AJ Aircraft ARS 300 User manual

67'' AJ ARS 300
Assembly Instructions

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Up Your Game! Fly AJ Aircraft
AJ Aircraft thanks you for your purchase. Top grade materials and precision assembly have been used to make
this a top quality aircraft. Following the directions closely will assure you many hours of thrilling flight. Two
years of design, development, and testing has gone into this airframe. We hope you’re as happy with it as we
are!
WARNING!
AJ Aircraft’s extensive testing ensures a high quality kit that has gone through many stages to provide you with
a safe, reliable, airframe. Poor assembly will lead to an unsafe model, therefore the instructions must be
followed closely. Should you have any questions, please do not hesitate to contact us. The safe operation of
this model is your responsibility and yours alone. If you are a beginner or have never flown a model of this
size and power you should attempt it with the help of an experienced pilot. This product should not be
considered a toy, but rather a sophisticated, working model that functions much like a full-scale airplane.
Because of its performance capabilities, this product, if not assembled and operated correctly, could cause
injury to you or spectators and damage to property.
This aircraft should be flown in accordance to the AMA safety code.It is highly recommended that
you join the Academy of Model Aeronautics in order to be properly insured and to operate your model at
AMA sanctioned flying fields. If you are not willing to accept all liability for the use of this product please
return if to the place of purchase immediately.
AJ Aircraft does not accept responsibility or liability for damages resulting from use of this product.
Before starting assembly, read through the entire set of instructions to familiarize yourself with the process.
If there’s ever a question, contact AJ Aircraft. 734-244-4015

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Contents
Inspection................................................................................................................................................................................ 2
Features ..................................................................................................................................................................................3
Recommended Items for Completion.....................................................................................................................................3
Tools Needed ..........................................................................................................................................................................4
Covering ..................................................................................................................................................................................4
Wings ......................................................................................................................................................................................5
Landing Gear...........................................................................................................................................................................9
Fuselage ................................................................................................................................................................................11
Horizontal Stabilizer..............................................................................................................................................................11
Elevator.................................................................................................................................................................................12
Rudder...................................................................................................................................................................................16
Electric Motor .......................................................................................................................................................................19
Cowl ......................................................................................................................................................................................20
Radio Installation & Setup....................................................................................................................................................22
Inspection
We believe we offer the highest quality kits available. However, you may find some minor blemishes,
fractures or joint separations in the construction of our models. Many of these can be easily repaired by
backing up the joint with balsa sheet or hard balsa sticks without affecting the performance or appearance of
the aircraft.
Take the time to inspect the components of the aircraft. Inspect the fuselage for any interior joints that may
have loosened as a result of shipping & handling.

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Features
Specs:
•Wing Span - 67"
•1900 watt
•6s-8s LiPo
•Radio - 5 channel with 4 high torque servos
What's in the box:
•Pre-hinged and glued ailerons.
•Pre-hinged elevator and rudder ready to be
glued.
•Carbon fiber main and tail landing gear.
•Carbon fiber main wing tube.
•Carbon fiber reinforced landing gear mount.
•Color matched fiberglass wheel pants and
gear cuffs.
•Foil Wing Bags.
•Optional Side Force Generators (SFGs).
•Light weight foam wheels.
•Complete hardware package.
•G-10 control horns.
•Dual ball links and turnbuckles for all
connections.
•This model is set up to use 4 servos. One on
each aileron, one for the elevator and one
for the rudder using a pull-pull cable.
Recommended Items for Completion
•Power
oAJ Aircraft –AJ5220-20P/375KV 6S
oMezon 120 ESC
o6s 5000 mah LiPo packs
oXoar 21x10 prop, 20x10
o75mm (3”) Spinner
•Aileron Servos
o2x 250 oz/in Metal Geared
(Hitec HS-7955TG Recommended)
o2x 6” Servo Wire Extensions (to receiver)
o2x 1.25” Servo Arm for 3D Aerobatics
(Or a heavy-duty servo arm for sport flying.)
•Rudder Servo
o1x 250 oz/in Metal Geared
(Hitec HS-7955TG Recommended)
o2.5” Double Servo Arm
•Elevator Servo
o1x 250 oz/in Metal Geared
(Hitec HS-7955TG Recommended)
o1.25” Servo Arm for 3D Aerobatics
(Or a heavy-duty servo arm for sport flying.)
o1x 24” servo wire extension
•Radio System
o5 channel full range radio system
oPower Switch
oReceiver Battery or Speed control with BEC
oVibration padding for receiver and receiver
battery.

