Brian Abraham
Off subject topic: the proposed Gemini engine has
NOT flown in any aircraft nor airships as you state. When announced earlier this year it was only a model with nothing inside! Nice though it looks!
It is the DAIR engine which has been flying both in airships and aircraft. Refer
here That English company has invested over £1M in their diesel project so far. They own the IPR, having paid for the development and production costs of the engines over the years.