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~ Home ~ Design ~ Specs ~ Photos ~ Tips ~ ~ Testimonials ~ Accessories ~ Contact Us ~ Soft vs HardWhat's different about sailing on a hard surface
By Robert Weber
Sailing on water is a science by itself. In the sixties, I was sailing the Austrian and German lakes and competing in the Kieler Woche on the Baltic Sea. The hot dinghy of the time was the "Flying Dutchman". My first model land yachts were fashioned around my experience sailing on water. Not until I took a jib from a 12 meter model and attached it to a wing mast did I get eyebrow raising performance. Then came the challenge to develop a hull on wheels. Like many new designs, I had a number of failures. I soon realized that the suspension and width proportions of the rolling carriage played a huge part in the over all performance I was looking for. My first truly successful model was built from the bottom up on principals I had learned from testing a number of hybrids. This model was named Stiletto. By this time, I had learned that a land yacht was not a sailboat on wheels, because the higher speeds afforded by really low rolling resistance, had definitely changed the science. That led to a number of compromises. The rig was a big challenge. High speed was not difficult to sustain, but changing the foil shape to accelerate rapidly was a real learning experience. I had to develop a way to "power up" the rig at low speeds to bring the boat up to its high speed capacity, and quickly. The Iron Duck (see NALSA.org), a full sized land sailer, which brought the land sailing speed record back to the US in 1999 (116.7 mph), used a solid symmetrical wing with no flaps. The wing was very efficient at speed but it took more than 10 minutes in a 30 + mph wind to reach full operating speed. You can imagine that this is not a good feature if you are racing on a course! So changing the foil shape became a major factor in developing rapid acceleration. So far, a wing sail aspect ratio of 1:3 has been the best combination for racing with the ability to accelerate rapidly and yet obtain ground speeds of 3-4 times the speed of the actual wind. With these speed capacities, it almost appears that the boat is developing its own wind/power - Perpetual motion anyone !? The wing sail proportion is coupled with changing the foil shape at the same time. At low speeds the sail portion of the "wing" acts like a flap and diminishes the importance shape cut into the sail. The rotating wing mast allows the skipper to change the shape of the foil, creating maximum lift at low speeds and then flattening out the foil as the boat accelerates. Thus high performance land yachts can tack up wind at 15 degrees to the actual wind and sail off the wind 165 degrees with the sail close hauled. Remember, at speed, a land sailer is going faster than the wind, so the apparent wind is always close hauled! Thus the sail trim is minimized and there is no down wind sailing, per se - and, no spinnakers!!! Another dilemma is weight. For maximum acceleration, it is important to keep the weight down. However, to keep the wheels on the ground and to minimize healing, more weight is needed. Thus began the development of beam versus ballast.
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