Aerodynamics

Question 1

Centre of Pressure

Answer 1

the point where the aerodynamic forces act after adding them up (towards tip of bullet)

Question 2

centre of mass/ centre of gravity

Answer 2

where the bullet balances its weight

Question 3

what is the angle of attack

Answer 3

the angle between the longitudinal axis and the trajectory

Question 4

why do you add spin to a bullet

Answer 4

for gyroscopic stability

Question 5

what is drag coefficient

Answer 5

Fd = 1/2 Cd A V2 rho

Question 6

Ballistic coefficient

Answer 6

Cb = Cg / Cd x m/ d2

Question 7

1kg = ? grains

Answer 7

15400

Question 8

Spin rate

Answer 8

Muzzle velocity / twist rate

Question 9

green hill formula

Answer 9

T= (C x d2) / L
for muzzle velocities under 860 m/s then C = 150
for muzzle velocities over 860 m/s then C = 180