---------------------------------------------------------- Kitfox-List Digest Archive --- Total Messages Posted Sat 10/18/08: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:57 AM - Re: Re: Header Tank Venting (Michael Logan) 2. 06:31 AM - Re: Re: Header Tank Venting (Noel Loveys) 3. 06:31 AM - Re: Re: Header Tank Venting (Noel Loveys) 4. 04:47 PM - Re: Header Tank Venting (JetPilot) 5. 05:00 PM - Re: Note on Ethanol (JetPilot) 6. 07:08 PM - Re: Re: Note on Ethanol (Guy Buchanan) 7. 09:54 PM - Re: Re: Note on Ethanol (Paul A. Franz, P.E.) ________________________________ Message 1 _____________________________________ Time: 05:57:36 AM PST US From: "Michael Logan" Subject: RE: Kitfox-List: Re: Header Tank Venting Also, don't fly with your flaps down for very long. Even at half full tanks, you will run out of fuel and the engine will quit. Don't ask me how I know. Mike Logan Series 5 -----Original Message----- From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of Lynn Matteson Sent: Friday, October 17, 2008 6:54 PM Subject: Re: Kitfox-List: Re: Header Tank Venting Noel- I also have a clear vent line running up to my right tank, which is equal in size to the left tank. However, I can see my vent line even with the header tank behind the right side of the seat. My fuel line and the vent line run parallel to the diagonal braces behind the seat, and all I need to do is glance over my right shoulder occasionally to check for fuel in both the clear glass Purolator filter, and the clear vent line. I only *need* to do this when I know that the fuel tanks are getting low, but I check it every so often just out of habit. Pucker time comes when I allow myself to get low on fuel and have to make a descent. Under these conditions...and I've done this maybe 4-5 times (bad, Lynn, BAD)...like Guy suggested, just leveling off for a moment will let some fuel fill the header, shut off the light, and the pucker relaxes. Lynn Matteson Kitfox IV Speedster Jabiru 2200, 572hrs Sensenich 62x46 flying again after rebuild, and new Electroair direct-fire ignition system On Oct 17, 2008, at 6:21 PM, Noel Loveys wrote: > > Lynn: > > What you did was one of the things my flight instructor made me > practice as > part of a forced approach. Even the certified spam cans have > issues with > fuel delivery form the wing tanks on occasion. > > My plane only has a vent to the right wing tank.. The left tank is > only > half the size of the right and yes I do have unequal fuel flow. I > also have > a clear section in the vent line so I can see when fuel in the > header starts > to run out long before it does. When I install the 912 I was > thinking about > relocating the header behind the seat. In that location I will no > longer be > able to see the vent line. > > Noel > > -----Original Message----- > From: owner-kitfox-list-server@matronics.com > [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of Lynn > Matteson > Sent: Friday, October 17, 2008 3:26 PM > To: kitfox-list@matronics.com > Subject: Re: Kitfox-List: Re: Header Tank Venting > > > I had uneven flow on ONE day....I was within 8 minutes of the > airport, and the low-fuel light came on, indicating 15 minutes of > fuel left. I noticed there was plenty of fuel in the left tank, so I > banked a bit to the right, sending that fuel into my header tank, and > I watched as the vent line filled up, the low-fuel light went off, > and I flew without incident into the airport to get 22 gallons into > my 26 (27 with header ) gallon (total) tanks. I may regret saying > this, but each pilot should know how his/her fuel system works, and > what can be done in a pinch to remedy a problem...either that or get > fuel more often. > > Lynn Matteson > Kitfox IV Speedster > Jabiru 2200, 572hrs > Sensenich 62x46 > flying again after rebuild, and new Electroair direct-fire ignition > system > > > On Oct 17, 2008, at 1:03 PM, n85ae wrote: > >> >> Header vents to both tanks, is usefull for equalizing pressure in >> the fuel >> tanks. This is the culprit for the uneven fuel flow problems in >> kitfoxes. >> All it take is a slight pressure differential, and you'll see a lot >> more fuel >> flow from one tank than the other. >> >> Jeff. >> >> >> >> >> Read this topic online here: >> >> http://forums.matronics.com/viewtopic.php?p 9194#209194 >> >> >> >> >> >> >> >> >> >> > > ________________________________ Message 2 _____________________________________ Time: 06:31:33 AM PST US From: "Noel Loveys" Subject: RE: Kitfox-List: Re: Header Tank Venting To keep it short... Follow the plans and vent the header tank! Forget about valves and breathers. Venting to both tanks sounds interesting but will accomplish nothing except an increase in weight and complexity. Noel Loveys AME Intern, RPP Kitfox III-A Ivo IFA, Aerocet 1100 floats -----Original Message----- From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of paul wilson Sent: Friday, October 17, 2008 9:49 PM Subject: Re: Kitfox-List: Re: Header Tank Venting Steve. NO -NO -NO You do not understand. You are getting advice from someone who has no understanding of the physics of fluid flow. You must vent the header. Valves in the header tank vents are just plain crazy.. Follow the instructions in the build manual. The factory guys are real engineers and have thought thru many things you may not even consider. And if you don't have the latest fuel system version go get it. And if you have a flying system that is not the latest system change it. As several have pointed out this in not the place to come up with something that will kill you. Remember screwed up fuel systems cause the most downed Kitfoxes of any other kind of failure. Probably because the builder did not understand the factory setup and changed it to his own design. Or just did not follow the instructions. Please Read Andys message below and try to understand it Paul ====== Just as a word clarification, so that terms aren't used incorrectly. The fuel system in a Kitfox is "gravity feed" and fuel pressure to the carb or engine fuel pump is "head pressure" from a gravity fed fuel tank. Strictly gravity only. There is no "siphon action". Designers have to determine that the fuel tank is high enough in normal flying/attitudes (nose high/nose low) and fuel line size adequate to provide a certain fuel pressure or head pressure for the fuel consumption of the engine used. If your engine installation requires additional pressure to the engine pump than head pressure can provide, an electric pump must be installed prior to the engine pump or carb (ala low wing aircraft). Fuel line size and head pressure to the engine is all that insures that an adequate supply of fuel is maintained to the metering device, unless you have a fuel pump located at each tank outlet to supply increased fuel flow. Most small aircraft under 140 hp, 3/8" line is used, that will that will supply more enough fuel for engine consumption. As engines get larger, fuel line size goes up, 1/2", 5/8", etc. The only time fuel is "sucked" or "siphoned" from a tank is if you have a pump located at the tank. It is extremely important that the fuel lines and the vent lines be angled down to the header tank or on a constant slope, problem areas are at the wing pivot and the horizontal routing to the header tank. Especially in the vent line. Air and fuel must have an unimpeded path and a way to get out and into the upper wing tank, if both lines to one tank have a low or high spot you could run into a fuel lock situation on that side. Installed correctly and under normal flying and fuel conditions, the vent line has fuel in it and should correspond to the level of fuel in the tank. In a long, steep, nose down descent with low fuel, your fuel pickup will be higher than the fuel level in the tank, as the fuel runs to forward to the front of the tank. The tank is still vented, fuel to the header tank is supplied only by the remaining fuel in the fuel line from the pickup to the header tank. Leveling off routinely will then raise the fuel level above the fuel pickup/screen and will flow back down into the header tank. The air being displace by the fuel will go up the vent line and into the fuel tank. If the vent were blocked then air would have to travel upstream against the fuel going down into the header tank. If it is on a constant slope this should not cause a problem other than fuel will not fill the header tank as fast as it has to make room for air in the line going up. This is why the vent line is important. If you look at aerobatic biplanes with a center section upper wing mounted fuel tank, you will see a forward fuel