A V8 engine is an eight-cylinder V configuration engine with the cylinders mounted on the crankcase in two sets (or banks) of four, with all eight pistons driving a common crankshaft. Most banks are set at a right angle (90°) to each other, some at a narrower angle, with 45°, 60°, and 72° most common.
In its simplest form, the V8 is basically two parallel inline-four engines sharing a common crankshaft. However, this simple configuration, with a flat- or single-plane crankshaft, has the same secondary dynamic imbalance problems as two straight-4s, resulting in vibrations in large engine displacements. Since the 1920s, most V8s have used the somewhat more complex crossplane crankshaft with heavy counterweights to eliminate the vibrations. This results in an engine that is smoother than a V6, while being considerably less expensive than a V12.
Most racing V8s continue to use the single plane crankshaft because it allows faster acceleration and more efficient exhaust system designs.
In 1902, Léon Levavasseur took out a patent on a light but quite powerful gasoline injected V8 engine. He called it the 'Antoinette' after the young daughter of his financial backer. From 1904 he installed this engine in a number of competition speedboats and early aircraft. The aviation pioneer Alberto Santos-Dumont saw one of these boats in Côte d'Azur and decided to try it on his 14-bis aircraft. Its early 24 hp (18 kW) at 1400 rpm version with only 55 kg (121 lb) of weight was interesting, but proved to be underpowered. Santos-Dumont ordered a larger and more powerful version from Levavasseur. He changed its dimensions from the original 80 mm stroke and 80 mm bore to 105 mm stroke and 110 mm bore, obtaining 50 hp (37 kW) with 86 kg (190 lb) of weight, including cooling water. Its power-to-weight ratio was not surpassed for 25 years. Levavasseur eventually produced its own line of V8 equipped aircraft, named Antoinette I to VIII. Hubert Latham piloted the V8 powered Antoinette IV and Antoinette VII in July 1909 on two failed attempts to cross the English Channel. However, in 1910, Latham used the VII with the same engine to become the first in the world to reach an altitude of 3600 feet.Voisin constructed pusher biplanes with Antoinette engines, also, notably the one first flown successfully by Henry Farman in 1908.