Model Tech Yak 54 Assembly Instructions Manual

Optimized for precision 3d aerobatics

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Optimized for Precision 3D aerobatics, the Model Tech Yak 54 ARF has enlarged and modified control surfaces to enhance control

response at low-airspeed and high-alpha. Wrung out by Model Tech test pilots in months of testing, the Yak 54 ARF has already proven

to be a stunning performer. You'll find this Yak 54 ARF is perfectly 3D capable when matched with a YS 110 or Magnum 120 four-stroke

and is insanely overpowered with an engine such as the Mark/Moki 1.35 two-stroke. And regardless of the engine chosen, you can find

proper balance more easily due to the multiple choices for servo positions and linkages. Exciting, yet well-behaved, this Yak 54 ARF

will have you in the air and pushing the envelope like never before.

Check out our website for more information on other exciting Model Tech products!

Model Tech Co., Ltd.

Hong Kong

Version November 2008

Wing span: 66.5 Inches (690mm)

Weight rTf: 8.5 to 0 Pounds (3.85 to 4.53kg)

functions: Ailerons, Elevator, Rudder, and Throttle

Made in China

ASSEMBLY INSTRUCTIONS

hTTP://ModElTECh.globalhobby.CoM

Precision-Built, CAD-Designed Airframe for Light Weight and High Strength

Laser-Cut, Balsa and Plywood Construction

Fiberglass Cowl and Wheel Pants

Aluminium Landing Gear Brackets

Two-Piece Plug-In Wing Panels with Aluminium Wing Joiner Tube

Pull-Pull Elevator (or Optional Push-Pull) and Pull-Pull Rudder Control Linkages

Removable Top Deck Canopy for Easy Radio Compartment Access

Accepts a Wide Range of Engine Sizes

sPECifiCaTioNs

Wing area: 875 Square Inches (56.45dm

fEaTurEs

)

Wing loading: ~23 Ounces/Square Foot (~68gr/dm

Engine required: .00 to .35 Two-Stroke or .20 to .40 Four-Stroke

Page

length: 65 Inches (650mm)

)

Kit Product Number MT3173E

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Summary of Contents for Model Tech Yak 54

