Fuel Balance

[zzfriend]

The digital fuel flow is spot on for fuel usage, but when I refuel the
airplane (A-1B on amphibs), it'll take up to 10 gallons more in the
right tank than the left. I don't think I'm skidding the airplane
quite that much in level flight.

A) What am I doing wrong?

B) If one tank runs dry, will it draw air into the system and shut
the engine down?

Thanks for your help on this, hope I'm not asking old questions. Glad to see the new forum!

 

[Jim Taylor]

You might check to make sure both wingtip fuel vents are clear and check your wings inflight to see that they are both equally above the horizon T&B's can be installed crooked- the big horizontal tube at the top of the windshield is the reference for wings level and if that's level the ball should be centered.

No worries on getting air into the system if one tank runs dry. Fuel will flow out of whichever tank has more gas in it.

 

[lowlevelops]

zz,

If the aircraft is not sitting level when parked, the fuel in the tanks will level out putting more fuel in one tank.

 

[PapaZulu]

Faulty fuel cap gasket

ZZ:
I had small bits of excess gasket rubber that prevented a positive seal in one of my fuel caps. Remove the rubber seal and inspect for debris.

Frank

 

[zzfriend]

Hangar floor's level. I'll check the vents and caps, and not worry about one tank going dry. Thanks much!

 

[Kinoav8r]

ZZ,

What Trace is saying is as you fill the first tank, fuel flows into the other tank. There is no check valve to prevent this and the fuel shutoff valve is down stream of the "y" fitting that joins the two tanks. Look in the tail above the battery and you'll see the lines coming together from the left and right tanks.

If you've got an extended baggage mod, you might have to have x-ray vision...

 

[Splashlanding]

I have one bushwheel that looses air from time to time, that will make them start off wrong.

Ki

 

[Jerry Cain]

Bushwheel Air Loss

As I understand it, the Bushwheels will all lose a small amount of air over time due to the rubber compound they are made from. I suspose some may lose a little more than others. Therefore, check your air pressures periodically.

 

[Kinoav8r]

As I understand it, the Bushwheels will all lose a small amount of air over time due to the rubber compound they are made from. I suspose some may lose a little more than others. Therefore, check your air pressures periodically.

Look for TomD's new mod that will fix the air imbalance. It will also be called the "NMP (No More Pisssst) valve".

 

[nlbunger]

fuel tanks not feeding the same

In addition to flying a husky I also fly and am the mechanic for a Aerial Applicator. We had one of our planes that was using more gas out of the right tank than the left. On those airplanes there is a drain for the fuel vent system and long story short, the vent was full of gas. I don't know if the husky has a tand vent drain, but maybe worth checking out.

 

[Snowbirdxx]

The Husky is only vented by the two ventlines that exit near the wingtip. Early Huskys had the fuelvent outboard of the tank below the wing.

Some operators use in addition to that ventes fuelcaps.

The vent lines have a checkvalve each that should prevent overflow and which should allow fuel expansion.
This checkvalve may not always operate the way it should and will let fuel run out.

The ventline often becomes home of insects that build nests in there. Thts the end of the venting & fuel flow then.

The new NMP valves are an addition to help the fuel stay in the tanks and they keep the insects out. If no NMP is used on one tank at least one tankvent should be protected by a screen of you need to make sure the vents are open . This is best done by carrying 2 ft of instrument hose. On preflight stick it on the vent and blow in the tube. There should be no restriction.

But as said, small finger type screen from a motorcycle fuel cock permanently over the ventline, keeps the bugs out.

TomD

 

[aksam58]

A partially blocked vent tube could be very likely, if it's always the same side that takes more, and you're fueling right after flight (before the tanks have time to equilibrate.

The screens sound like a good idea as bug-stoppers.

A problem we've seen in Alaska has been water droplets which have formed and then frozen in the long, narrow vent tubes; if both sides block, no more fuel flow. We've had at least one dead-stick landing, one Husky that quit on taxi, and one that wouldn't start up and stay running due to ice in the fuel vents in the last few years in Alaska that I'm aware of. (The dead-stick landing was after more than an hour of flight!)

I'm sure this isn't the problem in the thread in general. One word though, about vented fuel caps as extra insurance against losing gravity feed from both tanks....it DOES require FAA approval, believe it or not, to switch to vented caps. Not a big deal; mine was done as a DER approval.

 

[Splashlanding]

Wow Sara, You should almost start a new thread.
Those are some problems we have not seen in the lower 48. Thanks for sharing them.
I have not seen anything in the forums about those kind of issues until now.


Ki

in Florida