It was already determined that the jet velocity of this engine is 376 metres per second. Suppose that this Boeing 777 flies at 11 kilometres at M=0.82, what is then the jet efficiency of this engine (in percent)?

Answer 1

To find the jet efficiency, we need to calculate the actual velocity of the jet.

Given:
Speed of sound at sea level (Mach 1) = 343 meters per second

We are told that the Boeing 777 flies at M=0.82, which means:

Actual velocity of the aircraft = M * Speed of sound
= 0.82 * 343 m/s
= 281.26 m/s (approx.)

Now, the efficiency of the jet engine is given by the formula:

Jet efficiency (%) = (Actual velocity / Jet velocity) * 100

Plugging in the values, we get:

Jet efficiency (%) = (281.26 / 376) * 100
= 74.77% (approx.)

Therefore, the jet efficiency of this engine is approximately 74.77%.