BVR kits “WHIZZZA” – Instructions for Warwick Model Flyers.

This kit has been put together to complement the RCME free plan and subsequent options supplement which will be published in early spring of 2006.
As you know, your club has had the dubious privilege of getting 20 such kits to use as your 2006 club model WELL BEFORE publishing, and in order to help you assemble and operate the model successfully I have created these specific instructions especially for you.
As the plan is in Greece being converted to CAD, all you will have to go on are the pictures and captions on the www.whizzza.co.uk website and this document, and the RCM&E articles that Richard Lemare has on a CD-ROM so if you have any problems or queries beyond this, please direct them straight to me on 01228 560100 / 07770 832923 or E-mail me at mustprang@ukonline.co.uk 
Alternatively, quit the hobby and take up fishing. 

The Whizzza is basically an enlarged version of the hugely popular Fizza, but with far more emphasis having been put into smoothness, performance and aerobatic capability. The construction sequence is similar and will be familiar to any of you who have built the Fizza, but there are some significant differences so follow these instructions carefully and systematically, as they are very complete.

WING CONSTRUCTION.
It is better to begin with the wing, so locate panels 1 & 2 and after cleaning up the mating surfaces with a sanding block to ensure a flat, continuous joint, glue them together using medium cyano whilst sandwiching the 1/8” spruce spar (which should be absolutely central) and the spacer strips extending just beyond the panel ends. The excess spacer protruding from the ends can be trimmed when the cyano has fully set using a modelling knife or sanding block.

The spruce spar I have supplied in the kit is 12” long (as opposed to the 7” spar on the forthcoming plan) and is sufficient for up to .25 i.c. engines or 350 watt Electric power systems. Anyone wishing to power this model with more than 350 Watts or higher capacity i.c. engines has the option of using a FULL LENGTH 1/8” spruce spar instead of the short spruce spar and balsa spacer arrangement; this is not supplied in the kit but should be available from most good model shops.

Cut and glue the two lengths of the 4mm square hardwood strip along the leading edges of wing panel 1 making sure they are level with the lower edge so it is better to do this on a flat surface such as a building board. You may wish to use an adhesive such as PVA to get a good contact here.
There needs to be an approx. 2 inch (50mm) gap between the root ends of the hardwood leading edge strips, so when your fuselage is finished you can carefully trim them to achieve this remembering that you must trim EQUAL quantities from each strip to make sure the wing will end up central on the fuselage. Be sure not to overtrim these strips before final wing fitting!
Use the sanding block on the wing panel ends to ensure that the tips will achieve a good fit and bearing in mind that their foremost extent must line up exactly with the hardwood leading edge strips, glue tips 3 in the correct place with PVA or 5-MINUTE EPOXY; cyano is far too brittle for this joint.
Draw a profiling extent line 2½” (63mm) behind, and parallel to, the front edge of wing panel 1. These dictate the area where material needs to be removed. Then proceed to profile each side down to the 4mm hardwood leading edge strip using first a razor plane then reducing grades of abrasive paper until you have the desired leading edge taper.
 
The hardwood strip not only makes sure that uniformity of leading edge thickness is maintained, but due to its density, it affords great protection to the wing when in contact with stubble or obstacles during landings which would otherwise dent a soft balsa type leading edge. 
When you are happy with the profiling, “round off” the hardwood strip to a smooth curve using a sanding block.

Trim the ailerons 4 by equal amounts to ensure that there will be a 2 inch (50mm) gap between them at the root edge when fitted, as well as a 1mm working clearance to the wingtip. The inner gap can be adjusted when the fuselage is finished by trimming equal quantities from the inner edge of each aileron to ensure a 1mm working clearance to the fuselage sides when the wing is in place.
No wing profiling is necessary at the trailing edge (except for the tips which are done last) as the taper is provided by the natural angle of the aileron stock in its neutral position. However it is a good idea to hold the ailerons in position against the wing trailing edge on a flat surface and lightly sand out any thickness discrepancies between the aileron stock and wing panel 2.

