newtons law.

john robert bould · Dec 28, 2012

Newton found that for every action there is a equal and oposite re-action, So..
When the crank is subject to a rapid change in force..ie on the firing stroke. where will the oposite reaction act?

grandpaul · Dec 28, 2012

Mainly at the crank's noses, I would think...

ntst8 · Dec 28, 2012

The driving force is the heat induced increase in pressure in the combustion chamber - uniform pressure in all directions if considered statically - so that is more or less balanced depending on how significant dynamics effects are.
The actions/reactions which need to be dealt with are due to the acceleration/deceleration of the moving parts or out of balance rotation of parts.
All partially catered for via crank balance factor - the rest working its way out of the system via vibration.
The force driving the piston is converted to (or resisted by) a torque on the crankshaft, ultimately resisted via wind resistance and other friction losses.

Matt Spencer · Dec 28, 2012

I thought it lifted the front wheel .

Hobot · Dec 28, 2012

Iain and matt got it right, the combustion heats the nitrogen which expands-pushes on all surfaces but the piston side can give downward most so the engine head and what's attached to it jumps up, somewhat if rubber mounted. It becomes clear when engine is run in weightlessness unmounted.

Rohan · Dec 28, 2012

Ever notice that when you drop the clutch and apply throttle, the bike accelerates down the road.
Thats the reaction of the bike to the force applied to the rear wheel, via the rubber, onto the tarmac.

Funny about that....

Rohan · Dec 28, 2012

hobot said:
Iain and matt got it right, the combustion heats the nitrogen which expands-pushes on all surfaces but the piston side can give downward most so the engine head and what's attached to it jumps up, somewhat if rubber mounted. It becomes clear when engine is run in weightlessness unmounted.

It doesn't even have to be weightless.
An engine tested on an engine dyno can measure the deflection against a spring to give you the applied torque - this is the simplest dynamometer.

Borrowed this pic off someones electric train discussion...

Hortons Norton · Dec 28, 2012

Handlebars! :wink:

ILLF8ED · Dec 29, 2012

Rohan said:
Ever notice that when you drop the clutch and apply throttle, the bike accelerates down the road.
Thats the reaction of the bike to the force applied to the rear wheel, via the rubber, onto the tarmac.

Funny about that....

And the opposite reaction is the road which is connected to the planet moves with equal force in the opposite direction of the motorcycle. Brings up the question if all the vehicles on the planet drove westward at the same time would it slow the rotation of earth.

sidreilley · Dec 29, 2012

john robert bould said:
Newton found that for every action there is a equal and oposite re-action, So..
When the crank is subject to a rapid change in force..ie on the firing stroke. where will the oposite reaction act?

John, An interesting discussion but I just curious why you asked the question in the first place. :wink:

john robert bould · Dec 29, 2012

I have been reading the post's regarding balance, i think the subject is interesting, the crank must be subjected to many force's as each cylinder acts upon the crank at differant times.
Compression on one side,exhaust on the other, then firing on one and the other filling, slowing down and then suddenly speeding up,,the rotary norton was a great effort in elimantion of these primitive actions...well the internal combustion engine was developed over 150 years ago. But it is simple and reliaible ,grand prix cars reving to 20,000 rpm , say's it all.....it works and works dam well!

sidreilley said:
john robert bould said:

Newton found that for every action there is a equal and oposite re-action, So..
When the crank is subject to a rapid change in force..ie on the firing stroke. where will the oposite reaction act?

Click to expand...

John, An interesting discussion but I just curious why you asked the question in the first place. :wink:

comnoz · Dec 29, 2012

Any thing that moves, gets hot or makes noise and is not directly pushing the bike down the road is wasting power.

A 100% efficient engine would be smooth, silent and would radiate no heat. Jim

john robert bould · Dec 29, 2012

100% , as a Commando is approx 20% or lower[converting fuel into motive force] ,,there's a long way to go :!:

quote="comnoz"]Any thing that moves, gets hot or makes noise and is not directly pushing the bike down the road is wasting power.

