From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Diagram and explanation of venting passages in an engine core, with notes on Buick's practices.
| Identifier | ExFiles\Box 174\2\ img092 | |
| Date | 27th March 1937 | |
| (sheet 2) quantity, two complete layers of wires being used, one above and one below the ventilating galleries in the larger portion of the core. [Diagram annotations] 5/32" T. 7/16" CORE THICKNESS. LOOSE PIECES - COME AWAY WITH SAND 1/4" CORE THICKNESS 3/4" CORE THICKNESS 3 VENTS - 1/2 DIA GALLERY VENT 3/4 DIA 4 VERTICAL VENTS - 7/16 DIA FLATTENED TO CONTACT 7/16 WIRE [Perspective sketch annotations] TRIGS ON STUD PUT IN LAST The venting passages were made by putting in plugs and wires and then pulling out before baking. The perspective sketch shows how these inter-lock. Wax vents are never used on Buick production. They are considered to be too late in action to be of much real use, and are thought to make a lot of gas them-selves, which has to be driven out of the core. Buick endeavour to arrange a vent out of every sect-ion possible, and avoid localisation of vent pressure by progressively increasing the vent area in proportion to the expected gas flow. The 8 in-line core shown above has a sufficient variety of core thicknesses between barrels to indicate that the only limit is the thickness that the sand will hold up to. We have since heard of an example in production where this is only 1/8". | ||