The free plan model in the October issue was my Bloody Mary period airliner. In this article I'll just go over some of the final details that I added and that I hope you'll agree, give the model a little character!
SUPPLEMENTARY EXHAUST
Before covering in the fuselage framework, you will need to decide whether you want to build in the prototype's secondary exhaust system. I mated this to a Special Edition Irvine 53 with standard silencer. The advantages of it are a novel, more scale appearance and a deeper and more realistic exhaust note. Believe it or not, the engines (very powerful) performance appears to be affected not in the least! Nor is it hard to make – I have no special metal-working tools nor skills. Liquid Steel or similar suffice to hold it together at the lower temperatures experienced at this stage. All you need is about 6" of 3/4 to1" aluminium tube, two plumbing elbows to fit, two lengths of wriggly exhaust pipe, an inch of aluminium tube to match the size of the outlet tube on the engine's silencer, and a couple of inches of silicone tube to connect the two systems.
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Temporarily locate the engine in position with the silencer pipe redirected inwards (but clearing the fuel tank), and make a hole in the floor for the connecting pipework. Drill a hole in the second chamber for the smaller, linking tube and bond in place. When set, ease it into position. Do not yet fit the elbows, but mark on the plan where the holes must be made once the fuselage sides are fitted.
I should also mention here that, by releasing a screw, I swung the bracket that holds this Irvine's rear needle valve so that it cleared the longeron. On reflection, reinforcement around any holed longeron might be better!
COCKPIT – OPEN FOR INSPECTION
Before fitting out, make the plate to accommodate the throttle servo. Make sure that the horn will clear the cockpit floor and ladder, and that the snake will clear the fuel tank. Do not forget to secure the outer tube of the snake firmly to bulkheads F2 and F4 or it will suffer the bends and provide negligible throttle response. Then form and epoxy in place the U-bent aluminium slot that will locate the top of the instrument panel.
Cut the cockpit floor out of 2mm ply (or thereabouts), adding a 1" balsa skirting around the well, and the strip of 1/4" sq. to give the ladder screws a purchase.
The pilots' seats are made from 1mm card. Scoring will help make neat folds for the sides and back. The seatbelts can either be made out of leather strips with a Velcro buckle, or a single strip of knicker elastic both are secured under the seat with impact glue. Finally, add small squares of Velcro on seat bottoms and cockpit floor.
I made the pilots' bodies out of light and crude balsa frames, lightly padded with cotton wool, then covered with crepe paper. The heads with helmets I carved out of balsa, but modelling with clay might be easier. The hands are paper, strengthened underneath with plastic wood. Then I applied matt Humbrol and matt fuel-proofer.
The instrument panel is made up from four pieces – the highly varnished fascia with instrument holes cut out, transparent material, impressions of dials and card backing. The control wheels are modified 35mm film container lids, the switches are modified brass drawing pins.
The balsa ladder plays an important part in holding everything together, and the sequence is as follows:- Insert the rear of the floor into its slots and push down on to the front support. Ease the instrument panel into its top slot, then swing down to secure front of floor. Tuck the foot of the ladder under front wing support tube, swing top over to floor and screw down.
With gentle heat, pre-bend the ends of the windscreen into the required curve. Fix the frame with miniature nuts and bolts. Line up on the fuselage and mark where holes will be required. Stick scrap or filler under these hole positions to give ample screw purchase. Screw in place.
A VERITABLE FLYING SALOON!
Cut the window transparencies so that there is plenty of hidden gluing area. Check that the glue you use really will grip both plastic and wood and secure in place. Using then, coloured card, trim cabin to taste.
The wickerwork seats may require some improvisation. I was able to buy a very cheap little nest of bread baskets from our local houseware shop. I first secured the divisions of the segments with white glue, then cut apart with a saw. Strips of pre-bent hardwood were glued on to hold the backs in shape, and a simple frame and legs stuck on underneath.
The cabin floor is made out of foamboard, in two sections for ease of insertion and removal. Note on the plan the built-up foamboard columns and Velcro patches to hold it in the right place. As they may vary in dimensions, number each chair and mark where the legs will sit on the floor. Cut out the little slots accordingly, and block them off underneath with card. Cut out the little slots for the knicker elastic seat belts. Insert the seats, insert the belts and fasten underneath just tightly enough to hold the seats down. When you get round to doing the passengers, the belts will hold them down too.
