assembly about the
steering axis, normally referred to as wobble, and 2. the rear equivalent as
mentioned above, known as weave. These instabilities are fundamental to the
vehicle type but whether they become a problem on any particular bike
depends on a whole host of factors, damping being an important one. This
isn't just added steering damping, there are many sources of damping in the
system anyway ;- tyres, shocks, rider, there is even hysterisis damping in a
flexing chassis. Too much damping can cause just as many problems as too
little so adding a steering damper is not necessarily the cure in all cases.
Tyre damping of the kind known as yaw damping in the car world will probably
be very different on the salt compared to tarmac and maybe this has a lot to
do with any increased problems experienced in practice on salt. This is
just an idea because I don't have the personal experience to say for sure.
Tony Foale.
Espaqa / Spain
http://www.tonyfoale.com
----------------------------------------------------------------------------
The information transmitted is intended only for the person or entity to
which it is addressed and may contain confidential and/or privileged
material. Any review, retransmission, dissemination or other use of, or
taking of any action in reliance upon, this information by persons or
entities other than the intended recipient or employees of
MD Helicopters, Inc. is prohibited. If you received this in error, please
contact the sender by email and delete the material from any computer..
///
/// land-speed@autox.team.net mailing list
/// To unsubscribe send a plain text message to majordomo@autox.team.net
/// with nothing in it but
///
/// unsubscribe land-speed
///
/// or go to http://www.team.net/cgi-bin/majorcool
///
///
|