Sec. 59.n PROPULSION-DEVICE PERFORMANCE 353 



Qz{(l) is the torque per blade at the angle Q The mean thrust is 



F zifi) is the transverse tangential force per blade 2, 



at the angle %. Then 7'M„a„ = tt f T{Q) dQ 



^T Jo 



Tzid) = I T{x' , e) dx' Similarly, letting the total torque for all blades at 



'^"'' any one blade angle be Qi6), then 



7, / dx' and 



Hx 



1 r^"' 



If the total thrust for all blades at one blade Qivipan = TT 1 ^^^) '^^ 



angle is designated as T{B), then '"' " 



z / 2 '\ Setting [F{d)]^. equal to the total horizontal 



Ti^) = Zl ^z( ^ + -^1 transverse force of all blades at any one blade 



"' angle, and [F{e)], equal to the total vertical 



For a 4-bladed propeller, where Z = 4, the fore- transverse force of all blades at any one blade 



going becomes angle, 



ne) = Tz{6 + 2^p) + Tz{e + 2^) [Fie)i = t Fz{e + ^f) cos [e + ^f) 



+ T.(. + ?fl) + Tz{e + f) [Fie)i = t Fz{e + f ) sin {e + f )■ 



