Steam Intro
For the initial version, we'll be introducing both steam and
diesel powerplants. Expanding to sail is a possibility in the future,
but something that we're not focusing on at this time.
Steam
The first engine we're introducing is a
simple and substantially overbuilt single cylinder double acting
engine.
- Single Cylinder, Double Acting
- Cylinder Volume = .04 m^3
- Piston Area = .125 m^2
- Piston Stroke = .32 m
- Overall Mass = ~900 kg
- Design Operating RPM = 250
- Max Operating Pressure = 1100 kPa
Running with a 25% cutoff, this engine
can economically produce in the neighborhood of 60hp(50 kW).
The engine uses a Stephenson Valve Gear, with a working reversing
lever (Johnson Bar if you prefer) and adjustable valve throw and
eccentric position. Power output is a function of these parameters,
and we're working on a way to integrate an indicator* into the tool
set.
Boilers
The first boiler we're implementing is a 60BHP firetube Scotch
Boiler design.
60BHP Scotch Firetube Boiler
- Boiler Cylinder
- length = 1.6m
- diameter = 1m
- mud well volume = .18
- steam dome area = .01m^3
- total volume = 1.44m^3
- total usable volume = .91m^3
- low water volume = .81m^3
- max capacity in gallons = approx
240 U.S. Gallons
- minimum safe capacity in gallons
= approx 213 U.S. Gallons
- weight empty = 1545 kg
- weight full = 2455 kg
- Firetubes
- 124 tubes
- length = 1.3m
- diameter = .02m
- tube surface area = 10.12 m^2
- tube volume = .05m^3
- Firebox
- length = 1.6m
- diameter = .47m
- surface area = 2.21m^2
- volume = .277m^3
- dry back area = .16m^3
- flue volume = .04m^3
- total heating volume including tube = .54m^3
- total heating surface area =
12.21m^2
The boiler is equipped with a sightglass in addition to 3 working
gauge cocks in case the sightglass gets gummed up with mud or other
sediment - highlighting the importance of regular maintenance.
*A Steam Engine Indicator is a device that attaches to a cylinder (or a port that comes from the cylinder) and plots the cylinder pressure against the piston position. What you wind up with is a graph that can tell you a lot about your valve timing, engine pressure and other things you'll need to tweak the engine. We'll talk more about this later.
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