Safety Officer Posted January 10, 2014 Report Share Posted January 10, 2014 Just an FYI, All three model CT's have the same fuel tank. the SW, LS and the LSi all have the same tank and they all have a baffle. The earlier FD models have small holes in the bottom of the baffle to allow fuel to move from outboard to inboard and the baffle helps with sloshing and from having a high rate fuel transfer from either inboard or outboard. The later LS models had a small hinged door placed over the baffle door.This was to help prevent fuel from transferring from the inboard to the outboard part of the wing. Link to comment Share on other sites More sharing options...
suntheman Posted March 16, 2015 Report Share Posted March 16, 2015 Very Dangerous landing with one empty gas tank & the other full, strong cross wind condition. I flew cross country with CTsw about 3.2hrs (head wind condition), we have total fuel 120Liters (65L in right tank & 55). My weight 55kg & other pilot 95kg on the right seat. While approaching airport destination, we have pretty strong cross wind condition from the right (about 10kts-40deg from the right side) . I knew before if airplane tendency going bank to the right because Fuel in left wing is empty and the other is FULL. Basic theory when training,when landing at crosswind "yoke/stick to the wind & opposite rudder". I keep stick to the right make airplane wing level, and left rudder to make align nose with runway. and you guys know what? after airplane becoming flare, right wing going fall, and I pushed left pedal rudder to keep airplane centerline until full wing no longer have enough a lift in low speed, right wing continue going down, worstly my weight only a half than right seat... airplane touch down with right wheel first and its very dangerous landing, maybe it will be crashed if we got more cross wind other day, I checked fuel flow.. with same fuel quantity left & right tank.. I drain, and I found left tank going empty (no really empty but its ok for unsable fuel onboard) after it fuel on right wing going down. Why fuel in left wing going empty first? any solution? regards Link to comment Share on other sites More sharing options...
Roger Lee Posted March 16, 2015 Report Share Posted March 16, 2015 This topic and discussion goes back to 2006 and is revisited every few years with new owners. This discussion usually goes at least 10 pages and comes down to someone blaming FD. Many CT owners have one tank that drains faster than the other. It is a by product of a flat fuel tank and the fact that many instrument panels and or instruments are not perfectly squared up to the plane. Too many people also press on the instrument panel when exiting the plane which over time will distort alignment too. My left tank drains 3 times faster than my right. I fly 1/2 ball out to the left and when I'm dome flying my tanks are fairly equal. remember this: The fuel will follow the ball. Usually for most people 1/2 ball out to the faster draining tank makes things fairly equal. If you have a really low fuel tank (lets say the left tank) with lots of fuel still in the right tank you can fly 1 full ball out to the left and the fuller right tank will feed the engine and transfer fuel back into the left tank. It isn't a fast process, but it works very well. Owners with GA aircraft have experienced this and it isn't any thing new. Knowing this will keep you from ever having a fuel issue in either wing. This isn't a big deal, but when this subject is brought up every few years someone makes it one. It's an easy problem to solve and work with. Several have tried to correct it and only a few have won. It is more a function of a flat design fuel tank. CT4ME just used this on his flight down to Mexico. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted March 16, 2015 Report Share Posted March 16, 2015 On my CT, the left tanks seems to drain faster. Maybe I fly with that wing down a bit, but I am conscious of it and try to keep it level. If it sits overnight (or just a few hours) the tanks seem to balance back out, even though I was told there is no crossover tube...anybody know why that is? When I take my plane E-LSA I might investigate adding a LEFT-RIGHT-BOTH fuel valve somewhere above the fuel cutoff valve in the flow. I'd usually leave it on both, but it would be nice to be able to select a tank to drain rather than having to correct a tank imbalance by flying uncoordinated. Link to comment Share on other sites More sharing options...
gbigs Posted March 16, 2015 Report Share Posted March 16, 2015 I leave the fuel selector on BOTH. And don't think about the uneven drain at all. It's never more than three gallons different despite the ball out or flying solo much of the time. Just dip them before or when you suspect you are low and add the fuel and let it go. If you are flying with tanks so low that this would become an issue, you are going to run out one day. Never fly with less than third tanks, and never fly any cross country of 150nm or more with less than 80% full. It is nice to have the header tank, but it only contains 1.3 usable, so depending on it as part of the reserve is tenuous. Link to comment Share on other sites More sharing options...
