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Antonov An-10 Cat - Design

The design priority remained the parameters of the AN-12 and it was their passenger version that was inherited for themselves. There were pluses in it, there were minuses, and the pluses, perhaps, can be attributed only to the economic side of the issue, and to the low quality of the airfield network of that time. And the negative was that the plane was overweight and, as a consequence, had reduced range and commercial weighting opportunities. In addition, a significant problem was to ensure the air-tightness of such a large fuselage, which inevitably has doors and hatches for various purposes.

The first thing that catches the eye is a very wide (by the standards of that time for passenger aircraft) fuselage. It is clear that such dimensions were due to the possibility of loading large-sized cargoes and equipment into the cargo compartment of the transport. Because of this, passengers received a large, well-designed and equipped interior, which, depending on the load (variant of location and number of seats) could even be very spacious. Impressive is the height of the ceiling, which, perhaps, you will not see even on modern wide-bodied airbuses. The AN-10 is a freestanding monoplane with a high-wing wing, on which four IGHI Ivchenko AI-20 turbines are installed with a takeoff power of 4000 e. each with screws AB-68 with a diameter of 4.5 m (on the first test aircraft were installed TVD NK-4 designs ND Kuznetsov capacity 4000 e.ls).

The fuselage is an all-metal beam-stringer semi-monocoque with a diameter in the maximum section of 4.1 m. The transverse set of the fuselage consists of 68 frames and 9 half-spoons, and a longitudinal set of 110 stringers.

The fuselage is divided into four compartments. In the bow of the first compartment there is a crew cabin, which includes a commander, a second pilot, navigator, airborne operator and air mechanic. Then the front passenger cabin is placed for 25 seats, then - the compartment of the household premises (wardrobe, kitchenette and trunk). Behind the utility compartment there are an average passenger compartment for 46 seats and a rear passenger compartment for 13 passengers. In the cockpit and in passenger compartments, a pressure drop of 0.5 kgf / cm2 is maintained, which makes it possible to provide comfortable conditions at a flight altitude of 10,000 m. Cargo and luggage compartments are located under the floor of the passenger rooms. Loading and unloading are carried out through the hatches on the starboard side.

Passenger armchairs (double and built) were strong and light. The frame of the seats is made of aluminum and magnesium alloys. The armchair is equipped with an ashtray, a call-button for the flight attendant, an individual lamp and a radio head, which can be switched on at will of the passenger. The average width of the passage between the blocks of seats is 410 mm. The floors in the salons are covered with carpets.

Landing and exit of passengers are made through two doors located on the left side, and loading of bulky goods - through the back cargo door on the starboard side. On both sides there are 33 round windows.

In the tail part of the fuselage, a brake high-altitude parachute is placed in a special removable container, which is released in case of emergency depressurization in case of sudden depressurization of the cabin of the aircraft at an altitude of 10,000 m. The parachute ensures a reduction of the aircraft to a safe height of 4000 m for 2 min. In the future, according to the results of tests of the prototype, the parachute container was not used.

The wing of the aircraft is free-carrying, trapezoid in shape and consists of a center wing, two middle parts and two consoles. The middle parts carry double-slit flaps with deflectors with a total area of 27 m2 and plate ailerons (8 pcs.). On the consoles are hung two-section ailerons with a total area of 7.84 m2 with trim-servo-compensators.

Plate ailerons are curves of a plate placed on the wing perpendicular to the flow. Their control is kinematically connected with the control of ailerons, with the deviation of which the ailerons are automatically raised upward. The design of the wing is a caisson with two beam-type spars, consisting of upper and lower belts of T-section and walls. In the middle parts of the wing there are 18 soft, protected fuel tanks, in the center wing there are 4 soft-protected fuel tanks. The total capacity of all fuel tanks is 13 580 liters.

The tail plumage is free-bearing, all-metal, single-keel, without transverse V.

The engine in the gondola is attached under the wing by means of a frame with shock absorbers and a power farm. The aircraft is equipped with a neutral gas system and a fire-fighting system.

The three-axle landing gear consists of a front steerable support with two interlocked non-braked wheels measuring 900x300 mm, two main supports with four-wheeled carriages and a tail support. The base of the chassis is 9.58 m, the track is -4.92 m. The wheels of the main bearings are 1050x300 mm in size with pneumatics of a half-ball type with disc brakes. The chassis is retracted into the fuselage: the front support is back on the flight, the main supports are along the wing span towards the plane of symmetry of the aircraft. The tail support is retracted back into a special niche.

Control of ailerons, elevator and direction rudders is double, rigid, with the connection of the steering machines of the autopilot. Electrical equipment provides engine start-up, power supply of devices and radio communication, operation of fuel and oil systems, anti-icing and heating devices.

As engines for the project "U" initially planned two close on output parameters such as engine ND Kuznetsov NK-4 and engine AGIvchenko AI-20 . Both engines were new, just designed. But at the same time NK-4 was a center of innovation and advanced achievements in the field of engine building. And the AI-20 designers focused on reliability and ease of maintenance. After long hesitation and discussions, it was decided to use the NK-4 engines for the An-10 aircraft, and the AI-20 to be installed on the An-12.

However, the operation of the Kuznetsovsky engine due to the use of many new, untested solutions in it, was complicated. It was often necessary to solve the problems that arose and carry out many modifications, which hampered the planned accelerated rate of factory testing. As a result, the issue was finally resolved in favor of AI Ivchenko AI-20 engine. Later on, as the aircraft was perfected, the engines of the following series of AI-20A and AI-20K were installed on the aircraft.

The An-10 was the noisiest plane in Aeroflot at the time. AI-20 engines alone were not very noisy. The main share of noise and vibrations, which, unfortunately, was felt by the passengers (especially in the front of the cabin) were screws. The noise level in the cabin reached 122 dB. The same noise level was found only in the Tu-114, but these engines were more than four times more powerful.

The weight of the empty aircraft is 30 760 kg. At the same time, the fuselage mass is 6425 kg, the wings - 5310 kg, the tail unit - 710 kg, the chassis - 2297 kg. Flight data of the AN-10 with a take-off mass of 51 tons are as follows: cruising speed at an altitude of 8,000 m - 630 km / h; the maximum flight range with 85 passengers (and their luggage), a cargo of 800 kg and an hourly fuel balance of 3,500 km.

High-altitude equipment ensured the creation and maintenance in passenger cabins and crew cabin of the conditions necessary for flights at high altitudes. To this end, the cabin and cabin were equipped with air conditioning, heat and sound insulation and sealing hatches and doors.

The An-10 was planned for use at relatively short ranges of flights and, accordingly, with a large number of presurization cycles. Any such cycle meant the creation of an appropriate positive pressure in the passenger compartment in order to ensure normal conditions for passengers when climbing, and then reset when the altitude is lowered. That is, the elements of the fuselage structure were constantly exposed to alternating loads.

And this, in turn, means the quite likely occurrence of metal fatigue and, consequently, the loss of its strength. It is possible that this phenomenon, at the right time underestimated, contributed to the unhappy fate of the liner. After all, the more successful transport analog, the An-12, was practically rid of this. Its transport compartment was not sealed. Only the crew cabin is sealed, together with a small hermetic compartment for several people (12), adjacent to it.

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