Over a century ago M. A.
Batut's kite aerial photography apparatus involved a camera attached directly to the kite. By 1906 George Lawrence was suspending the camera from his kite line (cable) well below his train of kites. Separating the camera from the kite reduces camera motion and thus lessens blur in the image. By 1912 Pierre L.
Picavet was describing a cross-shaped suspension we now call the
Picavet. It involved a rigid cross suspended below the kite line with each of the cross' four ends connected to two attachments on the kite line. The line providing these connections is a continuous loop. Its attachment to the
kiteline and
Picavet cross sometimes involves pulleys. The result is a nominally self-leveling platform that resists a turning moment (as in the camera cradle rotating below it.)
This diagram of the
Picavet shows the systems major landmarks. The cross dimensions seem to vary from 20 inches across to as little as 3 inches. The loop of line that threads between the cross and the kite line attachment points is often 50 feet in length. A small split ring (R) is used to constrain the two innermost lines as they cross. Using the labels on the diagram as a key, a suggested threading sequence is
A1 - 1 - B1 - R - 4 - A2 - R - 2 - B2 - 3 - A1.
Through much of this century the
Picavet suspension was a lost idea and most
KAPers used a pendulum-based suspension (see Kite Aerial Photography by Mark
Cottrell, 1987). In 1988 the
Picavet method was rescued from obscurity by Michel
Dusariez in an article published by the Kite Aerial Photographers Worldwide Association (
KAPWA). More recently the
Picavet was described in an Aerial Eye article by Ralf
Beutnagel, Wolfgang
Bieck, and Otto
Bohnke (
Picavet - Past and Present, Aerial Eye, Vol. 1, No. 4, Fall 1995). The
Picavet is now a popular means for suspending camera cradles from the kite line.
(
http://arch.ced.berkeley.edu/kap/equip/picavet.html)
I was very fortunate to have a very talented Machinist working for me at the time that spend some off hours building my first and only
KAP cross. I used small, inexpensive hardware pulleys and as a first attempt and just hung the camera upside down off of a ball socket.
The attachment point (below) allowed a loop of line to pass where the nail is now and looped back onto the "T"
notch.
Here is the first look at my new camera rig built from Brooks Leffler KAP parts and James Gentles’ gent360-LED.
The LED trigger and servo runs off 4 NiMH rechargeable cells
The IR Led had a PIC built in so that every 10 seconds it triggers the camera and rotates the modified servo 60 deg. This is an older 3.2 Meg pixel camera I am using because of it's remote control capabilities.
I also bought a 12' wing span Delta which I lightened by replacing the semi-solid fiberglass spars with hollow fiberglass spars.
