A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Soaring
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Pawnee Fuel Tank Question

Thread Tools Display Modes
Old August 16th 18, 03:15 PM posted to rec.aviation.soaring
Larry Ruggiero
external usenet poster
Posts: 13
Default Pawnee Fuel Tank Question

Hello folks, did a little searching on past posts related to Pawnee tanks and came up empty handed, so here goes: ours is a C model with the bladder/liner equipped fiberglass fuselage tank. It's developed a leak at the bottom that I'm digging into. Discovered a poorly done previous repair that attempted to secure what the manual describes as a vent tube adjacent to the outflow shutoff valve. Except it's not the tank's primary vent, but appears instead to be a drain for fuel that might accumulate between bladder and tank in case of a leak. It's about a half inch aluminum tube that further mates to a tube out the bottom of the fuselage. Anyhow, it was glassed in place at the tank bottom and the repair has delaminated and loosened. Before further surgery, I want to verify that's its function. We removed the oval access panel on the top of the tank and sure enough, the tube does not penetrate into the bladder/liner. If I could post a pic here I would, but hopefully someone will know.

I've looked through the POH and service manuals; they only show one vent. The tank's primary vent line takes air from the sight gauge opening at the top and exits via a smaller tube out the top front of the tank, through an exit tube at the fuselage bottom. Thanks in advance.

Larry Ruggiero
Carolina Soaring Assoc
Spartanburg SC
Old August 16th 18, 11:49 PM posted to rec.aviation.soaring
Bob Youngblood
external usenet poster
Posts: 43
Default Pawnee Fuel Tank Question

I have a bit of experience replacing the fuel bladder in the Pawnee. The bladder can be repaired, the leak is probably coming from the area close to the bottom valve area. Contact Johnson Aircraft and they can give you datails on the bladder repair. Bob
Old August 17th 18, 12:56 AM posted to rec.aviation.soaring
[email protected]
external usenet poster
Posts: 406
Default Pawnee Fuel Tank Question

Old August 17th 18, 03:57 PM posted to rec.aviation.soaring
Larry Ruggiero
external usenet poster
Posts: 13
Default Pawnee Fuel Tank Question

Thanks. It’s all torn apart now, tank off the airplane, and I suspect fuel’s been leaking around the outflow hardware, based on some slight corrosion (from accumulated water in fuel) and absence of much sealant on the threads. Original bladder looks pretty good. The original drain mast must’ve broken off at some point and a poorly fabricated one grafted on. Leaked fuel helped debond the fiberglass patch holding the drain on. We’ve fabricated a much better replacement drain. Will bond that on, reassemble, and leak check before reinstalling.

Larry Ruggiero
Old August 18th 18, 03:46 AM posted to rec.aviation.soaring
Charles Longley
external usenet poster
Posts: 108
Default Pawnee Fuel Tank Question

This probably doesn’t help you. One of the Pawnee’s I work on has an aluminum tank. It’s a one time STC that some Boeing engineers came up with. I’ve done one repair on it. It’s a pretty cool design!

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Pawnee Center Fuel Tank Conversion [email protected] Soaring 8 May 19th 13 01:48 PM
Pawnee fuel tank vent drip Mike McCarron[_2_] Soaring 1 November 3rd 08 01:56 AM
Pawnee D left wing tank needed in Salida, CO Birdbones Soaring 1 May 21st 08 09:01 PM
OK, I'm going to ask another fuel tank question. Lou Home Built 9 April 22nd 07 12:46 AM
Saturn V S-IC-T (static test stage) fuel tank assembly is mated to the liquid oxygen (LOX) tank 6416666.jpg [email protected] Aviation Photos 0 April 12th 07 01:33 AM

All times are GMT +1. The time now is 11:15 AM.

Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright 2004-2019 AviationBanter.
The comments are property of their posters.