Comet de Havilland
Comet 4C (9V-BAS) in Malaysia-Singapore Airlines colors; Hong Kong Airport - Kai Tak, May 1966
The world's first jet-powered passenger airliner was the British de Havilland DH-106 Comet. The plane took off on July 27, 1949, and two years later it made its first commercial flight. It was the most technically advanced aircraft and the pride of the British aviation industry. Unfortunately, as a result of a series of accidents, the airworthiness certificate was revoked and the de Havilland DH-106 Comet was stopped indefinitely. Only after the re-equipment the aircraft returned to service, becoming a safe aircraft.
The XNUMXs were the peak of the development of aircraft piston engines. However, the limited possibilities of their development gave rise to the need to create a new type of power plant, which would allow communication aircraft to reach higher speeds and flight altitudes. The development of gas turbine jet engines became the basis for the development of a passenger aircraft in which they could be used.
Lord Brabazon Commission
In 1942, at the initiative of the British government, a special air commission was set up under the chairmanship of Lord Brabazon of Tara, commonly known as the Brabazon Committee. His task was to develop the prerequisites for the development of aviation communications after the war, including the identification of promising types of aircraft. Specifications for certain types of equipment were formulated in 1943. The requirements, designated as Type I, concerned the construction of a large aircraft for 100 passengers, with a flight range of 8 thousand people. km. Based on these assumptions, the Bristol 1949 Brabazon was created in 167, but its development stopped at the stage of building a prototype. The subject of Type II requirements was the design of medium-range aircraft, of which Type IIA is a piston engine and Type IIB is a turboprop engine. It should be mentioned that the twin-engine AS.57 Airsped Ambassadors, built in 1947-1953, were created according to the Type IIA specification. (23 copies), and Type IIB - Vickers Viscount, produced in 1949-1963. (444 copies).
Like the Type III, a large medium-range propeller-driven aircraft was to be built to serve routes in the British Empire. The development of jet engines led to the phasing out of the Type III program in favor of the Type IV program with this type of propulsion. He was supported by commission member Geoffrey de Havilland, whose company was involved in the development of the first British turbojet engines and jet fighters (Gloster Meteor and de Havilland DH-100 Vampire).
The first flight of the DH-106 Comet communications aircraft took place on July 27, 1949. The purity of the aerodynamic lines of the aircraft and its “brilliant” polished surface are noticeable.
Simulation of comet DH-106
The committee's recommendations quickly became the subject of design and manufacturing scrutiny at many UK sites. The Type IV concept was developed by the de Havilland consortium, which had operating aircraft and aero engine factories and design offices. These plants analyzed the Type IV requirements and undertook a multi-stage refinement process with ever-changing technical and operational criteria.
To implement the project, various solutions were sought, ranging from a double-barreled version of an enlarged fighter, through the layout of a "duck" and a slender tailless with beveled wings, and ending with a classic communications aircraft. Thus, the first concept design of mid-1943 was an enlarged version of the DH-100 Vampire. It was supposed to be a high-speed mail aircraft with a pressurized cabin adapted to carry six passengers plus 450 kg of mail and a range of 1120 km. It had an aerodynamic design similar to the DH-100 (two-beam fuselage with a central gondola), and the power plant was three de Havilland Goblin jet engines. They were built into the rear fuselage, nacelles and air intakes in the wing bases.
A year later, the project of a passenger-mail aircraft in the "duck" aerodynamic system with engines in the rear fuselage (at the instigation of the BOAC line, work was underway on a purely passenger version). However, in 1945, work was underway to design an aircraft with a capacity of 24-36 seats, in the "flying wing" aerodynamic system. Passengers were placed in the center of the wing, and the power plant consisted of four Ghost engines. They were de Havilland's designs and had already been used in British jet fighters (such as the Vampire).
The adopted design of the aircraft was a bold technical project, the completion of which required the construction of an experimental de Havilland DH-108 Swallow jet. During intensive testing, the aerodynamic system was gradually improved, as a result of which the airframe took the form of a classic low wing with four engines at the base of the wings. Design work was completed at the turn of August and September 1946, and the aircraft received the designation de Havilland DH-106.
Construction and testing of prototypes
On September 4, 1946, the British Ministry of Supply signed a contract for the construction of two prototypes, designated G-5-1 and G-5-2 (order No. 22/46). Earlier, at the end of 1944, BOAC (British Overseas Airways Corporation) determined its requirements for 25 aircraft, but decided to order eight aircraft, and after the adoption of the British South American Airways line, this was increased to 10.
Design work on the prototypes at the de Havilland factory in Hatfield (north of London) was initially done in secret. The designers faced many challenges, such as: the strength of the hermetic cabin structure; flying at high altitudes and at high speeds; fatigue of materials and resistance to aerodynamic heating (the famous Polish aircraft designer Stanislav Praus participated in the design work). Since the new aircraft was far ahead of its time in terms of technical solutions, several research programs were launched to obtain the necessary scientific base.
The new engines were tested after they were installed on the Avro 683 Lancastrian bomber (the Avro 683 power plant consisted of two jet and two piston engines) and on a de Havilland DH-100 Vampire, TG278 specially prepared for high-altitude flights. The hydraulic control system was tested on the Lancaster PP755 aircraft, and its individual elements were tested on the DH-108 Swallow and DH-103 Hornet. An Airspeed Horsa landing glider was used to test the view from the cockpit, on which the streamlined leading edge of the wing of the DH-106 aircraft was built. The pressurized, high-flow refueling system (one ton of fuel per minute) was developed by Flight Refueling Ltd. To streamline staff training and commissioning, de Havilland designed the cockpit and passenger deck layout similar to that already used on the popular Lockheed Constellation aircraft. The cockpit equipment included dual control systems for the captain and first officer, while the flight engineer controlled the main installations, including hydraulic, fuel and air conditioning.
