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   Thank you for your purchase of the Extreme Flight RC Jeremy Chinn designed 
Matchless Yak-55SP profile ARF!  We are honored to have worked with Jeremy on this 
project to deliver a very high performance, high quality product.  Jeremy has been 
involved in prototype testing and we have listened to his suggestions and are very excited 
about the outcome.   
The Chinn Yak (as it is called by the Profile Brotherhood) was released previously as a 
kit and quickly became a favorite among the Pro Bros.  There are numerous build threads 
and videos of this aircraft on the Pro Bro site (www.theprofilebrotherhood.com).  When 
looking for a new profile to produce the Chinn Yak was at the top of our list and 
arrangements were made with Jeremy for Extreme Flight RC to produce an ARF version 
of his beloved design. 
The Chinn Yak excels at all things 3D!  Enormous control surfaces provide extreme 
authority in pitch, roll and yaw axis maneuvers.  You may want to experiment with 
slightly higher exponential values than you are accustomed to until you get used to this 
amount of responsiveness.  The Chinn Yak is an excellent platform to hone your 3D 
skills with and its unlimited performance capability will provide hours of excitement for 
the 3D enthusiast.

 

        

Tips for Success-Please read before beginning assembly!!!

 

1.

 

Read the instruction manual thoroughly before starting assembly. 

2.

 

We are very pleased with the level of craftsmanship exhibited by the workers in 
our factory.  However, these are mass produced models.  As with any ARF, take a 
few minutes to go over the model and add CA to high stress areas or any joints 
that appear to need more glue.   

3.

 

Take a few minutes and go over the covering with a hot iron.  Make sure all edges 
are sealed and pay special attention to thin stripes. 

4.

 

Decals-

 clean your airplane with glass cleaner and a paper towel before starting to 

apply the decals.  Mist the area where the decal will be applied with glass cleaner 
or water mixed with a little bit of soap.  Use scissors to remove the decal from the 
sheet.  For best results cut as close to the edges of the decal as possible.  Position 
the decal in place and use a credit card or rubber squeegee to push the excess 
liquid from under the decal and allow to dry.  You may need to secure the edges 
of the decal with masking tape to prevent them from rolling up until the solution 
has dried and evaporated. 

 
 

 
 
 
 
 
 
 
 
 
 
 
 
 

 
 

Summary of Contents for YAK-55SP

Page 1: ...YAK 55SP Profile ARF Instruction Manual Copyright 2008 EXTREME FLIGHT RC Ltd ...

Page 2: ...n Yak is an excellent platform to hone your 3D skills with and its unlimited performance capability will provide hours of excitement for the 3D enthusiast Tips for Success Please read before beginning assembly 1 Read the instruction manual thoroughly before starting assembly 2 We are very pleased with the level of craftsmanship exhibited by the workers in our factory However these are mass produce...

Page 3: ...3 Assembly 1 The first step is to use a sharp hobby knife to remove the covering from the wing slot stab slot and servo openings in the rear of the fuselage as shown in the pictures ...

Page 4: ...ering iron or sharp hobby blade to remove the covering from the center of the stab DO NOT GLUE THE STAB IN AT THIS TIME 4 Locate the elevator and the composite control horn and base Open the slot in the elevator to accept the control horn and place the base on the horn and insert in the slot Use a fine tipped marker to outline the base and then remove the horn assembly Use a blade to remove the co...

Page 5: ...ces pointing toward the rear of the fuselage Once in the slot rotate the elevator into position Now slide the stab into position Re check alignment and glue in place with 30 minute epoxy Once dry slide the elevator onto the hinges and secure with thin CA Be sure to leave enough gap to get maximum deflection ...

Page 6: ...r of the fuselage Check to make sure it is properly aligned to the fuselage sides and at 90 degrees to the horizontal stab as well as flush with the rear of the fuselage Sand or shim the slot as needed for proper alignment When satisfied glue in place with 30minute epoxy ...