Chamfer the rotating edge of each aileron to allow at least 1/2" (12mm) downward movement. Using pliers, carefully implement the required 90 degree final bend in the supplied torque rods ensuring that the yellow plastic tube is in the correct place. Epoxy these tubes to the upper centre of the trailing edges where shown, leaving 8-10mm between the left and right rods. Check for full, free operation of these torque rods as epoxy can quite easily foul their operation if any excess adhesive has contaminated the pieces of yellow plastic tubing. Drill the ailerons to accept the torque rods but DO NOT permanently hinge them until after covering. If using Mylar or flocked paper hinges, these can be dry fitted to establish correct aileron operation. You may need to cut relief grooves in the trailing edge panel to allow full torque rod travel.

The ailerons are operated by pushrods of your choice; all prototypes and display models used a Z-bend at the servo end and an adjustable clevis at the torque rod end.
Finally, with the ailerons held in place, taper the rear portion of wingtips 3 to exactly match each aileron. Apart from your preferred hinge method which should not be carried out permanently until after covering, wing construction is complete.

FUSELAGE CONSTRUCTION.
Begin by making up the fuselage sides by glueing the 1/8” (3mm) sheet doublers 5 to the inner edges of fuselage sides 6 ensuring that you make a right and a left side! The doubler on the throttle side of your chosen engine needs to have a portion cut out of it and the throttle snake outer glued in place at this early stage. IMPORTANT - The doublers should be positioned such that the UPPER edges are exactly in line with the upper edge of the fuselage sides and the front edge is SET BACK by ¼” (6mm) to allow for the firewall. Any discrepancy between doubler 5 and fuselage side 6 depths can be sanded out of the bottom of the fuselage before fitting the underside components. Add the strip doublers 5 to the upper and lower edges of the fuselage sides immediately behind the sheet doubler; these reinforce the wingseat and main access hatch.
The final position of these doublers dictates the former 7 position.
The remaining smaller lengths of strip doubler 21 should be glued along the rear lower edge of the fuselage sides leaving a 1/4” (6mm) gap for main former 7; these lengths of doubler will need to be trimmed slightly to match the rear fuselage taper. These strips reinforce the smaller access hatch.

Add the two 65mm lengths of flat-edged triangle stock to the front of the fuselage sides noting that the flat edge goes ON TOP of the fuselage sides and these pieces DO NOT go right up to the front; they need to be set 1/4” (6mm) back level with the front edge of the doublers to allow for the balsa strip on the top of the ply firewall. 
When dry join the two fuselage sides using main former 7, the sides should just come up to the origin of the taper in former 7. To aid fuselage integrity you can epoxy the firewall in the correct place at this stage, noting that the balsa strip on the top should locate with the two set-back pieces of flat-edged triangle stock and the firewall goes BETWEEN the fuselage sides, locating with the doublers.
The firewall will need to have a corresponding hole drilled in it for the throttle snake outer to pass through.

With the front end secure, pull the inner ends of the rear fuselage sides together onto rear former 8 ensuring that each fuselage side has equal curvature. When happy with the uniformity, glue former 8 in place. Note that the ends of the fuselage sides are simply rounded off, not tapered to a point; this provides a “chunky” mass into which the tailskid or wheel axle support block can be grafted later if you choose to have an undercarriage. Glue rear underside sheeting 10 in place and trim level.
The rear upper pieces of fuselage sides 6b now need to be glued in place one at a time, so chamfer their lower edges to the correct angle such that when leaning against the taper of former 7 they will contact the upper edge of main fuselage sides 6 correctly and all the way along. When happy with the fit, glue them in place - this is best done by firmly glueing them at the front level with former 7 and when set, gradually dripping thin cyano along the long edge whilst holding the slight curvature with your other hand. Naturally the first one is easier to do but if chamfered correctly even the second one will go in place without fuss. 
When these pieces are secure sand out the joint angle to a smooth curve with a sanding block and also run it along the rear upper faces to provide a flat contact area for rear deck 13 - after a dummy fit to check, glue it in place. You can now proceed to shape part 13, noting that it should not taper at all towards the rear but must be generously rounded along its entire length – use the rear shape of the supplied canopy to get the correct curvature at former 7 end.
There must be a tailplane platform of EXACTLY 2½ inches behind the rear deck, so measure it and adjust either the rear deck or rear ends of the fuselage sides to make this the correct length. 

You now have to insert your fuel tank and secure it, noting that the WHIZZZA i.c. version has been designed specifically for a 6oz SLEC square tank. Firstly, dummy fit the tank and drill the fuel delivery, filler and exhaust pressure tube holes in the firewall. Leaving more than enough spare length sticking out of the former, connect them up to the tank.
When satisfied, position the tank about 3/8” (10mm) back from the firewall (to be well clear of the sharp ends of the engine mount self-tapping screws) and secure it in place – the prototypes all used a “hot glue gun” for this with excellent results.

