I Promise that the videos will get better… also need to tune it a bit.
More on the VXS (Stretch version of the VX1) frame: https://downanddirtydrones.com/portfolio/
Drone physics: https://downanddirtydrones.com/drone-physics/
Featured at rotor builds: https://rotorbuilds.com/build/4006
Note 1: OSD speed is in FEET PER SECOND, 174ft/s = 119mph (not sure why altitude is not showing up)
Note 2: Boring video from Mobius Mini – I still have to adjust the angle…
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
Nothing special about the setup, just used physics. Frame weight without battery is 289g. Other equipment:
250mm custom frame
DYS Fire 2300kv 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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