Honda-SOHC

Other Stuff => Misc / Open => Topic started by: McCabe-Thiele (Ted) on December 04, 2024, 05:06:09 AM

Title: A bit of useless information from FB - is it real or fake?
Post by: McCabe-Thiele (Ted) on December 04, 2024, 05:06:09 AM
Are these figures real?(https://live.staticflickr.com/65535/54181352677_ce66a57c22_o.jpg) (https://flic.kr/p/2qxPAv4)468781476_8855112764553890_7028269928070594777_n (https://flic.kr/p/2qxPAv4) by Macabe Thiele (https://www.flickr.com/photos/187487200@N03/), on Flickr

Title: Re: A bit of useless information from FB - is it real or fake?
Post by: K2-K6 on December 04, 2024, 08:21:10 AM
Possibly I think  :)

While I (think  :) ) I understand the forces and direction, I'm nowhere near in knowledge of how to calculate them.

Effectively a wheel is stationary at the bottom when vehicle is moving (else you'd observe slip at the road surface) and so nil movement,  then at 150mph it would be travelling in direction of vehicle at 300mph over the top and opposite the base.

That could accommodate this effect as I see it. Acceleration from 0g up to peak and back again. 

That would only be for the point at maximum circumference though (I think) as the spindle of the wheel would be @ the notional 150mph, with a gradient downward to contact patch diminishing, but the opposite accumulative.  Depending where the valve sits in that scheme would dictate tge Acceleration equation.

In my view  ;D
Title: Re: A bit of useless information from FB - is it real or fake?
Post by: McCabe-Thiele (Ted) on December 04, 2024, 09:42:11 AM
We probably all remember from applied maths  Force=Mass x Acceleration, the figures do not give the diameter of the wheel at the valve fitting relative to the center of the axle so not easy to check quickly.
Preumably some backwards calculation would arrive at an answer for the 0 to 300mph if it was all calculated in metric.




Title: Re: A bit of useless information from FB - is it real or fake?
Post by: Sesman on December 04, 2024, 09:48:43 AM
F=mw2r. So yes it’s true. The ‘2’ is wsquared.  W=2pif. Eg angular velocity.

Long hand: force = mass x angular velocity squared x radius. I’ve used this in the past to calculate rotational forces on large machine windings. It’s one of the reasons why we shift from Low voltage to high voltage on electrical generators when we get to a critical kw size: say around 2MVA. ( the force on the copper windings is immense). It’s also why three phase induction motors spin at relatively low revolutions. Eg frequency divided by pole pairs.
Title: Re: A bit of useless information from FB - is it real or fake?
Post by: ST1100 on December 04, 2024, 11:54:53 AM
Tried to explain this to folks who insist on installing their (heavy) aftermarket TPMS dust-caps...  ::)
Title: Re: A bit of useless information from FB - is it real or fake?
Post by: Johnny4428 on December 04, 2024, 12:03:21 PM
Wow guys never even considered this! 😳
Title: Re: A bit of useless information from FB - is it real or fake?
Post by: McCabe-Thiele (Ted) on December 04, 2024, 12:05:42 PM
If the aftermarket one fell off at 40 mph it would hurt if it struck a pedestrian.

As you know the cheaper TPS systems fitted to cars use wheel slippage from the ABS wheel sensors. Our old 2005 Jeep WK showed  all four actual tyre pressures in psi, plus unusually if the spare wheel went flat it said check spare on the dash. The spare was never fitted in the 6 or so years we owned it, the warning would come up about every 12-18 months due to rim seal leak I guess, whatever battery it had was never replaced
Title: Re: A bit of useless information from FB - is it real or fake?
Post by: Athame57 on December 04, 2024, 12:26:34 PM
If the aftermarket one fell off at 40 mph it would hurt if it struck a pedestrian.
I've got classic metal ones myself, but I've never known one to go astray. Surely stone chip is the way to shoot pedestrians on the move? 8) 
(https://www.oxfordmail.co.uk/resources/images/1333665.jpg?type=mds-article-962)
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