Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Steam => Topic started by: tonyH on January 11, 2010, 12:18:40 pm
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There's a battered single cylinder slide valve unit on e-bay at the moment and it looks to be about 3/4" bore with a longer stroke.
Is it likely, given a suitable boiler, that it could power a flat bottomed paddle boat of 40" x 8" with a 2" draft?
If yes, can anyone recommend a suitable type of boiler with a maximum length of about 9" and 6" diameter?
There is one more 'nasty' in that the boiler and engine would be at opposite ends of the vessel and this would mean about a 20" run of steam pipe.
Any help would be appreciated.
Thanks
Tony
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before you go any further 20" will be a problem but the main thing is did you know that it will not self start, you will be able to alter the speed but not stop it or change direction while on the water.
peter
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Tony,
there are several 'battered' steam engines being offered by the same seller and it is anybody's guess what they will end up selling for, as anything 'steam' seems to be fetching good prices at present.
As to the engine, I would have though it would power a 40" boat quite easily, although the inverted oscillator twin offered at present could be a better bet for a paddler. A 20" run of pipe is a fair old stretch, but if it's superheated and insulated I would guess it would work, once all the pipe work is thoroughly warmed up, although you are going to get some condensation forming in the pipe. It might be worth considering having a drain valve part way along the pipe run.
As for boilers, I'll leave that to others, as I just buy mine and plumb them in.
Good luck if you decide to bid.
Neil
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My honest advice- don't do it mate.
Greg
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It's only really a 'fag packet' idea at the moment but I've got a Hemmens setup sitting doing nothing and I came upon the drawings below, then, while idly looking at e-b, I came upon the item you've seen Neil and that set the cogs away...You know, nice long stroke etc.
Someone has also given me a load of 1mm ali sheet so a lot of the fabrication would be simple etc.etc.
I wasn't even worried too much about reversing Peter but a 545 motor with a dog-clutch could take care of the starting.
No Greg, I wouldn't do it if it started to get silly on the money front anyway. I haven't checked the price today but it would only be treated in the same way as the Pools because, as I said, I can always use the Richmond/Wharfedale kit.
Hence the question about whether, all other things being fairly equal, that size of motor would actually have enough grunt.
The boat looks interesting anyway.
Thanks
Tony
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Patience is a virtue....
As previously stated there is a bunch of junk going out on E-bay with silly prices under the heading of "steam". Scan E-bay.de & E-bay .com & you can spot the occasional jewel. Self starting will need twin cylinders with 90 degree throw/crank or a secondary mechanism to kick her over. Unless of course you use one of these which allows neutral forward & reverse.. http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=400094153099&ssPageName=STRK:MEWAX:IT (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=400094153099&ssPageName=STRK:MEWAX:IT) The "best" engines I have spotted are on e-bay.de...Sorry guys but that's the truth to date....
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I have an 80" sidewheeler paddler powered by a 3/4 x 5/8 single and it has heaps of power to push this large hull. I throttle it but not so slow that it stops and I have never had a stoppage in several years of running it. I have no reverse but it does not cause many problems. It does have a waterpump and a 9" x 6" boiler so can do long runs if needed. I have played around with a reversing gearbox but took it out again. I have seen a single cylinder motor set up with an electric motor as a starter for emergencies and that might be worth considering. All I can say is go for it and have fun playing around, you can always swap motors later. Mine is chain drive and the motor is on an alloy plate with slotted mounting holes to adjust the chain so it is easy to put another motor in if you have a second mount plate. Cheers, Ian.
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O0....Tony....why not post & join www.paddleducks.uk.com] ...Derek
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I think 9" is a little to long if of the centre flue type, as you would never get the heat to the end, Ian what type of boiler type are you using.
As for the engine on ebay, hummmm, you might end up doing so much work on it, it might be easier to start from scratch. ;)
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Thanks all,
1. Thanks Benj, I've had a look on .de and I see what you mean. There are a couple that would bear thinking about at the moment. As far as self starting is concerned, I've a 'cunning plan'..........
2. Thanks too Ian, it would be very much of a budget (if you can ever use that term with steam) playaround. My Wharfedale boiler will fit anyway but I'd just wondered whether it would produce enough volume of steam to suit.
3. Derek, If I get going on it, I promise to look to paddleducks!!!!
4. Phil, you're probably right, but if I can get something for under, say, £20.00 it would be worth the extra money for the plus gas etc......
Regards to all
Tony
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Phil, my boiler is to the original Rayman design that came out with the engine plans. I know he now says that was too big but I have no problems however I fire it with a Primus "roarer" type burner from a plumbers gas set and use two 225gm gas cylinders in tandem. It will hold 80psi if I want it to although that does ice up the cylinders after a while and it only needs 40psi to drive the boat at better than scale speed. I can get the paddlewheels to kick up a wake that comes up over the stern deck if I give it full noise on 80psi! The Rayman engine, pump and boiler have worked well everytime I take her out. I have also used her as a test bed for about 4 or 5 other engines, it is easy to swap them with the chain drive as crankshaft height does not matter. Cheers, Ian.
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There are a couple that would bear thinking about at the moment. As far as self starting is concerned, I've a 'cunning plan'
Regards to all
Tony
Meccano ratchet wheel attached to the shaft with an servo/actuator momentarily engaging/pushing a flipper pawl. Bump the servo until you have motion... Simples... :-))
http://meccanoman.co.uk/catalog/index.php?cPath=1_55 (http://meccanoman.co.uk/catalog/index.php?cPath=1_55)