Best rate of climb for a 47 is 39 kts. However you need to climb out at about 45 kts for the first 350 feet to avoid the shaded areas on the height velocity diagram. Assuming he departed into wind the pilot makes an almost 180 degree turn low level. So he would be almost downwind wind the engine stops(if it did stop). So I guess that video is a good demonstration of why we are taught to climb into wind until 500 feet.