Quote:
Originally posted by NY Madman:

Thrust alone is not enough to achieve viable flight. If it were, aircraft carriers would never need their catapults. Without the additional forward motion provided by the catapults, every plane would crash leaving a carrier, regardless of the amount of thrust it's engines put out.
confused

Aircraft carriers use catapults because their runways are exceedingly short.

You're right; lift is as essential as thrust. Lift is created by thrust:
Thrust forces the aircraft forward, generating airflow over an airfoil. When the flow of air is fast enough, enough lift is generated, and the aircraft lifts off.

The catapult aids the F-18 in generating the airspeed necessary to get enough lift to haul the Plastic Bug into flight.
On an aircraft carrier's short flight deck, there is not enough room for the F-18's engines to generate enough thrust and airspeed over the wings to get the F-18 up on its own. So they use a catapult aid.
Same F-18 taking off from Miromar? No problem. Runways are plenty long.

Thrust from jet turbines is not instantaneous. Like any other object accelerating from a dead stop, it takes some runway to reach speed. The catapult helps shorten the time needed by magnifying the force of thrust that can be generated by the F-18's own engines.
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