Fuel tank Questions

[nacoblio]

So I am getting to the point I can start thinking about sealing up the tanks on my RV-7 build. I have a couple of questions for the group.
1. Flaring tools. Is there a need to flare something on the aircraft in a confined space? I am looking at the this flaring tool that wont work in a tight space.
http://www.aircraftspruce.com/catalo...ringtools2.php . Is this something that should be a concern? I dont want to buy more than one tool if I can get a way with it.
2. Fuel return lines. How many people have needed them. I havent even started to think about engines but I dont want to have to install a fuel return line after the tank is sealed. Is it worth it to just install one now in case I need one later?
3. Cork gasket. I have been reading and it looks like some people recommend just using tank sealant in place of the rubber gasket. Has anyone had the cork gasket fail?
Thanks for reading my long post. I appreciate all the help this group provides.

[Carl Froehlich]

I suspect you will get a lot of opinions - here are mine:
- The Rolo flaring tool (the one on your link) is the tool to use.
- I add a 1/4? AN bulkhead fitting to the left tank for fuel return. Trivial to do now. On the RV-10 I did not use it, so it just got a cap. On the RV-8 I got the Van?s engine with the AirFlow Performance injection system so I will be using the return line. Along the same topic, I added a 3/8? AN bulkhead fitting on the right tank in case I ever wanted to plumb a ferry tank. It will be capped until then. The plan being the ferry tank would be pumped into the right tank after the right tank is down 10 gallons or so.
- I built many tanks using the cork gasket. I put proseal on both sides of the gasket. My thought was that if I ever need to pull the access plate cutting through the gasket might be easier. Never had to do it, so no data point for you. I do not recommend using the float sender rubber gasket. Just proseal.

Carl

[rv7charlie]

No doubt that's a great flairing tool, but I (and the person I borrow it from) have made a bunch of perfectly serviceable flairs using a 'skinny candy bar' shaped tool that's about 1/4 the price. Significantly more compact, as well. 'You pays your money, and you takes your choice.'

Adding a return line to a finished tank is a *lot* harder than capping an extra fitting....

Lots of cork (and rubber) gaskets have leaked. (Of course, lots of prosealed joints and rivets have leaked, too...) I started using this stuff:
https://www.permatex.com/products/ga...lange-sealant/
several years ago, and I haven't had a leak yet. No gasket; just the sealant. It never hardens, so if (when) you need to remove a cover to fix a proseal leak, it's very simple & easy to remove/replace the panels.

Charlie

[David Paule]

My Cessna uses a cork gasket. When I install one, I coat it with oil on both sides. They seem to last a couple decades but then need replacement.

On my RV-3B, I used tank sealant, but I used the access hatch kind. It's an ugly pink-gray when mixed. Here's an example. I got mine from Skygeek.

Incidentally, there's also a Type A sealant that's like regular tank sealant except lower viscosity. It's handy to put on edges and individual rivets, using a syringe. FYI.

Dave

[nacoblio]

Thanks for all the info. I appreciate the help.

[airguy]

Add the return line now - so much easier today than after you seal the tanks, and you just cap it until/unless you need it.

I didn't use the cork gaskets, I just prosealed it straight onto the tank. I had to remove them once and it came apart fairly easily with a razor blade to start the separation and then a small flat-blade screwdriver and then a larger one.

[wirejock]

My flare took is a Rigid.
I didn't plumb for a return line. Sticking close to plan and the plans don't call for it.
Consider TS Flightlines for the more complicated lines like tank to valve. No need to fight with flaring inside the airplane.
I used the cork and Titeseal but plan to open the cover and seal it with proseal before final assembly.

[Bevan]

During the building phase, I plumbed return lines to both tanks through a duplex fuel selector. The return lines are used regularly by the purge valve (Airflow performance) and occasionally with a removable baggage area ferry tank. I’m very happy to have the return lines already in place.

Bevan