Becotised Ultrafoil 15. Good kite, happy man.

ITW-Ultrafoil-vent-mods-9_12_2015The last one of these I did was for the HQ Flowform2.0 which uses a much heavier grade of fabric. For the Ufoil which I think is 31g/m Icarex I used a No.60 needle and a fine  polyester thread. Tulle is horrible stuff to stitch as it stretches as it feeds through the foot.

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The whole kite has to pass through the machine…

The keel cut-outs are scaled off the Becotised flowform and are filled with a light weight tulle mesh to maintain strength and shape to the keel. This is about as far as I can go following the Becot method: the only remaining stabilisation mods are to develop down wind drag effects from tail and drogue. These can be very effective but require lot of space to deploy and recover. The trees, hedgerows and barbed wire fences of the county await.

A response from ITW. As I work through the Becot method I have let ITW know about it and Mary Ann at ITW took the trouble to seek advice from Ray Merry (designer) and George Emmons (ITW proprietor) who are involved with the production of the kite. They suggest I’m flying the Ultrafoil at too close to its maximum wind-speed for stability. They looked at the video footage and noted the wind-speed at the height of the kite may well be close to the 30mph upper limit for it and the weaving behaviour is because of this. 2 suggestions to improve stability were offered:

  • 1. Fly higher to get to a smoother flow
  • 2. Add a longer tail

Unfortunately fly higher is not an option here in the UK as I’m limited to 60m. Short line oscillation is a problem for many kites and it appears ‘short line’ for the unmodified Ultrafoil in Bft 5 is longer than my flying height.

Duh! Adding more tail is perhaps what I should have done to begin with. I have been far too influenced by my experience with the Sutton, HQ2.0 and Explorer, which are stable flowforms without a tail, to consider this. I keep forgetting a tail is not a preference for many kites it is essential for stability in some designs.  The Ufoil is clearly designed to work with a tail as it’s supplied with one but, sadly, too short to stabilise the kite throughout its declared wind range.

Ralf Beutnagel says: “The tail should be seven-times the length of the kite for best efficiency.” The Ufoil 15 is 1.5m long so a suggested length is 10.5m.  The kite is supplied with a colourful 4.2m tail, so I need to find at least another 6.3m.

ITW stand by the 30mph upper wind-speed for the kite despite my experience to the contrary. I suppose you could say it will fly in a 30mph flow although it will wallow across the sky drunkenly as the wind speed approaches the limit for the kite.

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The mods work well. I doubled the tail. I am unsure as to which are the most effective or whether they work together a whole but at a peak flow of 25.2 mph (recorded at the kite, it was a mere 13mph on the ground) the weaving was absent and the kite at last kept a steady station in the sky.

I shot a short clip as I hauled the kite down:

It was a relief to see the kite move gently even in the low down rough stuff. The stable wind range is now increased to at least 25mph (Bft5)

At 60m it was good as gold and I was so happy I hitched a camera to the line and walked from Denver to Downham with the kite leading the way.

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The stabilisation is a great credit to Christian Becot’s work on the Sutton Flowform I’m grateful it works on the Ultrafoil too!

 

B

About billboyheritagesurvey

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6 Responses to Becotised Ultrafoil 15. Good kite, happy man.

  1. Piotr says:

    Actually it is very similar to S. FF16 with Becot modernization. Without these new holes it was much nicer! KAP people are, Nice Kite Killers! Marketing, marketing …
    Regards
    BKT

    • I can’t speak for all KAP people but this KAP person expects kites to behave, flowforms are the most difficult kites to work with and I’d hoped this one would be better than the rest, it isn’t. I expect selling kites is a different matter to using them as a photographic platform!

      The Ultrafoil is a popular kite and ITW sell it as ‘perfect for KAP’ it may well be if you want to wait all year for the honey sweet breeze or let your camera to bounce around in the sky like a pea on a drumskin the rest of the time.

      I use the flowforms for reach or when I’m out on the bike. I expect them to cope with what ever wind they find, but they don’t do as well as the delta or rok.

      Each new kite I fly has a new set of tweaks to learn to get the best out of it some are easier than others!

      B

  2. Piotr Mądry says:

    I spoke with Sandro SMAC, he personally is not completely interested in industrial kites. I think like him. But we both ourselves build kites for KAP. Kite only what I want is the dopero or rokkaku, JA. But I think my last constructions as successful. Rokkaku 10′ with a bizarre bridle is the best medicine in my area.

    BKT

    • Sadly I’m no kite builder, I’m too impatient to get in the air! My motivation is to get the camera in the sky and see the world from above. I always feel the need to take a better photograph.

      I know there are very few kite fliers who think like this. It is not enough for me to take any picture from the sky, from up there our world really can look its best and I feel I have a duty to do the best by it.

      I’d like to think that in wringing the best out of these kites better kites will follow but I suspect those selling kites would find manufacture to these standards more than the market can bear.

      I raise a glass to you, Sandro and Christian: the weavers of wind dreams, here’s to the dedicated kite builders!

      B

  3. too kind, thanks and all the best possible for the future of ALL PEOPLE dealing with KAP, with KITES,… SMAC from Italy

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