KAVAN Dingo A3 glider kit 796mm - Instruction manual
Introduction
The A3 glider DINGO is a great entry level kit for any modeller who has already gained some skills in the classic balsa bashing and dope&tissue covering. You will need some basic modeller's tools, glues and dopes – you will find these handy with any of your future projects as well. Please make yourself familiar with the building plans and this manual BEFORE you actually start the assembly.
Before you start
Glue: You can use acetone based modeller's glue (UHU Hart etc.), water-resistant white glue (KAV9960 KAVAN White Glue, BISON Super Wood etc.) or medium cyano (Power CA, KAV9952 KAVAN Medium CA etc.).
Dope: KAVAN Classic line Adhesive dope (KAV9987), Shrinking dope (KAV9986), Top gloss dope (KAV9989) and Thinner (KAV9990) are the must for the dope and tissue covering, indeed.
Tools and accessories: You will need a perfectly flat building board (at least 300×700 mm), modeller's knife (Excel K1 w. no.11 blades etc.), jigsaw, sanding blocks with 180 and 360–400 grit sandpaper, model hobby pins, scissors, sharp model hobby knife, flat and round fine file, soft flat (1/4"–3/8") brush, thin clear plastic film to protect the building plan (a large PE bag cut in half will work).
Precautions
The model you build and fly is not a toy! Although it may seem light and slow in flight, it is capable of causing injury or other damage if mistreated. It is up to you whether you build the model properly, fly properly and continue to fly in accordance with common practice and rules (and common sense). If you are just getting started with aircraft models, ask for advice from your model shop or an experienced modeller at your local modelling club to find a good instructor.
Before construction: Build the model exactly as instructed. Do not change or modify the model. If you do, you risk that the model may be unsafe or unable to fly. Take the time to build everything firmly and reliably. Use appropriate tools, accessories and other equipment that is in top condition. Correctly install all parts of the model and check the model before the first and every subsequent flight.
Specification
| Wingspan | 796 mm |
| Length | 655 mm |
| All-up weight | 150 g |
Assembly
- Lay the wing building plan on the building board and put a sheet of a thin clear plastic film to protect the building plan. If you have got just a small building board, you can carefully cut the building plan into sections – wing section, horizontal tailplane section etc.
- Before you apply the glue, please, always double-check the correct size, shape and alignment of the particular part.
- Balsa and spruce sticks are intentionally supplied oversized in the kit. Pin the stick to the plan overlapping at both ends – you will cut/sand them to the correct length/shape once the assembly of the particular part has been finished.
Wing
There are both two wing halves drawn on the building plan. So you can assemble them simultaneously, if you want to. Lightly sand the CNC milled balsa ribs 1 (Det. G–G) to remove any imperfections.
Pin down the pre-shaped balsa leading edge 2 and the trailing edge 3 (please note – there is left and right one – match the notches to the plan). Glue the balsa ribs 1 in place. Glue the balsa root rib 4 between the leading and trailing edges – the bevelled side towards the root of the wing half (Det. F–F).
Glue the wing main spar 5 (3–8 mm spruce stick) into the notches in the upper side of ribs 1. Do not glue it to the root rib 4 yet. Glue the gussets 6 in place. Apply some additional glue to all joints if necessary and let cure. Now you can assemble the other half of the wing in the same way. Just remember you are building left and right halves, not two lefts or rights.
Once the glue has cured thoroughly cut the leading edge, trailing edge and main spar flush with the edge of the outer wing ribs. Sand the leading edge to the shape (Det. D–D). Glue the wing tip ribs 7 in place. Once cured, sand them to the shape. Trial fit the wing halves root ribs – if attached together the wing dihedral must be 150 mm (Det. E).
Glue the wing joiners 8 to both sides of the main spar 7 and into the notch in the root rib 4 of one wing half matching the upper edge of the main spar. Apply a generous amount of glue to both root ribs, wing joiners 8, leading and trailing edges, and attach the wing halves together. Lay one of the wing halves down on the building board. Secure it with a couple of magazines wrapped in a plastic bag serving as a weight. Align the other half so the tip of it was 150 mm above the building board (you can use a couple of books or a wooden block) and the trailing and leading edges were in one straight line. Let the glue cure thoroughly. Once cured, carefully sand the joint and the entire wing using sanding blocks with a coarse and then fine sandpaper to smooth any rough areas. The wing is ready to covering now.
