Roger Lee Posted August 23, 2014 Report Share Posted August 23, 2014 I don't have standard vents and my left wing drains faster with the original vent or my vent. Changing position of the vents relative to the wing has never changed anything. Link to comment Share on other sites More sharing options...
Rogerck Posted August 23, 2014 Report Share Posted August 23, 2014 Hi Roger, I understand you've done a fair amount of testing with the fuel vents, but in my particular case, when I switched the vent tubes the fuel usage changed with the vents. That seems pretty telling. Is it possible to remove the upper portion of the vent to view the vent orifice? Roger Kuhn Link to comment Share on other sites More sharing options...
Roger Lee Posted August 23, 2014 Report Share Posted August 23, 2014 I have never tried. Link to comment Share on other sites More sharing options...
WmInce Posted August 23, 2014 Report Share Posted August 23, 2014 Yesterday, I realigned my vent posts on my CTSW fuel caps (green dot forward). They were a bugger to turn, had previously been over tightened. Thank you Roger Lee for your suggestions to free them up, it worked perfectly. After backing off the lock nut on top, around the shaft vent post, I used a small pair of vice grips around the shaft post to unscrew it, being careful not to collapse the shaft. Following the realignment, I also blew air through the cap bottoms'. The pressure on both caps was about the same. All that withstanding, my tanks have not been emptying evenly either. My method of fuel balance is trim control and adjusting bank angle. Link to comment Share on other sites More sharing options...
FredG Posted August 23, 2014 Report Share Posted August 23, 2014 Bill, I had more fuel in one tank than the other after a long flight until my mechanic checked and corrected the slight tilt of my Dynon. If the Dynon is not level in comparison to the wings, then flight with the ball centered results in one wing flying slightly higher than the other wing. Fuel will simply flow downhill in that case, and result in uneven volumes at the end of a flight. Don't know if you have checked for this. Link to comment Share on other sites More sharing options...
Tom Baker Posted August 23, 2014 Report Share Posted August 23, 2014 In most parts of the country you can just look at the wing tips and see if you are level. I do this to make sure my wings are level when going cross country on autopilot, and I don't worry about the ball. Link to comment Share on other sites More sharing options...
Jim Meade Posted August 23, 2014 Report Share Posted August 23, 2014 In most parts of the country you can just look at the wing tips and see if you are level. I do this to make sure my wings are level when going cross country on autopilot, and I don't worry about the ball.Tom, I've been told to do this before and have never felt it worked for me. Probably a good idea for those who can make it work. I had a fuel imbalance problem on a long trip recently. I was careful to trim to keep the ball centered. Checked yesterday and found the ball considerably off level, so I adjusted the Dynon and the muchroom and it is much better. (I need to get my SkyView in and solve this problem). A month or so ago, I was doing some work on the panel and found a piece of wood had been fashioned into a crude shim and placed under the mushroom where it fits on the tunnel. I'm betting now that that shim was to tilt the muchroom up so the Dynon ball was level, as I never noticed it to be badly out of level before. Link to comment Share on other sites More sharing options...
WmInce Posted August 24, 2014 Report Share Posted August 24, 2014 Bill, I had more fuel in one tank than the other after a long flight until my mechanic checked and corrected the slight tilt of my Dynon. If the Dynon is not level in comparison to the wings, then flight with the ball centered results in one wing flying slightly higher than the other wing. Fuel will simply flow downhill in that case, and result in uneven volumes at the end of a flight. Don't know if you have checked for this. Fred, Which Dynon are you talking about? I have SkyView displays, which gets their information from the ADAHRS in the wing, so I don't think adjusting the display attitude makes any difference. I see where you are coming from though. Thanks. Link to comment Share on other sites More sharing options...
