Aspin (UK); Briggs (US)

F. M. Aspin and Company, Ltd. of Bury, Lancashire, UK announced a new Aspin engine design in 1937. The unique feature was a combustion chamber of conical shape for each cylinder. Inside the conical opening in the cylinder head was a thin rotating cone (like an empty ice cream cone) driven by a gear attached to the apex of the cone at the top of each cylinder. The open interior of this rotating thin conical surface was the combustion chamber. The rotating conical surface, itself, had eccentric openings which covered and uncovered, in proper sequence, the intake and exhaust ducts, and the dual spark plugs. Thus the Aspin engines had a conical sleeve valve rotating within a conical combustion chamber. The basic concept was tested in a single-cylinder experimental engine before Aspin developed the HOAE designs described below. Briggs Manufacturing Corporation of Detroit, Michigan obtained the US rights for the Aspin patents in 1938. Briggs was listed later (Ae42) as offering the second version below of the O-106. The US entry into WWII put an end to Briggs' plans for the engine.

O-106 -- {3.268 / 3.150 / 105.7} / {83 / 80 / 1731}

4cyl; Flat-Four; 80hp@5000rpm; 1937; Wt = 150#.
Dual-ignition engine; geared to 0.5. This first version apparently had a two-throw crankshaft with the front and rear cylinder centerlines on each side aligned. This led to the opposing cylinders moving in the same direction at the same time, thus giving rise to large vibrational couples, even in a four-cylinder engine, similar to those experienced by the two-cylinder Lawrance A-3 (C-2).
Applications: None found.

4cyl; Flat-Four; 80hp@5000rpm; 1938-1941; Wt = 170#.
Dual-ignition engine; geared to 0.5 or 0.4. This second version had a three-throw crankshaft with the front and rear cylinder centerlines on each side offset as in most HOAE. This led to the opposing cylinders moving simultaneously toward and away from each other in the boxer configuration, thus eliminating the large vibrational couples of the first version. Apparently, this is the version for which Briggs acquired rights.
Ae39, Ae42; J41toJ42.
Applications: None found.

O-200 -- {4.625 / 3.0 / 201.6} / {117.5 / 76.2 / 3304}

4cyl; Flat-Four; 100hp@2500rpm, 114@2800 (TO); 1944-1946; Wt = 200#.
Dual-ignition, ungeared engine with a four-throw crankshaft.
Applications: None found.


Updated 4/4/04