Horizontal tailplane
The horizontal tailplane is to be built directly on the plan protected with a clear plastic film in similar manner as the wing. Pin down the spruce trailing edge 11 overlapping on both two ends. Glue the balsa centre plate 12 to the trailing edge 11. Glue the spruce leading edge 13 to the centre plate and pin it down, overlapping on both two ends. Glue in place the ribs 14 made. Start with the outer ribs first. Then proceed towards the centre of the horizontal tailplane.
Once the glue has cured thoroughly, remove the horizontal tailplane from the building plan. Sand the leading and trailing edges flush with the end ribs. Glue the tailplane tips 15 in place. With a sanding block, shape the tips and the leading and trailing edges (Det. A–A). The horizontal tailplane has been finished for now. Once covered with the tissue, glue the bamboo dowel (ø2.5×40 mm) 16 onto the centre plate 12 extending behind the trailing edge by 15 mm.
Fuselage and fin
The fuselage consists of the tail boom made of spruce sticks and balsa blocks and the front fuselage block made of Ceiba Plywood offering enough space for the ballast and timer (if you decided to install one). If you consider installing a timer (either mechanic or electronic) and dethermalizer, now it is the time to cut the openings in the fuselage block 25 as needed.
Start with the wing seat. Glue two balsa sticks 21 along the outer edges of the Plywood seat plate 20. Now glue the wing seat to the fuselage 25. Keep it centred and square to the side of the fuselage.
Glue spacers 22 to both sides of the fuselage along the bottom of the wing seat. Front edges matching the front edge of the wing seat plate. Glue the tail boom spruce sticks 23 (3×8×450 mm) to the fuselage sides. Fitting tightly into the notch in the spacers 22 and touching the rear edge of the wing seat plate. Glue the balsa spacer 24 (3×8×75 mm) between the rear ends of the tail boom sticks. Apply glue to both sides of the spacer. Insert it between the sticks 23 and clamp together using a clamp or clothes pegs. Immediately, before the glue set, lay the fuselage upside down onto the top view on the building plan placed on your work bench. Double-check the tail boom and the entire fuselage was true and straight. The tail boom sticks 23 and the spacer 24 aligned nicely.
Round the leading and trailing edges of the rudder 30. Use the tip of a pointy modeller's knife to cut slots for the brass tin rudder hinges 29 into the fin 28 and rudder 30. Cyano the hinges into the rudder and then into the fin leaving a slight gap between the fin and rudder. Glue the complete fin and rudder assembly between the tail boom sticks. The bottom edges matching. Glue the beech wing hold-down dowel 35 into the fuselage. Drill the hole for the horizontal tailplane hold-down dowel 34 (bamboo ø2.5×25 mm) using 2.5 mm drill bit (10 mm deep) and glue it in place. Make the front horizontal tailplane seat. Glue the spruce stick (3x5×25 mm) 27 to the Plywood plate (1 mm - 25×15 mm) 26. Glue it to the tail boom and into the notch in the fin. Lay the horizontal tailplane down on the seat in order to check the tailplane was square to the fuselage sides (when looking from the nose to the tail) and also square to the longitudinal axis of the fuselage (when looking from above). Cut 1.5 mm notches for the rubber band in the spruce stick 27 (refer to Det. J–J) using fine file, jigsaw or razor saw.
Glue the rear tailplane seat (balsa 3 mm – 9×12 mm) 39 to the fuselage. Bevel it slightly to match the horizontal tailplane bottom side. Insert and glue the main ballast 32 into the nose opening. Glue the side covers 33 in place matching the outline of the fuselage. Glue the cross-brace 38 (balsa 6×8×20 mm) between the tail boom sticks 23. Glue the skid 40 in place.
Doping and tissue covering
Lightly sand the entire airframe with the fine sand paper. Before the frames are covered, all EXTERNAL surfaces MUST be primed with the adhesive dope (diluted at least 1:1 with the thinner; the dope must have the viscosity of water - never use the dope unthinned!). Use a soft flat brush to apply the dope and, when dry, lightly sand all doped surfaces with the fine sandpaper. Apply the second coat, sand lightly again.
Sheets of the Vlies covering tissue are supplied in the kit. You can glue it to the airframe using water thinned white glue or adhesive dope. Always align the "grain" of the tissue the long way - from tip to tip of the wing or horizontal tailplane. The tissue sheets supplied in the kit have been already pre-cut to the correct size.
