FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1945
1945 - 2384.PDF
DECEMBER OTH, 1945 FLIGHT 597 Bristol Theseus I Qas Turbine/Airscrew Unit of High Power and Low Consumption : Separate Drives for Airscrew and Compressor The air intake to the compressorsurrounds the reduction gear, with the electric starters on each side andthe shallow oil sump beneath. SINCE the inception of the gas turbine for jet propulsiona considerable amount has been heard of the possibleuse of such a unit as a prime mover to drive a conventional airscrew; in fact, it would not be unfair to say that a weighty body of enlightened opinion holds the view that this combination is likely to prove of much greater overall value than jet propulsion itself. There are very many aspects peculiar to a combination of this nature which render it particularly attractive as an alternative to the piston engine in the medium- and higher- power categories. Jet propulsion cannot truly be regarded as being in direct opposition to the piston engine (except iiu certain specialised instances), due to the fact that its form of operation is almost the direct antithesis of the conventional i.e. engine. The turbine/airscrew combination is, however, much more than a serious adversary to the piston engine in that it id capable of severely competitive fuel consumption, whilst having the additional advantages of long period-, between overhauls, efficiency of propulsion over a widenir >ge, low overall diameter and almost vibrationless lunning. • hat the Bristol Aeroplane Company have been develop- ing this type of engine and that the first fruits of their labour, the Theseus I, has been crowned with success" is a very good sign for the future, and further developments will obviously be awaited with the greatest interest. The Theseus I consists of a compound multi-stage com- pressor which inspires air through an annular orifice around the airscrew reduction gear, the compressed air then being delivered through a heat exchanger before passing to the combustion chamber, where its temperature is further raised by the burning of injected fuel. The resulting pro- ducts of combustion pass to a turbine by means of which the compressor and auxiliaries are driven, and thence to a further turbine stage which, through a forward extension shaft, drives the airscrew. After leaving the latter turbine the gases pass through the heat exchanger, where they give up a measure of their heat to the compressed air on its way to the combustion chambers. From the heat exchanger the exhaust gases are finally discharged through a con- trollable nozzle, so providing a certain proportion of the total thrust. A feature of all turbines is that they have the inherent quality of optimum efficiency at maximum speed, and, consequently, when considering driving an airscrew by means of a gas turbine the very real problem of obtaining flexibility presents itself. It is also true that a turbine
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
