No problem being a noob... we all started out somewhere..

Props. Well, perhaps this will help. Props come in sizes, usually measured in inches, perhaps in your area, they are metric.. however, I'll relate it to you as I see it so I don't get the numbers wrong...

Props, as I said, come in sizes. For instance, take the 13-7 prop. That is 13 inches in diameter with a 7 inch pitch. The diameter is self explanatory. The pitch takes some explanation. In this case, a 7, (the second number in the prop size) is the prop pitch. This is the theoretical amount of travel for one complete 360 degree rotation in inches. So, if that prop turns one complete revolution, it will move 7 inches in the air or move7 inches of air through it.

So, ideally, if it is operated at full throttle, take 10,000 RPM for instance, that means that the prop will rotate 10,000 times, or 70,000 inches of air in one minute. That's 5833.333 feet per minute or 97 feet per second, which equates to slightly over 60 miles per hour.

That's the theory of it. Also, consider this. The pitch of a prop is like the gears of a transmission in a car. If you down-shift to a lower gear, then you can pull harder but at a lower speed. As you shift up, to second, third, fourth, your engine has a lower RPM but the car is going at a faster rate, but it does not have the same ability to accelerate as fast as it did using a lower gear.

The prop works the same way. Lower the pitch, you will have faster acceleration, but a lower top end speed, but you will also pull harder. Your plane will get off the ground faster, but it will not go as fast as it would with a higher pitch.. however, the higher pitch will cause you to accelerate at a slower rate than the one with a lower pitch.

You have to work out what you want and what is ideal for your flying style. If you want 3D, for instance, you would tend to use something with a lower pitch to get that instant burst of acceleration plus the power to hold a plane in a hover. If you are doing sport flying and don't give two hoots for 3D, then you would move up in pitch to give you better speed, but less initial power. It's a trade off.

Hope that helps.

CGr.