Blumlein's Plane Crash

[peter scott]

Trevor, I wondered exactly the same thing and in fact I've got it all wrong. The adjuster didn't tighten as I suggested. According to the Rolls Royce strip report: "The tappet screw had screwed right back and the excessive tappet clearance so set up had fractured the inlet valve stem at the reduced collet section. The remaining safety circlip prevented the valve from falling right into the cylinder. Following this, the valve would be allowed to drop so far into the cylinder and the hot gases would impinge on the flame trap element causing the latter to burn, finally igniting the incoming charge in the induction manifold."

I just happen to have a valve from a Griffon that may be slightly but not dramatically bigger just to show you the size of the "reduced collet section".

   

Peter