This was shot using altitude hold.
Unfortunately I wasn’t able to go full speed as it was quite windy.
I used the standard transmitter and stood halfway down the 580 meter distance.
The distance and speed are rounded to the nearest 10 for simplicity.
Calculations for average speed:
Distance ÷ Time = Speed
580 ÷ 39 = 33.2 mph (53.5384 kmh)