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  #41  
Old 01-16-2010, 09:25 AM
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Mel Mel is offline
 
Join Date: Mar 2005
Location: Dallas area
Posts: 10,768
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Quote:
Originally Posted by diamond View Post
How are the tanks on the RV7 and 9 different than the 12? I know they're larger, but are they of the same general design?
The RV-7 & -9 have integral wing leading edge tanks.
The RV-12 used an individual tank mounted in the baggage compartment.
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Mel Asberry, DAR since the last century.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
<rvmel(at)icloud.com>
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  #42  
Old 01-19-2010, 08:09 AM
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JerryG150 JerryG150 is offline
 
Join Date: Nov 2006
Location: Bradenton, Florida
Posts: 348
Unhappy it's official ...

It's official ... my window leaks! I put the tank down on it's window side, added water and it leaks. Now I realize I shouldn't have attached the top before my water test. It's too late now. Since I'm out of fuel tank sealant at the present time there's nothing I can do about it today.

I wish I could just seal the entire window area and be done with it.

I imagine I'll remove the top, order sealant and solid rivets (order a new window & new reflector plate?) and try again.




Later ...same day ...

I removed the top of the gas tank (lots of solid rivets to drill out), washers, nuts & screws around the window but I can't get the window and reflector plate off with out damaging them. Therefore, I think I'll wait for the sealant to arrive, then I'll slather sealant into the cutouts in the window where the screws fit into, on all the screws, nuts and washers and hope that does the job. If not I'll build a new tank with all new parts. I'm not the first to have to do that and I probably won't be the last.

Even though I wish there was no window ... this failure seems to be entirely mine. Others have successfully completed this task and I would guess I just didn't use enough sealant the first time around. Oh well ...
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"Time, be careful how you spend it ... cause it isn't going to last."
VAF #1037
Reserved N124JG for RV-12
"12 for Jerry G.
http://jerryg150rv12.blogspot.com/

Last edited by JerryG150 : 01-19-2010 at 12:34 PM. Reason: Later same day
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  #43  
Old 01-19-2010, 11:51 AM
JohnF JohnF is offline
 
Join Date: Jan 2005
Posts: 458
Default Leaks

Jerry,

Did you do a 'balloon' test first? I am wondering if that was OK or if you went directly to the water test. I did a 3 or 4 day balloon test and that was OK but I wasn't going to do any liquid test, but after your experience I may put a gallon or two of gas in and let it rest of each side for a day or so and see if that confirms what the balloon test showed.
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  #44  
Old 01-19-2010, 04:00 PM
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JerryG150 JerryG150 is offline
 
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Location: Bradenton, Florida
Posts: 348
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John,

I just added water, before I put the circular plates on (fuel sender being one of those). No balloon test as of yet.The window leaked in 2 spots, I think, then I tightened the screws "a wee bit more" and only a drop in one spot came out ever so slowly.

Now looking for 5/32 or 3/16 solid pop rivet to fill a few drilled out rivets in the top skin. Noone said it was going to easy ... especially for a first time builder.

Jerry
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"Time, be careful how you spend it ... cause it isn't going to last."
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Reserved N124JG for RV-12
"12 for Jerry G.
http://jerryg150rv12.blogspot.com/
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  #45  
Old 01-19-2010, 06:51 PM
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L'Avion L'Avion is offline
 
Join Date: Apr 2007
Location: Memphis
Posts: 159
Default Leaky tank woes

See my post:
http://www.vansairforce.com/communit...iberglass+tank

I've had these tanks filled with either avgas or mogas for nearly two years now, and no problems, and no leaks.

All the Eze aircraft have had glass tanks for years with zero problems.

I am not a builder, but having had a VariEze for many years, I thought, why not fiberglass tanks; and my aluminum-skinned tanks have been the solution for me. Maybe the best of both worlds, eh?

A short story of building things: Many years ago, me old Dad was a carpenter superintendent on many heavy construction jobs and was often approached by men wanting work. His interview consisted of asking applicants to build one of two things, a good usable sawhorse, or a 1' square box. Few had any idea how to build a sawhorse, and many tried the box - few passed muster. One outsanding applicant, "No problem." And, in a few minutes said applicant had constructed a perfect box held together (temporarily) only by the perfectly cut 1' squares each cut on a 45 degree angle so as to fit together perfectly. The old man told him that lunch was from 12:00-12:30, start work, now.

Similarly to build a box of aluminum sheet metal is a daunting task; and a leak proof box to hold fuel is even more so daunting. But, fiberglass tanks, however sloppily built, if there's enough resin everywhere, most likely won't leak.

