I've been thinking about putting an "AFFF" system in my 8. I need to do more research but it's an aqueous foaming film that seems to be really tenacious in extinguishing flames and keeping them extinguished. It's being used in Auto Racing and seems to be pretty neat. They use a bottle with two nozzles, one for the engine compartment and one for the cockpit. I'm not sure how it would do on an engine fire in the air, but I'm sure it would be better than halon.
It's pricey compared to chemical powder and halon, but the thought of an airborne fire scares the h--- out of me.
Here's the link to an Auto Supply source.
http://www.continentalmotorsports.co...firesystem.htm
Mannan Thomason
RV-8 Slo build--wiring-engine rebuild