On
5 June 2025 at 11:14 JasonB Said:
Another method, for anyone who wants to experiment would be a slide valve operated by a pivoted lever and a face cam on the crankshaft./
See my reply above yours and the link to the original No1 MTB with it’s face cam.
Westbury did the Gemini high speed steam engine which had a gear driven rotary valve, Gray Meek did his own designs inspired by the Gemini which use a toothed belt.
ETW used to do a column in ME called ‘Utility Steam Engines’. One of them was a single acting twin with a bevel gear drive to a vertical shaft between the cylinders and a flat rotary valve on top, bit like the 3 cylinder radial whose name escapes me.
Cylindrical rotary valves seem to be the holy grail of steam engines, the Paget loco built by the Midland Railway, wasn’t all that successful. If you make the clearance twixt valve and sleeve too small it seizes up, too big and it leaks like a sieve. Gray is clearly one of those demi-gods who can achieve such accuracy. I once worked with a chap who had worked for Roland? Cross on rotary valve IC engines. He reckoned when they got the oil consumption lower than the fuel consumption they were doing well.
Bill Hall was working on a vee 4 with semi rotary valve similar to Corliss when he died, somewhat easier to get it to seal.