02 October 2009

One of the unique features of the Ilyushin Il-62 jetliner was the twin wheel telescoping strut that retracted vertically into the aft fuselage to keep the aircraft from tipping on its tail when parked or taxiing in an unloaded condition.

The reason that the Il-62 can tip on its tail easily was done for aerodynamic reasons. Unlike most aircraft that have the main landing gears aft of the empty and loaded center of gravity, the Il-62's main landing gears are behind the aircraft's loaded center of gravity but ahead of the unloaded center of gravity. This results in the need for a lower nose up pitching moment at takeoff when the aircraft is loaded as the pivot point at rotation (the main landing gears) are closer to the loaded center of gravity than what would normally be the case for most aircraft.

As a result, the horizontal tail area could be reduced which resulted in weight savings and reduced drag in cruise flight. The Vickers VC-10 by comparison had a large horizontal tail area of 645.9 square feet compared to the Ilyushin Il-62's at 430.6 square feet.

Source: OKB Ilyushin: A History of the Design Bureau and Its Aircraft by Yefim Gordon, Dmitriy Komissarov and Sergey Komissarov. Midland Publishing, 2004, p255.

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