Painting

Comment

Painted, at last, Painted at last.........!! 

When he awakes, tell him there are a few items 

to be still to be painted ..!!

Painting Markings

This blog covers the aircraft's war paint

Overview

Camouflage Details

One of the first issues encountered was identifying the colours used on the markings and regardless of how much searching no commercial standard could be identified, unlike the main colours. After discussing this with the paint supplier it was decided to use the BS381C standard and find colours that were as close as practical. With that decided an order was placed for the six [6] different colours that had to be used.

Dark Earth - BS381 350 plus 22.5 K73 per liter {match to Vaellio Model Paints]

Forest Green - BS381 241

Duck Egg Green [Eu de Nil] BS381 216

Underside - Duck Egg Green BS381C

Roundel Blue - Roundel Blue BS381C 110

White - Pure White W351

Bold Red - BS381C 564

Canary Yellow - BS381C 309

Lt Aircraft Grey - BS381 627

Black - Satin Black K73

An issue that had to be resolved was the orange peel from applying 2K clear to the port wing. After completing this task it was decided that a coat of base should be re-applied but it crinkled everywhere it contacted any clear that remained, a quick read showed that this is a no-no. 

The problem had to be resolved by stripping back the wing but it was now clear that all base colour would have to be applied before attempting to apply the 2K clear.

As an attempt to control weight it has been decided to use vinyl film and spray paint for the roundels and tri-colour. A low tack vinyl was selected and were cut after producing the necessary graphics using the sketch above to obtain the correct proportions allowing all these profiles to be masked up in one operation.

After the airframe and wings were in undercoated, the vinyl is applied after the relevant colours applied by removing the relevant mask, finally when each colour was dry each mask was reapplied to complete that marking. 

Applying these decals is a skill but the use of clean water with a solid squirt of washing detergent is a must. They were floated into position and massaged into their correct location. 

Disposable towels are used to remove excess water with particular attentions paid to edges to ensure they are as tight as possible. The large decals we all cut into manageable segments for this task as they cannot be handled as a single unit.

Generally, I started with the dominant colour blue, next a white after applying a light coat of primer, then finally the red. The side was the same except started with the yellow and primer as required. Finally the tail tri-colour was just applied in order as seen in the photos

With the first mask reapplied a rattle pack off primer, high build used to lightly cover [tone down]  then the area for red was  applied and once dry the mask applied.

Particular attention was paid to the gaps that created by segmenting the decal, it is impossible to create a perfect profile match as they distort on application especially over rivets.

At this point, the Earth was applied, then Forest Green with the pattern marked out at the start using the diagrams above. All the outlines were marked using the Earth and the gun on its tightest pattern.

Comment

It is just one big learning curve

Painting Wings

Preparation

With the wings off to fit the tanks and tidy up all those small details and the decision was made to paint the underside of both in Duck Egg Green. The first task was to remove the fibreglass tops and mask up the wheel well, tips and other items requiring protection.

The wing was moved under a 6 x 3-meter gazebo, with the sides closed the wing, next, a thorough check as made and all those overclocked tasks were resolved and finally, the whole service was cleaned using water/detergent and 3M Ultra Fine sanding Pads and dried with paper towels. Both undersides were wiped using lint-free towels with wax and grease remover and wiped with the same then finally with a tack cloth.

Four [4] small blowers were mounted onto a work table to help extract fumes and overspray, it was decided to use smaller blowers as if a large set of fans were used it would mean lots of air coming in creating the need for filters.

An Apolo 5 stage turbine sprayer was selected for a number of reasons,

The first one being as I am 100% dependent on solar and thus have limited power for a large compressor. Another reason was they produce very little overspray due to the low pressures used and they warm the air helping to dry it for spraying. A  full-face mask was purchased to spray all the 2K products along with a mask/filter for the undercoats and base.

Personal Up Skilling

The internet is a good source of information but it has to be filtered, listed below were two key pieces of information that helped me make a decision to pull the trigger. Many hours were spent looking and absorbing as much information but end the end its spraying that is the final judge of all the effort.

2k paints are thinner than water, the first coat is a 'dust coat' - it means just that, dust the paint on, do not attempt to cover the whole surface with paint with the gun. Since the paint is so thin, it will spread and evenly cover the surface. For the second coat, lay it on a tiny bit thicker. It is difficult to see how thick you're putting it on though. You'll find after the dust coat has had a few minutes to settle on the panel, it will form a solid colour and the dust effect will go away. This will now give you more surface area to cover with the second coat, hence needing more paint.

[The comment above was extracted from a painting forum and proved to be of great value]

Jake LeStrada "No Fool Zone"  was a personal mine of information on using an HVLP and was the final link to give me the courage to pull the trigger.

Painting

Concept Paints 103 etch primer was thinned 1:1 using approved thinners, strained into the paint pot and after test applications on paper was ready to apply to the wing. A light coat was applied. Next,, the whole area was scuffed with a 3M Ultra Fine Sanding Pads using water with detergent, this didn't remove the paint from the rivets like 600 grit would have thought it was used in some areas. Once done the final feel was smooth so the next step was to proceed with applying base colour.

