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35-1044: In 1969, the PLAAF issued an order to build a small, inexpensive, STOL (short takeoff and landing) lightweight fighter in order to replace the MiG-19 . Two designs were submitted, namely the Shenyang J-11 and the Nanchang J-12. Prototypes of the J-12 were designed by Lu Xiaopeng and built by the Nanchang Aircraft Manufacturing Company (NAMC) . The J-12 was a small single-seat jet fighter with low-set, swept wings , swept control surfaces, tubular fuselage, and nose intake with small or absent shock cone and flight testing began on 26 December 1970. Due to less than satisfactory performance, three additional J-12I prototypes were built with improvements such as simplified control surfaces ,

70-467: A 50-foot (15 meters) obstacle within 1,500 feet (450 meters) of commencing takeoff or in landing, to stop within 1,500 feet (450 meters) after passing over a 50-foot (15 meters) obstacle. Also called STOL. STOL (Short Take Off and Landing). STOL performance of an aircraft is the ability of aircraft to take off and clear a 50-foot obstruction in a distance of 1,500 feet from beginning the takeoff run. It must also be able to stop within 1,500 feet after crossing

105-443: A 50-foot obstacle on landing. An aircraft that, at some weight within its approved operating weight, is capable of operating from a STOL runway in compliance with the applicable STOL characteristics and airworthiness, operations, noise, and pollution standards" and ""aircraft" means any machine capable of deriving support in the atmosphere A STOL aircraft is an aircraft with a certified performance capability to execute approaches along

140-467: A 50-ft (15-m) obstacle at the end of that distance and upon landing can clear the same obstacle and then land within 1,000 ft. The STOL mode of flight is one during which an airplane taking off or landing is operated at climb-out and approach speeds lower than the conventionally accepted margins of airspeed above the power-off stalling speed of the airplane. Additionally, some aircraft manufacturers market their products as STOL without providing evidence that

175-460: A forward slip, the pilot banks into the wind and applies opposing rudder (e.g., right aileron + left rudder) in order to keep moving towards the target. If you were the target you would see the plane's nose off to one side, a wing off to the other side and tilted down toward you. The pilot must make sure that the plane's nose is low enough to keep airspeed up. However, airframe speed limits such as V A and V FE must be observed. A forward-slip

210-470: A glideslope of 6 degrees or steeper and to execute missed approaches at a climb gradient sufficient to clear a 15:1 missed approach surface at sea level... A STOL runway is one which is specifically designated and marked for STOL aircraft operations, and designed and maintained to specified standards. Heavier-than-air craft that cannot take off and land vertically, but can operate within areas substantially more confined than those normally required by aircraft of

245-402: A landing approach at low power. Without flaps or spoilers it is difficult to increase the steepness of the glide without adding significant speed. This excess speed can cause the aircraft to fly in ground effect for an extended period, perhaps running out of runway. In a forward slip much more drag is created, allowing the pilot to dissipate altitude without increasing airspeed, increasing

280-604: A lighter area ruled fuselage, and revised intake. In 1977 the development of J-12 was abandoned, due to inadequate firepower and engine thrust and also likely due to the introduction of the Chengdu J-7 , which offered superior performance and was based on the Soviet MiG-21 F. In addition, the concept of aerial guerilla warfare was by this time considered to be untenable. The J-12 prototypes had accumulated 61 hours in 135 flights by 1977. In 1990s, Lu Xiaopeng proposed upgrading

315-433: A runway centerline while on approach in a crosswind or be employed in the final moments of a crosswind landing. To commence sideslipping, the pilot rolls the airplane toward the wind to maintain runway centerline position while maintaining heading on the centerline with the rudder. Sideslip causes one main landing gear to touch down first, followed by the second main gear. This allows the wheels to be constantly aligned with

350-432: A wings-level attitude. In fact, in some airplanes stall characteristics may even be improved. Aerodynamically these are identical once established, but they are entered for different reasons and will create different ground tracks and headings relative to those prior to entry. Forward-slip is used to steepen an approach (reduce height) without gaining much airspeed, benefiting from the increased drag. The sideslip moves

385-476: Is a conventional fixed-wing aircraft that has short runway requirements for takeoff and landing . Many STOL-designed aircraft also feature various arrangements for use on airstrips with harsh conditions (such as high altitude or ice). STOL aircraft, including those used in scheduled passenger airline operations, have also been operated from STOLport airfields which feature short runways. Many fixed-wing STOL aircraft are bush planes , though some, like

