Do you Store with Full Tanks?

[MBDiagMan]

I topped off the tanks before putting her away for a month while on vacation.  Was this the right thing to do?  Will the fuel expand and cause leaks?

Thanks for your comments.

[peevee]

We don't. I remember reading weep no more saying it was best for the seals to keep them full.

[carusoam]

Note how far up hill the wing goes.

Note the position of where the tank vent is.

There is a huge volume of air beyond the vent near the top of the tank.

Not possible to cause a leak.

Really hard to have it over flow the vent.

this all depends on gravity and tank design. If you park on a hill sideways, you can probably get some fuel to pour out the vent.

If for some reason your tank gets pressurized. Use a piece of wire in the vent to see what the cause is.

last thought... heat is bad for tank sealants.  Keeping the tanks full is a good way to keep the sealant from experiencing the heat of the sun,

PP advice, not a mechanic.

Best regards,

-a-

Edited April 26, 2017 by carusoam

[N252WD]

mine stay about 1/2 full, never had a problem. 

[Bennett]

I top both tanks after every flight unless I know I will be having a heavy passenger/s for the next flight.


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[jlunseth]

I read advice opposite to what Paul (Weep-No-More) says several years ago, that is, keep the tanks low to reduce the weight they bear during storage.  Frankly, I don't think it makes any difference.  At any rate, I have always left the tanks low and topped off before flying.  My tanks were sealed by Weep-No-More in 2009 and I have no leaks a thousand hours later, and that includes around 50 landings on grass and many more on small runways and poor asphalt.  I think it is much more important to have an excellent sealing job than how you leave the tanks.

[1964-M20E]

It depends on where I've landed, what time it is, where I'm going next, when I'm going and the price of fuel factors in.

Generally I will top off the tanks when I'm done flying.

 

[Jerry 5TJ]

If the tanks are full or close to full when I'm putting the Ovation away for a while I'll slide the floor jacks into position and take about 1" of compression off the rubber biscuits.  

No idea if it prolongs the biscuit life.  Perhaps.  It does mean I'm more comfortable buying cheaper 100LL and tankering it home.  

 

[Zwaustin]

I leave them pretty full since I am too lazy to fill up day of departure. I like to get home and have them filled for my next trip that way I can hop in and go. A full tank is not hurting your gear or biscuits enough to make it worth leaving them empty.

[Oldguy]

I will typically not fill up on return but go out the evening before my next planned flight to fill up the tanks and do a pre pre-flight check. Since I usually fly with only two people, I always top up and like to land with 1/4 tanks or more.

[PTK]

1 hour ago, Jerry 5TJ said:

If the tanks are full or close to full when I'm putting the Ovation away for a while I'll slide the floor jacks into position and take about 1" of compression off the rubber biscuits.  

No idea if it prolongs the biscuit life.  Perhaps.  It does mean I'm more comfortable buying cheaper 100LL and tankering it home.  

 

That's a very good idea. And I've been thinking about doing so as well after I change biscuits at next annual. Which jacks do you use? Is there a type that can be locked in place so it doesn't drop on it's own?

[kevinw]

I was told once never to top off completely to the rim because the fuel will expand with temperature and possibly start a leak. For this reason I fill to 1-2" below the rim unless I'm departing immediately. Not sure if there's any truth to this but owning a '82 that's never had the tanks resealed I'm taking every precaution while on borrowed time.

[Bob - S50]

We've had our plane for 4 years now.  It's a '78 and has never been re-sealed.  No leaks.  We fill it to 30 - 35 gallons (out of 64) before putting it away for the day.

Just for a third "I read it on the internet so it must be true", I heard that it was the fumes that kept the sealant from drying out.

[gsxrpilot]

17 minutes ago, kevinw said:

I was told once never to top off completely to the rim because the fuel will expand with temperature and possibly start a leak. 

No truth to that what so ever.

I keep the tanks full for convenience. There's been no credible reason or argument to the contrary.

[DonMuncy]

2 hours ago, Jerry 5TJ said:

If the tanks are full or close to full when I'm putting the Ovation away for a while I'll slide the floor jacks into position and take about 1" of compression off the rubber biscuits.  

No idea if it prolongs the biscuit life.  Perhaps.  It does mean I'm more comfortable buying cheaper 100LL and tankering it home.  

 

I think this is a good idea. However, my plane looks like it is on life support as it is. It has plugs in all its openings, a plug-in for the Battery Minder and a hose and vent for its engine dryer. If I add a few more things, I will be taking more time to get the plane ready to fly, than I do flying  

[RobertGary1]

The only downside is that when you want to fly you're tanker a bunch of heavy gas. Like buying a Lambo and pulling a boat behind it. A Mooney with full fuel is useful for super long trips but oh so doggish.

 

-Robert

[RobertGary1]

1 hour ago, gsxrpilot said:

No truth to that what so ever.

I keep the tanks full for convenience. There's been no credible reason or argument to the contrary.

Its a Cessna issue. I've seen Cessnas dripping fuel out the vent on hot days in the sun.

-Robert

[gsxrpilot]

Its a Cessna issue. I've seen Cessnas dripping fuel out the vent on hot days in the sun.
-Robert

Exactly. Fuel can expand but will vent, will not cause tank to develop a leak.

[MBDiagMan]

Thanks for the great responses guys!

I have been in a hangar shuffle with the Mooney at an airport with $3.20 gas, so I began topping it off before putting away.  I feel better now for leaving her full and setting for a month.

[peevee]

1 hour ago, MBDiagMan said:

Thanks for the great responses guys!

I have been in a hangar shuffle with the Mooney at an airport with $3.20 gas, so I began topping it off before putting away.  I feel better now for leaving her full and setting for a month.

At 3.20 I'd show up with a pickup and a big tank on wheels lol

[Rmag]

For what its worth Henry Weber's Aircraft recommended that I not completely fill the tanks and park it.  Said it puts more weight sitting on the gear and he felt that a full tank of fuel is always "looking for a way out".

[EricJ]

I seem to recall that one argument for keeping the tanks full is that condensation can't form on the inside of the tanks if it's full.

[Nokomis449]

Just to be safe, I'd split the difference and store with one tank full and the other tank empty.  

[Rustler]

 

10 hours ago, 1964-M20E said:

It depends on where I've landed, what time it is, where I'm going next, when I'm going and the price of fuel factors in.

Generally I will top off the tanks when I'm done flying.

 

+1.

It is also easier when beginning a day's flying not to have to go from the hangar to the fuel pump, shut down, fill, then continue.

 

 

[flight2000]

3 hours ago, Rmag said:

For what its worth Henry Weber's Aircraft recommended that I not completely fill the tanks and park it.  Said it puts more weight sitting on the gear and he felt that a full tank of fuel is always "looking for a way out".

So if you leave say 5 gallons out of each wing, you're saving a whooping 60 pounds of weight on the gear.  That advice from a shop makes no sense at all to me.  Any liquid in general is looking for a way to escape its container - full or half full really doesn't matter IMHO.

I always parked mine full so I didn't have to worry about taxiing over to the fuel pumps before a flight.  Prefer any water that happens to get into the fuel tank to have settled to the bottom overnight or while waiting for the next flight.  I also subscribe to the theory that a wet seal is a happy seal and is less prone to dry out and fail.   Just my .01 cent worth...

Cheers,

Brian