701 Fuel System - Zenith Aircraft Builders and Flyers2024-03-29T09:13:07Zhttps://zenith.aero/forum/topics/701-fuel-system?feed=yes&xn_auth=noBrilliant sample. It will ce…tag:zenith.aero,2017-10-14:2606393:Comment:5920692017-10-14T00:02:17.561ZEric Staceyhttps://zenith.aero/profile/EricStacey
<p>Brilliant sample. It will certainly be very useful.</p>
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<p>Thanks again,</p>
<p>Eric</p>
<p>Brilliant sample. It will certainly be very useful.</p>
<p></p>
<p>Thanks again,</p>
<p>Eric</p> Eric,
I meant to post this wh…tag:zenith.aero,2017-10-13:2606393:Comment:5920652017-10-13T23:54:06.258ZCurt Thompsonhttps://zenith.aero/profile/CurtThompson75
<p>Eric,</p>
<p>I meant to post this when you asked this question but forgot. Sorry about the delay. A drawing of my fuel system is in my POH. I'll try to attach it here.</p>
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<p>p.s. I never really got the fuel flow sensors to work very well. They are accurate to about +/- 10%. I've kind of given up after trying everything I could think of.</p>
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<p>Curt</p>
<p>Eric,</p>
<p>I meant to post this when you asked this question but forgot. Sorry about the delay. A drawing of my fuel system is in my POH. I'll try to attach it here.</p>
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<p>p.s. I never really got the fuel flow sensors to work very well. They are accurate to about +/- 10%. I've kind of given up after trying everything I could think of.</p>
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<p>Curt</p> Hi Eric
I think you will deci…tag:zenith.aero,2017-02-11:2606393:Comment:5514112017-02-11T00:49:46.467ZJoe Spencerhttps://zenith.aero/profile/JoeSpencer
<p>Hi Eric</p>
<p>I think you will decide that the header tank will do the same as the "gascolotor" shown in my plans set.( Where the 2 lines from the tanks meet and join into one line). I believe the principle will be the same. And depending on how the rest of the system is setup, a header tank can bring on a whole other set of problems.</p>
<p>If you're gonna go with OFF BOTH the only way I know to ensure even flow is with a balance line between the tanks. Others may know different. Rigging…</p>
<p>Hi Eric</p>
<p>I think you will decide that the header tank will do the same as the "gascolotor" shown in my plans set.( Where the 2 lines from the tanks meet and join into one line). I believe the principle will be the same. And depending on how the rest of the system is setup, a header tank can bring on a whole other set of problems.</p>
<p>If you're gonna go with OFF BOTH the only way I know to ensure even flow is with a balance line between the tanks. Others may know different. Rigging problems can cause uneven feed too. There are hundreds of 701s out there that are running the plans setup(I assume). I've heard quite a few reports of problems with that but I guess they mange to motor around ok. But my experience wasn't sat for me. good luck JS</p> Anyone put a header tank in t…tag:zenith.aero,2017-02-10:2606393:Comment:5512322017-02-10T23:09:09.247ZEric Staceyhttps://zenith.aero/profile/EricStacey
<p>Anyone put a header tank in the rear cockpit "luggage" space collecting from both wing tanks and running a single line from the header tank? Would this overcome the uneven feed Joe refers to?</p>
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<p>Thanks all...</p>
<p>Eric</p>
<p>Anyone put a header tank in the rear cockpit "luggage" space collecting from both wing tanks and running a single line from the header tank? Would this overcome the uneven feed Joe refers to?</p>
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<p>Thanks all...</p>
<p>Eric</p> The OFF BOTH valve was a prob…tag:zenith.aero,2017-02-08:2606393:Comment:5508062017-02-08T14:27:01.810ZJoe Spencerhttps://zenith.aero/profile/JoeSpencer
<p>The OFF BOTH valve was a problem on mine. With the 2 tanks feeding at the same time thru the same valve there was the well known uneven feed. And since mine wouldn't reliably gravity feed thru the small, long line I had to depend on the fuel pump(s). So, if one of the tanks uneven fed down to empty my assumption had to be that the pump would suck air outa the empty tank. Before the mod to L R OFF I've landed well short of destination cause one of the tanks was nearing empty...I still had…</p>
