[EricH]

Originally Posted by engunneer

There's a theory that I give to students in the machine shop. Whenever something is moving, look for the "plane of destruction". It's the plane where things go flying when (not if) things go bad. You never want to be in the plane of destruction.

My Aero Design team has a rule: NEVER stand in the same plane as the prop while the engine is a) running or b) about to be started. In front or behind is OK (or required, depending on who you are), but never to the side. Shield the plane of the props, and a little in front of and behind that plane, and you *should* pass inspection. By doing so, you also get a "ducted fan", where there is almost a funnel for air to pass through. These are just as good as unshielded props, if not better.