Steam powered Tramp - RC Groups
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Jul 23, 2007, 01:11 PM
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Brooks's Avatar

Steam powered Tramp

My friend John Hartley is building a 4' x 8" x 2"draft, 1:48 scale tramp steamer. The prototype is the Winifred, a 1897 tramp built by Bath Iron Works, Maine. The hull is made of a 2x8 fir base with 4" of blue foam on top (wire cut to a beautiful hull shape). The whole is fiberglassed.

The tramp model uses the engine and boiler from the Midwest Heritage set. John made a ceramic burner using David Wegmuller's design and is using Andre's miniature Bernzomatic propane setup for fire. Because the propane lasts longer than the water (unlike the original Heritage Sterno setup), John wanted to be able to close the gas to protect the boiler. He uses Du-bro's Super Smoker valve, a red plastic valve that pinches the rubber fuel line shut. Spektrum's small servo is strong enough to pinch the single line shut with the Du-bro valve. The fuel hose popped off the barb fitting when the red valve closed, so the hose is now secured to the barb with a ziptie.

We are having trouble keeping the fire from flaring and burning hoses, so the design is not yet ready for primetime. When we get it debugged, I'll post photos of the setup. The prop is the 2 bladed vac u tug standard prop. The steam system moves the tramp at a scale-like speed for 15 minutes before you have to refill the boiler. We've made 3 cruises at the pond, the ship looks very nice underway.

The tramp was originally planned to be dead, just an object for ship-handling practice with our vac u tugs. John got ambitious and added steam power :-). I don't have a movie of it underway yet, just these photos of the tug practicing ship handling. The boats are made to the same scale, and work well together. The mass of the tramp makes the tug work realistic in feel and timing, I think.

Ceramic burner:
Propane setup:
Du-bro valve:
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Jul 23, 2007, 01:17 PM
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willhaney's Avatar
Very cool, would be great to see in person.
Jul 23, 2007, 02:33 PM
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tim slocum's Avatar
Brooks, how did your friend attach the foam to the 2x8 ?? Im looking for a waterproof, foam compatible glue.
Jul 23, 2007, 02:58 PM
Port of Louisville
Thats from one end of the spectrum to the other....first dead steam power!!! impressive! Can't wait to see it progress!
Jul 23, 2007, 04:33 PM
Registered User
Originally Posted by tim slocum
Brooks, how did your friend attach the foam to the 2x8 ?? Im looking for a waterproof, foam compatible glue.
I used Gorilla glue to attach blue foam to fir base.
Jul 23, 2007, 08:33 PM
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Brooks's Avatar
video of tug manuvering the unpowered tramp:
Jul 27, 2007, 05:37 PM
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Brooks's Avatar
John (machdog) has added a nice smokestack and a few other details to the tramp. We had 4 good cruises this morning, rangeing from 15 to 19 minutes. All cruises were successfully completed w/o gas flareups or any other problems :-). Now that the steam system is working fine, I'll post some photos of the details of John's setup...I forgot my camera today. Besides voyages offshore, we had fun weaving in and out of anchored barges, using the tug for assistance if the tramp could not make a sharp enough turn. Tons of fun for both skippers. Between steamups, it's also fun to push the tramp around with the tug, practicing ship-handling while the boiler room cools. If you want to have more fun with your tug, a tramp, powered or not, adds a lot of interest.

Movie with sound, 7.5meg zipped .mov format:
Jul 27, 2007, 09:56 PM
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Brooks's Avatar

Mechanical details

Driveline: Made from brass tubing and brazing rod following design of Umi's and others: 3/32 shaft, 1/8 bearing, 5/32 spacer, 3/16 stuffing box, packed grease in box too stiff for the steam engine, so washed out grease with lighter fluid. "universal joint" between shaft and engine is blue silicon tubing. Prop is a Vac U Tug standard size, brass drive dog custom made with both dog and prop filed to get a good fit, airplane wheel collar and bit of blue tube to hold prop to the dog.

Boiler room: Glassed and covered with 3M metal tape. Boiler held over burner by boiler jacket friction fit over Cu pipe cap, jacket stubbing against a big spring wound around the Cu.

