Catapults | Catapulting Ahead; Electromagnetic launchers: Hurling objects with electrical energy is giving the catapult a new lease of life.
www.economist.com/news/technolog ... rical-energy-giving
Note:
(a) "Steam became a favourite with naval architects because it was on tap, generated by the engines of ships. Now catapults are going electronic and finding new military and civilian roles. Despite their punch, the steam-driven catapults on aircraft-carriers are not as powerful as some would like. Even with their engines roaring, catapulted aircraft still need the extra airspeed provided by turning the carrier into a headwind. If there is no wind, you must 'crank the ship up' to generate one by sailing faster, says a retired commander of a US Navy warship."
(i) tap
www.merriam-webster.com/dictionary/tap
("on tap")
(ii) punch (n):
"2: a quick blow with or as if with the fist
3: effective energy or forcefulness <a story that packs a punch> <political punch>"
www.merriam-webster.com/dictionary/punch
(b) "The US Navy is so impressed with the push delivered by its new catapult, the Electromagnetic Aircraft Launch System (EMALS), that its next aircraft-carrier, the Gerald R Ford, is in effect being built around it, says Captain James Donnelly, manager of the launcher. EMALS can accelerate a heavy warplane to 180 knots (333kph)—about 30 knots faster than a steam catapult. As the acceleration can be finely adjusted every millisecond, it produces smoother launches, which are better for pilots and aircraft.
The system is being fine-tuned by General Atomics, a defence contractor, at an airfield in Lakehurst, New Jersey. Just under the runway lies a nearly 100-metre array of electromagnets straddled by a sliding, conductive armature. Precisely timed pulses of electricity create a wave of magnetism which rapidly pushes the armature along. The armature is connected to a shuttle on the runway above, to which the aircraft’s nose wheel is hitched."
(i) Lakehurst, New Jersey
en.wikipedia.org/wiki/Lakehurst,_New_Jersey
(ii) amature (n): "the movable part of an electromagnetic device (as a loudspeaker)"
www.merriam-webster.com/dictionary/armature
(c) "The technology is similar to the linear-induction motors employed in some high-speed trains—except, of course, trains are not expected to take off. The Lakehurst system can propel the shuttle to the other end of the runway in just 2.4 seconds, says Mike Doyle, the programme’s chief technology officer. But it takes a lot of energy, more even than a nuclear-powered aircraft-carrier can suddenly muster. Hence energy is stored kinetically in rapidly spinning rotors and released to power generators whenever the catapult is fired. Such kit is not cheap. The four-catapult system for the Gerald R. Ford has a price tag of some $750m. But it eliminates all the tentacular plumbing of steam catapults and should cut crewing and upkeep expenses by about $250m over its expected 50-year life, the retired commander estimates. Being much lighter it will also make the aircraft-carrier more stable, manoeuvrable and cheaper to propel. EMALS is costly partly because it has to be squeezed into the confines of an aircraft-carrier. Building such a system on land would be much cheaper. * * * The aircraft, of course, would also have to land on these shorter runways. Cables are used to catch a tail-hook on planes landing on carriers. Something similar could be employed on runways; arresting cables are already used on short runways at some military airbases. * * * The energy captured by the cables could be stored and reused for catapult launches, suggests Mr Champion."
A linear induction motor (LIM) is a type of "induction motors but is very typically designed to directly produce motion in a straight line." Wikipedia
(I do not know what it exactly means. So I will stop here.)
(d) "Catapults are also making a comeback as a way to launch projectiles and missiles. Some naval missiles are ejected with a burst of pressurised gas or a small booster charge before the rocket in the missile ignites. This reduces the risk of a warhead detonating in the launch tube. Launchers using linear-induction motors coiled inside a tube have been developed, but these coilguns showed mixed results."
Watch only animation in
coilgun
en.wikipedia.org/wiki/Coilgun
(a type of projectile accelerator consisting of one or more coils used as electromagnets in the configuration of a linear motor)
(e) Separately: "A railgun is an electrically powered electromagnetic projectile launcher" Wikipedia
(f) "there are plenty of down-to-earth ideas about what to do with electromagnetic catapults. Elon Musk, the billionaire founder of PayPal, Tesla Motors and SpaceX, has proposed using them to propel passenger pods at more than 1,200kph along an elevated track between Los Angeles and San Francisco. More prosaically, IAP Research, a technology-development company based in Dayton, Ohio, has come up with something for the handyman. With funding from a toolmaker it has produced a prototype electromagnetic gun that drives nails into concrete. Dave Bauer, the firm’s founder, expects it to be in hardware stores within a couple of years."
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