KAVAN DARA A1 (F1H) 1200mm - Instruction manual
Introduction
The F1H glider DARA 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 (KAV56.9952 KAVAN Medium CA etc.).
Dope: KAVAN STANDARD line Adhesive dope (KAV56.9988), Shrinking dope (KAV56.9986) or coulor Shrinking dope (KAV56.9987x) and Thinner (KAV56.9992) 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 with 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 | 1200 mm |
| Length | 815 mm |
| All-up weight | 225 g (min 220 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. Pin the tapered balsa trailing edge 3 to the building plan and mark the position of the notches for ribs with a soft pencil. Remove the trailing edge and use a fine flat file to cut the notches according to the building plan. 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 now featuring all those beautiful notches. Glue the balsa ribs 1 in place. Fit, cut to size and glue the bottom balsa sheeting 4 between the leading and trailing edge. Glue the balsa root rib 5 along the edge of the sheeting – the bevelled side towards the root of the wing half (Det. F–F). Glue the rib 6 about 2 mm inset along the outer edge of the central sheeting. Glue the wing main spar 7 (3×8 mm spruce stick) into the notches in the upper side of ribs. Fit and glue the upper central sheeting 8 and 9 (Det. B–B) in place. Glue the gussets 42 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 upper central sheeting flush with the bevelled root ribs 5. Sand the leading edge to the shape (Det. D–D). Glue the wing tip ribs 41 in place. Once cured, sand them to the shape.
Trial fit the wing halves root ribs. If attached together the wing dihedral must be 200 mm (Det. E). Once satisfied, apply a generous amount of glue to both root ribs (including upper and bottom sheeting 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 200 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. Wrap 25 mm strip of nylon fabric all over the joint on both sides of the wing and apply thinned adhesive dope to it thoroughly. Once the dope has cured, sand the entire wing frame with fine sandpaper. 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 (3×5×405 mm) 11 overlapping on both two ends. Glue the balsa centre plate (3 mm – 30×80 mm) 13 to the trailing edge 11. Glue the spruce leading edge (3×5×385 mm) 10 to the centre plate and pin it down overlapping on both two ends. Cut to size and glue in place the diagonal ribs 12 made of 3×5 mm balsa stick. Start with the outer diagonal ribs first; then proceed towards the centre of the horizontal tailplane.
Glue the spruce main spar 14 (3×5×200 mm) to the top of the horizontal tailplane framework. Fit and glue the front balsa upper plate 16 (3 mm – 30×30 mm) and two rear plates (3 mm – 13.5×45 mm) 17. Align the outer edges of the plates 17 to match the bottom plate 13 leaving about 2.5 mm slot between them to fit the bamboo dowel 18 later. Sand the gussets 15 to fit and glue them in place.
Once the glue has cured thoroughly, remove the horizontal tailplane from the building plan. With a sanding block, shape the tips and centre plates as indicated on the plans (Det. A–A). Round the leading and trailing edges and the tips (Det. A–A). The horizontal tailplane has been finished for now. Once covered with the tissue, glue the bamboo dowel (ø2.5×50 mm) 18 between the plates 17 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 with poplar Plywood side covers offering enough space for the ballast and timer (if you decided to install one).
Start with the tail boom. Glue it on the building board in order to make the tail boom true and straight. Glue the front balsa block 20 to the spruce stick (2×8×600 mm) 22 taking care the outer edges of the block matched the edges of the stick.
Now apply glue to the rear part of the spruce stick 22 and block 20. Attach the rear balsa block 21 matching the edges of the stick. Glue the other 2×8 mm spruce stick 23 to the tail boom.
If you consider installing a timer (either mechanic or electronic) and dethermalizer, now it is the time to trim the openings in the fuselage block 24 as needed. Do not forget to cut an appropriate opening in one of the side covers (26 or 28) as well.
Insert the tail boom in the notch in the fuselage block 24. Trim the notch if necessary. Remove the tail boom, apply a generous coat of glue into the notch and insert the tail boom. Glue it on the building board in order to make the fuselage true and straight. Insert the two beech dowels 25 (ø4×32 mm) into the fuselage – no glue yet. The dowels will help with the correct alignment of the side covers. Apply glue to the left side of the fuselage block. Align and attach the side cover 26. You can lay the fuselage down onto your building board and weigh the cover down to cure. Insert and glue the main ballast 27 into the nose opening. Glue the other side cover 28 in place.
Glue the reinforcement plate 30 into the fin 29. Make the front horizontal tailplane seat. Glue the spruce stick (3×5×25 mm) 32 to the Plywood plate (1 mm - 25×15 mm) 31.
Mark the position of the tailplane seat to the fuselage according to the building plan and glue it to the tail boom. 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). Glue the rear tailplane seat (balsa 1.5 mm – 8×10 mm) 33 to the fuselage. Glue the fin 29 to the fuselage. Use the horizontal tailplane as a reference again. The fin has to be square to the horizontal tailplane and exactly in the longitudinal axis of the fuselage. Round the leading and trailing edges of the rudder 41. The brass rudder hinges 45 will be installed after doping and covering of the model.
