All modern hobby grade helicopters have gyros. In fact, even modern toy 2 and 3 channel helicopters have a gyro.
Regarding the different types of helicopters, they are generally split up into 3 main categories:
- Two sets of main rotors that spin in opposite directions. When they both spin at the same speed, the nose of the helicopter remains stationary. When one blade spins faster than the other, the nose of the helicopter will turn. Forwards, backwards and sideways movement is obtained by tilting the swashplate. They have a fixed pitch, are extremely stable and easy to fly. The downside is that this inherent stability comes at the sacrifice of performance. They move slower, are not be as manoeuvrable and don't handle outdoor conditions well.
- Fixed pitch:
- This term generally refers to a single rotor helicopter that has a fixed pitch. They have a tail rotor to hold the nose of the helicopter in place and to control pivoting. The spinning of the main rotor produces torque which makes the helicopter want to spin on the spot, the tail rotor counteracts this. Speed up the tail rotor and the nose will pivot in one direction, slow it down and the nose will pivot in the other direction. Directional movement is obtained in the same way as a coaxial, via tilting the swashplate. These offer more performance than a coaxial helicopter but require more skill to control.
- Collective Pitch:
- Have a single main rotor and a tail rotor, and also have the ability to alter the pitch of the blades. This means that inverted flight and other stunt type flying is possible (they can flip, roll, loop, fly upside down etc). They offer the most performance but are also the most difficult to fly and configure. You need a great deal of mechanical knowledge on top of flying skill to effectively fly one of these.
The toy 3 channel helicopters are coaxial, and do not have a moving swashplate. They obtain movement via a horizontally mounted tail rotor. If it spins in one direction, this will cause the nose of the helicopter to dip and create forwards movement, when it spins in the other direction, the nose lifts and creates backwards movement. They cannot travel sideways.
There are some rare exceptions to the above, for example there is a coaxial helicopter called the Lama 3 by Walkera that is collective pitch and there is also a 3 channel single rotor helicopter that has a moving swashplate and tail motor, the Double Horse 9100.