Harbin Y-11 CHAN - Variants
The Y-11 aircraft has a geological exploration type, Y-11B and Y-11T and other derivative models. The Y-11 is now used primarily in agricultural, forestry and geophysical survey applications. Other possible applications include short-haul and aeromedical transportation, fishery protection, firefighting and flying training. Features include two radial engines, capability for rough field operations and STOL performance. Y-11s have seen service as commuter airliners and have also been configured and used for ag spraying.
The Y-11B is an improved development powered by Teledyne Continental engines to overcome single engine altitude performance shortfalls. The first Y-11B's maiden flight was on December 25 1990.
Geological prospecting machine
The Yun-11 geological exploration aircraft is a special-purpose aircraft improved by the Harbin Aircraft Factory on the basis of the Yun-11. The Ministry of Geology and Mineral Resources of China (then called: Ministry of Geology) wanted to use the aircraft in large numbers to carry out exploration tasks since the beginning of the Yun-11 project, and gave a lot of support in the development of the Yun-11 at Factory 122. At that time, the Ministry of Geology hoped to install the DKM-1 pulsed airborne electromagnetic instrument and the CHHK-1 and CHHK-2 airborne proton precession magnetometers developed in the late 1970s on the Yun-11 aircraft.
On June 7, 1980, the Ministry of Geology and the Ministry of Three Machinery jointly issued the "Agreement on the Geological Type of the Yun-11 Aircraft and the Problem of the Address Prospecting Flight Team", and decided to set up a geological team by the Agricultural Aviation Service Team of the 122nd Factory. The department is responsible, and the personnel are responsible for the factory. In July 1980, the Yun-11 geological exploration aircraft flew in the Xuzhou area to conduct a pilot-production flight for aerial electromagnetic measurement, and the two sides cooperated well.
Yun-11B
The Y-11B is an improved version of the Y-11 with an engine change. After the Yun-11 aircraft was put into operation, it was found that the reliability of the aircraft and the engine was not high, the interval between overhauls was short, and the power of the two piston-6 D-type engines was still insufficient, the commercial horsepower was relatively small, and the operation economy was poor. , The aircraft cannot meet the airworthiness requirements due to its lack of single-engine flight capability and poor safety. In addition, the agricultural equipment supporting the aircraft is backward in technology, the system accessories are not matched, and there are many failures. The seed sowing equipment has no device to control the sowing amount, the sowing width is narrow, and the sowing quality is difficult to guarantee. The pesticide pump of constant spraying equipment has low pressure and atomization. The effect is poor, and the ability of the aircraft cannot be fully utilized.
In response to the above problems, Harbin Aircraft Manufacturing Company began to make further improvements to the Y-11 aircraft in accordance with the CCAC-23 Department of China's Civil Aviation Airworthiness Regulations in 1988. In December 1988, the Ministry of Aeronautics and Astronautics approved the overall modification design plan, named Yun-11B. There are two types of modification schemes. One is the Y-11BI with foreign engines and airborne equipment, and the other is the Yun-11BII with domestic engines and airborne equipment.
Harbin Aircraft Manufacturing Company first developed the Yun-11BI. The wing structure was redesigned on the basis of the Yun-11 aircraft. A structurally sealed integral fuel tank was set in the middle of the wing. The vertical stabilizer was made of sets of reaming bolts and the fuselage. The tail section is connected to facilitate disassembly, packing and transportation, and the horizontal stabilizer with a larger area is used to increase the flight stability. The power plant is changed to a TSIO-550-B piston engine with a turbocharger developed by Continental Corporation, with a single power of 350 horsepower. The propeller matched with the engine was also changed to a three-bladed propeller with a governor and a return accumulator from Hazel. Due to the increased diameter of the propeller, the installation position of the engine on the wing was moved outward a little.
The increase in engine power enables the improved Y-11BI to achieve a maximum level flight speed of 265 km/h, a cruising speed of 200 km/h, and a maximum range of 1,080 km. Airborne equipment includes all navigation instruments, engine instruments and electronic equipment required by the visual and instrument flight rules for general aviation flight, including short-wave radio and VHF radio (two) in the communication system and audio control panel, navigation The beacon, radio compass and gyro magnetic compass of the system are all products of American King's Company. The empty weight is increased to 2350 kg, the normal take-off weight is 3500 kg, and the commercial load is 900 kg.
