Ilyushin Il 78

Design and development

The Il-76 tanker was conceived as long ago as 1968, but the transferable fuel load for the initial version was only ten tonnes, which was insufficient, so development was shelved. When the higher performance Il-76 became available the tanker project was restarted in 1982 as the Il-78.

In addition to the increased fuel load of the late model Il-76, the Il-78 has two removable 18,230-liter fuel tanks installed in the freight hold, giving transferable loads of 85,720 kg (188,980 lb) (with hold tanks) or 57,720 kg (127,250 lb) (without). Controlled from the gunner station, which is stripped of military equipment, three aircraft can refuel in flight simultaneously from the UPAZ-1A (Il-78) / UPAZ-1M (IL-78M) 26m refuelling pods fitted to the outer wings and rear fuselage. In addition, four aircraft can also be refuelled on the ground using conventional refuelling hoses extending from the freight hold. Because of the aircraft's high all-up weight after takeoff, which in an emergency would mean landing at weights well in excess of maximum allowable landing weight, the Il-78 has a fuel jettison system with jettison ports at the wingtips.

Soon after the Il-78 passed acceptance tests in 1984, Ilyushin was instructed to design and produce an upgraded version to be known as Il-78M. The Il-78M is a dedicated tanker and cannot be converted back to the transport role easily. Adding a third freight hold tank increased transferable fuel to 105,720 kg (233,070 lb) and maximum takeoff weight (MTOW) to 210,000 kg (460,000 lb), necessitating reinforcement of the wing torsion box. UPAZ-1M refuelling pods improved maximum fuel flow to 2,900 l/min (638 Imp gal/min). Because the Il-78M is not "convertible", all cargo handling equipment was removed and cargo doors were deleted, saving approximately 5,000 kg (11,000 lb) in structural weight.

Early versions of the Il-78 have the fuselage pod mounted on a short horizontal pylon, but the Il-78M has the fuselage pod suspended from an identical pylon to the wing pods, attached to a short stub wing. This modification was served to isolate the pod from turbulence generated by the fuselage, with the added benefit of commonality with the wing pod/pylon combination. Some Il-78s were produced with Aeroflot colours and civilian registrations, but production Il-78Ms received military markings, registration and colour scheme.

The majority of the twenty Il-78 aircraft of the Ukrainian Air Force have been permanently converted to pure transports, freight hold tanks and refuelling equipment being removed.

Operational history

All Russian Air Force Il-78s are now part of the special 203rd "Orlovski" Regiment of aerial tankers, based at Dyagilevo Air Force Base.

Variants

Il-78

The Il-78 was the original production version with two removable fuselage tanks and a maximum transferable load of 85.72 tonnes (188,540 lb).

Il-78T

Alternative designation for Il-78 due to retention of all cargo handling equipment and convertible freight hold.

Il-78M

The Il-78M entered service in 1987 as a dedicated tanker equipped with three permanent fuselage tanks, a higher gross weight of 210 tons, and no cargo door or cargo handling equipment. The cargo ramp is retained but non-functional. Total fuel capacity is 138 tonnes (303,600 lb), of which 105.7 tonnes (232,540 lb) is transferable.

Il-78M-90A (Il-478)

Based on the Il-76MD-90A. Prototype will be delivered to 2015.

Il-78ME

Export version of Il-78M.

Il-78MKI

Customized variant of the Il-78ME for the Indian Air Force. These Uzbekistan-built planes are fitted with Israeli fuel transfer systems and can refuel six-eight Sukhoi Su-30MKIs in one mission.

Il-78MP

Multi-role aerial refuelling tanker/transport aircraft, with removable fuel tanks in cargo hold and UPAZ refuelling pods, for the Pakistan Air Force, and Chinese Air Force.

Operators

As of March 2009, more than 34 Il-78s were in operation.

 Algeria

Algerian Air Force

 China

Chinese Air Force - 3 Il-78MP.

 India

Indian Air Force - 6 Il-78MKI (As of February 2014). The Indian Air Force refers to the aircraft as "MARS" (Mid Air Refuelling System) and has raised a new unit (No 78 Sqn). India is also considering procurement of six more Il-78 after scrapping deal with Airbus.

 Libya

Libyan Air Force

 Pakistan

Pakistan Air Force - four Il-78MP aircraft were ordered from Ukrainian surplus aircraft stocks, fitted with removable fuel tanks and UPAZ refuelling pods. The first of the four aircraft was delivered in December 2009. A total of four Il-78MPs have been delivered to the PAF as of May 2012.

 Russia

Russian Air Force - 19 aircraft in the 203rd Guards Air Refuelling Regiment, which is based in Dyagilevo.

 Ukraine

Ukrainian Air Force - eight aircraft.

 United States

One former Ukrainian aircraft was imported into the United States with an aim to operate the aircraft for contracted refuelling to United States military by various companies, by 2012 the aircraft was registered to the Bank of Utah.

Specifications (Il-78M)

Data from Ilyushin, UAC,

General characteristics

Crew: six

Capacity: Max 100,000 kg payload (T-6 military jet fuel)

Length: 46.59 m (152 ft 10 in)

Wingspan: 50.5 m (165 ft 8 in)

Height: 14.76 m (48 ft 5 in)

Wing area: 300 m² (3,200 sq ft)

Empty weight: 72,000 kg (158,733 lb)

Max takeoff weight: 210,000 kg (462,971 lb)

Special equipment: 3 x UPAZ-1M 'Sakhalin', (unifitsirovaniy podvesnoy agregat zaprahvki;— standardised suspended refuelling unit), refuelling pods; Two on pylons under the outer wings, and the third on the port side of the rear fuselage.

Fuel transfer rate: 900 to 2,200 liters/min

Powerplant: 4 × Aviadvigatel D-30 KP turbofan engines, 118 kN (27,000 lbf) thrust each

Performance

Maximum speed: 850 km/h (528 mph; 459 kn)

Range: 7,300 km (4,536 mi; 3,942 nmi)

Service ceiling: 12,000 m (39,000 ft)

Thrust/weight: 0.23