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At 12:24 PM 11/27/00 -0800, ken townsend wrote: >Hi all, I was talking to a guy that was also a member of the coupe >"gliders" >club. He told me that a piece of the shellac coating on the fuselage tank >float >came off and plugged his fuel line. He said I should change to a different >type >of float but wasn't sure what. The newer floats come in two versions. One for avgas, and one for environments where there may be auto-fuel present. Actually, if the shellac was dissolved by the fuel, it's likely the fuel had alcohol in it, which is a no-no in any case, MoGas STC or not. It may well be that the slug of alky was in gas from twenty or a hundred fill-ups previous, too. Epoxy (not polyester) resin is one coating which should be all-fuel safe on a cork. If I were doing a MoGas STC on a 'Coupe with older fuel floats, I'd coat the corks in that stuff. It can be simple as mixing up a pot of common epoxy glue and coating everything thoroughly with an acid brush. I say the latter because they are cheap, and the brush ain't gonna be good for anything brushing-wise again. Skyport has float gauges that are certified auto-gas safe. Being of the rain-proof variety, they also keep water out of the tanks and give you something to mark relative fuel levels upon. >Would the primer be a possibility to use for fuel if this happened in >flight? The answer to this question can be divined simply by putting your head under the panel and looking at how the primer is plumbed. Assume the fuel outlet from the header was blocked: Would fuel to the primer be flowing? It's always good to get to know, first hand, the systems of the airplane you fly. So duck under there and tell us what you found. >And lastly, my fuselage fuel gauge moves to "low" when climbing but will >come >back to "normal" soon (but not immediately) after I go straight and level. How low does it go? Mine does that too, a little. But not quite as you describe, so read on. >The >way the tank is built and the location of the float make me think the >guage >should be reading "full" during climb. I wonder if my fuel pump is putting >out >enough fuel to keep the tank full at full throttle. Again it is not a >problem in >level flight, it only occurs in hard climbs. You have to consider the location of the overflow as well. Mine tends to come up low-ish when I level off from a climb. I believe that is because the flat 'pan' of a tank is overflowing more vigorously at any angle other than flat. Now, it's not real low, maybe a half-inch lower than its static on-the-ground position. Really, after any maneuvering at all, the float tends to be a little lower than after prolonged straight-and-level flight. For an illustration of why, take a flat cake pan and fill up with water to 1/4" of the brim. Note how very LITTLE you have to lift one end or one corner to spill some water out. Then think about the deck-angle during climbing flight. Try and see where your overflow is located and do some thought-experiments using your cake pan. Consider whether what you're seeing is during the climb or after the climb. Does it keep going down? If you're in a deficit situation, it's going to keep going down to the stop (and that 'stop is more ways than one'). >Any suggestions? Quick check for the fuel pump? Assuming you can do it without red-lining, why not open the throttle to climb power in level flight and fly that way for a while? Does the pump keep up? If so, then it's capable of pumping more fuel then the engine is capable of drinking. Now this is not a totally true test, because your RPM's will be higher and the pump will be going faster. But it's another data point. In my case, it's only a couple of hundred RPMs so it's pretty close. Perhaps the best test is whether the float goes to a certain point in a climb at a constant deck angle, and stays there, or if it shows signs of going all the way down to the end. If it were me conducting the test, I'd probably do it right over a good airport, just in case... All of this illustrates an important point about the Ercoupe fuel system: the header tank capacity as marked is the MAXIMUM capacity. I'd guess that mine is down a good gallon for a few minutes after a climb to 3000 feet, just due to the angle of the airplane. That means that, if the fuel pump went just then, I'd have a bit less time than promised to select a landing spot. By the way, I mark the nominal level of the header tank on my Rain-Proof gauge's glass via application of a red ponytail elastic. A rubber band will work, too. The level marked is the level after the engine has been ground-run for a few minutes, and with the plane parked level. I find that doing so has caused me to spend a lot less time wondering 'is that float going down? Nah, it isn't well maybe it is, nah, it's just because you're over 50 miles of unbroken forest, well maybe it really is, nah...' Now I just ask... 'is that engine rough?' or 'was that a mis-fire?' Hell if we didn't have anything to fret about, we'd just fall asleep. Greg --------------------------------- to unsubscribe send mailto:[EMAIL PROTECTED] ___________________________________________________________ T O P I C A http://www.topica.com/t/17 Newsletters, Tips and Discussions on Your Favorite Topics
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