LEVERS AND PULLEYS
See the plan for the make-up of the tail struts. Use high-strength epoxy to glue on the ends, and use a further dab on the wood screws when you fix them in place. So that they fit precisely, apply glue to ends of wing struts (bent as needed to lie flat on wing surface and fuselage surface, and secure in situ on assembled model to set. Add lithoplate fairing afterwards.
The closed-loop lines to the rudders and elevator may look like a cat's cradle but are easy to fit and work well. With the elevator lines, note that a small guide will be required under the tailplane leading edge. With the rudder lines, note that the adjustable clevis must be built into all three sections. Also, you will have to insert guide tubes through the fins. And do not be tempted to leave out the shock-absorbing springs in the tailwheel steering circuit!
The splendid American style lettering was specially made for me by Amberley Signs, and Geoff Sparey is standing by to take your orders too on 01252 836436. The lettering is strongly self-adhesive and totally fuel-proof.
LEGGING IT
The main undercarriage is unusual in using a forward swing link system, being the only simple method I could devise to fit within the trousers. Possible tuck-under tendencies are prevented by button cord retaining straps, and even our bumpy field has caused no problems. The undercarriage frame consists of three components – the main leg (4mm), and the upper and lower supports (2.2mm ‘ish) for the coil spring. Short sections of wooden dowel locate the springs on these supports. But I hope the plan and photographs show more clearly than words how the undercarriage is made up.
The coil springs I procured proved too soft, but I was able to stiffen them up with an insert of rubber tyre mending 'bar'. You may well be able to get precisely the right size and strength of spring by contacting Lee Springs, Latimer Road, Wokingham, Berks RG41 2WA
The tailwheel is straightforwared except for the need to secure a nylon tiller above the fuselage to take the steering wires. I used a trimmed servo horn fixed to the leg with a collet (screwed to a 'flat') drilled to take a brass wire locating arm.
THAT STRADIVARIUS LOOK
The prototype's fuselage was clad entirely in the heavier and cheaper Liteply. Yes, you can obtain sufficiently large sheets to do the sides in one piece, from the more dedicated model shops. By careful jiggling, I managed to accommodate the lot on two such sheets. Expensive? Yes, but the result is strong, light and rich in character. When cutting out the panels, use a steel ruler and very sharp knife. Cutting them a few millimetres oversize and trimming to fit later could avoid annoying gaps at joints. Anyway, check measurements of panels on model before you cut. Try not to overrun the cuts, as any groove will fill with varnish and look like a dark line – practically impossible to correct. I used Dulux Woodsheen Mahogany, which is fuelproof and I pre-painted the panels for ease of application and smoothness of wet-and-dry sanding between the five coats.
Before sticking on the panels, thoroughly fuel-proof all forward areas in the fuselage that will become inaccessible once they are on. Similarly, fuel-proof the inner faces of the panels that might become vulnerable to fuel leakage. Scrape away any excess where the glue must grip the wood direct.
As it will take several minutes to spread the glue and manoeuvre the panels into precisely the right position, use a slow-drying glue or epoxy. Do the side panels first, one at a time, using tape, weights and clips to make sure that all glued surfaces are fully in contact. Similarly for the bottom panels. Now, temporarily tape the cabin top in position. The curved, top panels will be slightly more difficult to secure. I suggest you first glue the panels at one side only to the base longerons (having previously checked that they will wrap across satisfactorily), clamp and allow the glue to set. Then apply the remainder of the glue, pull across tightly and fix down with strips of tape and long rubber bands. Where there are any 'lift offs', pack in under the retainers with scrap. Before the glue is fully set, check that all is smooth and shipshape.
The engine cowlings and undercarriage fairings were cut out of lithoplate (approx. .02mm). I cut out the cowl louvres with wide and narrow chissels, a hammer and modelling knife, and would just say that I would be grateful if anybody knows a quicker way for the amateur builder!
That's it. To be honest Bloody Mary is there for you to do your own thing. You've got the bare bones so let your imagination run wild!