No high build primer was applied to save weight - my gamble.

Once ready the Duck Egg Green basecoat was mixed 1: 1 using thinners supplied, strained into the paint pot and after test applications onto paper the first coat was applied. Though it looked OK there was a lot of orange peel and this was traced to operator error, to fix this, it was sanded over an afternoon.

With the next application, the thinners were increased slightly and the fan width narrowed from wide open. The gun was held at an angle of about 30 - 35 degrees to the wing surface with the rear fan nearly parallel tracking the spray line and the top side blending the previous pass. resulting in a smooth glossy even finish.

Note: Doing it again I would spray lengthwise on the wing to reduce overspray

This is an entirely different task as the paint required a catalyst and is mixed in a 2:1 ratio and it is potentially dangerous. For all paint 2K operations, the builder wore a full mask with external air supply supplied by a separate compressor, this is only required for the 2K.

At locations, where covers are to be installed are masked before painting to create a clear indicator to anyone that something is missing when final assembly is complete.

Finally, 2k Satin Clear was prepared in the same way and two light coats applied.

Comment
Painting, at last, painting at last.........!! 

The front leading edge of this aircraft was riveted using countersunk pop rivets as discussed with the factory in the early days, since that time the factory has gone all dome for a number of reasons but mainly from the experience gained from multiple airframes. My efforts we a mixed success with the primary issue being dimpling in place with a hand tool, doing this again I would have dome riveted along the rib line and countersunk rivets along the stringers to remove the visual intensity that creates.

The next task will be to have the signwriter to detail the underside of the wing to reinforce that military-style theme of the project along with the roundels and will be covered in a separate blog.

Gear Doors

This blog cover the assembly and installation of the main gear doors

Main Gear Doors
The factory-supplied stiffener lighting holes were flared for appearance reasons with the inside face primed with an SLS etch primer before riveting. 

Gear Door Stiffeners

With the riveting complete a trial fit was undertaken to reveal a few issues. There was an apparent need to remove some of the stiffeners, an email to the factory showed that the updated instructions now detail this task. The Dremel was fitted with a cutting disc to remove surplus material, then cleaned using a combination of files and 240 grit wet/dry.

The cut back shown on the right was extended for additional clearance as the door stiffener was fouling on the undercarriage

The factory instructions showed an M5 threaded rod bolted through the door skin, it was decided to investigate if this could be avoided while achieving the original design intent.

After modelling, new gear door attachment brackets were prepared with the opportunity to increase the centre distance taken now allowing mounting brackets to be riveted onto the inside face of the undercarriage doors.

The material chosen was HT Polymer Plastic for its combination of strength and melting point with this product exhibiting excellent properties with most materials it could be in contact within service.

The factory-supplied M5 threaded rods were cut into suitable lengths and installed into the rod ends then secured with high strength Loctite. Aluminium angle attachments were fabricated providing mounting points for the doors.

The top bracket clips around the ring located at the end of the gear and are locked into position with a M3 screw on each side of the attachment, next, the lower bracket top side is fitted onto the gear. With the threaded rods fitted the top side, the cart was opened and the lower cap fitted and finally, the inside cap is secured as per the upper with a pair of M3 screws but left loose. 

The door is closed and the upper mount aligned to the leg to create the correct the alignment between the doors and opening. Once correct the saddle clamp at the top of the leg is secured with the M3 screws allowing the height of the door to be adjusted. This is a simple trial and error task with the M5 flange nuts adjusted to level the door, a number of tries were required but finally, it did get there.

Once level all the flanged nuts were tightened to securing the door to the leg.

The suitability will be proven in testing but it would appear that the clamps are stronger than the gear doors. The factory has a new method for mounting the doors and is worth investigation.

Comment
A lot of work to remove four [4] nuts on the outside of the doors but looks tidy. A separate blog on the brake hydraulic will be posted as soon as I can get time but for now, look me up on Facebook - G Spencer Salt

Canopy Last Jobs

This blog cover finishing the canopy.

Overview
The canopy on this aircraft has been modified in a number of ways some planed and others forced by the execution. Yes, it added a bomb in extra time so be warned.

Installation Shroud
The shroud is the most distinctive feature of Shorts T1 Tucano so this was the first extra item fabricated. While simple on the outside, the execution was a protracted task due to a lack of experience and the risk of damaging a very expensive piece of perspex. After weeks on/off of filling and sanding, the time to fit it onto the perspex and frame had arrived.

The scheme developed seemed /simple enough, the external edge was to be fitted using 18 x 1 mm double-sided automotive trim tape with the rest affixed with beads of SikaFlex Eurthane adhesive sealant. The first issue was that when dry fitted all look great but now all those little issues raised and in the end it was decided to cut the single piece shroud into four [4] pieces and then re-fit them. 

This worked well except for the last one on the starboard side and this turned into a custom fit - why? - who knows but once it was 80% done it had to be finished.

