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Old Mar 24, 2012, 01:05 PM
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Help!
Dead space on a steamboat engine

I'm building a 1/32nd scale, 62-inch long scale model of the W.T. Preston. We are starting the build of the scale steam plant. It will be direct drive from piston, crosshead, pitman arm to paddlewheel. The engine will have 5/8" bore cylinders and 2.28" strokes. My question is how much dead space should we allow for water condensation that will form? The boiler will be able to produce quite a bit more steam than the engine requires. I've heard of spring loaded drain valves actuated by pressure that we could attach to the ends of each cylinder. Anybody have suggestions on how to combat hydrolock using relief valves? I'll be running the engine at 40psi to keep the steam temperature high to reduce condensation. All piping and the engines themselves will be insulated. I have enough room to open these 4 valves via a servo if that would work on startup. Getting at these valves is impossible once the superstructure is in place, a 5~9 minute job to lift off superstructure.

Mike
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Old Mar 25, 2012, 04:15 AM
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Quote:
Originally Posted by hookpilot View Post
I'm building a 1/32nd scale, 62-inch long scale model of the W.T. Preston. We are starting the build of the scale steam plant. It will be direct drive from piston, crosshead, pitman arm to paddlewheel. The engine will have 5/8" bore cylinders and 2.28" strokes. My question is how much dead space should we allow for water condensation that will form? The boiler will be able to produce quite a bit more steam than the engine requires. I've heard of spring loaded drain valves actuated by pressure that we could attach to the ends of each cylinder. Anybody have suggestions on how to combat hydrolock using relief valves? I'll be running the engine at 40psi to keep the steam temperature high to reduce condensation. All piping and the engines themselves will be insulated. I have enough room to open these 4 valves via a servo if that would work on startup. Getting at these valves is impossible once the superstructure is in place, a 5~9 minute job to lift off superstructure.

Mike
Mike,
You should leave 1/32" between the piston head /top and bottom/ if you make the cylinder 1/8" longer O/All this allows a 1/16" space at both ends and you can then make the register on the covers 1/32" to fit into the cylinder leaving a 1/32" space.
I wouldn't worry too much about condensate and hydraulic locking, you can clear this by turning over the prop, in your case the paddle wheel which will clear the condensate after about 6-8 turns and pump it over board into a can and the engine will fire away.
Another method is if you have a radio operated reverse if you juggle the controls back and forward it clears the condensate.
I have been running D10's for many years and I used to fit drain valves but no longer , I have never had a problem of stopping in the middle of the pond and on re start having a hydraulic lock, it just doesn't happen.

If I may comment on your statement that it will take 5-9 mins to lift the super structure to get into the boiler I would make sure that I could get into it very quickly, things can happen that requires instant access, for instance , a mate of mine ran his boiler dry, no damage to the boiler, on a very detailed Drifter which set the timber lagging on fire and it was only due to a younger member who jumped into the water and sank the boat to put out the fire that he didn't lose the super structure and the boat.
Remember we are working with fire and many things can happen so I would redesign the top to be removable, hope this helps.

George.
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Old Mar 25, 2012, 10:03 PM
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RE: Rapid access to boiler

George:
Thanks for the very helpful information on dead space. You comments on rapid access to the boiler are well taken. I'm doing a lot of head-scratching to see how I can quickly detach the 6 turnbuckles that brace the crane that must be unhooked from the deck before I can lift the superstructure off. A CO2 fire extinguishing system is in the works. I'm thinking of using an old CO2 inflated life vest cartridge and pull handle, activated by a servo to discharge the 20g bottle. It would be hooked to a heat/fire detector in the engine space. 20g of CO2 will more than replace all the air in that space. I'll be doing much testing of this idea before installation.

Mike in Edmonds
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Old Mar 26, 2012, 11:25 AM
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Hi Mike,
You may want to look into the quick release turnbuckles attachments that the larger pond yachts use.
http://mysite.verizon.net/vzeee83u/m...s222/id14.html

and item #260 at next link reminds me of full size boarding gate "quick release" turnbuckle used on sailboat lifelines
http://www.midwestmodelyachting.com/...dh/cKDH07.html
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Old Mar 26, 2012, 12:04 PM
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Sounds beautifully and accurately detailed. I use elastic rigging lines for mast and stack etc and then use simple wire hooks through eyelets. Various hardware options abound- - they are much more forging when accidentally snagged by something in transit etc also!!

They are always taught and are easy to remove and install! I find a great selection of size at sewing stores- they do mostly come in black if that is a problem...not for me- easier to see
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Old Mar 26, 2012, 04:44 PM
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Quick release rigging

Quote:
Originally Posted by mogogear View Post
Sounds beautifully and accurately detailed. I use elastic rigging lines for mast and stack etc and then use simple wire hooks through eyelets. Various hardware options abound- - they are much more forging when accidentally snagged by something in transit etc also!!

