The
Blackburne Tomtit engine was developed from Blackburne's motorcycle engines. The first one adapted to aircraft use was the best performing engine at the
Lympne light aircraft trials of 1923, despite its lack of refinement. The Tomtit was a modified version of the Lympne 696 cc V-twin, marketed specifically for flight. The Tomtit could run upright or inverted and was the first British engine to fly inverted, in the
ANEC I. The inverted configuration was more common, but the
Avro 558 used it in the upright arrangement, and the
Avro 560 flew with both upright and inverted Tomtits. ==Applications (including early Lympne 1923 version)==