Want a dual-line kite that "FLIES" really well?

Look for a kite that doesn't flex or deform out of shape as it FLIES

Why? Flexing or distorting out of shape = losing performance = losing straight-line speed & pull + losing turning speed & power = losing out on fun.

Straight-line flight

As a kite FLIES across the flight envelope, bridle lines pull on the kite directly towards you. Simultaneously, aerodynamic lift (the "pull" you feel) pulls on the kite from the opposite direction, directly away from you.

The bridle-line forces and the aerodynamic-lift forces pull on the kite from opposite directions and in different places. This can cause the kite to flex and deform out of shape. The stronger the forces and the more flexible the kite, the more the kite distorts out of shape.

As the kite flies from the edge to the power zone, those forces can rise 20-fold. When the wind speed doubles, those forces can rise 4-fold. When the wind speed doubles while you fly from the edge to the power zone, those forces can rise 80-fold.

Suppose you have an 8-ounce ultra-light dual-line delta. To see the effect of bridle and aerodynamic forces that vary from a few ounces to 100 pounds as you fly, hold the kite upside-down by the two bridle lines and have someone place ten 10-pound bags of sugar evenly on the sail. See how the shape of the kite can dramatically change as you fly?

Those shape changes cause a kite's aerodynamic efficiency (lift-to-drag ratio L/D) to deteriorate, which causes loss of speed.

Those same shape changes cause the "bridle-setting-required-for-top-speed" to change. Since you cannot be up there on the flight envelope constantly re-adjusting the bridle to its optimum setting as the kite flies along, the bridle is out of adjustment most of the time which causes additional loss of speed.

Maneuvering flight

While turning, a kite can deform out of shape in a manner that reduces its speed & pull.

Specific characteristics to look for in good dual-line kites

All parafoils, with & without spars: As the kite flies from the edge to the power zone in light winds and in strong winds -- and as the wind strengthens -- the flyer-view wing shape and the head-on-view wing shape must not change. The wing's shape during a sharp turn or tight spin, including the head-on-view shape, must be the same as during straight flight. The kite must have a wide wind range within which it FLIES at high performance, the kite must not change shape in any way as the kite's speed or wind changes, and it must not need different bridle adjustments for different winds.

Deltas: As the kite flies from the edge to the power zone in light winds and in strong winds -- and as the wind strengthens from light to strong -- spars must not bend at all, the sail must not change shape at all, the head-on-view shape of the kite must not change, and no flutter of any kind must develop. The wing's spar-and-sail shape during a sharp turn or tight spin must be the same as during straight flight. The kite must have a wide wind range within which it FLIES at high performance, the kite must not change shape in any way or flutter in the least as the kite's speed or wind changes, and it must not need different bridle adjustments for different winds.

Look for the performance benefits of a kite that doesn't flex or deform

• Large kites fly faster than small kites (as they theoretically should).

  But for virtually all types of kites, the opposite is true: small kites fly faster than large ones because the large kites have higher relative distortion.

• High aspect-ratio kites if they're correctly aeronautically engineered, wing-area for wing-area, develop more pull than kites of lower aspect-ratio (as they theoretically should).

  But for delta kites, the opposite is true: low-aspect-ratio kites develop more relative pull because the high-aspect-ratio kites distort relatively more.

• Superior edge to power-zone acceleration.

• Superior responsiveness to the wind: when the wind kicks in, the resulting acceleration, speed, and pull are higher.

• Higher speeds overall.

• Higher power-zone pull, wing-area for wing-area.

• Livelier, more-dynamic pull characteristics.

• Bridle-setting changes are not required in order to achieve optimum performance in different winds.

• Any kite that doesn't flex or deform out of shape has an ultra-wide wind range. Any such kite is both a good light-wind kite and a good strong-wind kite. A large kite, when flown in strong wind, will not deform or break and will fly with tremendous speed and awesome power. So will a small one, but with a little less speed and a lot less pull. Small kites and large kites of the same type and design fly about equally well in all winds -- when flown in the same wind, the main difference is in the amount of pull.

• Higher speed and more pull during turns and spins.

• Overall, a livelier and more-exciting feel of wind and kite through your flying lines.

