Heewing F01 balance

I’m building a Heewing F01 using a Holybro Kakute F405-Wing Mini and some spare parts. It’s an interesting build as the baseline has moved on since I first brought my RC equipment and, for example, the autopilot does not support PPM but only serial based protocols such as SBUS. My transmitter is old enough that getting a FASST receiver with SBUS is hard. Luckily one (and only one) of my stash of recievers supports that.

For batteries, I have both 3S 2200 mAh 110 mm and 2S 1300 mAh 75 mm long batteries. Neither is great - the 3S is likely too heavy, and the CoG is too far back with the 2S.

For reference, the math is:

• Distance from design CoG to back to front of battery area: ~130 mm
• 3S battery: 110 mm long at 184 g
• 2S battery: 75 mm long at 77 g, need two to balance

The 3S has a moment of (130 - 110/2)*184 = ~14.2e3, while the pair of 2S gives (130 - 75/2)*75*2 = ~13.8e3. So it’s nice to see the math match reality.

Heewing recommend 2-4S 1500-3500 mAh (!) and recommend a 3500 mAh 85x40x40 246 g. AUW is 350 g to 850 g, and my current build is 311 g.

So a SWAYTRONIC 3S 1600 mAh 87x43x22 or 2400 mAh should be fine.