differences and problems arise when it comes to attaching the camera and the 
various accessories to the kite. It is rather difficult to find a suitable 
position on a structure as light, as sensitive and as plane as a kite. 
The system used for the experiments and which will be later assessed for 
its photogrammetric feasibility consists of the Dunford Flying Machine 2000 
(DFM 2000), together with a secondary delta-shaped kite (Cochrane, 1980). The 
system is completed by the camera, a Canon AE-1 and a two unit radio control. 
The main lifting power is provided by the DFM 2000 (Fig. 1). It is rhomboidal 
in shape, building & dihedral angle in space and has & span of 2 m. The cambered 
wings give & good lift, ensuring that the angle of incidence of the wind on the 
main wings is different at the front and rear of the kite. The same applies for 
the angle of incidence of the nose of the main body and that of the tail. These 
combined factors ensure precise pitch (phi rotation) control and increase the 
flying stability. The dihedral angles at nose and tail ensure lateral stability 
and provide a good lift component when the kite is flying on its side. The shape 
of the kite causes a split air flow. This feature ensures that, no matter what 
the kite's attitude, the air flow over the tail of the kite is unaffected by any 
turbulance generated by the nose of the kite. The tail can therefore act as a 
weathervane, thus providing precise control in yaw (kappa rotation). The porosity 
of the specially made nylon fabric allows a suitable amount of air to flow through 
the lifting area in order to minimise vibrations while in flight. 
Two further important features are, firstly, the aperture in the fabric in 
the centre of the kite, which enables the DFM 2000 to act like a parachute when 
temporarily or permanently released from operator control, or when the wind drops 
and there is absolute calm. Thus it may float downwards, if required, at a speed 
of approximately 600 mm sj a fact which guarantees smooth landing. Secondly, the 
fabric is stretched over a three dimensional structure consisting of a main(central) 
plastic tube to which are attached the wooden spine strut, the wooden control bar, 
the front strut and also the two metal rods on which the cambered wings are secured 
(Fig. 1). Further tensions are gently applied by cotton thread rigging. It is this 
structure that provides a base for attaching the camera and any additional equip- 
ment. The flying attitude of the kite (mainly omega rotation) may be controlled 
by trimming. This is carried out by sliding the central vertical strut forwards 
or backwards along the spine strut. The rigging should, of course, be adjusted 
accordingly. This trimming is in effect a displacement of the centre of gravity 
which changes the flying attitude of the kite and hence the angle of incidence of 
the wind. It becomes quite critical when the weight of the camera is attached to 
the kite. It should be noted that, in this way, the DFM 2000 is not bridled, but 
is free to rotate around the control bar. As a result of these features, the kite 
will adjust to a stable position for almost any given wind condition and will auto- 
matically revert to that position after any wind gust or aerobatic manoeuvre. 
The system is completed by the Delta kite. This is a delta-shaped,twin keeled 
plane kite which, when its line is attached at the back of the central strut of 
the DFM 2000, provides extra lift by exploiting the generally windier, higher 
atmospheric strata. Its use is advantageous in the case of low wind speed on the 
ground. Steering the two kites in tandem, naturally becomes a more difficult task. 
However, the use of the Delta increases the stability of the camera platform. 
The camera with the power winder is attached to a simple and light tripod 
head which, in turn, is bolted on the central strut. Thus the camera position 
is fixed. If required, the axis could be made vertical, or nearly vertical, by 
inclining the tripod head according to the flying attitude of the kite. A two 
unit proportional radio control is used to trigger the shutter. The receiver, a 
set of four batteries (1.5 V) and the servo mechanism with the attached cable 
release are mounted on a light aluminium base plate, which is clamped around the 
central strut. 
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