With the tank in place, top upper sheet 12 can be added. This part has been made deliberately narrow to make sure you round off the front correctly, we want no “LADA CARS” here, so use the flat-edged triangle to the full as that’s what it is there for. What’s more, as the i.c. version is wider than the proper, clean, quiet, powerful, modern, slime-free ELECTRIC version, you will find that the front of the canopy will be stretched to its maximum opening in any case so generous rounding will be necessary. Use the front of the canopy, fully opened out as far as it will stretch, as a guide to your final shape – you will find that if done properly it will “grip” the front sheeting.

Turning the fuselage unit upside down, use a sanding block to clean up and level the underside fuselage & doubler faces and glue crossgrain sheet 9b in place 2 inches (50mm) back from the front edge of the firewall. Trim the main access hatch 11 to an exact fit with the middle of former 7, the servo access hatch 11b fills the gap between hatch 11 and rear underside sheet 10. These hatches are secured using the supplied ply tongue at the front of 11 (making sure it is trimmed to a tight fit between the doublers) and the white plastic hatch block which needs to be glued to the front lower edge of former 7 and is drilled to accept the supplied screw. 
Support these blocks with some scrap triangle stock if you prefer. The smaller hatch 11b should also be retained the same way (but with the ply tongue at its rear end) as you will require regular access to charge the RX battery which will need to be in the rear portion of the fuselage to achieve the Centre of Gravity, quite far back with heavier engines! For this reason SNAKES are highly recommended for the rudder and elevator linkages.

Glue front underside sheet 9 into place with its rear edge against crossgrain sheet 9b. You will not only find that it has to be significantly shaped to match 9b (giving the front end of the model a nice chunky feel) but it also sticks out of the front as a base to build up the cowl cheeks etc. using part 22 which is supplied for this purpose, along with the two small pieces of triangle stock in the accessory pack for the lower corners. However due to the angles involved it is advisable to first screw the engine mount in place at the correct angle. This should be such that the silencer squirts all the slimy exhaust gunge UNDERNEATH the wing, but isn’t so tilted that it will contact the ground during landing.

The entire underside can now be lightly rounded, more at the front than the rear. The generous fuselage doubler arrangement allows a really curvy underside shape to be achieved without the structure going “thin” anywhere, especially where the hatches attach.

Dummy fit the wing and lay tailplane 14 in place, making sure they will be level with each other, adjusting one side of the TAIL seats if necessary. 
When this has been achieved you can either glue the tailplane in place (ensuring that the distances are equal between each wingtip and tailplane corner) and build it up with leading edge parts 15, or if you prefer to assemble the entire tailplane completely and cover it separately for ease, do this on a flat building board. Either way you may need to adjust the inner gap between parts 15 if necessary for correct contact with the fuselage, and after making sure of a flat contact area, add the tail tips 16.
The elevators 17 should be trimmed in length to allow generous rudder movement and these are joined by the small length of 3/16” (4.5mm) dowel supplied; measure and cut a recess in each elevator such that when in position a 1mm working clearance exists to each tail tip. Make a slot and EPOXY in place the ply control horn where necessary and chamfer the rotating edge to allow 1/2 (12mm) up and down movement; do not hinge the elevators to the tailplane until after covering.
The cutout in the front lower edge of fin 18 has been made undersize, as everyone will probably shape the rear of upper sheet 13 differently. Adjust this cutout so the fin fits correctly and glue it in place ensuring that it is both CENTRAL and VERTICAL. The Rudder 19 should be chamfered to allow 1 inch (25mm) each way movement but not permanently hinged until after covering, with the ply control horn Epoxied in place where necessary.

The area between the end of 13 and the rear of the tail unit is formed by shaping tail blocks 20 and when happy that they accurately continue the fuselage lines, glue them into place. DO NOT attempt to shape them after glueing in place as this will risk damage to the surrounding components.
The final major assembly task is to glue the wing in place making sure it is level with the tail assembly and there is equal distance from each wingtip and tail tip, if preferred it can be covered first leaving the areas to be glued bare. Epoxy or PVA should be used for this joint, preferably weighted down whilst the glue hardens overnight, especially for the “.36 nutter brigade”. You will need to trim the ailerons EQUALLY to allow wing fitting, an operating clearance of 1mm should exist between the inner edges of the ailerons and the fuselage sides – be particularly careful that they don’t “jam” at full down movement!

