Very interesting to hear that there has been an attempt to migrate the Sabaru technology into light aircraft. I must admit this was the first thought that came to mind when I first heard about it.
At the first London Fly show I saw the Wilksch AIrmotive Jet A1 engine and heard Wilksch talk about the design and testing. As I recall the design team had even tried it out with red diesel since it might be have agricultural applications but were concerned about filter blockages from biological contaminants. To me the engine appeared to be ready for or very close to serial production.
My impression is that there are now proven technical designs for true aero engines – not just converted car blocks with their associated problems of gearbox, wear life, size, shape and weight - but they are not being taken forward into serial production by the major or even small specialist manufactures.
Is the absence of a good Jet A1 piston engine a market research problem rather than a technology barrier? The commercial case is not at the moment part of the public debate. I don’t see easy answers to even very basic question such as how many units a manufacture could expect to sell each year and what a reasonable retail price might be.
For the average owner if a replacement Jet A1 engine came in at the same price as an overhaul of an existing Continental or Lycoming petrol unit then I believe – assuming moving to Jet A1 did not raise ongoing maintenance or other costs of ownership – most people in Europe would swap out to a diesel unit.
Given the social benefits of moving from an engine fuel that contains lead there may an argument here to claim back some of the tax paid by the GA community to assist in the transition in infrastructure areas such as engineer training and conversion of LL100 pumps and storage over to Jet A1.
In the absence of a realistic understanding of the economics of a GA transition to Jet A1 as its primary fuel it is difficult to see how a manufacturing company could justify setting up a production line.