There’s something rather satisfying about the first time it all comes together, wings, fuse, legs, and tail feathers, and pinning the control surfaces on. Pre-covering photos seem to be a bit of a tradition:

I covered the wings in Diacov 1000 from Sarik Hobbies which is an “Extra-lightweight iron-on polyester fabric” probably rather like Solartex or Oratex but I’d never used one of those so it was all rather new to me. It cost £33 for 3 metres by 73cm which John says is expensive but I must say it goes on like a dream. Just stretchy enough to wrap around compound curves when warm but adds tremendous rigidity after cooling, shrinks perfectly and looks great. Slightly translucent and slightly more so when varnished. I used polyurethane spray for the wings and brushed on the tail. Spray looks much better.

I cut the signwriting out of film covering and ironed it on before varnishing. Adhesion was really good.

For the fuselage I used cheap-as-chips transparent dark purple from Ali Express. The roll arrived damaged and their customer service was rubbish but enough of the film was useable and the value for money was great. Covering the stringers was probably the most challenging film covering I’ve ever attempted – curves galore.

I’m hoping that Winnie the Pooh turns out to be a good pilot. Apparently he’s had quite a bit of practice flying balloons with Piglet.

Installing the radio gear was pretty uneventful but the lightweight snakes I’d bought from SLEC weren’t up to the job at all. In the very short distance between the tube ends and the control horns they bent all over the place so I had to use piano wire instead. Fortunately the runs were fairly straight and the wire quite light.

On advice from model designer Peter Miller I went for zero angle of attack, zero tailplane angle, and zero down thrust. Although I did add a bit of right thrust and because of the high wing I have a sneaky feeling I will have to add quite a bit of down thrust so the removable cowl will probably need modifying – pretty easy.

The entire motor set up, the servos, and u/c hardware came from George at 4-max who provided great service and advice. SLEC provided great balsa and plywood. Thanks also go to John Harvey for encouragement and Cliff Harvey for inspiration and tips – particularly on laminating balsa curves, and Martin Tonkins for motor chat.

So there we are, my first vintage model. But in truth, of course. Although she looks old. She has no vintage whatsoever. In fact, she’s nothing but an Old Phoney.

POST-MAIDEN UPDATE

Turns out the u/c legs weren’t up to the job so I made a more substantial pair. The wire braces still broke so I switched over to using bowden cable and steel springs – seems to be fine now.

Test flights are going well. I’ve added down thrust and mixed elevator with the throttle. Her speed range is impressive from fast enough right down to extremely slow. Even with full down flaps and holding in full up elevator she doesn’t seem to stall, certainly doesn’t drop a wing anyway. Shortest landing roll I’ve managed was 3 metres in still air.

Just as the wing was my first without span-wise sheeting – this is my first fuselage without sheet sides. But, as it turns out, there’s something rather satisfying about longerons, stringers, and all the fiddly bits in between.  And when you’re REALLY enjoying a build, anything that makes it take longer just means the pleasure lasts longer.

What are they called? Those curved bits that hold stringers in place? I have no idea but they seemed like a good place to start. Cut out of balsa they’d be bound to split, and terribly weak, so I cut the shapes out of 1/64” ply then glued 1/16” balsa copies either side but with the grain in opposing directions. Light, stiff, and strong.

Next job was to cut out the 1/32” ply doublers. I copied their rather weird outline using the old ‘pin prick’ method. I remember being 13 and getting into terrible trouble for doing that in a school woodwork lesson. “But it works so well” I exclaimed. The teacher wasn’t convinced. Evidently it was not ‘the done thing’. Cutting them out with a scalpel was a bit hard on the fingers but it gives such a clean cut compared to the scroll saw or fret saw:

(The weird bit sticking out above the cabin is because I’d not yet decided how to build that part – just leaving my options open).

Because the longerons had to be ¼” square, but hard balsa and very curved, I laminated two 1/8” x ¼” strips instead. (the ‘Cliff Harvey effect’ again). With the help of a weak solution of household ammonia (to loosen the wood fibres) they bent quite easily and were glued after drying:

All the fiddly bits went together well with soft ¼” sheet infills at the front:

Whilst making the formers I had the idea of incorporating a tow release which I incorporated into F3 so the mechanism terminated just behind the wing:

The cabin top was a bit of a challenge.
I don’t like the look of wing bands that go to a dowel below the cabin so the cabin top needed to be strong enough to cope with pulling quite a bit of G force without the front wing dowels giving way. I tested the strength of a 15mm projection of 6mm dowel by sticking it in the vice hanging a 12kg weight off it. It didn’t break. But whatever they were glued to needed to be equally strong. But the shape was complicated. Hmm…
In the end I carved and sanded a block of 12mm birch ply to shape. It’s curved in two directions; top view to match the screen wrap-around; side view to match the airfoil; and V-shaped in the front view (to match the wing dihedral) and epoxied to three layers of 1/16″ ply on each side, all just 6mm thick:

The diagonal bracing and turtle deck stringers were most satisfying…and making the battery hatch and removable cowl: Almost ready for covering!

I um’d and ar’d over how to hinge the flaperons and eventually decide not to – to just let the film be the hinge. Multi-tasking was never my strong point so rather than try and wing-cover and hinge all in one go I decided to top-hinge the flaperons with a narrow strip of film first, I also covered the fuselage fairings before the whole wing:

Covering went well. The wing and tail undersides are dark blue. I was surprised to find that the cheap white Hobbyking went on better than the expensive dark blue Oracover. The winglets had 2 coats of sanding sealer, 2 of white enamel, and 2 of red:

The radio installation had been planned for from the outset so seeing it all fit – and the servo slide working –  was all very satisfying. Working out all the angles to achieve ‘more up than down’ was fun too:

The flaperon horns needed to sweep forward:…and the elevator horn had to sweep backwards to be 90 degrees to the control cable:

I was pretty pleased with my first attempt at signwriting with Oracover after asking for advice on the Model Flying Forum.

