The High-side Attack
In any attack, the rate of turn which an attacker needs to track a target may be expressed as radial G, and can be shown by the following formula:
N = Vf x Vt x Sinθ / 32.2S
The radial G expressed here represents the lateral acceleration of the fighter in the horizontal plane. It does not represent the total G on the aircraft, since it neglects the pull of gravity (1G). Total G is the resultant of radial G and 1G pull of gravity acting through the vertical axis of the aircraft. This total G determines angle of attack – the angle between the mean chord line and the relative wind. Since total G determines angle of attack, the aircraft stalls on total G. In view of this fact, and because our previous formula considered only radial G, we must determine the exact relationship between total and radial G. It may be expressed as follows:
Gt² = Gr² + 1
Where
Gt = Total G
Gr = Radial G
1 = 1 G gravity
We can see, by the formula, that total G will always be greater than radial G. This is a disadvantage, because the rate of turn which an attacker needs to track a target, or the range to which an attacker can approach a target is dependent upon radial G, not total G. This disadvantage becomes less at higher G values because the difference between total and radial G is less. Example:
If Gt = 4
Gr = √(Gt - 1) = √(16 - 1) = 3.87
If Gt = 1Gr = √(Gt - 1) = √(4 - 1) = 1.73
The difference between 2 and 1.73 = .27 whereas the difference between 4 and 3.87 = .13
Since a greater difference exist between Gt and Gr at lower G values, the rate of turn is reduced not only because less total G is available, but also because an even greater loss of radial G is experienced.