I’m using this thread to document my MFE Believer setup.
I am saving setup information here and I’ll add to it if anyone asks for additional information.
Airframe: MFE Believer
Motors: 2x KDE 4014XF
ESCs: 2x KDE 35A ESCs
Props: 12x12 APC props, cw & ccw
Batteries: 6S2P 5000 mAh Spektrum Lipos
FC: Speedybee F405 FC running Ardupilot 4.5 Dev (will update to stable soon)
Airspeed Sensor: Matek I2C
GPS: Cheapie, spare 3DR, will be upgrading soon
AUW: 3.78kg
Here’s the eCalc performance analysis:
KDEDirect KDE4014XF-380 (380) & APC Electric E 12 x 12 @ 6S, 10000mAh - eCalc propCalc.pdf (908.9 KB)
Endurance: 1hr flight time, with 25% capacity left on batteries
Here are more specs: https://en.makeflyeasy.com/index.php/believer/
I got mine from Nathan Eick, he has a website, reach out to him at https://www.dualrc.com/ to get an airframe. I understand he was teed off that it was always out of stock and decided to buy a whole container of them! 
He was very helpful in recommending a setup, etc.
Here is my parameter file:
MFE Believer 20240403.param (19.3 KB)
And a bin file from this past Sunday, 3/31 flight, where I got just over 1h flight.
FLIGHT SUMMARY ==================
Sortie 1
Distance traveled: 74511 meters
Max Wind: -999.0 m/s
Flight time: 61.4 mins (3681 sec)
Energy used: 7539 mAh
Max Airspeed: -999.0 m/s
Max Ground Speed: 40.4 m/s
Average Throttle: 49% (Std dev: 8.1%)
Altitude (MSL): 58.0 - 173.0 = 115.0 meters
Voltage range: 21.1 - 24.6 V
Autopilot temperature range: 33.1 - 39.6 deg C
Efficiency (energy/distance): 101 mAh/km
Efficiency (energy/time): 123 mAh/min
Efficiency (distance/time): 1.21 km/min
Flight modes:
TAKEOFF (69 secs)
CRUISE (50 secs)
FBWA (239 secs)
MANUAL (201 secs)
FBWA (8 secs)
LOITER (28 secs)
FBWA (17 secs)
LOITER (3011 secs)
FBWA (57 secs)
Here are some pictures of the plane, flight videos and weight and balancing right on the main spar:
