Mac
Couldn't find anything in your reference to show that the Argus As-104 was a detonation engine, why do you say that it was?
Many pictures of a V1 in powered flight show a trail of flame, this in itself would point to it not being a detonation engine.
Most research shows that only one practical, but experimental, PDE has been flown and that was in 2008. Research still continues into the technology due to the potential increases in fuel efficiency.