A 100% efficient engine would be smooth, silent and would radiate no heat. Jim[/quote]

Hobot · Dec 29, 2012

Yep taking in the big picture scope of energy reactions form combustion heat on molecule speed-pressure, the final counter reaction is the Earth. With the current level of Earth monitoring I'd bet if most the worlds craft all aimmed against planet rotation it could be measured. They can measure the effect of wind and water flow-tides on rotation rates slowing and speeding, some what like crank pulses.

Jim to measure the engine recoil from combustion stroke the whole engine would have to have some freedom of movement, by support in gravity field via spring, air balloon, liquid or free fall, otherwise their recoil is taken up by support rigidity into the mass of its foundation into the Earths crust. The elastic and dampening nature of crust would stimmy measuring Earth recoil to a Norton Twin. Yes you could measure the compression/rarification waves in the crust but that's not recoil of balk mass just the jiggles that self cancel in polarity till dissipated as heat.

I swear there is something to the isolastics that helps power pulse traction, but of course must operate in traction limits of various sorts to detect this. My ponder is how the BF affects this on the recoil loading of two iso rubbers in line of thrust with tire rubber hysteria.

Dances with Shrapnel · Dec 29, 2012

Too much caffeine today?

comnoz · Dec 29, 2012

Dances with Shrapnel said:
Too much caffeine today?

I think I need about 5 more pots of coffee before I can read it.

john robert bould · Dec 29, 2012

Just what i was thinking steve. Stephen Hawkins where are you when i need you!

hobot said:
Yep taking in the big picture scope of energy reactions form combustion heat on molecule speed-pressure, the final counter reaction is the Earth. With the current level of Earth monitoring I'd bet if most the worlds craft all aimmed against planet rotation it could be measured. They can measure the effect of wind and water flow-tides on rotation rates slowing and speeding, some what like crank pulses.

Jim to measure the engine recoil from combustion stroke the whole engine would have to have some freedom of movement, by support in gravity field via spring, air balloon, liquid or free fall, otherwise their recoil is taken up by support rigidity into the mass of its foundation into the Earths crust. The elastic and dampening nature of crust would stimmy measuring Earth recoil to a Norton Twin. Yes you could measure the compression/rarification waves in the crust but that's not recoil of balk mass just the jiggles that self cancel in polarity till dissipated as heat.

I swear there is something to the isolastics that helps power pulse traction, but of course must operate in traction limits of various sorts to detect this. My ponder is how the BF affects this on the recoil loading of two iso rubbers in line of thrust with tire rubber hysteria.

lcrken · Dec 29, 2012

If anyone really wants a good read on the fundamentals of engine balance and forces, read Chapter 8 of Charles Taylor's "The Internal Combustion Engine in Theory and Practice, Volume 2: Combustion, Fuels, Materials, Design, Revised Edition" from 1985. It and its companion Volume 1 were published in a reasonably priced paperback edition by the MIT Press, and I assume it is still available somewhere. The set is a must have for anyone serious about understanding IC engines, and is worth having just for its extensive list of references. I'm sure it's already part of the library of some of the more technically oriented listers here.

Internal and external forces in IC engines, at least to any level we are interested in, has been well understood for a long time. This is not new science.

Ken

john robert bould · Dec 29, 2012

Here is my totaly insane idea, or is it?
Bond the flywheel to the crank with rubber, ford use this idea on the crank damper.
Without this two piece rubber damper the crank breaks,it's purpose is to damp out the destructive flexing..would a commando crank be improved with this idea?
Back to the sherry

lcrken · Dec 29, 2012

john robert bould said:
Here is my totaly insane idea, or is it?
Bond the flywheel to the crank with rubber, ford use this idea on the crank damper.
Without this two piece rubber damper the crank breaks,it's purpose is to damp out the destructive flexing..would a commando crank be improved with this idea?
Back to the sherry

Good sherry, I hope?

The bonded rubber crankshaft damper used by Ford et. al. are meant to reduce torsional vibrations in the longer crankshafts in auto engines, but do nothing for bending forces. I suspect that Commando cranks are fatigued at the mainshaft base primarily because of bending stress, not torsional, so bonding the flywheel with rubber wouldn't do much for that particular problem. Just my humble opinion, though.

Ken

newtons law.

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