APC Prop differences
08-15-2007, 11:12 AM
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RE: APC Prop differences
The slow-fly props have a much wider/fatter blade and are designed to produce higher thrust, at lower rpm and throttle settings. They are generally used for low power operations and 3D flight. They are not really designed for the big power setups.
08-16-2007, 01:55 PM
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RE: APC Prop differences
APC E are rated at 190,000rpm/diameter (a 10" E prop would be safe at 19,000rpm).
APC SF are rated at only 65,000rpm/diameter (so you should not use a 10" SF prop at any more than 6500rpm)
APC SF are rated at only 65,000rpm/diameter (so you should not use a 10" SF prop at any more than 6500rpm)
08-16-2007, 07:52 PM
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RE: APC Prop differences
Something I only learned recently. Props actually use two forces to move the plane. The first is newton's law - I push something out the back (air) and to conserve momentum the plane moves forward. The second force is the bernoulli affect on the prop - the prop is actually a little wing biting the air. Like all wings, it has an optimal angle of attack with an air stream at which it produces the most lift (and in this case lift drags the plane forward), or is most efficient. At different speeds the angle of attack against the propellers blade changes due to the component of velocity moving forwards. This means that by varying the angle of attack of the propeller you can vary the most efficient air speed for the propeller.
I think others have said similar, but my guess is that slow flyers are optimized for a lower airspeed.
I think others have said similar, but my guess is that slow flyers are optimized for a lower airspeed.
08-18-2007, 11:57 AM
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RE: APC Prop differences
I've used APC SF props on what would be considered higher k/v motors. Some times they perform better than the E versions. For instance, a 2408-21 (BP21) runs really nice on a 7x6SF on a Stryker, better than any E I've played with for best combination of speed/torque. I recently tried that size on a 2409-12 on the Stryker and it seemed as faster (probably faster) than the 8x6E I was using, with lower amp draw. It for sure made the motor run smoother. The only risk is SF is not meant for very high RPMs. Be VERY careful and act like it could explode at any time until you've got gobs of flight time on it to be sure.
