How Can Thrust Be Expressed in Newtons for an Engine Rated at 160 HP?

[simurq]

Given that an engine's rated power is 160 HP (~119kW), how can I express thrust (T) in Newtons, if aerodynamic drag (D) requires weight expressed in Newtons as well to ensure consistency when calculating power available (Pa) and power required (Pr)?:

D = (\frac{1}{2}\rho SC_{D})V^{2}+\frac{2W^2}{\rho S\pi AV^2}

where:

\rho = density at given altitude, \frac{kg}{m^3}
S = wing area, m^2
C_{D} = zero-lift coefficient of drag
V = true airspeed, \frac{m}{s}
A = wing aspect ratio

I want to solve the equation for excess power: P_{ex} = P_{a} - P_{r} = TV - DV

Thank you!

Rustam

 

[OldEngr63]

Power is expressed by the relation
P = F * V
where
P is power,
F is force (thrust, drag, etc)
V is velocity (speed)

 

[cjl]

Rather than changing the thrust to Newtons, why don't you convert the drag force to a power required value? You can do that with the equation mentioned by OldEngr63 above - knowing the drag force at any given speed, you can calculate the power required for level flight. Power available won't be the engine power though, which will complicate things - if you want an accurate result, you should also account for propeller efficiency.