Page 1 Wrung out by Model Tech test pilots in months of testing, the Yak 54 ARF has already proven to be a stunning performer. You'll find this Yak 54 ARF is perfectly 3D capable when matched with a YS 110 or Magnum 120 four-stroke and is insanely overpowered with an engine such as the Mark/Moki 1.35 two-stroke.
Page 2: Table Of Contents
Model Tech guarantees this kit to be free from defects in both material and workmanship at the date of purchase. This does not cover any component parts damaged by use, misuse or modification. in no case shall Model Tech's liability exceed the original cost of the purchased kit.
Page 3: Our Recommendations
Magnum 2-3/4" (70mm) Aluminium Spinner The Yak 54 ARF allows the option of mounting the two elevator servos in the back of the fuselage (if using a heavier engine), or under the cockpit deck (if using a lighter engine). If you mount the elevator servos under the cockpit deck, servo extensions should not be necessary.
Page 4: Tools And Supplies Required
Tools aNd suPPliEs rEQuirEd q 5 Minute and 30 Minute Epoxy q Straight Edge Ruler q Thin and Thick Cyanoacrylate (C/A) q Pencil q C/A Debonder q Builder's Triangle q Thread Locking Compound q 220 Grit Sandpaper q Formula 560 Canopy Glue q Sanding Block q Silicon Sealant q Rotary Tool with Cutting Disc and Sanding Drum...
Page 5: Kit Contents
Before you begin assembly, group the parts as we list them below. This will ensure that you have all of the parts before you begin assembly and it will also help you become familiar with each part. If you find any parts missing or damaged, please contact your local Model Tech dealer directly, using the separate Customer service sheet included with your kit.
Page 6 ElEvaTor CoNTrol sysTEM (Push-Pull oPTioN) q (2) 8-/2" (26mm) Threaded Pushrod Wires q (2) M3 x 40mm Machine Screws q (4) Metal Clevises - 3mm Thread q (4) M3 Hex Nuts ruddEr CoNTrol sysTEM q () Stranded Cable q () M3 x 70mm Threaded Rod q (2) Nylon Adjustable Control Horns q (2) Threaded Couplers q (2) Z-Bend Couplers...
Page 7: Replacement Parts
If you need to order replacement parts, we recommend ordering directly from your local hobby retailer. If your hobby retailer does not stock Model Tech products, you can order replacement parts directly from your local distributor, using the Customer Service Information Sheet included with your kit.
Page 8: Wing Assembly
WiNg assEMbly you'll NEEd ThE folloWiNg ParTs froM ThE KiT: q () Right Wing Panel with Aileron q (8) Pinned Hinges q () Left Wing Panel with Aileron you'll NEEd ThE folloWiNg Tools aNd suPPliEs: q 5 Minute Epoxy q Paper Towels q Modeling Knife q Rubbing Alcohol q Epoxy Mixing Sticks...
Page 9 q Mix a small quantity of 5 minute epoxy and carefully glue each of the four hinges into only the aileron for now. Make sure that each of the hinges is centred and that the centreline of each hinge pivot point is even with the leading edge of the aileron.
Page 10: Wing Mounting
q Remove the protective backing from the covering material. With the control surface fully deflected in the 'UP' position, place the length of covering material over the hinge line (on the bottom), making sure that the crease is pushed completely down into the hinge line. IMPORTANT Only the bottom of the hinge gap needs to be sealed.
Page 11: Stabiliser Installation
q Gently slide the wing joiner tube into the left wing panel until the wing joiner tube bottoms out. sTEP 3: iNsTalliNg ThE WiNg PaNEls aNd rETaiNiNg CliPs q Carefully slide the other end of the wing joiner tube through the fuselage and firmly push the wing panel up against the fuselage side.
Page 12 sTEP 1: aligNiNg ThE horizoNTal sTabilisEr q Remove the elevator halves from the stabiliser and set them aside for now. Discard the temporary hinges that are used for packing. q Cut away the covering material from over each side of the horizontal stabiliser mounting slot in the fuselage.
Page 13 q When you're satisfied that the stabiliser is square to the wing, use a T-Pin to hold the front of the stabiliser firmly in place and aligned. q Look from the front of the aircraft at both the wing and the stabiliser. When aligned properly, the stabiliser should be parallel to the wing.
Page 14 sTEP 3: aligNiNg aNd iNsTalliNg ThE vErTiCal sTabilisEr q Remove the rudder from the stabiliser and set it aside for now. Discard the temporary hinges that are used for packing. q Push the stabiliser down into the mounting slot, making sure that the rudder post is pushed firmly into the slot in the back of the fuselage.
Page 15: Tail Wheel Installation
sTEP 6: hiNgiNg ThE ruddEr q Hinge the rudder to the vertical stabiliser, using the same techniques that you used to hinge the elevator halves to the horizontal stabiliser. The rudder is hinged using three hinges and the bottom of the rudder should be even with the bottom of the fuselage.
