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Tank seal vs Bladder


wcb

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I have seen a ton of people happy with both.  I have searched to find anything related to any additional safety that bladders may or may not provide.  It would seem logical that bladders may provide additional safety in a gear up situation (fire ignition from sparks etc), does anyone have any articles, info or opinions (I know there will be a few of those ... :) )

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There is virtually no risk of fire in a typical on-airfield gear up in your Mooney.

The whole reseal / bladder argument involves more money for bladder conversion, sometimes cutting new gas cap panels and plugging the old (and painting to match), and a whole lot of emotional involvement. It is one of the most contentious topics here, as a quick Search will reveal.

I did a strip and reseal in 2011 for 40% less than a bladder conversion would have cost, with zero cosmetic affects.

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I certainly have seen many of the threads and emotion that surrounds it.  I have been on the schedule to do a reseal but they have been back logged (weight and cost was part of my original decision to go reseal).  Due to the challenges of scheduling I thought I would revisit the decision to reseal and the safety issue came to mind.  I see there are almost never any fires associated with a gear up with the exception of a few off field gear ups that have happens on streets or highways where the wing has then clipped something to trigger a fire.

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16 minutes ago, wcb said:

I certainly have seen many of the threads and emotion that surrounds it.  I have been on the schedule to do a reseal but they have been back logged (weight and cost was part of my original decision to go reseal).  Due to the challenges of scheduling I thought I would revisit the decision to reseal and the safety issue came to mind.  I see there are almost never any fires associated with a gear up with the exception of a few off field gear ups that have happens on streets or highways where the wing has then clipped something to trigger a fire.

I'm not sure why this is an emotional topic. Some like vanilla ice cream, others chocolate. Both get the job done. I think you should look at the values/differences of both approaches and make the decision based on your assessment of what meets your need. I'm happy as an owner who has 27 year old bladders. They owe me nothing...

As for the fuel leakage in an accident. It comes down to basic physics. If the accident momentum is high enough, nothing is going to keep fuel in the wings. 

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I think the main reason to get the bladders is for resale.  When I purchased my aircraft the bladders were 20 years old.  However, they can be refurbished in situ for very little money, which gave me quite a bit of confidence that I wouldn't have had with a 20 year old reseal.  If you plan to keep your Mooney for awhile I'd do the bladders.  And what he said, go for the 64.

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All modern airliners have integral tanks. The reasons:

Only cans of sealant need to be in stock at the MROs for tank repairs. With bladders you need to have in stock the bladders for each wing section for each plane model.

Bladders weight is considerable more vs integral tanks, thus reducing payload capacity.

Moisture trapped between the bladder material and airframe structure can cause corrosion. 

José

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40 minutes ago, Piloto said:

Moisture trapped between the bladder material and airframe structure can cause corrosion.

Can you provide any evidence that this is anything but a bladder-hater claim?

In the two cases I am aware of, it was not a bladder issue, it was a paint stripper issue which somehow got blamed on the (innocent) bladders.

Since my bladders are approaching 30 years of leak-free, trouble-free service, I am very interested in your claim.

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7 hours ago, Marauder said:

I'm not sure why this is an emotional topic. Some like vanilla ice cream, others chocolate. Both get the job done. I think you should look at the values/differences of both approaches and make the decision based on your assessment of what meets your need. I'm happy as an owner who has 27 year old bladders. They owe me nothing...

As for the fuel leakage in an accident. It comes down to basic physics. If the accident momentum is high enough, nothing is going to keep fuel in the wings. 

That’s certainly the truth: Mooney fuel bladders aren’t self-sealing battle damage resistant internal tanks.  They are plastic bags that hold fuel.  A great way to keep said fuel in the wings, I might add!

its only emotional because some personalities can’t accept that two different methods could be subjectively evaluated both equal or unequal for certain missions, despite set objective differences.  Garmin vs Avidyne (or garmin vs aspen), bladders vs reseal, single vs twin, crab&kick vs. forward slip, turbo vs NA.....it’s funny to me, too, what gets some people worked up!

