Instruction Manual Composite-ARF SPARK - michel … SPARK [email protected] Instruction...

[email protected] SPARK

Instruction ManualComposite-ARF SPARK

TAVS Technology version 1.0

Instructions for SPARK Jet airplaneThank you very much for purchasing our Composite-ARF Spark all composite jet aircraft, madewith the revolutionary Total Area Vacuum Sandwich (TAVS) technology

If you want a full-color version of this manual, you can download it free from our website as anAdobe Acrobat .pdf file and print it (paper size A4). Just go to the ‘Spark’ page on our website,and click on the link named ‘Download Instructions’ above the top photo of the product.

Before you get started building and setting-up your aircraft, please make sure you have read thisInstruction Manual several times, and understood it. If you have any questions, please don’thesitate to contact your Rep., or us. Below are the contact details:

Email: [email protected] [email protected]: Phone your C-ARF Rep!!! He will be there for you.Website: http://www.composite-arf.com

Liability Exclusion and DamagesYou have acquired a kit, which can be assembled into a fully working R/C model when fitted outwith suitable accessories, as described in the instruction manual with the kit.

However, as manufacturers, we at CARF-Models Co. Ltd. are not in a position to influence theway you build and operate your model, and we have no control over the methods you use toinstall, operate and maintain the radio control system components. For this reason we areobliged to deny all liability for loss, damage or costs which are incurred due to the incompetentor incorrect application and operation of our products, or which are connected with such opera-tion in any way. Unless otherwise prescribed by binding law, the obligation of the CARF-Modelscompany to pay compensation is excluded, regardless of the legal argument employed.

This applies to personal injury, death, damage to buildings, loss of turnover and business,interruption of business or other direct and indirect consequent damages. In all circumstancesour total liability is limited to the amount which you actually paid for this model.

BY OPERATING THIS MODEL YOU ASSUME FULL RESPONSIBILITY FOR YOUR ACTIONS.

It is important to understand that CARF-Models Co., Ltd, is unable to monitor whether youfollow the instructions contained in this instruction manual regarding the construction, operationand maintenance of the aircraft, nor whether you install and use the radio control systemcorrectly. For this reason we at CARF-Models are unable to guarantee or provide acontractual agreement with any individual or company that the model you have made willfunction correctly and safely. You, as operator of the model, must rely upon your own expertiseand judgement in acquiring and operating this model.

Composite-ARF SPARK [email protected]

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Important Supplementary Notes

Pre-Flight Checks:Before every session check that all the model’s systems function correctly, and be sure to carryout a range check. The first time you fly any new model aircraft we strongly recommend that youenlist the help of an experienced modeller to help you check the model and offer advice whileyou are flying. Be certain to use the recommended CG position and control surface travels. Ifadjustments are required, carry them out before operating the model. Be aware of any instruc-tions and warnings of other manufacturers, whose product(s) you use to fly this aircraft.

Check very carefully that the flight batteries are securely held into the model, and cannot comeloose during flight maneouvres. Check that the 6mm carbon pins in the front of the the wings andstabiliser are not loose. Check that the wing and stab retaining bolts are tight, that the canopyframe is securely held onto the fuselage with the wire from the nose.

Please don’t ignore our warnings, or those provided by other manufacturers. They refer to thingsand processes which, if ignored, could result in permanent damage or fatal injury

Attention !This jet aircraft is a high-end product and can create an enormous risk for both pilot and spec-tators, if not handled with care, and used according to the instructions. Make sure that you oper-ate your Spark according to the the laws and regulations governing model flying in the countryof use.

The fan unit (or turbine), servos, R/C equipment, batteries and landing gear have to be attachedproperly. Please use only the recommended EDF unit and accessories. Make sure that the‘Centre of Gravity’ is located in the recommended place. A tail heavy plane, especially in the firstflight, can be an enormous danger for you and all spectators. Fix any weights, and heavy itemslike batteries, very securely into the plane. Make sure that the plane is secured properly beforeyou switch on the Fan unit or start the turbine. Check for vibrations through the whole throttlerange - there should be no vibration at all from an EDF or turbine.

Make sure that you range check your R/C system thoroughly before the 1st flight. It is absolute-ly necessary to range check your complete R/C installation first WITHOUT the engine running.Leave the transmitter antenna retracted, and check the distance you can walk before ‘fail-safe’occurs. Then start fan unit or turbine, run it at about half power and repeat this range check withthe motor running. Make sure that there is no range reduction before ‘fail-safe’ occurs. Only thenmake the 1st flight. If the range with motor running is less then with the motor off, please contactthe radio supplier/engine manufacturer and DON’T FLY at that time.

Please read the whole of the this Instruction Manual completely, and make sure

that you understand it all fully, before starting the assembly of your Composite-

ARF ‘Spark’. It will save you time, effort and $$ in the end !


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Fully-composite aircraft structureThe fuselage, wing and stabiliser are produced in negative molds, manufactured using vacuum-bagged sandwich construction technology. Due to very careful design, material selection andlamination processes the Spark has incredible strength, yet an extremely lightweight airframe.

The composite sandwich parts are extremely strong, but fragile at the same time. Always keepin mind that these contest airplanes are designed for minimum weight and maximum strength inflight. Please take care of it, especially when it is being transported or stored by covering the fly-ing surfaces with the protective padded bags included in the kit, to make sure that none of thecritical parts and linkages are damaged.

All parts are painted in the molds, either single color or designer schemes. A production methodcalled TAVS (Total Area Vacuum Sandwich), enables us to present this aircraft with incrediblebuilt-in strength, while still being extraordinarily lightweight, and for a price that nobody couldeven consider some years ago. This production process has huge advantages, but a few disad-vantages also. These facts need to be explained in advance for your understanding.

Description of Parts

The Wings:Both wing halves are made in negativemoulds, and fully vacuum bagged, using only2 layers of 2 oz. cloth in combination with avery hard 2 mm foam sandwich to form a hardand durable outer skin.

The ailerons and speedbrake are hinged, cutloose and trimmed already for you - laminatedin the mould and attached to the wing with aspecial nylon hinge-cloth, sandwichedbetween the outer skin and the foam. Thisnylon hinge is 100% safe and durable. You will never haveto worry about breaking it, or wearing it out.

There is no gap at all on the top wing surface, and there isa very narrow slot in the bottom surface, where the aileronslides under the main wing skin during down throw. Thismeans that the hinge axis line is on the top surface of thewing, not in the centre. This is NOT a disadvantage, if youprogram in about 10% NEGATIVE aileron differential inyour transmitter. This means that the ‘down’ throw needs to be about 10% more than the upthrow. Why? Because the axis of the hinge is not at the centreline of the aileron, so it movesslightly in and out when operated, and the aileron gets a little "bigger" in surface area when mov-ing up, and "smaller" when moving down.

The bottom slot needs some explanation, too. The cut line is exactly in the correct position sothat the aileron slides under the wing skin smoothly. If the cut was a few mm forward or back, itwould not work properly. So, make sure that the lip is not damaged, and that the aileron slidesunder this lip perfectly. It will NOT lock at any time, if the lip is not damaged. If damage occursto the lip, you can cut off 2-3 mm, but you should NEVER need to cut off more than this.

Centreline of hinge axis

Phenolic control horn

The Fuselage: The fuselage is also made in negative moulds; with the main fuselage from composite laminates,and the vertical fin using TAVS construction. The main internal parts and bulkheads for the fanunit/turbine mount, nosegear, wing and stabiliser fixings etc are glued in during manufacture, toensure accurate location and reduce the assembly time for you. Very careful use of reinforce-ment at the critical places results in a strong and stiff fuselage, but still extremely lightweight.

The Stabilisers:The stabiliser is also vacuum bagged sandwiched, and the elevator is elastic-hinged in the samemanner as the ailerons. The horizontal stab is mounted with one Ø 6mm carbon rod at the frontand two M4 bolts at the back, which screw into threaded inserts that are laminated into the fuse-lage during manufacture.

Tools and Adhesives

Tools etc:This is a very quick and easy plane to build, not requiring special techniques or equipment, buteven the building of Composite-ARF aircraft requires some suitable tools. You will probably haveall these tools in your workshop anyway, but if not, they are available in all good hobby shops,or hardware stores like "Home Depot" or similar.

1. Sharp knife (X-Acto or similar)2. Allen key set (metric) 2.5mm and 3mm3. Sharp scissors4. Pliers (various types)5. Slotted and Phillips screwdrivers (various sizes)6. Drills of various sizes7. Dremel tool (or Proxxon, or similar) with cutting discs, sanding tools and mills.8. Sandpaper (various grits), or Permagrit sanding tools (high quality). 9. Carpet, bubble wrap or soft cloth to cover your work bench (most important !)10. Clear Car wax polish (for protecting painted areas close to glue joints).11. Denaturised alcohol, or similar (for cleaning joints before gluing)

Adhesives:Not all types of glues are suited to working with composite parts. Here is a selection of what wenormally use, and what we can truly recommend. Please don’t use inferior quality glues - you willend up with an inferior quality plane, that is not so strong or safe.

1. CA-Glue ‘Thin’ and ‘Thick’ types. We recommend ZAP, as this is a very high quality.2. 5 minute-epoxy (highest quality seems to be Z-Poxy)3. 30 minute epoxy (stressed joints must be glued with 30 min and NOT 5 min epoxy).4. Epoxy laminating resin (12 - 24 hr cure) with hardener.5. Microballoons, for adding to slow epoxy for lightweight filling.

We take great care during Production and Quality Control at the factory to ensure that all jointsare properly glued, but recommend that you double-check these yourself and re-glue any thatmight just have been missed. If you find any areas that need additional glue, sand and clean thearea carefully first, and re-glue with a thick mixture of slow epoxy and micro-balloons.

When sanding areas on the inside of the composite sandwich parts to prepare the surface forgluing something onto it, do NOT sand through the layer of lightweight glasscloth on the inside


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foam sandwich. It is only necessary to rough up the sur-face, with 120/180 grit, and clean off any dust with ace-tone or de-natured alcohol (or similar) before gluing tomake a perfect joint. You should always prepare bothparts to be joined before gluing for the highest strengthjoints. Don’t use Acetone or paint ‘thinners’ for cleaningexternal, painted, surfaces as you will damage the paint.

