This is a simple winder for KAP. KAP generally uses strong single-string kites as lifters: you get the kite and the camera up there, and you don't do a lot with it once it's there. Meanwhile, you want to be working your controls to take photos.
This is a design that I've seen around on the internet for a while. I'm sure the resemblance to a Klingon bat'leth is entirely coincidental.
Step 1: General dimensions
You'll need a piece of wood about 26" by 7". A lifting kite can put plenty of force on you, so choose something thick and strong - a floorboard or a bit of sturdy plywood is ideal. I've got MDF, because that's what was handy.
Step 2: Make a template
Use a folded piece of paper so that both sides are symmetrical. The hand-holds are 1.5" by 5" (a bit large to allow easy use while wearing gloves). I got the position of the angled hand-holds by cutting a little hand-hold sized scrap of paper and moving it around until it looked right.
Step 3: Cut out the blank
Cut it out. I used a big hole-cutting drill bit and a jigsaw; use whatever you've got handy. Remember, when working with MDF, to wear a mask. It's nasty stuff.
Step 4: Smooth up and add the furniture
Sand it all down nice and smooth. You can seal it with varnish now - I haven't because I'm cheap :)
Put a notch in the centre of the beam to anchor the kite string.
Drill a pair of holes between the hand-holds. To one, attach a little carabiner so you can lock the kite line: when it's flying, pass the line through this crab to stop any more line paying out.
To the other, attach a loop and a big climbing carabiner. This will let you clip the whole thing to a belt or harness leaving your hands free to work the radio controls. CAUTION! If you've got a strong kite, you're light, or it's gusty, TAKE CARE because lifting kites can be brutes and being thrown around by one is a painful and expensive affair.