Thread: Fuel Balance

Was returning late this afternoon from MCW (Mason City Iowa) back to home base PVB (Platteville Wi) 139nm maybey. Had a total of 12 gallons on departure. Enroute the rt tank got down to 2 gallons in smooth air with autopilot and level wings according to the Dynon Horizon. Pushed a half ball of left rudder since left tank had 7 gallons, for about 20 mins. Rt tank kept showing 2 gallons as left tank was way up in the window due to the bank angle. When I leveled out and waited for the slosh tanks to find their true amount, I had only 1.5 gallons in the Rt tank and 6.5 in the Left. Now I had to fly with a little Rt rudder the rest of the trip home. The point of the post is you can utilize all the fuel in both tanks, just dont get scared when you tilt the wing up for the fuller tank and the empty tank gets emptier, due to the slosh tank draining to the outside tank away from the site tube while you are transfering fuel. As long as there is fuel over either tank suction line the engine will run just fine. I think Roger coined "push to empty" as to which rudder to push to get fuel from the fuller tank. "Empty" and "airplanes", are two words that dont sound good in the same sentence, Maybey push "rudder to run" might work also. I dont think the SW has slosh tanks, but this method works on both models, right Roger?

Hi Texwis,

This fuel flow item is a design function of flat tanks. Yes it works on either the SW or LS. The fuel will follow the ball on the bank indicator. If you want fuel to flow to the right wing then make the ball go to the right approximately 1/2-1 ball out depending on how fast you want it to transfer. I fly on long distance trips with my ball 1/2 to the left as that wing drains a little faster.

Originally Posted by TEXWIS

... "Empty" and "airplanes", are two words that dont sound good in the same sentence...

1) you can run out of fuel with fuel on board. as long as you can see fuel in at least 1 site tube the fuel is available to the engine. the danger is in running 1 tank dry and sloshing the other tank outboard due to slipping.

2) you might have no issue other then a slip/skid ball that isn't calibrated or adjusted correctly. you can confirm your ball with your site tubes. find "level" by adjusting rudder or rudder trim early in your flight with equal amounts in each tank and watching your site tubes then see if your ball is centered.

3) high vs. low wing isn't what causes fuel to slosh. think leading or trailing wing. the high wing could be trailing.

4) with 1 empty tank and a crosswind approach and landing you could realize fuel starvation. make sure you can see fuel and if not crab instead of side slip your approach.

I have tried the leading wing/trailing wing method to use fuel from the fuller tank and it never worked for me because the leading wing is allways lower when you step on the rudder with the auto pilot engaged. How can you make the leading wing be the higher wing and stay on course. If left tank shows less fuel as most all of these birds seem to burn from left tank first, then you step on right rudder, the only way to stay on course is to use left aileron which raises the right wing. This is the only method I have found to burn or transfer fuel from fullest tank. I would agree on the leading wing theory if you can accomplish this without making it the lower wing, as I dont think you can make fuel flow up hill.

Was the addition of the slosh tanks on the LS model to help from tipping the fuel away from the suction line in an approach with one empty tank? I noticed one of the early accidents involved an SW running out of fuel on approach into an airport in Tennessee enroute from Florida. It would be hard to beleive he flew all that way and ran out yards short of the runway. More likely it happened as you guys warn not to slosh fuel outboard while banking with an empty tank.

Originally Posted by TEXWIS

I have tried the leading wing/trailing wing method to use fuel from the fuller tank and it never worked for me ...

fuel to the trailing wing is not a method but physics. you are correct that when holding a course that the trailing wing will be the low wing. this does not mean you can't turn changing the low wing to a high wing and still keep the now high wing trailing. just focus on the ball.

example: your left wing drains first so when holding course your left wing will be low. what if you need to make a serires of right turns in the pattern or even a right circling approach? this is where you might need your high wing trailing.

For fuel balance with the autopilot on trim the rudder towards the low wing until the wings are level looking at the horizon. This works for me to keep the fuel level the same on a long trip. Tom