Tuesday, March 17, 2015

IL-102 (OES-1) close support aircraft Part II

Construction of the first prototype IL-102 and a static test airframe began in May 1980. By then the T-8 attack aircraft developed by the Sukhoi OKB had been under test for more than five years, having made its first flight as far back as January 1975.

The first prototype of the IL-102 was intended for assessing the main characteristics of the future combat machine. The second prototype was to be built at a later stage. The intention was to introduce into it design changes and improvements with a view to enhancing its performance and combat capabilities by means of fitting the aircraft with the most up-to-date avionics.

The tests showed that the firing of the cannon, thanks to their location on the fuselage under surface at some distance from the air intake lips, produced no ingestion of gun gases into the engines and, consequently, could not cause their flameout or rpm drop. Nor did missile launches affect engine operation in any way. Gunnery, missile launches and bomb release did not have any adverse effect on the work of the crew, on the instruments and the aircraft's structure.

This firing marked the completion of the IL-102's weapon tests. The test results demonstrated clearly that the IL-102 was a promising machine. This was confirmed by GK Nil VVS test pilots Colonels Oleynikov and Migunov who had been invited to take part in assessing the IL-102. They gave a high appraisal to the aircraft and committed their opinion to paper in the report on the test results. After having read the report and listened to the test pilots, the General Designer said that aircraft bearing Ilyushin's name had not received such a high appraisal even in the cases when they were introduced into service with the VVS or Aeroflot.

In the course of manufacturer's testing the IL-102 made 367 flights logging in all 248 hours and 35 minutes. The last flight took place on 29th December 1987. Not a single failure or malfunctioning of onboard systems happened; not a single incident occurred in the course of the testing. Results of the trials confirmed that the attack aircraft met on the whole the operational requirements. The take-off run and landing run proved to be slightly in excess of the stipulated figures, but, on the whole, the performance proved to be very close to the design characteristics.

Should one compare the IL-102 prototype and the production Su-25 which had stood the test of combat operations in Afghanistan, it is difficult to give an objective assessment of the qualities of the former, but some brief comparison of their performance can be made. Judging by the test results, the IL-102 was slightly inferior to the Su-25 as regards manoeuvrability and other performance characteristics; for example, the IL-102's minimum radius of banking turn did not exceed 400 m (1,310 ft). The IL-102 had a higher all-up weight comparable to that of the US Fairchild Republic A-10A Thunderbolt II attack aircraft. Being fitted with more powerful and fuel-efficient engines, it had a higher thrust/weight ratio than the Su-25. The Ilyushin attack aircraft's contours were not quite as clean aerodynamically as those of its rival; this led to extra drag, but at the same time the airframe structure was designed with a view to ensuring a maximum of simplicity and cheapness in production. The two-spar wings of high thickness-chord ratio provided enough space for the internal stowage of a part of the combat load which, in turn, reduced the aircraft's drag. The IL-102 had 16 hardpoints for the suspension of weapons and was capable of carrying a maximum warload of up to 7,200 kg (15,810 Ib), which was on a par with the characteristics of the A-10A. The IL-102's radius of action was similar to that of the Su-25. Maximum operational g-Ioad of the IL-1 02 was 5g - that is, somewhat less than the corresponding figure for the Su-25; naturally, this is an evidence of the aircraft's somewhat inferior manoeuvrability. On the IL-1 02 the electronic equipment was expected to be installed 'in accordance with the customer's wishes'; yet, in retracted position the nose gear unit was stowed so close to the short nose of the aircraft that it is difficult to say what sort of equipment could be accommodated there. It should be noted that the installation of the second seat for the aft-facing gunner and of the tail barbette increased the aircraft's weight by some 700 to 800 kg (1,540 to 1,800Ib). On the basis of tests conducted in the Sukhoi OKB it was demonstrated that the duties of a tail gunner could just as well be performed by the pilot; in this case the aircraft's weight was reduced and the firing could be made more efficient because the pilot was the first to spot the target and could himself train the tail gun, switching on a device automatically delaying the opening of fire. In turn, the IL-102 had a good view from the cockpit and was superior to the Su-25 in this respect. The Ilyushin machine was fitted with crew emergency escape means just as reliable as those of the Su-25.

The IL-102 attack aircraft, undoubtedly, was an interesting machine; yet, it was slightly inferior to the Su-25. In consequence, it was not adopted for series production and service. There was no unanimous opinion among specialists as to what kind of attack aircraft the Soviet Air Force needed - a single- seater or a two-seat aircraft. Then came the conversion of the military industry to civil production which put an end to this discussion; the IL-102 was parked in a far-off corner of the apron of the OKB's test flight facility in Zhukovskiy.

Interest in the IL-102 was revived in 1992 when the aircraft was displayed statically at the MosAeroShow-92 attracting the attention of thousands of visitors. The aircraft was painted in a green/ brown camouflage and coded 10201; various kinds of ammunition and stores that could be carried by the aircraft were displayed in front of it. Among those who took a look at the aircraft was Russia's Vice-President, Hero of the Soviet Union Aleksandr V. Rutskoy. Being a former attack aircraft pilot who had done much flying on the Su-25 and had been shot down in this aircraft as a result of a sudden attack from the rear by a Pakistani F-16, he examined the machine and its cockpit equipment very closely. Catching sight of the tail gun, he said: 'That's the kind of aircraft we need! But the calibre of the rear-firing cannon should be increased.'

Correspondence was started with a view to getting under way further development and eventual series manufacture of IL-102, but the failed coup of 1993, in which Rutskoy was one of the dissenters, and his ensuing arrest finally closed all prospects for the IL-102.

General characteristics
    Crew: 2
    Length: 175 m (58 ft 2⅞ in)
    Wingspan: 169 m (55 ft 5⅜ in)
    Height: 5.08 m (16 ft 8 in)
    Wing area: 63.5 m² (683.5 ft²)
    Empty weight: 13,000 kg (28,000 lb)
    Loaded weight: 18,000 kg (39,683 lb)
    Max. takeoff weight: 22,000 kg (48,500 lb)
    Powerplant: 2 × Klimov RD-33I turbofan, 51 kN (11,465 lbf) each
    Maximum speed: 950 km/h (513 kn, 590 mph)
    Combat radius: 400-500 km (300-378 nmi, 345-435 mi)
    Ferry range: 3,000 km (1,621 nmi, 1,864 mi)
    Wing loading: 283 kg/m² (58.1 lb/ft²)
    Thrust/weight: 0.58
    1 × 30mm GSh-30-2 cannon externally mounted under fuselage
    1 × 23 mm GSh-23L cannon in remotely controlled tail turret
    Bombs: 7,200 kg (15,873 lb) external stores in six wing bomb bays and eight external pylons (six under wing and two under fuselage)

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