The T-4 bomber, also known by various names such as Aircraft 100, Project 100, and Sotka, was Sukhoi’s response to the challenge of creating an aircraft capable of sustained speeds over Mach 3.

Sukhoi’s design won out in a Soviet contest due to its high-speed specifications.

Developed with over 600 patents and new inventions, the engineering of the T-4 represented a significant leap in military aviation technology.

One of the striking features of the T-4 was its fly-by-wire control system, with a mechanical backup in case of failure.

Its unique design included a droop-nose configuration for improved pilot visibility during landing, similar to that of the Concorde, and the use of parachutes to decelerate upon touchdown.

Unlike the Concorde, however, when in flight, the T-4’s nose could not be lowered, so a periscope was installed to assist the pilot—usable only at speeds up to 600 km/h.

Despite being built to reach Mach 3 and an altitude of 24,000 meters, the T-4, propelled by four Kolesov RD36-41 engines, achieved a maximum speed of only Mach 1.3 during its testing phase.

Ten hours and twenty minutes of flight over ten separate occasions were all the 101 prototype would experience before the project’s termination.

The reasons for the cancellation of the T-4 program were multifaceted.

The changing military landscape, where ICBMs and advanced anti-air missile systems rendered high-speed, high-altitude bombers less viable, played a significant role.

Additionally, internal politics within the Soviet defense hierarchy influenced the project’s demise, with reports suggesting that the T-4 was scrapped to secure an extensive MiG-23 order.

Although the United States retired the XB-70 in 1969, the Soviets continued their T-4 development until it was finally canceled by the Moscow Aviation Institute in 1974, leaving three additional prototypes unfinished.

Despite never achieving its intended performance targets, the T-4’s technological advancements were not in vain.

The program’s innovations contributed to subsequent Soviet aircraft designs, influencing the development of bombers like the Tu-160, which benefited from the lessons learned during the T-4’s short-lived flight test period.

Today, Russia is refurbishing its remaining Tu-160s for new missions. Following the path set by the United States, however, Russia is also investigating the potential for stealth.