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420-438: Is a function of the square of the minimum flying speed ( stall speed ), and most design effort is spent on reducing this number. For takeoff , large power/weight ratios and low drag help the plane to accelerate for flight. The landing run is minimized by strong brakes , low landing speed, thrust reversers or spoilers (less common). Overall STOL performance is set by the length of runway needed to land or take off, whichever

455-403: Is a high lateral acceleration and β {\displaystyle \beta } could be a negative value. There are other, specialized circumstances where slips can be useful in aviation. For example, during aerial photography, a slip can lower one side of the aircraft to allow ground photos to be taken through a side window. Pilots will also use a slip to land in icing conditions if

490-459: Is a term used in fluid dynamics and aerodynamics and aviation . It relates to the rotation of the aircraft centerline from the relative wind . In flight dynamics it is given the shorthand notation β {\displaystyle \beta } (beta) and is usually assigned to be "positive" when the relative wind is coming from the right of the nose of the airplane. The sideslip angle β {\displaystyle \beta }

525-674: Is critical, because many small, isolated communities rely on STOL aircraft as their only transportation link to the outside world for passengers or cargo; examples include many communities in the Canadian north and Alaska . Most STOL aircraft can land either on- or off-airport. Typical off-airport landing areas include snow or ice (using skis), fields or gravel riverbanks (often using special fat, low-pressure tundra tires ), and water (using floats ): these areas are often extremely short and obstructed by tall trees or hills. Wheel skis and amphibious floats combine wheels with skis or floats, allowing

560-403: Is especially dangerous if there are nearby obstructions under the climb path and the aircraft is underpowered or heavily loaded. A slip can also be a piloting maneuver where the pilot deliberately enters one type of slip or another. Slips are particularly useful in performing a short field landing over an obstacle (such as trees, or power lines), or to avoid an obstacle (such as a single tree on

595-465: Is essentially the directional angle of attack of the airplane. It is the primary parameter in directional stability considerations. In vehicle dynamics, side slip angle is defined as the angle made by the velocity vector to longitudinal axis of the vehicle at the center of gravity in an instantaneous frame. As the lateral acceleration increases during cornering, the side slip angle decreases. Thus at very high speed turns and small turning radius, there

630-465: Is flying inefficiently. Flying in a slip is aerodynamically inefficient, since the lift-to-drag ratio is reduced. More drag is at play consuming energy but not producing lift. Inexperienced or inattentive pilots will often enter slips unintentionally during turns by failing to coordinate the aircraft with the rudder . Airplanes can readily enter into a slip climbing out from take-off on a windy day. If left unchecked, climb performance will suffer. This

665-436: Is longer. Of equal importance to short ground run is the ability to clear obstacles, such as hills, on both take off and landing. For takeoff, large power/weight ratios and low drag result in a high rate of climb required to clear obstacles. For landing, high drag allows the aeroplane to descend steeply to the runway without building excess speed resulting in a longer ground run. Drag is increased by use of flaps (devices on

700-411: Is used: just enough to stop the change in the heading. In the sideslip condition, the airplane's longitudinal axis remains parallel to the original flightpath, but the airplane no longer flies along that track. The horizontal component of lift is directed toward the low wing, drawing the airplane sideways. This is the still-air, headwind or tailwind scenario. In case of crosswind, the wing is lowered into

735-483: Is useful when a pilot has set up for a landing approach with excessive height or must descend steeply beyond a tree line to touchdown near the runway threshold. Assuming that the plane is properly lined up for the runway, the forward slip will allow the aircraft track to be maintained while steepening the descent without adding excessive airspeed. Since the heading is not aligned with the runway, forward-slip must be removed before touchdown to avoid excessive side loading on

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770-619: The United States that were used for scheduled passenger airline operations but are now no longer in existence. Cruise -efficient short takeoff and landing (CESTOL), is an aircraft with both very short runway requirements and high cruise speeds (greater than Mach 0.8). Many different definitions of STOL have been used by different authorities and nations at various times and for a myriad of regulatory and military purposes. Some accepted definitions of STOL include: short takeoff and landing: ( DOD / NATO ) The ability of an aircraft to clear

805-648: The de Havilland Canada Dash-7 , are designed for use on prepared airstrips; likewise, many STOL aircraft are taildraggers , though there are exceptions like the PAC P-750 XSTOL , the Quest Kodiak , the de Havilland Canada DHC-6 Twin Otter and the Peterson 260SE . Autogyros also have STOL capability, needing a short ground roll to get airborne, but capable of a near-zero ground roll when landing. Runway length requirement