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Tools Needed
Blue Painters Masking Tape
Thin CA Glue
30 Minute Epoxy or Polyurethane Glue
Denatured Alcohol
Paper Towels
Removable Thread Locker (Loctite 242, Blue)
Metric & SAE (fractional) Allen Wrenches
Hobby Knife & Fresh Blades
Covering Iron (Trim Iron)
Electric Drill w/ Assorted Small Bits (1/16”,
5/64”)
Small Flat Blade & Phillips Screwdrivers
Sandpaper (150-220 Grit)
Pliers
Small Flat File
Small Round File
Clamps
Measuring Tape & Ruler
Covering
The covering on your airframe may have developed loose areas through temperature and humidity changes
between manufacturing and shipping. This may also occur during the summer heat. The covering may require
retightening a few times during your first summer of flying.
Take a few minutes to go over all of the seams making sure all edges are secure, then proceed to shrinking any
area that may need tightening. (Use an iron on all seam edges. Use a heat gun on open areas and sheeted
areas. An iron can be used in open and sheeted areas but hold the iron slightly above the surface. You don’t
want press the covering into the wood. Using an iron sock will reduce scratches.
•All airframe components are covered in genuine Ultracote covering.
•Origin Scheme (White HANU870, Orange HANU877, Midnight Blue HANU885, Silver HANU881)
•Fusion Scheme (White HANU870, Pearl Purple HANU847, Fluor Lime HANU893, Pearl Charcoal HANU846, Silver HANU881)
At 200-220°F (93-104°C) the adhesive on UltraCote® becomes active
allowing the covering to be attached to the model. While 220° will fully
bond the covering to the model it is well below the temperature that
causes UltraCote® to shrink.
At 300°F (149°C) the initial shrinking of UltraCote® begins.
At 350°F (176°C) UltraCote® reaches its maximum shrinking point. Raising
the temperature above this point will not cause further shrinkage.
Use as little heat as needed. Using too much heat may cause reshrinking
issues later.
Pro Tip - If the iron you're using does not display the actual temperature,
here is a tip that will ensure your iron is properly set.Water boils at 212°F.
Allow your iron to warm up at a medium setting. When the iron reaches its
stabilized temperature, carefully pour a few drops of water on the iron's
surface. Adjust the temperature until the water just begins to boil off. This
method is surprisingly accurate and is generally within 10° (of the exact
application temperature of 220).

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Wings
The ailerons hinges are already glued into the wings.
Firmly tug at each hinge point to ensure the hinges are
installed properly.
Carefully locate the aileron servo pocket. (Shining a light
through opposite side of the wing will help highlight the
pocket location.) Use a covering iron and seal the
covering around the edges of the opening before cutting
the covering. Use a new hobby knife blade to cut though
the covering.
Carefully locate the aileron control horn slots. Use a
covering iron to bond the covering in the area the control
horn will sit. Trim the covering away to expose the slots.
Try to avoid cutting into the bulsa surface below the
covering.
Test fit the control horn halves in the slot individually,
then as an assembly. They should fit snug. File the slot if
needed.
Check the alignment of the control horn to the hinge
center line. The linkage hole in the control horn should
be aligned with the hinge centerline.
With the control horn in position apply painter’s masking
tape around the control horn base. Put the tape up to
the base edge. Not under or over it.

