The Fizza plan can be purchased at www.myhobbystore.com
ANSWERING THE CRITICS
With the Fizza, then, I hope that I've come up with a way of making the flat sheet wing attractive to everyone, and introduced an alternative method of aileron operation without compromising the design. Talking of compromise, I should emphasise that your choice of balsa will make a big difference to the final performance of a model of this size. The Fizza's strength lies in its design not in the materials, so you can use the softest, lightest balsa you can find, and the minimum amount of glue. Every ounce you save increases the Fizza's performance and your capacity for fun.
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A WING IN 20 MINUTES
After cutting the main wing panels and butt jointing them using the spar and spacers, glue two pieces of dowel along the lower half of each leading edge, leaving a 2 (50mm) gap between the dowels inner ends. This join is best carried out using medium cyano and should be made on a level surface to ensure that the wing is absolutely flat.
Next, add the tips, noting that the they extend 1/8 forward of the wing panel so that theyre level with the leading edge of the dowel. Use five-minute epoxy for this – a cyano joint may be too brittle to withstand profiling later on.
When everything has set, mark out the extent of the wing profiling with a line drawn 45mm behind, and parallel to, the leading edge. Then sand the wing so that it tapers down to the width of the dowel, being careful not to sand any flat spots into the rounded edge of the dowel. Once you're happy with the leading edge profile, cut a pair of ailerons from your trailing edge stock such that there's a 21/4 (55mm) gap between them in the centre, and a 1mm clearance at each tip. Don't hinge them permanently yet, though if you're using Mylar or flocked paper hinges you can loose fit them.
The taper of the ailerons completes the aerofoil section of the wing, so no further profiling is necessary. All that remains to finish is to taper the rear of each tip to match the ailerons.
The rods themselves can either be operated by nipped tube links from the servo pushrods, or you can try my new alternative method. This involves sliding a small piece of silicone tubing down the vertical part of the torque rod to form a seal, placing a commercial plastic aileron horn where required, and filling the hole in the top of the horn with epoxy. Although the horns initially feel very loose on the piano wire, the epoxy keeps them firmly in place and they'll never fall off. Having said all that, the access to the torque rods afforded by this model means that you can solder eyelets or ball links to them if you want a really cast iron set-up.
The fuselage is simplicity itself and has been designed with several issues in mind. For a start, making it a mid-wing model not only means that its cavernous battery bay will accept all manner of flight batteries, but also makes for a model that's extremely easy to hand-launch, as you can grip it firmly around its centre of gravity.
Once the epoxy has set, glue the front upper deck in place and, turning the fuselage upside-down, add the two 30mm lengths of triangular stock to the lower corners, and finally fit the front underside sheeting. This sheeting can be as firm as you like: its a lob-and-land model, after all, so this bit will take the brunt of your landings.
THE BLUNT END
With the front end of the model ready for shaping, turn your attention to the rear end. Here, former F2 needs to be tapered so as to meet squarely with the sides of the fuselage when theyre pulled together. When you're satisfied that each fuselage side will have an equal curvature and that the tail platform is level with the wing seat, glue the sides to the rear former. When set, add the rear lower sheeting to give the whole structure some rigidity.
Next, cut the large access hatch from light but firm 3/16 sheet, and trim it to give a perfect fit between the front and rear lower sheeting. I'll leave you to use your preferred method for retaining the hatch; I simply glue a 1/16 ply tongue to the front (which is a tight fit between the doublers) and use a single screw running into a retaining block glued to F1.
SHAPING THE FUSELAGE
The rear upper deck also needs to be shaped so that it curves smoothly along its entire length. It's important, however, not to remove too much material towards the rear; it must remain 3/8 (10mm) thick along its length.
With the access hatch in place, blend the three underside parts with each other, and with the fuselage sides so that you end up with a nicely rounded body that should be both light and strong.
MAKING THE TAIL
The tailplane's leading edge panels are made from slightly firmer balsa, and their inner faces are trimmed so as to meet the fuselage at the correct angle. Fit the tail surface tips using epoxy, and when everything's dry round off all the forward-facing edges before notching and joining the elevators with a piece of 1/8 dowel. Chamfer the elevators leading edge to allow correct movement, and check that there's a 1mm clearance between the elevator and the tips. Like the ailerons, the elevator shouldn't be permanently hinged until after covering, but again, if you're using Mylar or flocked paper hinges, you can loose fit it now.
When you glue the fin into place, take time to ensure that it is both vertical and aligned with the fuselage. Having rushed this job on other models and ended up with 88° fins that have resulted in hands-free circuits, I now pin the fin in place while I check its position, and only when I'm perfectly happy do I commit with the thin cyano.
Finally, before gluing the rear tail blocks into place, cut and sand them so that they extend the taper of the fuselage deck all the way to the rear of the fin. This not only finishes the lines of the model, but also gives the fin some valuable support.
You can cover the wing either before or after its slotted into place, though if you do it before you must ensure that the fuselage contact surface is left bare. Before you glue the wing into place make a final check that it'll be level with the tail, that the distance from wing corner to tail tip on either side is equal, and that there's sufficient root clearance for the ailerons.
NUTS, BOLTS & OPTIONS
Some of you may want to fit an intermediate former between the battery and the motor to avoid the two coming into contact in the event of a hard arrival. My own feelings, however, are that this would restrict cooling airflow in normal circumstances, and do little to restrain the flight battery in abnormal circumstances! Better by far to make sure your battery's well secured in the first place. Talking of cooling, make some air exit holes where you feel they're needed, the obvious place being towards the rear of the battery access hatch.
The Fizza canopy is available from Vortex Vac-form for £4.00 (inc. UK p&p). Although it has been designed to fit perfectly, there's no reason why you couldn't line the inner edges of the aperture with soft 1/4 square strip so that the edges of the moulding wont mark the wing. To attach the canopy, you can use a small screw front and back running into the upper decking, double-sided tape, or just glue it on if you're not worried about having access to the aileron servo or ESC.
While the mid-wing format makes the Fizza ridiculously easy to launch, its a good idea to get someone reliable to do it for the first flight so that your thumbs are on the sticks from the word go. That said, none of the Fizza's built so far have required any significant trimming – another major benefit of the models flat sheet wings and zero-zero incidence.
Whatever spec you choose, though, you'll have a model that flies as straight as a die, has no vices, and is virtually tip-stall proof. Its so responsive that it'll give you three rolls per second. With sufficient rudder movement you can really tie it up in knots with flick and spin manoeuvres, but all it takes to recover is to centre the sticks. Those who have already flown one of the prototypes haven't wanted to give the transmitter back, and several testers have described the Fizza as a balsa Formosa. Given that the Formosa was my favourite model of 2004, and probably inspired the Fizz in some ways, I'll take that as a compliment.
Vortex Vac-form (for the canopy)
Tel. 01162 207080
Model type: Sport / aerobatic
Designer: Nigel Hawes
All-up weight: 14oz
Rec'd powertrain: 8 x 6'' APC E prop, Typhoon 6/23-turn motor, 2s Konion or seven 650 AAA cells
Control functions: Aileron, elevator, rudder, throttle
Canopy: from Vortex Vac-form
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