RedWing RC Yak55 User manual

Yak 55 Assembly Manual

Thank you for purchasing the RedWing RC Yak 55. We have provided you with the highest quality kit
and flight performance possible. We wish you great success in the assembly and flying of your new
RedWing RC Yak 55.
Caution!
1. You should not regard this airplane as a toy.
2. To ensure safety, please read this instruction manual thoroughly before assembly.
3. Building and operating a model airplane requires diligent practice and correct guidance. An
inexperienced flyer can cause serious injury and property damage.
4. Seek the assistance of an experienced RC pilot or model airplane club for help with assembly,
operation and maintenance to assure your flying experience is both enjoyable and safe.
5. Fly only in AMA (Academy of Model Aeronautics) approved areas.
Redwing RC warrants this model to be free from defects in both materials and workmanship from date
of purchase. This warranty does not cover any component parts damaged by use or modification. In
no case shall RedWing RC’s liability exceed the original cost of the purchased kit. Further, RedWing RC
reserves the right to change or modify this warranty without notice.
In that RedWing RC has no control over final assembly or materials used for final assembly, no liability
shall be assumed nor accepted for any damage resulting from the use by the user of the final user-
assembled product. By the act of using the user-assembled product, the user accepts all resulting
liability.
We, as the kit manufacturer, have provided you with a top quality, thoroughly tested kit and
instructions, but ultimately the quality and fly ability of your finished model depends on how you built
it; therefore, we cannot in any way guarantee the performance of your completed model, and no
representations are expressed or implied as to the performance or safety of your completed model.

Specifications
Wingspan: 73”
Wing area: 1005 in²
All up flying weight: 10½ to 12 pounds, depending on hardware and building style
Overall length: 66”
Engine: any 30 to 36cc engine (DLE 30, DLE 35, PTE 36 recommended)
Radio: 6 channel recommended (4 channel possible)
CG: 25 to 30% back from LE at root
Servos: 150 in-oz torque, metal gear. Digital servos are recommended.
Assembly
Prior to assembly, inspect entire framework. Pay particular attention to covering and seams in
covering. Temperature extremes in shipping containers sometimes cause wrinkles or loose seams to
form. Most wrinkles and loose seams can easily be fixed by taking a little time with a sealing iron or
heat gun. Persistent wrinkles are generally caused by air trapped under the covering. These can be
removed by puncturing the covering with a pin to create and escape for the air. Vibrations during
shipping can loosen glue joints. These can be repaired with CA glue.
Notes on Assembly
Assembly order is non-critical. Many steps can be done whenever the builder wants to do them. For
instance, hinging of all surfaces can be done at the same time. Same goes for control horns. They can
all be done at the same time. Installation process for both hinges and control horns will be described
once. The order described in this manual is intended to minimize the time it takes to assemble this kit.
It is recommended that the landing gear be installed early to keep the fuselage from rolling. Wheels
and pants can be installed at any time. Some builders may prefer to install the wheels and pants last,
just to keep the airplane from rolling off their work bench.

Hardware required to finish the kit
30 cc class engine with muffler (DLE-30, DLE-35 or PTE-36 recommended)
Standoffs for engine (normally included with engine)
Propeller: 19”x8” or suitable size for engine used
Spinner
Servos:
5 for flight surfaces (XQ 4013 or XQ 4016 available from RedWing RC)
1 for throttle (metal gear recommended)
Receiver: 4 channel minimum. 6 channel or more recommended
Transmitter: 4 channel minimum. 6 channel or more computerized recommended
Optical kill switch on ignition recommended (available from RedWing RC)
Battery:
3000 mah LiFe can be used for both ignition and receiver (available from RedWing RC)
If desired, a separate battery of at least 1000 mah capacity can be used for ignition.
Switch: 2 HD switches (available from RedWing RC)
Servo extensions:
Aileron: two 12” heavy duty and two 6” (available from RedWing RC)
Elevator: two 24” heavy duty (available from RedWing RC)
Throttle: 12” heavy duty (available from RedWing RC)
Servo safety clips for each extension (available from RedWing RC)
Tools, etc. required to finish model
Screwdrivers: Phillips and common
Wrenches: metric open end or box
Ball drivers or allen head wrenches
Drill with assorted bits
Pliers or crimping tool
Hobby heat gun and hobby sealing iron
Modeling knife (X-acto with #11 blade, or equivalent)
Wire cutters
Pen or marker (Sharpie, or equivalent)
Scissors
Thin, medium CA and CA accelerator
15-30 minute epoxy with mixing cups and mixing sticks
Gorilla Glue or Tightbond II for hinges (if don’t want to use epoxy)
Blue threadlock
Rubbing alcohol and wipes or paper towels
Q-tips are handy, but not a necessity
6 pound sledge hammer –not really, just checking to see if you are still reading this

