DEFINITIONS AND ABBREVIATIONS

V.M.G.  Velocity Made Good.  Not your actual speed but the effective
speed at which you are proceeding in the desired direction.  For example; 
using sail or kite traction it is not possible to hold a course directly
into the eye of the wind.  A best course of about 45 degrees from true
wind is usually all that is attainable. If your speed holding a course 45
degrees to the true wind direction is, say 30 km/hr then V.M.G. to
windward is 30 km/hr sin 45 degrees or 21.2 km/hr.

T.W.  True Wind, the actual wind velocity and direction 

A.W.  Apparent Wind.  This is the air velocity and direction as it appears
to the operator and is the vector (don't panic!) sum of true wind (speed
and direction) and the buggy/kite boat velocity and direction.  For the
kite the apparent wind is the vector sum of the true wind (speed and
direction) and the kite's velocity and direction.

Reaching  Sailing on a course approximately at right angles to the true
wind direction - usually the fastest point of sailing.

Stall/fly  A kite characteristic in which the kite stalls often hovering
or even falling backwards, needing to be "pumped" to get it started again. 
Usually caused by having the bridle too far back.  Kites stall/fly is
usually an undesirable characteristic, interfering with smooth flying,
but for kitesailing and buggying it can be advantageous as it can allow
the kite to be de-powered even while in the centre of its power band
providing the true wind speed is under say 25 km/hr and can in some other
cases improve light wind upwind performance.

L.D.R.  Lift to Drag Ratio.  The ratio of lift force generated by the kite
to the aerodynamic drag forces operating on the kite and line.  (The
downwind component of all the aerodynamic forces acting on the kite/line
system.)  A quick method of measuring kite L.D.R. is., for the situation
apparent wind = true wind, to park the kite overhead in steady state and
determine the tangent of the angle between the flying line and the
horizontal plane.  This is exact.

M.M.R.  Minimum Pull to Maximum pull Ratio.  For given true wind, the
maximum pull that can be generated by the kite while being flown by a
static (feet on the ground) flier.  (This maximum pull will usually occur
when the kite is climbing at maximum velocity and is directly downwind
from the flier) is divided by the pull generated by the same kite in the
same true wind  when the kite is parked up at the top or at the edge.

At the Edge  A semi circular arc in the vertical plane, centred downwind
from the flier which represents the furthest upwind positions that a
kite can maintain in steady state flight for given wind velocity.

C.P. Luffing  Centre of Pressure Migration Luffing.  Occurs when the
point at which the lift forces act migrates sufficiently to the trailing
edge to tilt the kite down (negative angle of attack) into the wind
causing the leading edge to fold under, collapsing the kite.

A.W. Luffing  Apparent Wind Luffing occurs when the kite suddenly flies
into a zone where the apparent wind direction is such as to create
negative angle of attack, causing the lines to go slack and the kite
canopy to collapse.

Angle of Attack  Angle of the apparent wind relative to the (nominal)
lower surface of the kite.  This angle is positive when the apparent wind
strikes upwards onto the kite's lower surface.

Aspect Ratio  Roughly, the ratio of wing span to chord (wing width) but
more precisely span2/area.