Propane valve: valve cut from the Bernzomatic torch with excess potmetal hacksawed away. Fuel line is the rubber tubing that came with the Du-Bro Super Smoker kit.

Ceramic burner: 2 1/8"ID, 2 1/4"OD Cu pipe cap; leftover propane torch parts (not the Bernzomatic) for nozzle and air entrainment tube, held to Cu by the screwed-on torch's burner tip (which was radiused to fit the inner wall of the Cu); burner disk cut from softbrick, about 3/4" thick; ceramic rests on propane torch burner tip and is sealed along the circumference to Cu with high temp RTV (DAP brand).

Sheetmetal and ceramic insulation: The lining for the boiler room is attached to the superstructure and is made from Al flashing with one layer of McMaster-Carr Extreme Temperature Ceramic sheet insulation.

Smokestack: Dual smokestack, brass inner stack from Midwest's Heritage kit and 2" Al tubing for outer stack. Outer stack epoxyed to the Al flashing and the wood of the superstructure. The outer stack does not extend all the way down to the boiler, has a gap allowing heated air from the boiler room to escape. Exhaust at top of Al stack is relatively cool, perhaps due to entrainment of boiler room air from the dual stack setup.

Du-Bro shutoff: Run by Spektrum small servo that came with the radio. Hose is ziptied to a custom made barbed brass outlet fitting on the propane regulator (ditto fitting on the air entrainment tube) . Shutoff is used to snuff the fire, but the regulator valve is used for longterm shutoff.

Rudder servo mount: Metal geared servo directly attached to the rudder shaft. Friction fit hatch covering servo and Rx compartment has silicon caulk around edges for splash, but is not waterproof.

Future plans : Install displacement oiler & oil/steam separator, run de-oiled exhaust out the stack.

4 runs today without propane flare-up. This might be due to gaining experience in setting the fire, or due to low regulator setting (not much gas is needed to run a ceramic burner, one of the features of ceramic burners), or due to the propane can being empty enough so that liquid is not pulled through the regulator. I'd recommend tilting the can to put the outlet as high as the hull will allow if you build your own steamer using the tramp's design.
Last edited by Brooks; Jul 27, 2007 at 10:05 PM.
Jul 28, 2007, 03:28 AM
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tim slocum's Avatar
Brooks and Capt.Bob, when can we expect to see some paint? Have you decided on colors? Could I suggest black hull,white superstructure, buff stacks and masts.. thats my fav color combo.Just throwing ideas out there.
Jul 30, 2007, 11:16 PM
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Brooks's Avatar

Improved Boiler Design

John added a displacement oiler and an oil/steam separator. The performance of the steamer plummeted. The oiler acts like a radiator, and the loss of energy from the steam was not conpensated for by the addition of cylinder oil. The engine was now operating with less friction due to the oil, but the steam pressure reaching the engine was insufficient to turn it at the previously achieved RPM. The tramp barely moved. Turning up the fire just sent flames out the air holes in the brass wrapper, not doing any good, and potentially doing harm.

So, we installed a different boiler arrangement. The tramp still uses the Midwest Heritage boiler, what's different is how the heat flows from the burner to the stack. The flames and heat are now allowed to flow up the sides of the boiler (in addition to the Midwest-designed flow of heat past the boiler bottom and up the center flue). This makes the boiler become a "pot boiler". The heatable surface area of the boiler increases by about 5x over the Midwest design, and the steam generation capability goes up accordingly. With the same fuel setting as before, the tramp now moves like an ocean liner. At one point we were trying to figure out what the hiss was the safety valve starting to lift :-).

To regain the tramp scale speed, John kept turning the fire down and down. Eventually he found that a fuel regulator setting of only 1/8 turn gave sufficient fire to generate steam to yield a tramp scale speed. It's nice to have a reserve power capacity now; if you need more speed, just turn up the fire. With the liner speed, turns up-wind in a breeze were no problem at all. I don't have an anenometer, so can't say what the wind speed was, but it generated a nice set of waves, making the tug bob like a cork :-). As an added benefit, the pot boiler style setup is much easier to light.

