, , , . Fn (. 18.10, ) . Fn Ft1, Frl, Fa1.
Fn FaX :
Fl2 = Fat = 2-103 T2/d2, (18.18)
2 , ; d2 .
. 18.10. ,
Fn Fa2 :
' (18.19)
Ft1 = Fa2 = 2* 103 T t /dwt = 2 103 T2 / (uη dwl ),
Τ1 , -; η ; dwi B . Fr1 Fr2 (. 18.10, ):
. Fl2 , Fn , (. 18.10,6).