Hey Bears: Thanks for the great responses thus far!
I feel like maybe the issue's getting confused, which is easy, since there are so many variables involved in how a ski feels. Let me iron out a few details to narrow the discussion, if that's all right...
First, to answer Sluff Vertigo:
by "distorted", I mean that the material making up the plane of the ski must be either deformed out
of plane, or rotated around its axis within
that plane, in order for the ski to flex. "Flex" covers longitudinal as well as torsional bending--the two ways a ski's material behavior influences our experience of it. And I say "two ways" because a ski generally does not get compressed or extruded axially, to any appreciable degree. So at the micro-level, the (various) material(s) of the ski must be deformed or distorted in order to allow a general flexing or bending--globally.
Another, separate category of influence is a ski's geometric characteristics--its length, sidecut, swing weight, etc. The macro-level stuff. PhysicsMan
was admirably picking away at such variables in his earlier post, and while I was positing modulus of elasticity-type factors, he was adding in moment of inertia and lever-arm-type arguments. And they were good ones. I actually think they might be sorta kinda the answer--but more on that later...
Probably most important, though, is that, as PhysicsMan
noted, my initial premise might just be off base to begin with. I, frankly, don't actually know whether or not the general concensus is that fat skis 'ski longer'. Establishing whether or not that's the general perception out there would be good, for starters. It's partly why I asked.
Secondly, if it IS the concensus, we really would benefit from eliminating the other variables, mentioned in a few responses; to wit:
|Fat skis are usually softer than race skis, especially, so that they are easier to turn in soft snow.
|ski manufacturers do in general start the fatter skis with longer length than shorter ones.
Well, yes, manufacturers obviously can create practically whatever they want: a stiff fat ski or a soft one; a stiff race ski or a soft one. A short one or a long one, etc. This is um..immaterial (sorry) for the purposes of the discussion. We're not talking about soft long fat powder skis vs. stiff short skinny race skis. That's classic apples and oranges.
The pertinent question is, would two skis of identical length, construction, and sidecut, --differing only in width--
ski noticeably differently?
It's a hard one to answer, I guess, since very rarely does a manufacturer vary only the width of a specific product while keeping all else equal--unlike, say, length,
which is often varied while all else remains the same. Unfortunately, you sort of have to assume that manufacturers are commonly varying both the mechanical
properties of their products all together at once. Very unhelpfully, I might add.
IF you want to get to the bottom of things, that is.
So it may be an impossible question to answer, due to a lack of data--of apples to compare to other apples.
And therefore maybe there is
no definitive answer, other than hair-splitting theorizing, anyway.
/Tom: I think that your propositions are definitely valuable items for discussion. While I would guess that your #'s 1 & 3 would indeed create a qualitative difference, I agree with you that Joe Average Skier would correlate this sensation more with other perceived characteristics like "stability" than with what I would guess are the sensations involved in a ski seeming to "ski longer." That's just a guess, though. And anyway, this is all based on secondhand, subjective, and anecdotal impressions I've gathered from some pretty undisciplined minds out there in skierville.
Your #2, though, would
seem to fit within the picture I've had painted for me. If a ski is a bit harder to get up on edge due to reduced moment arm, then it seems like it would be "slower" and harder to bring around from turn to turn, i.e. it "skis longer". It wouldn't be a big difference, but it might be noticeable--humans are pretty (unpredictably) nuanced in their perceptions, sometimes.