Piston diameter?

Parthe said:

Bit of an odd question but what’s the diameter of a Rocket 3 piston?

2.3 or 2.5 will be fine, the measurement will be close enough for my needs.

“Why?” I hear you ask. Well because I want to make three gavels from them, obviously. Now aren’t you sorry you asked?

I’ve tried Google but it’s failed me.

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R-III-R Turbo said:

101.6mm (Rocket III)
110.2mm (Rocket 3)

It should be a filter question when signing up to the site!

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Mongler07 said:

You can easily come up with some basic math.
Most engines run a fairly square stroke to bore. So it's just a volume calculation.
Volume of a cylinder is V=πr2h
So
(2300/3) = 3.14r2h
So basically for the sake of your question h = 2r
I'm too lazy past this point so I checked it in wolframalpha and it came up with basically 101.1 but that's close enough for your whatever reason I assume.
Math is free online. Learn how to use it.
Beefy 4 inch piston

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Parthe said:

Mathematics is freely taught in schools where I grew up and I’m very good at basic maths, but I learned volume calculations a very long time ago and I can’t work out how I would get the diameter even with your example. This is how far I got:
2300 = the engine size and it’s a three cylinder, hence (2300/3). Call it 800 for this example.

800 = 3.14r2h or 254.77 = r^2 * h

That leaves two unknown numbers, r and h but I have no idea how I’d work that out.

> So basically for the sake of your question h = 2r

I have no idea how you made this leap. Where would I get that information from?

I’m genuinely interested in how the mathematics works here.

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Mongler07 said:

IDK, it was very early in the am. you can't figure that this way. I already knew the stroke so in my going to bed minds just assumed you could.

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Parthe said:

Bit of an odd question but what’s the diameter of a Rocket 3 piston?

2.3 or 2.5 will be fine, the measurement will be close enough for my needs.

“Why?” I hear you ask. Well because I want to make three gavels from them, obviously. Now aren’t you sorry you asked?

I’ve tried Google but it’s failed me.

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Parthe said:

OK, with thanks to everyone who responded. I was always told to show my working out so for future querants:

Formula for working out the volume of a cylinder: is V=πr2h

Rocket III	Rocket 3
Volume: 2300	Volume: 2500
Stroke (Height): 101.6mm	Stroke (Height): 110.2mm
3.142 * r^2 * 101.6 = 2300	3.142 * r^2 * 110.2 = 2500
3.142 * r^2 = 22.638	3.142 * r^2 = 22.686
r^2 = 7.205	r^2 = 7.220
r = 2.684	r = 2.687
diameter = 5.37cm	diameter = 5.374cm

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