1. The problem statement, all variables and given/known data basically I am doing work that requires me to calculate power for given thrust of a fan which is hovering. 2. Relevant equations We are given the diameter: 0.8m, thrust output of fan: 250kg, rho=1.1455 kg/m^3, and eta which is the fan efficiency = 0.8 3. The attempt at a solution I found this equation in wikipedia: P^2 = (T^3) / ( (eta^2)(rho)A) using this equation I got 7322w of power to attain a thrust of 250kg...This seems a little off. What is wrong here? does anyone know if this is even the correct value or even correct equation? thank you and appreciate it!