Author Topic: Fuel bladder installation  (Read 522 times)

Barry Dechert

Fuel bladder installation
« on: December 22, 2017, 11:25:53 AM »
I am looking for someone with experience installing Helio fuel cells. The preferred method or better yet the best method.
The military manual mentions felt which is taped or glued I imagine to each of the hangar locations, should I install felt at each location, or just tape it like it wasn’t?
Installing these bladders the hangars are installed first before rolling it in the wing or after?
Any additional input procedure wise installing bladders appreciated.
Some questions may sound dumb but I don’t have any experience with bladders.

Louis

Re: Fuel bladder installation
« Reply #1 on: December 22, 2017, 10:52:34 PM »
Please specify Helio model

jmetzler

Re: Fuel bladder installation
« Reply #2 on: December 23, 2017, 04:07:59 PM »
I've installed a lot of bladders over the years. unless it is a 700 or 800, they all install the same.

First thing to do is check the receptacles to be sure the tabs are not bent. Take a hanger and check each receptacle to be sure they go in. Nothing more frustrating than getting down to the last one and the hanger won't fit...

If they are all good, all the edges and rivets need to be covered with vinyl tape to protect the bladder. This includes all the edges and rivets in the liner. Sometimes the tank people send a roll of tape more like duct tape. That works fine too. Takes a little time and fussing.

If it is new bladder from Floats and Fuel Cells, you will find they install a nipple on the inside for return fuel. I think you have an H391B so no aux tanks. If you had aux tanks, you'd need to open the hole for the inside nipple and cut a hole in the wing rib as they don't match the original tanks with the sandwich fitting.

The hangers do get installed and tightened in the bladder before installing. First replace all the shaft 0-rings inside the hanger assembly. I like to use a little DC-4 for lubricant. Then assemble the hangers, tighten the nuts and install the check nuts. I like to align the check nuts with the lock nut for the step below.

Stuff it all in the hole and lay it out starting the nipples in the ribs but don't finalize their position.

I like to start at the front of the tank as they hook from front to back. You can use a deep socket to go over the nuts and have a handle for improved comport.

They can still be a pain, but eventually you'll get all the hangers installed and then you can finish pushing the nipples through the rib and spar holes.

Install the sending unit, (takes 2 gaskets) check calibration while the tank is open. The filler neck also takes 2 gaskets. The bottom plate only needs one gasket. You can take bolts and cut off the heads for line up pins for the sending unit and lower cover. They really help make it easier. You don't need them for the filler as you can reach through the opening.

Jim

Barry Dechert

Re: Fuel bladder installation
« Reply #3 on: December 23, 2017, 06:43:20 PM »
My apologies I should have stated Aircraft series. Yes H391B s/n 091.
I read couple of different manuals and for me wanting to do this correctly, and doing the easiest way to get it done the manuals were lacking information.
I see were the manual says to use a rubber hose the idea of a scocket on the pair of nuts (🤭) would work also.
I understand & I was apprehensive about rolling it up squeezing it through the oval opening with the hangars installed.
Jim, thank you I just don’t have experience installing bladders.
The one part I need help with are the ‘O’ rings. Maybe I should give you a shout after the holiday.
Merry Christmas to all onboard have a safe one.
Barry.