
Do you know {that a} sq. 4 engine was a factor? In actual fact, early designs date again almost 100 years to a person named Edward Turner. He was a bike designer within the UK who penned up a compact engine that primarily fused two small twin cylinders right into a single four-pot. He bought the design to an organization referred to as Aerial Motors, and thus the Aerial Sq. 4 was born.
One does not merely stick a few inline twins collectively for a four-banger. As this video from the YouTube channel Driving 4 Solutions demonstrates, this engine is actually a sq. form with the cylinders pointing straight right down to the crankshafts. Sure, that is crankshafts—the design makes use of two counter-rotating crankshafts linked with geared flywheels. The cranks path one another by 180 levels, and the pistons are diagonally matched. This leads to a firing order an identical to an inline-four.
With out getting too technical, this all results in an engine that is inherently well-balanced and smooth-running. Primarily based on the video, it does not sound unhealthy both. And the sq. design makes it supremely compact, primarily taking over the identical area usually occupied by a V-twin or perhaps a massive single-cylinder mill.
The sq. 4 engine wasn’t only a flash within the pan. Aerial Motors constructed the Sq. 4 bike for almost 30 years, and sq. 4 engines had been additionally utilized by a number of different bike producers. It made good low-end energy, however it was an costly engine for the time, and it suffered from overheating points.
There was additionally treasured little room to have a thriving consumption system to feed the engine, which was advantageous so long as the powerband stayed low within the rev vary. However as bike know-how advanced to small, high-RPM engines, the low-speed sq. 4 simply could not sustain. Aerial ended manufacturing of the Sq. 4 in 1959.
The video notes that know-how has advanced to the purpose the place a sq. 4 may thrive. However with the world slowly transferring in direction of electrical energy, that is seemingly an engine design that can exist solely within the historical past books.