History chewed out and spat out some incredible aeroplanes. We drag these rotting morsels out of the compost mulch of history and drag them to our laboratory/fight-club for autopsy. To assist us in our morbid analysis is Hush-Kit’s tamed scientist and engineer Jim ‘Sonic’ Smith (a key figure in the Typhoon and UK JSF programmes among others). To further our thrills we shall pit these dead aeroplanes against each other!

This comparison showcases two outrageously ambitious supersonic bomber concepts, the US B-70 Valkyrie and the Myasishchev 103-M from the Soviet Union. Designing any long-range aircraft to fly at sustained supersonic speeds is a challenging exercise, and most such aircraft have really been designed with a supersonic dash capability, rather having a long-range supersonic cruise capability. The two aircraft considered here date from the 1960s, with the Myasishchev M-50 having less ambitious performance goals than the XB-70A, which was a bold and unsuccessful attempt to replace the B-52 with an aircraft capable of cruising at Mach 3.

Myasishchev M-50

The M-50 was a delta-winged bomber, which first flew in October 1959. The aircraft caused a sensation with its appearance at the 1961 Soviet Aviation Day fly-past at Tushino. With an approximate loaded weight of 320,000 lb, the M-50 was intended to cruise at subsonic speeds, but was capable of a supersonic dash at speeds up to about Mach 1.5. The propulsion system consisted of four podded engines. The inboard pair were mounted on pylons at about the mid-point of each wing, and were fitted with afterburners. The outer pair of engines had no afterburners, and were carried on the extreme wing tip.

The aircraft had a delta wing and a low-set tailplane which have been described as generically similar to a scaled-up MiG 21. While this may be true for the planform shapes, the overall appearance is quite different, and extremely imposing, and ‘futuristic giant bomber’ is what springs to mind.

While appearing extremely spectacular, the M-50 was intended to be further developed into service, the production version to be the Myasishchev M-52. The various reference sources available quote a wide variety of performance figures, but, as it is believed the prototype made only 19 flights, I would conclude that performance was disappointing. This would have been at least partly due to the unavailability of the 40,765 lb thrust Zubets RD-16 engines proposed for the production aircraft, and their substitution with Dobrynin RD-7 engines of 35,275 lb thrust (afterburning) and 20,945 lb thrust (dry).

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The M-50/M-52 programme was cancelled, with the Tushino appearance of the aircraft in 1962 being the final flight of the M-50 prototype, and the M-52 not proceeding to flight test. As with most of the major powers, a combination of issues, including the vulnerability of manned strategic bombers; advances in the capability of ballistic missiles; and the development of submarine-based nuclear deterrent strategies lead to the cancellation of the programme.

North American XB-70A Valkyrie

Even today, nearly 60 years after the first flight of the Valkyrie, on Sept 21, 1964, the performance aspirations for the aircraft seem incredible. The intention was to replace the B-52 with an aircraft cruising at Mach 3.0 at 70 – 80,000 ft with an unrefuelled range of 7500 miles. The airframe to deliver this performance was an astonishingly beautiful slender canard delta, powered by no less than 6 General Electric YJ-93 engines, each delivering about 19,500 lb thrust dry, or 31,000 lb in afterburner.

The engines were carried in a wedge-shaped common nacelle forming the fuselage below the wing, while above the wing a slender circular fuselage extended ahead of the wing, carrying the crew compartment and canard. The lower fuselage was shaped so that, in combination with the folded down outer wing, lift could be gained through the shockwaves generated by the aircraft at its Mach 3.0 cruise speed. This arrangement also reduced trim drag, and increased lateral and directional stability at high speed. The wing planform was a pure triangle, with 65 ½ degrees leading edge sweep and a straight trailing edge.

Because of the high cruise speed envisaged for the aircraft, the structure of the Valkyrie was largely stainless steel, with extensive use of honeycomb panels, and some use of titanium. Stainless steel honeycomb structures have proved to be troublesome in other applications, and significant electrolytic corrosion was found at a late stage in the construction of the first aircraft, requiring a partial re-build.

During the development of the aircraft, parallel developments in Inter-Continental Ballistic Missile (ICBM) technology and concerns about the effectiveness of surface to air missiles against even the fast and high-flying XB-70A, resulted in President Kennedy declaring in March 1961 that America’s forthcoming missile capability “makes unnecessary and economically unjustifiable the development of the B-70 as a weapon system at this time”. The effort was reduced to two aircraft, which would deliver a programme of research into high-speed flight, and would retain a capability to be developed as a weapon system if necessary.

The aircraft proved capable of achieving its design cruise speed of Mach 3.0, although the lateral and directional behaviour of the first aircraft was unsatisfactory at high speed, and it was eventually limited to a maximum speed of Mach 2.5. The second aircraft was built with a dihedral of 5 deg rather than the slight anhedral of the first aircraft, and this change resolved the high-speed stability problems. Unfortunately, the second aircraft was lost in a mid-air collision on 8 June 1966.

Myasishchev M-50 ‘Bounder’ and North American XB-70A Valkyrie Assessment
Two spectacular-looking supersonic bombers, one Soviet, one American. Both aircraft were ultimately unsuccessful in being developed into operationally useful capability, with the M-50 making only 19 flights, and the XB-70A requiring significant redesign to cure lateral-directional stability issues.
No air combat comparison is presented. The M-50 appears to have been a failure. The XB-70A demonstrated very impressive high-speed cruise capability, but was not developed as a weapon system.
That said, it is an easy decision to make on which of these was the better aircraft. The M-50 never got to fly with the planned production engine, and some reports question whether it was even able to fly at supersonic speeds. The XB-70A was able to demonstrate sustained flight at just over Mach 3, and performed valuable service for NASA in aerodynamic and sonic boom trials.

Both aircraft looked extremely futuristic, and particularly impressive in flight, but the XB-70A Valkyrie gets my vote as the better loser, as it came much closer to its design objectives. The requirements for both aircraft were essentially overtaken by events, as their intended strategic nuclear strike role passed into the realm of the ICBM, whether land-based or submarine-launched.
 

KEEP THIS SITE GOING BY SUPPORTING US ON PATREON The Hush-Kit Book of Warplanes will feature the finest cuts from this site along with exclusive new articles, explosive photography and gorgeous bespoke illustrations. Pre-order The Hush-Kit Book of Warplanes here. Thank you. Our controversial merchandise shop is here and our Twitter account here @Hush_Kit. Sign up for our newsletter here. The Hush-Kit Book of Warplanes will feature the finest cuts from this site along with exclusive new articles, explosive photography and gorgeous bespoke illustrations. Pre-order The Hush-Kit Book of Warplanes here.