Next is the wing seat. Glue two spruce sticks (3×5×120 mm) 37 along the outer edges of the Plywood seat plate (1.5 mm – 32×120 mm) 36. Once the glue has cured, attach the wing seat to the fuselage positioning it according to the building plan and mark the position of the holes for wing seat fixing screws. Drill the holes with a 1.5 mm drill a bit about 10 mm deep. Apply glue to the top of the fuselage, attach the wing seat and secure it with two screws 40. Glue the beech wing hold-down dowels 25 into the fuselage.
Mark the position of the holes for the horizontal tailplane hold-down dowels 34 and 35 (bamboo ø2.5×25 mm) and glue them 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 clear dope. Always align the "grain" of the tissue the long way - from tip to tip of the wing or horizontal tailplane.
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. Cut a piece of the tissue 10 mm oversized all around the outline of the horizontal tailplane. Apply the thinned white glue or adhesive dope around the external edges of the lower side of the tailplane and to the diagonal 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 clear dope the overlapping tissue around the entire tailplane.
Cover the upper side of the tailplane in the same manner – apply thinned white glue/adhesive dope to the trailing and leading edges, main spar, centre plates and tips. Do not apply the glue to the diagonal ribs!
Wing: Cut four pieces of the tissue 10 mm oversized all around the outline (do not forget the upper sheets have to be wider due to the airfoil camber). Again, start with the bottom side of one wing half. Apply the glue/ adhesive 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.
You can cover the tail boom as well (apply 4 slightly overlapping strips to the bottom both sides and finally to the top of the boom) to add some extra strength. There is no need to cover the nose.
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 top gloss 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 39 to the left side of the fuselage using two screws 38 – 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. Use the tip of a pointy modeller's knife to cut slots for the brass tin rudder hinges 45 into the fin 29 and rudder 45. Cyano the hinges into the rudder and then into the fin leaving a slight gap between the fin and rudder. Tie the wing and horizontal tailplane to the dowels on the fuselage using several loops of the supplied rubber thread.
Drill 5 mm access hole into the additional ballast compartment in the fuselage (refer to the building plan). Support the wing of the model with your fingertips in the centre of gravity position (the point marked by an arrow on the fuselage plan). The fuselage should be level - if the nose pitches up put in as much of additional ballast (not supplied in the kit) as necessary (you can use pellets, small screws etc.) Once satisfied, cover the hole with a strip of clear sticky tape.
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) DARA 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.
Once satisfied, bend the rudder 41 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 DARA right - resulting in straight flight.
Once trimmed out you can try your first hi-start with your DARA using 25–50 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 mode. 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 DARA'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 | (24) | 1 |
| Side cover – 3 mm poplar Plywood | (26, 28) | 2 |
| Wing centre sheeting - balsa 1.5 mm – 100×40 mm | (4, 8, 9) | 6 |
| Stick set A | ||
| Fuselage stick - spruce 2×8×600 mm | (22, 23) | 2 |
| Wing leading edge - balsa 7×7×600 mm | (2) | 2 |
| Wing trailing edge - balsa 14×4.5×610 mm | (3) | 2 |
| Wing main spar - spruce 3×8×610 mm | (7) | 2 |
| Stick set B | ||
| Spruce stick 3×5×405 mm | (11) | 1 |
| Spruce stick 3×5×385 mm | (10) | 1 |
| Spruce stick 3×5×195 mm | (14) | 2 |
| Balsa fuselage block – thick | (20) | 1 |
| Balsa fuselage block – thin | (21) | 1 |
| Balsa stick 3×5×300 mm | (12) | 6 |
| Vlies tissue sheet | 3 | |
| Red tissue trim sheet | 1 | |
| Blue tissue trim sheet | 1 | |
| Sand paper fine & coarse | 1+1 | |
| Building plan | 1 | |
| Instruction manual | 1 | |
| Small parts bag A | ||
| Fin | (29) | 1 |
| Fin reinforcement plate | (30) | 1 |
| Rudder | (41) | 1 |
| Vertical tailplane seat - Plywood 1 mm - 25×15 mm | (31) | 1 |
| Spruce stick - 3×5×25 mm | (32) | 1 |
| Rear vertical tailplane seat – balsa 1.5 mm – 8×10 mm | (33) | 1 |
| Wing seat plate – Plywood 1.5 mm - 32×120 mm | (36) | 1 |
| Spruce stick - 3×5×120 mm | (37) | 2 |
| Gusset | (15, 42) | 10 |
| Balsa plate – balsa 3 mm 30×80 mm | (13) | 1 |
| Balsa plate – balsa 3 mm 30×30 mm | (16) | 1 |
| Balsa plate – balsa 3 mm 13.5×45 mm | (17) | 2 |
| Small parts bag B | ||
| Towhook | (39) | 1 |
| Nylon fabric | 1 | |
| Screw ø2×8 mm | (38, 40) | 4 |
| Rubber thread ø1×600 mm | 3 | |
| Bamboo dowel ø2.5×25 mm | (34, 35) | 2 |
| Bamboo dowel ø2.5×50 mm | (18) | 1 |
| Beech dowel ø4×32 mm | (25) | 2 |
| Ballast ø26×8 mm | (27) | 1 |
| Rudder hinge (brass tin) | (45) | 2 |
| Small parts bag C | ||
| Main wing rib | (1) | 28 |
| Wing root rib (bevelled) | (5) | 2 |
| Support rib | (6) | 2 |
| Wing tip | (41) | 2 |