by Chris Woodford. Last updated: October 6, 2016.
Snow problem? 's no problem if you have a snowmobile!
If you live somewhere warm, like California, your only chance of seeing one of these brilliant little
machines is in wildlife documentaries or James Bond films. If you
live nearer the Arctic, in Alaska or northern Quebec, snowmobiles
(often called snow machines) will be as familiar to you as motorcycles
are to people living further down south. Given how useful they are,
it's hardly surprising that engineers spent much of the early 20th
century trying to develop the perfect machine for speeding over
frozen terrain. The small, light, modern snowmobile finally appeared
in the 1960s thanks to pioneering Canadian engineer Joseph-Armand
Bombardier, who named his machine the Ski-Doo®. So how do these funky
little snow bikes actually work? Let's take a closer look!
Photo: A convoy of US Marines on Ski-Doo snowmobiles in Alaska. Photo by Airman 1st Class Jack Sanders courtesy of
US Marine Corps.
What is a snowmobile?
Photo: Right: A snowmobile makes light work of this frozen track in Alaska. Note how far apart the front
skis are compared to a skier's: this gives a snowmobile stability
and a lower center of gravity, which helps to stop it tipping over. Photo by Jonathan Snyder courtesy of US Air Force.
Think about an ordinary motorcycle: you have a heavy engine in the center with the
rider balanced on top of it and two narrow wheels with
rubber tires just in front and behind. Now in theory you can ride a machine
like this through snow, providing the snow is soft enough to compact as you
move over it (and you can get some grip) and not so hard and frozen
that it's turned to super-slippery ice. In practice, motorcycling on
snow and ice is incredibly dangerous and best avoided: steering
fluctuates between tricky and impossible and there's a high risk your
bike will slide right out from under you. The problem is that
relatively little of your bike is actually touching the road—just
two tiny patches of rubber under the front and rear tires—and that's
simply not enough to give you good traction and grip.
Artwork: Left: A snowmobile gets much more traction in snow than a motorcycle using a large, wide
track with deep rutted treads. A belt-drive and clutch system transfers power from the engine (in the center of
the machine) to the track at the back. Compare this with Bombardier's early, 1944 snowmobile design (below) and you'll
see that the basic idea hasn't changed very much.
If you had to rebuild a motorcycle for snowy terrain, what would you change? You
might fit skis at the front to spread your weight and give reasonable
steering. A wide, rutted track at the back would give you plenty of
speed and lots of grip, no matter what kind of terrain you had to
deal with. What you'd end up with would be something like a modern
snowmobile. It's very similar to a motorcycle, with the engine in roughly
the same place and power transmitted to the rear track through a
More interesting features of snowmobiles
Photo: Who invented the snowmobile? This early snowmobile was designed by Joseph Armand Bombardier and patented in April 1944. Much like modern snowmobiles, this one has a ski at the front for steering and a sophisticated chain-tread track system at the back. Sprockets pull the tracks around, while idler wheels in between provide suspension. The main
difference between this vehicle and modern snowmobiles is the large cabin, which can seat about 12 people.
Artwork courtesy of US Patent and Trademark Office (with coloring added by us for clarity).
Skis, engine, a track, and some brakes—a snowmobile sounds simple enough. Under the covers, however,
there's a lot more going on. If you take a look at the 500 or so snowmobile-related patents that the leading
manufacturer, Bombardier, has filed since 1944, you'll find all sorts of features you might never have thought
of. For example, powering through wet or deep snow, it's quite likely the track will clog up, greatly increasing
the weight of the drive mechanism and slowing you down. That was why Bombardier developed a
snow-expelling mechanism in the 1960s,
which consisted of spiral grooved wheels to gouge out impacted snow as the track shuffled past them.
Some snowmobiles have retractable headlamps, which flip out of the way when they're not in use.
Again, it sounds simple enough, but someone at Bombardier still had to sit down and design a reliable
retractable head lamp assembly to make
that work. As you might expect, most of Bombardier's patents relate to the track/tread mechanism, suspension, skis,
and basic frame construction—the core features of a snowmobile—but it's interesting to
browse through their other innovations, which cover everything from
quick-release passenger seats
and engine turbochargers
to more mundane things like
electronic engine lubricators!
How safe are snowmobiles?
Snowmobiles are great fun but, like motorbikes, they're fast and heavy machines. In a typical year, 2 million people enjoy snowboarding in North America, but around 200 of them die in accidents and there are 14,000 injuries [Source: Snowmobile injuries in North America by J J Pierz, Clin. Orthop. Relat. Res. 2003 Apr;(409):29-36.]. Now 200 deaths might
sound like a lot, but we have to put that number in context. Each year, 130,000 people die from accidental injuries, 30,000 die from falls, and 33,000 die from vehicle accidents [Source: Accidents or Unintentional Injuries, Center for Disease Control and Prevention, 2013.].
Find out more
On this website
On other websites
- Snowmobile.com: A great resource for anyone interested in snowmobiles. Includes news, reviews, driving tips, events, and more.
- Snowmobile: The Wikipedia entry on snowmobiles has a lot of really interesting history and explains how small modern vehicles developed from much larger ones (though doesn't currently say much about how snowmobiles work).
- US Patent #2,346,351: Chain Tread Vehicle by Joseph Armand Bombardier. This is Bombardier's original snowmobile patent (filed July 6, 1942 and granted April 11, 1944), including the drawing you see here, and it explains in detail how the suspension works on the tracks at the rear.
- US Patent #2,702,088: Snowmobile by Marcel Klimek, Jr. This later patent sketches out a one-person "motorcycle-on-skis" type of snowmobile, similar to modern designs.
- US Patent #3,023,824: Endless track vehicle by Joseph Armand Bombardier. The classic track-and-ski snowmobile, patented by Bombardier in the early 1960s.
If you liked this article...
You might like my new book, Atoms Under the Floorboards: The Surprising Science Hidden in Your Home, published worldwide by Bloomsbury.