Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Steam => Topic started by: pipercub1772 on November 04, 2010, 01:56:18 pm
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hi, i have been refurbishing a launch for a few months stripped it down and added some dummy ribs repainted the hull and re varnished, some new brass fittings new condenser fitted my old cheddar boiler, the one previously installed did not have a site glass so no indication of how much water was being used. fortunately it had a hardly used hemmens max 2 piston valve engine i have run it on test a couple of times and it runs great its got a throttle valve and a reversing lever which i have connected to 2 servos i have never had a piston valve before but noticed you can get good throttle response by just using the reversing valve. what are the pros and cons of using as i have set it up ie using throttle valve and reversing valve or just using the reversing valve for controlling reversing and throttle and just leave the throttle valve permanently open . regards allan
(http://s4.postimage.org/K6fQS.jpg) (http://postimage.org/image/2llt8g5us/)
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To me the whole idea of steam is a much more relaxed way of model boating and so I enjoy manoeuvring my model gently and slowly. Leaving the throttle on full and using the reversing servo to control gives you an on or off approach, which is not attractive to look at and is very wasteful on steam. Not only are you using full revs when a much smaller amount would do the job but the reversing valve has a definate position when the port is fully open and it should only be in that position.
I may be wrong, and I'm open to alternative suggestions, but I think the reversing valve shoukld be used for reversing and the throttle should be used for speed control.
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hi.......... i have a Max2,,,, and it run a work great......i use bot valve if i was sailing with full speed i will look stranges,,. bot Like Bunkerbarge sai......... reversing valve for controlling reversing, and the throttle should be used for speed control only...
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thanks for that i will stay with youre sugestions. regards allan
(http://s2.postimage.org/G1puS.jpg) (http://postimage.org/image/2dbsi7pyc/)
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Good afternoon! :-)
Very nice launch Pipercub = neat and new! :-))
I also agree with both above. A 1/4 turn valve will deliver the exact amount of steam you need to sail nicely..... if you have Stephenson reversing gear.
But looking at you engine, I wonder if the "in&out" side engine control valve there is, does not do the same job. So I am not so sure now that you need a second control valve embarrassed:.
Stephenson reverse gear is not acurate to control the steam flow.
Cheers! ;)
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hi..... the launch look good,,,,,,,, i run my Max2 on 60-70 psi.....if you run it with to low psi,,,it will work as a waterpump,,,so go over 50,psi,,,,
here is it..on the lake
http://www.youtube.com/watch?v=2SkNPyEKK6A
Rregards Bernhard
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thanks for the reply not sure what you mean regarding it will act as a water pump regards allan
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hi..... it neat some psi a,list 50 psi to work good,,,
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thanks bernhard, i am not using the water pump on the engine so dose it still matter what psi i run at .regards allan
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Hi........ if you run this engine on to low psi...the water just run true it.?..it work a lot better on 50 PSI AND UP...........
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Hi Allan,
I think what Bernhard is trying to say is that if you run the engine on low steam pressures it suffers from bad cylinder condensate problems and will lead to unreliable steaming.
Greg
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Hi..Thanks Greg........yes that ,what there will happens....When i got mine, John Hemmens told me to run it like that,,,............ ...............Regards Bernhard
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thanks guys, i have got it now i will run on 60/70 psi kind regards allan
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thanks for the reply not sure what you mean regarding it will act as a water pump regards allan
[/Stquote] :-)
Steam at about 25 psi is considered wet. To realise the potential of the Max 11 you need to run the engine between 65 to 80 psi and make sure there is oil in the engine. There are two very small holes in the cylinder head above each cylinder and you should see a witness of oil from the holes which will indicate the engine is getting suficient oil. If the engine is slow check the oil supply and do make sure that it is steam oil and not the thick stuff some engines need. :-)) john hemmens.
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Thanks for that information John. I am using 460 steam oil in the lubricator and a normal synthetic engine oil in the 2 oil cups, i will take note of the wetness from the cylinder head as you described. May i compliment you on a fine looking and extremely well engineered engine. I intended to get one many years ago when i visited you're business at Thorganby, unfortunately funds did not permit that then. but its a fine engine i have had it running about 10 times on test and in the launch and it operates superbly. i am getting 25 minutes running time without the water pump, i am also using a 60 mll 3 blade prop. Kind regards. Allan.