C172 G1000 and C152 - left fuel tank drains faster - intermittent

Moderators - I place this here in ‘Discussion’ to see if anyone else has noticed this issue. Its intermittent and so reporting it as a bug would be pointless I think.

The problem is simply that sometimes the left tank drains faster than the right and Im a pilot that makes mostly left turns or flies level.

I had thought maybe it was something I was doing with the fuel tank selection switch in the C172 but the C152 has no switch. I thought maybe it was caused by gravity feeding but with my tendency to makes mostly left turns, one would think the right tank would empty faster. To confuse the issue further, its an intermittent problem. It happens maybe 50% of the time.

There has always (pre beta) been something not right with the C152 concerning balance – its as if ‘left’ and ‘right’ are mixed up – but now it seems the C172G1000 has ‘caught’ some of these balance issues.
Note: I always fly the default livery C152. I fly several different liveries for the C172G1000 standard passenger. I hope it doesnt matter.

There are a number of topics related to fuel issues with the Cessna 172 & 152.
Have a look at the results of this search:
Search results for ‘fuel tags:cessna-172-skyhawk,cessna-152 in:title’

Some of the results are obviously not relevant, but some might be applicable to your situation & settings.

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The 172 and 152 do this in real life.

The fuel tank vent is on the left wing, and it gets a little bit of ram air pressure during cruise flight, thus causing that tank to tend to drain faster in level flight as there is an air pressure imbalance vs the other side. It’s slight, but it is real.

On long flights, occasionally setting the selector to the right tank only for a little time will correct it.

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Thank you for that information. I’ll just have to learn to live with it then. Its amazing they detailed the simulation to that degree!

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In flights of an hour or so it doesn’t really matter, but it adds up a bit over multiple hours. It is pretty much never enough to really matter for balance, so doesn’t really require much attention.

The tanks have a vent pipe that links them together over the top of the cockpit, but the left one is where that vent inlet is. It’s basically the same system in many small planes, but since Cessna has that ‘both’ position, it becomes noticible. Most other planes just have a L or R selector, so it can only draw from the selected tank, this makes that pressure imbalance irrelevant in most cases.

I have been flying the C152 for a while now and this is what I see:

Due to the fact that the airplanes constantly banks right UNLESS I add four more gallons to the left tank than the right, that is what I do. So… the default C152 starts with 6 gal in each tank and I use the EFB to add 4 to the left tank.

I take off and fly and over time it starts banking right again and I use the EFB to check fuel and it shows again and again that the right tank doesnt drain until the left tank gets down to that same quantity. Maybe this is how it is in a real C152 but it doesnt sound logical because if the tanks are directly connected then the right tank should actually fill slowly FROM the left. Somethings not right here.
This is why I thought the C152 left tank drained faster.

Not sure why you are seeing a permanent bank in a specific direction. Have you checked your turn & bank to see if you do not have some rudder in the opposite direction?

Does your C152 not have a slight roll to the right tendency? Its not major - just a slight roll. Whats weird is that the C172 has a slight left roll tendency and so I haven’t bothered to check my controls – but I guess I should. The weight and balance section of the 152 doesn’t seem finished by any means so I think thats part of it.

I just don’t know why the left fuel tank would have to drain down to the right tank level before fuel started coming out of the right tank. I’m not a real pilot so maybe thats just how it is IRL?

Hhmmm, I should have done a bit of checking before commenting on what I do not know! I really have not flown the 152 virtually at all, and when I did fly it I cannot recall doing much hands off flying. Ergo, I know nothing about its foibles. Let that be a lesson to me…

Yes, indeed, I took it up and it does tend to the right repeatably. In real life I would have said it was a touch imperfectly rigged in terms of (the fixed) rudder and/or aileron trim tabs. So IRL, if this was something that bugged you, you could get it tweaked to “straighten up and fly right”. Alas, that is not an option in the sim. Quite the last time I flew a real C152 or 172 was like 40 years ago, so I truly cannot recall if the aircraft I flew had similar tendencies.

So my apologies: my comment was really only pertinent to aircraft in the sim flying with the AP on. In that case, any slight persistent rudder input leads to the AP adding opposite aileron to fly straight, if not level. :slightly_smiling_face:

Moved out from Sim Update 3 Beta | MSFS 2024 > SU3 Beta Discussion since not a SU3 related discussion.

Thank you :slight_smile: Now I know its not just me. I think if it had the weight and balance section finished then it might be curable in other ways but I also agree with how great it would be if the sim had a ‘garage’ where you could bend some trim tabs when needed. Thanks again.

Still leaves the fuel thing a mystery though.