Tip: For cleaning small (uncured) glue spots or marks offthe painted surfaces you can use old-fashioned liquid cig-arette-lighter fuel, (eg: ‘Ronsonol’ or equivalent). Thisdoes not damage the paint, as Acetone and many other sol-vents will, and this is what we use at the factory.

At Composite-ARF we try our best to offer you a high quali-ty kit, with outstanding value-for-money, and as complete aspossible. However, if you feel that some additional or differ-ent hardware should be included, please feel free to let usknow. We know that even good things can be made better !

Email us: [email protected].

About the Spark (EDF version)The focus on the design of a high performance electric jet needs to be different than on a tur-bine powered jet. So CARF came up with a decisive new design, taking electric sport jet per-formance to a new level. The Composite-ARF Spark.

The Spark is consequently designed as a very lightweight all-composite structure, with fea-tures similar to a world class F3A-Pattern plane. Lightest lay-ups, perfectly engineered aerody-namics and structural reinforcements only where they are needed; the Spark is perfectly suitedfor electric ducted fan flying (EDF).

We designed our Spark around the Schübeler DS-75 Ducted Fan, developing a static thrust ofapprox. 5 kg. Perfect ducting, molded intake lips and carefully calculated exhaust duct makesure this thrust is used with maximum efficiency to propel the Spark through the air, with animpressive 1:1 thrust:weight ratio.

The airplane's geometry and airfoils are designed for a very wide speed range at minimumdrag, allowing fast fly-bys as well as precise aerobatics. Landing speeds are very low, due tothe airfoil design and the speed-brake in the center of wing, just below the fuselage.

Our Spark's size is very carefully planned, so that you can fly with the performance of the realbig guys, but can stay with just that slightly smaller fan, that slightly smaller battery, that slightlysmaller motor - which saves you serious money on the one hand, and converts the power ofthese just slightly smaller components into breathtaking flight performance.

Of course, as usual, the CARF Spark is highly prefabricated and builds very easily and quickly,supported by a very detailed instruction manual, which also guides you through the electricalinstallation with lots of hints and tips. With a CARF Models Spark you barely can do anythingwrong, whether its your first jet, your first electric, your toy for the weekday evenings, or yourhigh-performance contest tool.


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Lighter fluid is excellent for clean-ing small marks, clear wax, uncuredglue, or similar off the painted sur-face of the plane.

AccessoriesThis is a list of the things you may need to get your Composite-ARF EDF-powered Spark intothe air. Some of them are mandatory, some of them can be chosen by you. What we list hereare highly recommended parts, and have been thoroughly tested.

1. DS-75 EDF unit, Lehner 2240-15 motor & 100 Amp speed-controllerWe strongly recommend that you use this EDF unit as the Spark is totally designed aroundit. It is available as an option from C-ARF, and comes fully wired, balanced and tested - and packed with the Jeti Spin 99 controller. (Product #864003).

2. Flight batteries. We recommend two 5S Lipo packs of minimum 5000mAH, with maximumdimensions of 165 x 45 x 60mm, and max. weight 675 grams each. A pair of high-qualityHDHE Lipo packs of 5200mAH is available as an option from C-ARF (Product #865001).

3. Spring-Air 301 ‘Firewall’ retractable landing gear set. The Spark was designed around thiseconomical, lightweight and reliable gear, and it is available as an option from C-ARF. (Product #740500)

4. Servos (min. 8). We recommend JR DS3328 or 3301’s for the elevators, ailerons and rudder. Due to the slim section of the stabiliser it is necessary to use a max.15mm thick servowith an integral wing-mount bracket. An alternative for the elevators is the JR DS161 or DS168 servo which also incorporates wing mount brackets. The speedbrake requires a standard sized servo with minimum 5kg torque (eg: JR 5391 or 8311). We used a JR3341for the nosegear steering. The retract/brake valve can be controlled with any small servo of minimum 2kg torque - such as a JR3341 or JR331 micro servo.

5. 5 heavy duty plastic servo output arms (single-sided), for the aileron, elevator and speed-brake servos. (eg: Graupner # 3544 or JR # 0315)

6. Main and Nose wheels 55 - 60mm (2.25 - 2.5"). You can use any high quality plastic wheels. An optional set of Behotec ‘slim’ wheels, designed specially for the Spark is available from C-ARF (Product #740550). The set includes 3 dual ball-raced wheels @ 60mmdiameter, 3 bolt-on axles, 2 brake units and a very compact combined retract/brake valve.

7. Receiver battery. We recommend a 2S Lipo of around 1500mAH, as the Spark only drawsabout 80 - 100mAH per flight from the small servos.

8. Switch for Receiver battery. We highly recommend the Powerbox Digi-Switch for a 2S 7.4volt Lipo, or the Powerbox Smart-Switch if using a NiCD or NiMH pack. The Digi-switch isavailable from C-ARF as an option (Product # 960610)

9. Charger & balancers for Lipo Flight batteries. (eg: Orbit, Schulze, Graupner, Emcotec etc)Suitable large cross-section charging cables with Ø 4mm gold connectors.

10. High quality servo extension cables, with gold connectors.


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Building Instructions

General TipsWe recommend that you follow the order of construction shown in this manual, generally start-ing at the back of the plane and working forward - as it makes access to everything easier andsaves time.

Protect the finished paint on the outside of the model from scratches and dents during buildingby covering your work table with a piece of soft carpet, cloth or bubble-plastic. The best way tostop small spots of glue getting stuck to the outside painted surfaces is to give the whole model2 good coats of clear car wax first, but of course you must be sure to remove this 100% proper-ly before adding any additional paint, decals or trim.

When sanding areas inside of the wing or stab to prepare for gluing something onto it, do NOTsand right through the layer of lightweight glasscloth on the inside foam sandwich! It is only nec-essary to rough up the surface, with 120 - 180 grit, and wipe off any dust with denatured alcohol(or similar) before gluing to make a perfect joint. It is very important to prepare the inside of thefuselage properly, by roughing up and cleaning the surface, before gluing any parts to it.

Don’t use activator (‘kicker’) when applying CA glue to the lightweight foam sandwich structureof the wing, stabs and fin, or the fibreglass skin of the fuselage, as it can cause the glue to gethot, and could cause a blemish on the outer painted surface.

Make sure that all bulkheads and parts that you glue into the fuselage are a loose fit (1 - 2mmgap all around) and glue them in with a mixture of slow epoxy and micro-balloons - otherwiseyou may be able to see a mark on the outside of the fuselage.

Be very careful not to add any uneccessary weight in the nose area (EDF version Spark), other-wise you may need to add lead in the tail to set the Centre of Gravity correctly.


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A view of the complete SPARK kit contents - Product #742000

Rudder

Install the rudder servo and linkage first, so you won’t haveto remove the thrust tube again later. The Fin is very narrowand it it only possible to fit a servo of up to 15mm (5/8”) thick.We recommend a digital servo of not less than 4 kg (55oz/in) torque, for example the JR/Graupner DS3328, 3301or 3401. If using a servo with an integral wing-mount brack-et (eg: DS3328) then you can cut, or file, this off.

The servo is mounted inverted, and screwedonto a pair of small 6mm thick plywood railsmade by gluing two short lengths of the supplied3mm thick plywood strips together as shown inthe photo. The upper one is normal plywood andthe lower one is liteply. Glue them together withthin CA, and sand the lengths to fit inside the finand against the back face of the fin spar. Securethe servo using the screws supplied by the servomanufacturer, with the servo output shafttowards the back of the plane. Fit a short plasticservo horn, and centre it with your R/C.

Apply masking tape to the left outside surface ofthe Fin, and draw a line exactly at 90 degrees tothe rudder hinge line, in line with the factory-installed rudder horn. Measure from the back ofthe fuselage to the fin spar and then mark this onthe tape, as shown. Using the servo that isalready screwed to the ply mounts you can eas-ily determine the position of the 25mm long x5mm high slot to cut for the servo arm. Cut it outwith a sharp knife, and sand to final size.

Lightly sand and clean the inside of the fin wherethe servo rails will be glued, and then tack thecomplete servo and rails assembly in place witha little thick CA, aligning the servo arm with thecentre of the slot and the rudder horn. Removethe servo and reinforce the joints carefully with afillet of slow epoxy.

Make up the linkage from the M3 x 60mmthreaded rod, M3 nuts and steel clevises asshown. The clevise on the linkage needs to be inthe hole that is 13mm (1/2”) from the centre of the servo. Test the servo travel, throws and cen-tering, loctite one end of the linkage - and then trim and glue the painted plastic fairing over thefront of the linkage with a drop of thick CA. You do not need to scuff the painted surface of thefin, the CA sticks to it fine !!

Make up the extension lead needed from your servo to the nose area, for RX connection, androute it down the side of the fuselage now.


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(above) Rudder servo mounting plates mustbe securely glued to both skins of the fin, andalso the back of the fin spar, with epoxy.(below) Rudder linkage can be covered withthe small painted fairing supplied in the kit.

EDF installation

Start the main assembly of the Spark byinstalling your EDF (Electric Ducted fan) unit,and completing the inlet and exhaust ducting.The inlet ducts have been factory installed foryou, and the clear fibreglass ‘Inlet Joiner’ tubeconnects these to the EDF. The milled plywoodfan mounting rails are already installed in thefuselage.

The Spark is designed around the 115mm (out-side diameter) Schübeler DS-75 unit, which isavailable directly from composite-arf as anoption (Product #864003). The EDF unit comeswith the Lehner motor installed, and the 4-bladecarbon fan attached and balanced, and needsno work from you - except for attaching the light-weight molded carbon fan mount to the shroud.

It is very important that the that mount is accu-rately assembled and glued to the shroud, andthat the completed unit is carefully bolted to theply mounting rails to ensure that there is no dis-tortion of the shroud, which would affect theclearances between the blade tips and theshroud.

Lightly sand and clean all 3 pieces of the mount-ing bracket carefully, using 400 grit paper, orbetter is green Scotchbrite. Assemble the 3 car-bon parts as shown, exactly at 90 degrees toeach other. Tack together with a very little thinCA, working on a waxed plastic/glass sheet soyou don’t glue the mount to the table!

