Q: What accessories should I get?

A: There are a million accessories that you can buy. There are a relative few that are indispensable, or almost so. I'd put the following items on the short list: a blade balancer, a pitch gauge, a pair of ball link pliers, and a receiver battery tester. You will need a standard assortment of tools such as needle nose pliers, screw drivers, hex wrenches, etc. You'll also need a starter and starter battery.

A: Definitely not! As a matter of fact, there are techniques used in flying an airplane that can hinder the helicopter learning process. Some of my best students have little or no aircraft experience. Use of the basic airplane instinctive reactions without the correct thought process can be detrimental when flying a helicopter.

Controls on a heli

Q: What is cyclic? Collective?

A: On most R/C helis (and full-scale helis for that matter), the main blades can change their (so-called) pitch angle. What this means is that if you sit the heli on a table and look at the tip of one of the main blades, the chordline of the blade can be tilted through a range of angles by the servos. In this sense, the rotor disk of a heli is a bit like a variable-pitch prop on an airplane. If the heli is hovering and you wish to make it climb straight up, you increase the pitch of the main blades, and increase the throttle so that the engine can overcome the increased drag and keep the blades turning at the same speed. The increased blade pitch results in more lift, and so the heli climbs. (With R/C helis, unlike R/C airplanes, engine RPM's are supposed to stay the same over (most of) the throttle range. At high throttle the engine puts out more power, but there is a corresponding increase in the load on the engine due to increased main rotor blade pitch, and so the engine stays at the same RPM's.) This overall increase in pitch that makes the heli climb is called collective control.

To get the heli to pitch forward or back, and to roll left and right, there are controls that are analogous to airplane elevators and ailerons. These controls are referred to as cyclic controls. The idea is to set up asymmetric lift on the rotor disk. (This is similar to what ailerons do to an airplane-one wing can be made to generate more lift than the other, and so the airplane rolls.) If there's asymmetric lift on the rotor disk, the plane of rotation of the rotor disk is going to change. For instance, the rotor disk (and the heli that is attached to it) might go a bit nose-down. In that case, the heli will transition out of a hover and start flying forward. Similarly, the heli can be made to lean back (nose-high), left, right, or any combination of these. The way this asymmetric lift is set up is to vary the pitch of each blade as it goes around. For instance, say you push forward on the cyclic control stick (the right one on your transmitter, which does the same thing as an aileron/elevator control stick on an airplane radio). This will make the blade pitch down as it travels through the forward-moving part of the rotor disk (usually the left side of the rotor disk), and it will make the blade pitch up as it travels through the backward-moving part of the rotor disk (usually the right side of the rotor disk).

Q: What do the servos control?

A: There are usually five servos on an R/C heli. One controls throttle, one controls collective, one controls fore-aft cyclic (analogous to elevator), one controls left-right cyclic (analogous to aileron), and one controls tail rotor pitch (analogous to rudder).

Q: What is the use of gyros and how do they help?

A: The gyro is positioned so that it senses yaw. It then feeds small inputs to the tail rotor servo to counter the yaw that it detects. This keeps the helicopter from yawing to the left and right when you don't want it to. Left-right movement of the left stick also supplies input to the tail rotor servo; so you and the gyro are both giving control inputs to the tail. A gyro is a MUST. It's probably not an exaggeration to say that gyro-based stabilization of the tail rotor made R/C heli flying feasible. It is possible to fly an R/C heli without a gyro, and it's also possible to juggle seven balls. It's just darn hard! Furthermore, it's definitely not something you want to try tackling when you're just getting started. Without a gyro, the heli can begin to whip around wildly as soon as the skids leave the ground. The heli will do a 180-degree turn and you're looking at an angry helicopter coming right at you before you know what happened. Definitely not something for a beginner to tackle.