IMG_9993 IMG_9971 IMG_9957 IMG_9925 IMG_0069 IMG_0065 IMG_0063 IMG_0057 IMG_0053 IMG_0048 IMG_9999

This nadir shot was taken as the kite over flew its own line….

  • Camera flight time 15mins
  • 236 exposures captured.
  • Shot interval :5s
  • Path: clickPanPro ‘A’
  • Canon S95
  • Exposure: CHDK KAP UAV 3.5
  • Shutter release: USB one shot
  • Tgt Tv: 1/1000
  • Min ISO: 100
  • Max ISO: 800
  • Wind-speed: 2-3mph.
  • Lifter: Jones Airfoils 8’Rokkaku.

it is a rokkaku design from the Japanese word meaning 'with six points'

Windspeed 09072015

380g, Filalu rig with auto control by clickPanPro, power is by 3.6V LiIon mobile ‘phone battery (NP BN1)  exposure control by Walter Wing: KAP UAV.lua CHDK script:


This was never going to be a directed camera shoot. I was amazed I manged to loft a camera at all: the kite needed nearly 300m of line to reach a stable flow at around 50m AGL and adding the camera almost killed the lift, the rig never rose much more than 20m and I got some gut churning surprises from thermals and decided to recover the camera after the big Rok topped me and looped …I had to spool huge amounts of line to keep control. I wasn’t expecting much…

Bridgemarsh Creek Ortho 1

15 frame orthophoto


About billboyheritagesurvey

Heritage worker
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7 Responses to Mudlark

  1. BKT says:

    Hi Bill,
    It’s a little off topic, but I see pictures of your wonderful yellow rok, I see the spine twisting in the wind. This image is an excellent illustration to the theory that such bending reduces the performance of the kite and acts as an air brake. I thought at 8′ it has a smaller effect, but you’re talking about wind speed of 2-3 m/s.


    • Piotr,
      The pic of the Rok was taken in a stiffer breeze at another time. In Bft2 the 8′ Rokkaku takes a lot of space and patience to raise, little by little I was able to catch the breeze with a huge lead of line over the camera. As the wind speed picks up the bending of the spine is a good thing, it’s all part of the energy absorption Roks are so good at, the spine is 3 piece Skyshark 8P with a tie point in the middle to keep the bow in the right direction.

      Your 10′ Rok is appealing…but I fear its survival if caught in a rising wind! The Jones 8′ will hold up in 12mph if it has to.

      I have noticed Roks change shape as they rise from face to wind (horizon) to zenith, the lateral flexibility they have through the bow and mid stiffened spars is remarkable: the tendency to ‘fold’ the dihedral is balanced by vertical deformation and the flex of the unsupported sail edges. It is a very stable design.

      • BKT says:

        My first sessions of 10 ‘is a constant nerves, what happens if you increase the strength of the wind? In the sea I had a few such situations, but some no major problems could cope. Only once I felt the power, but it was at the start and wind struck perpendicularly into sail. This my Rokkaku is relatively narrow, compared to the other 10 (Jims, Erich) and the more slippery on the surface wind resistance than puts him. Distortion sail during the flight are of strategic importance, it is the goal of my immediate playing with a kite. One more thing, this additional string in the bridle is in the normal position quite loose, tightens simultaneously with the increase in forces on the main lines.

  2. You are ‘exploring the 10foot envelope’…a tricky time indeed. A Bft 2 kite needs very lightweight spars…the extra bridle line is a great idea to spread the load on the spine. Have you used the elastic bridle to help the stress at all?

  3. BKT says:

    My brief experience with elastic bridle, the same as Hans, the problem with the start of a kite in low wind, and the continuous movement of the anchor point on the bridle. In the case of new idea, easy to start even without wind, and I think? easier to take down to earth with an average wind. wind force 2-3 m/sec, twine 1.2mm, no gloves, not KAP-men. There is something not as it should be 😉

  4. BKT says:

    I am still of the opinion that my new rokkaku, is a solution to my problems with weak drive. Now that I think about a little smaller version, it is fit better for European carbon tube size. This will reduce the sail surface to 5.2 sqm (5.6 sqm). With this bearing surface, you can hang rig near the kite, It almost does not change the behavior at this load (300-500g). It is also stable in the area of wind near the ground, which allows to play with 100 meters of cord on a spool. Returning to the ground, I still think that it is more easier. At the moment I have to sew two 10.5′ and unfortunately I have little free time, but I’m beginning to think about making panoramas. As my speeches sound like self-promotion, it’s very sorry, at last I have real joy of the evening trips :o)))

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