The FIRST fLIGHT Bolshoi, Sikorsky 1913

The FIRST fLIGHT Bolshoi, Sikorsky 1913

LTHOUGH the name Sikorsky is generally aassociatcd with the development of the helicopter as a practical flying machine, Sikorsky is also notable as a great designer of Aying boats, and also as the father of the world's first four-engincd aircraft.

The origins of this last title lay in Sikorsky's appointment as head of the Russo-Baltic Vagon Works' design department after he had produced a number of relatively successful biplanes for the Imperial Russian air service.

In the early summer of 1912 Sikorsky was helped by G I Lavrov with the design of the Bolshoi Baltiskii or 'Great Baltic One'. This was a large twin-engines airliner fcaLUring accommodation for seven passengers and crew in a fully enclosed cabin.

The aircraft, which had been nicknamed the 'Tramcar with ''''ings' by the builders, first fly in Marsh 19 I3 on the power of a pair of IOO-hp Argus inline piston engines, though trials immediately showed that the aircraft was hopelessly underpowered.

With the facility of aircraft designers before World war I, Sikorsky merely added another pair of Argus engines on the trailing edges of the lower main planes in line with the first two engines, and driving pusher propellers. Flight trials with this Bolshoi Baltiskii Type B began on May 13, 1913 and soon revealed a marked improvement compared with the original model.

Further improvement was already on the way, however, with the building of another model, the Russki Viryaz or 'Russian Knight'.

This definitive model was slightly larger than its predecessor, and was designed with bombing in mind. Span was increased by 0.5m (19'V3in) from 27.5m (90ft 2% in), the four Argus inlinc engines were now located along the leading edges of the lower wings, driving tractor propellers, and maximum take-off weight had risen by 650kg (14-331b) from 3550 kg\ (7826Ib). The Rllsski Viryaz first flew on July 23, 1913 and on August 8, it stayed in the air for I hour 54 min with eight people on board.

Yet greater things were afoot with the Ilya Mouromets, which was completed in 1913 and first 80wn on December II of that year.

This aircraft spanned some 34-.5m (113ft 2V4in) and had a weight of 4-800 kg (10582Ib). 'otable were auxiliary winglets behind the main planes, a railed promenade deck on the rear fuselage, a large cabin (with sofa, four armchairs and table), a wardrobe, a lavaLOry and cabin lighting and heating.

Details

Type: shon-range transporl

Maker: Russo~BallicWagon \"'orks (RBVZ)

Span: 28m (91 ft lOin)

Length: 19m (62ft 4in)

Height: approx 4 m (13 ft I Y2in)

Wing area: 120 m2 (1292 sq It)

Weight: maximum 4200 kg (92S91b); empty not available

Power plant: rour 100-hp

Argus 4-cylindcr water-cooled inlinc engines

Performance: maximum speed approx 9S km/h

(S9mph) at 1000m (3280 It);