DeHavilland DH90 Dragonfly

[Steve Rickett 2333]

The first 'final version' cowl is now out the moulds. I've started trimming it to fit but not fixed it into place yet.

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The hinge was obtained from Phil at Fighteraces and does a great job. At the moment I have used Mick Reeves's tiny counter sunk screws to hold it in place. I may have to rethink this... does anyone know of some ultra tiny countersunk screws and nuts about M1-M1.5 mm? Modelfixings are my favourite spot, but they dont have any that small.

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[Steve Rickett 2333]

I have finished off the basic fabric covering on the wings and control surfaces. The smaller parts where a bit of a fiddle, but clothes pegs helped to keep the fabric in place until the cement grabbed (30 secs). I quite like knowing that the fabric has been applied to scale too!

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On the recommendation of Ian Turney-White I gave Randolph Aircraft Products' Dope a try. It is a Non Tautening Nitrate Dope, though I didn't realise it had a green dye in it!! It won't hurt the final finish and does allow you to see where you have been, even if it looks a little funny. You can get it from LAS Aerospace in Okehampton.

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The first coat or two should be thinned (Approx 50% thinners) and brushed on. This helps to fill the weave and get the dope through the fabric. I have given one coat for now, then I'll add the rib stitching and give it one more brushed cost before one or two coats sprayed on with a spray gun.

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[Nigel Cox]

Would these be of use for the hinge screws http://www.ebay.co.uk/itm/161335189590? ... EBIDX%3AIT ??

[paul needham]

or try here..... http://tinyurl.com/pnfmj5k

[Steve Rickett 2333]

Thanks Nigel, Paul.

I have just secured some from Macc Model Engineers!

[Alan Bithrey]

Lovely build Steve of a fantastic aeroplane (as it's a DH I might be a bit biased!)

I have recently started doing a few bits to a Flair Tiger Moth including hinging one of the side cheeks of the cowl using miniature piano hinge.

I didn't want to drill holes in the cowl so near the edge so I went for "Epoxy Rivets". In essence, I've drilled lots more holes in the hinge flanges then bonded them to the cowl making sure:

a) the epoxy completely filled each hole
b) I didn't glue up the hinge

Then used some glass fibre tape bonded over the top of the flanges to sandwich the flange.

Full details on my thread on RCMF if you want to take a look

http://www.rcmf.co.uk/4um/refurbs-repai ... msg1213024

Might be of interest.

Alan

[Alan Cantwell 1131]

Steve, go to a local opicians, Thats what we actually did at work, but there are these,
http://www.ebay.co.uk/itm/1000Pcs-Micro ... 1407896644

Lovely build by the best out there, looking great, and, erm, that green tint, Whats that on the tin say? Ya muppet, Cant wait for the elusive never modelled next project, Fantastic!

[Steve Rickett 2333]

Thanks guys. I'm all sorted for screws now!

Ha, yes it says it on the tin, but not on the description on the Website!! It'll make no difference to the finish!

[Steve Rickett 2333]

I made a start on the rib tapes the other day. I think this is a common system for making rib tapes and certainly not my idea, it is very good though. A basic jig is made using pins, or nails into a flat board. Lay a sheet of paper, not too thick, and wrap your chosen string, cotton whatever around the pins in a zag zag fashion. Then apply 2-3 coats of dope to seal the string to the paper. When dry, you can cut into strips.

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I stick 'em on with dope too.

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Mick Reeves pinked tapes cover the stitches. These are 1/4 scale which make the tapes about 1/2" wide. A shade too small for the Dragonfly at 1/3.5 scale but it is cheaper than getting them cut specially!

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When I was doping the string to the paper in the jig I though the string looked a bit too thick.......but I carried on. When I was applying the strips to the model I thought they were a bit too big....but I carried on. When I finally realised that the wing stitch spacing was wrong I could go any further......so it all had to come off!

[Steve Rickett 2333]

Hopefully this looks a little bit better!

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[Steve Rickett 2333]

In between playing around with rib tapes, I have been slowly getting the large 'trousers' mounted. Quite a tricky affair, but I think I am about there now.

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I'll need to look at baffles next, but should be plenty of cooling.

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I have made some catches for the opening hatches. Similar to the full size (I admit they are not 100% in the interests of usability). Telescopic sections of brass tube with a spring...
You can also see the 2 (four per spat) bolts holding the rear section in place. I'll replace these with domed bolts when I can.

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1 quarter turn allows the fastener to release... (Note the two rivets to hold the catch closed)

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...and easy access to fueling ports, charging jacks and the carb needles.

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I'm sorry, but I didnt take any photos while building these (I was enjoying it too much to stop!) There is a main brass tube shaft with the domed section slotted and soldered in. A telescopic section of brass is fixed into the wooden support, spring added and then a telescopic section of brass soldered on to seal the unit up......

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You can make out the blind nuts for the holding the front section in place....5 bolts here.

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As per the real thing, a support for the top of the cowl made out of brass sheet. It is slightly off centre to avoid interfering with the cowl hinge...it doesn't look so obvious in real life!

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[David Brown]

Fantastic detail Steve, I am enjoying watching your build.

Dave

[Steve Rickett 2333]

Thanks Dave,

It's always nice to know everyone is enjoying reading it.

That's all I'll get done in August...what with a busy work roster, Elvington and Winterton show and then a two week family holiday....things will resume in Sept!

[Steve Rickett 2333]

Over the past few weeks I have managed to go the last of the rib tapes applied and the final coats of dope on.

In total, over the Diatex, I have 2 coats of dope brushed on and 3 coats sprayed on. The weave is mostly filled (more importantly there are no pin holes) and the fabric is drum tight and warp free with using non-shrinking dope.

It's looking a little bit green at the moment though!

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[Steve Rickett 2333]

In order to finish off the fuselage sheeting I need to get the cockpit and cabin detailing done. I have decided to fit out the whole cabin as best I can because those windows are so large I would rather not just see balsa in there!

First up is the upper sides of the cabin. On the full size these are clad in a felt/carpet type material. I found something that I think works from a dolls house suppliers which comes in ft sq sheets and is self adhesive too.

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[Steve Rickett 2333]

The lower side walls of the full size are lined in leather. I thought long and hard about how best to replicate leather, but none of my ideas were really going to work well enough! Thee was only one thing for it...leather.

I found a company called Pittards who sell leather hides in all kinds of grades, thicknesses and colours. Luckily they had a close match of grey I was after and in extra thin too! In total I'm probably going to use 3 of these hides which are about 3 -4 sqft each.

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[Steve Rickett 2333]

I first used card strips to build an outline of the side wall to be lined in leather.

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And then used this pattern to cut out a thin card stiffening plate and the leather. The leather is cut about 1/2" oversized.

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I then used an automotive fabric trim adhesive which is applied to both the card and leather.

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Then it's a really easy job to lay the card onto the leather and fold the edges over.....

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And in situ....

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[Matt Harrowven]

Very nice Steve, and thanks for taking the time to type up how-to / explanations. I think I'll felt and leather the cockpit of my next warbird just to have a go ! :-)

[David Quartermaine]

Hello Steve,
Thanks for the Pittards lead, thought to try some for an SE5a cockpit combing and headrest. Arrived this morning looks very promising much better than the vinyl type stuff I had put by i.e. very thin, soft and pliable with a lovely tan brown colour.

Dave.

[Steve Rickett 2333]

Thanks Matt...You could always do an 'Executive fit' Spitfire next?

Thanks David, I hope it works out for you!