Rotor with cam plate: rotor seals not shown
When we built the Rumseian Experiment, we tried to decide what to build while we built. That was a mistake. With the rotary engine, we are trying to decide what to build before we build it. Yes, we will very likely have to do some things over, anyway, but at least we can at least catch a few problems beforehand.
Mechanical designer Pete Baker has been helping us. He lead the team that recently created the marvelously lifelike demonstration model of the engine and paddlewheel assembly of Fulton’s first steamboat for the Clermont Historic Site.
With Pete’s gracious help, we got some ideas drawn up on what might be done to modernise the design. Here are a few. The grooved rotor and round-nosed gates were something of a departure from Rumsey’s drawing, but seemed to offer better sealing. 
At the suggestion of Pete and a few others, though, we’ve been lately moving a little closer to Rumsey’s original drawing. The rotor on his design would be easier to make, and the out-sized cams would have a better pressure angle than the enclosed cams shown here….though Rumey’s cams, as drawn, would simply let the gates drop shut, which, as the NASA engineers would say, would not be on the side of goodness.
We’re not quite sure where we will end up, at this point. The goal is to have an engine of around 1 hp that will move a 14′ boat hull upstream on most of the navigable rivers we’d find here in the eastern US.
It will use a standard water-tube boiler: happily, as Rumsey invented that, we can use something both off-the-shelf AND appropriate.