Horizontal tailplane: If you are new to the dope and tissue business, you should start with the horizontal tailplane in order to gain the skills on smaller part of your model featuring no curves. Apply the thinned white glue or adhesive dope around the external edges of the lower side of the tailplane and to the ribs and centre plate. IMMEDIATELY set the tissue in position and smooth the edges with finger tips before it has a chance to dry. Cut the tissue all around the outline of the tailplane leaving it 4–5 mm over size. Bend and glue with thinned white glue or adhesive dope the overlapping tissue around the entire tailplane. Cover the upper side of the tailplane in the same manner. Bend and glue with thinned white glue or adhesive dope the overlapping tissue around the entire tailplane.
Wing: Prepare four pieces of the tissue (do not forget the upper sheets are wider due to the airfoil camber). Again, start with the bottom side of one wing half – apply the glue/dope to the leading and trailing edges and all ribs, attach the tissue and smooth the edges with finger tips. Then proceed to the bottom of the other wing half. Cut the tissue all around the outline of the wing leaving it 4–5 mm over size. Bend and glue with thinned white glue or adhesive dope the overlapping tissue around edges of the entire wing.
Cover the upper side of the wing in the same manner – apply thinned white glue/adhesive dope to the trailing and leading edges, main spar and ribs. You will have to cut the tissue in short 4–8 mm portions around the wing tip in order to follow the curve of the tip.
There is no need to cover the fuselage. Now you can apply several coats of thinned shrinking dope in order to shrink the tissue and protect it from moisture. Once the tissue is nice and smooth without wrinkles (after 1–2 coats) you can apply the colour tissue trim – and continue in applying the shrinking dope.
Only apply the dope in a dry and well ventilated area at room temperature (over 20°C; low temperature/high humidity may cause "fogging" of some dopes turning them milky white instead of clear. If that happens you can usually cure it by taking the model to a dry and warm place and applying just the fresh thinner with a brush to the "fogged" part). Apply 3 to 5 coats of thinned dope to the entire model (use the top gloss dope for the fuselage and the last coat for the wing and horizontal tailplane). Lightly sand all doped surfaces with fine sandpaper between each coat. Apply the colour tissue trim to the fuselage before the last coat of dope (use the top gloss dope for the final coat). The stickers are to be applied only after the final coat!
Let the model dry thoroughly after each coat (2–3 days). Check for any warping of the wing or horizontal tailplane. If that happens, you have to lay the wing and/or tailplane down to a flat surface protected with a plastic film and weigh it down (a couple of magazines in a plastic bag to the rescue again) after each coat. Let it dry thoroughly.
Final assembly, Centre of Gravity (CG)
Secure the side towhook 36 to the left side of the fuselage using two screws 37 – refer to the building plan. The towhook is adjustable – you can move it forward on a windy day or backward on a calm day in order to achieve nice and steady climbing during the hi-start. Tie the wing and horizontal tailplane to the dowels on the fuselage using several loops of the supplied rubber thread.
Mark the position of the centre of gravity (refer to the building plan, marked with a dart) to the bottom of the wing seat on both sides of the fuselage using a permanent marker or a thin strip of colour sticky tape. Support the wing of the model with your fingertips in the centre of gravity position. The fuselage should be level. If the nose pitches up put in as much of additional ballast (not supplied in the kit) to the nose as necessary (you can use small screws, modelling clay etc.). The correct balancing is essential; incorrectly balanced model will be difficult to set up or unable to fly at all!
Flying
Once again check the correct position of the centre of gravity, check for any excessive warping of the wing, tailplane and fuselage. Choose a nice calm day for the first flight.
The model must be launched into the wind every time. Throw grass into the air to observe the wind direction. Hold your model with the wing and fuselage level. Launch your model with a gentle push straight with the nose pointing slightly down. Do not throw your model with nose up, or at greater angle than 10 degrees down. The model must have a certain minimum speed from the very start to stay airborne. It is not enough to just place your model in the air. It is better to land in tall grass in order to prevent any damage to your model during initial trimming.
If everything is OK (correct wing and tailplane alignment, correct CG position) DINGO will fly with the wings level in a nice glide with her nose pointing slightly down. If the model glides straight down to the earth a few paces in front of you, check the CG position again. If OK, add a thin piece of balsa or plywood under the trailing edge of the horizontal tailplane until the model glides in a nice flat and straight path. On the other hand, if your model pitches the nose up and stalls, sand the rear horizontal tailplane seat 39 step by step, until the model glides in a nice flat and straight path.
