FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1950
1950 - 2042.PDF
tal installation of two Darts in a Wellington test bed. DEVELOPMENT OFTHE TURBOPROP Two Darts are installed in this experimental Dakota. Two such freighters are to be tried out by B.E.A. on its internal routes. (Continued from page 491) quently a double power-failure. Apparently, in view of current Naval aircraft designs, to be referred to below, this risk is not rated very highly. Perhaps it should be explained that in a coupled unit such as the Proteus both units drive the contra-gearbox, through a single common shaft, and in the event of a failure of one, the other drives both blade banks of the contraprop. The inoperative turbine must be isolated mechanically by means of a clutch or free wheeL With a " Siamese-twin " unit such as the Double Mamba, each unit drives one of the contra-rotating co-axial airscrews quite independently, although the gear trains are in a common casing. If either unit fails one airscrew is feathered and the other continues to operate under the power of one Mamba. This consti- tutes one of the main differences between the power instal- lations of the Brabazon and the Type 167 Mk II. The Centaurus piston engines of the Prototype are arranged as double units operating quite separately but mounted in pairs. The Proteus pairs are, on the other hand, coupled. The coupled Proteus has run on the beds but has not Outstanding among turboprop designs is the handsome Viscount 700 airliner powered with four Rolls-Royce Darts. yet been tested in the air. Flight testing will most prob- ably be carried out in the actual aircraft for which the units were designed. Power output is exactly double that of the .single Proteus. To disengage one unit a hydraulically operated dog clutch is fitted between its turbine shaft and main driving pinion. Latest addition to Armstrong Siddeley's turboprops is the Double Mamba, which powers the Blackburn and Fairey anti-submarine machines. These aircraft cruise economi- cally with either one of their Mambas stopped and its air- screw feathered. The weight of the double unit is 2,000 lb and its combined take-off rating 2,040 s.h.p. plus 810 lb thrust. Still in its experimental stages and at present set aside to allow its designers to concentrate on other types of units, is the Napier Coupled Naiad. It produces 2,970 s.h.p. and 480 lb thrust for a weight of 2,550 lb. Twin free-wheel mechanisms are incorporated in the duplex two-stage reduction gear. In America, justifiable pride in the latest piston engines, together with well-filled order books and a firm belief in various arrangements of exhaust turbo-superchargers upon A Lincoln se/Ves as the flying test-bed for the Napier Naiac< in its nose.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
