Wow! That's a lot of metal plumbing in front of the firewall. That stuff loves to absorb and transfer heat. Putting the pumps in front of the firewall where they are exposed to heat is inviting vapor lock at the pumps, which can cause engine stoppage with no recovery until it cools down. I went through this scenario helping a builder with a Sonex that seemed to be always on the edge of vapor lock. The solution was to fabricate a box around all those metal components, open on the bottom for the cooling air to exit, then add a NACA scoop to the side of the lower cowl to supply cooling air to the box.
We put a thermocouple on the gascolator before and after this mod. Before adding the cooling box to the fuel components in front of the firewall, the gascolator was measured at 180?F during flight. That is warm enough to boil the fuel and cause a vapor lock. After adding the cooling box to the fuel components, the gascolator always measured within 10? of ambient air temp. I am assuming you were already planning to cool these components, so am pointing this out as a potential safety issue for others that may want to put all those components on the front side of the firewall. I had friend that destroyed his E-AB aircraft when it vapor locked. When he was taxiing for take off with the engine hot following a previous flight, the fuel pressure dropped and the engine was running rough, so he flipped on the boost pump to restore pressure. The fuel pressure came back up to normal and the engine smoothed out, so he figured it was a vapor lock issue and would clear up once the engine got good airflow in the air. The problem is that his boost pump was also mounted in front of the firewall without any heat shielding or cooling air supplied. He made it to around 400' altitude before the heat saturated boost pump started cavitating as it also vapor locked. The engine quit forcing a landing on a road. He hit the power lines over the road first and had a less than stellar landing causing significant damage to his aircraft. It's worth noting that Piper put the boost pump and gascolator in front of the firewall on the PA-38 and the later PA-28 aircraft. In both cases, those components are mounted with a shield between the fuel components and the rest of the engine compartment and a small NACA scoop supplying air to the fuel components. -Jeff Scott Los Alamos, NM ? Sent:?Saturday, April 30, 2016 at 8:55 AM From:?"Paul Visk via KRnet" <krnet at list.krnet.org> To:?"KR EMAIL BOARD" <krnet at list.krnet.org> Cc:?"Paul Visk" <ppaulvsk at aol.com> Subject:?Re: KR> Facet fuel pump flare? Paul ViskBelleville Il?618 406 4705? Sent from my Sprint Samsung Galaxy S? 6. Pete, ?Here's a picture of my firewall with my primary and backup Facet pumps all with AN ?fittings. ?Along with my gascator, fuel pressure and fuel flow transmitters.?The idea came from the Sonex's Corvair engine installation manual. ?With this installation there is no pressure ice fuel in the cotpit. ? Paul Visk?Belleville Il?618 406 4705?.............................? The Facet is part 40108 and is made 3/8" flared and also AN-6. The Earl's fuel filters are part number 230106 and are AN-6. The Facet AN-6 is made for the racing world. Here is a link where you can get the AN-6 Facets: https://www.pegasusautoracing.com/productdetails.asp?RecID=84 Mark Jones (N886MJ) Stevens Point, WI
