«125»
supersonic strategic bomber

    Limited success of the Tu-22 forced the designers to start working on the replacement quite early. One of the options with 'minimal' modification Tu-22M family. Other (project '125') involved radical changes in the design and passed through several stages.
    First variant was a canard missile carrier powered by pair of NK-6 turbojets (or similar NK-10) in the rear fuselage with side air intakes. It was armed with single 4000 kg missile (600 km range), had estimated range 4500...4800 km and speed 2500 km/h. Heavy heat conditions caused wide use of titanium alloys in the airframe. Extensive wind tunnel studies resulted in too optimistic predictions: at Mach 2.0 the '125' had airdynamic quality 6 (12 at subsonic flight) and afterburning(!) fuel consumption of 1.6 kg/kgf/hour required range could be achieved. Later practical experience with the Tu-144 passenger jet revealed that practical fuel consumption better than 1.8...1.9 kg/kgf/hour was unrealistic.
    Some historian have an opinion that '125' canard scheme inspired P.O.Sukhoi to create his T-4 ('100') missile carrier, which will compete later with '125' and Yak-35 in lose-lose-lose contest.
    In addition to missile carrier role, the '125'th could be converted several other military missions:

• Conventional bomber;
• Platform for air-launched ballistic missile;
• Reconnaissater;
• Anti-Submarine aircraft with short reaction time;

    Serious doubts were expressed by military concerning about stability of unusual layout. There is an opinion that not the last role in failure of '125' (and its greater sibling '135') belongs to A.S.Yakovlev - he was pushing his Yak-35 project. Nonetheless A.N.Tupolev KB was trying to solve technical and political problems for few more years... The 60's brought a change in the strategic planning concepts (infamous Khruschiov's ballistic missile bias) and known shortcomings of the American B-58 resulted in cancellation of the '125'. But Tupolev's team could be happy: failure of the project did not resulted in the bureau 'cancellation' (like happened to V.M.Myasichev).
    Anyway, single-regime supersonic bomber concept faded in mid-60's. Variable geometry layout was under development in many countries, and here Tupolev took a lead among Soviet designers... but this is a different story.

References and Credits:

1. «Aviation & cosmonautics» № 9.1999
2. «Bombers» / V.Il'in, M.Levin, 1997 /
3. Aircraft T-4. Myths and realities / I. Bedretdinov /