Notes on radio installation
While this airplane can be flown with a simple 4 channel transmitter, it is recommended that at least 6
channel computerized transmitter be used. The 4 channel transmitter would require the use of Y-
harnesses on both aileron and elevator servos. The 6 channel transmitter allows plugging each servo
into its own channel. Servo sub trim and end points can then be adjusted to optimize the servo control
horn configuration.
At neutral, aileron servo arms should be parallel with the aileron hinge line. Elevator servo arms
should be vertical.
Turnbuckle type pushrods are included for the ailerons and elevators. Turnbuckles have a left hand
thread on one end and a right hand thread on the other. They are convenient as they allow finer
adjustments than a conventional clevis. They also allow adjustment without disconnecting anything.
However, initially they are easier to set up if you center the servo arm, center the control surface and
hold the turnbuckle up to both ball links to see how far to thread the turnbuckle in. Thread the
turnbuckle this amount into each ball link. This will have the pushrod length close to what is needed.
It can be further adjusted after installing the servo arm on the servo.
Make a point to install the turnbuckles in the same direction on all control surfaces. For instance, use
the right hand thread at the servo and left hand thread at the control horn. If they are all installed the
same way, then rotating the turnbuckle clockwise or counter clockwise has the same effect on all
control surfaces. For instance, turning clockwise shortens the pushrod and pulls the control surface
down.
Recommended control setup has control surface ball links installed on the outer hole of the control
horns and the other ball link attached at the second from the outer hole on the servo arm. Adjust
servo end point on the transmitter to give desired control throw. Rudder will need about 125% on the
servo travel to maximize throw. This will improve control resolution over using the outer holes on the
servo arm and having to reduce servo throw to less than 100%
Make sure elevator halves center to the same place. This is done by positioning the servo arms so they
are both vertical when the elevator stick is neutral. Adjust the length of the turnbuckle pushrods for
neutral elevator. Maximum throw in both directions is set with servo end point on the transmitter.
Select an inner hole on the throttle servo arm that requires servo throw of greater than 100% in both
low and high throttle directions. 120% in each direction is possible. This gives much better throttle
control than using an outer hole on the servo arm and throw of less than 100%.

Main gear is installed using nuts and bolts that are
inserted in predrilled holes. Bolts go through landing
gear cover, main gear, then fuselage bottom. Nuts
are installed inside the fuselage and accessible via the
canister tunnel. Note: remove covering from landing
gear cover at four bolt positions.
Place tail wheel bracket in positions and mark
location of the mounting holes. Note: locate the
bracket as low as possible on the tapered section at
the back of the fuselage. Location shown is too high
and will result in difficulty when setting up tail wheel
steering. It was actually installed about 3/4” lower.
Drill holes for mounting screws.
Install tail wheel bracket only. Note: wheel and
steering linkage will be installed later.

Several different types of adhesive are acceptable
for installing hinges. Epoxy, Gorilla Glue and
aliphatic resin (Titebond II) all work. One
benefit of the aliphatic resin is it cleans up with
water until it cures. A dental syringe is an
excellent tool for injecting glue into the holes.
Remove all hinges from their pre-drilled holes.
Scuff barbs on all hinges with coarse sandpaper
or similar tool.
Place a small amount of lubricant on the pin of
the hinge and flex the hinge back and forth to
coat the pin with lubricant. Lithium grease was
used in this model.
You can use the same Lithium grease to keep
your door hinges from squeaking.
Inject a small amount of adhesive into the hole in
the flying surface. Also add some adhesive to the
barbs of the hinge. Insert the hinge into the hole
until the pin is at the hinge line.

Install all hinges in the flying surface. Make sure
all hinges line up the same. If you would like,
proceed directly to installing the hinges in the
control surface at this time. Inject adhesive into
all holes and onto the barbs of all hinges. Make
sure all hinges will go in holes. Push rudder into
position.
Once all hinges have been installed, clean off
excess adhesive. Flex hinge back and forth to
help align the hinges in the holes.
Rudder hinges have been completed. Note:
minimal hinge gap and throw is bevel to bevel. If
necessary, increase gap slightly to achieve full
control surface throw.
Repeat process for elevator hinges. Note:
minimal hinge gap and bevel to bevel throw.
Repeat process for aileron hinges. Note: minimal
hinge gap and bevel to bevel throw.

