Type 140

Purpose: To improve a German design for a jet bomber.

Design Bureau: OKB-1, formed of German engineers led by Dipl-Ing Brunolf Baade (later replaced by S M Alekseyev), at Podberez’ye.

The EF 140 was begun as a private venture by Baade’s team, who had faith in their forward – swept designs. The weak feature was obvi­ously the need to use six primitive engines, and work went ahead rapidly to replace these by one of the newer engines which by 1947 were available. These were not only much more powerful, so that the aircraft could be­come twin-engined, but also had better fuel economy and much longer and more reliable life. The greater power available meant that previous compromises were no longer nec­essary, and the German team really felt they had a good jet bomber at last. Construction was speeded by using major parts of the sec­ond EF 131, so that the first of two EF 140 pro­totypes began its flight-test programme at Tyopliy Stan on 20th September 1948. The flight report described all aspects of the flight as ‘normal’. Previously, in May 1948, it has been surmised (because of selection of the IL-28 as a production bomber and rejection of the Tupolev Type 78R reconnaissance air­craft) that the EF 131 should be developed as the 140R purely for reconnaissance. This was countermanded in August 1948 by a SovMin decree that the aircraft should be developed as the 140B/R, capable offlying either bomber or reconnaissance missions. By this time the morale of the Germans was poor. They were surrounded by ‘informers’, and still had the status of prisoners. In October 1948 Alek- seyev, whose own OKB had been closed, was appointed Chief Designer of OKB-1. He set about improving things. He drafted in 50 Sovi­et engineers, developed a good relationship with Baade, the informers’ room was taken by the factory chief controller, the control post between Podberez’ye village and Kimry

Dimensions (Type 140) Span Length Wing area	19.4m 19.8m 59.1 nf	63ft7y4in 64 ft m in 636ft2
Weights
Empty	11,900kg	26,235 Ib
Loaded	23 tonnes	50,705 Ib
Performance
Max speed (measured)	904km/h	562 mph
Range	2,000km	1,242 miles

Right: 140 with Nene engines.

was removed, and the Germans were given a better status. As military personnel at Tyopliy Stan objected to the Germans being there, the flight-test programme was moved to the airfield at Borki, which was in any case near­er. The test programme of the 140R (the Ger­manic prefix ‘EF’ tended to be dropped) was opened on 12th October 1949, the pilot being I Ye Fyodorov. It flew again on the following day, but as speed built up wing flutter was ex­perienced. The 140R spent the next nine months shuttling between the factory and the airfield. In July 1950 the second prototype, in B/R configuration, was well advanced in ground testing, and about to fly, when the en­tire programme was terminated.

The 140 differed from the EF 131 principal­ly in having only two engines, of new types. These engines were the imported Rolls – Royce Nene, the Soviet derivative known as the VK-1, and the all-Soviet Mikulin AM-01, also known as the AM-TKRD-1. One Russian account states that the 140 first flew with the Mikulin axial engines, experienced problems,

was re-engined with VK-1 centrifugal engines and was then fitted with wingtip tanks. Pho­tographs show that flight testing was carried out with Nene or VK-1 engines without tip tanks and with the Mikulin engines with tip tanks. Moreover, the British centrifugal en­gine was available in 1947, before the Mikulin engine was cleared for use as sole propulsion (though it had flown under a Tu-2). Despite this, the Soviet record states that on the first flight the engines were the AM-TKRD-1, each rated at 3,300kg (7,275 Ib). Development ofj et fighters was judged to have made the EF 131 armament inadequate, and it was replaced by the outstanding remotely-controlled elec­trically driven turret with twin NS-23 cannon developed for Tupolev heavy bombers. The 140 was armed with two of these turrets, one behind the pressure cabin and the other under the rear fuselage. To share the work­load a fourth crew-member was added, the complement now comprising the pilot at left front with the navigator/bombardier on his right, the dorsal gunner facing aft behind the

pilot and the radio operator behind the navi­gator and controlling the ventral turret. The optical sighting was derived from that of the Tu-4, and in emergency either gunner could manage both turrets. Full armour was re­stored. The capacious bomb bay had electri­cally driven doors and could accommodate various loads up to 4,500kg (9,921 Ib). The fuel system was completely redesigned, with tanks along the top of the fuselage. The 140 suffered from malfunction of the fuel-meter­ing unit on the AM-TKRD-01 engines, which caused engine speed to fluctuate erratically in a way that the pilot could not control, and which could lead to dangerously asymmetric power. After Flight 7 the engines were changed, and OKB-1 flight testing was com­pleted on 24th May 1949.

Type 140R

To achieve the necessary range, this aircraft was (the Soviet record states) fitted with ‘newer, more economical’ VK-1 engines de­rived by V Ya Klimov from the Rolls-Royce Nene, even though these were rated at only 2,700kg (5,952 Ib). The span was increased, and fixed tanks were added on the wingtips, increasing internal fuel capacity to 14,000 litres (3,080 Imperial gallons). The former bomb bay was redesigned to carry a wide as­sortment of reconnaissance cameras, as well as high-power flares and flash bombs in the forward bay and in the fuselage tail.

Type 140B/R

Never completed, this aircraft was intended to have an improved fire control system, the
crew reduced to three, and to have a range of 3,000km (1,864 miles) at 12,000m (39,370ft) carrying 1.5 tonnes (3,3071b) of bombs and 9,400 litres (2,068 Imperial gallons) of fuel.

Always handicapped politically by their an­cestry, these aircraft were merely an insur­ance against failure of the first Soviet jet bombers such as Ilyushin’s IL-22 and Tupolev’s Tu-12. They were finally killed by inability to solve the structural problems of the forward – swept wing.

Dimensions (Type 140R) Span Length Wing area	21.9m 19.8m 59.1 nf	71 ft 1014 in 64 ft 11)4 in 636ft2
Weights Notrecorded
Performance
Max speed (measured) Range at a cruising altitude	866km/h	538mph
of 14, 100m (46,260ft)	3,600 km	2,237 miles

Left: 140B/RwithAM-01 engines.

140B/RwithAM-01 engines