<p>The OFF BOTH valve was a problem on mine. With the 2 tanks feeding at the same time thru the same valve there was the well known uneven feed. And since mine wouldn't reliably gravity feed thru the small, long line I had to depend on the fuel pump(s). So, if one of the tanks uneven fed down to empty my assumption had to be that the pump would suck air outa the empty tank. Before the mod to L R OFF I've landed well short of destination cause one of the tanks was nearing empty...I still had fuel in the other tank but had to consider it trapped fuel, thus the mod to what I did and no problems at all now. Wouldn't have it any other way ....total control over the fuel. I consider that a basic requirement to any fuel system. Course the PIC has to manage the tank selection bu I've never considered that a factor. But you may; your call as usual. IIRC some of the high wing Cessnas have the OFF BOTH system and no uneven feed problems that I'm aware of...I assume there is a balance line between the tanks to equalize the pressure and feed. Maybe somebody here knows for sure about that.</p>
<p>If I was planning to use the plans system, like Bob Jones, I would at least go to 3/8 AL line with AN fittings; that would probably reliably gravity feed. Mine had a bare trickle at the carb with the line detached and less than that with the tail on the ground and low fuel in the tank.</p>
<p>That's my experience with that YMMV as always do what YOU want</p>
<p>Best</p>
<p>Spencer</p>
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<p></p> So they do, Bruce. Thanks fo…tag:zenith.aero,2017-02-07:2606393:Comment:5506812017-02-07T01:04:29.434ZEric Staceyhttps://zenith.aero/profile/EricStacey
<p>So they do, Bruce. Thanks for pointing that out. Good to be on the same page now.</p>
<p>So they do, Bruce. Thanks for pointing that out. Good to be on the same page now.</p> the 701 plans i have show fu…tag:zenith.aero,2017-02-07:2606393:Comment:5507692017-02-07T00:37:43.463ZBruce V. Collinshttps://zenith.aero/profile/BruceVCollins
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<p>the 701 plans i have show fuel line schematics on sheets 7-WTO-1 & 2</p>
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<p>the 701 plans i have show fuel line schematics on sheets 7-WTO-1 & 2</p> I did mine like it sounds Bob…tag:zenith.aero,2017-02-06:2606393:Comment:5508622017-02-06T19:37:57.263ZJoe Spencerhttps://zenith.aero/profile/JoeSpencer
<p>I did mine like it sounds Bob did. I had trouble with the POS plans system; it wouldn't reliably gravity feed and I had the older Rotax fuel pump fail and it started quitting but had a b/u pump.mine comes outa the tanks to a facet pump on each side mounted above the pilot and pax head. then straight forward and down the w/s braces to a fuel valve on the dash then thru the firewall to a gascolator mounted on the f/w about a foot from the top and then forward to the pump and carbs. 3/8 AL…</p>
<p>I did mine like it sounds Bob did. I had trouble with the POS plans system; it wouldn't reliably gravity feed and I had the older Rotax fuel pump fail and it started quitting but had a b/u pump.mine comes outa the tanks to a facet pump on each side mounted above the pilot and pax head. then straight forward and down the w/s braces to a fuel valve on the dash then thru the firewall to a gascolator mounted on the f/w about a foot from the top and then forward to the pump and carbs. 3/8 AL tube/AN fittings except downstream of the gascolator and flex hose/fire sleeve forward from there.</p>
<p>I put the 2 pumps at the tank outlet cause on an aggressive light weight climb it's possible on my plane to get the rotax fuel pump very near or above the fuel tank level and if that pump quits it won't gravity feed and also the corner of the door post is a high spot that the fuel has to climb in a climb. I use the pump for the selected tank on takeoff. My valve is L R OFF so no transfer between tanks.</p> Thanks Bob. It seems that t…tag:zenith.aero,2017-02-06:2606393:Comment:5506632017-02-06T15:46:20.034ZEric Staceyhttps://zenith.aero/profile/EricStacey
<p>Thanks Bob. It seems that the alum fuel line may be much cleaner than hose, also req. less maintenance.</p>
<p>Thanks Bob. It seems that the alum fuel line may be much cleaner than hose, also req. less maintenance.</p> Thank you, Francois.
tag:zenith.aero,2017-02-06:2606393:Comment:5506182017-02-06T15:44:44.473ZEric Staceyhttps://zenith.aero/profile/EricStacey
<p>Thank you, Francois.</p>
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<p>Thank you, Francois.</p>
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