IMPORTANT: The 2 carbon mounting tabs thatwill be bolted to the ply mounting rails in thefuselage must be positioned in line with 2 oppo-site carbon stators in the shroud, as shown inthe photo on the next page. The back edge ofthe tabs should be positioned 6 - 7mm from theback edge of the shroud - NOT flush with theback of the shroud as shown in the instructionsthat come with the Fan unit.

Mask off the area where the mount will be gluedto the shroud, very lightly scuff the gluing areas,and clean off all dust carefully. Tack glue themount to the shroud with 2 or 3 small drops ofthin CA and check alignment. When satisfiedglue the joints fully with a little thin CA, and then


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(top) Schübeler DS-75 EDF unit comes fullyassembled, balanced, wired and tested.(above) Assemble the fan mount with thinCA, working on a plastic sheet or waxed glass. (below) Mask off shroud and scuff with greenScotchbrite for good glue adhesion.(btm) The back edge of the fan mount shouldbe 6 - 7mm from back edge of shroud.

6 - 7mm


reinforce with a small bead of medium CA. DoNOT use any activator/kicker or the CA glue andshroud will turn white and ugly, and the heat pro-duced could even deform the shroud.

Now take the clear fiberglass inlet joiner andsand the front and back flanges to 10mm wide.Trial install the inlet joiner over the back of theinlets and check for a smooth fit. The joiningflange should be at the top, on the fuselage cen-treline, and you can sand this flange down toabout 6mm high everywhere. Also check thatthe back of the inlet joiner fits smoothly over thefront of the fan shroud, and sand it a little if nec-essary.

With the fuselage upside down, place the fanright at the back of the plywood mounting railsand tilt it upwards about 30 degrees as shown,and then slide the inlet joiner over it. Then youcan push both parts down and forward together,until the inlet joiner fits over the back of theinlets. If necessary you can reduce the width ofthe flange on the front of the inlet joiner to 5 or6mm allow easier fitting.

Check carefully that the 2 carbon fan mounts sitcompletely flush on the plywood mounting rails,and cannot distort the shroud when they arebolted down. If there is any small gap under themounts then you must pack this out with a shimmade from thin plywood or plastic sheet.

With the fan unit and inlet joiner in their finalposition, carefully mark the 4 mounting holepositions, remove the fan and drill the holes Ø4.5mm. Fit four M3 T-nuts under the ply mount-ing rails and hold in place with a drop of 5 minuteepoxy while you re-install the fan unit and tight-en the M3 x 12mm allen bolts (with washers) toset perfect alignment. The fan shroud should nottouch the plywood mounting rails at any posi-tion. The inner edges of the T-nuts project insidethe mounting rails a little, and can be ground offafterwards.

Thrust tubeThe thrust tube is made from very thin mylar sheet, and there are 2 sheets included in the kit,already cut to shape - to allow you to make a spare tube if necessary. The front should slide tight-ly over the outside of the fan shroud (Ø 115mm), and the back should be approx. 89mm diame-ter. During prototype flight testing we tried many different diameters of thrust tube outlet, but89mm proved the best compromise between static and dynamic thrust with the Schübeler DS-

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Step 1

Step 2

Step 3

(above) The carbon fan mounting tabs shouldbe positioned opposite to 2 of the stators.(below) A step-by-step view of how to insertthe EDF unit and inlet joiner into the fuselage.

75 EDF unit. The tube should be joined usingcontact adhesive at the overlap, and also alength of clear tape on both the inside and out-side surfaces of the overlapping joint.

Make up the jig used to join the thrust tube usingthe 2 milled plywood discs included in the woodpack. The front disc is 115.25mm diameter, andthe rear disc is 89mm. There is a 12mm diame-ter hole milled centrally in each disc. Join themusing a straight length of suitable tube (wood,fibreglass etc) of at least 12mm (1/2”) diameter,spaced apart at 560m (22”). Tack glue a balsasheet stiffener onto one side, as shown, to pro-vide a straight edge for the 20mm wide overlapof the mylar sheet where you will glue and tapeit together.

Very lightly sand and clean the overlapping partsof the mylar with 400 grit sandpaper, to providea good key for the contact-adhesive. We used‘Zap-a-dap-a-Goo’ to join all the tubes of the pro-totypes, and this works very well indeed. Apply avery thin layer to both surfaces at the overlap,wait until they are dry to the touch (2 - 4 min-utes), and then join together with the mylarsheet wrapped tightly around the jig. With thetube still on the jig apply 1 piece of strong cleartape along the overlapping joint for the wholelength of the tube. Before removing the tubefrom the jig, mark both ends at the position of thewood discs with a permanent marker - to giveyou a guide line for final trimming later. Slide thetube off the jig and apply another length of cleartape on the inside of the overlapping joint.

Trim the front of the thrust tube so that it slidesover the fan shroud by about 12mm. You willneed to make 2 small ‘U-shaped’ notches in thefront edge of the thrust tube, as shown, 180degrees apart, to locate over the carbon fanmounts. It is easier to install the thrust tube ifyou leave the front edge a bit longer on theupper side of the shroud than on the bottom, andmake sure there are no sharp corners.

Cut an oval hole in the top surface of the tube,approx. 25mm behind the back of the shroud, forthe 3 motor wires to exit. Protect the wires byinserting one of the large grommets included inthe hardware bag, secured with thin CA.

Now slide the thrust-tube into the fuselage,


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(above) 2 cnc-milled ply discs of 89 and115mm diameter are included, together with2 sheets of mylar sheet to make thrust tubes.(below) Glue the 2 discs onto any suitable Ø12mm tube or rod, and make at least 1 bracewith 10mm thick balsa to support the overlapjoint while gluing and taping it together.

install the fan unit and slide the front of the tubeover the shroud into the final position - so thatyou can mark and cut the outlet end so that it isflush with the back of the fuselage.

The thrust tube should clear the fibreglass cloththat attaches the stab bolt insert nuts by 3 -4mm, but if there is any interference you cansand away the underside of the fibreglass with-out any risk (see arrow on photo right).

The thrust tube should be clear of the curvedsection at the bottom of the Fin spar by 2 or 3mm, but if necessary you can sand it a little forclearance.

During final assembly the inlet joiner and thethrust tube are secured to the fan shroud with apiece of duct tape, or similar.

Note: It is quite easy to insert the thrust tubefrom the back of the fuselage during normalmaintenance etc. Just use a length of round rod,or tube, to squeeze the tube into an ‘omega’shape, and then you can pull the sides togetherinto a ‘U’ shape, and insert it. Push in with thetube on the opposite side from the glued andtaped joint of the thrust-tube, so that you don’tstress it unduly. (see diagram right)


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(right) The Schübeler DS-75EDF unit installed, securedwith four M3 x 12 allen boltsinto T-nuts under the mount-ing rails - also with the inletjoiner and thrust tube inplace. You can also see theplywood tongue and T-nutthat the single M4 wing fixingbolt screws into here, whichis factory-installed for you.

Use tube to push mylar into a ‘U’ shape,on opposite side to joint.

mylar thrust tube

Clear tape both sides of overlap joint


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Horizontal Stabiliser

The one-piece stab is factory-finished for you. Itis secured to the fuselage by a 6mm carbondowel at the front, that fits into an 8mm carbontube in the fuselage, and a pair of M4 Allen boltsat the back - which screw into threaded metalinserts that have been laminated to the fuselagesides. The phenolic control horns are glued inplace, and jig-aligned, and even the cutouts forthe servos are started to save you a little time.

The stabiliser is quite thin and will only accept a15mm thick ‘wing-mount type’ servo if you wantit to fit completely flush. The servo should haveat least 4 kg torque and a strong, slop-free, geartrain. Therefore we also highly recommend theGraupner/JR DS 3328/3301 for this application.

Make up the servo mounts from 2 layers of themilled 3mm Liteply pieces, with a layer of the1.5mm thick ply strip glued to the bottom if nec-essary to match to exact height of your servos.Laminate them all together with thin CA, andthen file the slot thru’ the 1.5mm ply (if used) tomake sure the servo fits absolutely flush againstthe upper skin of the stab. Sand a small groovein the top of the mounts for the servo extensioncable exit. Screw the wing-mount brackets of theservos to the mounts using the small Ø 2.2 x10mm sheetmetal screws supplied in the hard-ware packs, and sand off any excess that comesthru’ the top surface of the mounts. Then removethe screws and apply 1 very small drop of thinCA to all of the screw holes - which will hardenthe wood around the edges of the hole to give amore secure fixing. Use this technique on allscrew fixings into Liteply throughout the plane.

Note: The aileron servo mounts are made up inexactly the same way, if you are also using JRDS3328 or 3301 wing-mount type servos.

Fit a JR heavy duty servo arm to each servo,and centre them now with your R/C so that theywill be at 90 degrees to the bottom surface of thestab. Apply masking tape to the bottom surfaceof the stab and mark on the lines of the linkages,in line with the elevator horns and exactly paral-lel to the fuselage centreline.

There are factory-made cutouts in the underside of the stab for the servos, but these will proba-

(above) Shape the servo mounts to fit againstthe rear spar in the stab.(below) Align servo output arm carefully withthe phenolic elevator horn, parallel to thefuselage centreline.

bly need to be enlarged a little, depending onyour servo choice. Do not cut through the car-bon rovings on the top and bottom edges of thebalsa spars if you enlarge these servo hatches.

Sand the front edge of the forward servo mountso that it is only 4 - 5mm wider than the servo,so that the servo is positioned as far forward aspossible in the stab, where the profile is thickest.Check for a good fit against the back of the for-ward spar. Then mark where the back mountneeds to be sanded at an acute angle to clearthe rear spar, and sand it to fit also. Check thatthe servo output arm is exactly in line with thefuselage centreline and elevator horns.

Carefully prepare the insidesurface of the foam sandwichfor gluing, by sanding lightlywith 120 grit and cleaning offany dust with a little Acetone orequivalent (eg: Lighter fuel).Glue the complete servomount assemblies into thestab using a little slow epoxyand micro-balloon mixture -being careful not to use toomuch or you will glue the ser-vos in also! When cured,remove the servos and rein-force all joints with a small filletof epoxy.