WmInce Posted August 24, 2014 Report Share Posted August 24, 2014 In most parts of the country you can just look at the wing tips and see if you are level. I do this to make sure my wings are level when going cross country on autopilot, and I don't worry about the ball. I do the same during cross country also, but being wings level and out of trim (ball not centered) still affects the fuel feed, as one wing will be trailing, relatively, to the other wing, around the vertical axis. Can someone else comment on this? I wish FD would install a limited flow, crossfeed line, between the two tanks, which would allow fuel to be balanced during level flight situations. IMHO, the fuel system is the weakest part of the airplane engineering. Link to comment Share on other sites More sharing options...
Roger Lee Posted August 24, 2014 Report Share Posted August 24, 2014 Hi Bill, You can balance the fuel system depending on which plane we are talking about. If one wing drains faster than the other then fly 1/2 ball out to the fastest draining wing. That will equal the flow. If you want to actually transfer fuel from one side to the other fly a full ball ouit to the fastest draining wing or whichever wing you want the fuel to move to.. Link to comment Share on other sites More sharing options...
WmInce Posted August 24, 2014 Report Share Posted August 24, 2014 Hi Bill, You can balance the fuel system depending on which plane we are talking about. If one wing drains faster than the other then fly 1/2 ball out to the fastest draining wing. That will equal the flow. If you want to actually transfer fuel from one side to the other fly a full ball ouit to the fastest draining wing or whichever wing you want the fuel to move to.. Thanks Roger. . . . . Link to comment Share on other sites More sharing options...
Anticept Posted August 24, 2014 Report Share Posted August 24, 2014 I wish FD would install a limited flow, crossfeed line, between the two tanks, which would allow fuel to be balanced during level flight situations. IMHO, the fuel system is the weakest part of the airplane engineering. That is a lot more engineering than you think. I am not sure about easa, but in FAA certification, a crossfeed line requires a manual shutoff. There IS a crossover line for air pressure though. It gets kinked really really easy. Link to comment Share on other sites More sharing options...
FastEddieB Posted August 24, 2014 Report Share Posted August 24, 2014 I do the same during cross country also, but being wings level and out of trim (ball not centered) still affects the fuel feed, as one wing will be trailing, relatively, to the other wing, around the vertical axis. Can someone else comment on this? I'll bite... ...why would a "trailing" wing, if level with the other, flow either more or less fuel? And now that I think of it, is it even possible to have wings level and ball not centered if not turning? Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted August 24, 2014 Author Report Share Posted August 24, 2014 I'll bite... ...why would a "trailing" wing, if level with the other, flow either more or less fuel? And now that I think of it, is it even possible to have wings level and ball not centered if not turning? The ball will be centered unless it is in need of adjustment. Some CTs don't have a physical ball and no provision for adjustment. Some CTs can lose their adjustments by bumping and moving the binnacle. If your ball is in need of adjustment and you none the less cruise with it in the middle you will have a low/trailing wing and you will use more fuel from the high wing. Link to comment Share on other sites More sharing options...
WmInce Posted August 24, 2014 Report Share Posted August 24, 2014 . . . "I'll bite... ...why would a "trailing" wing, if level with the other, flow either more or less fuel?" . . . I'll bite on your bite.Because of the location of the tank drain, being located at the forward part of a tank, which may result in a situation where the drain is uncovered during certain flight attitudes, around the vertical axis, in less than a full tank scenario. This is more of a question, than a statement. Link to comment Share on other sites More sharing options...
FastEddieB Posted August 24, 2014 Report Share Posted August 24, 2014 Sure. But if the wings are level, they should feed evenly in level unaccelerated flight. Reducto ad absurdum, even if the plane was being somehow being pushed through the air with it's nose 90° to the left or right, if the wings were level, gravity would effect them both equally. Now the vents could factor into this, but that seems to be another issue entirely. Link to comment Share on other sites More sharing options...
WmInce Posted August 24, 2014 Report Share Posted August 24, 2014 Sure. But if the wings are level, they should feed evenly in level unaccelerated flight. Reducto ad absurdum, even if the plane was being somehow being pushed through the air with it's nose 90° to the left or right, if the wings were level, gravity would effect them both equally. Now the vents could factor into this, but that seems to be another issue entirely. Concur.Getting back to the vents, that's where the thread started. Link to comment Share on other sites More sharing options...
