Originally Posted by
Homsap
BEagle...... Are you able to let us know why military circuits are a racetrack pattern, just wondered what the historical basis was?
I'd put it the other way around - why do civilians fly square circuits?
A circuit is surely intended to bundle a number of exercises (take off, climb, turn, level, speed changes, approach judgement and landing) in the vicinity of the airfield and as the engines of the early days were less than reliable one should never be out of gliding range of the field when in the circuit. That requirement, though often ignored today surely remains an important aspect of circuit flying.
The downwind leg ended with what is effectively a PFL - power off and adjusted with blips of engine (rotary). We now extend that a little to allow power assisted finals but the attitude judgement in that constant turn still replicates a PFL, good practice.
Square curcuits inevitably push the circuit too wide by the need to insert wings level sections on crosswind and base and you lose the safety of being in gliding range of the field and the all-important attitude judgement of adjusting your turn to achieve whatever gate is set for the finals point.
I can't see why civvies do these vast square circuits getting 6 - 8 circuits per hour instead of a dozen. Returning to racetrack circuits would solve the cross-country circuit syndrome at a stroke.