So I am thinking of a little engine, I suppose one really should build a little oscillator engine as a first engine but the Artful Bodger is never one to follow custom and common sense.
I am thinking of a steam (air actually) engine with piston ported valving using a technique someone must have used before but I have never seen described. What I have in mind is a piston with a very deep skirt on the top side that will act as a sleeve valve. As the piston moves it will open input and exhaust ports. The feature that will (might?) make it interesting is that the piston will both reciprocate (that is, move back and forth) and will also partly rotate about its axis, sort of twisting one way then the other about 70 degrees or so. The rotation of the piston will be caused by having the crank pin inclined in relation to the crankshaft axis and the connecting rod will have Hook's joints at each end. Having the piston partially rotate in this way means that a point on the surface of the piston will prescribe an eliptical path and I can drill the ports to give a suitable duration of input and exhaust openings.
So far I have made a cylinder and started to turn the piston though that is quite difficult requiring a small boreing bar that I dont dont have as yet, I need to turn a fairly deep 22mm into the head of the piston and that will form the sleeve.
So far I am thinking of steel for piston cylinder etc.
There is a long way to go on this one and I am currently travelling on the Mainland for a couple of weeks.
Cheers
John
a.k.a The Artful Bodger