Selecting the right propeller.
It goes without saying that selecting the right propeller size for your RC airplane is very important if you want to get an optimum performance from your IC engine/electric motor and plane.
In the worst-case scenario, the wrong prop can cause serious damage to components and this is especially true for electric powered RC airplanes.
The imaginary disc (arc) created by the spinning propeller is the length of the propeller from one tip to another tip. The pitch measurement of a propeller indicates how far (in inches) a propeller will move through the air per single revolution of the engine. However, the pitch measurement of your propeller must only be taken as a guideline because real life factors come in to play that influences distance for example, the material of the propeller, its condition, efficiency, air density etc. Therefore, the pitch measurement is really only a theoretical value but it is good enough to help you choose the right size propeller for your airplane and your needs.
Essentially, the higher the pitch value, the faster your plane will go. One way to understand propeller pitch is to imagine the gauge of two different screw threads, coarse and fine, and picture both being screwed into a piece of wood at the same rotational speed. The screw with the coarse thread will cut into the wood a lot faster than the fine threaded screw.
It’s the same for propellers ‘cutting’ through the air (hence the reason why propellers are sometimes called airscrews). The two arrow lines represent the path of each propeller tip. You can see that a higher pitch prop (ex 10x8) takes only one and a half turns to cover the same distance than the lower pitch prop (ex 10x4) that takes 3 turns. So, with both engines and propellers spinning at an identical RPM, the higher pitch propeller will travel further in the same amount of time, hence a faster flying plane.
Thus, selecting a different propeller pitch size is going to significantly change your airplane’s performance, with speed being the primary factor.
Stainless Steel vs Aluminum
Aluminum propellers usually cost quite less. However, stainless steel is over five times more durable than aluminum. If you are looking for a quicker acceleration, superior top speed, or better overall performance, you should consider a stainless-steel propeller. Aluminum propellers are not expensive, they work well and are relatively easy to repair but aluminium isn’t particularly durable, making aluminum props susceptible to wear and damage. Stainless steel propellers cost more, stainless steel is stronger than aluminium, a stainless propeller blades are usually thinner and can be made in a wider variety of style and shape than an aluminum propeller, thus the potential for better performance and increased service life.
