Quadcopter Setup

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Quadcopter Instructions Rev 0.91 (beta)

Steps:

1) Go to the File menu on the top left, and select “Reset to Quad Setup”.

2) On the Control tab, select your Radio Input type, and the channels to use for cyclic (aileron/elevator) and Tail (rudder) gain/banks-switch. Then bind your radio Tx and Rx.

3) Note that the Collective (pitch) channel of your radio controls collective-throttle. We recommend setting up your radio’s idle-up switch as a safety and setup-switch.

To do this, set the “Normal” pitch-curve in your radio to have a flat line at 0%. Then set the Stunt -1 pitch-curve for a 0 to 75% linear curve, and set the Stunt-2 curve to a 0-100% linear curve.

The “normal” position is then power cut-off, Stunt-1 is flight mode, and Stunt-2 can be used to set up your Quad’s ESCs. The purpose of a 0-75% curve in Stunt-1 for normal flight is to ensure the SK720 has some power left to keep the Quad under control via differential thrust.

4) Set your radio’s idle-up switch to Stunt-2, go to the Utility menu, and click “Set Control Stick Scaling”. Follow the instructions in the short wizard, then double-check that the “Inputs from Receiver” fields respond correctly to stick movements.

5) Set the endpoints on the cyclic and tail gain channels in your radio so you get about 35% in the “cyclic gain” and “tail gain” fields under “Inputs from Receiver”, with the gain-channel switches in both directions. Notice that switching the gain channel changes which cyclic and/or tail bank is in use, marked by a blue bar. By default, the Sk720’s cyclic 1 bank is normal non-self-levelling, and the cyclic-2 bank is self-levelling.

800px-Quad 90 45.jpg

6) Decide whether you want to fly the quad with one rotor arm as “forward”, or in 45-degree mode, as shown in the diagrams below, and mount the unit accordingly. Notice that one side of unit must be mounted square with the direction of flight.

7) On the Control tab, set the Orientation of the unit according to which way the servo bus is pointing on the quad vs forward.

8) Carefully check that the Gyro Motion fields turn green for nose-up and right roll.

9) If the Quad will be flown in 45-degree mode, go to the Swash tab and set the Phasing to +45 degrees.

10) Connect the Quad’s ESC’s (speed controls) to the SK720’s ports, as mapped out in the diagrams above.

11) We recommend keeping the default Servo Tab settings with the travel range of +100% to -110%.

12) Set the RX signal lost failsafes. Set the throttle to around 25%, and in the Utility menu, click set failsafe control positions. If desired, you can also set an SK720 to self level if the RX signal is lost by checking the "Self Level if Signal Lost" button in the Control tab.

13) The last setup step is optional, setting the throttle range of the Quad’s ESCs. If you need to do that, notice first that the ESC outputs are disabled when the SK720 is in setup mode for safety. They are also left disabled until the SK720 sees a radio receiver signal.

To ensure you get a full and equal 0-100% output range when setting your ESC’s throttle ranges, first set the Sk720’s active cyclic and tail bank gains to be Locked to 0% in the setup software, on the cyclic and tail setting tabs. It’s important to do this by the “lock gains” feature because the gain-channel option via the radio will not allow gains below 15%. You can then put the SK720 in to flight mode by removing the USB cable, and program your ESC’s throttle range in stunt-2 mode.

BE SURE to disable the gain-locks or set them to a good value before trying to fly!

14) Do a gentle spin-up to be sure the props go in the right direction. If they don't, swap any two ESC wires on a rotor to reverse, and swap props. If the yaw response turns out to be reversed, you can flip it using the Reverse toggle on the Tail Servo tab in the setup software.

15) The Quad should now be ready to fly. Note that 35% gains are just a good starting point, feel free to increase the gains until you start to get oscillation (then reduce them by a few %).

Troubshooting
Issue:
Quadcopter flips during takeoff.
Solution:
Motors are connected incorrectly. Double check ESC connections to the SK540/720

Issue:
Quadcopter has uncommanded rudder movement.
Solution:
Propeller directions are incorrect. The two propellers furthest from each other should be moving in the same direction, while props nearest to each other should be moving in opposite directions.


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