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1.
 Remove the parts from the foam
sheets gently with an X-Acto blade around the edges where they are attached
to the sheets and place them on a flat building surface. If you will paint
the plane you might leave the fuselage pieces in the sheet. You may want to
build on top of plastic or wax paper to avoid gluing the plane to the
surface. Select the slotted elevator and the 8Ó flat piece of Carbon Fiber
that matches the slot. Using CA glue, glue the strip into the slot with it
flush with the surface.
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2.
 The next step is to bevel both sides of the elevator
hinge joints. Lay the hinge area of the elevator against the edge of the work
surface or any straight edge. Place a metal ruler on top of the elevator the
same distance from the edge as the thickness of the foam. Using a new X-Acto
blade or snap knife, trim along the edge/ruler at a 45 degree angle the
length of the edge. If the foam starts to drag and rip, use a new blade. Cut
the stabilizer in the same manner.
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3.
Continue
cutting bevels in the aileron and wing control surfaces being careful to make
left and right ailerons and the matching surface on the wings.
4.
Our
preferred method of hinging is glue hinges and that is what we will reference
in these instructions. Feel free to substitute your favorite method but you
might want to do a test hinge with some of the EPP scraps in the kit to see
the benefits. Check out this YouTube video to see how easy it is to make the
glue hinge. http://www.youtube.com/watch?v=q0uK8KlR-0I
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5.
 Using the contact glue (UHU or
Welders), smear a thin coating of glue on the points of the bevels you have
just cut. Start with the elevator and stabilizer. The hinge is best when just
a fine coating of glue is used and the glue overlaps the point of the bevel
about 1/8Ó on either side. With the stab and elevator coated, let them dry to
the touch. Place the stab and elevator on the building surface with the hinge
bevel points on the top and slide the two pieces into contact. ÒSquishÓ them
together gently, but firmly. Flex the hinge to make sure it moves freely.
This joint will strengthen overnight. Continue with the hinging of the
ailerons.
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6.
 Once all the elevator and ailerons have been hinged, it
is time to do the main assembly. Working in an area large enough that the
entire outline of the plane can lay flat, take the two wing panels and test
fit them together with the 24Ó long flat piece of carbon fiber in the slot.
Make note of the surfaces that make contact and spread the contact glue on
both sides thinly and let it dry. Do not put any glue on the carbon fiber
strip at this point. Slide the wings together around the strip and press
firmly together on the flat surface so they align and attach.
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7.
While
lightly compressing the foam around the carbon fiber strip, wick CA into the
joint and use kicker to make it seal. Work your way down the joint being
careful to keep the wing flat on the building surface (this is why you
protected it with plastic/wax paper). Once you have applied glue to the top
side, flip the wing over and apply glue to the bottom side also.
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8.
Locate
the horizontal front (motor mount area) of the fuselage and fit it to the
front of the wing. Spread contact glue on both edges that come in contact and
press in place.
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9.
Attach
the rear horizontal fuselage piece to the rear of the wing in the same
manner.
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10.
Take
the stab/elevator assembly and making note of the wing hinge line (we
consider the side with the smooth joint the top and the side with the bevel
to be the bottom), attach it to the rear fuselage piece in the same way with
the hinge facing the same side as the wing (both up or both down).
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11.
 There is a third piece of flat
carbon strip in the kit which can be optionally be used to further reinforce
the nose of the plane. Just cut the carbon in half and cut slices into the
nose area as shown and CA in place.
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12.
 You should now have an outline
of the completed plane. This is a good place to paint the plane before you
attach the fuselage pieces.
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13.
Once
your paint is dry, remove the fuselage halves from the foam sheet and bevel
the rudder hinge joint. Make sure that you bevel the same sides of the rear
fuselage and rudder. Do not hinge the rudder at this time. Check the elevator
horn position and with the hinge on top, hold the rudder upright and you want
the point of the bevel on the side opposite the elevator horn. This allows
for your rudder servo to be on the side opposite the elevator servo.
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14.
 Place the wing with the smooth hinge joint down on the
building surface so the V bevel is facing up. Find the fuselage bottom and
test fit it into the notches on the outline. Smear glue on the two pieces and
attach the fuselage bottom in place making sure it stands perpendicular to
the horizontal surface and the motor mount notch faces forward.
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15.
  Find the two thin (3mm) wedge
shaped tail stiffeners. These are glued to the bottom of the fuselage at a 45
degree angle to form a triangle cross-section with the fuselage bottom and
horizontal outline and even with the rear fuselage bevel. This will prevent
the tail from twisting in flight, so it is important to complete this step
flat on the building board to maintain the alignment. There are small
alignment holes in the bottom fuselage and rear horizontal tail. You can put
round toothpicks into these holes to help align where the corners of the tail
stiffeners should go. The large end of the wedge should face the front/wing
end. Dry fit the wedge in place so you have an idea of where the glue should
be spread and attach one of the thin wedge shaped pieces to each side of the
rear fuselage. This is a good place to take a break and let all the glue
strengthen.
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16.
  Take the plywood aileron servo
bellcrank (bowtie shaped) and glue it to the existing nylon servo arm using
CA. Rough the surface of the nylon servo arm with sandpaper first. Position/align
the center hole of the plywood bellcrank concentric with the screw hole in
the nylon servo arm. If you are using the 9 gram HXT900 servo included in our
completer kit you will find alignment holes in the bellcrank that either the
.032Ó z-bend rods or #1 screws can be used to align the bellcrank. We have
cut the center hole to be snug on the servo arm and attach under the arm.
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17.