Remove covering over aileron servo openings and
control horn slots. Covering can be removed by
either cutting it off with an X-acto or similar knife or
by melting it with a pencil type of soldering iron. The
soldering pencil seals the covering to the structure,
but leaves some excess that needs to be cut off.
Note slots for rudder horns near bottom of rudder.
Openings in fuselage for elevator mounting, elevator
servo and rudder pull-pull cable exit.
Slots for elevator control horns have been marked,
but not cut yet.

Assemble aileron control horns and tighten bolt.
Scuff bottom of control horns (glue area) with coarse
sandpaper for better adhesion. Inject epoxy into
both control horn slots. Apply additional epoxy to
both sides of each control horn. Insert control horns
into slots and clean up excess epoxy that oozes out of
slots.
Elevator control horns have been installed. Note:
excess epoxy has not been cleaned off yet.
Rudder uses two pairs of control horns for pull-pull
cables. The horns install directly opposed from each
other, thus will not fit unless trimmed. The horns on
the left have been marked. The horns on the right
have been trimmed. Verify both sets of horns fit
prior to gluing in place.
Install both pairs of rudder control horns with epoxy.
Pull-pull cable will be installed later.

Verify control horns have cured prior to installing
servos.
Install isolation grommets and brass bushings in all
servos. Note: brass bushings are installed from the
bottom.
Set aileron servo in position. Drill all four holes for
mounting screws. Install screws, then remove and
move servo out of the way. Place a drop of thin CA
glue in each hole to toughen threads in the plywood.
Reinstall aileron servos. Use 12” extension on servo
lead. Don’t forget to use some sort of restraint on
the connector. Restraints are commercially available.
Dental floss can be wrapped around the connector
and tied 3 or 4 times. Some people like heat shrink
tubing. If heat shrink is used, avoid overheating the
connector.
Install aileron servo. Note: servo spline is closer to
the leading edge of the wing.

Remove covering over aileron servo openings and
control horn slots. Covering can be removed by
either cutting it off with an X-acto or similar knife or
by melting it with a pencil type of soldering iron. The
soldering pencil seals the covering to the structure,
but leaves some excess that needs to be cut off.
Note slots for rudder horns near bottom of rudder.
Openings in fuselage for elevator mounting, elevator
servo and rudder pull-pull cable exit.
Slots for elevator control horns have been marked,
but not cut yet.
Prepare servo arms. Carbon fiber arms are provided
for all control surface servos. The round wheels that
come with the servos can be used. If desired,
aluminum wheels can be purchased from RedWing
RC for an additional cost. These wheels are drilled
and tapped to fit the arms. We will be using the
short turnbuckle pushrods for ailerons.
Verify servo is centered. Install control arm on servo.
Servo arm should be parallel to hinge line. Manually
center the aileron. Hold turnbuckle pushrod up to
the two ball links to see how far the turnbuckle has to
be threaded into each ball link. Thread turnbuckle
into ball links. Note: the turnbuckle has left hand and
right hand threads.
Install elevator servo with a 24” heavy duty
extension. Servo spline is closer to the rudder. Be
sure to restrain the connector on the extension.
Temporarily install servo arm and turnbuckle
pushrod. Longer turnbuckles are used on elevator
linkages.
Install elevators. Center elevator and servo. Hold
turnbuckle up to elevator ball link to estimate how
far to thread turnbuckle in. Thread turnbuckle into
elevator ball link (need to take servo arm off servo to
do this. Reinstall servo arm. Readjust turnbuckle as
required to center elevator when servo arm is
vertical.

Install rudder servo. Note: spline faces front of
airplane. Ball links should be on second to last
hole in the arm. Servo arm sweeps toward back
of airplane.
Prepare pull-pull cables. Measure distance
between ball link on rudder horn and ball link on
servo arm. This can be done by inserting a balsa
stick (anything that will fit) through the cable
outlet hole to the ball link on the servo. Be sure
to cross from one side to the other. Add ½” to
allow for ¼” thread into each ball link.
Insert cable through crimp, then to threaded
connector.
Double cable back through crimp.

