Gary, you can somewhat achieve this same effect for a artillery shell hitting in the ground. Grab a small funnel, hook up some nitro fuel line to the small end and add talc the open end (wont need much), cover loosely with saran wrap or foil. Bury the funnel just to cover the up end (saran wrapped) and attach the other end of the fuel line with some compressed air. Voila, smoke and dirt go a flying. Only conern with this is getting all that junk in your IR tube and apple if your battling and some goof decides to set it off while your tank is literally right next to it. Could make for a nice effect on one of your next videos. Here's the funnel size you'd be looking at. Maybe you'd have something like it at work but it's kinda small.

http://store.rc4wd.com/Hydraulic-Oil-Funnel_p_2973.html