Tuesday, August 23, 2011
A Whole New Flying World
Even though ski flying doesn’t require an endorsement, it’s critical to get instruction first
Flying on skis is closer to flying on floats than wheels. So even though you technically don’t need an endorsement, you should absolutely get yourself some instruction before you just strap them on and go.
I’ve heard that the Inuits have over 100 words to describe snow. My vocabulary is much more limited. The variables that’ll have the greatest influence on your performance and technique will be the depth and consistency of the snow. Is the snow deep or shallow? Is it dry powder? Heavy wet? Crusty? Icy hardpack? Temperature will play a huge role in determining consistency. You can take off from hardpack on an early March morning, and come back to land on mashed potatoes in the afternoon. Heavy wet snow equals lots of drag, and as it becomes more on the order of a frozen slushy, you’ll get stuck. Shallow snow of around six to eight inches, or snow that has compressed itself or been matted down to hardpack, is great for learning. Deep powder that can sink the plane above the tail feathers should be avoided until you get some time under your belt. The same goes for pure ice and heavy crust.
There are three basic types of skis. With wheel-replacement skis, the wheel is removed and substituted with a ski. On a penetration ski, the wheel extends down below the ski for operation on snow and pavement. The retractable ski allows the ski to be retracted above or pumped below the tire, usually via a hydraulic pump. In my opinion, the wheel-replacement ski will give you the best performance due to overall flotation and light weight. They’re usually the least expensive, as well. On the downside, you’re pretty much limited to snow, although for many models, you can buy dollies to move the plane around on hard surfaces. The penetration ski will cost a bit more but offers lots of convenience. Downside: The tire sticking below the ski presents more drag and longer takeoff runs. The retractable ski offers the best of both worlds, but it usually means more weight, and plumbing can be a bit spendy.
All skis come with rigging, a front and rear check cable, and a bungee or spring. The check cables run from the tip and tail of the ski to tabs on the fuselage, and a bungee or spring runs from the tip of the ski to another tab. The bungee is there to hold the ski tips up in flight, and the cables are there to stop the ski from spinning around the axle if the bungee snaps. If you’re running in deep snow, then it’s advisable to run a tail ski, as well. In shallow snow a foot or less, I prefer to run without the tail ski because I can use the tailwheel as a brake if I need to by simply pulling back on the stick.
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