A10 Warthog Manual
Contents
If you have not worked with foam before, it is strongly recommended that you read the How To section first.
1.0 Assemble the wing.
2.0 Assemble the tail.
3.0 Assemble the Fuselage
and Ducted Fans.
4.0 Assemble the Nacelles.
5.0 Align and install the tail.
6.0 Finishing options
7.0 Center of gravity
and battery compartment.
Let's get started
This is how it comes out of the box. Not shown in this picture are the cutting beds for the parts that are included. DO NOT DISCARD ANYTHING until the construction is complete, as some of these beds will be used as jigs during the construction phase.
Click picture to enlarge
When assembling the model, follow the order below.
You will also need:
- M77 spray glue
- Water spray bottle
- Masking tape
- Wax paper
- 150, 220 & 320 grit sandpaper, blocks, & sponge.
The A10 uses a one piece
wing made up of three panels, and is attached to the fuselage with 4 screws. The wing can be detached for
transportation.
1.1 Sheet the wing
Sand the top and bottom
of the three wing cores lightly to remove any
rough spots on the foam surface. Wet one
surface of a 1/32" x 4" x 36" balsa sheet with water, and spray the opposite
side with M77 glue. Place the balsa sheet on a flat surface with the glue
side facing up. Spray the wing core on the top and bottom with M77. Wait for the adhesive to get aggressively tacky.
Place the leading edge of the wing roughly along the mid line of the balsa
sheet. Carefully smooth
it over the top and then the bottom surface of the wing with the palm of
your hand. Do not apply
excessive pressure as this will bend and warp the wing. Use more
water if necessary to make the balsa more flexible and avoid splitting. If
it does split, do not worry, we will be filling in with wood filler later on. Continue with additional balsa
sheets to completely cover the top and bottom surfaces of the airfoil. Go
past the trailing edge about 1".
Click picture to enlarge
Trim the excess balsa at the wing root, the wing tip, and the aileron cutout with good quality scissors, Exacto knife, or a blade. The fine trimming can be done with a sanding block. DO NOT trim the excess at the trailing edge at this time. Epoxy a 1/16" balsa strip to the hinge face of the aileron slot and 1/32" balsa strips to the sides. Trim and sand flush.
Click picture to enlarge
1.2 Join the wings
Place the mid-wing on a flat surface. Set each outer wing panel on
blocks such that the bottom of the tip end is 2.5" above. This will provide
the correct dihedral angle. Sand each root end at an angle until you have a
flush fit, and glue in place with 30 minute epoxy. Dry fit before gluing.
1.3 Prepare and dry fit the ailerons
Sheet the top and bottom only of the ailerons with 1/32" balsa
going past the trailing edge about 1". Sand a 20 degree bevel on the
hinge face of the aileron.
Sheet the
hinge side with 1/16" balsa. Use care so as not to bend or warp the aileron
while sheeting. Trim and sand as necessary, but do not trim
the trailing edge as yet. Place two scrap pieces of 1/16" balsa spacers at
each end of the aileron cutout and sand the ends of the aileron to get a
snug fit. Sheet the aileron ends with 1/32" balsa. Remove the spacers and
tape the aileron temporarily in place with masking tape. Test for free
movement.
Click picture to enlarge
1.4 Make the servo boxes
We recommend using Hitec HS81 or equivalent servos for the ailerons.
Make two templates using file folder paper. One
template 1.5" x 10" and the other 1.75" x 1.75".
Place the long template along the hinge line of the aileron and the
short one at one end as shown in the picture below.
Remove the long template and trace out the outline of the short template
with a pencil. Score and remove the balsa
with an Exacto knife. Use a Dremel tool fitted with a drum sander or router
to hollow out the servo box to a depth of approximately 3/4". Line the
bottom of the box with 1/16" balsa. Coat the visible side of the liner
with epoxy to provide a smooth surface for the servo tape to stick.
Click picture to enlarge
1.5 Add the fixed main U/C mounts
If you purchased the retractable gear option, skip this section and
follow the instructions that came with retractable gear option.
Locate a 1/4" x 3 x 2 plywood
mount and place it as shown in
the picture below. Trace out the outline of the
plywood. Score and remove the balsa. Hollow out the foam to a depth of
1/4" with a Dremel tool. Dry fit the
mount to get a flush fit. Pour a liberal amount of epoxy into the
cutout and insert the mount. The U/C takes a lot of stress during landings,
so do not spare the epoxy.
