Hej,

I have managed to break the AIO board on my 4" Rotorama build unfortunately. As I have modified the arms by hand-drilled 9 mm hole circle motor mounting holes, which haven't been done nicely I have decided to retire that build. By drilling the 9 mm hole circle holes I have weakened the arms so much that it hasn't felt stable. Entirely my user error. The AIO board has died prematurely when I have tried to rewire it from rather thin wires and XT30 to 14-gauge and XT60. The board has suffered from internal short, could measure continuity between parts that shouldn't be shorted.... :-(

To salvage the parts still working fine I have started to look for a frame in the size 3,5-4", which could take natively the FPV Cycle 16 mm motors (being 1606 size) and preferable either a 30,5 mm stack or perhaps an AIO.
During the search I have abandonned the AIO path, since if I damage anything on an AIO I can probably scrap the entire card. So either 20 mm or 30,5 mm stack...

After looking through a lot of different designs on CNC Madness and other portals I have opted for the AOS 3.5 frame. The latest iteration called O3 seemed like an interesting proposition. When I have dicovered that you can get it in different colours I have stopped searching :-)

Have been contemplating between SpeedyBee F7 mini stack and the Diatone Mamba F405 Basic Mini Mk IV stack. Took the latter due to availability in EU, since I am located in Sweden.

I have purchased a camera for a project that I have never managed to build, a Foxeer T-Rex 1500 TVL camera. This has not many reviews, but the few available have convinced me, that I need to try it out. Did not disappoint, amazing camera.

The motors were given, FPV Cycle 16 mm white ones. Unfortunately the wires have been cut just a bit too short for the FETtec 35A AIO board on the 4" build. 2 motors could have been used with the remaining wires, but the 2 ones for the back arms needed a bit of an extension. I have looked at TinyLED racewire options, but they have looked a bit crazy on the AOS arms and I felt a bit uncomfortable to cut the wires so close to the motors. So I have decided to extend the wires.

I am not a master in soldering, but I can do simple stuff. So I have decided to use 20 AWG battery wires as extension. The original white wires on FPV Cycle motors are 24 AWG, this size I haven't got at home. So 20 AWG it is. By using my Omnifixo soldering help tool I could align the wires very precisely and could secure the nice and stable solder joint. Have used 2 layers of shrink tube to protect the solder from flexing fatigue and could extend the wires. I think it has come out pretty nicely, you can see the pictures later.

I have a TBS Triumph stubby antenna for the VTX from the 4" build, had to construct an antenna bracket for that one. Have carried over the Sixty9 Crossfire from the 4" build, which has been located on the aft 20x20 location on the chassis. The normal sized Immortal-T antenna could sit underneath the front, zip-tied it to the arms. I haven't studied the link quality yet on distance, but if it manages with my usual maximum 500 meters of distance I would be happy.

Dry weight 188 grams. With 1404 motors probably 12-15 grams lighter, but I love the FPV Cycle 16 mm ones so much that they have been a no-brainer...

Have done a short maiden test, goes pretty well. Since the maiden I have sorted out the missing link quality, raised the camera angle and have ordered more 850 mAh packs :-)

Maiden: