RC drift gyro setup: what the gyro does and how to set gain

A drift gyro senses the car's rotation (yaw) and uses the steering servo to turn the front wheels against it. Mount it flat on the chassis. Check that it corrects in the right direction before you drive. Set your radio as the gyro's manual says, then set the gain. Makers' starting points range from about 50% to 70%, and if the steering starts to shake, turn the gain down.

The gyro is wired between the receiver and the steering servo. That is Yokomo's wording for its YG-302V2, and every drift gyro we read works the same way. It measures how fast the car is rotating and adds counter-steer to the servo signal. Futaba describes the sensor in its GYD550 as a "MEMS vibrating structure gyro."

Makers split the work between gyro and driver in different ways:

• Futaba offers two modes. In NORMAL, "The driver needs to perform counter-steer." In AVCS, the "Gyro performs countersteer," and you "Steer in the turn direction." The manual says AVCS control is "firmer," and leaves the choice to you.
• Yokomo's DP-302 V4 has a Normal/ASSIST switch. Yokomo's product page says ASSIST gives "strong correction" so that even beginners can enjoy RWD drifting. In NOR mode, "the driver's steering input is prioritized."
• Rêve D's REVOX has a six-step "gyro curve." A higher setting applies more assist from the start of the drift, which Rêve D says makes the car "harder to spin" and improves straightness.
• KO Propo's KG-X had a "Priority Control Adjuster" dial that set the balance between the gyro's signal and your steering. The KG-X is now out of production.

What a gyro cannot do is fix the car around it. The open-source OpenDrift RC project puts it plainly: "The gyro cannot repair an unstable chassis, a buzzing servo, steering bind." You still choose the line and the throttle.

Most drift gyros take two inputs from the receiver:

• Steering comes in on channel 1 and passes through the gyro to the servo.
• Gain comes in on channel 3, so you can change it from the transmitter while the car runs.

Futaba's GYD550 manual says "The transmitter needs 3 or more channels to control the gyro gain." Rêve D says the REVOX works only with radios of 3 channels or more, and that the channel-3 control "needs to be the dial type." Yokomo's YG-302V2 also works on a 2-channel radio, but then you set the gain on the gyro, not from the transmitter.

Some receivers have the gyro built in. Radiolink's R6FG receiver ships with its gyro switched off, and you turn it on from the binding button. Kyosho's FAZER D2 readyset uses a receiver whose gyro, Kyosho says, controls both steering and throttle.

The manuals agree on most of this:

• Futaba: fix the gyro with the supplied double-sided sponge tape, "level so that it is not tilted relative to the chassis," where there is "as little vibration as possible." Keep it away from heat sources, including the motor, ESC, battery and servo. Its rotation on the chassis "can be any direction within 360°."
• Futaba GYD560: the gyro "is sensitive to vibration," and tape other than the supplied tape can cause a malfunction. This is from the Japanese manual, in our translation.
• Rêve D: stick it "direct to your chassis, in a place away from vibrating electric parts like servos, cooling fans, and motors."
• KO Propo: the KG-X manual shows a horizontal mounting as correct, and a vertical one as wrong.

Some community guides say to mount the gyro at the centre of the chassis. None of the maker manuals we read says that. They ask for level, firm and away from vibration.

A reversed gyro steers the wrong way, and it does it at once. Futaba's GYD560 manual warns that if you drive with the direction reversed, the car "will spin violently in one direction" (our translation). Its GYD550 manual simply says: "Always check the direction of operation of the gyro." Super-G's review of the REVOX adds that its reviewer had to reverse the direction after installing the gyro per the instructions.

1. Switch on with the car still. The GYD550 needs 3 to 5 seconds to initialize. "Do not move the car and do not move the steering wheel" during that time. The GYD560 manual says about 3 seconds, and KO says the car must be standing still.
2. Turn the car to the left by hand. The front wheels should steer to the right. Futaba's GYD550 manual and Radiolink's manual both describe this test.
3. If the wheels follow the rotation, reverse the gyro. Use its reverse switch or setting: SW2 on the Yokomo V4, a 3-second press of the setup switch on the REVOX, or "Gyro reverse" on the Futaba.

Set the servo travel limits and the transmitter before you touch gain. The details differ by maker, so follow your own gyro's manual:

• Futaba GYD550: make "the servo operating range as wide as possible," with the endpoint (EPA) values equal left and right. Do not use trim, sub-trim or mixing; set the neutral with the gyro. The gyro stores its own steering limits, and "If the limit is too narrow, the steering operation will be adversely affected."
• Futaba GYD560: set EPA and D/R to 100%. If you must use trim, set the gain to zero first. The manual warns that with too little steering angle you "cannot get sufficient gyro effect." It says to adjust the linkage for maximum angle without binding (our translation).
• Rêve D REVOX: set the steering channel's EPA to "55 or higher" and channel 3 to 100. You then set the endpoints on the gyro itself.
• Yokomo DP-302 V4 and KO KG-X: set the steering endpoints on the gyro. KO says this is to protect the linkage and knuckle.

Gain is how hard the gyro corrects. On most units you set it with the channel-3 dial, and the dial's direction can also choose the mode:

• On the GYD550, the plus side selects AVCS and the minus side NORMAL. The size of the channel's endpoint sets the gain: +55% gives 50% gain, and +110% gives 100% gain.
• On the Yokomo V4, 0 to −100% is Hard mode, 0 to +100% is Soft mode, and 0 means no gain. The English manual calls Hard mode "Suitable for most of users," and the Japanese text says it is for beginners.

The gyro can only correct as fast and as far as the servo moves. Check compatibility first:

• Futaba's GYD550 is "Only for Futaba digital servo. Analog servos cannot be used."
• The GYD560 accepts brushless (BLS) and digital servos.
• Yokomo marks the DP-302 V4 "for digital servos only."

As an example of a servo sold for drift, Futaba lists its HPS-CD701 at "0.045sec/60°(7.4V)" and "17.0kgf・cm(7.4V)." OpenDrift's point applies here too: "more gain cannot add authority."

• Driving before doing the direction check.
• Moving the car or the steering wheel while the gyro initializes.
• Trimming the steering at the transmitter when the manual says to set neutral on the gyro.
• Copying another driver's gain number from a different gyro, surface or track.
• Turning gain up to cover a chassis problem: bind in the steering, a tired servo, or a car set up for a different surface.
• Mounting the gyro next to the motor or ESC, or on tape other than the supplied tape.

Which RC drift gyro is best?

There isn't a single answer. The current gyros we read — Futaba's GYD560, Rêve D's REVOX, Yokomo's V4 and YG-302V2, and Sanwa's SGS-02 — share the same basics. Choose on three things: whether it supports your servo, whether your radio has a spare channel to adjust gain, and whether you want the gyro or your own hands to do more of the counter-steer. Futaba's GYD550 and KO's KG-X appear in older setup advice, but both are discontinued.

What does AVCS mean?

Futaba's manuals don't expand the acronym. They describe what it does: in AVCS mode the gyro performs the counter-steer, and you steer in the direction of the turn.

Is using a gyro cheating?

No. Every ready-to-run RWD drift car in our getting-started guide ships with one. The retailer RC Team calls it a "tool for progress, not a crutch."

Do I need a 3-channel radio?

To change gain from the transmitter while the car runs, yes: Futaba and Rêve D both require 3 channels or more. Yokomo's YG-302V2 also runs on a 2-channel radio, but then you set its gain on the gyro.