Run the 2 short servo extension cables out thru’ the top surface of the stab, just inside the edgesof the fuselage, using the 6mm rubber grommets supplied. Open them up with needle-nosed pli-ers to get the connectors through them. Make up the linkages from the M3 x 60mm threadedrod, M3 nuts and steel clevises as shown. Test the servo travel, throws and centering, not for-getting to add a drop of Loctite to one end. The clevise on the linkage needs to be in the holethat is 16mm (5/8”) from the centre of the servo. Cut the servo covers from the painted fibreglass sheets supplied in the kit, and secure them tothe stab surface with clear tape as shown.

Make up the extension lead needed from your servo to the nose area, for RX connection, androute it down the side of the fuselage to the nose area now.


15

(above) The servo cables exit close to theside of the fuselage, thru’ plastic grommets.(below) The servos are covered with the pre-painted fibreglass sheet included, securedwith clear tape as shown here.


Wing

The wing is also 99% factory-completed for you.All wing fixings are completed, phenolic aileronhorns are jig-installed, and the elastic-hingedspeedbrake is already cut out in the front of thewing centre-section. Strong laminated plywoodlanding gear mounts are installed during themolding process, and carefully integrated withthe wing structure.

The cutouts for the retractable landing gear andaileron servos have been made at the factory foryou, also to facilitate our Structural QC inspec-tions, but you may need to enlarge them slightlyby trimming or sanding the edges to suit yourchoice of gear.

The wing is fixed to the fuselage with a pair of6mm diameter carbon dowels at the front, whichfit into carbon tubes in the fuselage, and a singleM4 x 20 allen bolt at the back that passes thru’a 6mm thick ply tab in the fuselage and into anM4 T-nut. The wing fixings are totally completedat the factory for you.

AileronsThe wing is thick enough to install full-size ser-vos, but it is not necessary on this EDF jet, andwould only add weight, cost and increase thecurrent drain on the receiver battery.

We highly recommend that you chose similarservos to the elevators, of at least 4kg (55oz/inch) torque, such as the JR/Graupner 3328or 3301’s - and the wing-mount servo typemakes installation easy also. You could fit any‘normal-mount’ mini-servo (eg: JR3401), butthen you will have to modify the servo mountingslightly as shown on the next page.

Install the 2 aileron servos first, making up theservo mounts from the milled plywood parts and1.5mm strip in the same way as the elevator ser-vos. This time it is the front face of the frontservo mounts that need to be sanded at anangle to match the back of the main spar, keep-ing the servo output arm exactly in line with theaileron horn, and parallel to the fuselage centre-line. Keep the servo bracket at least 6mm backfrom the spar to make sure that the servo arms

16

(above/below) Shape the front servo mountto fit against the spar. Glue securely to thewing skin, spar and plywood rib with epoxy.

(below) Completed aileron linkage shown.

6 -7mm

don’t hit the spar at 45° throw.

If you chose to fit servos without integral wing-mount brackets, you can just add a couple ofextra milled liteply pieces to increase the mountheight to flush with the top of the servo, and thensecure using the small screws thru’ a small stripof the 1.5mm plywood (see photos right).

Fit a heavy duty servo arm to each servo, andcentre them now with your R/C so that they willbe close to 90 degrees to the bottom surface ofthe wing.

Prepare the surfaces for gluing by sanding andcleaning, and glue the complete servo andmount assemblies into the wing with a little slowepoxy and micro-balloons mixture, firmly againstthe main spar and also against the plywood ribthat is on the outside of the landing gear mount.When cured, remove the servos and then rein-force all the joints with a small fillet of epoxy.

The servos will need extension cables of about275mm (11”), so that they can pass through oneof the milled cutouts in the main spar, and thento the centre section of the wing, and finally intothe fuselage for approx 125 mm. Tape the exten-sion cables and connectors in place so that theycannot come loose, or foul the aileron linkages.

Carefully drill and file the slots in the bottomwing surface, just behind the servo cutouts, forthe pushrods to exit and connect to the aileronhorns. Make up the aileron linkages from thehardware supplied, using M3 x 65mm all-thread-ed rods, M3 nuts and steel clevises. Loctite theclevise onto the aileron end of the linkage afteryou have set up you have set up your linkagesand throws, as this removes the need for an M3locking nut here - which would need a much big-ger slot in the wing for clearance.

After the landing gear is completed, the retractunits and aileron servos are covered using thethin painted fibreglass sheet supplied in the kit,fixed with clear tape, in the same manner as forthe Stabilisers.

SpeedbrakeThe speedbrake is elastic-hinged in the laminat-ing process, and is already cut free for you. It is


17

Hinge Axis

(above/below) Alternative mounting methodfor servos without integral ‘wing mount’ lugs.

very effective, and is needed on landing as thespecially designed wing profile for the Spark hasextremely low drag at high loads - and the planetends to float on and on if you don’t use it.However, that fact is very useful to know if yourun out of power during a flight and need to glideback to the strip ! In production kits the speed-brake is 10mm deeper than shown here.

Open the speedbrake and mark a centreline onit, for attaching the phenolic horn. Scuff the areaon the centreline and the gluing area on the phe-nolic horn, and tack glue the horn to the speed-brake with just 2 very small drops of thin CA, asshown. Note that the small milled notch in thebottom of the horn should be in line with thehinge axis! When the speedbrake assembly iscompleted, and the throws checked, you mustreinforce the joint between the phenolic hornand the speedbrake with a good fillet of 30minute epoxy and micro-balloons.

Cut 3 pieces of the narrow clear fibreglass stripand glue them inside the lower wing skin on theback and sides of the speedbrake opening toform a 3 - 4mm wide lip. Sand the fibreglassstrip, and inside the wing, carefully and glue thestrips in place with a little thin CA. Make sureyou don’t deform the shape of the wing whiledoing this.

The speedbrake is designed to be controlled bya standard sized servo of minimum 5kg torque.If you are using JR servos then items such asDS5391, 5491, 8231, or 8311 are suitable. Theservo should be mounted onto the milled com-posite plywood-fibreglass plate, using the 2 alu-minum angle brackets and M3 bolts supplied,and then the complete assembly is glued intothe wing - against the upper surface of the wing.It is possible to remove the servo for mainte-nance, but it is quite tricky and needs a smallhole making in the wing center section for allenkey access - so we recommend that you double-check the installation and servo centering care-fully before gluing it into position.

First secure the servo, loosely, to the 2 alumini-um brackets using the M3 x 12mm allen boltsand washers as shown, into the threaded holes.Then secure the 2 angles to the milled plywoodplate, from the underside, using the M3 x 8mmbutton-head bolts. Tighten these firmly first, and


18

(above) Shape the balsa strips on the bot-tom of the mount to fit the curved wing skin.(below) View of the open speedbrake, alsoshowing servo extension cables and Rx anten-na (yellow) extension in the wing.

then tighten the 4 bolts that secure the servo.

Because of the curved shape of the upper wingskin in this area you need to glue a couple of 5x 5mm balsa strips to the bottom of the ply plateand sand them to fit the wing skin, as shown inthe photos. Fit a heavy duty JR servo arm to theservo and centre it using your R/C. Make up thelinkage as shown, using the M3 x 40mm all-thread, steel clevises and M3 nuts. Loctite theclevise that will be clipped onto to the servo armnow. The clevise on the linkage at the servo endusually needs to go on the outer hole of theservo arm, 20mm out from the servo centre.

Adjust the linkage carefully so that the servo armdoes not go ‘over-centre’ when the speedbrakeis closed, and make it difficult to open it by handto make the Rx antenna connection whenassembling the plane.

You can make small semi-circular ‘finger-hole’cut-out in the wing skin behind the speedbraketo make it easy to open it when assembling themodel at the airfield. (see photo below/right )

Main Landing GearThe Spark was designed to use low-cost, light-weight and reliable retractable landing gear, andthe Spring Air 301’s fit this specification perfect-ly. They were used in both prototypes withoutany problems at all; one set was fitted with light-weight plastic wheels, and the other with theoptional 60mm Behotec ‘slim’ aluminum wheelsand brakes especially designed for the Spark.

It is your choice what to fit, but of course theplastic wheels (without brakes) are more thanadequate for grass airfields - whereas theBehotec wheels and brakes will be more suit-able and durable for hard runways. Both wheeltypes were fitted to the standard Ø 4mm wirelegs supplied with the Spring Air set. The SpringAir 301 ‘Firewall set’ and the Behotec wheels &brake set are both available from Composite-ARF as options.


19

(above) A small hole allows access to rearservo bolts with a long ball-driver if necessary.(below) Wing is fixed to fuselage by a pair of6mm carbon pins at the front. Wrap the servoextension leads & air tubes together to makeit easier to insert them into the fuselage cableduct when fitting the wing for flying.

(below) View of Landing gear installed.

The main retract units should be secured to theintegral plywood mounts using the M3 x 12mmallen bolts and T-nuts supplied, in the usual way.You can trim the bottom wing skin a little morearound the retract openings, if necessary, to getthem into position. Use a straight edge to makesure that both units are exactly in line with eachother, and also centred on the cutouts in thewing skin that are already made for the wheels(which can be enlarged a little as needed).

Fit the retracts as outboard as possible, to givethe maximum leg length - and therefore thebiggest rotation angle before the stabiliser tipstouch the runway. For the same reason, onlyleave a minimum of 10 - 13mm space betweenthe retracted wheels in the centre of the wing.

Drill Ø 3mm through one of the mounting holesin the retract unit, and insert one of the M3 x 12allen bolts to hold it in position. Then drill theother 3 holes, also inserting a bolt to keep thecorrect alignment after each hole is drilled.Remove the retract unit and open up all theholes to Ø 4.5mm for the M3 T-nuts. Using a M3bolt and a large washer, pull the spikes of eachT-nut into the top surface of the mounting railsjust a little, with a drop of 30 minute epoxy oneach. Re-install the retracts and tighten all fourbolts, which will make sure that the T-nuts areperfectly aligned when the glue has cured.

Fit the Ø 4mm wire legs to the retracts, with thecoils oriented as shown in the photo here. Onlyfile a very small flat spot on the legs for the setscrew to sit against. Make a small semi-circularcutout behind each leg to accommodate the coilwhen the legs are retracted.

If you chose to install plastic wheels, then youneed to bend the legs to form the axles in theusual way, solder a Ø 4mm washer to the leg onthe inside of the wheel, and secure the outsidewith a Ø 4mm wheel collar, or similar. Note thatthe wheels are fitted on the outside of the legs,and are completely hidden in the central sectionof the wing when retracted.