One of the guys I instruct with likes to say the following in his briefs... 

“There are lots of techniques.... but mine are superior.”  Of note, I don’t believe his techniques are superior. ;)

 

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4 hours ago, Mooneymite said:

Can you provide any evidence that this is anything but a bladder-hater claim?

In the two cases I am aware of, it was not a bladder issue, it was a paint stripper issue which somehow got blamed on the (innocent) bladders.

Since my bladders are approaching 30 years of leak-free, trouble-free service, I am very interested in your claim.

Not a bad idea to remove the bladders after 30 years and check for corrosion at the next annual. 

José

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GET OUT! Again?

Here's what was posted on the Mustang board recently:

On Jun 2, 2018, at 8:48 AM, Mani Agokm [mustangaero] <mustangaero@yahoogroups.com> wrote:
 
Yeah, but as I understand it, mooneys have bags, and thats a different animal.
That other ships with prosealed tanks are having leaks/weeps is new to me.  But I've not owned before so dont really know.
Arent Cessna and Piper tanks prosealed as well?  Dont much remember them leaking  if ever.           
My Reply:  Mooneys can have bags (bladders). They are an aftermarket item, no production Mooney was fitted with them to my knowledge. That said, if you want some fun, go over on Mooneyspace and post “Bladders are better than a reseal.”

 

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1 minute ago, Piloto said:

Not a bad idea to remove the bladders after 30 years and check for corrosion at the next annual. 

José

José, sounds like a pretty bad (somewhat expensive) idea to me.  I think I'll wait for the AD. Or a "mandatory" SB. Or a few actual cases where corrosion was found. 

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Both...

Bladders are good.

Modern Integral tanks are good.

 

The only thing that will keep a fire from erupting is to not mention that either one of these great Mooney fuel systems is better than the other... :)

It is possible that one is better than the other... but, that would take knowledge of the person making the decision...

As in... which is better for me?

So WCB, which is better for you?

I went with the Piloto method... 100+ gallons of fuel in integral tanks... and it has made all the difference.... 

One of these days... i’m Going to add those fancy digital floats and a fancy digital monitor and a fancy waas gps to fully integrate with those integral tanks...

PP thoughts only, not a mechanic...

Best rgeards,

-a-

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Here is a similar discussion of bladders vs wet-wing. Cessna no longer uses bladder tanks.
https://www.pilotsofamerica.com/community/threads/fuel-bladders-vs-wet-wing.67047/
José
 
 
 
 
 
 


There was nothing in that thread that said “buyer beware”, this plane has bladders. It actually says the opposite — Cessna owners who say don’t be afraid of the bladders.

Another thing to remember is these bladders are installed in the plane without removing the original sealant.


Sent from my iPhone using Tapatalk Pro
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As I suspected this topic has brought up all the usual arguments for and against bladders with not much info on perceived or real safety.  As I stated  I had already made my decision and with the simple back log at the shop has given me to rethink the safety issue. 

@carusoam I have the fancy CIES sending units ready to be installed and the JPI EDM 900 recently installed.  I will provide a PIREP when after the tank work and sending units are complete.

However, to add a little fuel to the fire what if the bladder added no additional weight, cost the exact same as a reseal, resale value add-on was the same, and corrosion issues were the same?

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As I suspected this topic has brought up all the usual arguments for and against bladders with not much info on perceived or real safety.  As I stated  I had already made my decision and with the simple back log at the shop has given me to rethink the safety issue. 

[mention=7104]carusoam[/mention] I have the fancy CIES sending units ready to be installed and the JPI EDM 900 recently installed.  I will provide a PIREP when after the tank work and sending units are complete.

However, to add a little fuel to the fire what if the bladder added no additional weight, cost the exact same as a reseal, resale value add-on was the same, and corrosion issues were the same?