Page 16: Main Landing Gear Installation
q Drill three 5/64" (2mm) diameter pilot holes through the fuselage, then install the tail wheel mounting bracket, using three M3 x 2mm wood screws. q Thread the M2 x 2mm wood screw through the hole in the bottom of the steering arm mounting bracket and into the rudder, to secure the steering arm into place.
Page 17 sTEP 1: iNsTalliNg ThE laNdiNg gEar braCKETs q Install the two main landing gear brackets onto the fuselage, using six M4 x 12mm socket-cap screws and six M4 flat washers. q Install one threaded axle onto each landing gear bracket, using two M8 lock nuts.
Page 18: Engine Installation
q Install one M3 blind nut into the wheel pant, then carefully apply a bead of thick C/A around the blind nut for extra security. PRO TIP Thread one M3 x 10mm machine screw and one flat washer into the blind nut, then tighten the machine screw to draw the blind nut into place.
Page 19: Fuel Tank Assembly And Installation
IMPORTANT The precut mounting slots in the firewall are elongated to allow you to mount engines of varying width. To ensure that the engine lines up with the centre of the cowl, it's important that the engine mounts be centred within the precut mounting slots. q Line up the engine mounting beams within the precut slots in the firewall and temporarily install the four M4 x 25mm socket-cap screws, four M4 split washers, four M4 flat washers and four M4 blind nuts.
Page 20 q Carefully bend the longer of the two aluminium tubes up at a shallow angle, being careful not to kink the tubing as you bend it. IMPORTANT When the stopper assembly is installed into the fuel tank, the top of the pressure tube (the tube you just bent) should rest just below the top of the fuel tank.
Page 21: Throttle Control System Installation
ThroTTlE CoNTrol sysTEM iNsTallaTioN you'll NEEd ThE folloWiNg ParTs froM ThE KiT: q () 8" (457mm) Pushrod Wire with Z-Bend q () .5mm Hex Wrench q () Adjustable Pushrod Connector with Nut and Grub Screw you'll NEEd ThE folloWiNg Tools aNd suPPliEs: q Thin C/A q Electric Drill q # Phillips Head Screwdriver...
Page 22: Elevator Control System Installation (Push-Pull Option)
q Install the Z-Bend in the pushrod wire into the outermost hole in your engine's throttle arm, slide the pushrod wire through the hole that you drilled in the front of the fuselage, then reinstall your engine. IMPORTANT Depending on the engine you're using, it might be necessary to make a shallow bend in the pushrod wire to achieve perfect alignment, or to prevent the pushrod wire from hitting the side of the engine mounting box.
Page 23 IMPORTANT This section details the installation of the push-pull rear mounted elevator control system. Use this option if you are using a heavier engine on the high end of the recommended size range. Mounting the servos in the back of the fuselage will help balance the aircraft by off-setting the added weight of the larger engine.
Page 24 q Temporarily thread one M3 hex nut and one 3mm clevis onto each end of one 8-/2" (26mm) threaded pushrod wire. q Centre the elevator servo and install a servo horn onto the servo, making sure that the servo arm is centred and points toward the bottom of the fuselage.
Page 25: Elevator Control System Installation (Pull-Pull Option)
ElEvaTor CoNTrol sysTEM iNsTallaTioN (Pull-Pull oPTioN) you'll NEEd ThE folloWiNg ParTs froM ThE KiT: q (2) Stranded Cables q (8) Crimp Collets q (2) M3 x 70mm Threaded Rods q (4) M3 Flat Washers q (4) Nylon Adjustable Control Horns q (4) M3 Lock Nuts q (4) Threaded Couplers q (4) M2 Hex Nuts...
Page 26 q Slide one M3 flat washer onto the threaded rod and up against the lock nut, then push the threaded rod up through the control horn mounting hole. Slide a second M3 flat washer onto the threaded rod, then thread one M3 lock nut onto the threaded rod and tighten it firmly, making sure that the threaded rod is centred.
Page 27 q Enlarge the hole in each side of a servo horn that is 3/4" (9mm) out from the centre of the servo horn, using a 5/64" (2mm) diameter drill bit. q Install one Z-Bend coupler into the hole in each side of the servo horn that you enlarged.
Page 28: Rudder Control System Installation
IMPORTANT It's important that both elevator halves track evenly together throughout the entire range of deflection. If one elevator half moves more than the other, this will cause the aircraft to roll when it pitches up or down during flight. Looking from the back of the fuselage at the trailing edge of both elevator halves, slowly move the elevator halves up and down several times (using the transmitter control stick) to ensure that both elevator halves track evenly together throughout the entire range of deflection.
