Point of mechanical engineering "balance"

the point of engineering balance is a compromise.

its some where in between the point where the accountants gasp and whine about "it cost how much and you want us to pay for that , no way go do it cheaper I dont care if its going to fail early or be a ***** to work on thats not my problem just do it cheaper" and havign the mechanics liberally throw expletives around like punctuation and heartbeats while saying things like " when I find the engineer who designed this pile of rubbish I m going to feed him testicle first into a bench grinder ITs taken me hours of work and I still cant get to the bloody thing to pull it out or off and ITs going to cost a fortune to fix what some dumb ass accountant forced into and the customers going to gripe and whine about the cost because the parts only a few dollars but its " ..........

Mechanic balance is that thing that lets me get home on a push bike after a couple of cans of mechanics lubricant after taking nearly a day to fix something that some engineer failed to balance far enough in my favor when it comes to ease of repair and access.

Amen :mad::p:mad:

(And don't forget the use of unusual fasteners to fit into tiny spaces and their expensive/rare special tools to undo them...)

Quote:

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Originally Posted by Lionelgee

Hello All,

What is the point of balance called when something round and dynamic - such as a car tyre, is put into a "balancing machine" and weights are added to it until it is "balanced". Or in the case of a flywheel metal is removed until the fly wheel is balanced or runs "true". Other than "balanced" or "True" what is the term used in mechanical engineering parlance?

Is it the point of equilibrium? Or is it known by another name? For instance, in the example of a balance beam with two uneven weights located at opposing ends - a pivot can be repositioned under the beam until a point of equilibrium is reached and the beam is horizontal.

What is the term used when a disk is revolving from a central point and the disk is adjusted until it reaches a point of being in balance?

Thanks

Kind Regards
Lionel

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You're not thinking centre of gravity?

What sometimes leads to confusion with balance is "resonance" or the mechanical resonant frequency of a moving mass.

A small example is the balance wheel in a clock, where it is used to advantage to regulate the movement to maintain the time as we known it.

Your Land Rover has an harmonic balancer, which if not working is likely to shake a lot of money out of your pocket!

Big ship marine diesel engines ALWAYS have a certain critical RPM, which if allowed to run at critical speed will rapidly destroy the engine. I am talking about slow speed diesels of around 100 to 120 RPM.

An extreme example of resonance is shown with the video of the Chinook helicopter. The type of rotor system used is prone to "ground resonance", no matter how well balanced the rotor system may be.

Quote:

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Originally Posted by Old Farang

What sometimes leads to confusion with balance is "resonance" or the mechanical resonant frequency of a moving mass.

A small example is the balance wheel in a clock, where it is used to advantage to regulate the movement to maintain the time as we known it.

Your Land Rover has an harmonic balancer, which if not working is likely to shake a lot of money out of your pocket!

Big ship marine diesel engines ALWAYS have a certain critical RPM, which if allowed to run at critical speed will rapidly destroy the engine. I am talking about slow speed diesels of around 100 to 120 RPM.

An extreme example of resonance is shown with the video of the Chinook helicopter. The type of rotor system used is prone to "ground resonance", no matter how well balanced the rotor system may be.

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High speed turbines also have critical speeds that need to be pushed past quickly during startup. They will often have 2 or 3 critical speeds on the way up to opertating speed. A good example of a critical speed is a bench grinder when its running down - starts to reduce speed nice and smoothly, then gets a point where is shakes itself around a fair bit and then smooth off again. Thats a critical speed and occurs when the rotating speed lines up with a resonate frequency - which then amplifies the machines vibration

One of the aircraft types I used to fly (can't remember which one) had the usual band of green ending in a red line on the tacho - with an orange band about 100rpm wide a few hundred rpm below the red line, and a placard warning you not to operate in that band.

Same thing.

John

Quote:

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Originally Posted by JDNSW

One of the aircraft types I used to fly (can't remember which one) had the usual band of green ending in a red line on the tacho - with an orange band about 100rpm wide a few hundred rpm below the red line, and a placard warning you not to operate in that band.

Same thing.

John

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Was it an arrow?

Yes, I think that would be right - an Arrow 180.

John

Quote:

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Originally Posted by JDNSW

Yes, I think that would be right - an Arrow 180.

John

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G'day John & BBD,

One of these ... Accessed February 7, 2016 from,
Piper PA 28R Arrow aircraft history performance and specifications

Kind Regards
Lionel

Quote:

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Originally Posted by Lionelgee

Hello All,

What is the point of balance called when something round and dynamic - such as a car tyre, is put into a "balancing machine" and weights are added to it until it is "balanced". Or in the case of a flywheel metal is removed until the fly wheel is balanced or runs "true". Other than "balanced" or "True" what is the term used in mechanical engineering parlance?

Is it the point of equilibrium? Or is it known by another name? For instance, in the example of a balance beam with two uneven weights located at opposing ends - a pivot can be repositioned under the beam until a point of equilibrium is reached and the beam is horizontal.

What is the term used when a disk is revolving from a central point and the disk is adjusted until it reaches a point of being in balance?

Thanks

Kind Regards
Lionel

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There is a show on paid TV called the science of stupidity If you were to watch a couple of shows I am sure you would pick it up