Staff Writer (Updated: 9/17/2016):
Having been based on the An-124, the two aircraft share obvious outward design similarities. However, the An-225 was specifically designed to haul heavy items of note including the rocket boosters of the Soviet space shuttle - known as the "Buran" - a role once undertaken by the large Myasushchev VM-T transport of the 1980s. As such, the An-225 was given six large turbofan engines over that of the An-124's four. Each ZMKB Progress D-18 series engine was rated at 51,600lbs of thrust and provided the necessary lift and transport function required of the heavy-lift aircraft. Like other transports in this class, the An-225 was given a high-mounted flight deck overlooking a short nose cone assembly, a deep tubular fuselage and wide-spanning swept-back wings high-mounted on the fuselage sides. The wings sported noticeable anhedral when viewed in the forward profile and were designed with a high degree of flexibility which was a requirement of the long-spanning assemblies. The aircraft also featured a raised empennage with a unique long-span horizontal tailplane capped at each end by the requisite vertical tail planes. Each of the six engines was fitted to underslung nacelles, three to each wing. The high-mounted nature of the wings assured that clearance of ground activity was addressed. The undercarriage was made retractable in the conventional sense though the main legs consisted of seven double-wheeled heavily-reinforced struts to each fuselage side to manage the aircraft's displacement when at rest. Interestingly, there was no rear access ramp for loading/unloading cargo. Instead, the An-225 made use of a hinged nose-cone that opened upwards to reveal the hold inside.
The completed airframe was first showcased to the West at the Paris Air Show of 1989 and was witnessed in-flight during the Farnborough Air Show of 1990. After the fall of the Soviet Union, the aircraft was removed from operational activities and set in storage during 1994 to which its engines were reconstituted for awaiting An-124 airframes. Accordingly, the Buran shuttle program was retired by this time. The second ordered An-225, now having begun construction, was also retired for the interim. It was only later, when the aircraft fell to the Ukrainian government after the fall of the Soviet Union, that the initial An-225 example was refitted with engines and placed back into an operational status.
As a transport, the An-225 has not disappointed for its cargo hold holds a volume of 1,300m cubed, capable of carrying "super-heavy" loads of several hundred tons. The sheer hauling capability of the aircraft has netted the Antonov product world records and the type has already moved thousands of pallets worth of food and supplies, vehicles (including four main battle tanks and trucks), wind turbines and industrial sized generators to date with its future potential no yet written. The An-225 has seen steady operations with Western countries in support of humanitarian, civilian and military actions worldwide - a sight hardly dreamed of during the height of the Cold War. The sole An-225 in operation is managed by Antonov Airlines - a cargo market hauler with a fleet size of 22 aircraft (2012). The massive aircraft requires a standard crew of 6 to 7 personnel.
The second intended An-225 still remains in a state of construction though this is thought to be well beyond the mid-range point. Of course, cost has stricken the aircraft to a long and arduous road to completion which may or may not be met. Of note with the second example is its redesigned tail section will utilizes a single vertical tail fin and features a rear cargo hold loading ramp accessed powered doors.
September 2016 - It was announced that Antonov and China-based AVIC have partnered up to complete the second An-225 prototype. A first-flight is scheduled for 2019. The experience should bode well for future Chinese large aircraft aspirations - particularly transports and bombers.