Originally Posted by MAGGOT
I am also not sure of the turning radius numbers wise, but I can tell you that they are effectively shaped like old school straight skis.
|While that is probably true in a scientific sense, I am not sure the ffects would be big enough to matter when you're actually skiing.
The biggest impact of width on stability as far as I can tell is where it puts the inside edge in relation to the skier. We don't need a ski to be stable in roll, the mechanics of the body are very strong for controlling that compared to yaw. Consider for instance how well speed skaters do at very, very high speeds with essentially no roll stability built into their skates. I don't think its right to assume speed skis are wider because they are more stable that way. It might be because they are faster. Or both. Or neither.
If you want to say for sure
whether a narrower or wider ski is more stable in a straight line, you'll have to understand all the forces involved and the effect of width on them. I spent a few minutes on it this morning before class and didn't get very far...in fact I couldn't even convince myself that a typical ski is stable with a skier on it. Its obvious from seeing them run down hills that they are stable alone, but that is a far cry from what is going on when a skier is on them.
The more I think about it the more I contemplate that the skier/ski system might be a dynamically unstable system that we only keep from diverging with active control. I'm missing my copy of the Physics of Skiing, and I don't seem to be able to find any discussion of this on the interwebs at the moment.
Originally Posted by beyond
OTOH, if speed works anything like in boats, maximum speed is a function of the effective (running) length.
Unlikely this has anything to do with skis. You can relate boat length to maximum economic speed for a displacement hull because wave making resistance
is the dominant form of drag.
In a ski/skier combo, aerodynamic drag is dominant at non trivial speeds. The skier makes a wake as well, but we generally don't talk about "wave drag" in aerodynamics until we reach transonic speeds or portions of the body reach critical mach. Not even the dudes cruising the kilometro lanzado are anywhere near those speeds.
There certainly will be an optimum ski length and width for lowest friction, but what that is will probably vary a lot because snow varies a lot. We all know you can go pretty much the same speed down an icy groomer on SL skis as you can on GS skis if you point 'em, but on the other extreme we know that the big fat pow ski will let us go faster down a foot deep slope than a snollerblade.