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DH86 Refurbishment


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Thanks for the comments, its good to know someone is reading this stuff!

The model could be described as mutton dressed as lamb. Its 25 years old and though much repair and rework has been done, its still an old aeroplane, that's obvious as soon as you look beneath the surface.

The goal is to get it into the air again and looking quite different from the drab impressed-into-service scheme it wore before. The finish will be a fictitious one inspired by (that's a modern euphemism for unimaginative copying) the final scheme of the Hampshire Aeroclub aircraft G-ACZP, pictured earlier. However I thought I'd modify it to resemble the first operator of G-ACZP which was Jersey Airways.

One of the problems I've given myself is getting the registration to look similar to the 1930's standard British lettering. None of the Microsoft fonts come close so it will be a case of designing the letters from scratch. The plan is to use G-ACXC which was the nearest registration to G-ACZP never put on an aircraft. It was originally issued in a batch for Cierva C30 autogyros, which weren't completed. G-ACXC is really only three letters - the G being a simple horizontal bar to a C so producing them should not be too much trouble. As the fuselage colours of red and white have their interface near the centreline with the letters superimposed, I thought that juxtaposed colours (red on white and white on red) fashionable at the time, would be an added interest.....all this is to play with in the next few weeks.        

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Hi John,

 

5 hours ago, John Rickett 102 said:

Thanks for that Brian, Have our paths crossed in the past?


Mostly earlier on in this thread, I’m part way through building a Rapide from the Martin Tuck plan and you kindly sent me a couple of lenses for the landing light.

 

However I did see the DH86 fly some years ago, it would have been at a show somewhere.

 

You also showed it to me when I came to your house to buy one of your models. A Chiltern Models Sea Fury. A long time ago though!

 

Brian.

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I'm a lurker on this thread John but don't contribute as my skill and knowledge base for this type of build is way below what yourself and others have clearly demonstrated. However, I find the thread both inspirational and educational so I hope you can draw some sustenance from the knowledge that your efforts are not going entirely unheeded!

 

 

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4 minutes ago, Stephen Belshaw said:

but don't contribute as my skill and knowledge base for this type of build is way below what yourself and others have clearly demonstrated.

Mr B, I have just checked out the dummy engine you have produced for the T31. It clearly shows the statement above to be a porkie pie!

 

John, I too lurk and get inspired. But I really don't have the skills!

 

Great work, both of you...

 

Graham

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Thank you for the kind comments, and I agree the T31 engine is a little work of art, well done.

 

The tail section has been rubbed down as best I can. Its fairly easy on the sheeted parts, not at all easy on the open fabric areas. I wanted to get rid of as much dead weight as possible although I think its probably a waste of effort, the amount of paint that can realistically be removed is minimal. 

 

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The whole model has now been given a coat of 2K primer. When I started this job I thought that the tail was good enough not to require recovering so I'd just have to get round painting with the rudder and elevators in situ but perhaps not recovering was the wrong decision as the primer has shown up some damaged bits... I'll live with it. 

 

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Each engine bay has now had a coat of primer and a grey 2K topcoat. If this doesn't make a barrier to the fuel, I'm giving up and trying flat field soaring. 

 

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The engine bays are not particularly pretty but better than before.

 

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Looking rather drab even in the afternoon sun and recuperating from a mini disaster - the wind blew the fuselage off the trestle. Not much damage, just a puncture in the covering underneath but annoying nonetheless.

 

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A small patch was applied, and given a couple of coats of dope followed by some !k filler.

 

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With a bit of luck it will hardly be visible once the topcoat is on.

 

Before the final coat can be put on, there are two little problems to solve. The first is to reduce the gloss of the paint to better match painted fabric. The second is to decide where the cheat lines should be and where the fuselage registration letters should be positioned on the cheat lines, so a bit of experimenting was called for.

 

An old test panel was rubbed down, given a coat of primer and then a topcoat of the white; actually its not white, its the lightest shade of grey I could get mixed. I prefer this as it looks less stark than brilliant white.