Draw a line down the middle of each mount. Drill a 5/32" diameter hole, 1/2"
from the root end of the line. Install the U/C with the straps provided. You
may delay this step until after the final finish has been applied. Use 3"
diameter wheels (not provided) if you fly off grass. Smaller diameter can be
used if taking off a hard surface. Wheel retaining collars are provided.
Click picture to enlarge
1.6 Attach control horns
mounts
Tape the aileron in its neutral position. Position the servo in the
servo box as shown. Draw a line where the control rod should be and extend
it to the aileron. Position a 1/8" x 1" x 1" plywood control horn mount
provided, such that one side is lined up with the hinge and the piece is
roughly centered over the line. Trace out the location, score the balsa,
make a 1/8" deep cutout. Pour 6 minute epoxy in the cutout and insert the
mount.
Click picture to enlarge
1.7 Assemble the wing mount box.
Locate the upper and lower foam bed sections of the mid wing. Locate
the 1/16" plywood piece with a cutout and the 1/8" plywood piece without the
cutout. Epoxy the 1/16" piece to the top bed and the 1/8" to the bottom bed
as shown in the picture below. Cut off the rest of the bed that is not
covered by the plywood. You now have the top and bottom of the wing box.
Cover the sides with 1/16" balsa and trim and sand to conform with the
airfoil shape. Locate the mid line of the wing's mid-section and the mid
line of the upper bed piece. Position the upper bed piece and glue
with 6 minute epoxy. Sand the top flat.
Do not glue the lower bed piece as yet.
Click picture to enlarge
1.8 Trim the trailing edge
Place a straight edge against the rear face of the wing mount box and trim the excess balsa sheeting
in a straight line. Mark 6.8" chord at the wing tips. Place the straight
edge from the rear end of the wing joint to the tip mark, and with the
ailerons in place, trim the trailing edges of the outer wing panels.
Click picture to enlarge
1.9 Position the servos
and complete the wing mount box.
Make a 1/16"
channel
about 1/4" deep from the leading inside corner of the servo boxes to the
mid line of the wing.
Drill a 1/2" hole at the mid line all the way through to the
top of the wing. Attach extension cables to the servos and a Y Harness.
Position the servos in the servo boxes and route the cables as shown below.
Place a strip of masking tape over the mid 6" of the cable channel. Glue the
lower bed of the wing mount box in place. Sand the front & rear ends of the box
flat and glue the 1/16" x 2" x 4 7/8" plywood end pieces. Sand any rough
edges.
Click picture to enlarge
Locate the 1/8" x 5 7/8" x 12" plywood piece with the cutout. Mark 4 hole centers as shown in the picture below. Lay a sheet of wax paper on top of the wing mount box, and position this plywood piece on top, align and hold in place with with some masking tape. Drill four 9/64" holes all the way through to the bottom plywood plate. Locate the four 2 3/4" screws, blind nuts and nylon washers. Insert the screws from the bottom and install the 4 blind nuts. You may have to enlarge the holes in the top plate for the blind nuts to fit flush. Cover the blind nuts with masking tape to prevent glue from fouling the threads.
Click
picture to enlarge
1.10 Add the
wing tips
Cut the wing tip foam core into two equal halves. Glue each to the
two tips of the wing by aligning along the bottom to the wing profile.
Trim the excess, sand with fine paper and shape as shown below. Apply light
weight spackle all over the wing
tip to fill in the holes that occur naturally in foam. Sand smooth with fine
sand paper and paint the wing tip with two coats of 30 minute epoxy. This
will harden the surface and make it suitable for the final finish.
Click picture to enlarge
1.11 Fill and sand.
Apply a layer of the fiberglass tape to the top and bottom sides of
each wing joint, with 30 minute epoxy. Seal
all joints and seams with epoxy glue. Fill any gaps with light weight
spackle. Sand smooth when dry, and vacuum.
Click picture to enlarge
1.12
Attach the ailerons
This section should be attempted after the final finish has been
applied to the wing.
Attach the aileron control surfaces with transparent hinge tape on both
sides of the hinge. Alternatively, you can use strips of heat shrink
covering to obtain an invisible hinge line. Install the servo with servo
tape and center it. Connect the control rod between the servo control arm
and the aileron clevis with a z-bend at one end and a threaded insert/clevis
at the other. Make servo covers from1/16" balsa using the same template used for the
servo the boxes, attach with tape or heat shrink covering.
