Inside a Jet Engine: teacher key

Airplanes, grade 6 edition, written for 6th grade. What pushes a plane through the air? Follow the air through a jet engine, learn why turbofans are fuel-efficient, and see how fast flying grew from the first short hop in 1903.

Read the book. Print this page for the key.

Questions and answers

1. What does the compressor do in a jet engine?
   • It squeezes the air to a much higher pressure (answer)
   • It steers the plane
   • It carries the fuel
2. What makes thrust in a jet engine?
   • The gas leaving the nozzle is faster than the air entering (answer)
   • The gas stays in the engine
   • The air stops at the turbine
3. What is the ratio of the two air streams in a turbofan called?
   • The inlet ratio
   • The bypass ratio (answer)
   • The lift ratio
4. Which kind of plane do propellers suit?
   • Slower planes (answer)
   • The fastest planes
   • Planes with no wings
5. What happens to lift when a plane flies faster?
   • It shrinks
   • It grows with the square of the plane's speed (answer)
   • It stops
6. How long did the Flyer III flight in 1905 last?
   • 39 minutes (answer)
   • 12 seconds
   • 25 hours

Words

• compressor: air squeezer
• turbine: spinning engine part
• nozzle: exhaust opening
• turbofan: engine with fan
• inlet: front opening