Author Topic: Piston Stroke to Bore ratio for steam Engine  (Read 2668 times)

Offline Baron

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Piston Stroke to Bore ratio for steam Engine
« on: March 23, 2014, 04:43:46 PM »
Hi Guys,
What would be the best piston stroke to bore ratio for a double acting stationary steam engine ?
I am thinking of using a cast iron cylinder with a 20 mm bore but have no idea what length to make it for optimum performance.

Thanks:


Best Regards:  Baron.

I donít regret the things Iíve done, I regret the things I didnít do when I had the chance.

Offline Tin Falcon

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Re: Piston Stroke to Bore ratio for steam Engine
« Reply #1 on: March 23, 2014, 07:38:27 PM »
There are lots of stationary engine designs. 
Depends on if you want the engine to run fast or slow.
1:1 ratio or square as it is called is IMHO the most common.
so 20 mm bore 20 mm stroke  or 10 mm ctc crank shaft center to crank pin center.
if you are building a waling beam they tend to have a longer stroke in the 1:1.25 to 1:1.5 range.
Tin

Offline sbwhart

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Re: Piston Stroke to Bore ratio for steam Engine
« Reply #2 on: March 23, 2014, 07:52:38 PM »
Small engines tend to run fast so I  usually use a 2-1 or 2.5-1 ratio boreu 20mm stroke 40 or bore 20mm stroke 50mm

Stew
A little bit of clearance never got in the way

Offline Baron

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Re: Piston Stroke to Bore ratio for steam Engine
« Reply #3 on: March 23, 2014, 08:46:27 PM »
Hi Tin, Stew,

Thanks for your reply's.

So based on your suggestions, if I go for a stroke length of 30 mm with a 5 mm thick piston I shouldn't be too far out.

I'm thinking marine type engine here with four cylinders.

Best Regards:  Baron.

I donít regret the things Iíve done, I regret the things I didnít do when I had the chance.