The problem is still not solved.

I did the upgrade to the latest version of the FlightCtrl Firmware, but the problem remains. An addicional problem is the lifetime of the battery. After 10 minutes the battery must be recharged which takes about 2 hours, so I need to buy another battery for making longer tests.

A lot of problems.

After some tests in open space, I have seen that the movements of the "quadcopter" become very unstable as after sometime it tends to yaw to the left. I have tried several times to calibrate the "quadcopter", but without success. I have checked again all the components to see if could find any trouble. I have also checked that all the data provided by the MikroKopter-Tool were within the expected values but everything was fine. The next step is to upgrade the Firmware of FlightCtrl to the latest version.

Finally the new quadcopter is ready for a test drive.

Figure 1

Finally all the electronic components and brushless motors from the old "quadcopter" were re-mounted in a new frame (Figure 1).

Figure 2

To avoid always be re-weld the connections whenever a change is made the connections between the brushless motor controllers and the motors/Flight-Ctrl were connected with connectors with protective plastic material (Figure 2).

Figure 3

Figure 3 shows another detail of the "quadcopter". The Lipo battery is placed under the center box and fixed with "Velcro" strips.

Figure 4

Figure 4 shows a view from above.

The new frame is almost finished.

The new frame is almost finished. I have already removed the electronic components and brushless motors from the old frame and I'm assembling them in the new frame. The corners were connected and glued using the plastic ferrules (4 mm in diameter) used in the cables of bicycles. I have used the brand glue "Nural Pattex 92" to repair the plastic. This is bought in two tubes to be mixed each other and it takes four hours to get harden. The motor mounts were made from aluminum plates and rubber tube. The "landing gears" were made from the polyethylene foam tubes. The center box was made from PVC profiles and panels.