If you have the optional Behotec aluminum wheels and brakes, then proceed as follows:Clean the wire legs well with green Scotchbrite or fine sandpaper in the approx. position that theaxles will be fitted, and degrease both parts using Acetone or equivalent. Fit the bolt-on axles tothe legs loosely, and slide the brake units onto these, followed by the short Ø 6mm aluminumtube spacer included, and then the wheels and finally the ‘E-clip’ that retains the wheels onto the


20

(above) Maintain at least 10mm of wing skinbetween the 2 main wheel wells. Balsa scrapsused to retain tubes are seen here.

(above) The Spring-Air 301 ‘Firewall’ retractset fits the Spark perfectly and is available asan option directly from Composite-ARF.(below) The optional Behotec ‘slim’ wheel &brake set also includes 3 bolt-on axles and acompact combined retract/brake valve that isdesigned for air-in/spring-out systems. Wheelsare 60mm Ø and double ball-raced.

axles. Retract the legs to check for the exactposition that the axles need to be secured to thelegs, and then tighten the set screws in the endsof the axles.

Remove the legs from the retract units and alsothe wheels and brake units. Now solder theaxles in position using quality soft solder andnon-acid flux; even better is a low-temperaturesilver solder that can be used with an electricalsoldering iron (eg: Stay-Brite).

Fit the brakes with the nipples to the rear of thewheels, tape the air tube to the wire legs, andrun it through the coil in the wire leg at the bot-tom so that it cannot get ‘kinked’ during retractoperation. You can use some small scraps of the5 x 5mm balsa strip to secure the retract tubinginside the wheel wells, to make sure it cannotget caught during operation.

When finally installing the main legs and wheels,set a little bit of ‘toe-in’ on both, about 1 degreeor so, for best ground tracking and handling.

Servo and retractscovers are made insame way as for thestab; cut them fromthe thin painted fibre-glass sheet included,and tape them ontothe wing using cleartape (eg: TESA)

Collect the extensioncables from theaileron and speed-brake servos with theretract/brake air lines,and route them thru’ aplastic grommetglued into a hole onthe center-section ofthe wing.

They all need to extend into the fuselage for 125 - 150mm (5 - 6”) and can be bundled togetherin a length of ‘spiral-wrap’ to make it easier to pass them into the fuselage area when assem-bling the plane at the field.


21

(above) Order of assembly of Behotec wheelsand brakes. Don’t forget the spacer tubes!(below) Ø 6mm steel axles are bolted on,and then soldered to the Ø 4mm wire legs

Cockpit Canopy

The fibreglass canopy frame has already been trimmed atthe factory, and the fixings completed. The front is securedwith a wire through a plastic tube from the nose, the upperback end with a small plywood tongue, and the sides arealigned with 2 small phenolic tabs into slots in the cockpitflange. You can add another pair of very small tabs at thelower back corners, using the phenolic strip included, if youwish. Cut the 2mm wire to length, sand it smooth, and sol-der the brass ball from the plastic ball-link (in the hardware)onto the end of the wire. Mill a small countersink in the nosefor the ball to sit in. This method makes it quick and easy toget the canopy off, and does not require any tools on thefield.

Fitting the clear canopy is quite simple, as it is small andrigid. However the fibreglasscanopy frame is extremelylightweight, and you need tobe careful not to deform itwhen gluing in the canopy. Youcan use your own favouritemethod and glue if you wish,but here is how we do it.

Sand the inside edges of thecanopy frame carefully with120 grit sandpaper, especiallythe fibreglass joining tapes, toensure a perfect fit of thecanopy and a good gluing sur-face. Fit the canopy frame onthe fuselage and secure it withthe wire, and masking tape all around. Trim the clear canopy very roughly to size so that it is big-ger than the edges of the cutout in the canopy frame all around. There is a faint ‘cut line’ mold-ed into the clear canopies to guide you, but you definitely need to cut at least 6mm outside thatline to begin with.

Lay the canopy on top of the frame, and view from the front and back to check that it is centred.Trim as necessary. When the canopy fits inside the frame, tape it into position temporarily, checkalignment, and then accurately mark the edge of the frame on the canopy with a wax crayon.Remove the canopy and trim exactly to shape, leaving only a 6mm overlap outside the line.

Unless you are in a warm room, we recommend that the canopy is slightly warmed up with a hairdryer to prevent cracking - but be careful not to melt or deform it!

With the canopy frame still secured to the fuselage, tack the canopy into position with a coupleof very small drops of ‘odourless’ CA, at the back and front lower corners. Make some ‘handles’from strong tape (see photo) to allow you to ‘pull’ the canopy in position while you do this. Applythe glue to the inside of the fibreglass canopy frame (not the clear canopy) and then use the tape‘handles’ to pull the canopy out against the frame into the correct position.


22

(below) Tape handles on the canopy are used to pull it intoplace while tack gluing in 6 places with odourless CA.

When the canopy is tacked into the frame, and itcannot twist any more, you can carefully removethe compete canopy frame and secure theinside edge of the clear canopy with a smallbead of slow (24hr) epoxy and microballoons.Alternatively you can use a specialist canopyglue that dries clear and bonds well the the clearplastic. Whichever method you chose, makesure to secure the canopy frame in it’s final posi-tion on the fuselage while the glue dries toensure that nothing can deform.

* Please see page 29 of these instructions fordetails of cutting the cooling inlet slots andinstalling the baffle for the speed-controller.

FuselageWe recommend that you complete the remain-der of the fuselage assembly and R/C installa-tion in the order shown below.

Cable Duct:Make the route for the extension leads and airtubes from the wing by trimming away the flanges on theinside of the inlet ducts, behind the plywood bulkhead - leav-ing approx. 5mm width for strength, and protecting theedges. Split the length of silicone tube (included in the hard-ware) with a sharp knife, and glue it on to the remaining nar-row flange with a little thin CA, as shown here.

NosegearThe factory-installed nosegear bulkhead is 6mm thick lami-nated aircraft-grade plywood, with the mounting holes pre-drilled and the M3 T-nuts glued to the front face of it. Thehole centres match the Spring-Air 301 series ‘Firewall’mount, and if you chose to fit a different retract unit then youwill need to push out the T-nuts and redrill to suit the mount-ing centres of your nose unit.

Assemble the nose retract unit as shown, with the steering


23

(below) Clear canopy is trapped in place withepoxy/micro-balloons mixture. Also note theshort tube that accepts the nose fixing wire.Make sure that this is securely glued in place !

(above) Cable duct in fuselage is lined withsplit silicone tube to protect extension wiresand air lines from sharp edges.(below) Correct assembly of the Spring-Air301 firewall mount noseleg unit.

arm on the right side. File only a very small ‘flat’for the set screws in the wheel collars (in thetrunion block and steering arm) to grip onto, oth-erwise you will weaken the wire leg. Make surethat the plastic bracket slides up and down thesteering arm smoothly.

Install the retract onto the bulkhead. Fit the wingonto the fuselage, with the main gear extended,and set the plane on a level surface to set thelength of the nose gear leg. It is preferable tohave a little positive angle (+0.5 - 1 degree) onthe wing root, especially if flying from grassstrips, and we suggest that you make the nose-leg 4 - 5mm longer than the length required for0 degree wing incidence.

We also recommend that you bend the noselegback a little, at about a 5 degree angle, at about35mm (1.5”) above the axle position. This notonly improves the steering, but also makes surethat larger wheels retract completely into thefuselage.

If using plastic wheels, then bend the wire leg toform the axle for the wheel in the usual way.

If you are fitting the optional Behotec wheels,then secure the axle to the leg and solder it onas described in the wing section. There are 2very short Ø 6mm aluminum tube spacers in theset that must be fitted on either side of the wheelhub to centre it on the axle.

The steering servo installation is described atthe end of this section, as it must be installedafter the battery support bulkhead is completed.


24

app

rox.

128

mm

app

rox.

65m

m

5 - 7mm

(above) Spring-Air 301 ‘firewall’ retract boltedto the 6mm ply factory-installed bulkheadwith the M3 allen bolts and T-nuts.(below) Bend the nose leg back about 5 -7mm, starting just above the wheel, forimproved ground handling.

Speed-Controller

The ‘Jeti Spin 99’ Speed-controller is mountedright at the back of the cockpit as shown, on topof the ducting, and it is also used to secure thefibreglass Inlet joiner to the inlets, as the inletjoiner is not glued into the plane.

Please read the ‘Cooling’ section later in thismanual before installing the speed-controller, asit might affect the exact mounting of it - depend-ing on the ambient temperatures that you willoperate your Spark in.

Make up the 3 small 6mm thick mounting blocks by gluing short lengths of the 3mm Liteply striptogether with thin CA, and sand to shape to fit on the ducts. Secure the controller to the 3 blocksusing the 2.9 x 10mm sheetmetal screws thru’ the rubber mounting grommets.

Sand the gluing areas on both duct parts, and then glue the complete assembly in place using30 minute epoxy and micro-balloon mixture, keeping it exactly central in the cockpit opening. Ofcourse you should have the fan unit installed and fixed in position while you do this to ensurecorrect alignment of the Inlet joiner. See photos on page 28 and 29.

* Please see the ‘Cooling’ section on page 27, 28 and 29 for details of the air vents and cutoutsneeded for cooling the speed-controller.

Flight Battery Installation

The Lipo Flight batteries are theheaviest item in the plane, andmust be fixed very securely, asthey will weigh several times theiractual weight under ‘G’ forces.This EDF system used isdesigned to use a pair of 5Spacks of approx. 5200 mAH, asshown here, and these are avail-able from us as an option (product#865001). Of course you canchoose your own packs, whichmight be a different size or shapeto the ones shown - and in thatcase we advise you to follow thebasic design principle shown hereif you make your own battery trayand supports.

The 5200 mAH packs shownweigh 660 grams each and, whenpositioned as shown, the Centre


25

(above) View of the completed dual Lipo Flight batteryinstallation. The 2 wires with yellow heatshrink on them arejoined together to ‘arm’ the system ready for flight.

of Gravity location is almost perfect, only need-ing the small RX battery for final adjustment. Iffitting your own larger packs it is important toposition them as far back as possible in the nosearea, to maintain the correct CG without havingto add weight in the tail.

