“In order to ascertain the height of the tree I must be in such a position that the top of the tree is exactly in a line with the top of a measuring-stick—or any straight object would do, such as an umbrella—which I shall secure in an upright position between my feet. Knowing ...
The c/l guys have used the rpm x pitch to get pitch speed calculation for years-and they say it's pretty close. They also have a very accurate method of calculating airspeed- put the handle in a tower- fly the airplane at a set height- and you know the distance its traveling if ...