Futaba S-CD500KS knuckle servo: Team SHIBATA details its 1/10 drift settings

Photo: Futaba (source)

The Futaba S-CD500KS knuckle servo is back in the spotlight: Team SHIBATA has just released several setup videos in a row devoted to this rather unusual servo, intended for 1/10 two-wheel-drive electric drift. Enough to shed light on a product that overturns a forty-year-old certainty: the steering linkage.

The Futaba S-CD500KS knuckle servo does away with the steering linkage entirely

The principle of the S-CD500KS is radical: the servo is the knuckle. One housing is mounted on each front upright and directly actuates the corresponding wheel — so two are needed per car. The direct consequences announced by Futaba: no more tie rod, and therefore no more toe variation over suspension travel (bump steer), no more mechanical linkage parts, and therefore weight savings, plus movement that stays smooth even at very large steering angles, exactly what drift demands.

Every adjustment goes through the transmitter and the GYD560 gyro

As each wheel is driven independently, the steering geometry becomes a software parameter. From a compatible transmitter, Ackermann rate and travel limits are adjusted wirelessly wheel by wheel, with a twelve-point Ackermann curve on each side, and toe angle can even be mixed onto the brake or throttle trigger.

The setup does, however, require a precise ecosystem: the Futaba GYD560 gyro in version 2.0 or above, and one of the T10PX, T10PXR, T10XCR or T6PV transmitters brought up to date (16.0 minimum for the T10PX/T10PXR/T10XCR, 4.0 minimum for the T6PV). Watch the power supply: the speed controller’s BEC must be set to 6.0 V, as a 7.4 V output destroys the servo.

What Team SHIBATA shows in its videos

The series published by the driver nicknamed Pinkman first covers fitting the knuckle servo to a GRK5 chassis and the basic configuration, then a tuning session in which the servos’ internal parameters are left as they are — those used by Team SHIBATA drivers — with the work focusing mainly on the gyro side. A GoPro onboard video completes the demonstration by showing how the steering behaves in a slide.

Specifications of the Futaba S-CD500KS knuckle servo

• Use: steering for 1/10 two-wheel-drive electric drift cars — 2 servos required per car
• Dimensions: 32.0 x 16.6 x 27.6 mm — weight 20.7 g
• Speed: 0.130 s/60° at 6.0 V — 0.165 s/60° at 4.8 V
• Torque: 2.4 kg.cm at 6.0 V — 2.0 kg.cm at 4.8 V
• Operating voltage: 4.8 to 6.0 V — lead length 330 mm
• Supported modes: UR and SR
• Supplied accessories: axle shafts, upper rod ends, spacers, M2 nuts and screws
• Not supplied: wheel hubs, hub pins and 10 x 5 x 4 mm bearings (2 per servo)
• Part number for the 2-piece set: 042089 — 39,600 yen