Overview
This kit was originally supplied with the Explode Safe tanks but on Franco last visit the issue of weight came up. After a bit of discussion it was decided to exchange these tanks for a pair of the new factory aluminium tanks - saved another 3 kg.
Installation
The factory now supplies detailed drawings / parts list and instructions so this will not be covered with the tanks installed factory assembled.
The first task was to cover all the rib flanges with cork or foam tape. As the builder has access to 5mm foam sheet it was decided to install this product. It was split into 25mm wide strips using a box cutter with the flanges having 30 mm wide carpet tape applied.
With the tape trimmed to match the flanges, the backing tape was removed and the foam applied with the result begin neater than adhesive.
Note: Selected foam is the same type of material used for concrete expansion joints, this product is manufactured by J&M Hobbies in Australia for hobby track underlay.
Next rib #6 was completely in-filled with foam to a thickness of 10 - 12 mm, a cardboard template was made then traced onto the foam sheet and two [2] profiles cut and fixed using the carpet tape.
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| Nose rubbers |
The final task was to install rubber channel onto the nose area as a safety measure. Due to the tight radius the rubber channel had to be cut to allow it to be glued to the radius. This was achieved using a Xuron Rail Nipper #2175B. What is different from just side cutters is these are a flush cut shear on one face and are sharp, ideal for these tasks.
With these tasks complete a tank was slid into the wing and the skins clecoed back into position
Note: this task is part of the final assembly of the wing and finishing with the final drilling of all rib mountings holes from 2.5 to 3.2 mm then dimpling to allow use of countersunk rivets.
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| Fuel tank trial installation |
With the ribs aligned the tank was positioned [chocked] using foam wedges. Next the position of the fuel cap inlet was measured after installing the neck with two [2] temporary bolts. This was checked and rechecked then the skin cleoced back onto the wings and the position marked.
Note: before the skin was installed a cardboard cover was fitted to the neck inlet with rivet lines used as datum's for all measurements
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| Measurements |
A 3.2 mm hole was drilled on the marked center and through the cardboard cover, next the skin was opened to check the position on the cardboard. With the hole confirmed on center the skin was re-cleoced and hole saw used to cut a opening to suit the filler.
There is an amount of adjustment [movement] so it was decided to use the fuel cap as a locating jig for the over dress cover.
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| Checking hole center from trial drilling of the skin Care had to be exhibited to avoid damaging the filler neck under the cardboard |
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| Hole cut for filler and cap - skin removed and all burrs dressed and polished out |
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| Filler opening backing plates |
The caps outer ring was screwed to the filler neck and the cap fitted, then the outer cover A was fitted over the rim of the cap and aligned, finally the holes [2.5 mm ] were transferred to the skin.
With the holes drilled part A & B were riveted together with counter sunk rivets and placed to one side for final assembly to the underside of the skin
Finally the cap was removed revealing the tank neck and opening into the tank.
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| Drilling holes for outer cover using the cap backing plate plate that is mounted under the skin |
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| Finished assembly after cap removed |
The next task was to install the fuel senders, drill an access hole and again the same procedure was used. Next the fuel sender as assembled and its position in the tank assessed as the factory now includes a thick spacer to be used if required - it was not required for this aircraft.
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| Fuel sender |
An access hole for the fuel drain was drilled again using a trial hole - if measured carefully any small error can be removed when the access hole is cut.
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| Fuel drain |
The factory sump was fitted with a 1/8'' NPT drain valve and plug at the tapped side port. All these are sealed using Aviation Gasket Cement #2 which is a semi-permanent sealant.
Note: cover any incorrect hole with tape - there are no second chances with a hole saw.
The final task will be to install covers and rivet nuts and this will be done at the final assembly of the skins.
Comment
One small error was cleaned up with the hole saw but it just take time and care especially with the access holes - there is no easy fix for a error
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