Do you know {that a} sq. 4 engine was once a factor? The truth is, early designs date again practically 100 years to a person named Edward Turner. He was a bike designer within the UK who penned up a compact engine that basically fused two small twin cylinders right into a single four-pot. He offered the design to an organization known as Aerial Motors, and thus the Aerial Sq. 4 was born.
One would 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 equivalent to an inline-four.
With out getting too technical, this all results in an engine that is inherently well-balanced and smooth-running. Based mostly on the video, it would not sound unhealthy both. And the sq. design makes it supremely compact, basically taking on 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 motorbike for practically 30 years, and sq. 4 engines have been additionally utilized by a couple of different motorbike producers. It made good low-end energy, but it surely 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 high-quality so long as the powerband stayed low within the rev vary. However as motorbike expertise 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 expertise has advanced to the purpose the place a sq. 4 might thrive. However with the world slowly shifting in direction of electrical energy, that is probably an engine design that may exist solely within the historical past books.
