|
Ahhhh, the days before
electric powered everything. I will be the first to admit that the ease of
operation, cleanliness, and quietness of an e-powered model is convenient and
helps keep neighbors happy, but the undeniable fact is that from a motivational
perspective, nothing in modeling compares to a screaming internal combustion
engine (ICE) with blue smoke pouring out of the exhaust - especially when no
muffler is installed. Go on, you can admit it, unless of course you have never
partaken in that aspect of our hobby. When I was a kid, if I could hear even the
slightest hint of a glow engine running, I'd be on my bicycle pedaling as fast
as I could toward the source of the beautiful sound. Sometimes it was a kid down
the road with his Cox tethered car, or on rare occasions a fellow model airplane
flier. A man a couple blocks away flew R/C airplanes and helicopters, and my
sudden presence every time he started up an engine probably made him cringe
(although I did stay out at the street unless invited over). I would be content
to sit on the side of the road and listen to the engine run and if lucky, get a
whiff of the exhaust. I've told Melanie that if I ever lapse into
unconsciousness and cannot otherwise be revived, fire up a Cox .049 in front of
me or wave a spent Estes rocket engine under my nose. I there still is no
response, pull the plugs on life support and make plans for my burial.
Tiny Outboards Howl Like the Big Ones
As the bow drops to planing position, little model lights out.
Actual speed may be near 20 m.p.h.; scale speed over 100.
Water-Cooled version gets its circulation from
the pressure of water astern of prop. The air-cooled version (right) works well
on open hulls. Note in cutaway engine that this make (Atwood Motors) uses a flexible
shaft to get power to prop. Photos above are half life-size.
If a small but perfectly formed outboard hydroplane, only a few inches long but
able to scream nastily, overhauls you on the lake one of these days, there's no
need to count your marbles. It's just one of the tiny new outboard models - latest
adaptation of that incredibly tough little power plant, the model-plane engine-that
have been delighting duck-pond sailors this summer.
Weighing less than five ounces complete, such an outboard has a genuine internal-combustion
engine. The bore is roughly the diameter of a lead pencil; the stroke about the
length of the eraser on the end; the displacement a piffling 1/20 of a cubic inch.
Despite these mouse-scale dimensions, the tiny two-cycle job spits out about 1/32
hp. at 14,000 r.p.m., which can take a 14- to 24-inch boat up to 12 to 25 m.p.h.
Oops! After a porpoise start, this model settled down to a fine
high-speed run. Motor is often angled to drive boat in a large circle. Gas tank
gives about a two-minute run.
Like the Big Ones, some tiny kickers have two
bevel gears in the underwater unit. This one, the Allyn Sea Fury, has rustless drive
shaft and chrome-nickel bevel gears, driving a high-speed prop less than an inch
in diameter. Adjustable mounting bracket suits various transoms. Needle valve gives
speed control: extra-rich setting slows up the engine.
Fuel is a mixture of methanol, castor oil and other agents. Ignition is by glow
plug, a bit of resistance wire that's electrically heated for starting. The engine
then carries on by self-ignition. Die-cast parts of light alloy account for both
the light weight and low cost-under $10. Hobby shops are stocking, besides the engines,
suitable hulls and hull kits.
Cautious owners run their craft tethered; more daring sailors try trans-pond
"free-flights" or big semicircular cruises. How do you stop it after a run? A cinch
- just pinch the flywheel - Jack Wilson.
Posted April 6, 2024
|
