Jim Meade Posted July 22, 2013 Report Share Posted July 22, 2013 I offer the following observation just for general information. I am not trying to make any point. Typically I teach people to stick the tank straight up and down no matter what airplane or measuring tool (Fuel Hawk, dipstick, etc.) they are using. CTSW with 10.5 gallons in left tank and 10.0 in right tank sticking as described. Stick by putting the stick to the rear of the tank (handle on top is as far forward as possible). Reading was about 12 gallons. Stick by putting the stick as far forward as possible (handle was to the rear). A little less than 10 gallons. Sticking with the handle to either side, also about 10 gallons. I didn't try to get too precise so don't take these values as gospel. My take away on this exercise is that the most accurate reading is probably with the device straight up an down. Other readings were not too far off with the exception that putting the stick all the way to the back read at least 1.5 gallons higher. I have no idea if it would always read 1.5 gallons high at any fill level, or if it would change as the tank was fuller or less full. Of course, we will all stick with reasonable care. In particular, we don't want to have the bottom of the dip stick aggressively to the back of the wing. Link to comment Share on other sites More sharing options...
sandpiper Posted July 22, 2013 Report Share Posted July 22, 2013 I think, that unless you have calibrated your dip stick, use it only as an approximation. My reason - today I drained my tanks so I could change my fuel sight tubes. Before draining I had 3 in the left and 4 in the right per my dip stick. But, I only drained out about 6 gallons. Maybe some is still in the tanks - I didn't stick them after draining. I'll check tomorrow. Right now I'm too lazy to go to the hangar - which is attached to my house :blush:. Talk about lazy!! Link to comment Share on other sites More sharing options...
Jim Meade Posted July 22, 2013 Author Report Share Posted July 22, 2013 I agree with your caution to use the dip stick as an approximation. The CT says it has capacity of 17 per side, 16.5 usable, so your experience may be about in line with what the manufacturer says. 7 gallons per the stick and 6 in the bucket works out per the book. A good thing for all of us to remember. Link to comment Share on other sites More sharing options...
Roger Lee Posted July 22, 2013 Report Share Posted July 22, 2013 Something else to consider. Since we have flat fuel tanks it would only take the plane to be on a very slight tilt from one wing to the other to get a false reading as one side's fuel goes to the out board side of one wing giving it a higher level and the other wing the inboard side giving it a lower reading. This slight tilt would not even have to be noticeable. It could be caused by an uneven surface or one gear leg with a slight bend you haven't noticed. Want to be a little shocked take a tape measure next time you are at your plane and measure from the floor to the wing tip point or other places on the wing and I would bet many have one wing higher than the other due to the floor or a slight tweak on one gear leg. Link to comment Share on other sites More sharing options...
CT_MATT Posted July 23, 2013 Report Share Posted July 23, 2013 Roger, I notice that when looking from the rear, my gear legs do not look symmetric at all (CTLS) Which may be why the measurement you mention is off on my plane. Is this common? Link to comment Share on other sites More sharing options...
Roger Lee Posted July 23, 2013 Report Share Posted July 23, 2013 Yes, many have either uneven floors and they have had a firm enough landing to put a tiny tweak in the gear to make one wing 1"-2" lower out at the wing tips. Sometimes it's noticeable and sometimes not so much. You can check things by putting an 8' level on the floor then on top of the center fuselage. You can then measure wing tips from the floor. Link to comment Share on other sites More sharing options...
Jim Meade Posted July 23, 2013 Author Report Share Posted July 23, 2013 Something else to consider. Since we have flat fuel tanks it would only take the plane to be on a very slight tilt from one wing to the other to get a false reading as one side's fuel goes to the out board side of one wing giving it a higher level and the other wing the inboard side giving it a lower reading. Excellent point. I know how atrocious the sight gauges are, but if they were clear and accurately marked,, would the sight gauge reading compensate for the tilt? If one wing is down, would it read low but the higher wing read falsely high but then average out? I'm thinking out loud and asking, not stating my conclusion. The next point, though, is, if the sight gauges were actually accurate enought to be trustworthy, would one ever need to stick the tank? I would really like to do something to make the sight gauges usable. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted July 23, 2013 Report Share Posted July 23, 2013 I seldom stick the tank, the site tubes are quite accurate but you do need to know how to read them. While parked in the hanger your fuel levels should equalize, either slowly or quickly. If they don't read the same when they have time to equalize then your hangar floor or gear legs are suspect. In flight you have to test, yaw left and right to confirm there is no slip or skid 1st. When slipping the hi/lo readings do not come close to a correct average in my experience. Link to comment Share on other sites More sharing options...
