Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

While awaiting the missing bits and bobs to make it run, I’ve cobbled up a belt drive water pump conversion for the whippet.

Best I can tell, the Westbury whippet was designed for either a rudder mounted water pickup on a boat, providing water circulation when the boat was in motion, or by way of an external water pump in stationary use.  The machinist built iterations I’ve seen drive a water pump using a very small pulley off of the small end (gear case end) of the crankshaft, rather than the much larger, (and therefore faster belt speed) flywheel drive.

While the brass impeller pump sold for use with the whippet is undeniably nice looking, it’s a whole bunch more pump than needed, moving far too much water,  and a whole bunch more price than I wanted to pay. So I went about searching for a pump designed for hot water, at low volume.  I found an electric motor driven “wobble drive” rubber piston type pump made for coffee machines, and also sold as an RC boat engine cooling pump running off an RC radio receiver battery.  Hot water rated, very low volume, just the ticket for a 10cc engine’s cooling pump, except for one thing.  It was electric.  I wanted a belt drive pump off the small end of the crankshaft, thank you very much.

So I did away with the electric motor, and from my junk box, found an otherwise useless stepper motor, and broke it apart, rescuing the shaft and bronze bushings.  A simple birch ply cradle supports the shaft and two bushes, as well as a cobbled together drive pulley that began life as a nylon bushing.  Tonight I haywired the pump and a belt and an electric motor, and yes, it’s going to pump A nice, steady trickle at idle, once driven by the whippet.  No leaks, works fine, and will be mostly hidden in an enclosure that doubles as a cooling water reservoir stand.
The hidden blessing of waiting for the parts is plenty of time to carry out the odds and ends, and not be tempted to rush to get it going.