Engines > Your Own Design
Rotary Valve Engine
crueby:
--- Quote from: PaulR on May 14, 2025, 10:34:46 PM ---
--- Quote from: crueby on May 14, 2025, 09:33:50 PM ---A flywheel ought to get it past the dead spots till the next power stroke. :popcorn: :popcorn: :popcorn:
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Thanks Chris. I was also thinking an o-ring on the piston might help given that it's single acting, I need to read up on how to use them and whether the drag will offset any benefit.
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I use viton rings on all mine, a bit of trial and error to get the depth of the groove just right, but they seal really well with vety little drag, given a drop of oil. Would be worth the experiment. For a single cylinder single ac5ing, you might need a bit more flywheel.
Jasonb:
If you can Simulate the valve action correctly in your CAD then it should be OK, I've only used that type of valve with eccentrics.
Regarding the cross head, why not do away with that piston rod and clevis and run the conrod straight to the piston with a wrist pin much like an IC engine. Having a longer piston will also help keep things lined up, it does not matter if the piston comes out beyond the end of the cylinder.
On such a small bore I would just run the piston without rings and cut a couple of oil grooves. The drag from a ring is not going to help get you over centre.
PaulR:
--- Quote from: crueby on May 14, 2025, 10:54:31 PM ---I use viton rings on all mine, a bit of trial and error to get the depth of the groove just right, but they seal really well with vety little drag, given a drop of oil. Would be worth the experiment. For a single cylinder single ac5ing, you might need a bit more flywheel.
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:ThumbsUp:
PaulR:
--- Quote from: Jasonb on May 15, 2025, 07:01:52 AM ---Regarding the cross head, why not do away with that piston rod and clevis and run the conrod straight to the piston with a wrist pin much like an IC engine. Having a longer piston will also help keep things lined up, it does not matter if the piston comes out beyond the end of the cylinder.
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Thanks Jason. That was the original plan but it has a knock on effect - either the crank has to be further away, the bore/cylinder bigger or the conrod smaller. If it was a 'bucket' type piston I'd probably have to make it longer anyway. I'll have a ponder while I'm denied workshop time due to decorating :(
Zephyrin:
the choice of the o'ring is easily made with a complete set of 1/10 mm drills or equivalent, (which you probably have, only up to 10mm in my case): by placing the ring on the drill shank and and by inserting it in the bore, the finding the optimum depth of the groove to be machined is easy.
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