Weapons Delivery Principles and Procedures
FACTORS AFFECTING TRAJECTORY
It would be great if we could come down the chute every time on a no-wind day and pickle exactly on
airspeed and altitude with no yaw and the pipper right on the target. However, a change in any of these
parameters will affect the trajectory of the weapon. The effect of changing each parameter will now be
Releasing high will increase the time of fall of the weapon, and so will increase the time during which
gravity can act to bend its trajectory. You are also releasing a greater distance from the target. There-
fore, if you release high, with all other parameters correct, the weapon will hit short. Similarly, if you
release low, the hit will be long.
Any deviation from planned release airspeed will cause a false sight picture. For example, a fast release
will decrease your AOA and bring the pipper short of the impact point causing a long hit. A slow release
will show the pipper long and cause a short hit. Airspeed also has an effect on the weapon's time of fall.
Deviations from planned dive angle will also cause a false sight picture. A steep dive will cause a long hit
and a shallow dive a short one. Changing the dive angle will change the extent to which gravity will bend
the weapon's trajectory below the line of flight. Suppose you release a weapon at a dive angle of 90
degrees. Since gravity works straight down, there will be no effect on the trajectory. You can see that a
steeper angle requires a smaller mil setting; if you release steep, your mil setting is too large and the
bomb will strike beyond the target. If you are shallow, you need a greater mil setting, just as you do for a
shallow pattern, and your hit will be short.
G at Release
Proper g at release depends on dive angle. For a 30-degree delivery, about 0.87 g is required to main-
tain a straight flight path. A 10-degree dive requires almost 1 g. A 60-degree dive (not used in the
training command) would require only 0.5 g. The mil setting for each type of delivery is valid only at the
proper g. Incorrect g at release will change the angle of attack of the ADL and will invalidate your mil
setting by causing a false sight picture. Excessive g will cause an early sight picture. So, if you apply
excessive g to obtain the proper sight picture and have all other parameters correct, your hit will be short.
Insufficient g will cause a long hit. In addition, incorrect g will have another undesirable effect--changing
your dive angle. Proper g results in a straight flight path and a constant dive angle. Too much g will
shallow the dive angle, and insufficient g will steepen it.
Because of the depression of the sight line below the line of flight, any bank will cause a false sight
picture. This error is caused by the pendulum effect (Figure 17), so that if you roll to the right, your
pipper will appear to move to the left along the ground. Thus, if you release with the pipper on target
while you are in a right bank, your hit will be to the right and short.
A skid or sideslip can also affect the trajectory of the weapon by causing a false sight picture. Unless the
ball is centered (balanced flight), the aircraft will not be moving in the direction the pipper is looking. So,