I fill my main tainks before each flight.I also do the math of how long I will fly and when I need to come down and fuel. As far as I am concerened the header tank is my reserve tank and the float moving is the same as a red warning light.These things are hard to park at altitude .I have run out of gas in my mower,motorcycle,truck , car , boat over the last 50 years. I dam sure dont intend to run out in my aircraft. --- On Thu, 8/6/09, William R. Bayne <[email protected]> wrote:
From: William R. Bayne <[email protected]> Subject: Re: [ercoupe-tech] Re: how full of fuel To: "Techlist Ercoupe" <[email protected]> Date: Thursday, August 6, 2009, 9:16 PM All, Gary asked "I wonder why the coupe tends to lose fuel this way". (siphoning) There are a variety of fuel systems "out there", and therefore more than a few reasons for such fuel loss. Prewar 65HP coupes had a five gallon fuselage tank and one 9-gallon wing tank. It was on the right side, opposite the pilot's weight. Both were of ternplate. Excess fuel transferred by the fuel pump returned from the fuselage tank via an overflow line to the wing tank until all wing tank fuel was consumed. Postwar 75HP 415-Cs added another 9-gallon ternplate wing tank. A crossover line connected the two wing tanks and the fuel transfer pump drew from a tee in the crossover line nearer to the right tank. The main tanks fuel gauge was in the right tank. The present Ercoupe Parts Manual ignores the fact that Ercoupes through Serial No. 812 required wing tanks, part number 48028L & R, allowing steel main gear legs to attach to the front of the main wing spar. Ercoupes from Serial No. 813 to 2622 could be altered to take the later aluminum wing tanks per Ercoupe Service Memorandum No. 31, item #5, and ESM 39. The Service Manual says 5 gal. fuselage tanks of stainless steel were installed commencing with Serial No. 2469. At some point replacement wing tanks were fabricated of stainless steel, but identical to and interchangeable with tern ones. Aluminum tanks were installed commenting with Serial No. 2623 and the overflow line from the new 6-gallon fuselage tank now went to the left wing tank, per ESM 31, Item 17. This information conflicts with ESM No. 42, Fig. 1, which shows the overflow going to a tee in the line connecting the main tanks near the left one for Serial Nos. 2623 through 3220. The fuel system schematic for Ercoupes "3468 & Subsequent" in ESM No. 43 and in the Ercoupe parts Manual do NOT agree. Ercoupes with fuselage tank overflow going to a single wing tank require VENTED caps. I believe the one in ESM No. 43 to be correct, and the one on p. 28 of the Parts Manual, Fig. 20, to be incorrectly identified, and actually applicable to Serial Nos. 4424 & up (and those 100+ 415-Cs that ERCO modified in the field to become 415-CDs). This is the fuel system shown in Flight Manual for the 415-D (and subsequent CD, E and G Models) with the fuselage tank overflow splitting into separate overflow lines to each wing tank. Any Ercoupe (Forney, Alon, M10) with this system was originally intended to have UNVENTED wing tank caps. If an Ercoupe (et al) with UNVENTED wing caps is venting wing tank fuel in flight the cap/gasket/flange is not sealing correctly. If one with VENTED caps is venting wing tank fuel, I would suspect (1) the cap/gasket/flange is not sealing correctly, (2) the 1/16" hole in the fuel transfer pump discharge fitting is too big (or not so restricted), (3) one of the wing tank cap vents is obstructed (or somehow different in size from the other or (4) the cap has been put on backward (Serial Nos. 2623 and earlier only). Serials prior to 3468 had a smaller single overflow line, and there could be some initial conditions of flow with full wing tanks that returning fuel to one main tank is unable to "balance" via the crossover line between the main tanks (perhaps a partial obstruction or dirty finger strainer). There are relatively FEW Ercoupes that experience other than momentary "siphoning" if the above suggestions are diligently applied. It was always my personal practice to fill the fuselage tank first, then the wing tank that did NOT receive overflow, and finally the one that did...each within 1/2" or so of the cap seat. Regards, William R. Bayne .____|-(o)-|____. (Copyright 2009) -- On Aug 6, 2009, at 13:58, Hartmut Beil wrote: > > > Maybe the line itself is the restrictor. > In any event, the tanks slowly level out when being filled. > > Like I said, what do I know. > > > Hartmut > > To: [email protected] > From: [email protected] > Date: Thu, 6 Aug 2009 12:26:32 +0000 > Subject: [ercoupe-tech] Re: how full of fuel > > Thats the first I have heard of a restrictor in the line between the tanks???? > > Kevin1 > > --- In [email protected], Hartmut Beil <hb...@...> wrote: > > > > "I wonder why the coupe tends to lose fuel this way" > > > > The Ercoupe fuel system takes the fuel from the interconnected two main > > tanks, pumps it in the nose- or header tank and from there all fuel in > > excess of the engine need flows over to the left wing tank (in most cases). > > > > The left wing tank is connected to the right one and here the fuel starts > > its journey again. > > > > The problem is that the pump takes fuel from both interconnected tanks but > > the overflow goes into one of the main tanks only. > > > > The fuel does not even out between both main tanks, due to a restrictor > > fitting in the connecting line. > > > > So if you don't leave a small buffer for the fuel , it has to overflow. > > > > Later style fuel systems tried to correct the overflow issue by proving an > > header tank overflow into both main tanks, I have such system in my plane. > > > > It works , but only on level ground or in-flight. When my coupe is slightly > > tilted, the fuel again flows only into one wing tank and the fuel sprays > > out of that tank. > > > > The fuel system in a cessna does not have these problems, since their tanks > > are all above the engine, all are gravity feeding the engine and the whole > > business of pumping fuel through a system might not be an issue there. > > > > But what do I know. > > > > Hartmut > > > > > > > > To: [email protected] > > From: alfen...@... > > Date: Wed, 5 Aug 2009 19:28:56 -0700 > > Subject: [ercoupe-tech] how full of fuel > > > > I have the 46 coupe 415-C. I also have the 7.5 gal tanks, instead of 9 like > > most of you do. My question is, how full to fill the tanks. I have heard > > that up to the brim, and I will lose fuel to siphoning. I never had this > > problem in my 172, and I wonder why the coupe tends to lose fuel this way. > > I am now putting too little fuel in, and just want to know a good ballpark > > average the rest of you men/women use. Thanks for reading this. > > Gary