FredG Posted August 24, 2014 Report Share Posted August 24, 2014 Bill, yes, I have the old school Dynon D100, and it was mounted out of level with respect to the wings. As a result, the plane flew in a subtle slip when the ball was centered. (Eddie, that is one way the ball can lie to the pilot, i.e., faulty installation or what CT calls "needs adjustment"). Fuel simply flowed downhill to the slightly lower wing, only I had no idea that it was low. I do not know what is done during Skyview installation to center the ball when the wings are level, but conceptually, the same problem has to be prevented. On reading several posts above, it seems that there is persistent mixing of concepts here. One concept is that one wing supplies more fuel to the engine than the other (it really does flow more fuel), and in doing so leads to an imbalance in fuel volumes between the tanks on landing. If that is happening, then there is a partial obstruction somewhere in the fuel system from that tank (obstructed fuel screen in the tank, blockage in a fuel line or some other problem that is creating unequal flow). I see now way that tipping the wings will alter the flow rate (since the reason for the difference in flow rates doesn't change when I tip one wing). If my plane really flowed faster from one wing than the other, I would want to know why and I would want to fix it. The other concept is that, in an airplane with a connection between wings tanks, fuel will flow downhill (to the tank in the low wing) when the plane is flown in a subtle (or not so subtle) slip. The plane doesn't really use more fuel from the tank in the higher wing, it used the same amount of fuel from that tank as it did from the tank in the low wing. It simply transferred fuel to the lower wing from the higher wing while in flight. On my plane, this second reason is why I was having unequal fuel on landing. One tank had more fuel in it than the other, after a long flight, because the fuel flowed downhill to the lower tank, not because of a difference in flow rates from the two tanks. Once my D100 was aligned with the wings, my L vs R fuel levels were very similar regardless of flight duration (as long as I flew with the ball centered). BTW, when I first started dealing with this problem, I switched the fuel tank filler caps left for right, and realigned the vents with green dots forward. No change at all in the problem. Link to comment Share on other sites More sharing options...
Jim Meade Posted August 24, 2014 Report Share Posted August 24, 2014 The D100 has a built in ADAHRS, so the unit must be level. The Skyview ADAHRS is a separate module. The Skyview itself does not have to be level. You have to install the ADAHRS module level. Link to comment Share on other sites More sharing options...
Rogerck Posted August 24, 2014 Report Share Posted August 24, 2014 Try soaking the tops of the fuel vents in MEK (or other solvent) overnight then blowing out the vents with compressed air. (You'll have to replace the green dot.) For our CT, this resulted in close to even fuel tank usage versus much higher left wing usage beforehand. As mentioned in an earlier post, I originally switched the vents wing to wing and the higher wing fuel usage changed with the vents. Apparently, uneven fuel flow can be caused by a difference in vent back pressure. The vents have a tiny opening with no air filter proceeding them. Cleaning them out is now part of our maintenance procedure. Roger Kuhn Link to comment Share on other sites More sharing options...
Roger Lee Posted August 24, 2014 Report Share Posted August 24, 2014 You may have had some bug parts or part of a spider web in one. Link to comment Share on other sites More sharing options...
WmInce Posted August 24, 2014 Report Share Posted August 24, 2014 Great tips guys. Thanks. . . . . Link to comment Share on other sites More sharing options...
Anticept Posted August 25, 2014 Report Share Posted August 25, 2014 Our aircraft are supposed to have carry-through lines between the tanks to assist in balancing the air pressure for the gravity feed system. Make sure those lines are clear too. Link to comment Share on other sites More sharing options...
Tom Baker Posted August 25, 2014 Report Share Posted August 25, 2014 There are no lines on a SW. That was a change with the LS. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted August 25, 2014 Report Share Posted August 25, 2014 There are no lines on a SW. That was a change with the LS. But there is a Y connection somewhere above the fuel valve, right? Doesn't that serve a similar purpose? Link to comment Share on other sites More sharing options...
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