Why KAP?

A poster on using a microcopter for low level aerial photography of heritage sites at CHNT17 caught my eye. The proposition was straightforward and the images to support it looked good: using a video camera sweep it is possible to clip out frames to use as stills and model from them the captured terrain. I noticed there was a lack of classical nadir coverage in the examples shown and on further investigation found the camera was on a fixed mount requiring the miocrocopter to fly on its rotor edges for nadir cover!
Micrcopters are getting better all the time and I’m sure are better than kites in many ways, being able to fly the camera where you want is a very attractive prospect! So far the flight durations are short and the unit costs high, there are some really good mapping project results to be seen too…but for me flying a kite is a joy I’m reluctant to give up.
Here is a summary of the options as they look today: provided you have patience and a love of kites they are still a very cost effective platform…even if you can’t always put the camera where you want to!
Low Elevation Aerial Photography (LEAP) options
Approximate Cost‡
Unmanned Aerial Vehicles:
‘Hobbyist’ Multi rotor semi autonomous RC helicopter*
Rapid, stable, camera positioning. Up to 1kg payload. Predictable photocover.
11mins flight time per battery


‘Professional’ Fixed wing ‘drone’ or  autonomous RC aircraft
Programmable flight path for stereo swath cover.
High altitude (600m+), high flying speed. CAA certification status ‘unresolved’ at present.


‘Hobbyist’ Manual RC helicopter*
Rapid camera positioning
11mins flight time per battery.
High pilot skill level


‘Hobbyist’ Manual RC ‘plane/Glider*
Rapid camera positioning
20-30 mins flight duration
High flying speed and therefore height above 300m required for sharp images. High pilot skill level
RC fan assisted dirigible balloon
Indoor flights possible.
20-30 mins flight duration
Cannot operate in windy conditions. Cost of helium
Un-powered tethered lifers:
Flight duration Stable no- wind
Limited to 60 m cost of Helium per flight. Cannot operate in windy conditions Clear line zone handling required.
In practice a selection of 3 or 4 kites is needed to meet wind conditions between Bft 2 and  Bft 4
Flight duration: all day if weather permits.
Limited to 60 m. Clear down wind line zone required. Weather dependent.
Camera position limited to down- wind path.


HeliKite/ kitetoon
A hybrid design of kite stabilised balloon
Flight duration: all day if weather permits. Zero wind capacity
Limited to 60 m.
Clear line zone handling required. Cost of Helium per flight.
*Professional (or exceeding 7kg in weight) requires CAA certification.
†includes cost per filling of 3m3 helium.
‡excluding cost of 1kg camera payload with video relay.

There are unresolved legal issues on the civil use of autonomous UAVs and certification by the CAA is a necessary constraint given the airspace available to the ‘copter flyer but the results are improving as battery technology marches forward


About billboyheritagesurvey

Heritage worker
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5 Responses to Why KAP?

  1. Jasja Dekker says:

    Nice post. I am not giving up KAP either but DID buy a fixed wing model airplane with autopilot, gps, etc. Curious how effective it will be.

    • Thanks Jasja,
      I’d love to see some results from your RC plane: it’s a great view up there!
      Personally I don’t think the unique sense of achievement from KAP is possible when using an autonomous drone. Free flght with an RC plane/helicopter would be thrilling but I enjoy the balance of wind and light that the kite brings to landscape photography, KAP means you have to get to know the setting and from this the photography grows….it’s a new learning experience with each flight!

      Yesterday I spent 2 hours getting this: http://www.flickr.com/photos/bblakecambridge/8186206044/ and it’s not even close to what I wanted. I was able to practice slack line technique with the rokkaku and learn the wind and light conditions I’ll need to to get my shot. With a microcopter I could have got my shot and been home in minutes but would I experience the satisfaction of knowing I’d worked with the wind?
      Or is it a case of willfully doing things the hard way for the fun of it?


  2. Tom Benedict says:

    Like Jasja, I’m also getting a plane. No GPS, no auto-pilot, just an RC airplane and a radio. I don’t really see it as a replacement for KAP. Like you said, the experience is completely different. I expect I’ll continue to enjoy flying kites and doing KAP. And on windless days I’ll enjoy flying the airplane. I might stick a camera on it to do movies, but except for relatively high altitude flights I doubt I’d use it for stills. It’s not so much a replacement as it is another way to enjoy the day when the conditions aren’t right for a kite.

    But I do see a way in which the two could play together nicely. (Keep in mind I’ve only participated in one aerial survey for archaeology, so if I’m off-base feel free to laugh, pat me on the head, and say, “There there… I’m sure you’ll learn.”) It seems like there would be utility in flying both a KAP rig and an RC airplane rig at the same time. The RC airplane could capture high altitude relatively low resolution data quickly, and could block out a large 3D model of the extended site. At the same time one or more KAP rigs could be used to get lower altitude, higher resolution data sets for areas of interest inside the larger model. The real trick would be coordinating the two approaches so the data would mesh, and to keep the airplane from hitting the kites.

    • Thanks for the comment Tom.
      So far apart from the big guns ( http://www.gatewing.com/ for example) the swath control needed for good photo-cover from an RC plane has proved to be harder than you’d imagine. I certainly think its worth a go though. The problem is that speed of the plane pushes the altitude pretty high to avoid forward motion blur.

      The RC plane is probably more practical than a balloon on windless days (no helium costs) but I find the pilot skill level a bit beyond me!

      The idea of capturing imagery as a variety of resolutions is sound: you are spot on there Tom!

  3. Jasja Dekker says:

    I agree, the plane is a nice new tool in my toolbox, I sometimes use PAP but what I love most is the kite photography. Planning, finding the right wind/kite combo. And it seems to appeal to people commissioning photos too.
    And although I sometimes do wonder why I just do’n’t get a copter that I can fly to the right point, take the shot and go home, having spoken to some professional filmers that hired octocopters for footage, they are not quite ideal: much wind gives problems, short battery life means having to swap andspeedcharging them from a car battery in the field, crashes and field repairs… etc.

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