Explosion deaths for Oinkerwinkle?

Explosion deaths for Oinkerwinkle?

I using oinkerwinkle and i want to make a projectile that explodes once it hits the ground.
How i do this?

There are projectiles in game, that explodes on the ground , like mortar team projectile ,the orc catapult and so one .. its more simple to edit the existing projectiles then to create new ones