This is the main quad I use to race and practice flying. It is meant to be heavy duty (think bullet proof) at the expense of weight.
I have another build that is virtually identical except for the frame (but frame has same layout and almost same dimension)

Runs on stock betaflight settings and PIDs except for

• 0.8 rate instead of 1.0
• 35 degree cam angle compensation

The electronics supports 6S in theory (and tested) but motor's KV is too high. Considering the of the overall build, 4S is the only realistic option. Right now, after a heavy flight session, ESC, motors and battery are equally warm to the touch, which indicate its a somewhat balanced build in term of weight/motor/battery/esc-rating.

This is such a heavy duty build that my main problem now is that parts are wearing down. The frame itself is also wearing down because of all the crashes and scraping on hard surface (concrete, parvement). Also had quite a few solder point breaking because of vibration and crashes. Have to put liquid tape on all solder joins as a stress relief or else they start randomly breaking after 40 to 50 packs.

RS2205S are pretty bad unless you fix them. Issues are:

• Bearing wear down pretty fast (makes a terrible sound) (see part list for replacements)
• Bell shaft is weak and bend often
• Bell's magnets come off after a few light crashes. (see part list for glue)
  Had to buy many replacement bell kits and spare motors. Also hapenned that a motor baseplate bended because I had only 2 screws on it... Should always put 4 screws
  To help with the magnets, I now glue them with Loctite 380. 480 is recommended but I couldn't find any at reasonable price. It's like a rubber based crazy glue.

To protect batteries, a thick 2" heatshrink is used. Be careful not to overheat the battery when applying heat to the heatshink tube.

Todo:

• fix LEDs as they got smashed repeatedly by the props and are not working anymore...
• use cut props blade + tape to protect ESCs instead of tie-wrap and heat-shink