Peter Bults very kindly suggested the Colours in Motion ‘Lifter’ http://www.coloursinmotion.de/ as a stopgap for the Sutton Flowform 30.
It certainly is good value for money, well made and of a nice light grade of ripstop. It’s design has important lineage in the form of the Peter Lynn KAPpilot. More info on the KAPpilot is here: http://www.kaper.us/basics/pilot50.html
It became immediately clear that it needed a tail as it wove wildly across the sky and dumped itself into the dirt. Second launch with a drogue 5m behind it got it sitting a bit better in the sky. The kite wanted to sit heeled over to the right. A bit of shroud line adjustment should sort that out, so we watched to see how it behaved compared to the trusted Flowform. It has a strong tendency to track across the sky, pulling harder as it does so, but when it was in the eye of the wind the pull dropped dramatically, the shroud lines slackened and the kite began to drift before beginning another tack to the left or right. My thoughts on this are that the kite is being pushed about by the wind bouncing off its leading edge (a suspicion confirmed by watching the tops of the intakes buckle in gusts). Clearly this is a parafoil, and I think the movement is something of a chracterstic of the type; the kite fills with air which then acts as a block to airflow at the leading edge. The Sutton Flowform design deals with this in 2 ways.
1.Venting: by letting the air flow through the kite it becomes part of a directed ‘jet’ of air rather than an obstuction to it.
2.Pressure relief holes: by balancing the pressure of air inside the kite with that around it only sufficient pressure to maintain inflation is maintained and the high pressure build up at the leading edge is avoided.
Steve Sutton’s patent drawing of the flowform design shows the care he took to balance airflow throughout the wing- not just over and under it. The pressure relief holes are arranged so that there is not a direct path from entry to exit and therefore the risk of pressure failure is minimised.
Taming the Lifter. The next steps are to balance the shroudlines and then begin a gradual introduction of vents and holes to see if the kite can be stabilised. This will of course need testing in low wind speeds as well as brisk ones so this is going to take a while. I suspect the methods Christian http://www.becot.info/tako/anglais/e&tako_1.htm used on the Flowform will also apply to this kite, but it has some really big problems to sort out before fine tuning.