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Basic diagram of an onager, a type of catapult. A catapult is a ballistic device used to launch a projectile a great distance without the aid of gunpowder or other propellants – particularly various types of ancient and medieval siege engines. [1] A catapult uses the sudden release of stored potential energy to propel its payload.
With up to 121 megajoules available, each one of the four disk alternators in the EMALS system can deliver 29% more energy than a steam catapult's approximately 95 MJ. [8] The EMALS, with their planned 90% power conversion efficiency, will also be more efficient than steam catapults, which achieve only a 5% efficiency. [6]
A mass driver or electromagnetic catapult is a proposed method of non-rocket spacelaunch which would use a linear motor to accelerate and catapult payloads up to high speeds. Existing and proposed mass drivers use coils of wire energized by electricity to make electromagnets , though a rotary mass driver has also been proposed. [ 1 ]
There are various types of potential energy, each associated with a particular type of force. For example, the work of an elastic force is called elastic potential energy; work of the gravitational force is called gravitational potential energy; work of the Coulomb force is called electric potential energy; work of the strong nuclear force or weak nuclear force acting on the baryon charge is ...
The depth of the potential well depends on the vehicle's position, and the energy depends on the vehicle's speed. If the kinetic energy exceeds the potential energy then escape occurs. At the Earth's surface this occurs at a speed of 11.2 km/s (25,000 mph), but in practice a much higher speed is needed due to airdrag.
An electromagnetic catapult, also called EMALS ("electromagnetic aircraft launch system") after the specific US system, is a type of aircraft launching system. Currently, only the United States and China have successfully developed it, and it is installed on the Gerald R. Ford -class aircraft carriers and the Chinese aircraft carrier Fujian .
The floating arm trebuchet uses a counterweight held on top of a tall drop channel to transfer potential energy into kinetic energy. [5] A projectile is loaded into a sling at the end of the throwing arm. Upon releasing the trigger, the counterweight is allowed to drop through the channel. [2]
The technique to do this uses the Oberth effect, where releasing the payload when the tether is moving with higher linear speed, lower in a gravitational potential gives more specific energy, and ultimately more speed than the energy lost picking up the payload at a higher gravitational potential, even if the rotation rate is the same.