RC helicopters have become so popular that many new enthusiasts everyday pop up every day. When they go to purchase thier first radio controlled helicopter, many of these beginners are puzzled when they find that RC helicopters come labeled either as " fixed pitch" or "collective pitch". Let's see if we can explain what exactly the difference between the two is.
To understand how the two pitch setups differ, one must first know what "pitch" means. The "pitch" of an RC helicopter is the
angle of cut of the main rotor blade. The measurement of the
"pitch" angle is done relative to the horizontal plane in which the blade or rotor spins. Helicopters
generate lift by spinning their rotor through the air. With a fixed
pitch helicopter, when the rotor spins faster, it generates more lift
and the helicopter rises. The converse of that is slower rotor rotation
generates less lift and the helicopter descends. For the collective pitch helicopters, the pitch of the blade adds another dimension in the
lift generating equation. In this setup, the lift can also be controlled by changing the angle (pitch) in which the main rotor blade is positioned. Another way to describe it; While the rotor is rotating at a constant speed, the
lift generated can be altered by changing the pitch alone. This is the same principle of a full size helicopter operation.
Knowing the technical difference between the two pitch setups,
the next logical question is: how does this affect flight? Quite simply, a
collective pitch helicopter is more responsive, agile, and smoother to
fly. There is a tradeoff. They have a much steeper learning curve and are harder to learn.
They also require a more complicated transmitter, and cost a good bit more than fixed
pitched helicopters. There are more more moving parts, which means they
break more easily and requires more maintenance.
Which one should you choose to fly? Fixed pitch or collective pitch?
This boils down to a matter of personal choice and how serious you are about this
hobby. A fixed pitch helicopter has fewer moving parts, and is more
ideal for the beginner as it requires less maintenance. Also, most of the helicopters that are
fixed pitch comes in an RTF (Ready to Fly) kit, and usually includes the radio transmitter suitable only for a fixed pitch model.. If you plan to stay in this hobby for a long time and fly in
more demanding ways, then perhaps making a bigger investment and
getting a collective pitch helicopter will be worth while. In my personal opinion, with the purchase price of a light, fixed pitch rc helicopter usually as low as $30, then it makes sense to start with the simpler version and become somewhat familiar with the flying environment of the RC helicopter. Then when you have mastered that level, move on to the more difficult collective pitch RC helicopter.