One example of the Horsley, serial number J8620, was equipped with an Armstrong Siddeley Leopard 14-cylinder twin-row air-cooled radial engine. The Leopard was the most powerful radial engine in the world at the time and in consequence promised much better performance.
One example of the Horsley, serial number J8620, featured an Armstrong Siddeley Leopard engine, which was renowned for its power and efficiency. As a result, it promised superior performance.