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.

Panel Labels

This blog covers the manufacture and installation of panel labels.

Overview
One of the aims of the build was to capture some of the sense of a military cockpit and not have just another Sports Aircraft installation.

To achieve this a number of Tucano cockpits were studied and the essence distilled. One reason that these cockpits appear so overwhelming in the complexity of purpose created by the mission need of a particular military aircraft.

RS Warbirds Shorts Tucano T1

This Tucano has no more hardware than say a Piper Arrow but they have been grouped so
that all the gauges, switches and breakers are located on a panel not scattered in various locations in the aircraft.

The colour scheme could be best described as military with style created by the use of a yellow border and highlights in the cockpit versus plain white. This was not my idea but was borrowed from RS Warbirds upgrade on a civilian Tucano T1.

Labels
The creation of the artwork for the labels was covered in a previous blog so this blog will expand on this previous posting.

De-burring Tool

After reviewing the use of laser-printed labels it was suggested to be by Joe at Marwen to consider sublimation printing of the graphics directly onto aluminium. This was trialled with the finished surface exhibiting all the toughness of glass with a matching gloss. Consideration was given to an overspray of satin clear but the toughness of the surface was lost so it was decided to accept the gloss.

The finished panels must be cut using a sharp guillotine as tin snips create a chipped edge that is hard to remove. The edges are then be finished by polishing on a hard flat surface with 400 grit wet/dry paper while radiusing the corners just slightly [they are sharp].

Diamond Drill Bit

Holes should be pilot drilled using a 1 mm twist drill and then enlarged to their finished size using a sharp [new] step drill. 

Larger holes for gauges should be created using a diamond drill bit, these can be found on the Bay and are of good enough quality for one project.

Once drilled a guage hole may be enlarged using a deburring tool and then the edge polished by hand using 400 grit wet/dry.

This finish should be treated at all times as a thin coloured glass coating and very few issues will be seen. 

If it is necessary to dull the panel the clean with an alcohol wipe and then apply two light coats of two-pack satin clear.

The finished panels are bright and clear and tough as glass...!

Getting there

Creating Graphics - Update
The CAD package created the necessary dimensional control for use with PC Paint but when transferring text some pixelation may occur. Once you have a graphic of a known size it is easy to just type the text in PC Paint and this creates a crisp clear text on the graphic. This pixelation is not bad but if you do seek perfection well you can get closer using the technique described.

For those seeking perfection, you will need to use a vector-based package like Coral Draw but with the right juggle, the process described works.

Comment
The builder is very happy with the results and it is possible to create high-end graphics using basic packages.

To contact Marwen click on link opposite - Marwen

Safety Note
The corners are very sharp after trimming so do not try to step drill larger holes without clamping or bracing of the plate if the tool grabs it will rip your hand to pieces.

Yes, still can count to 5 - just...!

Entry Step

This blog covers the step and a drag reduction attempt.

Overview
The Tucano has a 20 mm OD tube fixed onto the fuselage hanging under the fuselage creating an easier entry via the port wing walk. This makes entry easy and well worthwhile installing.

The diagram below shows the relative drag created by a tube versus a streamlined tube.

Installation
The first task was to cut the hole through the skin using the mounting point as a guide. As this is no simple circle, so with a little luck one of the rivet holes was on the tubes centre line. This hole was enlarged to 1/2'' OD using a step drill then further enlarged using 1/4'' chain file. The hole was enlarged carefully until the file would run parallel to the inside face of the fuselage mounting tube.

A trial fit confirmed it fitted correctly, then it was secured using 2 x M6 bolts to the fuselage using the pre-drilled holes.

Printed farings for step
and flaps

Drag Reduction - a little
A profile was printed using a 3D printer in ABS plastic to fit onto the face of the tube that was supplied by the factory. These were created as two separate profiles with the lower one fixed to the tobe and the upper fitted and profiled to the fuselage. A fillet of polyurethane adhesive blended the upper profile into the fuselage.

Lower faring fitted

Comment
Simple clean up and looks tidy but compared to the fake exhaust looks like a waste but it all about balance even a little were possible.

A similar clean up was done with the flap hinge and this will be covered later.

The use of ABS is a suck and see as it doses soften at about 70C but is used extensively in automotive interiors and appears to stand up well.

To follow the work find the aircraft on Facebook under Gary Spencer Salt