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Assemble a ball link rod end to the control horn using a
supplied machine screw and nylon lock nut. Assembling
the ball link rod end to the control horn at this step will
help keep the control horn halves parallel during
installation later.
Remove the control horn leaving the tape in position.
Using a new hobby knife blade and lightly cut through the
covering but not into the balsa sheeting.
Cut inside the tape edge about 1/16”.
Use sand paper to roughen the lower portion of the
control horns on both sides. Roughen one side of the
base plate. This will help the epoxy bond to the control
horn parts.
Apply epoxy to the slots in the aileron. Use a pin to help
push some epoxy in.
Apply epoxy to the control horn assembly and insert it
into the aileron slots.
Wipe away excess epoxy using a paper towel soaked with
denatured alcohol. Use an upward rolling motion as you
wipe the excess epoxy to lift it from the surface. This
helps reduce smearing the epoxy.

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Check the alignment along the hinge line as you did when
you test fit the control horn. Reposition as needed.
Allow the epoxy to partially cure. Peel away the masking
tape after the epoxy is securely holding the control horn
in place and still soft enough to easily remove the tape.
Set the wing aside and let the epoxy fully cure.
Connect the servo to a receiver and power supply. Turn
on your transmitter. Set trim and sub trim to zero. Install
a servo arm on the servo approximately perpendicular to
the servo side. Use the transmitter’s sub trim to make it
perpendicular.
Gently snap off the servo wire installation string. Do not
pull it out of the wing. Attach the servo wire to the
installation string and gently pull the wire through the
wing as you insert the servo into the wing.
Connect a servo extension wire to the servo lead if
needed. Use a safety clip to secure the connection.
Insert the servo into the pocket with the drive spline
towards the front of the wing. Pre-drill for the servo
mounting screws using a 1/16” drill. Remove the servo
and apply a drop of thin CA glue into each mounting
screw hole. This will harden the wood around the screws
and provide a more secure installation. Allow the CA glue
to dry before reinstalling the servo.
Assemble the connecting rod to a servo arm ball link and
to the control horn ball link. Notice that one end of the
connecting rod is a left hand thread and the other end is
a right hand thread. Screw the connection rod into each
ball link equally. (A small drop of oil may make help the
threads cut into the ball link.)

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Check the length of the assembly to the servo arm to
estimate the length. When you get close to the correct
length connect the ball link to the servo arm with a socket
head screw, washer and nylon lock nut. (Always adjust
the connecting rod length with the servo powered up and
centered.)
At this point the aileron may not be aligned with the
wing.
Adjust the connecting rod to align the aileron and the
wing. Because of the left and right threads, the length of
the rod can be adjusted without disconnecting it from the
servo or the control horn.
Blind nuts for the side force generators are already
installed in the wing tips. Use the holes in a spacer plate
to help locate the holes in the wing tips and the side force
generators. Trim away the covering.
Assemble the spacer plate and the side force generator to
the wing with the supplied thumb screws.

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Landing Gear
Install the landing gear with the thicker portion of the
airfoil to the front. Add a drop of thread locker to a
socket head screw. Insert the socket head screw and
washer through the landing gear into the blind nuts
located inside the fuselage.
Fit the filler block to the bottom of the landing gear. You
may need to sand a cove down the center of the block to
fit the landing gear without rocking.
The filler block can be held in position with strips of
covering material, or packing tape over the joints.
Slide the cuffs over the landing gear and secure with self
tapping screws. Be carefull you don’t break the screws.
If the screw seems to be difficult to insert use a drill to
open up the hole. You may also choose to use a silicon
adhesive (RTV) to secure the cuffs in position. Apply a
bead of adhesive on the landing gear just above the
mounting holes and slide the cuff over the adhesive.
File a flat on the wheel axel for the wheel collar set screw.
(Making it perpendicular to the wrench flats may help
during installation and tightening later.) Slide the wheel
and collar on the axel and tighten the set screw.

