Thank you all for your suggestions and clarifications.
This might become unsolvable.
Did it Fly?
I guess so
P19 Glimmering is the best suggestion so far!
I was thinking about the Cri-Cri Obesity.
I have send an email to the Sisteron soaring club if they can find it in their visitors logs.
Has anyone explored the search path of the engines?
I think it are no diesels but Hirth 3702.
Hirth