On Parafoil kites- the pure form

I have been a fan of these for years, I still have the Premier 7.5 and it flies well up to Bft 3, beyond that it might as well be a paper bag in the wind, it flops all over the place and pulls like a horse as it careers around the wind window, it’s fun because its easy to launch and very tidy to pack away too. I bought it from the Kite shop in Covent Garden in the early ’80s as a consolation for a lost parafoil… it was a case of clinging on to the idea of a fun kite after the painful discovery that big is not always better with these things. The lost kite was  a 20 sqft Morgan kites monster in fluorescent green. In those (pre digital) days it never occured to me to hang a camera off a kite: I was just gripped by a recurring desire to colour the sky with various wind weeds.
I have never understood why flying a kite often places the flier in a peacefull state; partly it is a distraction from worldly things brought on by the mental focus on wind, lift and line and partly the placing of the flier in the landscape. There is at once the possibility of falling from the sky and at the same time the triumph  over it.
Domina Jalbert’s idea of a soft wing  formed by the wind  has a design purity few ideas (with the possible exception of Leo Fender’s Telecaster) of the 20th Century have surpassed. Minimum weight, maximum lift and a from derived from function.
The parafoil is a very radical idea, kites have evolved around the ‘stick and skin’ principle from the start, Jalbert responded to an intersection of technologies and materials and the parafoil was born in 1963: it would not have happened without his experience with parachutes and balloon manaufacture combined with his flight awereness as a light aircraft pilot.
The power of the parafoil is its strength but also its weakness, stability in parafoil design is very difficult to achieve across a wide windspeed range.  Once its overturned all its power works in reverse! Steve Sutton’s  adaption of the design in 1979, again derived from parachute development,  extended the wind range of the parafoil by venting and he gave us the flowform.    The flowform is probably the best parafoil we have for KAP until Ralf Beutnagel’s KAPfoil. Ralf took apart all the parafoil designs he could find, tested each one for lift and stability, analysed the chords, worked out the optimum aspect ratio and the result is a really stable kite, unfortunately, to date, it is produced in hefty sizes- 5 msq is a big kite for me, even in a light wind (where big is best) 4m is the biggest I work with.
For me the great advantage of the ‘soft kite’ is its utility- no assembly is required and I can pack 3 or 4  different sizes easily on my bike, I can use a variety of line weights if I need to and the relatively low flying angle gets me over my subject nicely, not worrying over breaking spars is a big benefit too. The downside is the stability issue, a Rokkaku won’t go into an unrecoverable spin in a rotor and if it does slip it can be controlled without fear of collapse- an upended or slack line flowform needs quick thinking and a fair amount of luck to recover. When they fly well they are the best thing I can think of for KAP but inversion of any kind of parafoil is a dangerous situation best avoided by matching kite, drogue and line to wind speed.   Flowforms do better than ‘pure’ parafoils but they still need watching with a careful eye!
I’m having lots of fun getting to know the Explorer, it doesn’t lift like the Sutton but now fitted with a ‘Y’ tail it keeps a steady spot in the sky. This clip is taken from a flight in 5-11mph Easterly which was dirty enough to upend the Sutton (which was flying without a tail..I only have the one drogue at the mo, a tree ate my last one) but not the Exlporer.
I wonder if I should have got a bigger one than 2.7 to match lift of the Sutton ff30.
George Webster has published an excellent overview of soft kite development here
You will find truth more quickly through delight than gravity. Let out a little more string on your kite.  Alan Cohen

B

About billboyheritagesurvey

Heritage worker
Gallery | This entry was posted in KAP, Significance, value and society and tagged , , . Bookmark the permalink.

2 Responses to On Parafoil kites- the pure form

  1. wesleycarter says:

    Kites are one of my favorite things in the world! Thanks for refreshing my lust for the one kind, I do not have. 🙂

  2. Pingback: Getting to know the Didak Explorer 2.7 | Billboyheritagesurvey's Blog

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