In October 1989, Harbin Aircraft Manufacturing Company started the modification design of the Yun-11BI aircraft, and completed a full set of modification design drawings by June 1990, and started process equipment manufacturing and parts production in August. A total of two prototypes were built, one for the full-machine static failure test and the other for the performance qualification test flight. On December 5, the final assembly and ground test of the first prototype was completed. On December 26, the No. 01 prototype made its maiden flight successfully. In 1992, the Yun-11BI aircraft obtained the type certificate issued by the Civil Aviation of China. However, due to the lack of market demand analysis and demonstration at the beginning, and the high price of imported engines and electronic equipment, the Y-11BI aircraft was not cost-effective. The original plan to use the piston-6K engine and domestic airborne equipment Yun-11BII type program has not been developed.
Yun-11T
The Yun-11T aircraft is an improved transport aircraft with turboprop engines. In the late 1970s, the Yun-11 geological exploration aircraft was initially tested by the Aerogeophysical Exploration Corps of the Ministry of Geology and Minerals. The Aerogeophysical Exploration Corps believed that the commercial load of the aircraft was too small to meet the requirements for use. It is a special small aircraft for geological exploration with a take-off weight of about 5,000 kilograms, similar to the DHC-6 "Twin Otter" introduced from Canada not long ago. However , there was a lot of disagreement in the technical demonstration of the plan as to whether the new aircraft was powered by a piston engine or a turboprop engine . Although the fuel consumption rate of the piston engine is lower than that of the turboprop engine, it is more economical to use, and it is less difficult to develop in China. The turboprop engine has the advantages of light weight, small windward area, long maintenance life, relatively low vibration and noise, but the cost is high and cannot be developed in China. Harbin Aircraft Factory decided to develop a turboprop aircraft after weighing and considering that the turboprop engine is more in line with the future technological development trend.
However, because the development of the new turboprop aircraft was not included in the new aircraft development plan of the Ministry of Aviation Industry at that time, the research and development funds allocated by the Ministry of Aviation Industry were not available. In order to obtain the available aircraft as soon as possible, the Ministry of Geology and Minerals decided to allocate 1 million yuan for the research and development of the new aircraft. The two main products of the Harbin Aircraft Factory at that time, the H-5 bomber and the Z-5 helicopter , were discontinued one after another due to their backward performance, and the development of the Shuihong-5 seaplane was also stagnant. the predicament. Seeing that the small turboprop aircraft has good market prospects, the Harbin Aircraft Factory decided to try to raise funds by itself and the Ministry of Geology and Minerals to develop new aircraft in the name of the Yun-11 aircraft improvement and development project without the funds allocated by the Ministry of Aviation Industry. It is a small turboprop transport aircraft, and it is called the Yun-11T.
The Y-11T still uses the general layout of the Y-11 aircraft with two engines, a single wing on a diagonal strut, and a single vertical tail, but on the basis of which the size of the body has been enlarged. The height of the machine is 5.57 meters. The wing adopts a high lift-drag ratio airfoil newly developed at that time with a relative thickness of 17%. This airfoil has large lift, low drag, good stall characteristics, and good handling quality under various flight conditions, so it is effective. improve the flight performance of the aircraft. The wing area and tail area are also increased accordingly. The relatively thicker wing also significantly increases the volume of the internal overall fuel tank, and the maximum fuel load increases to 1230 kg, thereby increasing the maximum range of the aircraft to 1280 km. The vertical and horizontal tails are all metal structures. The rudder and elevator are also changed from the cloth skin of the Y-11 aircraft to the metal skin. Each rudder surface is equipped with an adjustment piece, which is controlled by an electric mechanism installed on the front edge of the rudder. The plane has better maneuverability.
The fuselage of the all-metal semi-monocoque structure is composed of the cockpit, the cargo compartment, the front and rear luggage compartments and the tail section. The cross-sectional shape of the fuselage is a rounded rectangle, and the interior is relatively spacious. The shape of the nose is more streamlined than that of the Yun-11 aircraft. The cockpit is equipped with two large aviation plexiglass windshields and left and right side windows. The windshields are equipped with electric windshield wipers. The seat, the driver's observation field is relatively wide. The middle section of the fuselage is a non-airtight passenger and cargo compartment, with a length of 4.82 meters, a maximum width of 1.6 meters, a maximum height of 1.7 meters, and a volume of 12.9 cubic meters. The two side walls of the cargo hold are slightly bulged outward in a drum shape, which greatly improves the rigidity of the rectangular flat skin originally used by the Y-11 aircraft, and can effectively prevent the skin from being agitated and fatigued. There are four square aviation plexiglass portholes with a size of 0.45m x 0.6m on each side of the cargo hold. The large transparent portholes make the light in the cargo hold bright and reduce the feeling of depression. The right side of the cargo compartment features two dimensions of 0.68 x 0. 68 meters of emergency exit, there is also an emergency exit of the same size on the left side. The cabin door at the rear of the cargo compartment is composed of two parts, the front and the rear.
