Also , doing run ups on a gravel or loose surface , can give you a chipped and damaged prop , and of its not you r aircraft , you might get a tounge lashing , or worse , a bill for repair .
Its good practice to start the take off roll and do a quick mag check ,
The jaby engine doesnt have mags as such , so you are only doing a " function " test of the coils .
Quickly . Left on / off , right on/ off ,
You dont need a long drawn out test ( cesnas ect)
On the jab engine , long " mag " checks only serve to fowl plugs , and if done while stationary , will create a small tornado on the ground in fromt of the prop and suck up stones and such .
Mike