You'll get the same answers. You need to remember most of us are crotchety old men who are set in our ways. Give any of us a beautiful blonde and some would complain she wasn't a red head. Both fuel tank approaches are fine. I love the comments about the weight penalty. 29 pounds of extra weight is nothing when you realize some Mooney pilots are 50 pounds overweight. I do agree with the comment about getting the 64 gallons version of the bladders if you plan on flying long legs.

You will love the CiES senders. When these senders were introduced by Scott and the CiES folk, I was one of their toughest critics. Not that the technology didn't make sense, rather Scott, while a great engineer, is a lousy sales guy. And after working through some intercompany technical issues, I was able to get them calibrated in frequency mode. Since I installed them, they have spot on. And I mean literally within a few tenths of a gallon on fill-ups. Never have I flown my plane with that level of confidence in the fuel gauges.

 

Edited by Marauder
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I haven’t seen any data that would make one system stand out as being safer over another...

We don’t have any crash testing like the large market automotive companies.

I haven’t seen the FAA break down the detail of tank failures for Mooneys.  I have seen the small helicopters go through the effort to improve fuel tank impact safety...

I wouldn’t expect the current fuel bladder systems to be naturally safer in an impact because they weren’t designed for impact integrity. There are a few connectors that need attention in the next version...

There is a possible method of gathering existing data to try to find some clues... but there aren’t that many accidents where statistically valid data can be used... know anything about big data?

There is a thread around here that helps people sift through all the FAA crash reports looking for specific things... I spent some time researching all Ovation accidents...

One thing that would help... if there is a fire on the copilot side... it would be nice to be able to exit the pilot side door....

WCB, you have a great question, With no strong answer...  the training for off Airport landings can be hard to follow.

Some Mooney owners have installed seat belt airbags to improve their statistics.

PP thoughts only, not a CFI or mechanic... these comments are intended to spark some ideas that may get somebody to come up with or share some ideas... It is not intended to douse the creative fire that somebody may have...

Best regards,

-a-

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On 6/4/2018 at 6:02 PM, Mooneymite said:

Can you provide any evidence that this is anything but a bladder-hater claim?

In the two cases I am aware of, it was not a bladder issue, it was a paint stripper issue which somehow got blamed on the (innocent) bladders.

Since my bladders are approaching 30 years of leak-free, trouble-free service, I am very interested in your claim.

Gus-Here is an example of how bladders can trap moisture and thus cause corrosion...and this is coming from a Mooney guy who put bladders in his airplane (me). This was a twin otter I used to maintain, we had to re-skin the entire belly of the airplane. There are 8 bladders in different sections-not an M20 but the concept is identical. I have heard of other DHC-6 with similiar issues as well. Like I said, I am a Mooney Bladder Fan, but what Jose is saying has some truth to it...

 

DHC6-1.jpg

DHC6-2.jpg

DHC6-3.jpg

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On 6/4/2018 at 1:21 PM, 1964-M20E said:

if you go bladders definitely get the 64 gallon version.  I have the 54 gallon version and would like to have the extra 10 gallons on a few of my flights.

Definately. It is the difference between a 750nm airplane and and 900nm one.  Need an IfR alternate then subtract 100nm from each 

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On 6/4/2018 at 10:40 PM, Piloto said:

Not a bad idea to remove the bladders after 30 years and check for corrosion at the next annual. 

José

They are installed in the wings cavities that were formerly full of fuel, sealed and coated with the red Buna-n rubber. I don’t see how water trapped in there can harm the airframe since it’s sealed anyway. 

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3 hours ago, N6758N said:

Gus-Here is an example of how bladders can trap moisture and thus cause corrosion...and this is coming from a Mooney guy who put bladders in his airplane (me). This was a twin otter I used to maintain, we had to re-skin the entire belly of the airplane. There are 8 bladders in different sections-not an M20 but the concept is identical. I have heard of other DHC-6 with similiar issues as well. Like I said, I am a Mooney Bladder Fan, but what Jose is saying has some truth to it...

 

DHC6-1.jpg

DHC6-2.jpg

DHC6-3.jpg

That looks like a lot of corrosion between the fuselage frames and on the longerons but what do bladders have to do with this? 

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