Close-up of my first attempt at function mixing with a sliding servo:

The wing-mounted fuselage fairings hold the wing halves together:

And the finished model – the DR 420 –  ready for her first test flight. She balanced at 1/3 of her root chord without any ballast needed – pure luck!

Since I left the hobby around 1980, glider fuselages seem to have been on a diet – so many these days have extremely spindly bodies with hardly a curve in sight. I must concede, though, that the word ‘fuselage’ does in fact come from the French word fuseler meaning ‘shape into a spindle’. I’m sorry folks but spindly long-thin-stick fuselages just don’t do it for me AND they’re exactly the opposite of what you need for knife-edge flying and slow rolls.

First job was to cut out the 1/8^”  sides, 1mm doublers, and F1 through to F9. As I don’t have a jig and the fuse was deep and narrow I decided to stick all the formers to one side first before bending the two sides together. Each former had to meet the side at a different angle so each was temporarily held by a bespoke scrap of balsa.

When side two was added I used sash clamps to hold it all straight but it didn’t work well so I think I’ll make some sort of fuse jig for the next one. Any tips?

Before adding the bottom sheeting I put her back in the clamps to try and correct a slightly twisted nose. That worked a bit but I still had to add some balsa to correct it. I then found a slight bend at the tail end! Bit of a pain but not beyond correction later. I really must make a jig.

Then came the top sheeting, nose block, and canopy fashioned from as many scraps of soft 3/8^”  as I could find. I’d used ½” triangular section all along the top and bottom so I could do lots of rounding off the corners. After lots of work with the palm sander her rather pleasing shape emerged at last.

So here she is, temporarily pinned together in all her naked glory with, (as Kryten once said in Red Dwarf), “all her in and outy bits going all iny and outy”. Not a spindle in sight.
Happy Christmas everyone.

I decided to try dyeing the balsa before covering with translucent film and chose pale pink to complement the ‘heather’ pink Solarfilm I’d bought for the underside.

I should have known that pink and yellow makes orange. Will orange and pink really GO together??

Rather than use plastic hinges I thought stitching might be nice.

After covering I dropped the radio gear in and discovered to my surprise that my little 4-cell NiMH battery was too heavy for the nose so it had to go above the switch in the fuse top.

Here’s the radio installation (plus the 2 flaperon servos in the wings). The nose is completely empty!

I avoided unsightly bands going over the fuselage top by adding a (sort of) 3^rd wing dowel – so some of the wing bands also hold the top on.

For the finishing touch I simply taped a strip of film to the cutting board, taped a paper print of the word ‘mediator’ over the top, and cut through with a scalpel.

Bottoms up!

Finished weight under 850g/30oz. Wing loading only 9.5 oz/sq’ which is less than my Kloudrider!

For inspiration: thanks to George Aldrich (Peacemaker) and Steve Lange (Le Fish).

An electric palm sander is a wonderful thing! If only I’d had one in the 70’s I could have filled the whole bungalow with balsa dust rather than just my little bedroom. Oh and the wonderful smell of cellulose dope… those were the days. And mixing my own diesel fuel… I regularly bought Amyl Nitrite and Ether over the counter in the chemist at just 15 years old! Anyway, back to the build…

After quite a lot of sanding:

Adding the fuselage fairings to the wing roots:

Then the wings had their final sand:

What you can’t quite see behind the winglets is, what was going to be the outer 4 cm of flaperon is now a short section of trailing edge with built-in washout. Will that prevent the nasty tip-stalls I’ve been warned about? We’ll have to wait and see.

To help achieve ‘more up than down’, the flaperons needed horns that were raked forwards. I couldn’t find any for sale so made my own using bits of plastic from an old bucket:

So here she is with her control surfaces pinned on just for the photo…

Hello DSSC.
I thought you might be interested to see my new slope soarer design which carries on from where I left the hobby in 1980. The repeated design/build/fly/crash, design/build/fly… cycle which dominated much of my spare time in the 70’s, culminated in this rugged 2-channel model I still have 40 years later.

My own design from the seventies

My new design uses the same boxy fuselage construction – full length thin ply sides, soft 1/4″ balsa top and bottom – but instead of 1/16″ all-sheeted wings I’ve copied the open-frame Kloudrider wing construction but with a semi-symmetrical section and higher aspect ratio.

I’ve designed things with ailerons in the past but not flaps. I rather fancied doing both this time but I’ve never really understood why control surface movements try to make different parts of the wing behave in different ways at the same time. So, I decided to go for full length flaperons (which I’ve also never done before) and to try the old ‘sliding servo’ way of mixing the controls which I heard about in the 70’s but never tried.

(By now you’ll have worked out that I’m some kind of weird old-timer who doesn’t want a foamie, doesn’t like programming, but does like a challenge!). “No wonder they used to crash” I hear you say.

The fuselage shape is influenced by the ASW 15 and 17 but I also like the way the 28 is concave on the underside of the fuselage. I also fancied having a go at a T-tail as I’ve never done one of those either. Oh and those little winglet things too – they look like fun. I decided to make the front end pretty big so I can get all four servos in and still have plenty of room for my fingers which don’t work as well as they used to. Anyway, that’s enough waffle for now. Here’s my hand-drawn plan which I’ve already deviated from slightly…  (more in the next post):

My new design

David