840-411: The J-12's fighter design with a reduced Radar cross-section to make the J-12 stealthy, and suggested a modified J-12 fighter to a carrier based fighter for PLA Navy , but none of the proposals were accepted. Data from Chinese Aircraft:China's aviation industry since 1951 General characteristics Performance Armament STOL A short takeoff and landing ( STOL ) aircraft

875-414: The aircraft meets any accepted definition. Slip (aerodynamic) A slip is an aerodynamic state where an aircraft is moving somewhat sideways as well as forward relative to the oncoming airflow or relative wind . In other words, for a conventional aircraft, the nose will be pointing in the opposite direction to the bank of the wing(s). The aircraft is not in coordinated flight and therefore

910-420: The aircraft sideways (often, only in relation to the wind) where executing a turn would be inadvisable, drag is considered a byproduct. Most pilots like to enter sideslip just before flaring or touching down during a crosswind landing . The forward slip changes the heading of the aircraft away from the down wing, while retaining the original track (flight path over the ground) of the aircraft. To execute

945-497: The angle of descent (glide slope). Forward slips are especially useful when operating pre-1950s training aircraft, aerobatic aircraft such as the Pitts Special or any aircraft with inoperative flaps or spoilers. Often, if an airplane in a slip is made to stall, it displays very little of the yawing tendency that causes a skidding stall to develop into a spin . A stalling airplane in a slip may do little more than tend to roll into

980-467: The choice of landing on snow/water or a prepared runway. A number of aircraft modification companies offer STOL kits for improving short-field performance. A STOLport is an airport designed with STOL operations in mind, normally having a short single runway. STOLports are not common but can be found, for example, at London City Airport in London , United Kingdom . There were also several STOLports in

1015-447: The extended centerline of the runway), and may be practiced as part of emergency landing procedures. These methods are also commonly employed when flying into farmstead or rough country airstrips where the landing strip is short. Pilots need to touch down with ample runway remaining to slow down and stop. There are common situations where a pilot may deliberately enter a slip by using opposite rudder and aileron inputs, most commonly in

1050-437: The front windshield has been entirely iced over—by landing slightly sideways, the pilot is able to see the runway through the aircraft's side window. Slips also play a role in aerobatics and aerial combat . When an aircraft is put into a forward slip with no other changes to the throttle or elevator, the pilot will notice an increased rate of descent (or reduced rate of ascent ). This is usually mostly due to increased drag on

1085-429: The landing gear, and if a cross wind is present an appropriate sideslip may be necessary at touchdown as described below. The sideslip also uses aileron and opposite rudder. In this case it is entered by lowering a wing and applying exactly enough opposite rudder so the airplane does not turn (maintaining the same heading ), while maintaining safe airspeed with pitch or power . Compared to Forward-slip, less rudder

Nanchang J-12 - Misplaced Pages Continue

1120-462: The same size. Derived from short takeoff and landing aircraft. short takeoff and landing aircraft (STOL), heavier-than-air craft, capable of rising from and descending to the ground with only a short length of runway, but incapable of doing so vertically. The precise definition of an STOL aircraft has not been universally agreed upon. However, it has been tentatively defined as an aircraft that upon taking off needs only 1,000 ft (305 m) of runway to clear

1155-515: The track, thus avoiding any side load at touchdown. The sideslip method for crosswind landings is not suitable for long-winged and low-sitting aircraft such as gliders , where instead a crab angle (heading into the wind) is maintained until a moment before touchdown. Aircraft manufacturer Airbus recommends sideslip approach only in low crosswind conditions. The sideslip angle, also called angle of sideslip (AOS, AoS, β {\displaystyle \beta } , Greek letter beta ),

1190-434: The wind, so that the airplane flies the original track. This is the sideslip approach technique used by many pilots in crosswind conditions (sideslip without slipping). The other method of maintaining the desired track is the crab technique: the wings are kept level, but the nose is pointed (part way) into the crosswind, and resulting drift keeps the airplane on track. A sideslip may be used exclusively to remain lined up with

1225-433: The wings) and by a forward slip (causing the aeroplane to fly somewhat sideways through the air to increase drag). Normally, a STOL aircraft will have a large wing for its weight. These wings often use aerodynamic devices like flaps, slots , slats , and vortex generators . Typically, designing an aircraft for excellent STOL performance reduces maximum speed, but does not reduce payload lifting ability. The payload

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