Hi Mark,I can’t help with the Andy Ross articles,but its good to see a fellow stirling engine builder.I’v built about a dozen of various types,none of them pressurised yet.I’ll put pictures up when I work out how to do it.My books are two of James G. Rizzo’s,I’d like to get his second hard cover book. Ian.S.C

Clive 1958,how do you propose to keep oil out of the displacer?If your running the diplacer and power piston in the same cylinder ie beta type there should only be perhaps 1mm between the piston and the displacer.Even a gama or V engine doesn’t have much dead space in the tube from the displacer to the power cylinder,you’d be better looking at regeneration,and pressurisation.See James Rizzo’s “Tuba”or”Prova II”,I think there are others in his 2nd hard covered book(I’v only got the 1st one and the paper back),you need to keep oil away!You can always use a diaphragm,and do without a solid piston,there was a bit about this in Model Engineer a few years back.

Clive,not sure how you’d get rid of friction,I think some of the very early engines had little wheels on the displacer!You’d have to keep the magnet away from too much heat,possibly a guide at the cold end(could be brass or ally and sealed).I’v got 2 engines of the Ringbom type similar toJ.R.Senft’s Tapper,they work ok although not over powerful,but they show that you don’t have to connect the displacer to the crankshaft.Also got a free piston engine,so you don’t even need a crankshaft!The piston on that one has a large magnet(came from the magntron of a dead microwave oven)on the bottom end this moves inside a coil and generates a small voltage-2-3volts ac,I don’t know if this sort of thing could be reversed,maybe the magnet replaced with an iron core and a current to the coil,a switch could be opperated by the piston.The piston and displacer rest on springs,these replace the action of the flywheel of a normal engine.oops the coil and iron core would have to be attached to the displacer,could work but you would need a power supply.

Edited By Ian S C on 13/07/2009 15:31:09

Clive,start with a simple V engine get it going well,my first one was a little V water cooled engine,when ok.Its now rebuilt as the smaller of my 2 versions of Tapper.Please could you tell me what the piston in your LTD motor is made of,if its carbon I don’t know if I can get it although there is an outfit in Christchurch that makes brushes for electric motors so I could try them.

Mark thanks for the info,you need something for it to drive,a little generator,water pump or anything that goes round and round.It will stop it flying apart,Next you need a tacho of some sort,ie James Rizzo’s books show a mechanical arrangment,I made one with a 125 tooth gear and a home made worm. Clive,I don’t think so.I would be interested in whether the carbon for the piston is lubricated as some brushes appear to be or not.Don’t even know what size I need yet.