Sorry Paphitis! I just logged on again because I am not really a very regular attender of such forums (not good for my health) - they are only exciting if taken in small portions
You asked too many question and I shall explain to you the load factors on this occasion as shortly as possible. First you must familiarise yourself with some of the terminology.
Mass (m) is the amount of matter in a substance and it does not change in value no matter where you are in the universe.
Weight is the vertical force exerted on a body due to earth’s gravity (or the gravity of the planet you are on). It is given as:
mg = mass x acceleration (due to gravity - downwards).
Lift (L) is the force on the body and wings of an aircraft, opposing the downwards “weight” (W) force. When in level flight lift force must equal to the weight. Since the mass is same for both the weight and the lift on the aircraft, the lift force acceleration upwards must also be equal and opposite to the gravitational (g) acceleration downwards.
The Load Factor (G) also known as G force, is the ratio of the lift force to weight, given by the formula G = L / W
Any increase in the speed of an aircraft also increases the lift force due to aircraft’s aeronautic wing and body design.
A steep turn is any angle of turn higher than 30 degrees.
When you enter a steep turn, the wings are at an angle to the ground. The weight (W) stays the same because it is always vertically down, The lift force however, acts on the wings (at right angles to wing surface). If you visualise an aircraft in a turn with the weight force vertically down and the lift on wings at right angles to the wing surface, you can see that the two forces will no longer be opposite. Only the vertical component of the Lift force will counter the Weight. This component is only a fraction of the actual force acting perpendicular to the wing surface, hence the speed of the aircraft must be increased to increase total lift where the vertical component can compensate for the weight.
When the speed and hence the lift increases, the acceleration in a turn also increases and this will clearly be more than the gravitational (g). It is this acceleration towards the centre of the circle of the turn that pushes you in your seat and you feel a pressure on your backside (as well as internal organs).
During straight and level, the since lift (L) and weight (W) are equal (and opposite); G = L/W = 1
In steep turns, depending on the angle of the turn, the lift will need to be higher, at an increasing rate to compensate for the weight and prevent a stall. This is achieved by increasing the power and hence the speed of the aircraft. The bigger the angle of turn the more power and speed is required to counter balance the weight. NOTE: This is same as saying “the stall speed will be higher at greater angles of turn” (ie the aircraft will stall at a higher speed than it would have done during straight and level flight).
The standard load factors (G) for different angles of turn are given by:
0 bank G = 1
30 bank G = 1.15
45 bank G = 1.4
60 bank G = 2.0
75 bank G = 4.0
Based on above information you can work out the safe speed for the turn by calculating the new increased stall speed (Vsa) using the normal stall speed value (Vs) and the Load Factor (N). The formula for working that out is:
Vsa = Vs x √N If your normal stall speed (Vs) is 40 knots then the above values will tell you that:
0 degrees bank G = 1 Vs = 40 knots
30 " bank G = 1.15 Vsa = 40 x √1.15 = 43 knots
45 " bank G = 1.4 Vsa = 40 x √1.4 = 47 knots
60 " bank G = 2.0 Vsa = 40 x √2.0 = 57 knots
75 " bank G = 4.0 Vsa = 40 x √4.0 = 80 knots
Usually extra power is also required to oppose the increased drag at those angles. But usually an increase of 100-200 rpm would do for a 45 degree bank.
IMPORTANT: You must remember that the aircraft’s speed in a turn should be at least 10 knots above the stall speeds worked out above.