When boarding the plane, only the small cabin door in the latter half is used, which is opened outward, and a simple escalator is provided for passengers to use when getting on and off the plane. When loading cargo, the front half of the hatch can be opened inward, and the expanded hatch size can facilitate the loading and unloading of large cargo. In order to reduce the weight of the fuselage structure as much as possible, the connection between the skin and the long section of the fuselage and wings is widely used to replace the traditional riveting process, the nose cover, front luggage compartment, tail cover and wing support The non-stressed components such as the fairing of the rod are also made of light-weight and high-strength FRP materials. Since the required small turboprop engines could not be provided in China at that time, two PT6A-10 turboprop engines from Pratt & Whitney of Canada were selected to replace the piston engines on the original Yun-11 aircraft. Increased to 475 shaft horsepower, the aircraft has a single launch capability.
The refurbishment life of the PT6A-10 engine reaches 3,500 hours, which is much higher than that of the piston-6 A-type engine, thus ensuring that the aircraft has a high utilization rate. The supporting propeller is a three-blade metal propeller with variable pitch, feathering and reverse propeller produced by American Hazel Company. The reverse propeller function can significantly shorten the landing roll distance of the aircraft, and the weight and flight speed are higher than - 11 Under the condition that the aircraft has been greatly improved, the landing roll distance has not increased much, only 280 meters. The riding environment in the cabin is also significantly improved compared with that of the Yun-11 aircraft. A ventilation and heating system is installed on the aircraft, which can draw hot air from the engine to warm the windshield and the driver's feet in the cockpit.
The cockpit and cargo compartment are naturally ventilated. Heating and forced ventilation are optional. Various flight and engine indicating instruments are installed in the cockpit, as well as CT-1 VHF radio station, JDT-2 high frequency radio station, JT-5A intercom, WL-7 radio compass, WG-4 radio altimeter , XS-6 beacon receiver and other relatively complete communication and navigation equipment, and optional weather radar and autopilot according to mission needs. Ensure that the aircraft can fly safely under VFR or IFR and non-icing weather conditions.
After the design plan demonstration, wind tunnel blowing test and multiple rounds of performance and strength calculations, the overall designer of the Y-11T aircraft was determined at the end of 1979, and the design drawings of the entire aircraft were completed in October 1980. During the design process, it was found that the power of the originally selected engine was too small. In order to ensure the flight performance and single-launch landing capability of the aircraft, it was decided to use the PT6A-I 1 turboprop engine with a power of 500 shaft horsepower from Pratt & Whitney. In 1981, Harbin Aircraft Manufacturing Company completed the design and manufacture of the process equipment required for trial production, and the first batch of three prototypes was put into trial production. During the trial production process, key process technologies such as integral rib and wall plate, integral fuel tank, skin long-separation bonding process, glass fiber reinforced plastic and honeycomb structure manufacturing were successively conquered. In March 1982, the No. 01 prototype for static test was completed. The final assembly passed the static test of the whole machine and the ground simulation test of other systems at the end of June of the same year.
By July, the final assembly of the No. 02 prototype for test flight was completed. On July 14, 1982, the No. 02 prototype flew successfully for the first time. The successful trial production of the Yun-11T aircraft also changed the view of the Ministry of Aviation Industry. On January 31, 1983, the Ministry of Aviation Industry officially approved the project development of the Yun-11T aircraft, and allocated funds to support its subsequent identification, test flight and improvement. Since the Yun-11T aircraft is superior to the Yun-11 aircraft in terms of structural layout and overall performance, the Ministry of Aviation Industry has given it a new model number, named as the transport 12 aircraft, referred to as the Yun-12 aircraft, and officially listed in the development plan of the Ministry of Aviation Industry.
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