Notes on Kite Aerial Photography: Equipment
A RIG using a DISPOSABLE CAMERA
So Dad what are we going to build for the science fair? Ah yes, another Science Fair. Thomas decided to build a Kite Aerial Photography rig after mulling over ideas for home-built laser weapons (his) and air flow visualization (mine). For this to be his project we decided it would be built around a disposable camera and a dethermalizing timer purchased earlier. We also accepted as a challenge of sorts that we produce the rig using only materials available in our workshop (other than camera and timer.) So for a week or so we spent evenings in the workshop and produced the device shown in this section. It should take an adult only a few hours to make a similar rig.
We used a dethermalizing timer, common in the model airplane community, built around a spring-wound clockwork and settable for periods ranging from 15 seconds up to 6 minutes. A slotted disk is rotated by the clockwork to finally free a small wire when the timer has expired (position shown). The then-loose wire can cause an event (camera exposure) to occur through a mechanical linkage or electrical switch closure. The timer is nicely-made and runs around $30. Timers can be found at hobby stores specializing in model airplanes. I've also had good luck with mail order from Stanton's Hobby near Chicago.
We built Thomas' rig largely out of wood and aluminum.
Working from the top down: a wood cross supports a bent 1/8" aluminum bracket (too
thick but this is what we had) via a bolt and wingnut.. The direction the camera faces is
set here. The bracket holds a lower bracket made of 1/16" aluminum and this in turn
supports the camera, a disposable Fuji. The lower bracket is u-shaped and connects to the
upper bracket with a nylon bolt, washers, and a wing nut. The camera's downward view is
set here. On the opposite side of the u-bracket from the bolt connection is the timer,
mounted on a basswood plate. The timer's wire, when captive, restrains a wood dowel lever
that is positioned above the camera's shutter release. The lever, pivoting on coat hanger
wire, is drawn toward the shutter release with a #64 rubber band (shown out of position in
photo.) The camera is secured to the bracket with #54 rubber bands shortened a bit with
Rig based on a disposable camera,
September 1995 (36K jpg)
The image below shows Thomas' rig in flight and me apparently taking a bow. The rig is supported by my Sutton Flowform 16 just a few moments into its maiden flight. The suspension is a Picavet rig made from wood bars about 12 inches long, half-lapped in the middle and sporting eye screws at the end. The four ends of the Picavet cross are connected to the kiteline about 100 feet below the kite with about 40 feet of line threaded back and forth between two loops (Prussic knot) on the kiteline and the four eye screws.
as seen from below,
September 1995 (19K jpg)
This image shows Thomas' rig in flight looking down toward Thomas and myself. Taking photographs with the setup if straightforward. You set the camera's direction (bolt connecting with cross and rig) and tilt (bolt connecting brackets). Then lift the shutter trigger (wood dowel), engage the timer by spinning its disk above the captured release wire, cock the camera's shutter, and send the kite upward. Fly the kite to lift the camera rig to the desired height and wait for the time interval to expire. You can often hear the click of the shutter as it releases. Six minutes is a long time. Most of our exposures were taken with the timer set for three minutes and even this seems long.
of the rig in flight taken with a second camera cradle mounted on the same kiteline,
September 1995 (52K jpg)
The rig performed much as expected and we took 27 images the first day out. You might recognize the Berkeley Waterfront, our kite 'proving ground', in the images. The disposable camera's shutter seemed sufficiently fast to avoid most blur. The lens is sharp enough to produce recognizable results but doesn't put your better cameras to shame. It is kind of fun flying with an uncomplicated rig that puts very little equipment in harm's way.
buggy paths at the Berkeley Waterfront,
September 1995 (39K jpg)
portrait (as ants),
September 1995 (42K jpg)
An Idea Under Development
Somewhere a couple of months ago I saw mention of using a kite messenger to send a camera skyward (Mouton's book?, I could use help here). A messenger is a craft made to travel up the kiteline under sail power and, on reaching a predesignated point, to detune the sail and return to the ground. They are often used to lift and drop parachutes bearing candy or stuffed bears (fauna). I'm interested in developing a messenger to lift a camera up the line, trigger its shutter, and return it for winding and relaunching. So far I've made a messenger and played around with parachutes and balsa gliders - much fun. Some day (next science fair?) I'll get back to work on it.
messenger made of aluminum tube, basswood, and model airplane covering (Monokote),
September 1995 (18K jpg)
Another view, September 1995 (53K jpg)
To my great delight NASA has posted a page describing a low-cost KAP Project.
Hobbyist Gary Vigue posted a diagram of another low-cost rig to the KAP Discussion Group.
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