Today was the last on-snow day for the US Ski Team at their early May on-snow camp at the Callaghan Valley Olympic Venue. Things have been uncharacteristically busy for this time of year since my last post. I had a short trip down to Boulder to meet with Nathan Schultz to begin planning for world domination. We realized that we couldn’t quite flesh out the plans for primacy in four days, so I convinced Nathan to come up for another four days of nefarious plotting, along with groomed skiing, checking out the National Team camp, etc.

One of the most interesting aspects of the trip was the opportunity we had to look closely at some really special national team skis. It’s one thing to hold these skis in your hand, or wax them at a World Cup. It’s another thing to put them on the flex bench when they pass through the shop for grinding. But it’s quite a special opportunity when you can ski them on snow, and do a comprehensive flex evaluation on the same day. And to add yet another dimension to the experience, Nathan brought along a pressure-mapping tool on-loan from Andy Gerlach of Endurance Enterprises.  This gave us the chance to compare our more rudimentary flex bench evaluations with extremely precise pressure mapping of the ski, and to correlate all of this with what we’re feeling on the snow.

The mind boggles at the possibilities with such a set-up, and I was prepared to be disappointed by our inevitable inability to quantify what makes a great ski great. In the end the whole experience was fruitful and reassuring. One of the major (if somewhat generic) findings we had was that the evaluation protocol that we’ve developed works very well. We use flat aluminum flex benches with a known load applied through a single loading point. As part of our evaluation process we check the load and pressure distribution characteristics using feeler gauges. It’s a process that relies heavily on tactile feedback, and it’s taken quite a long time for us to make it satisfactorily reproducible. I’ve always wondered how close we were getting to generating an appropriate picture of what’s actually happening under the ski. Looking at pressure distribution maps of skis that we’ve previously evaluated using our system was extremely reassuring. We’re doing better than an approximation - we’re pretty much hitting the nail on the head. Our evaluations of the high pressure zones of the ski are exactly on the money with what the pressure map shows us with the athletes actually standing on the skis. Furthermore, our evaluations of the change in pressure distribution with changing loads is appropriate, and our more subjective assessments of the “shape” of the pressure distribution are also quite good. Fantastic! Self-congratulations all-around.

So what of the question of quality? Can we spot a great ski a mile off, using our own home-grown evaluation method? Nope. We’ve still got to put skis on the snow to find out which ones are truly special. One pair that we examined - Kris Freeman’s best skate skis (in whatever conditions they’re ground for) had an interesting pressure map. It’s only distinctive characteristic was its “cleanliness” on the map. There was nothing particularly special about the position or depth of the pressure zones, but the transitions to and from high pressure were smooth and clean.

When I first started looking at design options for a more advanced flex tester a number of years back, the best-established design out there was one that placed load transducers every 10 cm or so along the length of the ski. At the time I felt that the tactile evidence that I had, based on looking at a lot of skis using the method I had developed, indicated that the transitions from low pressure to high pressure were often extremely short and quick. One data point every ten cm seemed insufficient by a long ways. Instead I sketched a design that made use of one load transducer that would pass under the entire length of the ski, taking measurements however frequently we decided we needed them. Ernie Day helped me spec the instruments and drew-up the plans for this new flex tester. Ultimately, we got the thing most of the way assembled. It’s now in Boulder, where Nathan is working on automation and data collection. This machine is a colossal undertaking for a bunch of ski guys who happen not to be robotics engineers. So far we’ve got almost $10K invested in it - with a lot of free consultation and time thrown in by Ernie. There’s quite a lot of work yet to be done, and once the thing is “finished” we’ve got to learn to use it. Fortunately, we’ve got a better idea than ever what we’re looking at, and what we’re looking for, when we look at race skis. We haven’t exactly been mowing-through the process of getting this rig operational, but it’s high on our list of priorities in our plan for world domination.

At this point you might well ask why we don’t just make use of the technology that Andy Gerlach loaned us. The Endurance Enterprises flex mat is a truly powerful tool. I did, in fact, consider this technology when I first started looking at designing a new flex tester. My feeling was that it was overkill, and would present major problems in terms of quality control and repeatability. The flex mat is clearly the best tool available for looking at the pressure distribution of a ski with the skier standing on it. Given another three weeks to work with the National Team we could learn a lot more, I’m sure. And as a retail aid it is an amazing way to illustrate a description of the way that skis work. But it’s a finicky piece of equipment and seems to undergo calibration shifts continuously. Its ability to illustrate real-time changes in load and pressure distribution is fantastic, but it would be an incredibly slow and data-intensive way to evaluate a large quantity of skis. Also, it offers no capacity for evaluating camber height and action, which is at least 50% of the final equation. So I’m pleased with the direction we’ve taken in the design of our next-generation flex tester. More back-patting.

So, Nathan flew home this morning, and the USST heads out tomorrow. We’ve laid the groundwork for World Domination and we’ve both got a lot on our plates to bring the plans to fruition. In the meantime I’ll be heading back East on the 17th for a visit, and to clean-up the mess I left behind when I moved out here. I may get on-snow once or twice more in the next week, but then, I may also decide to focus my attention on the mountain bike trails around here which are in need of some serious taming.