Hi Tom, I suspect the rough running is due to the new rotary valve.
There would be a squeal, a puff of steam from the valve and a shudder in the engine. My guess is the moving parts in the valve are trying to seize, being broken free by the engine torque, deforming, opening gaps and releasing steam. The leaking steam drops the pressure to some of the cylinders and causes the engine to 'misfire' on those cylinders.
Bearing in mind that there is no load on the engine, there is only enough steam being supplied to it to overcome internal friction, i.e., not very much. A little steam leakage would be enough to slow the engine.
The Ohio State University redesign of the WHE engine added a rotary valve. Maybe Harry is trying to use this on the Mark 5 to at least be able to demonstrate a Mark 5 running. Running, sort of.
Even with no load, low pressure and temperature steam, the rotary valve is in distress. A hundred horsepower of 3200 psi 1200F steam won't be tolerated for long by this valve.
What's Harry thinking? He now seems to be building a slightly larger WHE engine: low pressure, low temperature, low power and low efficiency. Yet another change of course for the Mark 5.
Maybe Frankie will tell him to stop playing with diversions, and deliver on his promises of a working Mark 5... ;)