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Slide the wheel and axel into the wheel pant. Make sure
the wheel is centered and has ample clearance around
the tire. Trim the inside edge of the wheel pant as
needed. Rotate the axle so the collar set screw flats are
accessable.
Insert the axel throught the hole in the landing gear and
secure with a nylon lock nut.
Drill 1/16” pilot holes into the wheel pant.
Use self threading screws to secure the wheel pants.
Position the tail wheel so the hinge joint between the
mounting bracket and the tiller arm are aligned with the
rudder hinge center line. Mark and drill 1/16” pilot holes
into the bottom of the fuselage for self threading screws.
Add a drop of thin CA glue into each hole to harden the
wood before securing with screws.
The tail wheel tiller will be fastened to the rudder with a
self threading screw after the rudder is installed.

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Fuselage
Apply thin CA glue around the joints of the fuselage
core, firewall, fuselage formers, and rudder servo
tray to strengthen the joints. Allow glue to wick
down into joints but be careful to not allow CA glue
to drip or puddle on covering material. Periodically
inspect joints as you fly your airplane. Vibration and
repetitive extreme maneuvers may cause joints to
loosen over time.
Locate the wing positioning holes and cutouts in the side
of the fuselage. Using a covering iron, adhere the area
around the openings in the fuselage side then trim away
the covering.
At the tail of the fuselage locate the elevator servo
mounting slot. Using a covering iron, adhere the covering
around the openings in the fuselage side then trim away
the covering over the servo pocket.
There is a large opening which can be cut out if additional
motor cooling is required. Use a covering iron and seal
the covering around the edges of the opening before
cutting the covering.
Horizontal Stabilizer
Slide the horizontal stabilizer through the fuselage
pushing it all the way forward. Center it side to side.
(Install the horizontal stabilizer without the elevator
attached.)

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Install and center the main wing tube. Look at the plane
from the back forward to make sure that the horizontal
stabilizer is parallel with the wing tube. If the stabilizer is
not aligned use shims or sand inside the pocket until it’s
parallel.
Push the horizontal stabilizer all the way forward in the
pocket. Position the stabilizer parallel to the main wing
tube. Measure from each corner of the stabilizer to the
canopy latch. Adjust the stabilizer until the
measurements are equal on both sides. (Install the
horizontal stabilizer without the elevator attached.)
Extra time spent aligning the stabilizer will go a long way
to improve the flight characteristics of your airplane.
When the horizontal stabilizer is positioned glue it in
place with thin CA glue. Wick glue in on both sides, top
and bottom. The use of an applicator tip is suggested to
control the flow of thin CA and get it exactly where you
want it. It is not necessary to cut the covering from the
center of the stabilizer. Gluing to the covering provides
enough strength.
Elevator
Roughen up the jointer plate for the elevator halves with
a piece of sand paper so the epoxy will adhere better.
Test fit the elevator joiner plate to each elevator half.
Insert the joiner plate into both halves and look down the
hinge line. It should be straight. If not use a small file
and adjust the slots a little at a time. (Do not glue it yet.)

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Before you cut the covering for the elevator control horn
make sure you have the correct elevator half. (If you cut
open the servo pocket in the left side of the fuselage
make sure you are working with the left elevator half.)
Install the elevator control horn using the same process
used when assembling the aileron control horns.
Use a covering sealing iron to bond the covering in the
area the control horn will sit. Trim the covering away to
expose the slots. Try to avoid cutting into the bulsa
surface below the covering
Test fit the control horn halves in the slot individually,
then as an assembly. They should fit snug.
Check the alignment of the control horn to the hinge
center line as you did with the wing. The linkage hole in
the control horn should be aligned with the hinge
centerline.
With the control horn in position apply painter’s masking
tape around the control horn base. Put the tape up to
the base edge. Not under or over it.
Assemble a ball link rod end to the control horn using a
supplied machine screw and nylon lock nut. (Assembling
the ball link to the control horn at this step will help keep
the control horn halves parallel during installation.)
Remove the control horn leaving the tape in position.
Using a new hobby knife blade lightly cut through the
covering but not into the balsa sheeting. Cut inside the
tape edge about 1/16”.
Use sand paper to roughen the lower portion of the
control horns on both sides. Roughen one side of the
base plate. This will help the epoxy bond to the control
horn parts.
Apply epoxy into the slots in the elevator. Use a pin to
help push some epoxy in. Apply epoxy to the control
horn assembly and insert it into the slots.