NOTE – For those with limited storage and transportation space a removable wing option has been developed for this model - full details will soon be published in the second part of the RCM&E magazine article, together with supplementary plans, as well as a fully captioned pictorial guide at www.whizzza.co.uk – or ask Richard Lemare for a copy of the disc containing these articles.

INSTALLATION AND FINISHING.
The aileron servo should be positioned BEHIND the spruce wingspar with conventional pushrod operation of the torque rods. Small ply plates can be glued onto the wing in front of and behind the servo for it to be retained by screws. A standard servo will fit, but if using smaller servos do not use anything below the GWS PARK 17g servo, which is available at low cost from www.brchobbies.co.uk 
The elevator and optional rudder servos are either glued to the fuselage inner sides behind former 7 or screwed to bearers across the fuselage if preferred.  Insert your choice of rudder and elevator snakes and create the linkages ensuring full free movement exists – you may have to “build in” the RX battery (positioned to achieve the Centre of Gravity) before securing the servo ends of the snakes permanently.

Trim the canopy a little at a time until it snugly fits the front and rear fuselage decks and just touches the wing all the way along their chord. (If you make a real mess of your canopy, or damage it in a crash, I can supply replacements at £5 inc. P&P). The canopy is then either double-sided taped, glued or screwed in place depending whether access will be required to the aileron servo.

The model has been designed to be extremely tolerant to Centre of Gravity deviations, but as a guide, 3 to 3½ inches (75 to 90mm) behind the leading edge at the wingroot is a good starting point depending on your taste. Make sure you secure the RX battery extremely well but allow for moving it slightly to find your C of G “sweetspot”.

We recommend a simple lightweight covering such as Solarfilm for the Whizzza, as it is quick and easy to apply as well as being colourful and strong. A good contrasting colourscheme will pay dividends especially on higher-powered versions which can cover the sky at an alarming rate! Make sure all control surfaces are hinged VERY securely, pegging if deemed necessary.
There are dozens of suitable ELECTRIC power systems for this model but special rates have been negotiated with BRC HOBBIES so check out the website at www.brchobbies.co.uk for the latest bargains when you “see the light” and ditch your old i.c. fossils.

Recommended control movements are:

Ailerons:         1/2” (12mm) each way, (with 3/8” or 9mm on low rates)

Elevators:       1/2” (12mm) each way, (with 3/8” or 9mm on low rates)

Rudder:           1 inch (25mm) each way.

FLYING!
Being of mid-wing configuration, the Whizzza is extremely easy to launch but it is advisable to get a reliable launcher to do the job for you on the test-flight.
After checking airframe, control surface and radio gear integrity and carrying out a range test, launch straight and level into a breeze at full power (and preferably low rates until you get used to the control sensitivity) then climb to a safe height to trim the model.

The Whizzza has been designed to be purely for FUN flying and you will soon achieve your ideal control movement set-up which can extend to extreme aerobatics if desired. In flight it is smooth, predictable and safe and therefore also suitable for less experienced pilots with lower power configurations using low rates (60% full movement).

The Whizzza is extremely tolerant to Centre of Gravity changes as mentioned above, and with a little experimentation you will find the position which suits your flying style best.
As the model carries momentum very well it is advisable to carry out a couple of dummy approaches to establish its glide characteristics before committing yourself to a landing.
It is best to keep the speed up on your first landing approach especially on heavier versions but the flat sheet wing is very forgiving and the model has extremely benign stall characteristics if you slow up too much. All in all you will find this to be a very pleasing model to fly!

Inevitably due to the competitive nature of your need for this model, some of you will have the odd bump here and there, others will make it into complete toast. However in deliberate crash testing (honest) we have found that the wing almost always survives intact.
For this reason, and for the Warwick Model Flyers only, I am producing a “front end repair kit” which includes all fuselage components as far as just behind former 7. This will be available for £10 inc. P&P and can be added to with additional components on request.
Furthermore I will honour the £40 per complete kit for full replacement or other club members wishing to join in, but please note that P&P is £5.

I hope you have a great deal of pleasure building flying and particularly CRASHING your WHIZZZAs!

Nigel Hawes, January 2006.