The Chaise 4B is an aircraft engine designed and built in France during the 1930s, unusual in being an inverted air-cooled 14º V-4.
During the early 1930s Societe Anonyme Omnium Metallurgique et Industriel / Etablissements Chaise et Cie, commonly known as Moteurs Chaise, designed and produced a compact lightweight four-cylinder aircraft engine developing 130–155 hp (97–116 kW).
To reduce overall dimensions and length of crankshaft Chaise designed an inverted V-4 with a very small vee angle of 14º.
[1] The light alloy (R.R.50) crankcase supported the major components of the engine.
Accessories were mounted at the rear with magnetos driven by camshafts running either side of the crankcase, which also operated the valves by pushrods and rocker arms with triple concentric return springs.