the modded Didak Flow form 4

And there it is! Still weaving about a bit too much to get close to in 7-8mph wind speed but stable enough to KAP from a Sutton ff30. Following Christian Becot’s modifications to the ff30 the last thing to do is replace the outer shroud-lines with longer ones to soften the outer keel aspect, this should calm down the weaving. This shot shows the trailing edge vent working as well as the mesh insert maintaining the keel profile.

The objective, as with any kite for KAP is to get a slow, smooth, stable motion in the sky: ideally the kite should stay in one place absorbing airflow variation by flexing (the way Rokkaku kites do) or by channeling the flow (the Flowform principle), bowed sails, dihederals and foil-flexing are all used in kite design to achieve stability-this one now uses the flowform principle implied in its name!

About billboyheritagesurvey

Heritage worker
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9 Responses to the modded Didak Flow form 4

  1. jokerxl says:

    XL-ent job Bill.
    Do you modify all your new kites to this extent, or is this a particularly bad design to begin with?

  2. This one was something of a shocker. Most kites benefit from getting to know them before trusting them with a camera, so far the only one which has behaved ‘out of the box’ is the Becotised FF30 and that needs a drogue to work reliably. The minute this one did its 1st nose dive and I spotted it was missing the vents it was a case of replicating the working example I had in hand. The similarity between the Didak and HQ flowforms (they are both derived from Harald Prinzler’s plans) is such that all the bread-knife work had a good chance of success- it looks like a case of omitted details on the part of Didak!

  3. jokerxl says:

    Yes, it seemed like a lot of work, just to get it flying stable in reasonable winds.
    Mine flew great straight from the box, stable, predictable safe, except in too-strong winds where it keels over on one ear and commits Hari-Kiri into the dirt, but that is to be expected.
    It does tend to lean to (kite) right a little as the wind picks up and creep towards the corner of the wind direction to that side, when I’d rather it went more vertical.
    Would tinkering with the bridle lines help here?
    Also, would the side/rear mesh mod help on every kite of this type?

  4. The work done by Christian Becot on the Sutton Flowform 30 shows how effective venting the side keels is. The main value of this modification is that it reduces the tendency of the cells to collapse in cross-draughts. If your cells stay inflated as the kite moves sideways I’d leave well alone!

    A kite flying ‘on the ha’ is ( if it’s consistent) a symmetry issue. This is tricky because in tinkering you may make things worse in trying to rectify a minor inconvenience: flowforms should heel over to one side as they reach their wind-speed limit, there’s nothing you can do about this except be grateful you are not flying a parafoil which would invert at this point!

    You might try flying your kite off the shroud-lines or off a peg in the ground to explore the effect of tuning the bridle: pull on one side harder than the other and you will see the effect. You need to wait for the right wind to do this- an evening by the shore often gets you the smooth flow you need to fly on a short line.

    Your kite is a big one so I would expect it to reach its wind speed limit around Bft3. If that’s the case, like the golfer with a set of clubs, you will need to pick a different iron for Bft4!

  5. jokerxl says:

    I’ll leave well alone then Bill, tnx.
    It doesn’t do the collapsing cell thing and the leaning over is only when the wind exceeds it’s upper limit.
    Flies beautifully in 3-4bft, like a sky-hook, misbehaves in anything above 4bft.
    I have a 1,5m2 sled now for the stronger winds, didn’t have it with me in Australia, and may score a 7ft Rokkaku this very afternoon for the quieter days!

  6. Mike says:

    Hi
    I have recently bought this kite. I had a lot of bother recently with it diving sideways and have learn’t a lot from these articles.

    How did you cut the holes ?
    Do you have a “plan” of where they should be ??

    Regards

    Mike

    • Mike
      The layout of the holes was a scaled copy of the layout used on the (much heavier) HQ Flowform 2.0 and the rear vent was achieved by carefully unpicking seam of the 2 central cells. Despite all the mods I can only report that this kite is a poor second to the Sutton ff30 (2.7msq) original- I can now be confident it will stay up but its lift is not really enough for what I want it to do. Let me know how you get on!

      Bill

  7. Mike,
    Harald Prinzler (who is the originator of this type of flowform) has a good diagram here:

    http://www.hprinzler.de/ff04a.htm

    Harald Prinzler Ff04a

    good luck,

    Bill

  8. Pingback: Ultrafoil 15 mods for stability part 1 | Billboyheritagesurvey's Blog

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