23.2. From the transmitter to the lower swashplate

There are three systems which are widely used to control the lower swashplate from the transmitter:

23.2.1. Mechanical Mixing (mCCPM)

For mechanical mixing, there are three servos that control the lower swashplate indirectly through a mechanical mixer.

So, the transmitter sends separate signals for fore/aft cyclic, left/right cyclic, and blade pitch.

The servos for these functions plug directly into the receiver channels. The control horns for the servos are connected to the mechanical mixer which mixes the movement of the individual servos into the lower swashplate movement.

The fore/aft servo output goes to the mechanical mixer, and its motion is converted into the fore/aft tilt of the swashplate.

The left/right servo output goes to the mechanical mixer, and its motion is converted into the left/right tilt of the swashplate.

The pitch servo output goes through the mechanical mixer, and its motion is converted into the swashplate height.

The most common type of mechanical mixer is the type used on the Raptor and T-rex helicopters. This consists of a "rocker arm" of which one side is connected to the swashplate. The left/right servo is mounted inside the other side of the swashplate, and the fore/aft and pitch servos are mounted under the rocker arm.

The ECO 8 when configured for a mechanical mixer uses a "sliding platform" type of mixer. This mixer performs all the functions of a rocker arm mechanical mixer and also performs revo mixing as well, so there are four servos connected to this type of mechanical mixer.

23.2.2. Electronic Mixing (eCCPM)

For electronic mixing, there are three or four servos which are directly connected to the lower swashplate which control the height and tilt of the swashplate.

There are usually three servos which are connected to the lower swashplate at 90 or 120 degrees apart, although there are variations which use four servos or have the servos placed 140 degrees apart.

So, the transmitter reads the stick positions and performs calculations internally to determine the positions of the servos to create the correct swashplate height and tilt.

These servo positions are transmitted to the receiver which sends the information to the servos.

The movement of the swashplate is the same as with mechanical mixing. The fore/aft cyclic controls the fore/aft tilt of the swashplate, the left/right cylic controls the left/right tilt of the swashplate, and the pitch controls the height of the swashplate.

The Logo 10, ECO 8 configured for electronic mixing, Hummingbird Elite CP, Hornet CP, and other helicopters use this system.

23.2.3. non-CCPM

For a non-CCPM control system, there are two servos which are directly connected to the lower swashplate, and a third servo which directly controls the main blade pitch.

So, the transmitter sends separate signals for fore/aft cyclic, left/right cyclic, and blade pitch.

The servos for these functions plug directly into the receiver.

The fore/aft servo is directly connected to the lower swashplate and controls the fore/aft tilt of the swashplate.

The left/right servo is directly connected to the lower swashplate and controls the left/right tilt of the swashplate.

The pitch servo is not connected to the swashplate and controls the main blade pitch through a separate mechanical connection.

From the transmitter's point of view, the mechanical CCPM and non-CCPM control systems are identical, because both have independent servos for collective pitch, fore/aft cyclic, and left/right cyclic.

On the Zoom 400, the main shaft is hollow, and there is a rod which runs through the main rotor shaft and controls the main blade pitch.

On the Piccolo Pro, the there is a hollow tube which goes around the main shaft and inside the swashplate and controls the main blade pitch.