FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1938
1938 - 1779.PDF
JUNE 23, 1938. FLIGHT. THE GIPSY TWELVE REVEALED 1i IHANKSHAFT CENTRE BEARING FORKED "." •; CONNECTING ,:.ROD ASSEMBLY HYDRAULIC CONTROL TO MAGNETOS & AIRSCREW GOVERNOR INDUCTION PIPE mum take-off conditions on the brake (525 h.p. at 2,600 r.p.m. at + 3Jib. boost); 4 hours under minimum take off conditions (510 h.p. at 2,400 r.p.m. and + 3^1b. boost); and, finally, a one-hour high-speed test with the engine racinga t 2,575 r.p.m. under very light load. The cylinder heads are aluminium alloy castings held to the barrels by four high-tensile steel studs apiece screwed at their upper ends to the crankcase. A copper-asbestos washer fitting into a recess of the head makes the joint between the head and the cylinder. Flanged bronze guides for one inlet and one exhaust valve are fitted, the high expansion steel seatings being shrunk and peened into position in the cylinder head. In each side of the cylinder head there is fitted a 14 mm. sparking plug. Carbon steel forgings, machined externally to form cool- ing fins, and ground internally, form the cylinders. Pro- tection is given against corrosion. The cylinder barrel is spigoted into the head, the joint being made by a copper- The D.H. Gipsy Twelve, shown here in part section by Max Millar, is Britain's representative in the inverted vee-twelve air-cooled class. It is the first of its type in the world to go into production, and powers the De Havilland Albatross and Don iiii asbestos washer. The other end of the barrel fits into the crankcase to the extent of its flange; an oil-tight joint is formed by a Dermatine ring between the radius of the flange and the chamfered edge of the crankcase bore. The pistons are machined from up-set forgings oi aluminium alloy They are of the slipper type and are so designed that the stress from the crown is taken directly to the gudgeon pin which floats in both the piston and the small end of the connecting rod and is retained bv external circlips and washers at each end. Each piston has three rings, the inner one being a scraper, which after scraping oil from the cylinder wall deflects it through a series of small drilled holes to the inside of the piston and thence back to the crankcase. Connecting rods are of H-section and are machined all over from forgings of 65-ton nickel-chrome steel. The
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
