Anyone who built the Fizza will have a head start here as the basic construction bears great similarity.
When the panels have been joined with the spar between, add the spruce l.e. strip each side (leaving a suitable gap in the middle for the fuselage front deck) and glue the tips in place with epoxy. Draw the 60mm profiling line behind, parallel to the spruce strip, and profile the l.e. down to the spruce making a smooth, uniform section using a razor plane and sanding block. The square spruce strip is then simply rounded off. Theres no t.e. to profile, as the taper of the ailerons provides this. Whizzza uses hefty 10 x 45mm aileron stock which, if you cant get from model shops, is easy enough to make from soft sheet. With the ailerons held in place all that remains is to sand the rearmost area of the wingtips to match and you have a completed wing! A good panel will weigh 6oz (170g); any more than 7oz and you can be sure that the sheet youve used is far too heavy.
The fuselage is made from light soft sheet, as the strength is in the design and not the materials used. Don’t be embarrassed to take your digital scales into your local model shop and come away with the lightest sheets they have.
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TAIL UNIT & FINISHING
With the wing laid in position, fit the stabiliser to establish that its level with the wings, making slight adjustments to the stabiliser seat until things line up – when satisfied you can glue it in place ensuring equal distance between its front corners and the rear wingtip corners. If, however, you prefer to build and cover each of the major tail components first, simply assemble them off the model but do plenty of dummy fitting to ensure all will be level and square, as this is key.
COVERING & INSTALLATION
The prototypes were covered in either Solarfilm or Easycoat but you can use any sensible method you like. Solartex would possibly be a bit extreme, but Profilm is acceptable. Its easier to cover the wing separately from the fuselage / tail unit and then join them later. Furthermore, as the aileron linkage is specific to the wing, you can completely gear up the various linkages and attach the wing (using 5-minute epoxy) as one of the very last tasks – make sure it’s level with the tailplane and that the aperture made in the main former is sufficiently large to avoid fouling of the aileron torque rods.
Snakes or pushrods can be used for elevator and rudder control, but be sure to use appropriate servos. Higher-powered Whizzzas will be capable of speeds well in excess of 100mph, so use something like the 12g Naromax BB micro servos for these surfaces. A decent mini-servo is recommended for the ailerons, such as the 17g GWS Park servo.
SET-UP AND FLYING
Probably the most daunting thing about any electric model, especially to the newcomer, is the choice of powertrain. There are so many motors with confusing numbers on them, and then you have to choose an appropriate ESC with a decent operating margin. A battery capable of providing sufficient current and capacity will also be needed, and if a Li-Pos chosen itll need to have a large enough ‘C’ rating for the job in hand. Finally youll need to choose a prop that allows all the chosen items to work together in harmony- no wonder people get confused!
The high quality, low cost Hyperion 3013-14 and X-Power ESC are available from BRC Hobbies at a special combo price for Whizzza builders of just £74.95 for the 350W set-up using the 40A ESC, and an amazing £69.95 for the 250W set-up using the 30A ESC. In operation these motors are super smooth, cool running and very powerful; using a 3s Li-Po and 10 x 8 Master electric-only prop gives excellent vertical performance on full power. Throttle back to a sport setting rather than out-and-out hooligan mode and they seem to be extremely efficient – I’ve had 30-minute flights out of a Polyquest 4400 3s Li-Po and the model wasnt hanging about at all.
I hope the Whizzza will have even wider appeal than the extremely popular Fizza. Its ideally poised to benefit from the current attention surrounding 480 / 600-size brushless motors and controllers, which has brought their price well into affordable realms, and will hopefully make up for any disappointments youve had with previous 600-size sport models that suffered from the can motors lack of power and longevity. Flying the Whizzza is an absolute blast, and with the optional undercarriage and removable wing facility Ill describe next month, its not limited to the small-model, flat-field brigade; this is a model that every sport flyer can use and enjoy.
One of the reasons for including 3/16 x 1/2 doublers to strengthen the wing seat and battery access hatch aperture was to leave a void suitable for the load bearing plates required for an undercarriage. This allows the entire structure to be installed without compromising the battery area whatsoever!
AT THE BACK
To complete the tail dragger type landing gear, use either a simple skid or a tail wheel. The latter is a little fiddly and vulnerable on a model of this size, but as the mounting system is the same you can make the exiting piano wire into either a skid or an axle – the choice is yours!
READY TO ROLL
All that remains is to fit some wheels. Probably the best to consider are lightweight sponge jobs as, not only do they look good on the model, their weight and drag are more or less insignificant. As a point of interest, the addition of the complete undercarriage system adds less than 3oz (85g) to the all-up-weight of the Whizzza and thus has an almost negligible effect on flight performance.
Due to the gap at the front of the wing, that allows the motor-to-ESC wiring to pass through, there isn’t anywhere strong enough for the usual tongue or dowels to locate. So, the method shown on the plan was developed, and this has proved totally effective and reliable. Instead of being embedded in the l.e. as normal, the dowels are located at the rear of the wing, whilst two appropriately drilled hardwood blocks are positioned at the forward end of the fuselage / wing bay to accept nylon wing bolts.
Finally, for the benefit of those who will never see the electric light, Ive developed an i.c. version of the Whizzza for .20 – .25 two-stroke power. The model is fundamentally the same but with changes at the front – as you can see from the alternative sections on the plan, the main former is slightly wider.
Fuel proof the entire nose area before covering, and locate the plumbing; tank pressure and filler pipes can either exit the front upper deck or come through the engine mount centre, along with the fuel delivery pipe. Theres plenty of space for the r/c gear, simply arrange the servos and Rx battery to achieve the correct C of G. I would advise a mini servo for the throttle, but you can use standard jobs for the rudder and elevator in line astern, with another standard servo for the ailerons.
A big thanks to Richard LeMare and the Warwick team, as their enthusiasm for the design and feedback has helped me develop the i.c. version of the Whizzza into the well-sorted item presented here.
So thats about it. You’ve got the plans for a cracking 600 BL sport model that has fantastic performance even on budget brushless electric flight gear, the facility to add a strong and effective u/c and, what’s more, you can give it a removable wing if you so desire. Of course, there’s also the i.c. version if you’re still not convinced of the benefits that electric flight has to offer! Any (or all) of these modifications can be made without affecting the fundamental design, so all that remains is for you to build one.
Model type: Electric aerobatic
Designed by: Nigel Hawes
Wingspan: 42” (1067mm)
Fuselage length: 36” (914mm)
Wing area: 315 sq. in.
All-up weight: 40oz (maximum)
Wing loading: 18oz / sq. ft.
C of G: 80 – 95mm from root l.e.
Motor: 600-size brushless
Battery: 3s 2000mAh Li-Po
Control functions: Aileron, elevator, rudder, throttle
Control deflections: Aileron ±1⁄2”, elevator ±1⁄2”, rudder ±1”
Hardware: Canopy available from Vortex Vac-Forms tel. 01162 207080. Sticker sheets from M.troniks tel. 01943 461482
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