Page 29 q Thread one 3mm lock nut onto the M3 x 70mm threaded rod so that the base of the lock nut is -3/6" (30mm) away from the end of the threaded rod. -3/6" (30mm) q Slide one M3 flat washer onto the threaded rod and up against the lock nut, then push the threaded rod through the control horn mounting hole.
Page 30 q Temporarily thread one M2 hex nut and one 2mm clevis onto each of the two threaded couplers, then feed the plain end of each of the two lengths of stranded cable through the slots in the fuselage and into the servo compartment. q Snap each clevis into the hole in the adjustable control horns, then firmly tighten the two hex nuts up against the clevises to lock the threaded coupler into place.
Page 31: Aileron Control System Installation
ailEroN CoNTrol sysTEM iNsTallaTioN you'll NEEd ThE folloWiNg ParTs froM ThE KiT: q (2) 2-3/8" (60mm) Threaded Pushrod Wires q (4) M3 Flat Washers q (2) M3 x 50mm Machine Screws q (2) M3 Lock Nuts q (2) Nylon Adjustable Control Horns q (4) M3 Hex Nuts q (4) Metal Clevises - 3mm Thread q () Heat-Shrink Tubing...
Page 32: Cowl Installation
q Slide one M3 flat washer onto one M3 x 50mm machine screw, then push the machine screw up through the control horn mounting hole. Slide a second M3 flat washer onto the machine screw, then thread one M3 lock nut onto the machine screw and tighten it firmly.
Page 33 1: aligNiNg ThE CoWl PRO TIP The Yak 54 ARF includes a clear mock-up cowl that can be used to make it easier to locate the necessary cutouts for your engine and muffler prior to actually cutting the fiberglass cowl. This is great for locating and transferring the initial cutouts to the fiberglass cowl;...
Page 34: Flying Wires Installation
q Remove the cowl from the fuselage, then measure forward from each of the lines that you drew to mark the back edge of the cowl to the centre of the predrilled hole in each of the cowl mounting blocks. Make a note of these measurements for the next procedure.
Page 35 q Cut away the covering material from over both sides of the three flying wire bracket mounting holes in the horizontal and vertical stabilisers. One mounting hole is located in the vertical stabiliser, 5/8" (6mm) down from the top of the stabiliser and 3-/8"...
Page 36: Final Assembly
IMPORTANT When installing the metal eyelet onto the mounting bracket that's installed onto the fuselage in the procedure below, you will need to install the machine screw from the top of the mounting bracket. q Install one metal eyelet onto the mounting bracket that's installed on the fuselage, using one M3 x 10mm machine screw, two M3 flat washers and one M3 lock nut.
Page 37 q Set the canopy onto the cockpit deck and align it. When aligned properly, the edges of the canopy should fit into the recess around the perimeter of the cockpit deck. It may be necessary to trim the edges of the canopy slightly for a perfect fit.
Page 38: C/G And Balancing
C/g aNd balaNCiNg IMPORTANT It is critical that your aircraft be balanced correctly. Incorrectly balancing your aircraft can cause your aircraft to lose control and crash! BALANCE POINT (C/G): 5-1/2" (140MM) BACk FRoM The leADIng eDge oF The WIng, MeASuReD AT The FuSelAge SIDeS. q Turn the aircraft upside down, place your fingers on the wing at the balance point, then carefully lift the aircraft.
Page 39: Aircraft Setup Information
airCrafT sETuP iNforMaTioN EXPoNENTial Exponential (Expo) softens the control feel around neutral. This is especially helpful when flying an aircraft that uses a lot of control throw. Softening the neutral point makes the aircraft fly more smoothly and makes it more likely that you won't over-control. Please note that different brands of radio control systems may call for + or - Expo.
Page 40: Preflight Check And Safety
PrEflighT ChECK aNd safETy Completely charge the transmitter and receiver batteries before your first day of flying. Check every bolt and every glue joint in the aircraft to ensure that everything is tight and well-bonded. This should include all of the control surface hinges as well.
Page 41: Trim Chart
TriM CharT After you have test-flown and done the initial trim changes to the aircraft, use this trim chart to begin trimming your aircraft. Following and adhering to this chart will result in the ability to diagnose trim problems and correct those problems using the simple adjustments shown below.
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Page 43: Product Evaluation Sheet
Your privacy is important to us. 7) Was any of the assembly difficult for you? If yes, please explain. ) Kit: Model Tech yak 54 arf # MT3173E q Yes q No...
Page 44 _______________________________ _______________________________ Post office will not deliver _______________________________ without proper postage (Return Address Here) Global Hobby Distributors Attn: global Services 8480 Bandilier Circle Fountain Valley CA 92728-860 fold along dotted line Page 44...

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