AN-12
Vocabulary
Turboprop, cantilever, double-slotted flap, stressed skin, dihedral tip panel, pressurized compartment, engine shutdown.
The AN-12 cargo turboprop aircraft was developed in 1957 by Antonov Design Bureau for medium- and long-haul cargo operations. The An-12 is configured as a cantilever metal monoplane with high-mounted wing, elevated fuselage tail, single-fin tail and retractable three-strut landing gear with steering nose wheel. The landing gear wheels with low-pressure tires permit to operate the aircraft from the unpaved airfields.
Four AI-20 turboprops are mounted on the wings furnished with double-slotted flaps. The aircraft fuselage is of a circular semi-monocoque type with smooth stressed skin. The aircraft half-wings are mounted with negative angle of dihedral tip panels for better lateral dynamic stability, decreasing influence of emergency engine shutdowns and wind gusts on the aircraft lateral- directional dynamics. The pressurized compartments for crew and personnel accompanying equipment in flight are located in front of the cargo cabin. The fuselage tail accommodates the pressurized back-seat compartment for observation gunner. The non-pressurized cargo cabin is equipped with ventilation and heating system, tie-down points, cargo ramps, handling winch and 2300 kg capacity monorail hoist. The An-12 aircraft fuselage with elevated tail and big cargo door provides for convenient conditions of large-size cargo handling and parachute dropping. The 2.5t capacity airborne cargo handling device and quick-release transporter facilitate and accelerate loading, mooring and unloading operations. The loading of large-size equipment is made through cargo door with ramp in the rear part of fuselage. The cargo cabin is not pressurized and equipped with individual oxygen supply system.
The flight-control and navigation equipment includes a compass system, autopilot, short-range radionavigation system equipment, electronic system of instrument landing, automatic radio direction finder (RDF), radio altimeter, navigation system. The radio communication is provided by HF and VHP radio sets, aircraft interphone system, emergency radio set.
2760
I. Read the text and answer the questions.
1. What kind of aircraft is the AN-12?
2. What are the main structural features of this aircraft?
3. What provides operation of the AN-12 from unpaved airfields?
4. What compartments are pressurized and why?
5. What provides large-size cargo handling and parachute dropping?
II. Make up a summary of the text.
UNIT 2
AN-24
Vocabulary
Auxiliary power plant, nacelle, double-slotted flap, wing root, ventral fin, hydraulically-retractable three-strut landing gear, ram, cockpit, rivet joint, adhesive-bonded joint, integral fuel tank, engine air intakes cowling,
The aircraft was developed in mid-sixties. It is powered by AI-24 jet-prop engines. The performed tests and aircraft operation revealed that it is featured with a good stability and easy controllability, capable to continue one engine inoperative takeoff. AN -24 is equipped with RU-19A300 auxiliary power plant of 800 kgf-thrust mounted in the RH turboprop nacelle. This engine improves the aircraft take-off performance.
|
|
|
An-24 is configured as a cantilever monoplane with high-mounted wing equipped with extended Fouler flaps. The double-slotted flaps are externally fitted at the engine nacelle and single-slotted flaps are installed at the wing root. The tail unit has a traditional design; aircraft is completed with a ventral fin. The aircraft is provided with reliable wing and tail unit anti-icing systems. The fuselage is of a semi-monocoque type.
The hydraulically-retractable three-strut landing gear has double wheels at each strut, steerable nose wheels, providing pressure inside tires to be adjusted on the ground. The landing gear construction and mechanical design ensure its extension by gravity or by ram air even if any system fails. The main landing gear struts are installed in the engine nacelles and are retracted against ram air into special compartments. The nose wheel is installed at the fuselage front end and is retracted into compartment under the cockpit. The nose strut is a pedal-controlled unit that significantly improves the aircraft mobility on the ground. The landing gear wheels with low-pressure tires allow landing at wet unpaved aerodromes.
The adhesive bonded joints were for the first time applied for An-24 in the practice of world aircraft construction. More than 67% of rivet joints were replaced with adhesive-bonded joints that resulted in the increased structure fatigue, considerable labor performance saving and production cost reduction.
The aircraft wing consists of centre-section, two middle sections and two tip sections. The wing middle sections are fitted with double-slotted flaps, while the centre-section is fitted with single-slotted flaps. Each root aileron is fitted with a trimmer and balance tab. The centre-section section incorporates four soft fuel tanks; the middle section chambers are made as pressurized integral fuel tanks.
The aircraft is equipped with communication aids and all facilities required for day and night flights in adverse meteorological conditions any season of the year. The aircraft altitude equipment produces and maintains pressure and air temperature to the extent required for the crew and passengers normal vital activity when flying at high altitudes.
In icing conditions the wing leading edge, tail unit and engine air intakes cowlings are heated with hot air taken from the engine compressors. The propellers, cockpit windshields, pitots, batteries containers are provided with electrical heating.
If required, An-24 can be easily converted either to a cargo-passenger or cargo version. An-24 aircraft is one of the best world examples of aircrafts for its reliability and operating life.
2620
I. Read the text and answer the questions.
1. What kind of engines is An-24 equipped with?
2. What is the configuration of the landing gear?
3. Where are the single- and double-slotted flaps located?
4. What kind of fuel tanks are used in this airplane?
5. What provides comfortable conditions for crew and passengers?
NOTES:
Pitot = Pitot gage = ,
