Su-24BM (Big Modification)

[overscan]

The first project of the radically improved Su-24BM ("large modification") began in 1979. V. Marov was assigned chief designer. The aircraft considerably grew in size, it became wider (between the engines were placed internal armament) and even more resembled the F-111. Its classic "Sukhoi" air intakes were shortened, and now their leading edges were located under roots of wing as on the F-111. Engines were probably to be Al-31F turbofans. However, some doubts arose about the effect of the increased mass on the wing hinge structures.

Meanwhile in Sukhoi OKB profound changes occurred. In 1982 the head of Aviaprom, Ivan Silayev, removed Yevgeny Ivanov from the post of design project leader of Sukhoi in favour of Mikhail Simonov, who was the firm supporter of the expensive and long-term T -60S program for the creation of the fundamentally new "medium-size strategic aircraft" (the second design with this name). If successful, this fourth generation design would have definite advantages over any third generation aircraft like the Su-24.

Design of the T-60S (under another designation) was begun in TsAGI in the 1970s on the technical base of the Sukhoi T-4MS. Ex-Sukhoi designer (and friend of Ivanov) Oleg Samoylovich has said that, while largely the same as T-4MS in basic design, some features of this TsAGI aircraft was somewhat odd; the engines were proposed to be "dual-flow" where a single fan fed two separate engine cores, while the swing-wings were supposed to pivot right back to rest under the fuselage.

This project was transferred by Simonov (before he became head of Sukhoi, in his old job at the aircraft ministry) to Sukhoi in 1981. This took effort away from the Su-24BM project.

The supporters of development Su-24 then undertook an audacious step - the potentially troublesome variable geometry wing of the Su-24BM was substituted with fixed wings, the aircraft obtained the twin endplate fins, and the radio-electronic equipment, taken from the project T-60S. In 1983 a full-scale mock-up of this Su-24 based machine was built, but under pressure from Simonov and Silayev all work on this machine was stopped, ostensibly to accelerate work on the T-60S. T-60S program funding was ended by Yeltsin's order in 1992, though work on it is thought to have continued at a slow pace since.

http://www.airwar.ru/enc/bomber/su24m.html
http://www.sergib.agava.ru/russia/sukhoi/t/60/t60.htm