Overview
The factory is currently upgrading the assembly manual to show routing for the fuel lines but my kit is an earlier model and the work here is for record only but may still have some value.
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| Sample drawings from the new Tucano manual Removes all the builder guess work |
Manufacture
The lines for supply and return are all aluminium 3/8'' giving a bore of 6.5 mm within the manual specification and was sourced from AeroFlow in a coil form.
One of the issues of coiled aluminum the need to straighten for aesthetics and this cannot be achieved by hand or rolling across a floor. Searching the web located a tube straightener from Kwix UK that seemed to be right for the task and that was cost effective.
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| Kwix UK straightener |
Straightening tube by hand to get the worst of the bends out then the straightener was run along the tube, multiple passes at different point around the tube's circumference worked best and once the tube is straight the roll can be run along the length in a rotating action to obtain that final adjustment.
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| Firewall bulkhead fittings |
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| Gasolator bulkhead fittings |
Note: The tube straightener creates fine tram lines but are removed when worked as described.
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| Flaring tool |
The length of the tube at the firewall end was flared using a Rapid 37 degree flaring tool then inserted through the aircraft using holes drilled for purpose. At the firewall AeroFlow 45/90 degree full flow bulkhead elbows were fitted and the lines fixed using AN nuts. All flares edges were polished using 400 grit aluminium open cut to reduce the chance of cracking.
All lines were protected running through the bulkheads on commercial grommets with lines supported by automotive line separators. Separators did not come in a suitable size so before installation 1/4'' separators were drill to 23/64'' to allow firm clamp on the pipe.
Note: Sharp edges created by drilling were all chamfered before installation
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| Barb Elbow |
Connecting the supply and return to the tank AeroFlow hose and AN6 - barb fittings were selected allowing a 3/8'' tube pickup and 5/16'' return lines secured with S/S worm drive clamps.
Gascolator / Fuel Filter
With the firewall filling and guessing it was only to get fuller a alternative location was sought for the gascolator and filter so when in doubt read the RV8 blogs. A number of these builder have chosen to place the item in their wing routes and this was seen as a possibility on the Tucano.
After thinking about the issue it was decided to install them both under the co-pilot rudder pedal foot rest as this was already a removable cover to allow access to the turnbuckles for the rudder.
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| ACS Gascolator |
An extension to allow the valve to be accessed from the underside of the skin for fuel drain checks will be fitted when the skins are installed.
Allowing this bracket to be removed with one bolt should mean that the gascolator and filter can be removed for servicing.
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| Gasolator and filter Required for the bladder tanks only |
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| BRACKET DIAGRAM |
A series of Aeroflow swivel elbows were installed with suitable hose and sized to prevent chafing when in service.
Note: These are very expensive fittings but were required to achieve the design intent
Comment
Many days were used to work out the routes then gain the courage to drill the bulkheads and assemble the materials just to get it all to fit and look like some thought had been applied.
The factory design will allow the lines to be formed on a bench - Half of mine were finished under the aircraft with a flaring tool that proved to be hard to control away from the bench.
While Aeroflow tube is very ductile and easy to form by hand it is crushed to the die size of the flaring tool when fully closed and if a re-flare was required the tube had to be cut back a minimum of 25 mm.
Tube straightener indispensable - worth every penny.
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