ABSTRACT

Now that the basics of the terminology and the dynamic equations have been presented, we shall begin to look at their uses in the form of prediction of trajectories. The aeroballistician is usually faced with one of two problems: ‘‘If I want to hit a target at position x, to what elevation (and perhaps with how much propelling charge) do I have to elevate the weapon?’’ or ‘‘Myweapon is elevated to elevation x and I expect muzzle velocity y-where is the projectile going to end up?’’ To approach this in a logical and easily understandable fashion, we shall begin with a

great many simplifying assumptions, relieving these as we progress. Each section builds upon the previous one so that we recommend even seasoned veterans progress in numerical order. Initially, we will only look at the effect that gravity imposes on the projectile, a vacuum

trajectory, so that even the air is removed from out area of concern thus neutralizing the fluid mechanics for a while. As we progress, we shall add in the atmosphere but neglect dynamics, atmospheric perturbations, and earth rotation. One by one we shall continually step up the complexity until finally we shall introduce the full six degree-of-freedom (6 DOF) equations. Onemight initially think that these simplifiedmodels have no practical use, but aremerely

educational stepping stones. Nothing could be further from the truth. In many instances, some of the complications only slightly affect the solution and a ballistician is well placed to assume them away. Some of these common situations will be pointed out as they arise.