Jim Meade Posted July 23, 2013 Author Report Share Posted July 23, 2013 CT, well (it's sight tube, not site tube) how do you read them accurately? First, they're opaque. Second, I can't get my head around there. Third, the graduations aren't marked well. Yes, I know I'm whining. But, I am serious about wanting them to work better and am eager to hear any ideas. Didn't someone use Jabiru sight tubes? I have to pull my wings this fall and would love to do something better than what FD did, which I think is a sop to some bureaucrat. Link to comment Share on other sites More sharing options...
Roger Lee Posted July 23, 2013 Report Share Posted July 23, 2013 Use clear poly tubing and not the yellow Tygon tubing which makes reading the fuel level almost impossible after a few hours of fuel stain has made them even worse than when new. When I do a wing pull I always put new clear sight tubes on. Then you can pour any fuel quality you want equally into each wing and mark the sight tubes with a black magic marker. You reall don't need to get carried away with marks every two gals. The top of the sight tube is right around 10.5 gals. You could mark 2.5 and 5 gals and be perfectly good to go. If it gets to 2.5 gals of fuel in flight on each side you need to be on the ground to re-fuel. While flying if you're not sure about the fuel level because you may be a slightly out of trim just move your controls and see what the fuel in the tubes does. If you can't see because of the seatbelt then loosen it for a few moments or slide a shoulder out to look. Using a flashlight with darkened sight tubes will help see the level. The sight tubes should not darken too bad until the next wing inspection. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted July 23, 2013 Report Share Posted July 23, 2013 CT, well (it's sight tube, not site tube) how do you read them accurately? First, they're opaque. Second, I can't get my head around there. Third, the graduations aren't marked well. Yes, I know I'm whining. But, I am serious about wanting them to work better and am eager to hear any ideas. Didn't someone use Jabiru sight tubes? I have to pull my wings this fall and would love to do something better than what FD did, which I think is a sop to some bureaucrat. Keep tubes clear by replacing with clear tubing. Mark the tubes yourself. If you can't move your head carry a mirror. As I walk in the hangar the first thing I do is grab a wingtip and move it, then look in the cockpit at the site tube. I either know how much fuel I have or that I have more than 13 gal in the side I am checking. From the hangar floor I can see higher up on the tubes. =================================== FLYING WITH SIGHT TUBES You can realize fuel starvation with fuel on board. If you can see fuel so can your engine. If you are fuel critical slip to keep fuel at the wing root and when that fuel goes away, land. When slipping the fuel follows the ball Link to comment Share on other sites More sharing options...
Jim Meade Posted July 23, 2013 Author Report Share Posted July 23, 2013 I'm talking about making an accurate determination of fuel remaining for the purposes of flight planning and fuel management. I guess that one issue is how accurate is accurate enough and that is a personal decision, so I think that what works for me may not be comfortable for you and vice versa. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted July 23, 2013 Report Share Posted July 23, 2013 There is error in reading sight tubes in the best of conditions and there is error in dipping as well. My bladder is good for 2 hours and my plane holds 6 hours, I never plan anything precisely. Link to comment Share on other sites More sharing options...
Jim Meade Posted July 24, 2013 Author Report Share Posted July 24, 2013 There is error in reading sight tubes in the best of conditions and there is error in dipping as well. My bladder is good for 2 hours and my plane holds 6 hours, I never plan anything precisely. This works well for many casual pilots who are not worried about max distance or weight, but when one is flying charter or at the edge of the envelope and fuel counts, it's nice if one has and occasionally practices the skills of precise fuel management. We used to routinely land light jets right at the FAA minimum. It was routine. It was not a big deal. But, it did take precise planning, good instrumentation and good execution. It was probably easier than with little, bumbly light airplanes that may have a 10% headwind change (although I do remember one time on at trip to Denver at FL360 seeing 125 knots on the nose). Link to comment Share on other sites More sharing options...
sandpiper Posted July 24, 2013 Report Share Posted July 24, 2013 I put new sight tubes in yesterday and marked them at 2 gal. and 7 gal. I had a 2 and 5 gal. jugs so that's why 2 & 7. Anyway, with 7 gal. in, each wing sticked at 7.5. So, as in my post above, my stick is optimistic. No smart comments!! Link to comment Share on other sites More sharing options...