Look for these other great FLYING qualities

• Perfect tracking. Precise control. No oversteer or understeer or skidding during turns. Sharp square-corner turns with no after-wobble-&-weave whatsoever.

• Pull rises whenever you steer & turn -- "increasing-resistance steering & turning" that provides "positive steering & turning feedback." This nice feel is normally engineered into virtually everything that moves (except for most dual-line kites) because it enhances control, accuracy, and feels so intuitive & natural to the user. Besides seeing where the kite goes, you feel where it goes -- even during subtle corrections. And it sure helps beginners to learn rapidly! "Increasing-resistance steering & turning" also makes a kite feel solid during a turn, provides speed and power during a turn, and provides a high-performance turning response to basic tension-generating skill.

  The force RISES when you turn like when you snow ski, water ski, ride a bike, or fly an airplane. Besides feeling exciting, in a kite this feel is familiar which helps beginners learn rapidly.

  Many dual-line kites have the opposite feel -- the pull drops whenever you steer & turn. Such kites feel vague and powerless when you turn them, and respond poorly to normal basic skill such as pulling hard on one line to make the kite turn fast. Because the steering and turning feedback is negative rather than positive and because the feel is the opposite of what feels natural, kites like these make learning difficult. Avoid them.

• Ultra-forgiveness. While flying, drop one handle. The kite should keep flying. Suddenly yank long and hard on one flying line. The kite should keep flying.

• Superb speed & power response to turning input: Using basic kite-FLYING skill, suddenly yank long and hard on one flying line (the other one goes totally slack) with such violence the flying line almost breaks. The kite should spin extremely fast, tightly, and powerfully -- and should not even come close to flexing out of shape or breaking.

• Superb edge handling: In light wind, the kite is in a stationary hover at the side edge of the flight envelope with the lower wingtip one wingspan above the ground. The pull in the flying lines is near zero. Using basic kite-FLYING skill, you should be able to hairpin-turn downward into a ground-level pass toward the power zone.

• Really fast speed and quick & sharp turning: Such as the WindDance 1 at play in 20-30 mph wind with 75 ft flying lines, the experience I (Dan) had at the close of the 1997 Long Beach WA International Kite Festival. I reduced the bridle setting by 0.5 cm from the sane-wind peak-performance setting to keep pull below the kite's Rated Pull Strength of 100 lb. Even then it was FAST! Edge-to-edge passes took about two seconds, one second from the edge to the power zone, one second from the power zone to the edge, average speed around 70 mph, power-zone speeds about 100 mph. The kite shrieked as it ripped through the air. The loudness and pitch rose as it neared the power zone, and whenever I turned fast. Every time I flew toward the power zone I got yanked. Pull-turns anywhere near the power zone were out of the question because the pull was so strong when I turned that way. So I quickly clued myself in that I had to punch-turn to lower the pull if my body was going to survive more than 15 minutes of such fun! After a few minutes of practice, I was able to punch-turn sharp square corners in the power-zone. But only one at a time because things happened so fast I had no idea where the kite would be headed after a second corner. "What about doing a simple 10 ft square in the power zone?" I asked myself. 1/8 second per side, 1/2 second to do the square. Hmmm, that's awfully quick. From the sharp square corners I already punch-turned, I realized the kite could do it. But I couldn't because my nervous system doesn't operate fast enough. Top competition flyers, they're much quicker, could do it though. So I tried something else. From the upper edge, I dove to the power zone which took one second. Just before impact, I punched a really-tight hairpin turn so fast I could barely see the blur of the kite, then it zipped back up the edge, a two-second round trip. I did it again and again, closer and closer to the ground, quicker and tighter hairpin turns. I threw my entire body into those incredibly fast-&-tight last-instant pullups. The kite's high-pitch shrieks were loud during those hairpins! At those speeds the WindDance flew more than six feet in 1/25 second, and a few times my timing was off a little: I began some pull-ups more than 1/25 second too late! The crashes and bounce-'n'-flies were really loud! What a rush!

WindDance dual-line parafoil stunt kites/sport kites are developed, sold, and backed by Seattle AirGear.
WindDance, WindDancing, Seattle AirGear, and AirGear are trademarks of Seattle AirGear.
Copyright © 1995-2017 Seattle AirGear.
This page last revised Sep-5-1998

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