Standing back for the flames from aluminum construction purists.

Barney, in Memphis
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  #46  
Old 01-19-2010, 07:24 PM
Mark Henderson Mark Henderson is offline
 
Join Date: Oct 2008
Location: Napa, Calif
Posts: 274
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I like the engineering on the 12 a lot. The one aspect that has troubled me from the start is a big riveted aluminum box full of very volatile fuel sitting right behind my head. There are too many NTSB reports of minor accidents which turned fatal when the fuel tanks ruptured. The Van's tank is very light, and it is always great to save weight. If you showed up at any track with a car that had that for a tank, they wouldn't even let you off the trailer. A real fuel cell is too heavy, but there are alternatives. I have a friend who builds winery equipment who is doing some preliminary design work for a welded tank with safety foam. It will weigh more, and be more expensive. I will be curious to see exactly what the numbers are.
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  #47  
Old 01-19-2010, 08:26 PM
ARPENN ARPENN is offline
 
Join Date: Feb 2009
Location: West Ossipee, NH
Posts: 141
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After all my fussing the fuel tank came out pretty good. I had 4 leaks initially. one at the ballloon connection, one at the air valve connection and two on the cover screws. I tightened the clamps at the connections and gave the screws a 1/4 turn, then it remained airtight for two days ( I measured the circumference of the balloon ). Don't know if it will hold liquid though.
I primed the tank, including around the windows. It looks pretty good. I had only one tiny spot that leaked sealant and got no paint on the glass. I masked the glass with dots of cardboard from a Christmas sweater box. I used a 1/4" deep socket as die to cut them out and they fit perfectly. Then just popped them out after painting.
You can see this on http://www.Mykitlog.com/ARPENN

Art Pennanen
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  #48  
Old 01-20-2010, 05:54 AM
Peterk Peterk is offline
 
Join Date: Mar 2008
Location: Texas
Posts: 1,378
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Quote:
Originally Posted by Mark Henderson View Post
I like the engineering on the 12 a lot. The one aspect that has troubled me from the start is a big riveted aluminum box full of very volatile fuel sitting right behind my head. There are too many NTSB reports of minor accidents which turned fatal when the fuel tanks ruptured. The Van's tank is very light, and it is always great to save weight. If you showed up at any track with a car that had that for a tank, they wouldn't even let you off the trailer. A real fuel cell is too heavy, but there are alternatives. I have a friend who builds winery equipment who is doing some preliminary design work for a welded tank with safety foam. It will weigh more, and be more expensive. I will be curious to see exactly what the numbers are.
I have an aquaintance who has taken the measurements/baffles everything and is prepared to make aftermarket fiberglass for $375. The problem is: if you go ELSA you have to build the tank as is, get it certified, then change it. In my case (and several others) once we got the existing tank not to leak, we covered the sight holes (the source of all the leaks) and all is well. Replacing it now for $375...and the weight change...is not a real popular idea. I think if Van's ever has it put on the 51% list you might get more interest. Then you could put it in from the beginning and not even buy the other one.
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  #49  
Old 01-20-2010, 07:09 AM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,070
Default Air versus liquid test

It is better to do an air test first. Air will leak through a much smaller hole than water will. If the tank does not leak air, then it will not leak water either. If an air test is not done and there is a very small hole that does not leak water, then that hole might get bigger with time. A very small hole might not leak liquid gasoline but could leak gasoline vapor.
Joe
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  #50  
Old 01-23-2010, 03:16 PM
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JerryG150 JerryG150 is offline
 
Join Date: Nov 2006
Location: Bradenton, Florida
Posts: 348
Default yikes!

Today I reworked my fuel tank. I used the qt. sealant can and mixed it 10 to 1 using a weight watchers scale for the weight proportions. I have a hunch my sealant will never set up. I must have messed up again. A note came with the qt. sealant

"that it will take up to 3-7 days to cure and will remain soft for up to 30 days in cool weather ... be patient! Van's"

The little jars and caulking tubes of sealant I used before, set up in about 2-3hours. I'll give this stuff a few days and see if anything begins to set up. Here's hoping it does eventually set up and then doesn't leak.

I'll be very surprised and happy if all goes well. May just have to build another tank.
__________________
"Time, be careful how you spend it ... cause it isn't going to last."
VAF #1037
Reserved N124JG for RV-12
"12 for Jerry G.
http://jerryg150rv12.blogspot.com/

Last edited by JerryG150 : 01-25-2010 at 12:08 PM.
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