How to program flight modes/conditions on your radio
by Jim Hiller [email protected]
What are these things called flight modes and how should I use them to make the task of flying my complex model easier? That is the question you should ask yourself if you're flying a jet with a modern computer radio.
The intent of flight modes (if you are flying with JR or Spektrum radios) and flight conditions (if you are flying with a Futaba radio) is to reduce the pilot's workload. Let's discuss them and I'll explain how I set up my models using flight modes to fine-tune for landing, takeoff, and normal flight—all on one switch.
I fly with a JR 12X, but the Spektrum DX18 is similar. All radios have comparable features, but different ways to accomplish the same goals.
My setup preference on jet models is to assign flight modes to the flap switch, naming the up position as normal flight, mid-position as takeoff, and down position as landing. Assigning names to the flight mode is important because I am setting more than flap positions with this switch. I am also setting all flight conditions I want for taking off, landing, or flying.
You could program additional flight modes, but let's not complicate things more; dialing in these three flight modes is complicated enough.
Start your setup in the System Mode List. On the JR 12X, you get to the screen by holding down the Enter (ENT) button as you turn on the radio. In the Spektrum DX18, it's available on the Menu screen, which is helpful and convenient.
On the JR 12X, go to Device Select (Device SEL) and assign the flight-mode switch to the flap switch. You can later use the extra feature to have additional flight modes active in combination with another switch. Scroll down to Flap Trim Off, then scroll down again and trim to Flight Mode (FMOD). This allows you to individually trim your model for each flight mode.
Exit the Device SEL screen and move to FM Name, while still from the System Mode list, to name the flight modes. The up switch is FMOD-0; name it flight. Mid position is FMOD-1 and is named takeoff, and FMOD-2 is for landing. The flap switch will act as your flap-mode selection switch. The active flight-mode names will appear on the transmitter information screen.
Return to the information screen and the Function List Menu to set up the model's control throws. My preferences for flap travel (setting up on the flap switch) are: up is normal flight with flaps up; mid is takeoff flaps with approximately 10° of flap; and down is full flap from 30° to 60°, depending on the aircraft. Moving the flap switch should make the flaps move and change the flight mode.
Continuing our setup in anticipation of the first flight, let's set the control throws. I keep my elevator and aileron dual rates on individual rate switches for the first flight. My mid rates are set to the manufacturer's recommendations.
Low rates are set slightly less and high rates are set to provide additional control if something is off and I find myself running out-of-control travel during test flights. Additional elevator travel on high rates could make a safe landing possible when normal travel isn't enough to hold the nose up for landing.
If you are test flying a well-proven design with known rates, go straight to those travel rates. I like to put elevator and aileron dual rates on a common switch, which is the left dual-rate switch.
Flying
It's time to fly! Let's walk through the flight and what we need to accomplish.
First, on back taxi out, trim the nose-gear steering. Remember that all trim corrections must be copied over to each flight mode, especially for takeoff and landing flight modes. Line up on the runway and take off.
On my first flight, I typically use flap-up flight mode. Upon liftoff, I get the landing gear retracted and concentrate on the basic trimming of the model's control surfaces: ailerons, elevator, and rudder. I do not use takeoff flight mode at this time. I'm only ready to concentrate on necessary, immediate trim corrections.
If the model required an additional up-trim of 30 clicks shortly after takeoff, that's a lot of correction. By taking off in up-flap flight mode, I immediately deal with the elevator trim. The airplane should be cruising around, perfectly trimmed for level flight.
Check out the dual rates and find what rate you like for normal flight mode. We will later make that set rate when in the flight-mode setting.
Slow the airplane, extend the landing gear, and set it to takeoff mode. Getting the airplane back on the ground means it's time for more programming—this time to set up the control rates on the flight-mode switch. I like to set up the dual rates over the flight modes, which can be accomplished from the Dual Rate function in the Function List.
On a JR 12X radio, open the Dual Rate and Exponential (D/R and EXP) screen, then scroll to the far right side under the AUTO column, to FM-0 (the flight mode), and assign which dual-rate position you want for this flight mode. Continue down and assign the dual-rate positions for FM-1 (takeoff) and FM-2 (landing), completing the flight modes setup. You now have the trim settings and control throws for flying, landing, or taking off set on your flight mode/flap switch.
Flight modes are a nice convenience, reducing the workload during critical times in flight. They are slightly complicated to set up, but can simplify flying. If the radio manuals don't help you understand these features, contact the manufacturer.
SOURCES: Jet Pilots Organization www.jetpilots.org
Transcribed from original scans by AI. Minor OCR errors may remain.
