Question

For maximum propulsive efficiency it is nearly always desirable to accelerate ________ mass across a _________ velocity difference. (max/min)

Answer 1

For maximum propulsive efficiency it is nearly always desirable to accelerate Maximum mass across a Minimum velocity difference.

Propulsive Efficiency Ƞ_p is the ratio of the Thrust work to the Engine work. Mathematically Simplified,

From the above equation it can be seen that Propulsive Efficiency depends upon the exit velocity V_e and the aircraft velocity V_0. When the difference is minimum Propulsive Efficiency will be high. At the same time mass flow rate (m₀) must be high since the Thrust Work = m₀( V_e-V_0.)

answered by: anonymous