Mailing List lml@lancaironline.net Message #26100
From: Yacht-Pool <yacht-pool@forsikring.dk>
Sender: Marvin Kaye <marv@lancaironline.net>
Subject: Re: [LML] Extended Fuel Tanks
Date: Thu, 14 Oct 2004 06:00:34 -0400
To: <lml@lancaironline.net>
Hi Folks, Lancair 360, third fuel tank in the wing, what size pipe(s) and material are people using to connect the tanks?  Any one way valves used?  My Vent is already in.  Also, did anyone encase the bellcrank nuts on the gasoline side?  I can't find anything on the archive.

I built my 360 wings with the extended tanks. Bofore doing so, I called Lancair and they faxed me a rough drawing of the system.
The drawing from Lancair suggested that the lower channel be made some 3" wide and 1/2" high. The upper (air) channel should be made of one 1/2" aluminum tube (revised from a 3/8" tube). Lancair suggests incorporating slosh doors, but I do not like the idea of having moving parts built into the wing, they won´t be serviceable in any way and it is impossible to see whether or not they get clogged up with Hysol at close-out. Imagine the fun you´d have, if they got stuck closed! Talking to other builders convinced me, that slosh doors are not needed.Unfortunately I no longer have the drawing from Lancair, some other builder got it a while ago, but my system is built according to Lancair´s specs with the following modifications:

1. Slosh doors skipped

2. Lower channel some 3.5" wide (I made the channel over a piece of 1/2" foam, edges rounded, glued to flat table and covered with release tape).

3. Upper channel made of BID instead of aluminum. I covered a piece of broomstick with release tape, put 2 BID around it, split the bid with a utility knife thus producing two pieces of channel, fuel sealed the inside of the channel and the wing skin area covered by the channel with two coats of resin, micro´ed the channel in place and covered it with 2 BID. This is all together easier and less leak prone than the aluminum tube.

4. The drawing did not mention how to fuel seal the nutplates for the aileron bellcrank. I covered them with a piece of 1/2" foam, edges rounded, and 3 BID.

One word of advise: Fabricate and reinforce your cap strips first! Then incorporate the lower channel and secure it in place with 2 BID on both sides of both bulkheads.

Regards
Tim Jorgensen
360FB  /  50%

Image
extd_fuel_tanks.jpg
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