Uneven fuel tank levels

[foxdog]

Hi Guys,
I need some help with a Jab J170 that holds 135l of fuel.
The problem seems to be rescent in that after 2 hrs of flying the fuelsightglass indicates 75% left tank and25% right tank.
After standing on the ground for some time they eventually level out.
Does this mean that the left tank could be partially blocked and would this cause total fuel starvation if one flew the right tank empty.
Regards,
Foxdog

[heisan]

Generally, it means that your feat are lazy

[happyskipper]

Generally, it means that your feat are lazy

Interesting feat that -

Would the ball being out to the left or the right cause this?

[Flooi]

Generally, it means that your feat are lazy

Ja, nogal quite a feat to use your feet. Hou die bal in die middel
On a serious note: whilst in flight, it is possible to equalise the tanks by opposite rudder.
I doubt that you will have fuel starvation...... but the right man to comment is ZuluBen
on this forum.

[scsirob]

If by any chance your feat are working well and the ball is in the middle, check the fuel vents.

[foxdog]

Hi Scsirob,
I will start by looking at the vents.
Are there perhaps any seperate finger or in line filters that you know of that perhaps i should look at.
Regards Foxdog

[scsirob]

Are there perhaps any seperate finger or in line filters that you know of that perhaps i should look at.
Regards Foxdog

I'm afraid not, I do not own a J170 (or a Jabi plane for that matter).

[ZuluBen]

Afraid to say the guys are correct, the ball is not centered during flight.

Oom Jim tough me: "The fuel will follow the ball"

Had many Jab pilots call me to say that they had to do a precautionary because the red light came on but they still had 50l ...

Oh, and do your self a favour, reset your fuel flow to read 120l usaable from full tank. Trust me.

[Shaunus]

I now set mine to 125L after having the same happen to me!

Ben is it fair to assume that when the fuel light becomes steady, you have:
6.5L remaining in the header = 15min MAX = 25nm MAX?

Also, what ball park figure of fuel remaining to you assume you have when you first start seeing the intermediate flashing red light? (on my aerie, this starts to happen when the fuel inspection tubes show around 1/4 to 1/5 left in each) - I have only seen the red light flash twice. And only once have I seen it go to steady on, which freaked me out for obvious reasons as am generally a stickler for the 45min reserve! I think it was around 10min from first flash to steady on, but I can't seem to remember for sure.

(this is all assuming that you drain the last bit evenly by adjusting the ball)

Thanks for your knowledge as per usual
Shaun

[Swampdonkey]

Hi Guys, With all due respect to the previous posters, I think it's more than just a "ball in the middle" thing, I flew back from Carnarvon to FASH some time ago, and I had the same problem. Try as I might, I could not get the fuller tank to feed. I finally landed with zero in the one tank, the red light on for about 5 minutes, and about 20 litres in the other tank. I tried flying cross controlled , I tried sideslipping, I even tried shutting off the empty tank at the fuel stop, I tried everything. nothing worked.

After landing I got out and rocked the plane vigorously from the wing tip, and suddenly the fuel started to equalize. I think it's got to do with vents.

[foxdog]

Hi Gents
Thanks for replying I have cleaned the vents and will be doing 2 two hour legs on Sunday and will concentrate on the footwork and let you know
Regards
Foxdog

[happyskipper]

Hi Guys, With all due respect to the previous posters, I think it's more than just a "ball in the middle" thing, I flew back from Carnarvon to FASH some time ago, and I had the same problem. Try as I might, I could not get the fuller tank to feed. I finally landed with zero in the one tank, the red light on for about 5 minutes, and about 20 litres in the other tank. I tried flying cross controlled , I tried sideslipping, I even tried shutting off the empty tank at the fuel stop, I tried everything. nothing worked.

After landing I got out and rocked the plane vigorously from the wing tip, and suddenly the fuel started to equalize. I think it's got to do with vents.

Yes.

[pafuri]

So how do you clean the vents ?

[ZuluBen]

Ben is it fair to assume that when the fuel light becomes steady, you have:
6.5L remaining in the header = 15min MAX = 25nm MAX?

I have shoulder taps in my plane. So i parked the plane in flying attitude, removed the fuel pipe just before the carb, closed the shoulder taps so that we can only feed from the Header tank.

The light started to flicker almost immediately, and after it came on steady, I got another 5l out of it. So at 20l/h that means 15min to donkey stop. Realistically at this point you would reduce speed to 80 kts to sip about 13l/h, but I have set myself 10 min plus a few minutes of "fudge time"

Clean the vents on the caps with a piece of stainless wirelock after disassembling them. Easy and quick. If you pick up problems there, get a set of those little red cover to pull over the vents when parked.

Let us know

[Flooi]

Anything new on this?