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DESIGN CRITERIA

Wide Short Ski Patent #  5,603,522  Issued Feb. 18, 1997

The following dimensions define the area of maximum energy efficiency for an all-terrain ski, in the main claim of the patent, although  we feel there is additional area surrounding these dimensions that should be included in  this basic design.   These dimensions are grounded in the physics of conservation of surface area and edging power, and increasing balance equilibrium, while reducing extraneous torque and swing weight.

Exact  Dimensional Criteria in Patent Main Claim

There are extended measurements around these dimensions that perform as effectively and that area I also claim in my patent.   This extentend area is between 1-5%

 width shovel

 110 mm to 120 mm approx.

 width waist

  determined by sidecut radius

 width tail

 105 mm to 115 mm approx.

 length range

 148 cm to 173 cm approx.

 sidecut radius range

 14 meters-28meters
  (10 to 16 times 
    overall length)

 surface area

  1300 sq.cm  to
  1600 sq.cm


Skis designed within these ranges with a waist range of about 74mm on up will eliminate "boot out" while moderating the shaped ski's tendency to bock into a carve..

 

As was noted in affidavits, a deep sidecut in a shaped ski doesn't relegate that ski to carving efficiency only in short-radius turns.  However... to do both efficiently, it should be flexed more firmly than the norm for a narrow waisted recreational shaped ski of comparable length.

How firm?
Since 1992, when we introduced our first limited run production model of ODYSSEY MAX/FX, 163 cm, we've designed skis in several flexes, from 43 N/cm (about 25lbs/inch deflection, for skiers weighing 120lbs-140lbs), up to about 77 N/cm (about 45 lbs/inch deflection) for skiers weighing 220 lbs on up.  This flex range interestingly enough, is about the range of flex that the manufacturers make for downhill racing skis, dependant upon the weight of the individual racer.

For Comparison purposes
The ODYSSEY used in winning a Slalom race in 1994 were flexed at 64 N/cm (about 37 lbs/inch deflection).  Those dimensions were:   159 cm X 112 mm X 82 mm X 105 mm, Sidecut radius 17.7m.

Our 1992 Production model of the MAX/FX {163 cm}  that Howard Bade used  for demos and to shred the big dumps of powder with up at Mt. Baker was flexed at 45 lbs/inch.  In other words, a ski designed for soft snow doesn't have to be of a soft flex.  Even at the upper limit of waist width for all terrain efficiency of the MAX/FX or 99 mm, a firm flex generates a lot of carving power and stability, not just for groomed outruns, but also for powder and crud.  In a mid-fat firm flex is an asset not a liability. It provides a more stable, predictable platform.

Shaped skis with narrow waists (62-68 mm) have an inherent design flaw that makes them  unsuitable for all-terrain skiing.   The main area of the ski underfoot ( the sweet spot), which includes the binding, does the lion's share of the work during a skidding or pivoting maneuver.  This is also the area of the ski where most of the balance feedback originates during the transition from turn to turn.  This area in a narrow-waisted ski is just too small.

By way of comparison on 82 mm waist shaped ski has 32% more surface area and width in this "sweet spot" than a 62 mm waist shaped ski but the energy efficiency starts tapering off below 82mm.  It quite simply requires less muscular energy to balance on, and pivot on.  This factor in energy savings is compounded with every turn that is made.  Fatigue is accumulated at a much slower rate than with a narrow-waisted ski.

What this means is that diminishing balance caused by fatigue slows down.  There is in turn a slow down of  the cycle of increased fatigue from overworking the muscles used.  For balance, what always happens, at different rates depending upon physical conditioning, is the more fatigued one becomes, the longer one's balance reaction time becomes, multiplying both the intensity and duration of muscular exertion needed to recover one's balance.  This in turn causes more fatigue...and the downward spiral of fatigue and loss of balance continues..

The much slower rate-of-fatigue-accumulation factor that mid-fat shaped skis have over skinny-waisted shaped skis brings with it another advantage,  SAFETY.

It's a well known statistical fact that more injuries and/or accidents occur in skiing as the level of fatigue increases.  Add to this fact that mid-fats in ergonomic length (under 180 cm) don't require as high of a binding DIN setting for boot retention as skinny waisted shaped skis of comparable surface area.  The result:  Mid fats are more likely to release in a slow twisting fall.

Physical Elements of Skiing
Skiing can be broken down into 3 basic elements that require physical energy and effort.

The basic elements are:
Element one-  Balancing
Element two-  Changing direction
Element three-  Checking speed, and/or stopping.

Mid fat shaped skis based on the most energy efficient design criteria (over 80 mm waist, under 180 cm-length) decrease the energy demands placed on a skier by the first two elements: one balancing, and two changing direction, than narrower wasted, longer skis.

The third element:  deceleration, and, or stopping, requires a great deal of energy, and physical power, proportional to the G-forces produced in how quickly one decelerates or stops at the end of a turn.

There is no escaping the demand of energy or physical power required to execute a high G force carve or stop (element #3).  Only physical conditioning, strength training and practice can get you to the level you want to be at in element #3.   Be this as it may if you are using less energy in elements 1 and 2, by using the correct ski, you are going to have more energy left for the demands of element number 3.
 

How to measure a skis longitudinal flex
Locate the forward and rear contact points of the ski (the point where the bottom of the ski begins to curve upward toward the tip and tail of the ski, respectively).  On average, the forward contact point is about 7 to 8 inches from the tip of the ski, and the rear contact point is about 2 to 2 1/2 inches from the tail of the ski ( a bit more in a twintip).

The deflection of the ski, given as the spring constant is derived by suspending the ski, base side down, on these points (tall blocks of wood work well, placing a weight at the mid point between the two contact points, and dividing the amount of weight used in pounds by the amount in inches that the ski was deflected by the weight.  The more weight that is used, up to about 1/2 the average skiers weight, the more accurate thespring constant.

If, for example, the weight used was 100 lbs, and the ski was deflected 5 inches, the spring constant for this ski would be 20 lbs/inch (Olin Outer Limits).    If you need more instruction on this feel free to e-mail me.


 


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