deadstick Posted April 17, 2010 Share Posted April 17, 2010 After some info regarding the fuel system in the Gazelle, I and a friend fly 2 different gazelles and one will feed from the port tank and the other feeds from the STBD, both suck down to around 5-7-7 litres before they start feeding from the other tank. What I want to know is- is this normal for the type and what would cause it? balnced flight is maintained and I am not sure if its effected by the boost pump or not. Link to comment Share on other sites More sharing options...
Guest Wigg Posted April 17, 2010 Share Posted April 17, 2010 When this first happened with our Gazelle thought life was soon going to finish but found out it has always done this. It is a bit disconcerting at first but live with it now . Cheers John Link to comment Share on other sites More sharing options...
facthunter Posted April 17, 2010 Share Posted April 17, 2010 Uneven. This appears to be quite common with Gazelle's. I am inclined to put a lot of it down to flying with slight unbalance. It doesn't take much. I have seen a maximum of about half a tank difference, and never inclined to totally be happy with it. This has been discussed before and a link to it might be a good idea. Nev Link to comment Share on other sites More sharing options...
Ultralights Posted April 17, 2010 Share Posted April 17, 2010 Jabiru 170s, well, our schools one does the same. actually its more common than not, i cant remeber any aircraft i have flown that drained both tanks evenly, unless you turn one tank off, and drain for 1 for 15 mins then regularly change tanks. but im not a fan of closing any tanks off inflight, unless your flying something with 4 tanks etc. Link to comment Share on other sites More sharing options...
Neil_S Posted April 17, 2010 Share Posted April 17, 2010 Hi Deadstick, Yup - happens all the time in my Gazelle. Starboard tank first, then port. Has always done so. Our best guess is uneven venting, but it doesn't matter as they cross-feed anyway. A friend has the same thing happen in his Jab 160, but the other way round, so I don't think it is confined to Gazelles by any means. Cheers Neil Link to comment Share on other sites More sharing options...
barandbrew Posted April 19, 2010 Share Posted April 19, 2010 HI Deadstick I have had this problem with my Gazelle since I purchased it 6 years ago. On the weekend we did a 100 hr service I mentioned this to my LAME an told him that I found when swaping the fuel caps over it reversed the drain. I had been expermenting with the position of the vents to air flow as it is obviously a pressure problem on inspection he found that the spring metal that holds the caps secure is made of different material one has a strong spring action the other weak. We adjusted this and I hope it will cure my problem . I will let you know when next I fly. Hope this helps as it has been bugging me since I bought the aircraft John Link to comment Share on other sites More sharing options...
barandbrew Posted April 30, 2010 Share Posted April 30, 2010 HI Deadstick Flew yesterday with the adjusted caps and the fuel drain is nearly even Hope this helps Regards John:thumb_up: 1 Link to comment Share on other sites More sharing options...
rk67 Posted April 30, 2010 Share Posted April 30, 2010 breathers first thing I would do is check breathers, our gazelle feeds evenly Link to comment Share on other sites More sharing options...
deadstick Posted April 30, 2010 Author Share Posted April 30, 2010 balance Thanks for the reply's, I am certain it has to do with balance after testing yesterday on a 1.5 hr flight I noticed the aircraft is out of balance it wants to roll left and slip so every time I was looking around when my eyes were back inside it would be slightly out. Link to comment Share on other sites More sharing options...
Keith W Posted December 15, 2015 Share Posted December 15, 2015 My Gazellewill use nearly all the fuel from the port tank before it starts taking fuel from the starboard tank, also I get fuel streaks on the starboard wing, not much but enough to be a nuisance, removed the filler and checked the seal everything ok, only thing I can think of is a bit of a vacuum sucking some fuel out through the breather or the tank some how getting pressurised enough to force fuel out open to suggestions thanks Keith. Link to comment Share on other sites More sharing options...
frank marriott Posted December 15, 2015 Share Posted December 15, 2015 "stand on the empty tank" hold about half a ball out and wait, the fuel will gradually balance. Standard practise even in a C208 which has a maximum listed balance limitation [with floats anyway] 1 Link to comment Share on other sites More sharing options...
OZJohn Posted December 15, 2015 Share Posted December 15, 2015 I find it is usually to do with the vents. One is in a slightly different pressure area than the other. John. Link to comment Share on other sites More sharing options...
biggles Posted December 15, 2015 Share Posted December 15, 2015 I find it is usually to do with the vents. One is in a slightly different pressure area than the other.John. With the current Jab set-up , the vent holes are forward facing, therefore subjected to the same degree of air pressure .... Bob Link to comment Share on other sites More sharing options...
Neil_S Posted December 15, 2015 Share Posted December 15, 2015 My Gazellewill use nearly all the fuel from the port tank before it starts taking fuel from the starboard tank, also I get fuel streaks on the starboard wing, not much but enough to be a nuisance, removed the filler and checked the seal everything ok, only thing I can think of is a bit of a vacuum sucking some fuel out through the breather or the tank some how getting pressurised enough to force fuel out open to suggestions thanks Keith. Hi Keith, Our Gazelle did/does exactly the same. As noted previously on this thread we guessed slightly different venting, but as it was never a problem we did not stress about it. Cheers, Neil Link to comment Share on other sites More sharing options...
Pearo Posted December 15, 2015 Share Posted December 15, 2015 Cessan 172/182 is the same. I am only new to the game though. Put a heavy on one side and a light on the other get the same problem. Do circuits get the same problem. Switch tanks no issues with fuel starvation. I am guessing this is not unique to the gazelle. Link to comment Share on other sites More sharing options...
Sav 4352 Posted December 15, 2015 Share Posted December 15, 2015 My Savannah was the same, seemed to depend on the crosswind, put a tap on both tank and now use the left then the right, problem solved. Link to comment Share on other sites More sharing options...
Keith W Posted December 16, 2015 Share Posted December 16, 2015 Thanks for the replies every body, I'm not that worried about the uneven fuel drain it's the slight dry fuel streaks down the wing that I don't like, the only place I can think of where it's coming from is out of the vent, wether it's being sucked out or pushed out I don't know, I thought it might be related that the side that drained last had the fuel s Link to comment Share on other sites More sharing options...
facthunter Posted December 16, 2015 Share Posted December 16, 2015 My experience with school aircraft, the variation seems to be related mostly to who last flew it. If you have a full tank for whatever reason it's close to venting fuel out. (Unless you have a very well designed vent system.) Nev Link to comment Share on other sites More sharing options...
Guernsey Posted December 16, 2015 Share Posted December 16, 2015 Not sure about some aircraft but it does remind me of my marriage (55 yrs), Sometimes my wife vents her anger and some times I vent mine, but it all seems to balance out in the end and we seem to fly along quite nicely. . Well balanced Alan. Link to comment Share on other sites More sharing options...
biggles Posted December 16, 2015 Share Posted December 16, 2015 Not sure about some aircraft but it does remind me of my marriage (55 yrs), Sometimes my wife vents her anger and some times I vent mine, but it all seems to balance out in the end and we seem to fly along quite nicely. .Well balanced Alan. Yeah Alan , I know a bloke on this site that is 'well balanced' also , he has a chip on both shoulders ..... Bob Link to comment Share on other sites More sharing options...
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