RC Flight Assist Telemetry System

RC Flight Assist Telemetry System

Welcome to LittleCircuit

We present to you one of a kind telemetry system for RC pilots. The RC Flight Assist (RCFA) was designed especially for outdoor pattern flying like F3A or F3M class. The system allows better control over airplane during acrobatics. It implements radio telemetry mechanism that indicates the position inside the flight area with high accuracy. With RCFA the pilot is able to stay in the proper position on the sky resulting better handling and improved skills. The system was tested in cooperation with best polish F3A pilot of the year 2015.

How does it work?

The RCFA system includes two separate electronic devices which are Transmitter and Receiver. Primary role of the Transmitter is to get 3D or 2D position from GPS and altimeter sensors and send the data to the pilot’s Receiver. The Receiver converts the signal into nice sound patterns. The pilot can use build-in sound speaker or headphones to hear telemetry information.

The basic usage of the RCFA is to define two points on the ground to determine flight area. First point (P1) is the pilot’s position – where the airplane will be controlled from. Second point (P2) is the direction to the flight line where the airplane shall be controlled in. These points can be set by walking with the RCFA to desired position on the airfield or by writting coordinates in configuration file (rcfa.ini). The optimal distance between P1 and P2 relay on GPS signal strength and usually don’t have to be more than 20m.


Points P1 and P2 are set within the Transmitter. After it is done, the RCFA system automatically calculates remaining flight area coordinates regarding preset options: the ideal Flight Line (marked with points A, B and C), the Green Zone (green color) and Flight Area (blue color). The pilot’s job is to keep the airplane between the green rectangles:


During a flight the RCFA Receiver generates certain tones that changes accordingly to airplane distance from the green zone. It allows pilot to fast react and steer the airplane to the desired position on the sky. The pilot will know exactly how far from flight line is and also if the airplane is ahead or behind the Green Zone, too high, or too far to the left or right side of Flight Area.


When the flight is over the system will calculate score according to time in the zone and overall flight time. It is automatically stored in kml file. The logger file can be instantly opened in Google Earth (Windows or Linux) to examin the flight and check the scoring.

What else the RCFA can do?

GPS Logger

The system is highly customizable. The user can chage any parameter like distance from pilot to the flight line, area angle, flight plane width and many more (nearly 30 options). It has integrated MicroSD slot for memory card, which is used to store and read area parameters from but also to write positon data as high accurate GPS Logger.

The System implements unique filter algorithms thus the GPS data stream and altitude are high accurate, moreover the RCFA allows to use barometer for even more accurate altitude measurement. It’s accuracy is enough to verify every single figure on the 3D acrobatic fly path. The Logger writes data directly in kml format which can be instantly open in Google Earth software.

Real-time tracking

Another advantage of the RCFA is the ability to stream data to the Receiver about current 3D coordinates through RX/TX interface (USB2TTL). The data stream (longitude, latitude and altitude) can be read and visualized on PC in real-time. This can be organized in several ways. Depending on barometer availability the altitude data can be taken from GPS or barometer. User can choose either the absolute (mean sea level) or relative (to pilots position) altitude readings.


Next feature of RCFA is variometer, which can be used as well in gliders as in any other kind of RC airplanes. The variometer can use GPS data or barometer to indicate altitude changes. The data is send to the Receiver allowing the pilot to control descending or ascending in real-time.