I came across an interesting product called Blazecut that would be a lightweight solution to fight an engine compartment fire. Check out the detailed spec sheet and the video demonstration on the site. No weight is given, but it holds 0.5 kg of suppressant so I'd guess a 1-2 kg total weight.

It seems to me that the most likely scenario for fire in a homebuilt is not an in-flight fire, but a post-crash fire because fuel from a ruptured tank or lines contacts hot exhaust, electrical sparks, or sparks from metal scraping the pavement. In that case, especially in aircraft that have the fuel tank in the fuselage near the crew for CG reasons, something like one of these manual/automatic systems would provide awfully cheap peace of mind. Installed weight is about 4-5 kg.

What do you think? I don't think it's a money question -- if you can afford to build and fly a plane, you can afford to spend a few hundred bucks more to prevent a fire -- but are you willing to add 2-7 kg to the empty weight of your aircraft for fire safety?

Cheers,

Matthew