So far, we’ve spoken about the angle of attack and how it relates to collective pitch (CP) radio control helicopters – but what goes on “under the bonnet”?
The swashplates on collective pitch RC helicopters differ to those on fixed pitch in a number of ways. For a start, the assembly is more complex: linkages from the swash to the rotor blade grips allow for control of the blades via the servos. In addition, when the collective is engaged, the entire swashplate assembly rises upwards, returning to base when the collective is reduced.
Fixed pitch electric helicopters have their blades set for optimum lift on take-off. However, this is of little use in variable winds, or when hovering. And, of course, it makes landing (when the angle of attack should be lowered) more difficult. This is why they have limited appeal outdoors, and why CP is the preferred medium for 3D flight.
It is true that collective pitch RC helicopters are tricky for beginner pilots to learn on. It’s also true that as far as changing direction (cyclic pitch) is concerned, they work the same as fixed pitch choppers.
However, CP electric helicopters have many advantages over FP. For a start, they have the advantage of totally controllable pitch; meaning sensitivity can be adjusted both for the prevailing weather conditions and for the ability of the pilot.
As well as using the transmitter to adjust the pitch angle of the blades on a minute-to-minute basis, the sensitivity can be dampened or increased via the transmitter settings (this is also true of the cyclic, of course). It is also possible to set the blade pitch manually to allow for varying weather and flying conditions – something that just isn’t possible on a fixed pitch craft.
All in all, if you are looking for a chopper that’s “for keeps”, then collective pitch electric helicopters with digital Tx, are your best bet to choose from. Invest in a training rig and/or simulator program, and the sky is yours.