What is the efficiency of a jet engine?

The overall efficiency of commercial aircraft engines has been improving at a rate of about 7 percent per decade since 1970 (see Figures 3.3 and 3.4). Today, the overall efficiency of commercial aircraft propulsion is approaching 40 percent.

What is the fuel efficiency of a 747?

According to Boeing’s Web site, the 747 burns approximately 5 gallons of fuel per mile (12 liters per kilometer). This sounds like a tremendously poor miles-per-gallon rating! But consider that a 747 can carry as many as 568 people.

What is the most fuel-efficient airliner?

The most fuel-efficient airline was Norwegian Air Shuttle with 44 pax-km/L (2.27 L/100 km [104 mpg‑US] per passenger), thanks to its fuel-efficient Boeing 787-8, a high 85\% passenger load factor and a high density of 1.36 seat/m2 due to a low 9\% premium seating.

Are jet engines fuel-efficient?

Jet engines are already pretty efficient, but Ihme and team believe they have found a way to more precisely control the ratio of air to fuel inside the combustion chamber — the critical variable that governs emissions, efficiency and safety. (Preheating the air makes it easier to burn.)

What is the fuel efficiency of an aircraft per passenger?

Between 1950 and 2018, efficiency per passenger grew from 0.4 to 8.2 RPK per kg of CO₂. The fuel economy in aircraft is the measure of the transport energy efficiency of aircraft .

Are modern planes more fuel efficient than old planes?

Modern jet aircraft have twice the fuel efficiency of the earliest jet airliners. Late 1950s piston airliners like the Lockheed L-1049 Super Constellation and DC-7 were 1\% to 28\% more energy-intensive than 1990s jet airliners which cruise 40 to 80\% faster.

Why does the efficiency of a jet engine increase with velocity?

Jet engine efficiency increases with velocity because the speed difference between the flight and the exhaust is lower.

How can we reduce the take off weight of an aircraft?

An aircraft weight can be reduced with light-weight materials such as titanium, carbon fiber and other composite plastics if the expense can be recouped over the aircraft’s lifetime. Fuel efficiency gains reduce the fuel carried, reducing the take-off weight for a positive feedback.