Hello my whoop friends! The time has come! I can give an official recommendation for the 75mm 802 27k 12A FC Combo. I'll just call it Butterfly75 802 27k. I know it took a long time, but good things take time (and a lot of effort). That's the way it is in life.
The development of this whoop is now complete for now and I am happy to announce that the 75 802 27000kV is my new standard whoop and replaces the 75 802 25000kV for me (and maybe for you too?). 75 802 25k is still a good combo if you build it light (5-6A flight controller and max 22g dry weight). However, 802 25k is not as good in strong winds as 802 27k. And since it's windy here a lot, 802 27k will definitely be my new standard whoop for now. Thanks to 12A ESC and Bluejay 96khz ESC firmware, 75mm 802 27k is now possible with a good efficiency. And thanks to Throttle MID set to 0% and Throttle Expo set to 30%, and low pitch props (gemfan 1608-3) good throttle control is now also possible despite the high kv. (⚠️You need a fast rc protocol for this, such as Spektrum, ELRS, Flysky, Redpine, etc. otherwise the delay accumulates and throttle control becomes more difficult again⚠️)

VIDEOS of this Whoop in Action:
https://www.youtube.com/playlist?list=PLYPR_WgF4mzWibXoZYNmJAkquz5sEbFcd

► BUILD LIST | PARTS LIST | MOD`S | Butterfly75 802 27k

● Frame: Happymodel Mobula7 V4 (with some modifications to make it lighter) and some ⚠️mods to fit the X12 FC⚠️ and and battery slot modifications⚠️ to accommodate wider and higher lipos such as dogcom 550mah up to GNB 660mah (⚠️the GNB 550s fit in the original slot!⚠️)
● Canopy: Eachine UZ65 Canopy (with mods to make it lighter or Happymodel Mobula7 Canopy
● Flightcontroller: Happymodel X12 ELRS (out of a Mobula7) ⚠️Motorplugs desoldered and USB Ground shielding removed with a dremel rotary tool and a very tiny diamond milling ball to save about 0.5g of weight (it was not an easy task! not for beginners!)⚠️
● Motors: RCinpower 802 27000kV ⚠️direct soldered to the FC⚠️ (not easy because of very tiny solder pads) ● Motor Screws: Reny Micro (CHEMIS Type 3 Head) M1.4 x 3.5mm or Titan M1,4 x 3,5mm from aliexpress ● Props: Gemfan 1608-3 (my favorite) or 1610 2-Blade ● Lipo: Tattu/Dogcom/weebleed/tinywhoop 300mah foldet cell (not testet) GNB 1S HV 380mah 90C (Indoor smaller tracks), GNB 1S HV 450mah 80C, Tattu/Weebleed 450mah foldet cell, GNB 1S HV 530mah 90C, GNB 1S HV 550mah 100C, DOGCOM 1S 550mah 150C, GNB 1S HV 660mah 90C ● Main Plug: ⚠️BT2.0 / A30⚠️ ● Main Cable: ⚠️AWG 20⚠️ ● Video Transmitter: on the board ● Cam: Runcam Nano3 (one of the newer ones) ● Dry Weight: Around 24g ● All up Weight: From around 34g up to around 40g ● PID Tune: Stock BF 4.4.0 PIDs (⚠️Idle Speed set to 12%, Throttle Boost set to 0, Throttle MID set to 0% and Throttle Expo to 30%⚠️)
● Rates: Betaflight Rates 800 Degrees on all axes
● Flightcontroller Firmware: BF 4.4.0
● ESC Firmware and Settings: ⚠️Bluejay 19.2 96khz, Both, Startup Power Boost and Startup Power Protection set to Maximum, Motortiming set to Low⚠️
● Flight Time: From 2:00min up to 4:00min in racing and rage whooping and max. 5:30min Cruise flight with a good fresh 450mah Lipo (down to 3.3V+ after recovery)
● Flight Mode: Air Mode outdoor and Acro Mode Indoor

► ENCOUNTERED PROBLEMS

● Flashing ESCs with Bluejay: An ESC was suddenly no longer found. Checking "Ignore inappropriate MCU layout" then solved the problem and I was able to flash the esc again. ● Motors not turning in Betaflight motors tab under reordering motors and also under direction of rotation: They didn't rotate in the motor test either. With 24khz it was no problem but with 48 and 96khz the motors didn't turn. That's why reordering the motors and setting the direction of rotation was a bit difficult and tedious. ● Failing/non-spinning motors: With Bluejay 96khz, the motors only turned with Startup Power Boost and Startup Power Protection set to Maximum. And so that they don't switch off in flight at 0% throttle, I had to increase the idle speed to 12%, which in reality corresponds to an idle speed of 5.5%. Say with bluejay 96khz and 27k motors the standard idle speed value is a bit higher than I was used to. ● ‼️ The motor beeper and the remote control must be switched off when flashing escs! ‼️
● Short flight times/low efficiency: Solved with Bluejay 96khz ESC Firmware and motortiming set to low.
● Difficult throttle control because of the high kv of the motors: Solved with Throttle Boost set to 0, Throttle MID set to 0% and Throttle Expo to 30% and low pitch props (gemfan 1608-3)