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Wipe away excess epoxy using a paper towel soaked with
denatured alcohol. Use an upward rolling motion as you
wipe the excess epoxy to lift it from the surface. This
helps reduce smearing the epoxy.
Check the alignment along the hinge line as you did when
you test fit the control horn. Reposition as needed. Allow
the epoxy to partially cure. Peel away the masking tape
after the epoxy is securely holding the control horn in
place and still soft enough to easily remove the tape. Set
aside and let the epoxy fully cure.
Insert hinge pins into the elevator halves and the
horizontal stabilizer. Test fit pieces together and make
adjustments so you get a good fit between the elevator
and the stabilizer. Check the hinge gap and the gap at the
counter balance.
A small round file can be used to give the hinges some
clearance. Cleaning out the holes will also help you close
up any gap in the hinge line. Turn a 1/8” drill into the
holes by hand.
Hold half of the elevator aligned to the leading edge of
the stabilizer and ensure the opposite elevator half is also
aligned at the leading edge. Sand or shim the elevator
joiner plate until both halves are aligned.
Apply petroleum jelly (Vaseline) to the center hinge pin
portion of each hinge. This will help prevent glue from
getting into the hinge when gluing then into the elevator.
Avoid getting petroleum jelly on the barbed portion of
the pin. If you do clean it off with alcohol.
Use painter masking tape to prevent glue from getting
where you don’t want it.

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We suggest using 30 minute epoxy for the elevator
jointer plate and hinges.
(Polyurethane glue, Gorilla Glue may be used for the
hinges. Add a drop of water to each hinge hole, then a
few drops off using polyurethane glue. This type of glue
is activated with moisture.)
•Begin the final assembly of the elevator by adding
epoxy to the horizontal stabilizer hinge holes then
insert the hinge pins. Use a pin to push the glue into
the holes.
•Add epoxy to the joiner slot and hinge holes of one
half of the elevator then partially slide it onto the
hinges.
•Insert the jointer plate through the fuselage then into
the elevator half.
•Add epoxy to the joiner slot and to the hinge holes of
the second elevator half then slide it onto the hinges
and jointer plate.
•Push both elevator halves into position and wipe
away any epoxy that has squeezed out.
•Move the elevator up and down to make sure it has
full travel. It won’t hurt to apply additional
petroleum jelly to the hinges.
•Tightly tape the gap between the horizontal stabilizer
and the elevator counter balance while the glue and
epoxy dry.
You may also use wide sticks and clamps to hold the
halves aligned.
Carefully remove “masking”tape at the jointer plant
before the epoxy fully sets. But do not remove the tape
at the stabilizer and elevator counter balance until epoxy
is fully cured.
Attach a 24” servo extension onto the elevator servo lead
and use shrink wrap or a safety clip to secure the
connection.
Install the servo with the spline shaft towards the front of
the airplane. Pre-drill for servo mounting screws using a
1/16” drill. Install the servo with the wood screws that
came with your servos. Remove the screws and servo.
Apply a drop of thin CA glue into each screw hole. This
will harden the wood around the screws and provide a
more secure installation. (Allow the CA glue to dry before
reinstalling the servo.)

