G'day All,

I'm suffering from a terminology problem - I see it bandied about quite a bit on the internet as well as here on the forum.

What do people mean when they say that a flywheel (for example) is neutrally balanced?

Are they talking about it being what I call statically balanced?


My understanding is that a rotating something is statically balanced when it favours no particular point in its rotation.

For example you hold the rotating onject in one position - let it go and it won't move to another more favourable position. Hold it in another position and let then let it go and it won't move back to that favourable position.

So you could also spin it - evil friction slows it - and it stops at one point. Spin it again - evil friction slows it - and it stops at another different point...

...statistically speaking if you were to mark your rotating object with 360 equal degrees the chances of it falling between two points should be 1/360 => it shouldn't favour a particular point like a dodgy roulette wheel.


Or has it got something to do with how the rotating parts have been balanced? I've seen several references on 'internet that talk about internal and external balancing where external balancing is adding weight on the outside of something (like balancing a tyre - you add weights to correct for the any uneven thickness in the rubber or the valve stem weight) and internal is material removal somewhere inside. These terms seem to get included with the term "neutrally balanced"...

See for example

Pro-race


Surely it doesn't have anything to do with dynamic balancing???


I haven't found a source of information that defines this term. Can someone help?

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!