Click picture to enlarge
1.13 Wheel wells
Sheet the wheel wells with 1/32" balsa and M77 adhesive with the
balsa grain running across the width. Apply to the sides and then the top
and bottom. Trim, sand and seal all seams with epoxy. The wheels wells are
simply slid over the wing's leading edge and held in place with tape, after
the final finish has been applied. Make suitable cuts to accommodate the U/C
wire.
Click picture to enlarge
Congratulations, the wing assembly is now complete.
The A10 uses a stabilizer and two
fins. Rudder is excluded to save weight and servo, but it is easy to cut a
rudder and a servo box, in one or both fins.
2.1 Assemble the tail
Sand the three foam cores lightly to remove any
rough spots. Sheet
the stabilizer top and bottom with 1/32" balsa
sheets. Trim the excess balsa. Glue a strip of 1/16" balsa to the hinge
face. Do not sheet the ends of the stabilizer. Sheet around the leading edge and the inside surface
of the fin only at this time. Do not sheet the outer surfaces
of the fins.
Glue a strip of 1/16" balsa to the rudder hinge face. Trim the excess and
the slot where the stabilizer slides into. Insert the stabilizer into the slots of the fins
from the sheeted side, as shown in the
picture below, sanding and trimming the slots as necessary. Ensure that the
fins are parallel to each other by making the "X" dimensions the same. Mark
the protruding ends of the stab. Trim and sand flush with fin's outer
surface. Ensure each fin is vertical and square to the stabilizer. When
satisfied, glue in place with 30 minute epoxy.
Click picture to enlarge
Now sheet the outer surfaces of the fins. Glue a 1/4" balsa strip to the tip and root faces of each fin, trim and sand.
Click picture to enlarge
2.2 Dry fit the elevator
Cut the elevator to length of 20" and miter each edge by 45 degrees. Install
the elevator temporarily with masking tape. Check for free
travel.
Click picture to enlarge
Install the servos
Mark the mid-line of the stabilizer. Mark the position of the
elevator servo box on the underside of the stabilizer, about 2" to the left
or right of the mid line, using the template used for
the wing servos, and
make a 3/4" deep
cutout. Line the bottom of the servo
box with 1/16" balsa. We recommend a Hitec HS81
or equivalent servo for the elevator. Mount the servo using servo mounting tape, and route the cable through
a channel to the mid line.
Drill a 1/4" hole through to the upper side of
the stab and route the cable through it. Install a control horn block in the
elevator.
We recommend a Hitec HS55 or similar servo for the rudder. Make a servo box
in the corresponding fin, install the servo, and route the cable through
channels in the fin and stab. Install a control horn block in the rudder.
Click picture to enlarge
2.3 Fill and sand.
Seal
all joints and seams with epoxy glue. Fill any gaps with light weight
spackle or wood filler. Sand smooth and vacuum.
Congratulations, the tail assembly is now complete.
Click picture to enlarge
3.0 Assemble the fuselage and ducted fans
3.1 Install the ducted fan mounts
Cut the mid section blank in half and use this as a cradle to hold the
fuselage.
Locate the 1/8" x 2 1/8" x 6 3/8"
and 1/8" x 2 1/8" x 10 1/2" plywood motor mounts and the foam mid-section of
the fuselage. Mark the mid-point of each motor mount, on one long edge. Mark
the mid-point of the cross section at the rear end of the fuselage
mid-section. Dry fit at each stage before gluing. Glue as
shown in the picture below with epoxy. Shim with balsa if necessary. The mid-point marks on the mounts
should line up with the center line of the fuselage, and the mounts should be
square with the sides of the fuselage. Clamp in place until set. Use a scrap
balsa piece between the clamp and the foam to avoid denting the foam.
Click picture to enlarge
3.2 Attach the wing
Sheet the front face of the wing slot with 1/16" balsa.
Drop the wing assembly, complete with the wing retaining screws and blind
nuts, into the slot, making sure that it sits flat against the fuselage.
Make indentations in the foam to clear the wing mount screws, if necessary. Make a mark at
the mid point of the
front end of the fuselage mid section. Square the wing to the fuselage by
making the "X" dimensions equal. Mark the position, remove the wing, apply a
liberal coat of 30 minute epoxy to the top, re-seat and re-check the
alignment. Use weights. Allow the glue to set. Unscrew the 4 wing
retaining screws and remove the wing and the wax paper. You should now have
a perfectly aligned wing. Use a Dremel tool to hollow out the foam under the
cutout in the wing mount plate to make a radio compartment about 1" deep.
