Re: [Phys-L] Explaining Gyro Force to Motorcyclists

[bnorwood111@gmail.com]

Hi phys-L guys,

Back when I was 18 in the 1950’s, I bought a Harley-Davidson Sportster, a motorcycle way overpowered for my experience. 

I knew nothing about gyroscopes, and did not realize that I should know.
Same for my father who rode an Indian motorcycle, with the square-4 engine, in the 1920’s.

I got out on the highway and overtook a car which was doing about 50 mph, and whipped my motorcycle back in front of the car, either because of an oncoming car or because of stupidity or both.

That’s when the wild oscillations in the handlebars started. (I also did not know anything about motorcycle steering damping, despite a high school physics course.)

I held on for dear life, and I guess that the forces of my arms on the handlebars served as damping, and I was able to bring the motorcycle under control.

If I had gone down in front of that car it would have been all over for me - I would not have been alive to report on an experience I did not understand, and it was unlikely that the car driver knew anything at all about gyroscopic forces and motorcycles, so, statistically, the gyroscope-related accident never happened. 

That would distort any statistics about what percentage of motorcycle deaths are due to rider ignorance or unawareness of gyroscopic forces on motorcycle steering. 

I think that John Denker gets it right when he writes that the most effective way to teach about gyroscopic forces is to attach a couple of handles to the axle of a bicycle wheel, hand it to the student, give it a spin and instruct the student to deflect it. That way the student gets to unforgettably feel the gyroscopic force and its direction.

And thanks to Brian Whatcott for guiding me to a relevant journal article.

BACKDROP:

I just got reminded of the preciousness of life when, on Jan 06, 2022, I lost both my brother, 82, and his son, 56. (not motorcycle-related)

Bill Norwood 
U of MD at College Park
1966 - 2018



Sent from my iPhone

> On Jan 14, 2022, at 2:40 PM, Brian Whatcott <betwys1@sbcglobal.net> wrote:
>
> I expect Bill has in mind the counter steer or sometimes counter lean used to improve the time delay for onset of turning. The wiki article or really articles - "Bicycle and motorcycle dynamics" which offers one hundred elevent references to the literature, https://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics
>
>
> and "Countersteering" https://en.wikipedia.org/wiki/Countersteering
> offer notes on this method of avoiding obstacles when moving fast.Both gyroscopic effects and trail of the front fork have been over-emphasized in the past in connection with steering - which effects are now  largely discounted.
> Brian W
>
>  - Bill Norwood via Phys-l <phys-l@mail.phys-l.org>UnsubscribeTo:phys-l@mail.phys-l.orgCc:bnorwood111@gmail.com,ericn6561@gmail.comFri, Jan 14 at 11:41 AMHi all,   
>
> I need a list of references about how the gyroscopic force presents a hazard for uninformed motorcycle riders.   
>
> My guess is that motorcycle deaths could be reduced by 25% if the riders were aware of the gyroscopic force hazard.   
>
> Bill Norwood   
> U of MD at College Park   
> 1965 - 2018
>
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