The cheaper air-cooled version had belt drive to the rear axle, but the dearer water-cooled model had shaft drive.

Separately, I.B.M. also said it would market several new air-cooled versions of its newest line of lower-priced mainframes, which cost up to $450,000.

The engine is either air-cooled or liquid-cooled, but air-cooled versions predominate.

Improvements were made with 6.6% better fuel economy, and nearly 2 decibel (dB) less noise (again vs. the air-cooled version).

The engine was available in either an air-cooled version or a water-cooled version.

In 1913 an air-cooled version was added to the range and in 1914 a kick starter was added.

The Nimbus was further developed into an air-cooled version known as the ADC Airsix which did not enter production and was not flown.

This was an air-cooled version of the Curtiss OX-5, and was intended as an aircraft engine.

It was a belt-fed, automatic weapon that came in both air-cooled and water-cooled versions.

The air-cooled versions were soon relegated to use only in the cheapest versions, and disappeared entirely after 1973 as emissions standards became more stringent.