The
Two-Stroke Engine Commemorative page
I just love everything about 2-stroke engines, and own quite a number of
them. I hope to develop here a repository of just how they inspire
me. I understand the State of California does not permit 2-stroke
outboard motors any more, for their dirt. But, gosh, they're so neat!
2-stroke engines I currently have in service:
Wonderful
drawing at lawnboy.com, of simplicity
itself when it comes to mowing one's lawn.
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Lawn mower engine, Lawn Boy, 6.5 hp DuraForce, acquired 2002.
Here's a real champ of an engine, taking 32:1 fuel/oil. It's a little
smoky when it first starts up, and full-choked, it kicks out a substantial
cloud until it warms up. It is a truly light and simple lawn
mower. I understand they now only sell 4-stroke mowers in the consumer
market. My, how time marches on.
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Chainsaw engine, Husqvarna, 50 cc, acquired 2003. This powerplant
is truly something to see, with all that fine Scandinavian design.
It's teamed with an 18" bar, for most homeowner work you'll ever see.
Paul Harvey was right about these "Huskies". Fuel is 50:1 gasoline/oil.
The engine features a decompression control that makes for truly easy starts.
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Leaf Blower engine, Echo, 44 cc, acquired 2005. 40 mm bore
x 35 mm stroke. Top RPM ~8000. I wanted to get serious about
the vast number of leaves that fall through November and December of each
year, here at Xana'02.
Thus, I went to the backpack mounting, once my old 25 cc unit (as in Sears
engines below) gave out.
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Model aircraft glow engine, OS Max, 0.46 cu in (7.5 cc), acquired
2003. Bore = 22 mm; stroke = 20 mm. I've enjoyed model aviation
for many years, and my goal is to fly something like my 55" wingspan "buzz-bomb"
without assistance. The guys at NVRC told me my old OS Max .40 just
wasn't putting out the stuff for a 5-pound plane. Fuel is typically
60% methanol, 20% nitromethane, 20% castor oil and synthetic lubricant.
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Line trimmer engine, Weed-Eater brand, acquired 2000, ~22 cc.
This was the first gas-powered yard tool I had, when I lived in a townhouse
and was tired of crawling on hands and knees. Takes 40:1 fuel/oil
(picture now a garage full of different gas cans...). To get jollies
sometimes in the winter, I'll go in the garage and yank this one into action.
It has now ended its 6th year of service.
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Model truck glow engine, Traxxas, 2.5 cc (0.15 cu in; TRX 2.5 Racing
Engine), acquired 2003. Bore = 15 mm; stroke = 15 mm. This is the
newer generation TRX 2.5 Racing Engine, as was standard on my T-Maxx, and
it's something to get opened fully up. Traxxas says this boy will
turn 40 000 RPM, and I've never heard any engine scream like this one does,
once the slide carburetor gives it a whiff of full throttle. It burns
a product called "Blue Thunder", or 30% nitromethane model car fuel.
A good outing will see me consume a 500 mL bottle of the stuff. The
truck, seriously, looks to be capable of 40 mph.
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Model car glow engine, Traxxas, 2.5 cc (0.15 cu in; TRX 2.5 Racing
Engine), acquired 2005. This is part of a Traxxas Nitro 4-Tec, a
truly fast 1/10-scale R/C model car that hits 60 real miles
per hour. It's air-cooled, so you have to keep moving or smoke starts
to appear.
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Model boat glow engine, Traxxas, 2.5 cc, acquired 2004. This
is the upgrade for my Nitro Vee set-up, a 31" model boat that is driven
by a 42mm Cu/Be propeller. It is basically a Traxxas TRX 2.5 car/truck
engine, fitted with a water-cooled marine head and placed in a longitudinal
mount. It's a project to get going on one of these days.
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Leaf blower engine, Sears Craftsman brand, acquired 2002, 25 cc.
Bore = 35 mm, stroke = 27 mm. Takes 40:1 fuel/oil, and thus shares
its can with the string trimmer. This particular engine I've taken
from its worn-out housing, to display on my desk at work. Just clamp
it into the vise, hook up the tank, and use a model starter--it still works.
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Harvested Leaf blower engine, Sears Craftsman brand, acquired 2003,
25 cc. This is the same engine as in the entry above, only I cut
down the aluminum flanges on this second one and put in a radial plywood
mount for the purpose of turning an APC 16 x 8 propeller. This plant
is destined for my long-term model aviation project, the 80" Tree Hopper
5-channel R/C aircraft. It turns nice and reliably down on the test
stand in the basement; I relate the story as my resembling Al Lewis joyfully
exclaiming over an experiment as "Grandpa" on The Munsters, once
it finally ran. Jason Alexander really has taken a lot from Al Lewis,
in being the jovial New Yorker.
This is the larger-scale
.gif animation, a monster file of 710 K.
The original, 1:1 scale artwork on this design...
Depicted, in my imagination, is a generic 2-stroke design, exemplary
of which is the following:
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Displacement: 19.2 cc (1.17 cu in)
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Bore: 29 mm
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Stroke: 29 mm
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Compression ratio: 8.8:1
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Carburetor throat: 15 mm
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Induction: crankcase check-valve
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Porting: cross-flow
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Output journal diameter: 12 mm
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Wrist pin; crank pin diameters: 6 mm
I chose this particular size in an attempt to bridge the two major "worlds"
into which the consumer-grade, 2-stroke, single-cylinder engines are marketed:
glow fuel / platinum catalyst ignition, for models (a sort of hybrid carbureted
diesel); and gasoline fuel / spark ignition, for yard tools, etc., and
for larger models. A glow engine this size, at 1.17 cu in, is larger
than most sport radio control engines that are in use. These typically
top out at a .91. But by the same token, which I hope this mythical
engine to be, 19.2 cc is generally smaller than you'd see, for example,
in the smallest of gasoline / ignition engines, which get down to about
20 cc.
