GAPTER: First Flight Tests

This section should describe the process to make some flight tests in indoor and outdoor environments with Gapter.

  • Test with remote control
  • Test using MAVLink ground station
  • Test using ROS


Things to know

Before controlling Gapter in any mode you must know the flight modes and its respective positions in RC. We have configured 6 modes to control Gapter. Two modes are dedicated for manual mode and land mode. Rest of them is used for automatic positioning and guiding Gapter. Flight modes are as follows

POSHOLD Mode     position 1
Alt_Hold Mode    position 2
GUIDED Mode      position 3
STABILIZE Mode   position 4
LOITER Mode      position 5
Land Mode        position 6

Positions in RC

The 6 positions of flight modes can be attained by the combination of two switches on top right corner of RC where we can name the last switch as “a” which has only two positions (up & down) before to last switch as “b” which has three positions (up, middle and down). Now positions are as follows:


position1: a(down) & b(up) POSHOLD Mode


position2: a(up) & b(up) Alt_Hold Mode


position3: a(down)& b(middle) GUIDED Mode


position4: a(up) & b(middle) STABILIZE Mode


position5: a(down)& b(down) LOITER Mode


position6: a(up) & b(down) Land Mode


You can find two joystick controllers on RC, one is left “J1”and the other is on right “J2”. “J1” is to control throttle of motors & yaw moment of Gapter. Where as “J2” is used to control pitch(forward&backward) and roll(left and right) of Gapter

Testing Gapter

To control Gapter follow these steps:

After turning ON Gapter you can find a safety switch in red color which starts blinking with beep sounds.

Press and hold safety switch until it stops blinking which turns to solid red and stops beep sound.

You can notice notification LED either in solid blue or green in color. Solid green states Gapter is positioned with gps.

Turn on RC. Make sure throttle must be completely down and all the switches must be in up position. You have to notice Tx and Rx signal on RC screen. It even shows the battery level of Gapter at Rx and RC at Tx respectively.


RC initial position


TX=RC’s battery level

RX=Gapter’s battery level

When you set RC switches , you might have noticed switches “a” & “b” are in up position which Gapter is in Alt_Hold mode.

Now to initialize Gapter, hold J1 stick down right corner. You can notice propellers must be running.

Slowly rise throttle upwards. While doing so Gapter will be flying now. Depending on rise of throttle, Gapter’s altitude will be increasing.

Hold at one position and control J2 stick up, down, left and right for Gapter’s forward, backward, left and right movements respectively

To control yaw movement of Gapter, move J1 stick left and right at its position. Now to land Gapter Keep switches in position 6 (land mode). Gapter will land automatically to its current position.


While changing modes from Alt_hold to stabilize be careful as throttle rises suddenly and Gapter will fly at a huge altitude.While operating throttle (J1 stick) be very careful as single point increment tends to change altitude at high rate.