 

The lower part was then painted with matting agent added. The data sheet said to use it at a ratio of 1:2, though to me it looks too matt for the purpose. I'll try reducing the ratio next time.

 

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 Once the correct degree of matt is arrived at, the plan is to use the test panel to see how well the lettering masks will adhere to a matt finish and whether there is any paint bleed under the masks.      

 

 

 

 

 

 

 

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Most motor factors can mix paint to a satin finish which is still quite glossy, too shiny for a warbird type but a fair representation of a scaled down gloss finish.  Too be fair it does look much like the lower section of your test piece.  Its perhaps a better place to start than with full gloss paint?

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Thanks for the information Stu, I do buy the paints from a motor factor - Humberside Paints. They have suggested they can mix it but first I've got to determine the degree of sheen required. Once that's found I will probably get them to mix it so as to maintain consistency. The disadvantage of premixing is its expensive and the unused paint will always be matt.

In the past I've used whatever paint I could find in the colour I wanted, regardless of gloss, matt or satin, and then given the whole model a coat of KlassKote clear to bring all the sheens to the same consistency and to act as the fuel proofer. That works for so long but inevitably the fuel will find an edge and attack the paint below, also some paints are attacked immediately by the solvents if they haven't had sufficient drying time (which can be weeks) so for the past few years I've been using 2K paints and primer and trying to reduce the gloss by applying the paint 'dry'. Not being a proficient sprayer means the results have been inconsistent so this time I thought the matting paste approach might work.                   

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With the test panel being curved its impossible to catch the light for all test strips but having now tried mixtures at 25%, 33% and 50%, I think 33% is the nearest to the desired effect but perhaps could stand a little more gloss, not as glossy as 25% though.

 

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I'll rub down the whole panel and apply a 30% mixture before trying lettering on it.

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Painting the test panel proved to be a frustrating experience. I think anything that could go wrong did, but at least it was better to practice on the panel rather than to commit straight to the airframe.

 

For a start the black borders are too small at 1mm and don’t provide enough emphasis to the letters, these are 110mm so that’s a less than 1% border. I’d experimented with the dash with a thicker border (2mm) which looks better although I think 2.5mm will be better still. Also, in some places the thin border didn’t adhere sufficiently to the paint below and consequently lifted when the masks were removed. This may be partly due to there been so little surface area to gain adhesion.

There is quite a lot of paint bleed and this on a smooth panel so undoubtably it would be worse on a textured surface. I’ll have to pay greater attention to making sure the masks and any tape are well pressed down.

 

I hadn’t rubbed down the paint to provide a key as it would have meant that some of the finished white would have shown the scratch marks of keying, and neither did I clean with panel wipe so there could have been greasy finger marks which prevented the masks and paint from adhering.      

 

In painting the juxtaposed colours, starting with a white background, the red letters have to be re-masked in order to spray the black border – getting the masks into a precise position was incredibly difficult. At this point everything is red so there is only the raised edge of the adjacent mask to work to. Increasing the width of the borders will make any location errors less obvious.

 

Another problem is gauging when to remove the masks, too early and the wet paint flows slightly, later when the paint is dryish but tacky, it tends to leave string marks when lifted. If it’s left to be touch dry there is an edge which doesn’t smooth out. The last leaves the cleanest finish but unless there’s going to be a final clear coat, the paint can’t be rubbed down due to the unsightly marks that remain.   

 

It would have been much easier to just paint black letters but the good news is I like the effect and think it provides a period look. As an additional experiment I’m trying one of the wing (black) letters to see what that looks like with a red border, It’s worth persevering, at least for a little while.

 

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Thanks for the support Manish, but I'm not happy with the result, there are bits of black border missing in quite a few places. I've learned a few lessons which is what this hobby is about so hopefully the next attempt will be better.

Jersey Airways Ltd, now mostly obliterated with the latest mask was a success so I'll use those masks without alteration, but then one colour is quite easy, its trying to do multiple colours where one mask has to overlay another when the errors creep in.

