FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1937
1937 - 0923.PDF
1937- •THIGH tb FEET- •--— • ' • i LAYERS OF -= ASBESTOS BLANKET HELD IN PLACE BY__ " CHICKEN WIRE N^. \W -* '• ' ^^N. - \, \. S^ '* -==\ FINE-MESH WIRE SCREEN TO KEEP \ OUT BIRDS * -z%sr~-:"® \ \ N it i CARDAN SHAFT 2z~£d5X PITOT HEAD PERFORATE! ASBESTOS St COVERING GL WOOL PADDI wnoN DEPRESSION BOX FOR ALTITUDE RUNNING CARDAN SHAFT HAS LAMINATED STEEL FLEXIBLE JOINTS completely equipped, sound proofed experimental engine test house ; and at present under construction at Coventry Municipal aerodrome, a few miles from the works, two rather less elaborate production test beds, with room for several more. The single-cylinder test shop under the main works and beside the despatch department contains a test bed in miniature in all the essentials—dynamometer, air-cooling fan and silencing—while the thermometers, consumption and pressure gauges, tachometer, etc., are on a centralised control panel. The supercharger test is of the latest design, and is most comprehensive. Blower and accessories are driven through Hardy flexible disc couplings by a motor with a safety overspeed governor. A dynamometer with double-acting weighing gear indicates the torque and horsepower absorbed for either rotation. The air intake into a large surge tank is via a venturi and valve controlled from the panel, which allow accurate adjustment and readings of airflow and alti tude depressions. The mixture pressures in the volute and leaving the induction casing for the outlet surge tank can also be observed. Oil inlet and outlet temperatures and pressures are recorded, together with consumption, and lastly generator, starter, petrol pumps, etc., and their driv ing gears are run in and tested. The main test house at the works is very complete and in every way modern. The building, which was con structed in co-operation with the N.P.L., using sound- absorbing material wherever possible, is double throughout, with a cavity between the two walls, and separate founda- SPRING-DAMPED ENGINE MOUNTING PLATE tions. The inside walls are lined with asbestos wool and perforated asbestos sheet, and the floor is insulated from them with cork. A long, silenced tunnel leads away the exhaust gases and cooling air, reducing the noise of an engine running at full speed—which at close quarters would be painful to the ears—to a muffled, distant rumble. During the installa tion or removal of an engine a roll partition shuts off this tunnel from the main house. The cooling air intake through the roof is also silenced. All controls, switches and instruments are collected in the control room beside the engine, and, due to the use of asbestos and glass wool for the walls, it is possible to talk in the room not three yards from where the engine is running. The engine mounting is so arranged that all torque is taken on a rear flexible support and by two large springs holding the sides of the mounting plate. These features, which may be seen in the illustration, prevent any possible damage to the lugs on the engine. The whole mounting unit is on wheels to allow any size of engine to be tested and to be readily accessible. Normally the wheels are slightly raised from the track by four jacks. A canvas section in front of the engine allows the cooling tunnel to be extended right up to the cylinders or drawn back out of the way for examination of the front engine components. The wind tunnel has a gauze at the top where air is drawn in between the two roofs. Air speed is controlled by varying a large butterfly valve and by alter ing the current of the 550 h.p. electric motor which drives the fan. Speeds up to 170 m.p.h. can be produced in the tunnel and as high as 200 m.p.h. round the cylinders.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
