How do you determine the speed of an airplane from the ground with nothing more than a stopwatch?
Well never seen that film but technically yes its possible by two methods 1.Two markers on the ground with know distances and then the time taken to cross them will give speed (as Speed is Distance/Time) 2.A more robust based on ESTIMATION principle used in battle field and warfare This is a Tough technique that can be used is adopting triangles principle and some practice. At a time t position yourself at such a place that the Aircraft is at 45 degree (or half way from a flat horizon and overhead ) and then start the stop watch and stop it as soon as it gets overhead.(90 degree or veritical) So here total Angle traversed is 45 degree and you know the approximate height(by estimation) of that aircraft by the size(apparent size or span of the wings will tell the height it is moving at.. a lesson that is given it Anti-Aircraft Gunnery and Aircraft identification and basic rifle ranges) Now if the Vertical Height is know and the angle sub tending to the first point is know using simple ma