They are always taught and are easy to remove and install! I find a great selection of size at sewing stores- they do mostly come in black if that is a problem...not for me- easier to see
Mogogear: Great ideas. I've already ordered 6 turnbuckles from the Florida vendor noted above. My rigging is for more than looks, however. It actually is part of the backstays to brace the A-frame and are needed to be under tension when rigged. I may yet opt for electric power if I can't find a way to quickly get inside the boat. Forward hog rods brace the front of the A-frame and those two rods penetrate the cabin deck floor. How am I going to allow for this? I've considered cutting small slits between the hog rod decking holes out past the edge to allow removal of the superstructure. In this case, all I need to disconnect will be the 4 main turnbuckles. In the final calculus, all my effort and time building this thing and protecting the investment will outweigh the uniqueness and desire of installing a steam plant, and save me a lot of money to boot. My mind changes like the tide. Stay tuned for the next set and drift.

Mike in Edmonds by Puget Sound
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Old Mar 26, 2012, 04:52 PM
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Quote:
Originally Posted by Reg Hinnant View Post
Hi Mike,
You may want to look into the quick release turnbuckles attachments that the larger pond yachts use.
http://mysite.verizon.net/vzeee83u/m...s222/id14.html

and item #260 at next link reminds me of full size boarding gate "quick release" turnbuckle used on sailboat lifelines
http://www.midwestmodelyachting.com/...dh/cKDH07.html
Hi:
I should be getting 6 of these beautiful turnbuckles in a few days from Roger at Model Yacht Fittings in Florida. I chose these because they are near identical in form and proper scale for Preston's big hog rod turnbuckles. Maybe with a hook type end fitting I could get the superstructure off in under 30 seconds. We'll see.

Mike
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Old Mar 26, 2012, 04:56 PM
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Follow-Up on Regatta Formats

I'd be very interested in hearing how my model would be entered at your local regattas? What categories? What would it be eligible to compete in?

Mike in Edmonds
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Old Mar 26, 2012, 06:09 PM
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Quote:
Originally Posted by hookpilot View Post
I'd be very interested in hearing how my model would be entered at your local regattas? What categories? What would it be eligible to compete in?

Mike in Edmonds
Being near you , I will be up in Seattle for the NW modelers regatta in June( help at the boat pond for the Wooden Boat Club on Lake Union> http://www.shipmodelers.com/shipmode...b_Welcome.html

Check them out about judging, regatta's etc- great Group of fellows!

I think the Foss Cup is in August and is held over in Bellevue. http://www.shipmodelers.com/shipmode..._Foss_Cup.html


I want to enter some towing competitions at the Foss- but I will have to see how my side paddle tug fares under load . It can cause some potentially capsizing issues on some side wheel paddlers.

I watch for your news eagerly as I also have a stern-wheeler under construction. Not near so scale nor so big. It is a replica of a historic boat from the Arrow Lakes region of the upper Columbia River- Cheddar steam powered....
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Old Mar 26, 2012, 06:26 PM
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Mogogear follow-up

Quote:
Originally Posted by mogogear View Post
Being near you , I will be up in Seattle for the NW modelers regatta in June( help at the boat pond for the Wooden Boat Club on Lake Union> http://www.shipmodelers.com/shipmode...b_Welcome.html

Check them out about judging, regatta's etc- great Group of fellows!

I think the Foss Cup is in August and is held over in Bellevue. http://www.shipmodelers.com/shipmode..._Foss_Cup.html


I want to enter some towing competitions at the Foss- but I will have to see how my side paddle tug fares under load . It can cause some potentially capsizing issues on some side wheel paddlers.

I watch for your news eagerly as I also have a stern-wheeler under construction. Not near so scale nor so big. It is a replica of a historic boat from the Arrow Lakes region of the upper Columbia River- Cheddar steam powered....
Mogogear: I'm a member of the NWRCSM and their webmaster. I'm hoping we will include a competition category that might be called "on-water scale judging" but doubt it will come to pass. There's not enough participation. What could be a nice venue would be to have an exhibition time scheduled in the day to have boats that would not be entered in a navigation event, to display their ship and its capabilities.

Mike in Edmonds
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Old Mar 26, 2012, 08:12 PM
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We that is grand news!! I have fun with those of your club that come down to the Crawfish Festival..Being a live steamer I got to meet and hang with Lee Stewart and his family this last Summer..I plan on dual club memberships after my visit..

You know more about what goes on in our neck of the woods than I do- so I will sit back down
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Old Mar 27, 2012, 10:16 AM
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You guys are lucky! There is NOTHING hundereds of miles close to me. Clubs/regattas/etc


BTW You will be really happy with those turnbuckles!
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Last edited by Reg Hinnant; Mar 27, 2012 at 10:21 AM. Reason: addition
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Old Mar 27, 2012, 01:47 PM
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Mike,
Your model paddler looks superb, could you post some more pics of it in the day light.

