As with all Control Line aircraft, control is achieved by the two lines controlling the elevator(s), and sometimes with flaps on the wing acting in unison but opposed to the elevator. This Control Line discipline calls for absolute precision of that control.
Control Line AEROBATICS (often referred to as STUNT) is the competition performance of a sequence of specific manoeuvres, referred to as “The Pattern”. The Rules are very specific in describing exactly what the manoeuvre’s shape should be, how it should be flown, and the sequence.
The Pattern is different for each of the three disciplines, but consist of basic Loops – round, square, and triangular; Figure Eights – round and square; and a Four-Leaf Clover. These are observed by Judges who award marks according to how close the manoeuvre has been flown as per it’s description in the Rules.
The Starting of the engine (time factor); Take-off; Landing; and elapsed time (limit) are also subject to the Judge’s scoring. Speed or laps-flown competitions are accurately measured. Aerobatics is totally subjective. What one person “sees” is often significantly different to another, which then leads to heated debate about “good”, “average”, and “poor” manoeuvre shapes.
Added to that, the Pattern describes manoeuvres as the Pilot sees them from the centre – the Judges see them from the perimeter of the flight circle – the base of the flight hemisphere.
If this sounds relatively easy, it most certainly is not! Consider the model heading vertically down toward the ground at a speed of between 80 and 120 KPH, and turning into either upright or inverted horizontal flight at a height of 1.5 metres, and with a turn radius of less than 2 metres.