Quote Originally Posted by Slon
The onager took out part of my phalanx that was near it. .
If you place all of your onagers in a line directly behind you line infantry all of you troops will be well within minimum range.... you'll notice that enemy troops will become too close to shoot at just before the close on your ranks.

The only possible mishap you can have is when you have a row of onagers and you target all of your onagers at something to the extrem right or left of the line. Since the onagers have a large profile (i.e. they are high) the onagers are easily capable of shooting each other "in the back". I would suspect that if your troops were genuinly within the minimum range, the only possibility was either a deflection from one onager hitting another, or they were far enough in front of the onager to get hit by a truly wild shot. The added advantage of keeping the distance between your onager line and your infantry line small is that the onager ammo leaves the onager at a certain distance above the ground. The closer the two are together, the more impossible it becomes for even the wildest shot to hit anything friendly since it starts some distance above the heads of the infantry (sorry, too tired to explain the geometry).

Set up a custom battle and play around with them. At best you'll be converted, at worst you'll have a nice firework display.