Originally Posted by
Maximilionalpha
Here's one more and it's 99% accurate...Have someone to walk with your plane in hand, across an open field and for every 50 feet, snap a photo of what the plane looks like at that distance, up until they've counted off a couple hundred feet. Once you know what your plane looks like at that distance, then you'll know when it's at, or above that distance, in the air.
Yes, a .40 to .60 sized RC plane casts a man sized silouette and at 400 feet you can easily see the physical differences between most men and most women.