Samurai 777 From Canada, joined Jan 2000, 2451 posts, RR: 5 Reply 3, posted (12 years 11 months 3 weeks 3 days 20 hours ago) and read 887 times:
The Il-86 was originally designed to have a T-tail and four rear-mounted engines, rather like a really fat Il-62. But the Ilyushin Design Bureau realized that there'd be serious weight penalties on that kind of widebody. In other words, a T-tailed Il-86 would've been far too heavy in the rear and thus requiring more powerful and less efficient engines. So Ilyushin decided to make the Il-86's design based on the A300, except that the Il-86 would have four engines.
Boeing did also consider a T-tailed twijet version of the 767 back in the late '70s, but chose the present design for practical reasons.