FastEddieB Posted March 16, 2015 Report Share Posted March 16, 2015 Andy, To keep it simple, how about simple on/off valves on each tank's line? Just keep both on, and if one tank is getting lower, turn it off and let it feed from the other until equal again. Assuming access and reachability to each of the fuel lines from the pilot seat, of course. Link to comment Share on other sites More sharing options...
suntheman Posted March 16, 2015 Report Share Posted March 16, 2015 other day, I checked fuel flow.. with same fuel quantity left & right tank.. I drain, and I found left tank going empty (no really empty but its ok for unsable fuel onboard) after it fuel on right wing going down. Why fuel in left wing going empty first? Dear Roger, I Drain it out on the ground from drain hole (not by engine running)... Fuel in left wing going empty first, then other. how about it? regards Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted March 16, 2015 Report Share Posted March 16, 2015 On my CT, the left tanks seems to drain faster. Maybe I fly with that wing down a bit, but I am conscious of it and try to keep it level. If it sits overnight (or just a few hours) the tanks seem to balance back out, even though I was told there is no crossover tube...anybody know why that is? When I take my plane E-LSA I might investigate adding a LEFT-RIGHT-BOTH fuel valve somewhere above the fuel cutoff valve in the flow. I'd usually leave it on both, but it would be nice to be able to select a tank to drain rather than having to correct a tank imbalance by flying uncoordinated. Your fuel shut off valve is below the 'T' that is the 'crossover' tube. Your CT can balance the fuel in the hangar on a level floor even with the valve closed - or not, some flow more readily than others. Mine equalizes easily and I often add fuel to one side only. Link to comment Share on other sites More sharing options...
FastEddieB Posted March 16, 2015 Report Share Posted March 16, 2015 If someone has one tank that always drains faster... ...how about a small clamp to lightly pinch the hose to a slightly smaller diameter? Something about having to fly along in a constant slip kind of bugs me as a bandaid, and a bandaid that can't help but rob a tiny bit of performance. Link to comment Share on other sites More sharing options...
gbigs Posted March 16, 2015 Report Share Posted March 16, 2015 Other aircraft yell at you to switch tanks on a too frequent basis...the Cirrus for instance has no BOTH switch. The plane monitors the fuel flow and DEMANDS that you switch tanks every 30 minutes or so. So be glad the 'problem' in the FD is inconsequential and the plane will right itself well enough if you don't mess with it. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted March 16, 2015 Report Share Posted March 16, 2015 Andy, To keep it simple, how about simple on/off valves on each tank's line? Just keep both on, and if one tank is getting lower, turn it off and let it feed from the other until equal again. Assuming access and reachability to each of the fuel lines from the pilot seat, of course. That could work...I'm just not sure if two valves makes it simpler than one. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted March 16, 2015 Report Share Posted March 16, 2015 I leave the fuel selector on BOTH. And don't think about the uneven drain at all. It's never more than three gallons different despite the ball out or flying solo much of the time. Just dip them before or when you suspect you are low and add the fuel and let it go. If you are flying with tanks so low that this would become an issue, you are going to run out one day. Never fly with less than third tanks, and never fly any cross country of 150nm or more with less than 80% full. It is nice to have the header tank, but it only contains 1.3 usable, so depending on it as part of the reserve is tenuous. It's a little different when you have a header tank. In a CT *without* a header tank, you'd better be thinking about uneven fuel drain. If you get in a turn at pattern altitude with one tank near dry, you can momentarily unport the fuel pickup and stop the engine. Link to comment Share on other sites More sharing options...
FastEddieB Posted March 16, 2015 Report Share Posted March 16, 2015 If you get in a turn at pattern altitude with one tank near dry, you can momentarily unport the fuel pickup and stop the engine. Not if its coordinated! Which I'm pretty sure ALL of yours must be! Link to comment Share on other sites More sharing options...
FlyingMonkey Posted March 16, 2015 Report Share Posted March 16, 2015 Your fuel shut off valve is below the 'T' that is the 'crossover' tube. Your CT can balance the fuel in the hangar on a level floor even with the valve closed - or not, some flow more readily than others. Mine equalizes easily and I often add fuel to one side only. That's what I figured...there is no balance tube per se, but if there is a T before the valve then the effect is the same, at least over long periods where the plane is level, like in a hangar overnight. Thanks for confirming. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted March 16, 2015 Report Share Posted March 16, 2015 Not if its coordinated! Which I'm pretty sure ALL of yours are! LOL. Yes, of course. 100%. But in a slip to land... Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted March 16, 2015 Report Share Posted March 16, 2015 A partial restriction is a bad idea. We inspect to guarantee adequate minimum flow on both sides. You wouldn't want to 'pinch' down below what your engine can consume WOT plus a safety margin. Pinching would be an allowance for a binnacle that is askew, better to learn where strait and level is and remain balanced. Your sight tubes and a little rudder work can confirm if your ball is correct. Link to comment Share on other sites More sharing options...
Tom Baker Posted March 16, 2015 Report Share Posted March 16, 2015 I know Fast Eddie won't like this, but the landing issue you experienced can be exaggerated by using more than 15° flaps. Link to comment Share on other sites More sharing options...