I don't have photos of the tramp's new boiler, but the design is virtually identical to one I have used for a live steam loco. The key design elements are:
a) Replace the Midwest brass boiler wrapper tube with one made of hardware cloth. Discard the boiler insulation. Make the diameter of the hardware cloth tube big enough to fit over your burner, cutting away cloth as needed to clear the propane inlet tube. For the ceramic burner, this made a wrapper about 1/4" larger in diameter than the boiler. The boiler is supported by a pair of stainless steel wire stays (0.032" ss wire) poked through holes in the cloth. I just let the boiler rattle around in the tube, but you could pass stays over the top to stabilize it if you wished.
b) Surround the boiler with an Al flashing wrapper whose diameter is about 1/2"to 1" bigger than the diameter of the boiler + hardware cloth tube. Cut airholes in the bottom of the wrapper; I used a 35mm film container as a half-moon pattern, and cut 4 airholes.

The flame and hot gasses are allowed to flow up the outside of the boiler between the hardware cloth and the Al wrapper. Small Al shields are used to protect the steam hose and the safety valve O-rings from direct contact with the flame & gasses. John had already lined the interior of the superstructure with Al flashing, so the gasses simply flow up and out the 2" diameter stack. The brass Midwest stack is still retained.

With the fire turned down to run at a tramp scale speed, runtime is the same as before, about 15 minutes. With the fire turned up to liner speeds, the run time decreases to about 7-10 minutes. Water usage varied from about 3 ml/min to 6+ ml/min, depending on the setting of the fire.

Thread with more details on my boiler design (as used in my Lego Loco, which was invented by David Wegmuller):
Last edited by Brooks; Jul 30, 2007 at 11:33 PM.
Jul 30, 2007, 11:26 PM
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Tim, John is starting to paint the tramp. I passed along your color suggestions, thanks :-)

I forgot to add: When the hardware cloth is fired the first few times, it burns off some of the galvanizing. So, be sure to do your intial test runs with plenty of fresh air for yourself.
Last edited by Brooks; Jul 30, 2007 at 11:47 PM.
Aug 03, 2007, 11:34 AM
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John's starting to add details to the ship. The paint and railings completely change the appearance, moving the boat from toy to ship model; It'll be worthy of the mantle by the time he's done, I bet. He's going to follow, I believe, Tim's suggestions for colors. The appearance of the tramp changed once it was picked up by Gulf Oil, so the exact paint scheme, particularly the stack, is still under consideration.
Aug 03, 2007, 12:16 PM
Capt.Crash's Avatar

Very Cool!

I can't wait to see it finished and in action!

Capt. Slick
Aug 05, 2007, 04:10 PM
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Brooks's Avatar

Great day at the Pond

Great day steaming the tramp Winifred. Good runs, 3 @ 20 min each with 8-10 minutes of water left in the boiler after a run as a reserve/boiler protection. The cylinder oil makes an efficiency difference, now that we have the boiler pressure under control, allowing nice speed with only 3ml/min water usage; also, the oscillating engine now sounds more like a sewing machine, rather than a clatterbox. At the scale-like speed, turns require seamanship - will the turn upwind, with it's slower turn rate & larger radius allow me to miss the shore?, etc. It's nice to have a zippy, manuverable tug, but it's also fun to have a slower turning vessel too :-)

Today we discovered that the discharge port of the oil/steam separator needed to be clamped shut, otherwise the steam and oil tended to exit into the hold. The steam escape pipe rises maybe a foot above the separator, and perhaps if the pipe gets a slug of water (from say, priming on startup), it forces the steam to exit from the discharge port. Once the clamp was in place, the steam escape pipe sent up a beautiful jet of steam as the tramp cruised. The plume adds much to the realistic appearance of the tramp, that element of randomness that moves the picture from toy to reality. On a sea cruise, when the vessel is far offshore, the appearance is so lifelike it's uncanny. The builders of that era built beautiful lines into everyday work craft.

The ceramic burner is very quiet, especially if you are used to Accucraft loco poker burners :-). The ceramic burner's heat is apparently mostly absorbed by the boiler as the superstructure over the boiler room does not become very hot. You can hold your hand above the tramp's stack without fear of burns.

John took several photos and movies, too. We'll post them when he gets back from his trip.
Aug 05, 2007, 04:42 PM
Registered User
That really is a handsome ship!

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