Bladder or wet wing

[67 m20F chump]

I have been cleaning sealant out of my wing for what feels like a lifetime.  I’m getting close to having it all cleaned out.  While working on this I start thinking maybe the Griggs O&N bladder stc was a better way for fuel storage.

 

 I have looked over the instillation instructions and been thinking about the 4 tank per wing solution that retains 64 gallon capacity.  I see this has only one fuel sump shared between 4 tanks.  The Baron I had used one sump per fuel cell. 
 

Any of you guys running this stc have concerns about this setup?  I feel like bladders have less of a chance of leaking but this has me rethinking it.

[KSMooniac]

Check out how much the 64 gallon kit weighs before you make your decision too. I'm a fan of useful load and would never "pay" that much weight for bladders, but others happily do, YMMV, etc. If your tanks are clean now, I'd say you're over the hump and should just go ahead and reseal.

Sent from my LM-V405 using Tapatalk

[carusoam]

There are plenty of pages of install notes and pics and decisions…

Bob, Terry, or Marauder might be able to point you towards the thread…

Old sealant gives new sealant a bad name… 

-a-

[67 m20F chump]

I fly off grass all the time and thought that was hard on sealant.  The weight hit is 36#.  I pulled out the vacuum system and did a avionics upgrade.  My useful load will be about 1000# still.

[BDPetersen]

There is one sump in each wing. So two bladders per sump in the 4 bag system. I am pleased with mine but I am never useful load challenged.

[A64Pilot]

Even with a sump per bladder, any bladder can trap water. The C-210 we had, apparently had a wrinkle on the bottom of the bladder and a leaking left fuel tank cap. you could sump the fuel and get no water, rock the wings and get water.

Having said that my Mooney has bladders and I like them, glad it does.

‘I’m not so sure grass is bad on a wet wing airplane, the reason is that there are two Ag plane manufacturers, both have wet wings, and Ag planes usually fly off of rough strips day in and day out and can land several times an hour over and over, and the wet wings don’t leak usually until they get old, so I believe it’s more of a age thing.

Bladders have a life limit too and leak when they get old, but they are usually a lot easier to remove and have repaired, and the repairs have a very good track record.

Bladders in Mooney’s  I assume just aren’t old enough yet to start leaking, but they will, wait and see.

[Marauder]

13 hours ago, 67 m20F chump said:

I have been cleaning sealant out of my wing for what feels like a lifetime.  I’m getting close to having it all cleaned out.  While working on this I start thinking maybe the Griggs O&N bladder stc was a better way for fuel storage.

 

 I have looked over the instillation instructions and been thinking about the 4 tank per wing solution that retains 64 gallon capacity.  I see this has only one fuel sump shared between 4 tanks.  The Baron I had used one sump per fuel cell. 
 

Any of you guys running this stc have concerns about this setup?  I feel like bladders have less of a chance of leaking but this has me rethinking it.

I am a long time owner of bladders. In fact, when I was going through the pre-buy with my Mooney in 1991, both of my tanks had leaks and another interesting phenomenon. Both tanks had these long rubber like worms in it. I found out later that this was a sealant coating added over the original sealant to protect it from the 100LL. This sealant broke down and formed the worms. It was pretty disconcerting to see some of these worms around the sump drains. 

When I looked at the options at that time, $5k for bladders or $5k for a complete reseal, I opted for the bladders. Aside the AD that came out in the mid 2000s, the bladders have been rock solid. Even now, if I had to replace some bladders, the 30 years I got out of them certainly was worth it.

For the folks that talk about loss of useful load. Yeah, you lose some. But when I was 290 pounds and went to 210, I gained 80 pounds of useful load. Far exceeding any weight penalty of the bladders. 

As for the water concern, I have yet to see any water in the years I have flown with the bladders. I have drained the tanks completely several times to add CiES senders and to replace sump drains. I do think it is important to make sure the filler caps seals are in decent shape. The original filler caps had seals that lasted for years but when I went to replace them, I couldn't find the O rings. The new caps have easily replaced seals.

[pirate]

I had my bladders installed in 2005, paid $10,700 then. Probably could save a lot of money installing your self with a IA friend.
I have not had any problems since, sure don’t miss the constant sealing / patching  and fuel odors. 
Over the years I’ve changed over to the light weight starter, alternator, got rid of the heavy gyros, radios and vac system so use full load is a non issue for me. 

[RobertGary1]

On 6/21/2021 at 12:28 PM, pirate said:

I had my bladders installed in 2005, paid $10,700 then. Probably could save a lot of money installing your self with a IA friend.
I have not had any problems since, sure don’t miss the constant sealing / patching  and fuel odors. 
Over the years I’ve changed over to the light weight starter, alternator, got rid of the heavy gyros, radios and vac system so use full load is a non issue for me. 

For that money you could have had a pro seal the tanks and similarly have been leak free without any constant sealing and patching. 

[67 m20F chump]

I went with the bladders.  I’m coming from Beechcraft and I’m used to them.  I have been into the wet wing 2x now and if I never do it again that will be fine with me.  Bladders are just easier to deal with.  I’m taking the weight hit for them.