Hi
I had mentioned I was building a rotary valve engine based on the 'River Queen' plans. Well I have now had the first run out of it so here are a few details and a couple of pictures.
To my way of thinking the valve design for the River Queen was not correct, only allowing opening of both inlet and outlet to the cylinder for 90 degrees of rotation. My design allows opening for 180 degrees, below is my childish sanity check model, the purple being the groove on the valve for air inlet and the blue for the exhaust. I think I managed to get a slight overlap which makes the exhaust sound quite distinctive.
I made the valve a force fit on the shaft and turned it to diameter when the shaft was in the lathe collet to ensure concentricity. I also put the groove in almost the middle of the valve to have the longest leak path to reduce leaks. I managed to get a lapped fit and air leakage seems negligible though I left enough room either side of the groove for O rings as a back up plan.
The piston was machined for an O ring but none fitted and it runs well without.
I used a taper lock for the flywheel fixing, a first for me and I am pleased how it has turned out as I was worried about a wobble creeping in.
I will now build a base for it so I can take the air inlet pipe down underneath the base and out to the end for the air connection which I think is less obtrusive.
A clip of it running will follow soon.
