Tiny Outboards Howl Like the Big Ones
July 1954 Popular Science

July 1954 Popular Science
July 1954 Popular Science Cover - RF Cafe[Table of Contents]

Wax nostalgic over early technology. See articles from Popular Science, published 1872 - 2021. All copyrights are hereby acknowledged.

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