Originally Posted by
Allan Lupton
The DH53 Hummingbird was designed for the same Lympne Light Aircraft Trials in 1923 as the EE Wren. I think the prototype had a 750cc Douglas engine but can't easily find its power. There is a story that Geoffrey de Havilland was flying it home from an exhibition in Belgium and was humiliated to be overtaken by a goods train. Very low rice pudding coefficient, that!
I think I'm right in saying that that was when he decided that the perceived wisdom of the time of very low-powered light aircraft was never going to work.
That led to the idea of adapting parts of the plentiful Airdisco V8s into the Cirrus to power the Moth.
That seemed to work...
The motorcycle engine idea, in theory, would probably work better now as 750cc 'bike engines now as opposed to then are very different. Probably lighter and certainly vastly more powerful. However, I'm sure a modern engine screaming at 10,000 plus rpm to develop its 100 plus bhp is entirely unsuitable for an aircraft, not to mention deafening.