first off
Won't that spam errors every time it explodes
no
I took a look at the source code and the variable will default to something else if you do this
you haven't quite explained what you want very well so I'm just going to assume
the easiest solution that doesnt require you to rewrite vehicle functions would be to just create a projectile that does nothing like so
datablock projectileData(emptyProjectile)
{
lifeTime = 0;
};
then set whatever variable you want to this emptyProjectile and it will create this projectile momentarily (which has no model or explosion)
this is the simplest solution that will work in mostly every circumstance
Edit:
Special thanks to "thegoodperry" for coming up with this idea first