The following instructions assume that you areusing a pair of packs of maximum size 165mmlong, 45mm wide and 55mm high, which can befitted onto the milled parts supplied in the kitwithout any modifications.

Lightly sand the battery tray and make sure thatthe small tab on the tapered end of it fits easilyinto the milled slot in the rear bulkhead, which isfactory installed for you. In case you need toreposition the slot in this bulkhead to suit differ-ent shape Lipo packs we have included a smallply plate with milled slot in it, that you can use a‘doubler’ if necessary on the new slot position.

Glue 4 strips of the 5 x 5mm balsa onto the topand bottom of the battery tray where your packswill be, with thin CA, to maintain the air gap allaround the packs. They also stiffen the batterytray considerably. Secure your packs onto thetray using the double-sided Velcro band sup-plied, with the connection wires at the rear end.Do not secure the Lipos to the tray with cable-ties, because the high pressure can damagethem. Of course you can modify the battery traysa little to suit the shape and size of your packs,and we have included 2 in the wood pack.

Assemble the front support bulkhead from themilled ply parts as shown in the photo, and justtack together with a little thin CA. Check thatyour nose gear steering servo fits into the milledplywood mount, and then also glue this to thebulkhead. It is milled to fit a 15mm wide JR3341or 3328 sized servo.

The battery tray is secured to the front supportusing an M6 plastic bolt and large plastic nut,supplied in the kit. Trial fit the bulkhead in thefuselage, using your completed battery tray (withbatteries) to find the exact position it must beglued into the fuselage.

IMPORTANT ! You must leave at least 10mmclear space between the front of the lower bat-tery pack and the back edge of the horizontal rail


26

(below) Rear battery support bulkhead is fac-tory-installed. The battery tray has a milled tabthat fits in the central slot, arrowed here.

(above) The 2 packs of 5200mAH 5S Lipossecured to the milled battery tray.(below) Battery tray is secured to the frontsupport with an M6 plastic bolt & large plasticnut. Steering servo mount is glued into theslot in the right side of the bulkhead.

that the M6 plastic bolt is screwed into, becauseyou need this space to move the battery plateforward out of the rear slot, and angle it upwardsto get it out of the plane. Check this carefullybefore drilling the holes for the 6mm bolt, andgluing the front support bulkhead permanently inplace.

When you have determined the position, drill Ø5mm right thru’ the rounded tab on the front ofthe battery tray and the plywood rail on the backof the front support bulkhead, that the plasticbolt will be screwed into. Remove the tray andopen the hole out to Ø 6mm in the tab only. Usethe short M6 bolt sup-plied, or an M6 tap, tothread the Ø 5mmmilled hole in the hori-zontal rail, and thenscrew the plastic boltin from the underside.Do not glue the bolt inplace.

Make sure that thebulkhead is not tight inthe fuselage and sandas necessary to main-tain a 1 - 2mm gap allaround it for gluing.We have supplied it alittle too large to allowit to be fitted in different positions, depending onthe length of your flight packs and battery tray.

Prepare the area carefully by sanding andcleaning, and then glue the front support bulk-head into the fuselage with a thick mixture ofslow epoxy and micro-balloons, using the bat-tery plate (without the Lipo packs on it) as aspacer to ensure perfect position while the gluecures. Also glue the nose steering servo mountto the fuselage side now.

Cooling

Remember that all the waste energy dissipated by the LiPo batteries, Speed-controller and elec-tric motor that power your Spark is expelled as heat inside the fuselage. It is normally the Speed-controller that has the hardest job, and gets the hottest, and it is very important that you makeadequate provision for enough cooling air to enter, and exit, the fuselage - and make sure that itis directed over these 3 critical components, especially the speed-controller. Certainly the batter-ies must not get warmer than 50°C maximum, the Speed-controller gets warmer than this - but


27

(btm) View of underside of the front supportassembly and battery tray.

Sideview of battery tray mounting

Battery tray

Balsa stripsPlastic nut

Battery tray moves forwards & then up

Plastic bolt

Min. 10mm gap

Front supportbulkhead

it will automatically cut-off if it gets too hot to pro-tect itself anyway.

Our prototype Sparks have been flown manytimes in very warm ambient temperatures(35+°C, 100° F) with the set-up shown here, andthe temperatures of the speed-controller, flightbatteries and motor remained inside acceptablelevels with careful use of part-throttle. In moretemperate climates this set-up should have larg-er safety margin, even when using a lot of part-throttle. It is most important to make the small‘baffle’ over the top of the speed-controller tomake sure that the cooling air is directed thru’the fins of the heatsink.

We use a digital infrared thermometer to checkthe temperatures of all components carefullyimmediately after flight, and this is an invaluabletool and not expensive (available at good hobbystores that sell quality R/C electric cars). As arule-of-thumb you definitely should be able tohold the batteries without burning your fingers.Likewise you should be able to touch theheatsink of the speed-controller for several sec-onds without burning your fingers.

Speed Controller - CoolingThis is usually the most critical component, because if the temperature becomes too high duringflight the electronic sensors in the speed-controller will automatically cut the power off complete-ly until the temperature reduces, which usually only takes a few seconds - and then it will per-form normally again. This prevents damage to the speed-controller unit.

It is important to remember that the controller becomes hottest when using half-power, and thisalso reduces the cooling to the unit. It is best to adjust your flying style slightly and use a com-bination of 90 - 100% power for most of the time, and pull the throttle right back for a few sec-onds during each circuit to allow the controller to cool a little. Certainly we strongly recommendthat you check the temperature of the speed-controller immediately after landing for at least thefirst few flights, and increase the cooling airflow over it if necessary due to high temperatures.

The amount of air needed to cool the controller will also depend on the ambient temperatureswhere you will fly your Spark. The inlet cooling air enters thru’ both the nosegear opening, andalso from the small slots that you must cut on either side of the canopy frame (see below).

To provide a strong flow of cooling air over the speed-controller you can cut 2 small oval shapedholes in the top of the inlet joiner, about 25mm behind it as shown in the photo above. These are25mm long and 15mm wide. However you must install the baffle (see below) glued into thecanopy frame above the controller, to make sure that all the air entering the fuselage is suckedright through the cooling fins - and not just around and over the top of the controller.


28

(above) A digital laser Infrared thermometer isvery useful for accurately checking speed-controller & motor temperatures after flight.(below) If flying in temperate weather thesetwo holes behind the controller should pro-vide enough cooling airflow, in conjunctionwith the air inlet slots in the canopy frame

Increased CoolingIf the speed controller still becomes too warm during normal flying, or you will operate in verywarm ambient temperatures, we recommend that you use the following method to increase thecooling flow thru’ the heat sink fins on the speed-controller (see diagram below).

Increase the depth of the 3 mounting blocks by another 5 - 6mm, so that you can fit the speed-controller inverted, with the cooling fins on the bottom, making sure that they are only clear ofthe duct top surface by 1 - 1.5mm in the centre. Cut a rectangular hole (with radiused corners)in the top of the inlet joiner under the back 30 - 40% of the area of the controller. Start by mak-ing the size of the hole approx. 35mm wide and 25mm deep, and enlarge if needed. In conjunc-tion with the inlet slots in the canopy frame, and the baffle above the speed-controller, this willpromote a very strong airflow through the cooling fins.

NB: If using this method, then you do not need the 2 small holes in the duct 25mm behind thecontroller, as mentioned above, and if already cut they can be covered or taped over.

Cooling Baffle and SlotsAlthough some air enters the fuselage thru’ the nose gear opening, and travels around the bat-tery packs to cool them and then towards the rear of the fuselage, it is normally necessary tohave more inlet area than this.

We advise you to cut a pair of small slots on both sides of the canopy frame as shown, about15mm behind the clear canopy, to increase thecooling inlet air volume. As the canopy frame isvery lightweight you will need to reinforce theseareas first, by laminating one layer of 160 gramfibreglass cloth just onto the area of the slots(about 60 x 60mm).

Sand and clean the areas carefully and laminatethe cloth with slow (24 hr) epoxy resin; only justenough epoxy to wet out the cloth is needed.When the resin is fully cured, mill and file the 4slots, each approx. 6mm wide and 40mm long,


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Cooling air fromnosegear opening

Cooling air fromcanopy slots

baffle to force all airto pass thru’ heatsink

speed-controllermounted inverted, withheatsink underneath

hole in duct approx.35mm wide and25mm deep.

Increased Cooling Airflow

parallel to the back of the canopy opening. If youwish you can reinforce the narrow stripsbetween the slots with one carbon roving, asshown. We have included some 160 gram fibre-glass cloth and carbon roving in the hardware.

The baffle is designed to force all the inlet air topass thru’ the cooling fins on the heatsink -rather than just passing it by without doing anycooling, as the air will take the easiest route.

Glue a length of the 5 x 5mm balsa strip acrossthe canopy frame, about 5 or 6mm above the centre of the speed-controller, being careful notto deform the canopy frame. Cut a semi-circularshaped piece of the thin fibreglass sheet (includ-ed in the hardware pack) and glue it into thecanopy frame at an angle of about 30°, asshown, extending past the balsa strip so there isonly a 1mm gap between it and the speed-con-troller cooling fins. Tack these parts in positionwith a little CA, and when finalised reinforce thejoints with a very little 30 minute epoxy andmicro-balloons mixture. Remember to keep theweight down at the front of the plane.

Flight batteries - CoolingThe Lipo batteries don’t normally have too muchof a problem getting hot, and we have not hadour packs become more than 10 - 15 degreesabove ambient air temperature after a longflight. However, if you do overheat them they willbe permanently damaged, so it is wise to checkthem carefully after the first few flights. If youcannot hold the packs, comfortably, in your handafter flight then they are too hot! Battery temperature should not exceed 50° C.

Install them on either side of the milled plywood tray that we include (not forgetting the 5 x 5mmbalsa strips under each pack), with at least 8 - 10mm of clear space all around them, then theair entering the fuselage through the nosegear opening is more than enough to keep these coolwhen used normally. The air continues backwards in the fuselage over the speed-controller, andexits both through the slots cut in the inlet joiner behind (or under) the speed-controller - and alsoaround the outside of the thrust tube and out of the top of the back of the fuselage.

Remember that the cooler your batteries run, the longer the life-cycle of them.

