FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1950
1950 - 0822.PDF
536 FLIGHT, 27 April 1950 CABIN COMFORT LAID ON Details of the Godfrey Ground- Conditioning Truck for Aircraft The new Godfrey ground- conditioning truck is here shown connected to a B.O.A.C. Canadair Four. ANYONE who has ever had occasion to sit in an air- /% craft on a tropical airfield will know very well how •*- -*• uncomfortable an experience it can often be. Despite the wall and roof insulation with which most modern aircraft are equipped, the cabin rapidly takes on the thermal characteristics of a ham-mam. In order to mitigate this effect, ground-conditioning equipment of various kinds has been devised. As in the tropics aircraft interiors need cooling whilst on the ground, so conversely, in arctic conditions static heating is required. (The use of the adjective "arctic" is a convenience, for whilst in Great Britain the winters can be chilly enough, in Canada, the U.S.A. and Scan- dinavia, for example, temperatures below freezing are seasonally the rule rather than the exception.) In addi- tion to the business of heating or cooling the interior of the aircraft whilst at rest, the increasing use of cabin pressuri- zation makes necessary the routine check-testing of the pressurizing equipment and, of course, the pressure- retention capacity of the structure. In collaboration with B.O.A.C., a universal ground- conditioning unit has been designed and manufactured by Sir George Godfrey and Partners, Ltd., Feltham. Middle- sex, so far as we are aware, it is the only unit in the world that is capable of fulfilling, at need, all the demands of aircraft ground-conditioning and pressure-testing, irrespec- tive of climatic extremes. The comprehensiveness of such a performance is rendered possible only by the use of air as the working medium. As may be seen from the heading photograph, the unit is a compact, pneumatic-tyred truck—which, being only 5ft yin high, 5ft ioin wide and 10ft 6in long, is readily INTAKE 5IIENCER I 1 I I AIR INTAKE "PRESSURE GAUGE J^l.i OEUVEfff 10 CABIN The flow-paths through the unit for the various conditioning funrtions can readily be followed in this schematic diagram. capable of transport by ah—and is made ready for use simply by connecting the flexible duct of lagged canvas between the ground-conditioning connection on the aircraft and the appropriate delivery outlet on the truck. Power for driving the unit's Roots-type Marshall blower is derived from a Rolls-Royce B80 straight-eight engine, which develops 150 b.h.p. at 3,000 r.p.m. Torque is transmitted through a Borg and Beck clutch and a flexible coupling, and the engine is complete with 12-volt dynamo and starter motor, air filter and ignition screening. Inducted air, having passed through the intake silencer, compressor and delivery silencer, is led past a pressure- return valve (which protects the compressor and ducts) to a choke valve which, by varying back-pressure, can be used to regulate temperature. Thence, the air is delivered through the primary cooler, downstream of which it is either directed through the air-cycle turbine cold-air unit or permitted to by-pass that unit, according to the function required. There are two branches in the delivery, one of which, furnished with a spill-valve, non-return valve, B.S.I, nozzle, manometer, thermometer and pressure- gauge, is used for pressurization testing, whilst the other branch, in which are incorporated a water separator and a thermometer, is used either for heating or cooling the cabin; the branch not in use is sealed-off by a blanking cover at the delivery port. If the aircraft cabin requires to be heated, the cooling fan is disengaged by means of a clutch and the choke valve partially closed, whilst the control valve will be opened so as to by-pass the cold-air unit. The maximum heating delivery in this condition is 200,000 B.T.U.s/hr. When cooling is required, the choke valve is opened, the cooling fan engaged, and the control valve closed so as to bring the cold-air unit into the circuit. Between the compressor of the cold-air unit and the turbine, the air is ducted through a secondary cooler, so that, in expanding through the turbine, its temperature is very considerably reduced. Temperature can, in fact,, be reduced from an intake ambient of 120 deg F. down to a delivery temperature of yj deg F., the flow volume being 1,500 cu ft/min. The pressure-testing capacity of the unit is up to a differential of 12 lb /sq in for an aircraft cabin of Brabazon size. On Thursday, April 20th, a demonstration of the Godfrey truck's conditioning capabilities was given at London Airport, a B.O.A.C. Canadair Four serving as the " conditionee." A large number of people, including high pranking officers and engineers of B.O.A.C., B.E.A. and -'many of the foreign operating companies, witnessed a verv impressive display. Immediately following the demon stration, the truck was despatched in a York freighter aircraft to Calcutta, where it is to be tested by B.O.A.C. 011 incoming and outgoing aircraft. • r
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
