Il-18 Coot

The Ilyushin Il-18 (NATO reporting name: Coot) is a four-engined turboprop airliner designed by the Ilyushin design bureau in the Soviet Union. It first flew on 4 July 1957 and became one of the principal Soviet medium-haul airliners, later serving as the basis for military reconnaissance, electronic warfare and command post derivatives still flown by the Russian Aerospace Forces. Many airframes exceeded 45,000 flight hours.

Development

A Soviet Council of Ministers directive of 30 December 1955 tasked Kuznetsov and Ivchenko with new turboprop engines and Ilyushin and Antonov with airframes to use them, producing the Il-18 and the Antonov An-10. Ilyushin work had begun in 1954, drawing on the abandoned 1946 piston-engined aircraft of the same designation. The prototype SSSR-L5811 was rolled out in June 1957, began taxi trials on 1 July and first flew from Khodynka on 4 July 1957, being presented at Moscow-Vnukovo on 10 July alongside the An-10 and Tu-114 prototypes under the name Moskva, which was dropped for production. Moscow Machinery Plant No. 30 at Khodynka built the type, reducing Il-14 output during 1957. Around 20 Il-18As were completed before the Il-18B, with higher gross weight and a longer nose radome, flew on 30 September 1958. Persistent Kuznetsov NK-4 problems led to a July 1958 decree switching all production from November 1958 to the Ivchenko AI-20, with earlier aircraft re-engined. The Il-18V appeared in December 1959 and remained in production until 1965, with 334 built. Seventeen foreign carriers took some 125 aircraft.

Design

The Il-18 is a low-wing monoplane with a circular pressurised fuselage of 3.5 m diameter and conventional tail. The forward-retracting tricycle landing gear uses four-wheel main bogies that rotate 90 degrees to retract into the rear of the inboard nacelles. Two port-side entry doors are fitted fore and aft of the wing, with two overwing emergency exits per side. It carried nose weather radar and was the first Soviet airliner with an automatic approach system. From April 1961 a TG-18 auxiliary power unit replaced lead-acid battery ground starting, and some aircraft could run the APU in flight. The Il-18D is powered by four Ivchenko AI-20M turboprops of 3,170 kW driving 4.5 m four-bladed AW-68I propellers, with 30,000 L of fuel, a 64,000 kg maximum take-off weight, 625 km/h cruise at 8,000 m and 6,500 km range with a 6,500 kg payload. Avionics include RPSN-2AMG or RPSN-2N Emblema radar, NAS-1B navigation system, DISS-1 Doppler sensor, RSBN-2S Svod, SP-50 Materik ILS and SR-2M Khrom IFF.

Operational History

Between 1958 and 1960 the type set 25 world records for range and altitude with various payloads, with Vladimir Kokkinaki as test pilot, and won the Brussels World Fair Grand Prix in 1958. Il-18s remained in service in Siberia, North Korea, the Middle East, Africa and south Asia, with seven aircraft in airliner service with six operators as of July 2018. The Il-22PP electronic warfare aircraft entered service in October 2016 and a modernised Il-20M in July 2020, supporting Kh-47M2 Kinzhal targeting. An Il-20M was accidentally shot down near Latakia, Syria on 17 September 2018 with 15 aboard; an Il-22 command post was shot down on 24 June 2023 during the Wagner Group rebellion, killing ten crew; another Il-22 was reported damaged beyond repair after a crash landing at Anapa on 14 January 2024.

Variants

• Il-18B: First major production model, a medium-haul airliner seating 84 passengers.
• Il-18V: Standard Aeroflot version in service from 1961 with four AI-20K engines and 90–100 seats.
• Il-18D: Long-range model with an extra centre-section fuel tank and four AI-20M engines.
• Il-20M (Coot-A): COMINT/ELINT reconnaissance conversion.
• Il-22 (Coot-B): Airborne command post, with the Il-22M and Il-22PP electronic warfare derivatives.