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Mooney Bladder Install


N6758N

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On 10/3/2017 at 10:55 AM, Marauder said:

It is significant and troubling since I had been flying for years with the assumption I had 54.7 gallons of usable fuel on board. I would never cut it that close (my 50 gallons actual versus the 54.7 claimed) but knowing what is really there was sobering. 

Yes indeed, but I've always been skeptical that the 54.8 was fiction and I assume 52.

I flew MRN-6B6 today. 4.7 hours, mostly at 8.2 GPH LOP. Over 600 nm as routed by ATC. JPI totaled 40.7 gallons, I only could add 39.9 on Minuteman's sloped ramp. Massachusetts was severe clear today so burning 40 gallons was okay. But I would have been much more comfortable with another 10 gallons on board. I do love my little E: 145 ktas on 8.2 GPH - ~60%. 

(I had not been in to Minuteman since my prop strike. Their new pave 2700' strip is a huge improvement. I use a little over half of it with the CYA AoA chirping on short final.

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10 hours ago, Bob_Belville said:

Yes indeed, but I've always been skeptical that the 54.8 was fiction and I assume 52.

I flew MRN-6B6 today. 4.7 hours, mostly at 8.2 GPH LOP. Over 600 nm as routed by ATC. JPI totaled 40.7 gallons, I only could add 39.9 on Minuteman's sloped ramp. Massachusetts was severe clear today so burning 40 gallons was okay. But I would have been much more comfortable with another 10 gallons on board. I do love my little E: 145 ktas on 8.2 GPH - ~60%. 

(I had not been in to Minuteman since my prop strike. Their new pave 2700' strip is a huge improvement. I use a little over half of it with the CYA AoA chirping on short final.

One thing I noticed after the plane sat for a while was that I could have stuffed several more gallons in it, and that was in the normal nose high position. I think the 54.8 may be obtainable if you fill the plane up and wait 24-48 hrs and then go back and put more fuel in. Obviously this is not practical nor safe since you can'y always rely on that fuel being there. Since my bladders are freshly installed I am hoping there are some spaces inside the cells that haven't expanded yet, and after some time I will be able to reliably get more fuel in it on a regular basis. 

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14 minutes ago, bluehighwayflyer said:

Yes. This is definitely true. Even though they were already topped off I can usually get another couple gallons in both of our 64 gallon bladder systems (C and J) immediately before flight. 

OTOH, if you do top off to the very top with cold 100LL you will port fuel out the vent tube as the wing warms up. 

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7 minutes ago, bluehighwayflyer said:

I am not aware of having ever experienced that but it is certainly theoretically possible.  I think that the vents are high enough in the tanks to handle the expansion, but Terry would probably know. 

A Mooney certainly will port overboard. BTDTHTTS

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Just now, Bob_Belville said:

BTDTHTTS

? That's a new one for me Bob. Even as a 'young' person I can't keep up on all these darn acronyms! My bladders pushed some out of the vents after I filled them up for the first time so it can definitely happen, albeit less likely than the Cessnas. 

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Just now, mike_elliott said:

Sure its not a bladder leaking Bob? :) 

Ha! My bladders were originally installed in 93 and have sat folded up in a box for the last 5+years. If they don't leak I think its going to be hard to find some that do. O&N Bladders are 2x as thick as anything I've ever seen an OEM put in. 

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Just now, N6758N said:

? That's a new one for me Bob. Even as a 'young' person I can't keep up on all these darn acronyms! My bladders pushed some out of the vents after I filled them up for the first time so it can definitely happen, albeit less likely than the Cessnas. 

Terry, been there, done that, have the tee shirt. Geeze.

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3 minutes ago, N6758N said:

Ha! My bladders were originally installed in 93 and have sat folded up in a box for the last 5+years. If they don't leak I think its going to be hard to find some that do. O&N Bladders are 2x as thick as anything I've ever seen an OEM put in. 

Mike's just a jealous troll shilling those miraculous, lifetime, super duper reseals. :rolleyes:

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Just now, Bob_Belville said:

Mike's just a troll shilling those miraculous, lifetime, super duper reseals. :rolleyes:

I wanted to reseal my tanks, but since I don't use flaps on takeoff and fly ROP, it just was not an option for me. :P

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57 minutes ago, Bob_Belville said:

OTOH, if you do top off to the very top with cold 100LL you will port fuel out the vent tube as the wing warms up. 

