back					MAXIMUM CONTROL RADIO SET-UP
		Maximum Control 10 Easy Radio Setups by John Reid     From the November issue of Model Airplane News Computerized radios have changed the way we control and set up our models. They allow us to fine-tune our planes to suit our flying abilities, and when you open such a radio’s manual, you’ll read about an abundance of functions. Even entry-level computer radios offer an array of user-selectable programs and mixes. But which computer radio is right for you? We selected our top 10 features; they will enhance every pilot’s flying abilities and allow his plane, regardless of its type, to fly better. 1. DUAL RATES Dual rates allow you to set different control authority for the same amount of stick movement. Computer radio systems offer one to five rates. For example, if your radio offers three rates, you could set the low rate for 50-percent servo travel to fly smoothly at high speeds without too much control authority; the mid rate will give you a little more control authority (about 75-percent servo travel) for landings and aerobatics; and the high rate could be set for 100-percent servo travel for high-alpha maneuvers and extreme 3D aerobatics. This is where you’ll need all the deflection you can get from those control surfaces. 2. EXPONENTIAL Exponential is often used with dual rates, and it gives a softer feel at center stick. This is especially useful when the rates are set high because extreme throws will make the control sticks very sensitive. The slightest movement at center stick will cause the plane to react and to fly a somewhat erratic path. Exponential allows little, if any, servo movement at center stick, but it will increase exponentially until 100 percent of the control- surface movement is reached at full stick travel. 3. TRAVEL ADJUSTMENT Also referred to as adjustable travel volume (ATV) and endpoint adjust (EPA), this function allows you to adjust a servo’s total travel in both directions. You can use this adjustment to set the maximum control throws that you need for flying. Just be careful not to set so much servo travel that it binds by trying to move the control surface beyond its physical limitations. Travel adjustment also allows you to set more throw in one direction than in the other. This is useful when you need more control authority in one direction—for example, having more down-elevator than up- elevator to achieve symmetrical inside and outside loops. Program Mixing Program mixing can really improve an airplane’s performance because it allows you to have one transmitter control movement affect the response of two or more channels on the receiver. Depending on the radio, you can set the mixer up to respond to a control stick, a rotary knob, a sliding lever, or a toggle switch. Mixers are generally used to correct the flight characteristics you don’t want and improve the ones you do want. Use them to make your plane fly exactly as you want it to. Program mixers work by mixing two or more receiver channels for one control movement on the transmitter. The master channel is the input channel, and the slave channel is the one affected by the mixer. How much slave-channel movement you have can be adjusted and specified by the mixer program. Among the most common mixes are: 4. FLAPERONS This function is used with separate aileron servos (one in each wing panel) to control both ailerons so that they work together, in opposite directions. The ailerons can be independently adjusted for travel, direction and servo speed. Flaperons can also be used to allow strip ailerons to be used as flaps. Strip ailerons can also be deployed upward to give spoileron control to help with high-alpha maneuvers and at slow speeds for spot landings.
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5. DUAL ELEVATORS Having a servo for each elevator is very important,
especially on large-scale aircraft, because a lot of force is imposed on the
elevators during flight. Using separate high-torque servos also adds an
additional level of safety. Each servo is plugged into its own channel, and the
servos work together and share one trim lever. Dual elevator control also
allows one of the servos to be reversed if needed to keep all the control
linkages and geometry identical.












6. DUAL ELEVATOR AND FLAP MIXING Programming the elevator channel as
the master and the flap channel as the slave will allow the flaps to deploy
when you move the up-elevator stick. Used mostly with fun-fly aircraft, this
function allows a plane to fly tighter loops. With scale aircraft, you should
have the flap channel as the master and the elevator channel as the slave to
provide automatic elevator compensation—upward or downward—when the
flaps are deployed (as shown above).

7. RUDDER TO ELEVATOR/AILERON. This mix is used to compensate for
unwanted roll or pitch coupling during knife-edge flight. The mixer inputs the
appropriate amount of elevator and/or aileron to keep the plane on a nice,
straight, knife-edge flight path. This is especially important for aerobatics
flown close to the ground. The pilot has to worry only about the rudder stick
without dealing with elevator and aileron corrections. Reducing the pilot’s
workload greatly lessens risk to the aircraft—and the pilot’s ego!

8. AILERON/DIFFERENTIAL. This is the ratio of up to down movement—the
throw—of each aileron. Because the airflow efficiency at the top and the
bottom of the wing differs, many airplanes require more upward aileron
deflection than downward deflection. By programming in more upward
deflection, you can eliminate unwanted yaw when you move the aileron stick.

9. AILERON TO RUDDER. Programming in an aileron-to-rudder mix means
that any aileron-stick deflection will also cause the rudder servo to move in
the same direction. The percentage of rudder deflection is programmed into
the mixer by the pilot. This cooperative movement of the aileron and rudder
allows most airplanes to execute scale-like turns, and it prevents adverse yaw
with high-wing and scale models.

10. FLIGHT MODES. 10Flight modes. A flight mode is a configuration that’s
designed to help the pilot and aircraft fly with the optimum settings. Think of
flight modes as a one-switch-does-everything function. You can program the
flight modes for takeoff, landing, flying at normal speeds, high-speed flying,
slow-flight maneuvers, 3D flight and any other flight settings you may need.
The idea here is to program each flight mode to provide the ideal aircraft
configuration for a particular task. With a flip of a switch, you can have the
plane go into landing mode, which could include lowering the flaps, lowering
the retractable landing gear, adjusting the elevator and aileron to compensate
for the extra drag and moving all the servos to high rates to allow responsive
control movements at the slower speed. Having one switch control all these
simultaneously reduces the pilot’s workload and allows him to concentrate on
flying.
Take the time to program in at least some of these functions and try them out;
if you don’t like how your plane responds, just erase them. But I’m willing to
bet that once you try them, you’ll like what they do for your flying and will
program them in for all of your other models.