Compound uniflow steam engine

[Jim Holmgren]

Hi I had this idea about a triple compound uniflow radial engine.

I post a picture of the basic idea of it.

The red cylinder is the high pressure single action cylinder with a inlet valve (poppet, rotary or piston).

The uniflow ports will open at 120° and go to the mid pressure cylinder with no valve, and in turn open its uniflows ports at 120° that will go to the low pressure cylinder...

Will this have any practical utility? It seems easy to make as it only have one valve and one crank, but it may not have any advantage over a single cylinder with a short cut-off?
It will maybe not even work as I think it would?

 

[Charles Lamont]

Its a nice idea, but I think you will have problems with too much compression in the hp & ip cylinders. A uniflow normally needs to breathe freely to exhaust.

 

[Anatol]

I like your design thinking, its very much like my own. I've drawn a few uniflow triradials. I love Westbury's Cygnet Royal, and Verberg had a nice one with a disc valve. I also think simplifying valve systems is a useful idea. I love the idea of rotary valves but they don't seem to be very sucessful. As Tom Kimmel famously said: "The great axiom of steam engine design is that there are two kinds of valves: poppet valves and those
that leak." I'd love to know of designs that work. I've designed a few myself but haven't built yet. However, there is a reason (at least one) that compound engines were phased out and that uniflow were never - I think - compound.
Very different kinds of engines. Compound were high torque, efficient and slow, good for boats etc. Uniflow tend to be high rpm, developed in the context of electrical generators. As Charles said, uniflow engines depend on having low temp/low pressure outside the exhaust Ports to evacuate the cylinder fast. This makes it difficult to apply to an already hot mp cylinder.
I'd be interested to know if your idea has progressed and also if others have insights.