KAVAN Cumul DLG ARF 1096mm – Instruction manual

KAV02.8023.ARF

KAVAN Cumul DLG ARF

Introduction

The KAVAN Cumul DLG ARF is a partly assembled RC discus-launch glider. The wing panels, fuselage and tail surfaces are supplied built and covered. Complete the wing joint, tail installation, radio installation and pre-flight checks as described below. This is the ARF version, SKU KAV02.8023.ARF.

Before you start

1. If you are new to model aircraft, ask an experienced modeller to check your completed model and help you with the first flights. Your model shop or local model flying club can help you find an instructor.
2. Build the model according to these instructions. Do not alter or modify it, as this can make it unsafe or unable to fly. Take time to build everything straight, true and strong.
3. Check the kit for missing or damaged parts before starting. Familiarise yourself with each component and contact your dealer immediately if a replacement is needed.
4. Trial fit every part before gluing. Check that you have the correct part and that it fits properly; extra glue cannot compensate for a poor fit.
5. Set the centre of gravity (CG) and control throws as described in Pre-flight preparation before the first flight. Incorrect balance can make the model unstable or unable to fly.

Note

Check the contents and report missing or damaged parts before starting construction.

Safety precautions

Danger

This model is not a toy. Even though it is light and slow in flight, incorrect handling can cause injury or damage. Build, test and fly it responsibly, following the instructions, applicable model flying safety rules and common sense.

Use suitable tools and accessories in good condition. Install all parts correctly and check the model before the first and every subsequent flight. Do not fly a damaged model. Beginners should fly with help from an experienced modeller.

Children under the age of 14 must operate the model under adult supervision. Fly in calm weather or a light breeze at a safe site away from obstacles.

Technical specifications

Parameter	Value
Wingspan	1096 mm
Length	880 mm
All-up weight	From 180 g
Wing section	YA 0801
CG position	69–72 mm
Controls	Rudder, elevator

Recommended RC equipment

• At least a two-channel transmitter and a miniature receiver suitable for a 1S LiPo supply.
• Use two approximately 6g servos with a torque of 0.7–0.9 kg·cm; check that both servos and receiver support the battery voltage.
• Rudder and elevator servo: KAVAN GO-6MG 2×
• Receiver battery: 1S LiPo 3.7 V 450–500 mAh

Recommended glues

Unless stated otherwise, use medium cyanoacrylate (CA) glue (KAV56.9952 KAVAN Power CA Medium). The highly loaded parts (wing joiner etc.) should be glued together using 30-minute (or slower) epoxy (KAV56.9965 / KAV56.9966 / KAV56.9967) offering high strength and enough time for the correct positioning.

Tools and accessories

• Very sharp modeller’s knife (KAV66.770) with no. 11 blades
• Scissors
• Electric drill with drill bits
• Wire cutter
• Long nose pliers
• Screwdrivers
• Razor saw
• Sandpaper no. 180–220 and 360–400
• Needle files
• Soldering iron and solder
• Modeller’s pins (KAV66.0355)
• Epoxy mixing stick and vessel
• Masking tape, clear sticky tape
• Rubbing alcohol (for cleaning up excessive epoxy)
• Paper tissue or soft cloth (for cleaning up excessive epoxy)
• Straightedge with scale
• Square edge
• Thin clear plastic film (for protecting the building plan/workbench)
• Permanent marker
• Hot melt glue gun & hot melt glue

Main section

Model assembly

Wing

1. Locate the W1 and W2 riblets, W34 wing joiner and W32 wing bolt plate. (Fig. 2)
2. Sand lightly the edges of all the parts. Trial fit the wing joiner W34 – it has to go all the way into the respective bays in wing halves easily – sand the joiner slightly or trim the bays using a fine needle file if necessary.
3. Using a very sharp pointed modeller’s knife remove the covering film over the notch for the W32 wing bolt plate near the trailing edge of the wing halves. Slide the wing panels onto the W34 wing joiner. Insert the W1 and W2 riblets between the root ribs and the W32 plate into the notches in the wing panels and W2 riblet. Secure the wing panels using strips of masking tape. Attach the wing to the fuselage to check the alignment pin of the W1 riblet engages correctly into the corresponding slot in the fuselage and the hole in the W32 plate matches the position of the captive nut pre-installed in the fuselage. (Fig. 3)
4. Once you are satisfied, use 30 min epoxy to glue the W34 wing joiner in place as well the W1 and W2 riblets aligned to match the wing root rib. (Fig. 4)
5. Put the wing half with the wing joiner glued in on your workbench (protected by a sheet of plastic film) so the alignment pin of the W1 riblet protrudes over the edge of the table; then use 30-minute epoxy to attach the other wing panel. Be sure the trailing edges of both wing panels match perfectly. (Fig. 5)
6. Use 30-minute epoxy for W32 as well. Drill through W2 after curing, using Ø3.2 mm (approximately 1/8″) as specified in the source; check fit of the supplied M4 bolt without forcing it. Finally, cover the wing centre joint with clear adhesive tape. (Fig. 6)
7. Epoxy thoroughly the carbon discus launch pin into the left (for a right-handed pilot) or right (for a left-handed pilot) wing tip. (Fig. 7)

