----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]---- At 04:48 PM 10/3/02 -0800, Pete Thomson wrote:
Evening all, I had an experience which I thought I would ask for some input on. The glass tube on the nose tank gauge started coming out of the aluminum gas cap about 30 minutes after take off. That's happened to me! Very distracting, because you think of it as a vertical point of reference over the curving cowl, and when it tips to one side, you have to work at NOT looking at it (which is hard to do when landing :-) ). It came out very slowly but was at about 1/4 inch out when I noticed. It did not appear to move any more but I thought about the syphoning issue and headed back for home, it was loose and came out easily on the ground. I fixed it and then continued my 4 hour flight. The question I have is this :- in your opinion is the hole through which the wire goes big enough to allow the propwash to syphon all the gas out of the header tank faster than the gas would normally get returned to the wing tanks? I am sure at least one of you has hit a bird or something and had this experience, my concerns were twofold, one running out of gas and two the fire hazzard from the gas getting on the alternator in the engine compt. Your thoughts and experiences with this would be appreciated. The nose tank gas cap on my Coupe is vented towards the front. I think you were right to land and fix it. But no, it isn't going to siphon all the gas out. Think about it...the gas doesn't touch the cap except when the tank is really full or you're pitched up and the tank is pretty full. That said, any time something is out of the ordinary, you may as well land and fix it rather than have some un-foreseen consequence of something seemingly innocuous turn a problem into an emergency. But, look at the relationship of the cap to the firewall... the firewall is several inches forward of the cap, which is really about vertically aligned with your knees. Gas that spurts from there tends to just get channeled down the windshield rubber and doesn't make it far before the slipstream turns it into vapor. Also, the cowling (together with the big hunkin' grommet around the filler neck) pretty much assures that unless gas can crawl against the blast of wind coming from the cowling, it's not going to find the alternator. If you wanted to stop the siphoning or spurting in short order, you could have shut off the flow of fuel to the header tank either via the valve or (on an O-200 conversion) the fuel-pump switch. Then you'd still have the better part of an hour to land, assuming you didn't turn it back on to add some more fuel to the header. If I fill both wing tanks pretty high with the header tank full, the overflow seems to back up, leading to some squirting during taxiing. When that happens, I just kill the electric fuel pump until the header is down a pint or so from the tippy-top, and after that all is happy again. If I remember, I tend to turn off said pump during the taxi from the last landing to the gas pumps, and that makes some 'room' in the system so I don't make a mess. The electric pump, unlike the mechanical one, doesn't get any less efficient at taxi RPMs, so the fine balance in the system gets a bit upset if things are really full. Greg ================================================================== TO UNSUBSCRIBE go to: http://ercoupers.com/lists.htm
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