Not being a pilot (yet) and having familiarity with various aircraft, and not having specs for the electrical systems for different aircraft available to me, I have a few questions... I know there are 14 and 28 volt systems out there. What existing aircraft use 14v and what aircraft use 28v? For a homebuilt (say a small twin, 200hp ea) what would be the best choice for a power system, 14 or 28v? 14v is common to automotive applications. But 28v cuts down on wire sizes, and is common to most military equipment (ex. a military diesel chev blazer is 28v). When I look at instruments in the aircraft spruce catalog I usually see both options. Personally I would lean toward the 28v system, but I'd like to hear what others think.