Hi Bill,
The directions suck, unless of course you speak fluent German. The book doesn't actually tell you, you have to look at the plans and then measure. Ok, here goes. 3 and 7/8 inches from the leading edge. The book also says the all up weight should be 3 lbs, 6 1/2 ozs. It also says that it should run a Mabuchi 550 motor with an on/off switch and Nicads or a gas motor tho it doesn't say what size.
Anything else you need, just ask and I'll try to help. Maybe one of these planes will see the sky. I'll unpack mine and weigh it. I'll bet it's over the book's weight.