11-28-2013, 03:08 PM
Allow me to say an "uh, not really" right back at ya.
I am a pilot and understand all about "ground effect" but that's not quite the same thing. Thrust, whether it is from a propeller or a rocket, comes from the velocity of the moving stream. It's an action/reaction thing, so for a given mass of moved material, as its velocity increases, the thrust increases at the square of the difference. If the mass encounters anything, it slows down. So "pushing against" something lowers thrust.
Rockets work better in the vacuum of space because there's nothing to "push against" thereby slowing it down; the ejected mass has more velocity.
But all this is academic. Try your project with and without a "floor" and see. I know that in my Hobie, working the fins in flutter mode near the kayak floor give less thrust than when the fins are away from the floor.
[signature]
I am a pilot and understand all about "ground effect" but that's not quite the same thing. Thrust, whether it is from a propeller or a rocket, comes from the velocity of the moving stream. It's an action/reaction thing, so for a given mass of moved material, as its velocity increases, the thrust increases at the square of the difference. If the mass encounters anything, it slows down. So "pushing against" something lowers thrust.
Rockets work better in the vacuum of space because there's nothing to "push against" thereby slowing it down; the ejected mass has more velocity.
But all this is academic. Try your project with and without a "floor" and see. I know that in my Hobie, working the fins in flutter mode near the kayak floor give less thrust than when the fins are away from the floor.
[signature]