Flap Hinge Farings

This blog covers the installation of additional aerodynamic faring to the flap hinges of the Tucano.

Overview
The Tucano Replica uses a Semi Fowler flap necessitating a large external flap bracket consisting of two [2] laser-cut aluminium plates at each hinge point to create the necessary eccentricity.

While effective at their task they are dirty so it was decided to attempt to clean these points up.

Installation
A sheet of 1.0 mm carbon fibre sheet was purchased and cut to infill the area between the fixed hinge on the wing and the aerlion, this was fixed to the aerlion hinge with pop rivets.

Additional aluminium angle tabs were fabricated to secure the base and these were also pop-riveted onto the aerlion top skin. These tabs were fabricated from 1.6 mm thick commercial aluminium and profiled to look nice. The two faces mate inside the gap created by fixing the covers to the 3.2 mm hinge and are then match drilled and riveted.

While simple, it was time-consuming and hard on saw blades as the carbon fibre just eats them, finally they were cut using a Dremel Motor tool with a thin cutting disc using a metal guide to achieve a straight line.

With this completed, it was time to clean up the leading edge. 

Finished farings

Installed onto the bracket with carbon fibre
covers - note the angle brackets securing the
leading-edge.

It was decided to 3D print an elliptical leading edge in ABS plastic that engaged the gap in the brackets secured with polyurethane adhesive. A design was quickly run up on the CAD package and 12 hours later there were 6 leading edges and step farings and the builder slept through most of it. The leading edges were printed using a shell with a 1.5 mm wall and are weight-efficient. 

Note: most plastics are 50%of the weight of aluminium

The leading edge will be primed with plastic primer before the underside of the wing is painted.

Comments
Looks better and cannot hurt in the overall scheme.