I am documenting my progress as I journey through this crazy life of radio controlled planes. If you have questions or comments, please write them below. I am documenting my frustrations and discoveries along the way, and pointing out what I watched and read so that you too have sources.
Today I am leaning about propellers. So, here's a question. As a joke I decided to seriously upgrade the motor of your office fan, by 50 times. The thing goes flying, does it hit you or fly away from you? You're getting the windblast but the fan will fly away from you and probably hit the wall and break into many pieces and I'll have to pay for it, sorry.
Another question, I know you've watched the fan spin its blades around many times before. When you turn it off you watched it spin down, what direction was it going, clock wise, or counter clockwise? With the fan blades pointed to you to keep you cool it was going clockwise.
These are the things to keep in mind about propellers. An airplane like a Cessna has a large propeller on the front of the plane. It pulls you though the sky. So, these propellers pull you in a counter clockwise rotation. This is the most common. The planes I am interested in have propellers in the back that push you through the sky. They are pusher-props. The go in a clockwise rotation.
So, when you are buying propellers you have to keep in mind if it's for a plane that pushes or pulls, because they aren't the same thing. They are designed to go a certain direction and you can't simply turn them around because the pitch is really designed to go the direction they were intended to go.
But your ceiling fan can turn in either direction. Why can't a propeller? Your ceiling fan has blades which aren't pitched.
When choosing propellers you need blades that are oriented to the type of plane you have, one with the motor in the back (a pusher) or one that is most common, with the motor up front.
What doe the numbers mean?
There are a set of numbers such as 8/6. The 8 is the diameter of the blade, and the six relates to the pitch. In a perfect world every time a blade spins around once it should push the plane 6 inches forward. Thus a blade that is an 8/4 means that for each revolution you won't go as far. Which is what is needed for planes like park flyers.
Let Josh & Josh school you on propellers.
Back to the ceiling fan example. You ever have one this isn't balanced? At slows speeds you don't notice it. But when you turn it up to full it's bouncing around. That is the problem with propellers as well. Thanks to these new, faster spinning propellers we're flying with a slight imperfection means that your way out of balance and can negatively affect the motor. You need to learn how to balance a propeller.
This is a good video, and guess what, you get to buy more stuff!
Which size propeller is right?
Without much trouble you should be able to find the correct propeller for your motor. The manufacture tends to have suggestions. The little foamies I work with use 8/6 quite often.
I had a problem finding 8/6 pusher propellers. I bought quite a few from APC. They come with an EP a the end of the model number which stands for "Electric Pusher." I bought some 8/6 standard blades which aren't pushers by mistake. They need to go back.
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