Motor - CoolingThe fan motor already has well-designed cooling flow through the vents in the engine mount andthis normally provides enough to prevent any chance of damage to the motor due to over-tem-perature. However, we also recommend that you check the motor after the first few flights tomake sure that it is not getting too hot. The rear bell of the motor should never exceed 75°Celsius. The infrared thermometer makes this an easy job!


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(above) Cut 4 cooling slots in the sides of thecanopy frame, reinforced as described, tomake sure there is enough airflow over thespeed-controller.(below) A simple baffle plate to direct the airthru’ the heatsink cooling fins, made with thethin fibreglass sheet included, helps to keepthe temperatures in check.

Nose steering servoThe nose gear steering servo is normally fittedinverted on the milled plywood mount that youhave installed, but if you want to use a single RXchannel to control Rudder and Steering, thenyou must mount the servo the other way up.

We used a JR 334 in the prototypes, and that ismore than strong enough - and very lightweight.Fit the shortest standard servo arm, centre itnow with your R/C, and screw the servo to theply mount with the normal screws.

The steering pushrod is made using the M2threaded rod and M2 steel clevises included.Cut to length and solder one clevise onto theretract steering arm end, and the M2 nut andother clevise onto the servoend. Fit the clevise into theinner hole in the servo arm, asonly a small throw is needed.

Now retract the nose gear,making sure that the wheelstays centred and straight.Take the small milled liteplysteering support and file a2mm wide slot in it that corre-sponds to the height of thesteering push rod when thegear is retracted, and make alightening hole. Tack glue to the side of the fuselage, as shown in the photo, with one drop of CAand check for correct operation. When correct, glue it in place with thick CA, or 5 minute epoxy.

This small support will make sure that the nose wheels stays centred when retracted, and there-fore comes down every time for landing, so don’t forget to install it !

Receiver and Switch plate

Included in the kit are the 4 milled parts to makeup the removable receiver plate, as shown in thephoto here. The small tab on the front of it slidesinto the slot in the sub-bulkhead, which you glueinto the nose, and the rear is secured onto 2small plywood tabs on the front battery supportbulkhead with M3 bolts and T-nuts.

This plate is designed to only have the RX andswitch on it, to keep the front of the plane verylightweight, and it is recommended to install theRX and the antenna as far away from theSpeed-controller and motor as possible to pre-


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(above) It is important to fit the small supportplate for the steering pushrod, so that thenosewheel stays centred when it is retracted.(below) A view of the steering support fromthe underneath, also showing the nosegearsteering servo, which is mounted inverted.

(above) Milled liteply parts for the Receiverand Switch plate. The front of the plate fitsinto a slot in the bulkhead, which is gluedinto the nose, and the back is secured withtwo M3 bolts and T-nuts.

vent any possible interference.

Fit your receiver and switch to the plate asshown, with a small foam pad under the Rx, andmake cutouts to save as much weight as possi-ble. Installed here is the Powerbox Digi-switch,which is an ic-controlled electronic switch (whichfails ‘ON’) that has a built-in linear voltage regu-lator (to 5.5 volts) designed specially for use with2 cell (7.4volt) Lipo batteries for the receiver.The single LED glows in 4 different colors andsequences to indicate the status, including a lowbattery warning, and is highly recommended. Itis available from C-ARF as an option (Product #960610)

Glue the 2 small plywood tabs into the milledslots in the top of the battery support bulkheadwith epoxy. Fit the Rx plate into the slot in thefront bulkhead, and insert into the fuselage ashown. With the fuselage upside down, reachthru’ the nose wheel opening and tack glue thebulkhead to the nose, and then remove the Rxplate and reinforce the joint with a little 30minute epoxy and micro-balloons. Reinstall theRX plate and drill the two Ø 3mm holes throughthe rear tabs. Open the holes in the plywoodtabs on the battery bulkhead up to Ø 4.5mm andinsert the T-nuts with a little 5 minute epoxy.Reinstall the Rx plate and bolt into position,using the M3 bolts and washers to set perfectalignment of the T-nuts before the epoxy cures.

RX AntennaThe location of the RX antenna is your choice,but in any case a very careful range check mustbe carried out before flying your Spark, both withthe motor running and off. Electric models arealways more critical in this respect, and it is mostimportant to keep the antenna as far away fromthe motor and speed-controller as possible.

If using a ‘normal frequency’ receiver (eg:35MHz or 72Mhz), with a full-length wire anten-na, we strongly recommend that it is installed ina ‘L-shape’ and kept as far away from any pos-sible RF or EMI interference by installing part ofit in the leading edge of the wing. On our proto-types we cut the antenna, and soldered onminiature gold connectors at the junction whereit enters the wing. We ran the antenna along theside of the fuselage (opposite side from all the


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(above) Receiver and Switch plate installationis easy and neat using the milled liteply parts.(below) The Rx antenna was cut at the wingseat, had a small gold connector soldered toit, and is connected to the remainder in atube in the wing leading edge when assem-bling the plane at the field.

servo cables), on the outside of the inlet, downto the front of the wing opening. Here we cut theantenna, leaving about 75mm extra before sol-dering on the plug, and this is inserted into thewing thru’ a small plastic grommet when assem-bling the plane, and connected to the other partin the wing. In the wing we glued a plastic outersnake, supported on a liteply tab, in the leadingedge and slid the remaining antenna inside it.(also see page 18)

Don’t forget to reach in thru’ the speedbrakeopening & connect the antenna when putting thewing on at the airfield !!

Another alternative would be to use the 2.4 GHzradio system.

Note: The additional miniature connector sol-dered close to the Rx in our plane is because weoften have to change the Rx to different frequen-cies for Demos in several countries.

Retracts and ValveConnect the retracts following the manufactur-ers instructions in the usual way, and fit a singlequick-connector to the tube that comes out ofthe wing with the servo extension cables. Ofcourse, if you are installing the optional Behotecwheels and brakes, then there will be 2 airtubes, and you can use the compact combinedbrake and retract valve that is included in theset, so that you only need one servo to operateboth systems. The air tank can be glued to theside of the fuselage on one side of the inlet join-er using double-sided foam tape.

We mounted the Spring-Air retract valve with amini servo (JR 3341) on a small liteply plate inthe fuselage on the other side of the inlet joiner,using some self-adhesive velcro pads so that itis easily removable. Included in the kit are the 4milled liteply parts to make up the retract servomount, as shown here, and they can be gluedtogether with thin CA.

Extension leads etcEven though this is an electric model, and there should be no vibration, we highly recommendthat you install the plastic grommets that we have included (or equivalent) in all positions wherewires can rub against the edges of composite or fibreglass material, as it can easily cut throughthe insulation of important servo leads or electrical cables. The photo of Rx antenna location(above) shows the 2 grommets installed in the top of the wing.


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(above) Retract valve & servo mounted onsmall milled liteply plate, and secured to thefuselage side with double-sided velcro pads.

(below) All servo extension leads are on theopposite side of the fuselage to the RX anten-na. The extension leads and air tube for con-nection to the wing are shown here.

(below) The Rx antenna in the wing is in aplastic tube in the leading edge.

Rx BatteryThe receiver battery is positioned to set theexact CG of the model, and in our prototypes itneeded to be installed just behind the EDF unit.

We used a 1500mAH 2 cell Lipo pack (7.4 volt),which only weighs around 70 grams, and fixed itsecurely to the bottom of the fuselage, under thethrust tube. An extension cable is then routedalong the fuselage side to the Digi-switch in thenose. Typical current draw from these small ser-vos for a 5 minute flight is less than 80 mAH.

Disconnect the Rx Lipo battery from the Digi-Switch when the plane is not in use.

EDF Connections and Operation

The Schübeler DS-75 fan unit and the Jeti Spin 99 speed-controller come pre-wired for you, atthe correct length for this set-up in the Spark. The gold connectors are already soldered on tothe correct length wires for you; the 3 connectors between the speed controller and fan motorare Ø 3.5mm, and the ones on the Lipo packs and input to the speed controller are Ø 4mm.

The Speed-controller has one long JR-type extension lead from the front of it, which must beconnected to the throttle channel of your RX, using an extension cable. The other (shorter) cablefrom the controller has a red plug on the end of it, and this is for connecting to a Jeti-Box displayterminal that can display various data, and adjust motor timing etc. When not in use we suggestthat you apply a small piece of tape over this red connector to prevent accidental short circuits.

The 3 black wires from the motor run along the top of the inlet joiner and plug into the 3 color-coded (red, yellow and black) wires of the speed-controller. It does not matter which of the blackwires is plugged into which color wire of the controller the first time, but if the fan unit runs inreverse the first time you switch it on, then you must swap any 2 of the 3 wires to reverse the


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(below) A 2 cell Lipo of about 1500mAH isenough for the RX power, as the small servosdraw very little current.

rotation direction. After that youshould always make these 3 con-nections in the same orientation,and you can slip short lengths of col-ored heatshrink over the the blackwires to mark this for the future.

The two 5S Lipo cells are connectedtogether (in series) to provide a 10cell pack (37 volts). Connect thenegative (black) cable from one ofthe flight packs to the black cable onthe front of the speed-controller.Connect the positive (red) cablefrom the other pack to the red cableon the front of the speed controller.

The remaining red and black cablesare connected together for flight,using the short ‘jumper’ cable (sup-plied) with the male 4mm gold con-nectors on both ends. This is, ineffect, the ‘arming’ cable that switch-es ‘on’ the EDF system, and is thelast cable to be connected beforeevery flight, and disconnected immediately after-wards. Make this final connection quickly - oryou will get small spark, which is not dangerous- but can cause you some ‘surprise’ the first timeit happens!

When the system is correctly connected andarmed you will get a short musical ‘chime’ fromthe speed-controller to confirm that everything isOK. Be extremely careful carrying and transport-ing charged Lipo cells, and at least one of theconnectors on each battery must be taped over,or protected, so that it is not possible to cause an accidental short circuit.

Make sure that the throttle stick on your transmitter is at the ‘idle’ position when arming the bat-teries and connecting the power system, and secure or have a helper hold the plane. Until theJeti 99 speed-controller has recognised that the Tx throttle stick on has been set at ‘idle’ it willnot power up the system, for safety reasons.