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Connect the elevator servo to a receiver and power
supply. Turn on your transmitter. Set trim and sub trim
to zero. Install a servo arm on the servo approximately
perpendicular to the servo side. Use the transmitter’s
sub trim to make it perpendicular.
Reinstall the servo. Assemble a connecting rod and ball
link and to elevator ball link. Check the length of the
assembly to the servo arm when the elevator is level with
the horizontal stabilizer. Once the correct length of the
assembly is found connect it to the servo arm using the
provided machine screws washer and lock nut.
(Turn on the transmitter, receiver and servo while making
adjusting to the connecting rod. This will keep the servo
in its correct position.)
Rudder
The pull-pull system will use the hardware provided in
the rudder parts bag.
Use sand paper to roughen up the control horns so the
epoxy will adhere better. Assembly the control horns
with a ball link and brass cable eye. Thread the cable
eyes about half way into the ball link.
Cut the rudder covering to expose the control horn slots
on both sides of the rudder as you did for the ailerons
and elevator. Test fit the control horns, mask off the area
surrounding the control horns and use a fresh knife blade
and cut the covering as you did with the ailerons and
elevator. Try to avoid cutting into the bulsa surface
below the covering

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Tests fit the control horns to the slots and align with the
hinge line. The control horns should be symmetrical
about the hinge line. Make sure the control horns are
square to the center of the rudder.
Use 30 minute epoxy to glue the control horns in place.
Check the alignment, peal the masking tape away and set
aside for the epoxy to cure.
Test fit the rudder and adjust the hinge holes to minimize
the gap between the rudder and the vertical stabilizer.
Make sure you maintain maximum deflection. Check for
clearance at the top of the vertical stabilizer. When you
are satisfied with the fit glue the hinges in as you did with
the elevator.
Connect the rudder servo to a receiver and power supply.
Turn on your transmitter. Set trim and sub trim to zero.
Install a servo arm on the servo approximately
perpendicular to the servo side. Use the transmitter’s
sub trim to make it perpendicular to the side of the servo.
Install the rudder servo into the fuselage and pre-drill for
servo mounting screws using a 1/16” drill. Install the
servo with the wood screws that came with your servos.
Remove the screws and servo and apply a drop of thin CA
glue into each mounting screw hole. This will harden the
wood around the screws and provide a more secure
installation. (Allow the CA glue to dry before reinstalling
the servo.)
Tread the brass cable eyes about half way into the ball
links.
Start the cable assembly at the servo end inside the
fuselage. Thread on 2 crush sleeves and the brass cable
eye. (If wish to add shrink wrap over the connection,
thread it on first.)

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Loop around the cable eye and go back through a crush
sleeve.
Loop around and back through the crush sleeve again.
Adjust the loops and crimp the sleeve with the non-
serrated surface of standard plyers. Slide the tail through
the second crush sleeve and crimp.
Pull the slack out of the cables and make sure the cables
cross once inside the fuselage. Connect the ball links to
the rudder control horn.
Tape the rudder in position aligned to the vertical
stabilizer. With the servo powered up and centered
repeat the crimping process on the rudder end of the
cable. Before you crimp the crush sleeves make sure the
cable is not tangled at the servo end. Pull the cable snug.
You do not need to make the cable guitar string tight.
Remove the tape and adjust the cable lengths to center
the rudder by turning the cable eyes into the ball links.
Center the tail wheel tiller arm to the rudder. Use a self
threading screw to connect the tail wheel to the rudder.
Leave the tiller arm loose to prevent binding.

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Electric Motor
The motor mounting holes are pre-drilled in the firewall
at a 75mm bolt circle (53x53mm square). Blind nuts have
also been installed.
The firewall is about 85mm (3.35”)” from the front edge
of the cowl. Check this dimension to determine the
length of the motor spacers you may need for the motor
you will be using. Allow for 2-3mm space between the
prop backer place the face of the cowl.
We used 11.2mm spacer for the AJ5220-20P/375KV 6S
motor.
Add a drop of thread locker to the screw threads when
mounting the motor.
A 75mm (3”) spinner will fit the cowl.
Use nylon zip ties to secure the ESC to the bottom or side
of the motor box. We recommend putting a small piece
of foam between the ESC and motor box to dampen
vibrations.