Editing Bristol Aquila (section)

==Design and development==
The Aquila was developed two years after the somewhat larger [[Bristol Perseus|Perseus]], both being [[sleeve valve]] designs. The primary difference was in size, the Perseus being based on the {{convert|5.75|by|6.5|in|mm|abbr=on}} cylinder used in the [[Bristol Mercury|Mercury]] engine, while the Aquila used a new and smaller {{convert|5|by|5.375|in|mm|abbr=on}} sized cylinder. The result was a reduction in [[engine displacement|displacement]] from 1520 to 950 cubic inches (24.9 to 15.6 L).

The first Aquila engine delivered a modest {{convert|365|hp|kW|lk=on}}, which was unspectacular for an engine of this size. It soon developed into more powerful versions as improvements were worked into the line (as well as similar changes to the Perseus), and by 1936 it had improved to {{convert|500|hp|kW|abbr=on}}. This would have made it an excellent replacement for the [[Bristol Jupiter]], which ended production at {{convert|590|hp|kW|abbr=on}} three years earlier, but by this time almost all interest was on ever-larger engines.