I was unable to get animated windshield wipers working in a virtual cockpit, using an FSX-updated version of that code of Bill's that's on the Frreflight design site. So instead, I'm trying to make a simpler version - just a 2-way toggle switch that can turn the wipers on and off. The animation would consist of the wipers rotating in one direction, then back to the starting position - and continue looping. Does XML provide a way to make an animation loop?

You don't have to do anything special in FSX for "looping animations." As long as the part is driven by "Ambient" (any of the six variations) or "Non-Random Ambient" the animation will loop forever...

Got it working. You da man, Bill!