Bryan Finch

This freelance steam turbine launch by Bryan Finch was inspired by an article in Model Boats magazine back in December 2001. The turbine has a single stage rotor enclosed in a housing with the steam jet acting tangentially to the blades. A 6:1 reduction gear is between the turbine wheel and output shaft.

The turbine wheel is 50mm dia and comprises 60 shallow V-shaped blades. The steam jet is 0.025” dia  for a length of 1.6mm and expands along a 10 degree included single cone which tapers off to match the diameter of the turbine wheel.

The exhaust pipe from the turbine wheel enclosure is 7mm internal diameter. Steam is supplied from the gas-fired centre-flue boiler at a pressure of 90psi without superheat.

Stainless steel ball bearings are used on both shafts in the turbine. Rotor speed off-load is probably in excess of 30,000rpm. A Mk 1 version of the turbine with plain bearings and a less tidy casing was displayed next to the model.