Battery ChargingPlease exercise extreme caution when charging Lipo batteries, and strictly follow the batterysuppliers instructions. Never charge the Flight battery packs in the plane.

Normally Lipo cells must not be fully discharged, or they will be damaged forever, and should notbe charged at more than 1C. Therefore a 5200mAH pack must not be charged at more than 5.2Amps. Aim not to use more than 80% of the capacity of each pack - for example if using 5200packs you should not need to recharge more than 4150mAH each time.


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(above) View of the battery & speed-controller connec-tions. The positive and negative wires from the Lipos withyellow heatshrink on them are joined together to switchon (or ‘arm’) the EDF system ready for flight.(below) View of the finished Rx & Digi-Switch installation.

Inspect your batteries regularly to make sure they are not damaged, and have not expandedanywhere. Be careful not to drop them or puncture the outer surface, which will damage themirrepairably.

Certainly we strongly advise that you use a quality charger, and balance the Flight packs at leastevery 2nd time that they are charged using a high-quality balancer with a safety cut-off.

We use the Orbit Microlader Pro (available from C-ARF as product #961200) and a pair ofSchulze balancers and charge the packs in series as a 10S cell. Quality balancers are availablefrom many sources, including Orbit, Graupner, Schulze, Emcotec etc.

Setting Up Your Spark

Centre of Gravity: Set the Centre of Gravity at 145 - 150mmback from the front edge of the centresection of the wing. At this position itshould balance slightly nose-down.

Don’t forget to balance the plane lateral-ly also, and if needed add a small weightinside the light wing tip.

Control Throws:All throw measurements shown beloware made at the root/trailing edge posi-tion. We did not find it necessary to usedual rates, but instead added someexponential to all main flight controls.

These throws are not too sensitive, andyou can fine-tune them to your personalpreference after the trimming flight.

ElevatorElevator throw should be about 16mm ‘up’ and 14mm ‘down’, with 30 - 40% exponential.

RudderRudder throw should be about 25 - 28mm both sides, with 25% exponential.

AileronsAileron throw should be about 13mm ‘up’ and 15mm ‘down’, with 40% exponential.

The reversed differential is to take into account that the hinge line being in the top skin insteadof on the centre line, so the aileron gets a little smaller as it moves down.


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CENTRE of GRAVITY

C of G range: 145 - 150mmfrom front of wing at centre.

150mm

During take-off and landing both ailerons can be lowered 5 - 8mm, at the root, to act as ‘flaper-ons’ if you wish.

Speed brakeThe speedbrake should open at least 80 degrees, and 90 degrees is possible. We set it on aslider on the Transmitter for easy adjustment - depending on the wind conditions.

You can also open the speedbrake about 20 degrees during take-off, which helps the plane torotate at slower speeds.

Flying the Spark

The CARF Spark is designed for powerful jet-flying with both electric and turbine propulsion. Itis not a "compromised EDF", where absolute light weight allows you to fly "low cost" with mini-mum power, at the expense of rigidity and overall performance. It is a full blown Jet airplane, andcan be flown as such.

The structural integrity and aerodynamic design allows speeds up to 200 mph (320 km/h) withboth electric ducted fan and turbine. The control surfaces in size and deflection are well adjust-ed to such flying, thus the Spark handles the different speeds very smoothly. At the slowestspeeds with high angles of attack it is still very controllable with the quite small control surfaces,and at high speeds it does not feel "twitchy" at all. Despite its small size it's the smoothest flyeryou can imagine throughout the whole speed range - which is very wide.

The airfoil was developed by Robert Vess in the US for scale model race planes. Its minimumdrag at high loads made us choose this airfoil for the Spark. Large stab surfaces make the Sparkan uncritical flyer. The wings’ geometry with the low drag tips accounts for the Spark's agility andperformance.

Aerobatic performance is unlimited. All kinds of rolling maneouvers are easy, vertical maneou-vers are breathtaking due to the huge propulsion power we designed the Spark for. Even snapswork great, but one must keep in mind that with such a small plane at such high speeds the snaproll rate is unbelievable, therefore only the most experienced pilots should attempt snap rolls atall - especially because it puts the highest possible stress on the airframe, if not done correctly.

Takeoffs and landings are easy, the plane tracks perfectly on the ground and slows down nicelywith the speedbrake. For slower take-off and landing speeds the ailerons can be lowered 5-8 mmat the root. This increases the lift of the wing and slows the plane down, without making it criti-cal. Also a 20% extended speed brake helps to rotate the plane during take-off at slower speeds.With the speedbrake fully deployed, the plane still needs to be brought in with a quite high angleof attack to slow it down for small flying fields. So, don't worry about slowing the plane down andgetting the nose up in the last turn, even before the final approach.

When we test flew the first prototypes we found the performance and agility that we hadn’t evendreamed of. You will love the flying characteristics of the Spark - that's our promise to you.


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(above) A couple of views of the 1st prototype, taken just before the extremely suc-cessful test flights. This is similar to the production ‘Prototype’ paint scheme.

(left) A nice fly-by with a pre-production Spark, owned andflown by one of our UK Reps,Dave Wilshere of Motors andRotors.

Appendix: Kit Contents: SPARK Kit

Quantity Description 1 Fuselage1 Wing 1 Fibreglass sheet, painted (servo cover set)1 Stabiliser1 Linkage cover, painted (for Rudder)1 Canopy frame (fiberglass)1 Clear canopy2 Thrust Tubes (pre-cut mylar sheet)1 Inlet Joiner (fibreglass)1 Set of Protection bags (wings, stabs and rudder) 5 pieces1 Hardware bag1 Milled wood parts bag1 Instruction Manual (English)

Hardware PackFuselage bag

Quantity Description 1 Hinge Wire, Ø 2 x 500mm (canopy fixing)1 Ball-link, Plastic, 2mm (canopy fixing)4 Allen bolt M3 x 12mm (nose retract fixing)2 Allen bolt M3 x 12mm (RX plate fixing)2 T-nut M3 (RX plate fixing)2 Washer M3 (RX plate fixing)1 Velcro band, double-sided, 18 x 650mm (RX & battery fixing etc)1 Bolt, Plastic, M6 x 25mm (battery plate fixing)2 Nut, Plastic M6 (battery plate fixing + 1 spare)1 Allen bolt, M6 x 20mm (to thread hole for plastic bolt)1 Pushrod, M2 x 150mm (nosegear steering)2 Clevise, steel, M2 (nosegear steering)1 Nut, M2 (nosegear steering)1 Silicone tube Ø 6 x 300mm (cable protection)1 Grommmet O.D. 14mm (cable protection)1 Grommmet O.D. 6mm (cable protection)3 Sheetmetal screw Ø 2.9 x 10mm (to secure Speed-controller)6 Allen bolt M3 x 12mm (EDF fixing + 2 spare)4 Washer M3 (EDF fixing)4 T-nut M3 (EDF fixing)1 All-thread, M3 x 60mm (rudder linkage)2 Clevise, steel, M3 (rudder linkage)1 Nut, M3 (rudder linkage)1 Fibreglass cloth 160 gm 100 x 150mm (canopy frame reinforce)1 Carbon Roving x 400mm (inlet reinforce etc)1 Fibreglass band 20 x 250mm (reinforcement)1 Phenolic strip 15 x 50mm (extra canopy frame alignment)1 Wheel collar I.D. 4mm + set screw (nosewheel retaining)


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Wing bagQuantity Description2 Allen bolt M4 x 20 (wing fixing bolt + 1 spare)1 Washer, M4 (wing fixing)1 Phenolic horn (speedbrake horn)1 Servo mounting plate for speedbrake (1.5mm ply/fibreglass)1 Aluminum angle bracket, left (speedbrake servo mounting)1 Aluminum angle bracket, right (speedbrake servo mounting)4 Allen bolt, M3 x 12mm (speedbrake servo mounting)4 Washer, M3 (speedbrake servo mounting)4 Button-head bolt, M3 x 8mm (speedbrake servo mounting)1 All-thread, M3 x 40mm (speedbrake linkage)2 Clevise, steel, M3 (speedbrake linkage)2 Nut, M3 (speedbrake linkage)14 Sheetmetal screw Ø 2.2 x 10mm (wing-mount servo fixing + 4 spare)2 All-thread, M3 x 65mm (aileron linkages)4 Nut, M3 (aileron linkages)4 Clevise, steel, M3 (aileron linkages)8 Allen bolt, M3 x 12mm (retract fixing)8 T-nut, M3 (retract fixing)2 Wheel collar I.D. 4mm + set screws (wheel retaining)1 Grommmet O.D. 14mm (cable protection)1 Grommmet O.D. 6mm (cable protection)

Stabiliser bagQuantity Description2 Allen bolt, M4 x 20m (stab fixing bolts)2 Washer, M4 (stab fixing)4 Clevise, steel, M3 (elevator linkages)4 Nut, M3 (elevator linkages)2 All-thread, M3 x 40mm (elevator linkages)8 Sheetmetal screw Ø 2.2 x 10mm (wing-mount servo fixing)2 Grommmet O.D. 6mm (cable protection)

Available Accessories:(please check our website for current list of options and accessories)

Schübeler DS-75 EDF unit & speed-controller setSet two HDHE Lipos 5200 mAH

Powerbox Digi-SwitchOrbit Microlader Pro Lipo charger

Spring-Air 301 Firewall setBehotec ‘slim’ Spark wheels, brakes, axles & valve set

Turbine upgrade set (check website for availability)


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Standard Wood parts included in the kit

Fuselage hardware pack Wing hardware pack

Stabilisers hardware pack


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EDF set (item #864003)Schübeler DS-75 with motor installed, & Jeti Spin 99 Speed-Controller, all wired.

OPTIONAL ITEMS

Flight battery set (item #865001)two 5200mAH 5S Lipo packs, wired.

Wheels and Brakes set (item #740550)Behotec Ø 60mm wheels, brakes, axles

and retract/brake valve

Turbine Upgrade Set

Landing gear set (item #740500)Spring Air 301 ‘Firewall mount’ set

AVAILABLE LATER.Please watch our website

for news of this item.

Mike C (27 Sept 2007) - version 1.0

Instruction Manual Composite-ARF SPARK - michel … SPARK [email protected] Instruction...

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Transcript of Instruction Manual Composite-ARF SPARK - michel … SPARK [email protected] Instruction...