Page 7: ...n that will glue into the rudder for best adhesion 8 Slide a small wheel collar over the tailwheel wire and insert the tailwheel wire into the hole in the aluminum mounting bracket Use a set of pliers to bend the wire to 90 degrees as shown making sure the bend is perpendicular to the portion of the wire where the tailwheel will mount 9 Drill a hole in the bevel of the rudder to accept the wire ju...

Page 8: ... hinges and into position and secure with thin CA Be sure to leave enough gap to be able to get maximum deflection 11 Secure the aluminum bracket to the bottom of the fuselage with 2 screws and tighten the collar against the bracket ...

Page 9: ...d to insure a wood to wood bond between the wing and fuselage 13 Remove the wing from the fuselage and use an old soldering iron or sharp hobby knife to remove the covering from the center of the wing Use some denatured alcohol to remove any remaining ink 14 Slide the wing into position just a few inches short of its proper location Mix up some 30 minute epoxy and apply to the exposed wood at the ...

Page 10: ...ohol Re check alignment and then set aside to dry Once dry fill in any gaps with thick CA 16 Locate the 2 ailerons 2 composite control horns and 2 base plates Open the covering over the slot on the bottom of the aileron and insert the control horn into the base and into the slot Use a fine tipped felt marker to trace the base plate and remove the covering from this area ...

Page 11: ...trude through the top surface Scuff the portion of the control horn that will glue into the slot and insert the horn into the base plate and secure to the aileron with 30 minute epoxy Repeat for the other aileron 18 Slide the ailerons onto the hinges and into position and secure with thin CA ...

Page 12: ...4mm bolts washers and nuts 20 Scuff the inside of the spats with sandpaper and glue the plywood plate to the spat with 30 minute epoxy as shown Repeat for the other spat 21 Once dry drill a hole through the ply plate and spat as shown to accept the threaded portion of the axle Slide the threaded portion of the axle through the spat and through the landing gear leg and secure with a nylon insert lo...

Page 13: ... are 2 holes pre drilled in the outer layer of plywood near the front bottom of the fuselage for mounting the landing gear Locate these two holes and drill completely through the fuselage with a 5 32 bit Use the 4mm bolts nuts and washers to secure the main gear to the fuselage ...

Page 14: ...14 ...

Page 15: ...nstall the servos and then remove the screws and wick some thin CA into the mounting holes before reinstalling the screws 25 You will need to attach 24 extensions to the elevator servos to reach the radio compartment inside the wing There is a channel in the bottom of the fuselage and the extensions are routed through an opening in the lower side of the fuselage as shown ...

Page 16: ...ugh the bottom of the fuselage and out of the pre cut slot and into the radio compartment in the wing through the pre cut slot as shown 27 Locate the provided strip of Ultracote and iron it into position on the bottom of the fuselage ...

Page 17: ... also recommend the use of the Dubro Super Strength servo arms All of the linkages for the ailerons elevator and rudder assemble the same way Electronically center your servos Thread a ball link onto each end of the pushrod Insert a 2 mm bolt into a washer through the ball link and into the servo arm or control horn Secure with another washer and nut Be sure to apply a drop of Loctite to prevent t...

Page 18: ...ve proper CG Lighter engines like the 2 stroke 46 50 will need to be mounted further forward on the rails while heavier engines like the 4 stroke 82 will need to be mounted further aft We recommend installing your receiver and battery in the radio compartment in the wing opposite the engine Wrap your receiver battery in foam and place it inside the leading edge of the wing and secure with Velcro O...

Page 19: ...provided screw eyes as shown and secure each with a drop of medium CA 33 Secure the tank to the fuselage with nylon cable ties or rubber bands Be sure to place a piece of closed cell foam between the tank and fuselage side ...

Page 20: ...ot Jeremy says the ideal 3D CG is at 5 25 Below are his recommended rates and exponential preferences You may wish to start with a bit more exponential than this as the control surfaces are extremely effective High Rates Low Rates Expo Elevator 50 degrees 25 degrees 20 40 Rudder 50 60 degrees 30 degrees 30 50 Ailerons 50 degrees 30 degrees 20 40 Thanks again for your purchase of the Extreme Flight...

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