U.S. Patent Specifications

In an aircraft, a plurality of internal combustion engines each having an exhaust manifold and operated at substantially the same speeds, propellers connected to said engines having their pitches so adjusted that the engines may bo operated at the same speeds and each develop the same driving power, and means comprising a direct gas connection between the manifolds of said engines subjected only to the pressures caused by the engine exhaust gases operating against the friction of the exhaust conduit for so equalising the back pressures on the cylinders of the engines as to exert a force tending to hold the engines in synchronism and ensure alternate explosions.