Who will become the first fixed-wing carrier-based trainer in China has become a concern of netizens. In fact, this problem has been quietly solved-the most suitable trainer for Chinese aircraft carriers is L- 15 of Hongdu Company.
There are few types of trainers that China aviation industry can provide for Chinese aircraft carriers. At present, only Coach 8, Coach 9, FC 1, L- 15 can be selected.
Coach 8 has good low-altitude performance, short take-off and landing distance and good maneuverability in hydraulic model, but its design is too early, without considering the needs of aircraft carrier, and there is insufficient room for modification of aircraft structure and strength. Its single engine and hydraulic flight characteristics are far from the target carrier-based fighter. The possibility of its boarding was ruled out first.
Coach 9 is modified from J-J 7, which has good performance at high altitude and high speed, but poor performance at low altitude and low speed. As an advanced training machine for land-based third-generation fighters, it can still be used. The 歼 7 prototype was originally the "most unsuitable for flying" model, which was difficult for teachers to master. Although the air inlets on both sides and double delta wings have been changed, the improvement of low-altitude and low-speed maneuverability when boarding the ship is limited, so it is difficult to overlook. The land-based runway is two kilometers, and the aircraft carrier landing runway is only one hundred meters. The plane should board the ship with its head up. Coach No.9 can't see the runway in the front and rear seats. Flying with his feelings is very risky. Similarly, its single engine and hydraulic flight characteristics are far from the target carrier-based fighter, so the trained pilots have to undergo long-term modification training of two-seat target aircraft, which wastes a lot of time and money.
L- 15 was originally designed as two seats in series. The rear seat is 30cm higher than the front seat. Compared with single-seat fighter, the rear seat has a good field of vision, reaching 6, and the front seat reaches 16, which is an advanced level in domestic and foreign trainers. China is inexperienced in using aircraft carriers, and an aircraft with a good view can greatly reduce the accident rate.
L- 15 is a specially developed trainer with low price (compared with fighter), long overall life, short range and frequent take-off and landing. As the saying goes, it is "real".
In the early 1990s, China introduced three generations of Soviet-made 27SK from Russia, and China Air Force was equipped with new equipment. However, we also found that long-term use of Su-27UB by two-seater pilots is harmful to health, while Su-27SK/ Su-27UB is designed as a large-scale combat consumable, with a service life of only about 3,000 hours. It is a great waste to be used as a trainer for short-distance flight training with frequent take-off and landing. After we introduced the equipment Su -27, we had a lesson of excessive consumption of precious flying life.
To put it bluntly, the aircraft carrier is a high-risk airport, small and wobbly above the sea. All countries in the world crashed during boarding. It is undoubtedly inappropriate to rashly use the two-seat carrier-based fighter as an advanced trainer for on-board risk training. The amount of take-off and landing and basic subject training required by aircraft carrier pilots is far more than that of air force pilots. If you use an expensive two-seat fighter for training, the cost is too high. It is worth pointing out that the landing mode of land-based aircraft is very different from that of aircraft carriers. Land-based aircraft take off on their own on a flat runway of two or three kilometers. The aircraft carrier pulls the wing root with a steel cable on the deck of more than 100 meters, or grabs the front wheel with a traction rod and violently throws it out (catapults off), or "bumps" into the springboard and flies out (jumps) after starting the force, especially the former has a great impact on the life of the aircraft.
The approach of land-based aircraft has a long period of low altitude and small angle descent, and there is also a "flat floating" flight on the runway of two or three kilometers long. Finally, the smaller the landing angle, the better, and the farther the landing impact of "shooting down" is. The stress on the fuselage and landing gear is small. However, the landing runway on the deck of the aircraft carrier is often less than 200 meters and is still swinging up and down. Obviously, the landing angle of the aircraft carrier must be large, and there will be no "flat drift". People who often watch military videos will find that the boarding method of the aircraft carrier is "flapping", with a large angle of descent, slapping the deck of the aircraft carrier rudely, and then stopping Suoshengla from dragging hard by landing. F/A 18 Bumblebee landed at a descending speed of 6 m/s, which is a real "shoot" on board. The aircraft carrier and landing gear must be strengthened, and every take-off and landing is an obvious damage to the life of the structure. Aircraft carrier take-off and landing training is far more harmful to the life of aircraft carriers than land-based aircraft take-off and landing training.
It can be seen that only specialized trainers made of leather are suitable for use as trainers on board. Once the L- 15 is mass-produced, the training cost per hour will be one order of magnitude lower than that of the drone. It is estimated that the training cost is as low as 3-4 thousand USD/hour (land-based type). Equipped with a suitable trainer, a large number of valuable fighters will be liberated for combat readiness duty and new tactics research, which will bring extremely obvious economic and combat readiness benefits.