People say that you can't see any of it when its in the air, which is true, but all models spend most of the time on the ground and with the eye being naturally attracted to detail the little bits ought to pass muster. If at first you don't succeed......       

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  • 2 weeks later...

After rubbing down again and repainting with the white basecoat, another attempt was made.

 

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This time I thought I would try one of each size of letter and see what the wing letters would look like with a red border. I wasn't keen on the result, the paint had lifted again when I tried to remove the mask, probably because I tried to remove it too early so I left it for a day and then the rest of it came away ok. Also I didn't really like the border so will paint the wing letters black only, it will certainly save on the two stage painting process.

 

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The fuselage letter I was satisfied with this time though there are small areas where the re-masking wasn't exactly right which has left some white bits, if this happens again it can be touched up with a airbrush or very small paint brush. I made the mistake of not removing the mask from the top half of the G bar, note to self 'don't make that mistake on the fuselage side'!

 

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All of the white areas have now been painted, including the wings, so as soon as the weather improves to allow painting, the red will start to go on.

 

I was hoping to have the model ready for the LMA static event at Cosford next weekend but I'm sure now it won't be complete, however the events which were previously held at Gaydon and this one replaces, were supposed to be a work in progress show, so I'll take it anyway.     

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With the weather forecast as it is, there's not much chance of any painting but progress can be made with the rigging.

With the wing joiners only being short lengths of piano wire, the rigging forms an essential part of the structure. All the flying and landing wires are made up from Mick Reeves supplied items with each flat wire consisting of a left and right hand clevis. Short lengths of stud are provided which have to be silver soldered (butted) to the stainless steel rigging wires.

 

The advantage with this system is that once complete, the clevises do not have to be removed from the model, the flying wires can be screwed in or out to assemble or disassemble the model - it saves having to work on your knees at the field with tiny screws to contend with. If you are going to use this system make sure you threadlock the 2mm screws which attach the clevis to the anchor otherwise some of them are bound to fall out.

 

Silver soldering the flat wires to a stud is not difficult but with each stud being M2, they are quite fiddly so its best if you have three hands, unfortunately perhaps I was not born that way so I had to devise a way to hold everything together based on the use of two vices.

First, using a small square file, make a vee notch in the end of the stud, this will keep the wire central while soldering.

 

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I use a length of brass tubing which has been tapped M2 left hand thread at one end and right hand thread at the other. The stud is screwed into the tube a few turns and then the tube is clamped in a vice. A length of silicon fuel tube slipped over the brass tube minimises heat loss. The wire is then pushed into the vee notch and held in position using the second (mini) vice.
The screws holding the mini-vice are not fully tightened so that a degree of adjustment can be achieved to make sure all is straight. After that apply a dab of flux top and bottom and then heat with a blow lamp using the lowest possible amount of heat.

 

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The idea is to get the joint just turning red, at which point the silver solder can be applied and a bit more heat (moving the lamp slightly closer to the workpiece) should see the solder flow over both the wire and the first few threads.

 

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Once cooled the joint can be cleaned up, I use a Dremel drill with a rotary stone attachment to flare any excess solder and to polish a finish.

 

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Two wires done today, only another 7 pairs to go....plus the tail bits.

 

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Edited by John Rickett 102
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  • 3 weeks later...

Some respite in the gloomy weather allowed the red to be applied to the bottom half of the fuselage. The paint was left to cure for two days before removing the letter borders and I'm now satisfied with the result.

I gave up on the idea of re-applying those parts of the masks removed prior to painting as they inevitably stretch a bit so cannot be repositioned exactly. I'll run off a second set and then overlay those parts that need to be covered up again to enable the black to go on - it will be interesting to see if the masks can be repositioned perfectly.............

In painting with matting agent added, I've discovered that the paint needs to be applied absolutely consistently otherwise there are differences in the finished results. If for example one area is given more coats or applied wetter, the matting effect is substantially reduced, unfortunately that's what I've ended up with in places. Oh well, that's life.

I think one of the endearing aspects of the hobby is the unrealistic expectation that the next model is always going to be an improvement on the previous!  

 

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