The shroud was a big job and once painted it will now have to have the edges filled as they are not as flush to the perspex as the builder would have hoped. This was caused by the mounding tape as it packed up the edge up by a1 mm and exaggerated any fabrication errors.


Once done the band across the top had to be dressed, while the initial thoughts were for a painted black band at this point something more substantial was required. 

The answer came in a roll of concrete gap foam that was glued together to form a 20 mm thick light flexible strip with the top having a series of lighting holes drilled to create a sense of importance. 

It as glued onto the canopy with a pair of 3D printed ABS covers blending it into the frame.



Handle
The kit did not include an external handle and it was decided to modify a commercial flip out but he the builder saw prices in the $250 plus range back to the CAD system. A flip-out handled was printed and installed. 

This required the cutting of a suitable hole through the side so this was done with a combination of fear and care. In the end, it was secured as planned with two [2] x M4 aluminium screws from the inside of the frame into the handle body. 

The handle will lock using a piece of fridge magnet strip fixed to the inside of the body with a screw located into the handle

Will be made available on the web site once ready for sale.


Latch Cover
One of the last issues was the latch cover through the side cover on the frame. A number of attempts to install the factory slotted stainless steel covers were tried but with deteriorating results. 

It was decided to print an ABS cover and install it covering up the gaping hole in the side cover, after a couple of tries a successful model was developed and a Marwen cover printed with instructions.

Will be made available on the web site once ready for sale.

Canopy Handles

It was decided to print handle covers for the pilots and co-pilot's canopy latch handles for comfort and eye candy. 

They were printed, painted and fixed using M4 grub screws onto the existing handles.












Will be made available on the web site once ready for sale.

Seals
There are no details on seals but it was decided to add a D seal along both of the fuselage sides of the aircraft, Using any sealing material can cause an inability to close the cockpit due to the forces required, do not be filled by how soft it feels as the forces added up quickly making a closure on the latch side impossible.

A D seal will crush easily and the one chose when flattened was the same or slightly lower than the hinges when closed. Will not airtight it should help resist airflow into the cockpit area when airborne. Goliath 15 x 10 mm self-adhesive D seals were selected then fixed using urethane adhesive to the canopy frame. It was felt that the self-adhesive tape may not have the required durability in service.

Explosive Cord
One of the key features of a Shorts T1 is the white lines created by the explosive cord used as part of there aircraft ejection systems. While these were to be painted, the builder was not 100% on board and resulted in a  better product being discovered. This was in the form of 9 x 6 mm D foam self-adhesive door seal material by Raven in Australia. 

Using photos of the Shorts T1 canopy a suitable generic scheme was developed and applied. 

The overall result idea produced a good result on the inside, this builder will have to wait for the unveiling until the painting has been completed.

Canopy Installation General
My canopy was an early model and the new aircraft have larger hinges and a ring [frame] that locates the frame to the fuselage but my issues I will outline for reference.

The first issue was the hinges these required packers to locate the frame into alignment with the frame. Once this was done the shroud was fabricated and this is covered under the category "Canopy" in this blog.

At one point the factory and this builder decided to try installing a gas strut to support the canopy when open and limits its travel, this is now done with a cable. Based on information supplied by the factory on the Brazilian Tucano the builder took up the challenge. 

After fabricating the necessary structure some real issues surfaced with the worst being that the canopy now was 6 mm out of alignment at the front this was traced to the 15 kg of thrust from the gas strut when closed and the clearance in the hinge pivots.

The original canopy was located on pins on the port side, these did not now line up and after numerous attempts at modification and redesign, they were abandoned as a lost cause, at this point, I could remove the strut or burn more time.

Not being very smart it was decided to press on. 

In the end, a roller was fitted to the frame that countered the strut and rollers added to the canopy frame at the from and rear. Bakelite button aligned the canopy as it closed at the from countering the tracking forced generated by the roller with buttons at the rear bulkhead being the last locator. Did it work? - yes - Did it burn time - Yessssss.

Final Clean Up
When applying the adhesive to secure the canopy the dread of all builders occurred - some got onto the exposed area and the time had arrived to fix it. A Novis kit consisting of Part 1,2,3 was purchased along with a sheet of 600/1200 grit wet and dry.


The affected area was sanded with the 600 and then 1200 grit in straight lines crossing at 90 degrees. Next the area was polished using the Novis #3 the #2 revealing a smooth canopy and no mess. 

Finally, the whole canopy was polished using Novis #2 and cleaned and polished with #1. 

When the painting is complete the exterior will be treated in the same manner to reveille hopefully a shiny clear canopy.
 




Comment

Based on the drama this builder has created assembling the canopy I would have the factory fit the perspex if you can afford it. If not fix the canopy using an automotive urethane adhesive sealant and do this with it installed and locked on the airframe and allow it to cure. The assembled unit is very flexible so it is the builders opinion that it would be best to not build in any distortion if possible.

The shroud was a lot of work but in the end, it makes this a Shorts T1 not just a Tucano.

Why are these things not as simple as our dreams -eh?

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...!