Click image to enlarge.

The control-function labels have been rearranged to illustrate how a Mode I control-stick configuration would look.

Bob's trusty 12-year-old Airtronics Vision RC transmitter employs the popular Mode II control-stick configuration.

This is Bob’s only remaining single-stick configuration RC transmitter. It is an Airtronics Championship series dating back to the mid-1980s. The black box marked "SR" on the left side is an added auxiliary battery pack from SR Batteries to considerably extend the transmitter’s operating time. This was very popular with the RC sailplane enthusiasts.

Q-31: I have seen references to RC transmitters that operate on Mode II and Mode I. What are they referring to?

A-31: They are referring to the transmitter's control stick configuration. The majority of RC transmitters flown in the US today employ what we call the "Mode II" control-stick configuration. This is what you will see in use at most local flying fields throughout the country.

In the Mode II arrangement, the right side, dual-axis control stick provides for aileron (side-to-side stick motion) and elevator (up-and-down stick motion). The left stick assembly provides rudder control (side-to-side stick motion) while the throttle control stick moves up and down. The spring return has been removed from the throttle stick and a detent device employed so that the throttle always remains where you set it.

Present-day RC manufacturers have told me that 8-10% of the RC modelers in the US still use the less-common Mode I control-stick configuration. With this arrangement, the right-side transmitter control-stick assembly provides aileron and throttle control, and the left stick assembly controls the elevator and rudder.

The idea behind this is to separate the two basic flight controls—ailerons and elevator—so that the right hand operates the ailerons and the left hand controls the elevator. I understand that the Mode I control-stick configuration is more popular throughout Europe and the Far East. I guess depends on what you are used to.

Through the years, several modelers have asked me to help them fly with a Mode I transmitter, and believe me, it took all of my concentration to handle it. Many current RC transmitters can be set to Mode I configurations, although the conversion usually entails sending the transmitter back to the factory. As a minimum, the throttle detent must be moved from the left to the right control-stick assembly.

Phil Kraft—Kraft Systems founder and national and international RC Aerobatics champion—always flew with the Mode I stick configuration. The choice is yours, but it is better to stick with the majority, especially when you are a beginner and must seek help from other pilots who most likely will be Mode II fliers.

Years ago, another popular RC transmitter provided full four-channel control from a single three-axis control stick. I flew that type of system for more than 20 years, until it finally became extinct.

With the single-stick transmitter, you held the case with your left hand, sort of cradling it. Your right hand gripped the control stick. A side-to-side motion controlled the ailerons. An up-and-down motion operated the elevator, and if you rotated the entire control stick at the same time, you obtained rudder control. Your left hand's index finger operated a throttle lever on the side of the transmitter’s case.

I felt quite comfortable with this arrangement, but I was the odd man out since no one else at my flying field knew how to fly a single-stick transmitter. Single-stick transmitter popularity ultimately diminished and the cost of the complicated control stick made the prices go up. I still own a single-stick transmitter—an Airtronics brand—but seldom use it anymore.

—Bob Aberle