My previous discussions of artificial stabilization systems have focused on those used in airborne models. There are also systems available for RC cars and trucks. This time around, I'll share my experiments with one of those units: Spektrum's Active Vehicle Control (AVC) system.
As with all of the other stabilization products I've reviewed, AVC relies on a set of sensors that detect unwanted movements in the model. It then sends commands to the controls (in this case: steering and throttle) to counteract those movements. The end result should be that your model feels less affected by outside elements and more in tune with your control inputs.
The components necessary for AVC are integrated into the transmitter and receiver of several different Spektrum pistol-grip radio systems. The simplest way to obtain AVC is to buy one of the AVC-equipped ready-to-run vehicles from Losi, Vaterra, or ECX. The other option is to install an AVC capable Spektrum radio system into just about any car or truck you choose. To test AVC, I chose the latter route and retrofitted my ECX Ruckus with a new radio system.
The Ruckus was originally equipped with a 2-channel Spektrum DX2E radio – a simple, but reliable system. This radio was replaced by a 4-channel DX4C. Two of the channels operate throttle and steering control, while the remaining two channels are used to adjust the throttle and steering gains of AVC.
The vehicles that include AVC still come equipped with the DX2E. It appears, however, that the radio has been upgraded and includes a different receiver to accommodate AVC. The primary difference I see is that the DX2E has a single gain adjustment that affects steering and throttle gains simultaneously. The DX4C (as well as the higher-end DX4R and DX4S) allows for individual gain control.
The DX4C is a computer transmitter and can store up to 20 different model profiles. So you can add AVC to multiple vehicles by using the same transmitter and equipping each model with an SRS4210 receiver.
AVC places a high demand on a vehicle's steering servo because it is constantly making countless, imperceptible movements to keep the car on track. For that reason, Spektrum advises using a digital servo for steering chores. The Ruckus includes an analog servo, so I swapped it with a Spektrum S6100 unit. With steel gears, ball bearings, 5 times the torque of the stock servo (208 oz-in vs 41.7 oz-in), and nearly double the speed (.13 second transit time vs .23 second) the S6100 is overkill in this application. But it's nice to know that I won't have to worry about it.