Dual Rates-- The Good, Bad, and Ugly
by Clay Ramskill

Usually found on radios with 6 or more channels, dual rates allow you, with the flip of a handy switch, to change how much servo response you get from a movement of your control stick. There is a switch for each channel involved, and an adjustment for each which allows you to "dial in" how much less response you’ll get with the dual rate switch "on".

Dual rate use is fairly simple — with the dual rate "off" you get normal response (full stick deflection = full servo rotation). Turning dual rate "on" , you get only a percentage of the amount of servo movement for the same amount of control stick deflection. The percentage of movement is what you adjust. This is a nice capability — your plane can be set to be wildly responsive for acrobatics, yet with dual rates on, you can fly very smoothly for landing.

THE GOOD: You could set up your plane so that with dual rate ON, the elevator travel is not sufficient to stall the plane, guaranteeing smooth, stall-free flight. Turning the rate back up would then allow snap or spin maneuvers. Some flyers use dual rates only for landing. Dual rates are also great for test-flying a new plane.

THE BAD: Dual rate radios cost a few bucks more. There are more switches to twiddle with and also to check for proper setting before takeoff. AND, in dual rate mode, your servos are not quite as precise as when using full travel, nor quite as powerful.

THE UGLY: The problem is that you get used to a certain level of response from your plane, and expect it all the time. With dual rates, you must always remember which mode you’re in and what the actual response will be.. otherwise, you may not have enough elevator to pull out of that big loop in time, or enough "fast react" response for a landing on a gusty day. The bottom line: If you’re gonna use dual rate, always remember where your switches are set. If you’re NOT gonna use dual rate, check it anyway and if necessary, set it up to give you full control movement regardless of the switch positions.

EDITOR’S 2 CENTS’ WORTH: Many of today’s more sophisticated radios, such as the Futaba 8’s or the JR 8103, allow you to "trigger" dual rate action based on throttle position, so you can set up for high rates (full surface movement) at low throttle, and reduced movement at hight throttle (no switches!)

(Paraphrased from an article appearing in the Yakima Valley Aeromodelers’ Newsletter, edited by Bill Heinson)

This page last updated 08/13/00 18:05