 With the aileron servo bellcrank mounted as shown,
install the 9
gram aileron
servo in the precut hole in the front of the plane. Note that the servo
output shaft is towards the rear and the flat side of the bellcrank is also.
Tack glue the servo in place with your preferred method, I use CA glue on the
mounting ears but other people use low temperature hot glue.
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18.
 Take your motor and mount it to the plywood disk
provided being careful not to block the notches. Set it so the wires arenÕt
in the notches either. Remove the motor and using CA glue, glue the disk onto
the front of the plane built thus far. If you are using the hexTronics 2730
motor from our completer kit the firewall has pilot holes to match the mount.
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19.
 Using the notch in the disk as a
guide, glue the fuselage top onto the plane, aligning it with the slots. Cut
the servo hole out if necessary to allow clearance over the servo arm. Glue
with contact glue.
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20.
 Using CA, glue the small foam
quarter circles (gussets) to the back of the motor disk so the curvature
matches the motor mount and the fuselage to provide more contact surface to
secure the motor disk. Two sets of gussets are provided for additional glue
area.
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21.
Glue
the fuselage doublers to the underside of the fuselage to further reinforce
this area to protect it during landings.
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22.
 Insert the
aileron control horns into the precut slots in the top of the ailerons so
they are flush with the bottom of the aileron slot and the holes are aligned
over the hinge line. (Note: the elevator horn has a notch in it to step over
the elevator spar and is different than the rudder and aileron horns. Be sure
to not use it for the ailerons. Glue in place with CA along the entire
length. These longer horns provide support to the control surfaces.
23.
T here are two ways to make the control linkages
adjustable. With the materials provided you can bend a V into the z-bend rods
which can be pinched or spread to adjust the control centering. This is
generally good enough since the alignment is only necessary when you set the
plane up initially. The second method that can be used is to buy optional
mini (to fit .032Ó wire) EZ-Connectors and cut the z-bends off the end of the
pushrod wires. Either of these methods work and only need to be done at the
servo end of the pushrod.
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24.
 Find the aileron pushrod materials. You will need 4
pieces of shrink tubing, 4 Z-bend wires and the two short pieces of carbon
rods. Use a piece of sandpaper to gently rough up (remove the gloss) the ends
of the carbon rods and the straight ends of the Z-bend wires. Put two of the
pieces of heat shrink onto a carbon rod. Place the Z-bend wire into the
middle hole on the control horn and slide the shrink tubing over the wire and
rod to hold it in place. Put the other Z-bend wire in the hole shown on
the bellcrank and slide the heat
shrink over this end. Using a pin or clamp or clothespin, center the aileron
surface to the fuselage. Adjust the carbon rod so it has equal gaps on both
ends and carefully CA the wire to the carbon rod to secure it. Follow the
same procedure on the opposite aileron linkage. Wiggle the sticks to see that
the controls move freely.
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25.
 Locate the elevator horn that is notched to step over
the carbon strip that is already in place. Glue the horn in place using CA so
the holes are aligned over the hinge.
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26.
 Hinge the rudder to the rear of the fuselage using a
contact glue hinge as done on the other control surfaces.
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27.
 Glue the rudder horn in place so that it is on the side
of the fuselage opposite the elevator horn.
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28.
 Now we will roughly balance the
plane to find the best position for the tail servos. Install the motor and
propeller and position the ESC on the front of the plane. Position the
receiver also.
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29.
 Put the elevator and rudder servos on the top of the horizontal
fuselage near the wing and holding the plane above the wing spar, slide them
front or back in order to balance the plane. You may find that you need to
also move the ESC and receiver forward to make it balance. Balancing without
the battery means you will be able to use different size batteries at the CG
point without affecting the balance. (These servo positions will depend on
the equipment you have chosen to use.) Glue the servos in place. CA can be
used, some people prefer hot glue or you can use contact glue. You want them
firmly attached.
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30.
 Connect the servos to the receiver and center the rudder
and elevator servos. Put a long control arm on each servo so that it is
pointed straight up. Using the two long carbon rods, create the rudder and
elevator pushrods in a manner similar to the aileron pushrods. Before you
complete both servo ends be sure to slip the provided pushrod supports over
the carbon rod. Use EZ Connectors or the V notch method to make them
adjustable. Depending on the position of your servos you may need to shorten
the rods. When your servo rods are in place, push the supports into the horizontal and vertical surfaces
midway down the pushrod to keep it from flexing in the middle. Trim the
supports so they donÕt extend beyond the back side of the fuselage and glue
them in place with CA, being careful not to get any near the pushrod to glue
it to the supports.
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31.
Using
Velcro, attach the receiver and ESC to the positions you determined to have
the best balance. Put a long strip of Velcro below the wing spar in order be
able to move the battery forward and back to fine tune your balance. The
Velcro will stick best to the EPP if you rub some contact glue on the area
you are attaching it to.
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32.
The
plane is now completely assembled. Route the servo wires through a slit in
the foam to the receiver side of the fuselage and connect everything in
place. Use tie wraps to gather the wires in a neat bundle.
33.
Control
throws are a matter of personal preference. Some people want lots of surface
movement to do 3D maneuvers while other people like a more docile handling
plane. The Yak responds very well to rudder movement and throws up to 45
degrees in each direction are often used. You can add exponential to your
controls to calm down the center portion of the travel. If you are going to
go for this type of aggressive throws, you might want to start with 50%
exponential until you get a feel for the plane. EPP is very durable and also
easily repaired. DonÕt be afraid to challenge yourself and learn new things.
Get out and enjoy flying.
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