Fuselage

1. Using a very sharp pointed modeller’s knife, cut the covering film over the opening for the tailplane pylon in the horizontal stabilizer and over control horn slots in the elevator and rudder. Cut the small slots for the Kevlar® thread in the fin. (Fig. 9)
2. Use a fine needle file to trim the pre-cut slots for the horizontal tailplane pylon, fin and elevator and rudder push rod exits in the carbon tube tail boom. Use a round fine needle file to make a groove for the rudder push rod tube in the tailplane pylon F22. (Fig. 8)
3. Insert the tailplane pylon F22 into the tail boom – no glue yet. Insert the fin and rudder assembly into the notch at the end of the tail boom and tack glue it to the tail boom. Bind the fin to the tail boom with a Kevlar® thread threaded through the slots in the fin. (Fig. 9)
4. Slide the horizontal stabilizer on the F22 tailplane pylon; align it square to the fin and to the longitudinal axis of the tail boom and tack glue it to the pylon. Double-check the correct alignment; once satisfied, apply medium cyano along all the joints and onto the Kevlar® thread. Insert the elevator and rudder push rod outer tubes into the tail boom. Secure them with a piece of polyurethane foam soaked with epoxy that you will work into the centre of the tail boom with a thin stick. This is great for a precise, slop-free elevator and rudder control. (Fig. 10)+(Fig. 11)
5. The servo mount supplied in the kit has been tailored for the recommended KAVAN GO-6MG servos. Whatever type of servos you are going to use, always check if the openings won’t need a bit of trimming first. We recommend soaking the edges of the servo openings with cyano. Once satisfied, glue the servo mount in place (the servos are to be fitted in the upside-down position). (Fig. 12)+(Fig. 13)
6. Thread the protruding ends of the elevator and rudder push rod outer tubes through the holes in the rear servo compartment former so the tubes lead directly to the horns of servos in the servo mount. Insert the tail boom into the fuselage – no glue yet. (Fig. 14)
7. Attach the wing to the fuselage and secure it with the M4 bolt. Looking from above, front and rear check the fuselage and tail boom are straight and the wing dihedral makes a nice symmetrical „V“ in relation to the horizontal stabilizer. Once satisfied cut the push rod outer tubes to the correct length and epoxy thoroughly the tail boom into the fuselage. Double-check the correct alignment before the glue sets.
8. Solder the M2 brass threaded couplers onto one end of the Ø0.8 mm piano-wire pushrods. Screw on the ball links, slide the pushrods into their outer tubes and attach the ball links to the servo arms with the supplied M1.6 screws. Dry-fit the fibreglass control horns in the elevator and rudder. With the radio switched on, centre the servos and fit their arms square to the servo cases. Align the elevator and rudder with the stabilizer and fin. Mark the pushrod lengths and form right-angle L-bends at the control-surface ends; Z-bends may also be used. Insert the bends into the control horns and cyano the horns into the moving control surfaces, keeping them neutral. Secure the servos in the tray with small amounts of hot-melt, silicone or MS polymer adhesive. (Fig. 15)+(Fig. 10)+(Fig. 11)
9. Glue the F14 locking plate to the front of the servo & battery compartment hatch; the locking plate has to match the position of a notch in the fuselage side reinforcement plate; the hatch has to match the opening in the fuselage side. Epoxy the pair of magnets F15 into the hatch and fuselage. Double-check their polarity – they have to cling to each other! For easy removal, apply a strip of folded sticky tape to the rear edge of the hatch. (Fig. 16)+(Fig. 17)
10. Install your receiver into the fuselage under the wing; the receiver battery will go into the nose.

Tow hook

1. Install the tow hook in the plywood tow hook plate – drill through one of the pre-drilled holes using a 3.0mm drill bit. It should be positioned about 5 mm in front of the centre of gravity. (Fig. 18)

Centre of gravity and control throws

Setting	Value
CG position	69–72 mm
Rudder	±25 mm
Elevator	±10 mm
Discus launch configuration	Rudder offset 1 mm opposite the direction of rotation (right-handed pilot: 1 mm right), elevator 1 mm down.

