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AirbusPilot

Well Known Member
Hi All,

I need some advices here, I am building and RV-8. Right now I am finishing the fuel tanks, Proseal not a problem:D but I am not sure about how safe and how necessary is to install the antihang mod to the tanks if you are installing the flop tube. Please check the pictures and see what happens to my flop tube when I rotate the tank, if I do not install the antihang there is no way that the flop tube get stacked anywhere so why vans recommend this mod.

PLEASE CHECK AND ADVICE!!!!!!!!!!!!




 
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Interesting

I used a flat piece of aluminum per the plans and I dont see how the end could get underneth it. Your installation definately looks more elegant, but it might lend to this condition.
Just my 2 cents and I am by no means an expert.

Looking forward to others comments.
 
I don't like that at all!

I have a 7 so if i remember my anti hang looked different.

No way would I put that in there that way!

Frank
 
I don't have one

I did not install an anti-hang device in mine. Don't remember if it was the length of my tube or shape of the stiffeners or where i put my backflow door, has been too long, but on mine installing the device per plans was not needed. I could rotate the tank in any manner posible and there was no surface for it to catch. So did I did not install it.
 
Anti-hang

The purpose of the bracket is to keep the flop tube from getting caught in the corner between the stiffener and the rib and to keep it out of the way of the trap door...a much shorter bracket will do the job and won't let the tube get caught under it.

YMMV.

Mike
 
One other thing to be careful with......

One other thing to be careful with......

Before you close up that tank, be extra sure you have done the best job you can on sealing the fuel level sender on the flop tube tank. I would pro-seal the @#$!#$ out of it. If it starts leaking a few years down the road, you cant fix it without taking the tank off!:(
 
Clean tanks!

By the way, you did a nice job on those tanks - looks very clean. Mine look like a pro-seal bomb when off once everything was said and done.
Have fun out there!
 
panhandler1956 said:
By the way, you did a nice job on those tanks - looks very clean. Mine look like a pro-seal bomb when off once everything was said and done.
Have fun out there!
Click to expand...


Yes I tried to keep the tanks as clean as I can, I hope they are leak free too :rolleyes: will test next week. Look at the picture form the outside very clean.




 
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Yep, ditto on the pretty tank comments -- very impressive. Mine looked horrible! I'm glad all that Proseal is hidden. ;-)

I don't intend to hijack the thread, but I think people should consider seriously if they will ever need flop tubes. They're useless unless you're going to put in FI and inverted oil. They're just one more thing to break (they're a moving part).

I have the fixed pickup tubes and have all sorts of fun doing acro, including hammerheads and humpty bumps. I don't miss the flop tubes one bit.
 
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Jamie said:
Yep, ditto on the pretty tank comments -- very impressive. Mine looked horrible! I'm glad all that Proseal is hiddean. ;-)

I don't intend to hijack the thread, but I think people should consider seriously if they will ever need flop tubes. They're useless unless you're going to put in FI and inverted oil. They're just one more thing to break (they're a moving part).

I have the fixed pickup tubes and have all sorts of fun doing acro, including hammerheads and humpty bumps. I don't miss the flop tubes one bit.
Click to expand...

Jamie,
I kind of agree with you on the practical aspects of having a flop tube, which is part of the reason I put the flop tube in one tank and the regular pickup in the other.
 
From the standpoint leaks on them, more proseal = better. I've resealed a -6 tank that looked pretty... not enough proseal though.
 
A friend (916Romeo) had a leak in one of his tanks on his -7. After draining and removing the tank, he quickly found his leak.

He also found that the flop tube components had separated and were rolling around in the tank!!!!!!!!!!!!!!!!!!!!!!!

Please do not forget to safety wire the fittings together (I didn't see any in your photos).
 
gpiney said:
A friend (916Romeo) had a leak in one of his tanks on his -7. After draining and removing the tank, he quickly found his leak.

He also found that the flop tube components had separated and were rolling around in the tank!!!!!!!!!!!!!!!!!!!!!!!

Please do not forget to safety wire the fittings together (I didn't see any in your photos).
Click to expand...


Yes I safety wired the flops tubes

 
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Hi Greg,

The pick up end is sticked with proseal, do you think is enought???

Cheers,

Fernando

 
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I don't know about using proseal as a 'glue' like that. The one thing I have been told many times is that you should never use any kind of compound or 'teflon tape' anywhere in your fuel system. The chance of particles or 'globs' coming loose and blocking fuel flow increase. The one exception is something called Fuel Lube. I will call 916Romeo tomorrow and see if he will chime in here.
 
Flop Tube Pickup End-Proseal

My flop tube came pre-fabbed from Van's with sealant "gluing" the pickup end to the assembly as shown in the photo above.

I thought about adding safety wire, but a wrap of wire on the end of the flop tube may have it's own issues-like chewing up the ribs, skins, etc. as the tube moves...I plan to close up this tank in the next week so any thoughts will be appreciated.

Mike
 
An alternative and a question

I wasn't as clever as AirbusPilot, so I just made a cover to protect the o-ring from the edge of the rib hole:
20070811-06-tn.jpg


Regarding pretty tanks, I tried to keep mine pretty too and even thought about skipping the addition of proseal fillets.
In the end though I chickened out and added proseal fillets and dabs over all the rivet heads:
20070825-01-tn.jpg
20070825-03-tn.jpg

20070730-01-tn.jpg


I also like AirbusPilot's covering of the rib hole altogether and simply adding a few smaller holes.
It looks like a better solution to keep fuel in the inboard bay. Is this the way Van's is recommending to do it now?
 
Hi Mike,

Yes flop tube clunk comes glued with proseal from vans and I think that should be more than enough to keep it tight. Your tank look nice and clean congratulation!!!.

I have made some more improvement to the tanks that maybe you would be interested.

1.- I have glued the viton oring with proseal to the clunk.

2.- I have changed the poor quality BNC connector that came with vans capacitive fuel sensor kit for good quality anphenol ones.

3.- Also I have changed the poor quality nylon spacer that will degrade over time with fuel for beautiful and stronger ACETAL ones.

Keep the good work,

Fernando










 
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