L- 15 also has excellent fly-by-wire control characteristics and partial subsonic and transonic flight performance of the third generation fighter, which can better simulate the flight characteristics of the new generation fighter. Its stable hovering ability reaches 6G, while the maximum value of the third generation fighter is only 9G, which can fully meet the general flight simulation requirements.
Its aerodynamic shape determines its low-altitude and low-speed flight performance and stability, which is very suitable for the low-speed flight requirements of carrier-based aircraft taking off and landing. Its double-engine characteristics can simulate a single-engine parking accident. Once a real single-engine accident occurs at sea, it can better return to the aircraft carrier for skydiving or land at the alternate airport.
L- 15 has a design thrust-to-weight ratio exceeding 1 and good lift performance, which also enables it to carry enough training fuel and payload when meeting the takeoff and ejection requirements of medium and large aircraft carriers. Its minimum takeoff speed is 240 km/h, the minimum takeoff distance is 300 meters, and the minimum landing distance is about 400 meters. L- 15 has good short-range take-off and landing capability, and there is room for the modified ship to take off and land, so no major changes are needed.
Also as a light aircraft, L- 15 is superior to the carrier-based two-seat fighter in convenience and carrying capacity. Especially at the beginning of the design, the L- 15 adopts double engines, which means that the structural weight is increased by 10%- 15% compared with that of a single engine, and the shape resistance is great. If the RD33 turbofan engine of FC 1 fighter is adopted, it means that the fuselage length will be lengthened (MIG-29 is 17.32m, FC 1 yes 14.30m, and L 15 is only 12.27m). Now L- 15 shortens the engine compartment and even the overall length, just to get on the carrier-as a carrier aircraft, its short stature can save space on the cramped flight deck.
L- 15 adopted full authority digital control system (FADEC) on the engine at the beginning of its first design in China. Most of the previous aircraft had some restrictions on the operation of engine throttle, such as different altitudes and speeds, and some special situations, such as engine restrictions at high angles of attack. In the complicated and tense landing flight, the general pilots often forget some limitations of the engine, and misoperation is likely to bring serious consequences such as parking in the air. The appearance of FADEC lightens the mental burden of pilots, reduces the fatigue of pilots and reduces mistakes. FADEC system uses computer to monitor and adjust the engine to keep the engine in the best working condition and provide safety diagnosis and inspection. FADEC technology has been widely used in civil aircraft, and all new fighters in the future will adopt FADEC control technology.
The L- 15 engine compartment is designed with a "big open cover", which can be easily opened for maintenance, especially for debugging and maintenance on a small and cramped aircraft carrier. Good maintenance function enables L- 15 to achieve high attendance.
L- 15 has a prominent feature: the longest blank time is 4 hours. A long blank time means that you can take off with less oil and have a good blank time, which also means that you can train more subjects, reduce the number of landings and improve economy. Aircraft carriers often deliberately reduce the fuel load and save the take-off weight to facilitate take-off, and often encounter the situation of "queuing in the air" waiting for landing. At this time, L 15 can hover calmly, leaving the deck runway for other aircraft that need emergency landing. The longer blank time makes L- 15 more flexible when used on aircraft carriers.
L- 15 front landing gear is retracted into the nose, and the main landing gear with knees and legs is retracted into the fuselage. This design leaves room for the reinforcement and transformation of the front and rear landing gears, and also liberates the space under the wing. It is very convenient to use wire rope to pull and eject or front wheel to pull and eject in the future. After strengthening the structure, it can adapt to the rough requirements of aircraft carrier takeoff and landing.
In addition, some netizens asked FC 1 to be changed into a two-seater ship. FC 1 fighter has good low-altitude performance, and its three-axis and four-redundancy fly-by-wire control makes it have good low-altitude performance. Due to the planned mass production, its cost can also be diluted. Originally, the thrust-to-weight ratio was small, and the internal space of the aircraft was relatively small. As a single-seat fighter, it can meet the needs. After refitting two seats, increasing the resistance, increasing the weight brought by the landing equipment and strengthening the structural strength will become more prominent and need more changes. Changing it has no value and technical feasibility.
The biggest problem that bothers L- 15 is the engine. As an aircraft carrier-based trainer, the demand of L- 15 is much less than that of Air Force and HNA land-based trainer, so the problem that the engine can not be localized is not so serious: the number of equipment is limited, and it can be dealt with as long as some spare engines are properly hoarded. Just because the production is small, its cost will be abnormally high, but it is still affordable. With the acceleration of domestic turbofan 1 1 of AI-222-25F in the future, it is probably not too late to catch up with the ship.
With the boarding of L- 15, China will welcome the first shipborne fixed-wing trainer. It can simulate the take-off and landing of the third generation fighter, as well as long-range attack, ship-to-ground attack and air combat. It is a real multi-purpose carrier-based trainer.