Line the bottom with 1/16" balsa. Cover the top of the liner with a thin
layer of epoxy. The receiver can be attached to the liner with Velcro tape.
Click picture to enlarge
3.3 Attach the tail cone
Using the same method, align and glue the tail cone in place. Square the
tail cone to the wing by making the "Y" dimensions equal as shown in
the picture below. Use wax paper to keep the tail cone from becoming glued
to the rear end of the wing mount box. Make sure the top of the tail cone
and mid fuselage are in line with each other by placing a straight edge as
shown in the picture. Sand the mating faces of the foam if necessary. Sheet
the exposed front and rear ends of the tail cone with 1/16" balsa. Do not
worry if there are minor misalignments at the joint as these will get sanded out later.
Click picture to enlarge
3.4 Attach the nose cone
Glue the nose cone, making sure it is correctly centered and aligned. Cut
and position the canopy and trace it's outline on to the foam. Tape the fuselage to the cradle
and the work surface,
sand the nose cone to shape with 100 grit
paper and finish with 220 and 320 grit. Leaving the area where the canopy
sits, round out all the edges. Leave the flat area at the tip, as is. Clean
the sandpaper often with a wire brush.
Click picture to enlarge
3.5
Sheet the fuselage.
Lightly sand the whole fuselage to remove any uneven spots especially around
the glue joints. Vacuum to remove any dust from the fuselage and the work surface. Place masking tape on the motor mounts and wing seat. Spray the
whole fuselage and some 1/32" balsa sheets with M77 adhesive. Lay the
sheets such that you avoid any seams in the curved parts of the fuselage.
Allow the sheets to extend beyond the nose
about 1". At the point where the nose cone starts converging, slit the
balsa into strips where necessary and tack each to the nose
cone. As long as the balsa is attached to bare foam, do not worry if the
strips overlap each other, because we will be sanding all that out in a
minute. Use water spray to soften the balsa, and more M77 if necessary.
Do
not get too close to the bare foam with the M77 because the propellant will
dissolve the foam. Continue all around the fuselage, the nose and the tail
cone, except the area where the tail will be glued. Try not to trap any air bubbles under the balsa
sheeting. Make relief cuts
where necessary.
Click picture to enlarge
Sand the nose cone with 100, 220, and 320 grit paper until all the overlaps are invisible. Sand the rest of the fuselage to remove any overlaps or rough spots. Glue 3 layers of 1/4" scrap balsa to the flat end of the nose tip and sand to shape. Use lightweight spackle to fix any imperfections and sand smooth with 320 grit paper. Paint the nose area with thinned down 30 minute epoxy to prevent the balsa strips from lifting over time.
Click picture to enlarge
3.6 Attach the nose wheel
If you purchased the retractable gear option, skip this section and
follow the instructions that came with retractable gear option.
Glue the 1/8" x 1" x 1 1/2" plywood piece
to the hardwood nose wheel insert. Place the wheel insert along the
mid-line of the fuselage, 14" forward from the front of the wing slot,
as shown in the picture below. Trace out the outline of the insert and make a
cutout so that 1/8" of the insert sticks out. Pour epoxy in the cutout
and glue the hardwood block into place. Drill a 5/32" hole 3/8" from the
front and 1/2" from the side of the nose wheel mount. Assemble the nose wheel as shown
in the picture below.
Click picture to enlarge
Make a servo box for the HS81 steering servo 2.5" back from the wheel. Line the bottom of the servo box with 1/16" balsa and coat the visible surface with a thin layer of epoxy. Drill a 1/2" hole from the servo box to the radio compartment. Install a HS81 servo using double sided servo tape and attach the control linkage. Make a servo box cover from 1/32" balsa.
Click picture to enlarge
3.7 Install Ducted Fans and ESCs
(hardware need for this section is not included)
Position the ESC as shown in the picture, and secure with a cable tie wrap. Mounting the ESCs
outside the fuselage ensures adequate ventilation and keeps them running cool.
Drill
a 1/4" from the ESC to the radio compartment for the power leads.
Place the ducted fan on the mounting brackets and square it with the
fuselage. Drill 9/64" holes and use screws and nuts to attach it. Turn the
fuselage bottom side up and drill one hole 1/4" from the edge of the plywood
as shown, through to the ducted fan shroud. Secure with a screw and nut.
