# Can carrier-based aircraft takeoff while the carrier is stationary?

Reading about aircraft carrier operation turns out that carrier operation relies a lot on catapult and carrier itself turns into wind with high rev on propellers. This generate as high wind speed as possible to make a takeoff easier for fixed wing aircraft.

My question is in the absense of carrier's own speed and turning into the wind, would fixed-wing carrier-based aircraft be able to takeoff using catapult and its power alone?

• If they don't carry a full load of ordnance and fuel, why not? Adjust the minimum speed appropriately by reducing take-off mass, and you can take off with the catapult, but without headwind. – Peter Kämpf Jul 15 '15 at 7:38
• If the carrier can't turn into the wind, this certainly depends entirely on the wind speed and direction. – JulianHzg Jul 15 '15 at 10:55
• Perhaps the carrier will at the very least need to maneuver to face into the wind. I can't see a fighter landing or taking off in a crosswind very easily (relatively narrow wheel separation on main landing gear). – ALAN WARD Jul 15 '15 at 22:19

Aircraft carriers using STOBAR (the skyramp) always need to maintain a speed of about 55kmph in order for the Aircrafts on them to take off. This is done to generate enough windspeed on the deck to assist the aircraft to take off. And STOBAR system already hampers the carrying capacity of aircraft, so for takeoff from a STOBAR carrier at rest, a further reduction in Takeoff weight of the aircraft would be required to generate enough lift for the aircraft to take off at such low speeds. This reduction in weight would depend on the Aircraft carrier and the aircraft as such and might create scenarios where this is entirely not possible.

For Aircraft Carriers equipped with CATOBAR, the conventional steam piston drive which is used to catapult the aircraft provides approximately 95 MegaJoules of energy to accelerate the aircraft to speeds where it can takeoff safely. Hence the arguments stated about the STOBAR carriers can be sequentially applied to this class as well. But recent Electromagnetic Aircraft Launch System provides around 122 MegaJoules of energy to accelerate the aircraft. Given the extra amount of energy available to accelerate the aircraft at higher speeds, it is quite possible that it is going to be easier for the Aircraft to take off from a static aircraft carrier equipped with electromagnetic catapults when compared to the aircraft carriers equipped with convention steam piston catapults. But the exact details for the feasibility of this idea would be a matter of national interest and might not be available online.

Also, one should not ignore the extra amount of stresses that an aircraft would have to face while taking off from a stationary aircraft carrier as it would have to accelerate to a higher speed at the same available length of the runway and hence this might prove determinant to the lifetime of the aircraft.

Edit:

Under research technologies such as Ground Carriers, if implemented would also assist further in reducing the weight of the aircraft and hence make it easier for the aircraft to take off from carriers at much lower speeds.

• Given the extra amount of energy available to accelerate the aircraft at higher speeds, it is quite possible that it is going to be easier for the Aircraft to take off from a static aircraft carrier equipped with electromagnetic catapults  -- Pilots (and equipment) don't like sudden changes in velocity that much. I'm pretty sure it will be possible, but SOP will probably still be steaming into the wind to reduce the acceleration required to reach a flying airspeed. – voretaq7 Jul 15 '15 at 19:29
• "Aircraft carriers using STOBAR (the skyramp) always need to maintain a speed of about 55kmph in order for the Aircrafts on them to take off." That doesn't seem to be true. The British Invincible class carriers had a maximum speed of around 52kph and used STOVL. That would leave the carrier unable to launch aircraft if it couldn't reach its maximum speed. – David Richerby Jul 15 '15 at 19:33
• @DavidRicherby I think Victor's statement refers primarily to conventional aircraft using the "ski jump"; The Russian Navy launches Su-33s this way, and the Indian Navy has a few skyramp launchers for the HAL Tejas. When using STOVL aircraft and a skyramp like the Sea Harriers aboard the Invincible, you don't need as much airspeed because you're using thrust for lift. Those Harriers could, in an emergency, do a pure vertical takeoff, but that uses a lot more fuel and has a lighter MTOW so they prefer the ramp (which works for a Harrier even when the carrier is at idle). – KeithS Jul 22 '15 at 16:17

Carrier takeoffs depend on three factors to establish aircraft airspeed. Wind velocity (means speed and direction), aircraft speed, and ship speed. That is why most carriers are travelling into the wind at 35 mph or more. If a catapult developed 150 mph speed, and the wind speed is 10 mph, and the ship is heading into the wind at 10 mph, an aircraft with a 170 mph go/ no go threshold would be pushing the envelope. This is why most carriers like a 20 to 30 knot bow wind over the deck. It makes take offs possible and landings far easier.

In theory, a 20 knot wind properly aligned and 150 mph catapult could launch some fixed wing aircraft.