Roger Lee Posted March 17, 2015 Report Share Posted March 17, 2015 First you can not put valves and clamps in line because it's an SLSA and no one at FD would ever approve this. In the early days they had fuel valves. Too many couldn't remember to switch tanks so they ran out of fuel and crashed. That's why we have the system we have in some CT's. I think FD must be trying to see if people are any smarter with the new fuel shut offs in the new LS. Although they really didn't trust the pilot because they put a header tank in with a low fuel alarm to wake them up. I have seen some CT's drain one wing on the ground faster than the other and they did not have any restrictions. I don't have a great answer for you. One just seems to flow easier. Many times I hear of people telling me their hangar floor is not level. I would bet most are level enough to not cause a fuel transfer. That would take a pretty cross-eyed concrete mason. I have put 8' level with even longer straight edges on a lot of floors and they are pretty close. What I do find that most owners don't know is that one side of their plane is sits lower than the other for a couple of different reasons. They don't know how to measure or don't take the time to consider it may be the plane and not the floor. Things like bent axle receptacles, slightly bent gear legs (most common), fuselage settling and low tires on one side(it doesn't have to be flat) Link to comment Share on other sites More sharing options...
FastEddieB Posted March 17, 2015 Report Share Posted March 17, 2015 First you can not put valves and clamps in line because it's an SLSA and no one at FD would ever approve this. Roger, I was pretty much involved in a dialog with Andy, who had proposed trying to solve the problem after going Experimental. Link to comment Share on other sites More sharing options...
Jim Meade Posted March 17, 2015 Report Share Posted March 17, 2015 Positive fuel management seems like a good objective to me, but I'm used to flying the Cessna 402 which had six tanks, with a sequence of use that was dictated by which had the fuel return lines and which had only a pump and no gauges. Somewhat like the Twin Comanche, although not identical. It was not a big deal. When I flew my T210, fuel management was a tool that was useful for influencing trim. Especially with modern electronics, alarms and fuel monitoring systems, fuel management shouldn't be a major deal. Even steam gauge planes should be relatively easy to manage. Link to comment Share on other sites More sharing options...
FredG Posted March 17, 2015 Report Share Posted March 17, 2015 If one fuel tank drains faster than the other fuel tank (with the airplane on the ground and other variables, such as the amount of fuel in the two tanks equal), then the fuel lines from that wing have [edit] less resistance to flow than the fuel lines from the other wing. Resistance to the flow of a fluid through a tube is a function of the fourth power of the radius of the tube, so small changes in fuel lines have disproportionately large effects on flow. Link to comment Share on other sites More sharing options...
Roger Lee Posted March 17, 2015 Report Share Posted March 17, 2015 Hi Eddie, I saw a CT that went experimental and tried to do this very thing. It was a cluster. I would say keep things simple and don't make it worse or more complicated than it is or make a mountain out of a mole hill. Fuel management in a CT is easy. Many people that try fixes and make something un-salable just like the last CT guy did. The fix without all the extra parts is to push a little peddle so the ball is 1/2 out to the faster draining wing. If it was an easy fix FD would have either fixed it on later models or allowed retro fits. There is another CT at my field that had been damaged at one time. An A&P mechanic worked on it and did whatever he wanted. He thought he could make it better and tried to fix things. Now it can't be annual-ed and I won't touch it and it can't go experimental LSA because a DAR won't touch it. It would take upwards to $6K-$7K to put it back again. If they would have kept it simple and just put it back like they found it the owner wouldn't be in his mess. Sometimes simple is just better even though it isn't perfect. Link to comment Share on other sites More sharing options...
suntheman Posted March 17, 2015 Report Share Posted March 17, 2015 Ok thanks all, I'll check fuel system/fuel line find if any ressistance, clean fuel cap/fuel vent, & try to fly with 1/2 ball to faster tank. I'll keep n update Regards Link to comment Share on other sites More sharing options...
FlyingMonkey Posted March 17, 2015 Report Share Posted March 17, 2015 Hi Eddie, I saw a CT that went experimental and tried to do this very thing. It was a cluster. I would say keep things simple and don't make it worse or more complicated than it is or make a mountain out of a mole hill. Fuel management in a CT is easy. Many people that try fixes and make something un-salable just like the last CT guy did. The fix without all the extra parts is to push a little peddle so the ball is 1/2 out to the faster draining wing. If it was an easy fix FD would have either fixed it on later models or allowed retro fits. There is another CT at my field that had been damaged at one time. An A&P mechanic worked on it and did whatever he wanted. He thought he could make it better and tried to fix things. Now it can't be annual-ed and I won't touch it and it can't go experimental LSA because a DAR won't touch it. It would take upwards to $6K-$7K to put it back again. If they would have kept it simple and just put it back like they found it the owner wouldn't be in his mess. Sometimes simple is just better even though it isn't perfect. I agree Roger, that simple is often better. And I also agree that fuel management in a CT is not difficult. In bringing up adding a fuel valve, I was only talking about looking at things and seeing if it even made any sense. It very well might not. Knowing how the fuel lines run in the CT, it would be hard to do without running additional fuel lines through the cockpit, which is not really making things better in my mind. I don't like having to fly out of coordination to manage fuel, but it might well be the best option. As you said, simple is not always perfect but might still be better that the other options. Link to comment Share on other sites More sharing options...
Roger Lee Posted March 18, 2015 Report Share Posted March 18, 2015 Hi Andy, I was fishing a little. Toss the lure out and see what bites. :huh: Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.