Once satisfied, bend the rudder 30 slightly (about 2 mm) to the left (looking from the tail to the nose). Now the model should glide in large left (counter clockwise) turns. Whilst under tow, the off-centre towhook would force your DINGO right - resulting in straight flight. Elementary!
Once trimmed out you can try your first hi-start with your DINGO using 25 m towline (a fishing line). You can purchase a towline set in your local model hobby shop or you can make your own from scratch. Get a towline (any fishing line strong enough to hold 5 kg fish is OK), tie a key ring to one end (bowline knot is the best) and a flag (a piece of red cloth) 20–30 cm from the end. The flag makes the towline visible in the air as well as on the ground. Find a suitable spool to keep the towline on.
Hook the ring at the towhook and ask a friend to hold (and launch later) your model. Unwind the towline walking into the wind keeping is slightly stretched. The launch position of the model: wings level, nose very slightly up, directly into the wind.
Give a signal to your friend holding your model. Both of you will start running into the wind, the assistant will launch the model after a few paces. Continue running into the wind paying attention to the tension of the towline and checking the model over your shoulder. Run as fast as necessary to achieve steady climbing rate of your model. The model should climb straight forward, at steady rate, in a nice arc. The stronger the wind, the slower you might run. If the towline tension decreases, your model climbs slowly (and yaws to a side) you should run faster. If the towline tension increases and the model violently turns to a side, you have to slow down and wait until the model returns to the original straight path. Hi-start requires some skills. Especially on a windy day running too fast might even end in destruction of your model. Once the mode climbs almost over your head, it should start turning slightly left – this is the moment to stop. Let the model fly in front of you and release the towline.
For the initial high start, set the towhook to the forward position. Based on the DINGO's behaviour you can move it back/adjust later. If your model hesitates to climb, move it back. If pitches the nose up and veers to side, move it forward. Adjust the rudder to achieve large flat left turns. Tight banked turns kill the altitude! Usually, just 2 mm left offset is OK. Contest flyers would want to install the dethermalizer with a timer that kicks the horizontal tailplane up (about 45°) once the set time has elapsed, the model will land in large "hoops" then.
The kit contents
| Part | Building plan no. | Quantity |
|---|---|---|
| Fuselage block – 8 mm ceiba Plywood | (25) | 1 |
| Building plan | 1 | |
| Instruction manual | 1 | |
| Vlies tissue sheet | 3 | |
| Sand paper fine & coarse | 1+1 | |
| Stick bundle | ||
| Fuselage stick - spruce 3×8×450 mm | (23) | 2 |
| Wing leading edge - balsa 7×7×410 mm | (2) | 2 |
| Wing trailing edge - balsa 14×4.5×410 mm | (3) | 2 |
| Wing main spar - spruce 3×8×410 mm | (5) | 2 |
| Spruce stick 3×5×410 mm | (11, 13) | 2 |
| Small parts bag A | ||
| Fuselage side cover | (33) | 2 |
| Side spacer | (22) | 2 |
| Balsa spacer 3×8×75 mm | (24) | 1 |
| Balsa rudder | (30) | 1 |
| Beech dowel ø3×30 mm | (35) | 1 |
| Bamboo dowel ø2.5×22 mm | (34) | 1 |
| Rear horizontal tailplane seat - Balsa ø3×9×12 mm | (39) | 1 |
| Horizontal tailplane seat - Plywood 1 mm - 25×15 mm | (26) | 1 |
| Spruce stick 3×5×25 mm | (27) | 1 |
| Tail boom cross-brace – Balsa 6×8×20 mm | (38) | 1 |
| Skid | (40) | 1 |
| Towhook | (36) | 1 |
| Wood screw | (37) | 2 |
| Rudder hinge (brass tin) | (29) | 2 |
| Ballast ø20×8 mm | (32) | 1 |
| Small parts bag B | ||
| Fin | (28) | 1 |
| Wing seat plate | (20) | 1 |
| Balsa stick 3×5×120 mm | (21) | 2 |
| Wing root rib (bevelled) | (4) | 1+1 |
| Wing tip | (7) | 2 |
| Wing joiner "V" | (8) | 2 |
| Gusset | (6) | 8 |
| Small parts bag C | ||
| Wing rib | (1) | 20 |
| Small parts bag D | ||
| Balsa stick 3×5×59 mm | (14) | 8 |
| Balsa stick 3×5×69 mm | (15) | 2 |
| Balsa centre plate 3×20×59 mm | (12) | 1 |
| Bamboo dowel ø2.5×40 mm | (16) | 1 |