Jim Meade Posted July 24, 2013 Author Report Share Posted July 24, 2013 John, I hope your wings were level. Seriously, I enjoy and benefit from the discussion. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted July 24, 2013 Report Share Posted July 24, 2013 I treat my CTSW the same way I treat my car. When it gets close to empty I fill it up. This method has worked well for the first 600 hours. I have a light CT and there is always room for 200lbs of fuel. Link to comment Share on other sites More sharing options...
sandpiper Posted July 24, 2013 Report Share Posted July 24, 2013 In the old days it was always fly the plane, fill the plane before you put it away. But, then, in AK I never had a hangar. With the CT, I put gas in when I need to. It's seldom full. Usually not more than 25 gallons which exceeds my bladder by 2 hours. Never a problem in 6 years. Yes, my wings were level, or at least close. Link to comment Share on other sites More sharing options...
207WF Posted July 25, 2013 Report Share Posted July 25, 2013 With the thin tanks on the CT the stick is very sensitive to any fuel movement, and if the fuel has not completely stopped moving when you stick, it will read too high. Also, I have noted when fueling from cans that after I put my 5 gallons in one side, starting with a balanced load, the imbalance will make the heavy side stick show one more gallon than I have in there, while the light side will stick one gallon too low. WF Link to comment Share on other sites More sharing options...
FlyingMonkey Posted July 25, 2013 Report Share Posted July 25, 2013 If you are planning to run the airplane to maximum endurance and right up to VFR minimums, then you shouldn't be using sight tubes alone, you should have a fuel flow meter and perhaps a totalizer, and a really good stopwatch. Link to comment Share on other sites More sharing options...
Jim Meade Posted July 25, 2013 Author Report Share Posted July 25, 2013 If you are planning to run the airplane to maximum endurance and right up to VFR minimums, then you shouldn't be using sight tubes alone, you should have a fuel flow meter and perhaps a totalizer, and a really good stopwatch. This is all good, but totalizers don't help when you have a fuel leak or it syphons out the vent or in any other way gets lost, or if the impeller goes bad or any of the other things that can happen. Happened to my herbicide sprayer this year. I do use and trust a totalizer, but I like an accurate "just in case" system. Link to comment Share on other sites More sharing options...
Znurtdog Posted September 9, 2013 Report Share Posted September 9, 2013 Has anyone tried to buy a replacement 'dipper' for the SW? FD wants $135 for theirs... Link to comment Share on other sites More sharing options...
FlyingMonkey Posted September 9, 2013 Report Share Posted September 9, 2013 Has anyone tried to buy a replacement 'dipper' for the SW? FD wants $135 for theirs... If I needed a new one I'd make one. Drain fuel tanks completely, then pour in a known quantity, mark the stick to that level, repeat until tank full. Do it for each side. Since this will be done for your exact aircraft and exactly how you stick the tanks, it will be far more accurate than the generic FD stick. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted September 9, 2013 Report Share Posted September 9, 2013 If I needed a new one I'd make one. Drain fuel tanks completely, then pour in a known quantity, mark the stick to that level, repeat until tank full. Do it for each side. Since this will be done for your exact aircraft and exactly how you stick the tanks, it will be far more accurate than the generic FD stick. You could clamp the line to the other tank to keep fuel from transferring while you are trying to get accurate measurements. Link to comment Share on other sites More sharing options...
George in San Diego Posted September 25, 2013 Report Share Posted September 25, 2013 Just noticed this thread. I wondered if it is possible to have a tweaked leg as I always have more fuel in left tank. Will need to get one of those 8' Levels Roger mentioned but I actually did measure wingtip to floor and its low on left side. Hmm. The mechanics discovered little minor crunchies under the left upper leg fairig at Annual. Fixed per FD instructions for $400. Perhaps there's more to this. I know original owner had landing troubles now and then. No one suggested bent landing gear though. How DO you put a permanent kink in a composite gear leg? More importantly, how do you Fix it? Link to comment Share on other sites More sharing options...
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