4s 127 MPH Quadcopter with Cobra Champion 2207 2450kv motors00:58

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More on the VX1 frame: https://downanddirtydrones.com/portfolio/
Drone physics: https://downanddirtydrones.com/drone-physics/
Featured at rotor builds: https://rotorbuilds.com/build/4006

PLEASE READ:

Note 1: OSD speed is in FEET PER SECOND, 186ft/s = 127mph (not sure why altitude is not showing up)
Note 2: Boring video from OSD – very poor reception/quality. I chopped down the video quite a bit – it hits 186ft/s about 3-4 seconds into the video.
Note 3: After much research, I have found out that GPS is the most accurate way to determine speed. GPS velocity is based off of Doppler calculations – not change in position. This is why the positional accuracy for the ublox M8N is 2.5m, but the velocity accuracy is 0.05m/s. Not many people realize this and it is the reason many think radar guns are more accurate when all evidence actually points to the contrary. However, in order to get better readings, the GPS (ublox M8N) had to be reconfigured to use the “airborne 2g” dynamic platform model. This is much better suited for quads – I have no idea why Betaflight gps_auto_config sets the dynamic model to “pedestrian” since these things hardly move like a pedestrian. Ublox resources:
https://www.u-blox.com/sites/default/files/NEO-M8-FW3_DataSheet_%28UBX-15031086%29.pdf
https://www.u-blox.com/sites/default/files/products/documents/u-blox8-M8_ReceiverDescrProtSpec_%28UBX-13003221%29_Public.pdf

Luckily, winds were calm which helped to keep the speed reading more honest. Once again, in the distance, there was a person on a powered parachute that can verify (and was enjoying) the calm conditions.

Nothing special about the setup, just used physics. Frame weight was around 47g with an AUW of 475g. Other equipment:
178mm custom frame
Cobra 2207 2450kv motors
Racekraft 5051 props
30A Super Racerbee ESCs
SMC Extreme 4s 1400mah lipo
Betaflight F3 flight controller
Crazepony 700TVL Wide Angle FPV Camera (lens is from an old, broken SJCam)
AKK X1 Vtx
Lemon rx DSMX
Ublox M8N GPS
Eachine EV800
Eachine ProDVR
Spektrum DX6

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    1. John Graboski

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