AD-06. Don Simpkins photos.
This was the next F1J engine to appear on the market after the Shuriken. It was an Italian engine made by Alberto dal Oglio. While the Shuriken in its four variants was the only engine made by Fred Baldwin and Jim van Arsdall, Alberto was already well known for his excellent 2.5 cc engines and this experience shows in AD-06's greater power output. The engine is no longer available, but was the standard to judge other engines by until the Cyclon 06 appeared.
The crank case was a sand casting. Like all AD engines, the alloy used was specially formulated by Alberto. The casting and all external components apart from the needle assembly had a plain white metal finish. The gold tint in the photos is a lighting effect.
I have never owned an AD-06, but samples typically ran at 29000 rpm on APC 6x2 and 25% nitromethane. It was a twin ball race engine using ABC cylinder technology and its own proprietary glow button, which was secured by a ring clamp that enclosed the button body and screwed into the head. The prop driver was collet mounted. The engine was supplied with the semi-streamlined prop nut seen in the photos.