pickup. This is for nose down attitudes. Most Cessna's have a forward pick up location, we can't because of the folding wing design. The fuel line would have to run down the forward doorpost frame. (Which it does in a Cessna) There is nothing wrong with a single vent line to one tank or a vent line to each tank. Because we have a folding wing design we cannot have a interconnecting vent line (wing tank-to-wing tank) like a Cessna that they use to help even the fuel burn from each wing. In a perfect world (no slip nor skid, wings level, no turbulence, etc) Kitfox dual vent lines are used to keep fuel burn equal. The fuel vents on the "filler caps" provide a very slight positive pressure in the tanks, but mainly to fill the void of used fuel. Make sure the caps are on correct and the gaskets are sealing. One of the reasons for the long periscope vent line on the cap is to get the vent into static atmospheric air. The low pressure on top of the wing where the fuel cap is can cause siphoning of fuel, which is why a gasket check is a good idea. The reason that the vent line from the header tank needs to be a constant slope to the tank vent boss is to ensure that you don't create a "trap" for air. A dual vent line system helps to ensure positive flow to the engine just incase one vent line were to become blocked. Depending on your engine installation it is possible run the fuel low enough that there is not enough head pressure to supply the carb, even though there may be fuel in the header tank. I suggest a standby electric fuel pump (Faucet 4-6 gph) be mounted below the header tank outlet that can be turn on during takeoff/landing and low fuel situations. I installed one in my fuel system. To insure positive pressure. I would: I would check the fuel caps first to make sure they are not blocked, pointing forward and the gasket seals. Ensure that the fuel and vent lines to each tank are on a constant slope to the tank. Verify that the fuel level in the vent line corresponds to the level of fuel in the tank. Andy ============ At 06:29 AM 10/17/2008, you wrote: > >Obviously there are differing thoughts on this issue. What I am >getting so far is that it MAY not be necessary to close the venting, >but closing the venting will not harm anything and MAY actually HELP >in some instances. Would that be a accurate summary? > >-------- >Steve Wilson >Huntsville, UT >Kitfox Model 1- 85DD >912A / 3 Blade Warp Drive >Convertible Nosewheel & Tailwheel > > >Read this topic online here: > >http://forums.matronics.com/viewtopic.php?p 9161#209161 > > ________________________________ Message 3 _____________________________________ Time: 06:31:56 AM PST US From: "Noel Loveys" Subject: RE: Kitfox-List: Re: Header Tank Venting IMHO most fuel starvation will come from blocked cap breathers on the left tank. Sigtaturea Noel Loveys Campbellton, NL, Canada CDN AME intern, PP-Rec C-FINB, Kitfox III-A Ivo IFA, Aerocet 1100 floats noelloveys@yahoo.ca From: owner-kitfox-list-server@matronics.com [mailto:owner-kitfox-list-server@matronics.com] On Behalf Of paul wilson Sent: Friday, October 17, 2008 9:55 PM Subject: Re: Kitfox-List: Re: Header Tank Venting Lots of examples Just do your homework Agree. Asymmetrical fuel flow from the tanks has nothing to do with starvation. Fixes for it are not necessary. Just follow the details on the install and the issue will go away. Nice fat lines are also good and no restrictions in any of the lines are also good. No filter or other components in the header to tank lines helps that situation. Paul At 09:26 AM 10/17/2008, you wrote: If as you suggest the header tank vent was OFF then in Lowell's example or other similar scenario the automatic refilling of the header tank would be prevented and air/fuel blockages of the two feed lines from the wing tanks WOULD likely slow or prevent flow to the header tank and encourage fuel starvation with adequate fuel remaining in the wings. Add my name to the many with asymetrical fuel flow from the tanks but no evidence of the header tank being deprived. I don't have a low fuel warning but there are many out there to monitor the possiblity of starvation. Were there any warnings that were triggered as a result of the asymetrical draw. What are the specifics of the "many crashes due to fuel starvation"? Sounds