Reliable Steam Engine Co

[KennyT]

Looking to start a new engine build. Has anyone purchased plans form Reliable Steam Engine Co.? Are the good quality plans? Was wondering of the pdf plans are worth the price.
Thanks

KennyT

[barts]

Note that these plans detail the machining of the castings they also sell (aside from the turbine, which is a steam hog as all small turbines are...) . As a means of determining whether or not you want to tackle such a project, the plans offer an good way of "putting one's toes into the water". There are several boats with these engines running around the US; the company has been around since the 1960s.

I've not looked at the plans or machined their castings.

What size engine are you considering building?

- Bart

[KennyT]

Bart,
Thanks for the reply. Looking to build something in the 3 to 5 HP range. An engine I can eventually power a small launch with.

KennyT

[barts]

Neat!

As far as planning goes, I'd work backwards from your boat's displacement to pick a suitable engine design. Typical steam powering levels are 1-3 hp/ton of boat displacement, with 1 hp/ton being slow, and 3 hp/ton being at the "sporty" end of things. Where do you plan on operating your boat?

Here's a photo of our boat "Otter" nearly 20 years ago taken in the San Juan Islands in WA:

20050609_042516_43B1A277.jpg (172.3 KiB) Viewed 1212 times

- Bart

[fredrosse]

True engine horsepower for a steam engine is according to the "PLAN" formula.

HP = P L A N /33,000

P = Cylinder mean effective pressure, the differential pressure acting on the piston, Pounds per Square Inch differential, (PSID)
This number can be approaching maximum boiler pressure, giving maximum horsepower potential of the engine, however running the engine with such a high mean effective pressure would be very un-economical. Efficient steam engines generally have their valve gear set to "cutoff" steam admission at around half piston stroke, and the mean effective pressure is around half the main steam pressure.

L = Length of piston stroke, expressed in feet (FT)

A = Area of piston upon which the steam pressure acts, Square Inches, (in2) , equal to the cylinder bore squared x Pi / 4 Area = (3.14 / 4 ) x Bore x Bore

N = Number of power strokes per minute. For a single cylinder, single acting engine, this is the engine revolutions per minute (RPM). A typical double acting single cylinder engine this number is twice the RPM, and for a simple two cylinder double acting engine it is 4 x RPM, etc.

Taking a typical example of a single cylinder double acting engine, 2-1/2 inch bore, 3 inch stroke, running at 350 RPM with 120 PSI main steam pressure:
P = Half the main steam pressure = 60 PSID
L = Stroke, in feet = 3 x 1 Ft / 12 inches = 0.25 Ft
A = Area = (Pi/4) x Bore Squared = 4.91 square inches
N = Power Strokes per Minute = 350 x 2 = 700

33,000 is the number of Ft-Pounds of energy required per minute to be equivalent to "one horsepower", a number defined by our great steam hero, James Watt.

PLAN/33,000 = 1.56 Horsepower, a typical power for a 1 ton displacement hull at "Hull speed". Hull speed in Knots is equal to about 1.3 x (squareroot of hull waterline length, in Feet). This translates to a typical steam launch hull with a waterline length of 16 feet, making around 5.2 knots of speed (6 Miles per Hour) You can input your own values here to examine your options. The FAQ Section of this website provides more detail if you like.

[Lopez Mike]

To avoid "furiousness" in routine operation, I would power such a boat around 50% higher. Or more! One of the pleasant aspects of a steam launch is the sense of not working that hard. No thrashing about whenever you espy another steam boat. Most unseemly. Fred's boat is a great example of stately progress though the water.

I have a 3 x 4 single and it moved my previous hull (around a ton) easily at it's hull speed.

Mike