Note

Use this configuration for the climbing phase of the discus launch only; and only after the model has been trimmed out properly and you’ve made yourself familiar with the controls.

Flying

Be sure you are using fully charged batteries. Now (and before any further flight again) check the correct function of the whole radio equipment and movement of the control surfaces. Be sure any part of flight equipment cannot move during flight. We strongly recommend making a range check (see your radio instruction manual for details).

The first flight

Choose calm weather or a light breeze below 3 m/s. Fly only on a safe site such as an RC club flying field. Glider will be very happy on your favourite slope on a calm day. The very light lift will allow perfect fine trimming out.

Switch your transmitter and then the receiver on and check all the working systems one more time. Facing INTO the wind hold your transmitter in one hand; grip the model in the other hand near the centre of gravity. Hold it at head level and give the model a fairly powerful push exactly into the wind; wings level, nose slightly down. An experienced helper can launch the model for you. Your model should now glide in a long, flat and straight path without needing any help from you. Use the controls gently if necessary, and adjust the trim tabs until your Cumul DLG glides above the described way. Now check the position of control surfaces; set the length of pushrods to bring back trim tabs on your transmitter to a central position if necessary (do this even if your transmitter stores trim settings). Check again the gliding of your Cumul DLG.

Now you are ready to make your first discus launch.

Discus launch

The discus launch allows your model to reach quite a high altitude without much effort. As it is with any „sports performance“, it will require some training to do it right – our step-by-step manual makes it easy. We will describe the procedure for a right-handed pilot; with the launching pin attached to the left wingtip. The left-handed procedure is the mirror image. Practise the complete rotation slowly without releasing the model before attempting an actual launch.

Position A – getting ready

Your right index finger and middle finger should be wrapped around the launch pin at the left wing tip. Your thumb is to be gently pressed against the leading edge of the wing. Hold the transmitter in your extended left hand. Stand with your left shoulder into the wind and the right wing tip pointing at ca 45° angle to the ground.

Position B – the first step

Take a long step with your left foot pulling the Cumul DLG up and forward with your right arm.

Position C – rotation

Step into an anticlockwise turn with your right foot, keeping the Cumul DLG flat and your right arm extended.

Position D – continued rotation

The second half of the rotation – the part that is most important for a good launch. Do not use too much arm in this section. Just let the swing of your torso speed the Cumul DLG up.

Position E – release

By this time in the launch the plane will be trying to climb on its own. Just release your fingers and let the plane fly out of your hand directly into the wind.

Position F – taking control

Regain your balance and immediately hold the transmitter with both hands while watching the model. Be ready to apply down-elevator if it climbs too steeply, or up-elevator if a poor release sends it towards the ground.

The plane will climb after release – the climb angle should be shallow at first. Once you are well acquainted with the discus launch you can use more force and increase the launch angle up to 60–80°. When completely familiar and comfortable you can add two quick steps before starting the turning sequence to get some extra speed and energy.

When the plane has slowed almost to the point of stopping promptly apply down-elevator to achieve level flight. When this is done at the right moment the plane will go into horizontal flight with just enough airspeed to maintain a gentle glide. If it is done too early the plane will pitch its nose up dangerously after a short dive. If it is done too late the plane will stall.

Congratulations, you’ve made it!

Appendix

Assembly illustrations

Note

Please note the pictures are just for illustration only – some show our prototype that might differ slightly from the actual, regular series production kits.

Parts list

Main parts

Part	Quantity	Building plan no.	Material
Instruction manual	1
Sheet of stickers	1
Pushrod set	2		Plastic tube + 0.8 mm piano wire
Tail boom	1		carbon tube Ø6/5 mm
Built fuselage with hatch	1
Left wing panel	1
Right wing panel	1
Horizontal tailplane	1
Fin and rudder	1

Bag no. 1 – small parts

Part	Quantity	Building plan no.	Material
Tow hook	1		metal
Neodymium magnet Ø3 mm	2	F15
Wing Bolt M4	1		M4 nylon
Control horn	2		fibreglass 1.5 mm
Ball Link Short M2	2
Threaded Coupler M2	2		brass M2/0.8 mm
Rudder and Elevator Servo Tray	1	F12	balsa 4 mm
Carbon Pin	1		Ø5 mm
Fuselage Hatch Lock	1	F14	liteply 3 mm
Wing Riblet	1	W2	liteply 3 mm
Wing Riblet	1	W1	plywood 3 mm
Wing Joiner	1	W34	plywood 3 mm
Wing Bolt Plate	1	W32	plywood 2 mm
Tailplane Pylon	1	F22	liteply 3 mm
Kevlar thread	1