Old Antonov, New Engines, New Location

Spot the difference. Among several impressive exhibits from Ukraine, the Antonov An-74 is at the show in duplicate. Look carefully, however. While the An-74TK-200 has its ZMKB Progress/Ivchenko D-36 turbofans in the unusual, but traditional over-wing position, the brand new An-74TK-300 utilizes a more common underslung attachment for its pair of D-436T1s from the same engine manufacturer.

When designed in the early 1970s as a jet replacement for the venerable An-26 twin turboprop, the An-72/74 made use of the Coanda effect to enhance its STOL performance by having jet efflux pass across the upper surface of its generously flapped wing. In the old Soviet empire, the disadvantages of such an installation-ask any Siberian engine maintainer suffering from vertigo-were glossed over.

In today's climate of economic efficiency, Antonov has scored threefold by installing the more fuel-efficient D-436 turbofans; placing them in easier reach of maintenance engineers, whose services are, in any case, less in demand; and using the engines' greater power to decrease the take-off run in spite of loss of the Coanda effect.

This is the international debut of the -300 version, following its maiden flight on April 20. The aircraft was built at Kharkov, home of the KhGAPP, or Kharkov State Aviation Production Enterprise, which has a long history of building Antonov designs. A stretched version, known as the An-174 or An-74TK-400, is also planned, 'TK' indicating convertible passenger/freighter.

By Paul Jackson