Originally Posted by bradleyjdonaldson
Actually there is NO FRICTION in a free spinning propeller on a turbine powered aircraft. There is no mechanical linkage between the propeller and the power turbine. If you watch a pre-flight on a turbo prop aircraft, you can free spin the prop like a windmill with no resistance what so ever. It is still detrimental to fully feather the prop as soon as you loose power to keep the dead windmilling engine from dragging the aircraft down. In fact if it is an air transport category aircraft it must have a AUTOFEATHER system to make the climb requirement after an engine failure on takeoff. ANYWAY..... Try this...Get a small prop from the toy store. Hold it out the window of your car while somebody else drives. Look at the difference in force aginst you with a spinning prop and a stopped one. You will be amazed how much drag a spinning prop makes!
well, not too sure how people will interpret this, had one of those toy pinwheels, stuck it out the window cruising into work, it spun happily along with a fair bend on the stick for a 1/4 mile or so, pulled it in and tied the blade so it wouldn't spin, stuck it back out the window, and the blades plastered back for a second or two, then the stick snapped off.
My view, stick was strong enough with the blade spinning, but not strong enough with the blade stopped, stick never changed, only the blade spinning or not, so I'd have to say drag increased when the blade stopped.
is a pinwheel identical to a prop? No, but many of the same 'laws' are in effect, and yes the entire surface area of a pinwheel is much greater than a prop.
had thought about sticking my trolling moter out the window and measuring the stress with a fishing scale, but figured that may raise questions.