Repeat with the other ducted fan.
Click picture to enlarge
3.8 Fill and sand
Seal
all joints and seams with epoxy glue. Fill any gaps with light weight
spackle or wood filler. Sand smooth when dry and vacuum.
Congratulations,
the fuselage assembly is now complete.
4.1 Assemble & sheet the Nacelles
Glue the main tube at the seam by aligning the inside of the tube. If
the outside is uneven, it will be sanded afterwards. Glue the seam of the
nozzle in the same manner. Sand the outside surfaces to remove any uneven
areas and rough spots.
Glue the main tube to the nozzle by aligning the inside edge as much as
possible. Sand the outside smooth especially around the joints and seams.
Sheet the main tube with 1/32" balsa and M77 adhesive using, allowing the
balsa sheet to extend past the nozzle's rear end, but do not
sheet the nozzle yet. At the point where the nozzle starts to converge in,
slit the balsa sheet into strips approx 1/4" to 1/2" wide. Tack down each
strip, allowing the strips to overlap, working in a circular manner around
the nozzle. Sand out all the overlaps with 100 grit paper and finish smooth
with 320 grit.
Click picture to enlarge
4.2 Install the Nacelles
Position the nacelle behind the ducted fan shroud and align it with the
shroud. Temporarily hold it in place with masking tape. Mark the three
points where shown. Make two cutouts as shown below, to clear the mounting
lug and the plywood mounts. Slide the Nacelle over the shroud for a snug
fit. The nacelles are held with a decorative electrical tape around the
intake lip, after the finishing has been applied.
Click picture to enlarge
Congratulations, the Nacelle assembly is now complete.
5.0 Align and install the tail
5.1 Prepare the tail
Attach the wing and place the model bottom side up in the cradle. Position the tail
at the end of the fuselage tail section, and mark the location where the servo
cable exits the stabilizer.
Drill a 1/2" hole from this point to the radio
compartment. Attach a suitable servo extension and fish it through to the
radio compartment.
5.2 Install the tail
Dry fit the tail
with masking tape and sand as necessary. Sight from the rear of
the model to see if tail is level with the wing. Sand the seat if necessary.
Make the "X" dimensions the same and the tail will be square to the
fuselage. When satisfied, mark the location. Glue with 30 minute epoxy. Tape in place and re-check the
alignment. Allow the glue to set, then using fresh glue, build an
epoxy fillet all around the tail/fuselage joint.
Click picture to enlarge
Congratulations, the Tail installation is now complete.
Click picture to enlarge
6.1
Options
Since the model is completely covered with balsa sheeting, you have several
options to personalize the final finish. The colors and design are limited
only by your imagination, creativity and building skills.
- Heat shrink covering - we recommend using low temp heat shrink
covering such as Polycover, Econokote, Superkote, etc.
- Paint over Balsa - make sure that the paint is foam friendly
or mask all exposed foam areas.
- Fiberglass and paint - use 0.75 oz fiber glass cloth and finish
with paint of your choice.
Click picture to enlarge
7.0 Center of gravity and battery compartment.
7.1 Preparation
Before balancing the model, all components need to be installed,
except the battery. The location of the battery
compartment is not pre-determined because we will use the battery or
batteries to help balance the model. Once balanced, the battery compartment
location will be marked and a compartment and hatch will be built. The
Center of Gravity is 2 3/4" back from the leading edge of the wing mount box.
Tape a 1/4" dowel along the CG line on the underside of the wing box. Place
a wooden block or box under the wing such that the model sits as a see-saw
on the dowel. Place the battery pack/s on top of the fuselage and move it
back and forth until the model is balanced. Mark the position of the battery
compartment.
7.2 Build the battery compartment.
Cut a battery compartment on the side of the fuselage. Make a cutout in the
bare foam for the battery pack. Line the inside of the compartment with 1/16"
balsa. The battery/s can be held secure with Velcro tape. The hatch cover
can be made from 1/16" balsa hinged on one side with tape and held in place
with a suitable latch or rare earth magnets. Make air intake and exit holes
to cool the battery. Drill a 1/4" hole from the battery compartment through
to the radio compartment for the power leads. Alternatively, you can cut the
battery compartment under the canopy for a completely concealed compartment.
7.3 Wire the power plant
Connect the power set up for 3S or 6S as shown in the diagram below and bench
test.
Click picture to enlarge
Congratulations the model is now complete and ready for the test flight!!