If you are going to fly helis, get the heli version. Both versions have the same programming, so both will work for helis OR airplanes.
The airplane version, however, is quite different when it comes to placement and function of the various switches found on the top of the TX and on the face, above each stick.
For instance, in the airplane version, the top, front-left corner contains a pushbutton trainer switch. In the heli version, this is a three-position switch that serves as the Flight Mode switch (AUX4) in default mode.
On the airplane version, the top, left-rear switch is a two-position toggle switch that runs the Gear channel. IN the heli version, this is a long, bat-handled momentary toggle switch that is the trainer/timer start-stop switch.
On the face, above the left stick, the airplane version has a three position toggle switch labeled "flap", in the heli version this is the Gear switch and only has two positions.
On the top, right-front corner of the airplane TX, you'll find a two position switch called Aux 4/Rudd DR. On the heli version, this is the rudder dual rate switch.
On the top, right-rear corner of the airplane version, you'll find a two-position Mix switch, on the heli version this is a two position switch used for Throttle Hold.
On the front, right-hand face above the stick, the airplane version has a three position Aux2 switch, this is the same as the heli version.
You CAN use the airplane version for a heli, however the placement of what you would use for a flight mode switch is inconvenient as you would either have to use the FLAP or AUX 2 switches on the front panel. Neither of these is in a convenient place for heli use.
Further, the heli-section of the manual is pretty brief and assumes you are familiar enough with a heli radio that you can easily figure out which of the programmable airplane switches should be used for heli operation.
The sticks contain the basic flight surface and throttle controls. Most radios sold in the US are Mode 2, putting throttle and rudder on the left stick, aileron and elevator on the right stick. The throttle stick in the heli radio is smooth and does not have a ratchet, where the throttle stick on the airplane version is ratcheted (something you would need to disable for heli operation).
If you find the throttle stick on the right along with aileron, and the elevator/rudder on the left stick, you've found a Mode 1 transmitter.
There are a couple of other modes -- Mode 3 and Mode 4, each of which is fairly uncommon (although I know a Pattern Pilot here who flies Mode 4).
If you have the choice and intend to fly helis, I would strongly recommend AGAINST the airplane version, as the switch layout is weird and not "natural" for heli flying. Further, if you need assistance with your heli, you will completely confuse the person helping you and make it very difficult for him to assist you when it comes to flying.
Buy the heli version. Do yourself a favor.
Modes 1, 2, 3, 4 are not necessarily "regional" (US/Europe/Asia...). They are actually based on pilot preference.
Many pattern airplane flyers in the US use Mode 1 as it separates the elevator and aileron functions. As I noted earlier, a local pattern flyer here uses Mode 4. Many of the latest generation transmitters allow the user to select the mode by moving a few mechanical parts and changing some programming assignments.
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