Paddleducks
Other Marine Models => Live steam => Topic started by: malcolmbeak on October 12, 2007, 03:34:34 AM
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Hi PMs
On the off chance that someone might be interested, here is some information on a model paddler being built in the South of France.
One time member of the St.Albans society, Jim Brassett now lives in the south of France. He is the one responsible for my interest in model steam boats. About a year ago, he happened to see the David Niven version of "Around the World in 80 Days". Towards the end, Fillius Fogg crosses the Atlantic in a real caricature of paddle boat – the "Henrietta". Very obviously not a real paddler as you can see the wash from a propeller, the paddles are being dragged round by the forward motion and the funnel is practically over the centre of the paddle shaft. Anyway, it took his fancy, the DVD was purchased and a number of stills taken from it.
Last October (2006) when we were visiting him, a design for the hull was drawn up, and a start made on a plug for the hull mould. By the time we visited again in May, the hull was made together with paddles and boxes and the start of the deck and superstructure. An old boiler (one of many he has) was fitted along with a singles cylinder single acting oscillator. Drive was by a long rubber band to the seven inch diameter paddles. Trials proceeded with odd bits of steel and brass to bring her down to the waterline, the meths burner fired up and steam raised. Performance, it has to be said, was fairly gentle.
As the engine was obviously not up to the job, we discussed what was needed, and I returned home promising to see what I could come up with. My initial thought was to design and build a new engine, but in the meantime I thought I would carry out some tests on one I already had. A crude paddle was made up, seven inches diameter, with eight floats three inches long and three quarters of an inch deep. This was slightly over the total width of those on Henrietta. The paddle was first fitted directly onto the crankshaft of one of my little ⅜ X ⅜ twins – the same as the one in Cyril. On about 20 lb of air, it turned over gently when held in a washing up bowl of water deep enough to cover the bottom float by about a quarter of an inch. Not quite up to the job, but how would it perform if it was geared down. So two pulleys were made – a three step to go on the crankshaft, and a larger two step for the paddle shaft. A long belt was made from a piece of 2.5mm O ring cord, and everything assembled on a strip of wood. A number two test tank was made from odd strips of timber and the hardboard bases of some old drawers. The engine and paddle assembly was clamped to the side of the tank, water added to just cover the floats by about a quarter of an inch. The drive belt was set up for about a three to one reduction, and the air turned on. My word! All my worries about not being enough power were gone. On twenty pounds the paddle wheel flew round – I'm not quite sure how fast it was going, but I would guess about 200rpm. Switching over to steam power produced a similar performance. I'm absolutely amazed at just how much power that little engine seems to produce.
I made a video of the trial (rather naff commentary I'm afraid) Follow the link to see it' http://www.paddleducks.co.uk/forum/dlman.php?func=file_info&file_id=767
Jim now has the engine , pulleys etc. Hopefully he will give an up date before too long
At the moment, the plans for the engine are in the Downloads under "Steam Engine Articles", but I think Eddy is going to move them to the "steam Engine Plans" section.
[Edited by Admin] Malcolms plans can now be found at: http://www.paddleducks.co.uk/forum/dlman.php?func=select_folder&folder_id=233
Malcolm