All rc aircraft, with the exception of gliders, required equipment to run and maintain their complicated and often temperamental gasoline engines. Up to a certain size of aircraft, the available gasoline engines of the time did not produce a high power to weight ratio. Thus, performance and maneuverability were somewhat limited for anyone who did not want to invest in a very large model. To make the problem even worse, crashing on of the early gas powered rc helicopters meant that the owner would have to spend a small fortune repairing the machine back to airworthy status. The rc electric helicopter came of age when advancements in micro circuitry allowed the miniaturization of the complex control electronics contained within the rc electric helicopter itself.
Where once a heavy battery pack, radio unit and several large servos were necessary, the entire package could be safely placed in a helicopter weighing in at not more than 50 grams. Today, the basic hardware that makes up the heart of the rc electric helicopter can be placed in outer “shells” which represent fanciful helicopter concepts, actual military and civilian machines, and even insects and birds.
Several types of rc electric helicopter are available, each one offering certain advantages and disadvantages over the other-
First, the conventional single main rotor and tail rotor rc electric helicopter offers the simplest, probably the most responsive flight characteristics. This is not surprising, as this layout is actually the most commonly used in real helicopters. Unfortunately, the lack of a real swash plate underneath the main rotor limits these rc electric helicopter models to moving slowly forward due to a well-placed nose weight.
Next, there are quite a few coaxial rotor rc electric helicopters, which have two main rotors contra-rotating along a common rotor mast, much like the Russian Kamov helicopters which now serve aboard war ships o the Russian Navy. Like their full-size counterparts, no tail rotor and related hardware is necessary, but such rc electric helicopters do have a tendency to become unstable from mismatched gyroscopic forces caused by the two rotors.
There are also a considerable number of twin-tandem rotor rc electric helicopter layouts, patterned directly after the US Marines’ ch-46 sea-knight and the massive US Army ch-47 chinook. These are some of the most realistic looking, but suffer from considerable yaw uncontrollability. Also, making coordinated and predictable turns with these machines is nothing short of a struggle.
Then, there are also versions of the first two layouts, which incorporate a small, vertically-mounted rotor on the tail, which lifts the tail up, tilting the main rotor forward and causing the rc electric helicopter to go forward. This arrangement produces what is probably the most maneuverable rc electric helicopter of the lot, but going forward for prolonged periods of time drains the battery very quickly.