Thread one end of cable onto ball link on rudder
horn. Feed cable through fuselage to rudder
servo arm.
Remove ball link from servo arm. Thread cable
end onto ball link. Reattach ball link to servo
arm. Install second cable, making sure to cross
the cables. Note: getting cables tight enough and
centering rudder is a trial and error process.
Cables need to be snug, but not “guitar string”
tight.
Loop cable back through crimp. Pull end to
shorten loop prior to crimping.
Crimp with either pliers or a crimping tool. Add
a drop of CA after crimping. Assemble both
rudder cables to the length determined earlier.

Let’s move on to the fuselage. Start by taping the
drill guide for your engine to the firewall. Align
the horizontal and vertical centerlines with the
laser marked lines on the firewall. Drill through
circles with appropriate size drill. Template
shown is for a DLE-30.
Remove template after drilling engine mounting
holes.
Install standoffs using thread lock on bolts. Note:
a 10 mm open end wrench fits on the flats of the
standoffs.
Temporarily mount engine.
Mark locations of throttle linkage and fuel line on
firewall.
Remove engine and drill holes for fuel line and
throttle linkage.

Reinstall engine without muffler and spark plug.
Install cowl.
Make template for drilling cowl holes out of
heavy paper, make cutout for bulge in cowl.
Tape template in place.
Tape will be used as a hinge.
Remove cowl. Temporarily install muffler and
spark plug on engine.
Mark location of muffler exhaust and spark plug
on template. Cut holes in template.
Remove muffler and spark plug.
Reinstall cowl and mark locations of muffler and
spark plug on cowl.
Remove cowl and cut preliminary holes. Don’t
worry about making them look perfect at this
point.
Reinstall muffler and spark plug.
Reinstall cowl. If your template was accurate,
muffler and spark plug should line up with holes.
Mark final hole sizes allowing for at least 1/8”
clearance around muffler. Clearance for spark
plug should include ignition cap.
Uninstall cowl again.

Enlarge holes per revised marks. This time
smooth edges, etc. Hole for spark plug includes
ignition cap.
Provide hole for air to exit cowl.
Test fit cowl and adjust openings if needed.
Remove cowl.
Cut hole in motorbox floor for throttle servo, just
in front of wing. Verify location doesn’t interfere
with wing alignment pin or muffler (if canister).
Drill holes in plywood plate for servo mounting
screws, then glue into place.
Circular hole aft of throttle servo is for throttle
servo wire.
Feed throttle servo lead through hole for servo,
then back out through circular hole.
Install throttle servo and throttle pushrod. Quick
link type of connector was used on the servo arm.
Note: throttle pushrod is connected to an inner
hole in the throttle servo arm.

Reinstall engine. This time use thread lock on the
mounting bolts.
Connect throttle pushrod using a quick link type
of connector.
Choke uses a ball link, mainly to clear the throttle
arm.
Brass bracket for choke guide and choke pushrod
are not included in the kit.
Install muffler with gasket. Use thread lock on
bolts.
Ignition will be held on using Velcro and a
couple of zip ties (not included with kit).
Install Velcro strips.
Cut holes through side of motorbox for zip ties.

Ignition installation completed. Note: power
lead is protected with spiral wrap (included with
engine) and goes into the radio compartment to
the battery.
If desired, the ignition battery can be installed on
the side of the motorbox.
A 3000 mah LiFe battery (available from
RedWing RC) is being used for both the radio
and ignition. It is held in place with a couple of
strips of Velcro and a strap that goes through the
motorbox side and around the battery. Verify
sheet metal screws used for attaching cover over
access hatch don’t hit the battery.
Assemble and install fuel tank. Tank is strapped
in with Velcro.
Vent line loops back over the end of the tank
prior to exiting out the motorbox bottom.
This is a 3 line tank. The other lines go to the
carburetor and fuel dot for filling and emptying
tank.
Attach covers over motorbox top and canister
tunnel.
Reinstall cowl. Upper bolts are accessed from
the canopy side. Bottom bolts are accessed from
inside cowl and are difficult to install. Exhaust
opening can be used to access bolts.
Bottom nuts and bolts can be replaced with rare
earth magnets. Use one magnet on cowl ring, one
on the fuselage. Remember to arrange magnets
to attract, not repel.

Temporarily install wheel pants.
Bolt holes are slightly oversized. Make sure
pants line up properly before completely
tightening bolts.
Add a drop of medium CA to collar of blind nut
prior to fully tightening it.
Remove wheel pants to simplify installation of
axles.
Install axles with flat sides horizontal to prevent
interference with wheel pant positioning.
Reinstall wheel pants.
File flat spots on axle at wheel collar location.
Install wheels and wheel collars.
Use wheel collars to center wheel within wheel
pant.