like urban myth to me. John Kerr Classic IV, 912ul, 780 hours. Logan UT ====== UOTE>< /body> Kitfox-List Email Forum - http://www.matronics.com/Navigator?Kitfox-List - MATRONICS WEB FORUMS - http://forums.matronics.com - List Contribution Web Site - -Matt Dralle, List Admin. http://www.matronics.com/contribution ________________________________ Message 4 _____________________________________ Time: 04:47:49 PM PST US Subject: Kitfox-List: Re: Header Tank Venting From: "JetPilot" Andy Is Correct, Putting valves and closing the vent on the header tank is just plain dangerous and dumb. Someone is giving out very bad and dangerous advice. There are things that this " Bad Advice " person did not take into consideration. It would take a lot of research and evidence before I would even think about changing the Kitfox design. EAA has people very well versed in fuel systems, I would at least talk to some real experts before I changed a good and proven design. Mike -------- "NO FEAR" - If you have no fear you did not go as fast as you could have !!! Kolb MK-III Xtra, 912-S Read this topic online here: http://forums.matronics.com/viewtopic.php?p 9308#209308 ________________________________ Message 5 _____________________________________ Time: 05:00:44 PM PST US Subject: Kitfox-List: Re: Note on Ethanol From: "JetPilot" Making and Burning Ethanol as fuel is the greatest Environmental distster this planet has ever faced. Noel is correct, producing ethanol takes more energy and creates more CO 2 than just burning the gasoline, but it get much worse [Shocked] Being that we are now burning Food for fuel, to make up for the food shortage, Forests in Brazil, Malaysia and all over the world are being slashed at a much greater rate than ever before. The ethanol demand is driving this. It takes enough corn to produce 20 gallons of ethanol to feed a person for a year, did we forget all about morality and the starving people on this planet ? Why would we do such a stupid thing, CORRUPTION. Special interests, farmers votes, there is enough money behind this to make it happen, even though it is harming the planet immensely. We have the best government money can buy. I forgot to mention the most important aspect of ethanol, it causes problems when used in our airplanes [Evil or Very Mad] Mike [Evil or Very Mad] -------- "NO FEAR" - If you have no fear you did not go as fast as you could have !!! Kolb MK-III Xtra, 912-S Read this topic online here: http://forums.matronics.com/viewtopic.php?p 9309#209309 ________________________________ Message 6 _____________________________________ Time: 07:08:41 PM PST US From: Guy Buchanan Subject: Re: Kitfox-List: Re: Note on Ethanol At 05:00 PM 10/18/2008, you wrote: >I forgot to mention the most important aspect of ethanol, it causes >problems when used in our airplanes [Evil or Very Mad] Thanks, Mike, for making this post at least tangentially aviation related. However this thread was beat to death quite recently, so I am going to ask you and others to take it off list. Thanks, Guy Buchanan, Kitfox List Moderator San Diego, CA K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar. ________________________________ Message 7 _____________________________________ Time: 09:54:02 PM PST US Subject: Re: Kitfox-List: Re: Note on Ethanol From: "Paul A. Franz, P.E." On Sat, October 18, 2008 5:00 pm, JetPilot wrote: > > Making and Burning Ethanol as fuel is the greatest Environmental distster this planet > has ever faced. Noel is correct, producing ethanol takes more energy and creates > more CO 2 than just burning the gasoline, but it get much worse [Shocked] clip clip This an interesting topic however, this is not the proper forum for it. It's a good idea to discuss closely related subject matter to the building and operating of a Kitfox and powering one. If the topic drifts too far off, the maillist will lose it's usefulness and some participants will lose interest. I don't think there needs to be silly restrictions on what you can discuss and quoting URLs for products we find seems fine to me too. Just for drill there is a nice section at the bottom of this page on Kitfox-List Usage Guidelines: It's actually pretty good practice, IMHO, to follow these guidelines. -- Paul A. Franz, P.E. 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