. OOS Stal’-5

Purpose: Flying-wing transport or bomber. Design Bureau: OOS, Russian for Section for Experimental Aeroplane Construction, Moscow Tushino.

Along with Kozlov (see ‘invisible aircraft’ story) the chief designer at OOS was Alek­sandr Ivanovich Putilov, who joined from CAHI (TsAGI) when OOS was just a group in­
terested in steel airframes. The Stal’ (steel) 5 was sketched in 1933 in two forms, as a trans­port and also as the KhB (Khimicheskii Boye – vik), an attack aircraft for spraying poison gas (obviously it could also carry bombs). In 1934 a complete wing spar was made for static test, and in late 1935 VVKarpov and Ya G Paul actually flight-tested a scale model with a span of 6m (19ft 7in), wing area of
15.0m2 (161.5ft2) and two 45hp Salmson en­gines. It was difficult to fly, and the idea was dropped.

Putilov’s flying wing was to be powered by two 750hp M-34F water-cooled V-12 engines. The structure was to have been almost en­tirely Enerzh-6 stainless steel, skinned with Bakelite-bonded veneer over the centre sec­tion and fabric elsewhere. The drawing shows the slotted flaps, elevator and four re­tractable wheels. The payload was to have been between the spars in the centroplan (centre wing), deep enough for people to walk upright.

Several designers, notably the American Burnelli, tried to make extra-efficient aircraft along these lines. None succeeded.

Dimensions

Span 23.0m 75 ft 5Л in

Length 12.5m 41ft

Wing area 120nf l,292ft!

Weights (estimated)

Empty 5.5 tonnes 12,125 Ib

Loaded 8 tonnes 17,640 Ib

No other data.