Bell AH-1Z Viper, a twin-engine attack helicopter, has the tail rotor configuration. The helicopter propulsion system consists of two General Electric T700-GE-410 turboshaft engines which can develop 1,800hp each at standard Sea Level. The helicopter rotor diameter is 14.6m and a fully-loaded helicopter weighs 8,390kg. Assume the engine power is proportional to density ratio, i.e. 

For the condition of: 

r

mechanical efficiency of 0.95, measure of merit equal to propeller efficiency and equal to 0.75, Oswald efficiency factor of 0.7, and = 0.4, calculate: 

a) The helicopter maximum flight ceiling at a temperature of 15°C. Note: assume temperature does not change with altitude. 

b) The helicopter maximum cruise velocity at an altitude of 2000m and a temperature of 10°C. Note: The nonlinear equation in this section can be solved graphically and an approximate value is acceptable.

 

Pn=Pog.