Peter Lynn ARCHIVE
Slarc 6, Single Line Arc, a Traction Kiting initiative.
It seems likely to me that in the future, traction kites will use radio control rather than multiple lines for steering and to set the amount of pull required.
A driving reason for this is that RC kites require only a single line.
This greatly reduces the chance of line tangles and snags which can be very dangerous for kite sports activities and especially on large boats using huge kites.
For kitesailing, a single line requires only a simple winch, which in turn enables kites to be flown at whatever altitude best suits each specific course and wind; - usually short line upwind, long line downwind.
For kite sports such as kiteboarding and snow kiting, using just one line rather than 4 or 5 will allow kites to be flown more than twice as high without extra line drag penalty; -jumps will be higher.
For kite buggying, less line drag enables better upwind performance and might therefore offset some of the dominating advantage that heavy buggiers and buggies currently have.
For all kite traction uses, radio control will improve safety by incorporating multiple and redundant safety systems- on the kite rather than at the flier end of the lines- so that any release does not further endanger those downwind with dragging snagging lines. It will even be possible to incorporate an override safety release that can be remotely accessed by observers for those occasions when the flier is unable to.
It occurred to me that this direction opens up a further possibility:
What if these RC traction kites could also have the added safety/convenience feature of being able to de-power, fly to their apex, and remain there when directed to, or as an automatic response in emergencies?
Kitesports could become mainstream and trans-oceanic kitesailing might become safe and practical.
There are two possible approaches to the development of such a feature for traction kites.
The first is an electronic automatic pilot.
Auto pilots for kites can be developed, but this will be difficult to do- and expensive. The principle is simple; - just hook a model helicopter gyro stabilizer to suitable servo operated control surfaces and in theory the kite becomes self apexing. In practice though, inertial effects and destructive feedback loops are major problems. Aeroplane auto pilots have taken more than 70 years and billions of dollars to develop but still only work for a narrow range of conditions- pilots turn them off when conditions look at all doubtful.
The second approach is to make a traction kite that in default mode, behaves as a single line kite, that is, self apexing. Even if electronic auto pilots are developed for kites, inherent stability and self apexing will assist their function. Luckily, Arc style kitesurfing kites do have some self apexing tendency, a good starting point.
Towards this end, Slarc 6 is the latest in a series (started'02) of Arc style kites developed to fly as single line kites and, with the addition of radio control for steering and angle of attack, as traction kites.
It's a good single line kite. Fully de-powered, it requires very little wind to stay up reliably, doesn't pull too much even when the wind is strong, handles turbulence well, and recovers directionally without excessive sideways movement, (marginally in strong winds, a characteristic to be addressed with Slarc 7).
It often appears to fly higher than 80degrees, suggesting an L/D at least as good as any dedicated traction kite.- and exceptional by existing single line kite standards. This could be an excellent choice of kite for altitude attempts. It also flies quite well as a 2 line kite, an unintended bonus.
A priority now is to develop some form of speed sensitive air brake to further damp down it's max. speed.
It has adaptive profile internal cording for profile changing, ready for servo winches and radio control.
It also should be scaleable to at least 300sq.m within current material constraints- for deep ocean kitesailing applications.
Peter Lynn, Ashburton NZ, Aug 16 '06