 

43 minutes ago, mike_elliott said:

Sure its not a bladder leaking Bob? :) 

I’ve seen this as well. Terry - those baking pans full of cat litter under my wings are for when they do that. It doesn’t happen often, but it does occur. 

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Just now, bluehighwayflyer said:

Geez. 23 years with two bladder equipped Mooneys and never once do I remember them having vented fuel. I must be doing something wrong. :)

You’re probably one of those guys who pulls the gas filler out of your car when it clicks off the first time too. Gotta jam the fuel in to see it do it’s thing. ;)

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22 minutes ago, Marauder said:

You’re probably one of those guys who pulls the gas filler out of your car when it clicks off the first time too. Gotta jam the fuel in to see it do it’s thing. ;)

It isn't full until it starts leaking!

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According to mooney drawings...

There are tiny holes in the ribs to allow air to escape.

this air would be resident in the tanks on the downhill section of the wing (closest to the cabin).

Going further out on the wing, up hill, there is a lot of air at the top of the wing.

There are a few Mooneys that have two fuel caps per wing.  Filling the up hill cap last is done intentionally. :)

How do The bladders handle the task of going around the ribs?

The tank vent is as far up hill as possible.

The 52 gal system is challenged because up hill, isn't very far... the tank vent itself is internal to the tank (a vertical tube open at the top) limiting how far up hill it can be. Not being perfectly level can put one wing's vent even closer to the fuel surface... letting expansion overflow occur.

A long body's 100 gal fuel system has a huge air space way out on the uphill wing.

Doing A geometry study, it would be possible to increase the fuel capacity by putting the fuel cap further out on the wing. It is clear that the tank is only being filled to the level of the wing's skin in the middle of the tank.

Seems kind of funny that the fill opening isn't as far up hill as the vent opening is...

An inspection opening would probably become necessary for some people to put their fuel stick in there for partial filling of the tanks.

PP thoughts on Mooney tank designs. Not a mechanic...

Best regards,

-a-

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  • 2 weeks later...

Finally got a chance to fly it this weekend. Went up for a quick test flight early Saturday, then picked up a friend and flew out to the Mooney wake. It was fun meeting some new mooneyspacers and catching up with old friends @Alan Fox  @carusoam @201er. Nice to finally put some faces to names like Byron @jetdriven. Now to finish my interior refurbishment project. 

 

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  • 5 months later...
On 10/2/2017 at 9:27 AM, N6758N said:

 

IMG_9554.jpg

Terry  do you happen to know if the parts and technique needed for swapping a leaking fuel drain on the bladders?  I found out the drain itself is P/N F391-18 but can't figure out if there's an o-ring, or the right torque.   I figure you know these bladders literally inside out now.     

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20 minutes ago, DXB said:

Terry  do you happen to know if the parts and technique needed for swapping a leaking fuel drain on the bladders?  I found out the drain itself is P/N F391-18 but can't figure out if there's an o-ring, or the right torque.   I figure you know these bladders literally inside out now.     

Hey Dev,

There is no O-ring on these, you may want to just buy the CCA-2500 from Aircraft spruce- they are identical to the other PN. As far as torquing them, there is no spec called out for in the O&N installation instructions. They are pipe threads so you just want to snug them up sufficiently so no fuel is leaking and then safety wire them to the aluminum plate. 

 

Bladder drain.pdf

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17 hours ago, N6758N said:

Hey Dev,

There is no O-ring on these, you may want to just buy the CCA-2500 from Aircraft spruce- they are identical to the other PN. As far as torquing them, there is no spec called out for in the O&N installation instructions. They are pipe threads so you just want to snug them up sufficiently so no fuel is leaking and then safety wire them to the aluminum plate. 

 

Bladder drain.pdf

$8 cheaper too!! Thanks for helping bolster my CB credentials :lol:.

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  • 11 months later...

Hi,

 

For N6758N

 

This is not the way I wanted to contact you, but didn't see another way. My name is Dean Murch. My father bought your plane new in 1968. Would love to hear from you. No biggie either way. 

 

Dean Murch 

Vancouver, wa

 

 

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Welcome aboard Dean!

Got any pics from the early days?  People and plane would be great!

58N belongs to Terry, a long time MS mechanic in the PA area... Terry has done some really good work recently promoting installation of modern fuel bladder systems and digital fuel floats in a couple of Mooney Models...

58N is in good hands!  :)

I can let him know you were asking... @N6758N

 

Best regards,

-a-

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