Question,

Does the "A" frame of the derrick tilt or is it fixed by the 2- ties to the upper cabin super structure.
Could you make the derrick fixed to a small permanent bow deck with the whole rear deck behind it removable and this would only require the 2- ties to be removable with say a shackle with a pin thro' it.
I have seen a stern wheeler with the drop down ramps at the front fixed like that which allowed the complete super structure to be removed to get into the steam plant, or am I way off the mark?

If you install a steam plant how are you going to view the boiler sight glass and the pressure gauge, it would be a shame not to install a steam plant in such a beautiful model

We don't get many model stern wheelers in Scotland, suppose it's the windy weather that we get and none have been built on the Clyde but I believe that one of the Mississippi stern wheelers was built at Yarrows on the Clyde and shipped over in parts.

George.
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Old Mar 27, 2012, 06:39 PM
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Quote:
Originally Posted by ooyah View Post
Mike,
Your model paddler looks superb, could you post some more pics of it in the day light.

Question,

Does the "A" frame of the derrick tilt or is it fixed by the 2- ties to the upper cabin super structure.
Could you make the derrick fixed to a small permanent bow deck with the whole rear deck behind it removable and this would only require the 2- ties to be removable with say a shackle with a pin thro' it.
I have seen a stern wheeler with the drop down ramps at the front fixed like that which allowed the complete super structure to be removed to get into the steam plant, or am I way off the mark?

If you install a steam plant how are you going to view the boiler sight glass and the pressure gauge, it would be a shame not to install a steam plant in such a beautiful model

We don't get many model stern wheelers in Scotland, suppose it's the windy weather that we get and none have been built on the Clyde but I believe that one of the Mississippi stern wheelers was built at Yarrows on the Clyde and shipped over in parts.

George.
Greetings George: Glad to hear from someone on your side of the planet. About the A-frame: it freely pivots on U support brackets and pins. The hog rod bracing system is needed to take the strain from the crane when loaded and keep the A-frame in a vertical position. There is a little bit of strain on my model's hog rods. I'm not lifting heavy loads, maybe a pound or so of scale logs, stumps and a 2-yard clamshell dredging bucket. So it's not just for looks. I think I've got a way figured out to quickly get at the boiler. Monitoring the boiler will have to be done via several automatic features- fuel metering via a boiler pressure sensing system that will adjust the flame intensity, and an automatic boiler feedwater pump to make sure I don't run it dry. I'm positioning the boiler pressure gauge so it can be read through a side window. The engine room will be protected by a CO2 deluge system I'm designing made from an old aircraft type mae west life vest. I'm taking the 20g CO2 cartridge holder and pull handle and attaching a 1/4 scale RC servo with enough power to discharge the mechanism when it gets the proper signal from a heat detector harness mounted on the ceiling and walls of the boiler room. When it fires, the 20g CO2 cylinder will be able to fill a space of 2000 cubic-inches, substantially more volume than the boiler room. When it senses too much heat, it shuts down the butane supply valve and fires the life-vest cartridge. Then a little RC 1/32nd scale deck hand runs around the boat yelling "FIRE, FIRE! ABANDON SHIP!" Then I go for a swim.

I'm using the Spektrum DX8 and will be using its telemetry data link to monitor a few critical functions, boiler water level and boiler room temperature. As a further added safety feature, I'll have quite a bit of boiler make-up water to pump into the boiler while in steam. Given my calculated steam consumption of 320 cubic inches per minute and needed water evaporation rate, about a cubic inch per minute, I'll always have more water on board than fuel to evaporate it. I'll always be fuel limited, not boiler water limited. In my early planning, I determined that 1/32nd scale for W.T. Preston would allow me the luxury of cramming in all kinds of steam plant features and sub-systems, all needed for such an enclosed powerplant. The model will spend far more time in the eyes of the public, and me, sitting on a display table, opened up to show all the moving parts. Building big, however, has it's drawbacks, and they are not trivial. But, what the hey, I'm in it for the engineering challenges and satisfaction of making it all work.

Cheers,
Mike in Edmonds
P.S. I'm going down to the shop today to take some beauty shots of the boat. Will post later today.
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Old Mar 27, 2012, 08:29 PM
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If you are serious about all you described above, it is really not needed. If a modeler becomes acustomed to the way a steam plant or loco operates, simply timing the run is all that is needed. I have boats with enclosed steam plants and they run just fine without any complicated systems. I am an engineer for a living and I would not want all that stuff in my steam boat.
If you are going to show your boat please tell any people asking about the stuff crammed in your boat that is not all required, since the complication would scare off a few would be souls.
thanks
Steve
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