The first prototype (unpainted) was rolled out of the assembly shop in Hatfield on July 25, 1949. Two days later, on July 27, it flew, which also became the first flight of a passenger aircraft with such a power plant to Mir. It lasted 31 minutes, and the crew commander was an officer of the Royal Air Force, the head of the test pilots of the company Capt. John Cunningham. The co-pilot was Harold Waters, and the crew included three test engineers: John Wilson (avionics), Frank Reynolds (hydraulics) and Tony Fairbrother. This flight marked the beginning of a multi-month qualification testing program. Tests of the new aircraft were carried out with great intensity, and in the first two weeks there were 14 of them, reaching a 15-hour flying time.
The aircraft turned out to be controllable throughout the entire speed range, the climb was 11 m, and the landing speed was 000 km/h. In September 160, the prototype was registered as G-ALVG and then took part in the Farnborough Air Show. During the tests, modernization work was carried out to improve the design of the airframe. Among other things, the original chassis layout with one large carrier wheel was not suitable for production vehicles (the wing root design was an obstacle). From here, from December 1949, tests were carried out on a two-wheeled chassis, and then for several months a four-wheeled bogie with small wheels. The four-wheel bogie chassis system later became standard in series production.
During test flights, he set many record results that were previously unattainable by other communications and military aircraft. For example, on October 25, 1949, John Cunningham, together with a crew of three and a cargo of 36 passengers, made a return flight on the London-Tripoli route with a length of 4677 km, with an average speed of 726 km / h and an altitude of 11 m. The flight time was 000 hours 6 minutes (excluding the time of an intermediate landing in Tripoli) and was two times shorter than the Douglas DC-36 and Avro York piston aircraft operating on this route. Another flight in February 4, performed in the British Isles and the Atlantic Ocean, reached a flight duration of 1950 hours 5 minutes and a ceiling of 30 m, and on the Brighton-Edinburgh flight (12 km) the average speed was 200 km / h. Flights on the international routes planned for its service became a good advertisement for the aircraft, i.e. in March 715 from London to Rome (850 hours), and in April to Cairo (1950 hours).
In the mid-1950s, the prototype was tested in the tropics in Nairobi and Khartoum, and in September participated in a demonstration in Farnborough (he was the first operator of the BOAC line). After the exhibition, the aircraft was equipped with an in-flight refueling probe and spent several weeks conducting such qualification tests. They turned out to be negative and, therefore, they refused to improve it. In May 1951, Sprite boosters were tested at Hatfield Airport. They were installed near the exhaust pipes of the engines to provide additional thrust when taking off from high altitudes or in hot climates. Tests confirmed better takeoff performance, but due to the high volatility of the propellant and expected handling problems, it was not used.
The second prototype G-5-2 with registration plates G-ALZK took off on July 27, 1950, the crew commander was again Captain W. John Cunningham. Compared to the first sample, it had several design changes, and outwardly it differed primarily in the shape of the main chassis. Single wide wheels with a pneumatic diameter of 1675 mm were converted into a bogie with four small ones, which fit more easily into the outline of the wing and provided a more rational distribution of the weight of the aircraft along the runway. In addition, the wings were redesigned, adding characteristic additional fuel tanks in front of the leading edge, and new avionics systems were applied. This aircraft joined the first prototype and jointly completed the test flight program.
In April 1951, the second prototype was handed over to BOAC for a period of several months, where it implemented a 500-hour training program for aviation personnel at Hoern Airport, and was also used for operational testing of equipment (in the final stage of operational testing at the airfields of several production aircraft). Type certification qualification flights ended in mid-January 1952, and the corresponding Airworthiness Certificate was issued on January 22, 1952.
The further fate of the prototypes was as follows. At the end of December 1952, G-ALVG was still flying with modified wings fitted with additional fuel tanks, with the task of evaluating their suitability. From July 1953, it underwent destructive life tests, and after their completion it was decommissioned and deregistered (November 6, 1953). On the other hand, the G-ALZK prototype was dismantled after testing was completed. Its fuselage was transferred to Farnborough and then to the BAe plant in Woodford, where it was used for further development of design solutions (for example, the Nimrod maritime patrol aircraft).
The first production Comet 1, G-ALYP, and two prototypes, G-ALVG and G-ALZK, in a demonstration flight.
Serial production of Comet 1/1A
Based on a BOAC order for ten aircraft at a fixed price of £250, De Havilland made the risky decision to go into series production. The manufacturer assumed that the next orders would arise as soon as prototypes appeared and serial vehicles entered service. This also happened. As prototype testing began, Canadian Pacific Airlines (CPA) ordered two aircraft in 1949, and two years later French airlines Union Aermaritime de Transport (UAT) and Air France bought three. Military aviation also became interested in the aircraft, and the first two were ordered by the Canadian Air Force of the Royal Canadian Air Force.
The first aircraft of the Comet 1 series (reg. G-ALYP, serial number 06003) was transferred to BOAC on April 8, 1952, and the last of ten ordered on September 23, 1952 (G-ALYZ, serial number 06012). No. 1). Then the de Havilland factories began to fulfill foreign orders, and the produced aircraft were given the type designation: Comet 1952A. In October 06013, the first such aircraft was delivered to Canadian Pacific Airlines (CF-CUM, no. 1953), and in January 06014, the second (CF-CUN, no. 1). French airline UAT received three of its Comet 1952A: December 06015 (F-BGSA, c/n 1953); February 06016 (F-BGSB, w/n 1953) and April 06019 (F-BGSC, w/n 1953). In May 1, the first Comet 5301A (tactical number 06017, b/n 5302) was handed over to the Canadian military aviation, and the second one a month later (06018, b/n XNUMX).
