GREAT PLANES Sportster Bipe 40 User manual

Sportster Bipe 40
Instruction Manual
Engine size .35-.45
Wingspan 45 1/2"
Length 41 1/2"
Wing Area
716 sq . in.
Weight
5-61/2 Ibs.
Materials Needed to Complete the Sportster:
4 Channel radio Propeller Fuel tank
Engine Wheel collars Spinner
Fiberglass cloth/resin Wheels Covering
Engine mounting bolts Hinges Instant glue
Pushrods/clevises Wing bolts EPOXY
The Sportster Bipe
40 was designed for sport flying. This biplane design with symmetrical wings pro -
vides full aerobatic maneuverability, yet has enough wing area for docile low speed capability.
The parts are machine cut and sanded for accurate fit. Should you notice a difference in size between
plans and parts, it is usually because paper changes size with moisture.
Different types of glue may be used such
as epoxy, cyanoacrylate(instant glue) and aliphatic resin (white
glue). Build on a flat surface for straight wings and fuselage.
Please read through this step
- by - step instruction manual before you start building so you will have an
overall idea of the construction steps and to avoid mistakes. Use the plan and parts list to identify the var
-
ious parts.
WAR N I N G !
This R/C kit and the model you will build is not a toy! It is capable of serious
bodily harm and property damage.
IT IS YOUR RESPONSIBILITY AND YOURS
ALONE
- to build this kit correctly, properly install all R/C components and flying
gear (engine, tank, pushrods, etc.) and to test the model and fly
it only with experi -
enced, competent help in accordance with all safety standards and common
sense as set down in the Academy of Model Aeronautics Safety Code.
It is sug -
gested that you join the AMA and become properly insured before you attempt to
fly this model. IF YOU ARE JUST STARTING R/C MODELING, CONSULT YOUR
LOCAL HOBBY SHOP
OR WRITE TO THE ACADEMY OF MODEL AERONAUTICS
TO FIND AN EXPERIENCED INSTRUCTOR IN YOUR AREA.
Academy of Model Aeronautics
1810 Samuel Morse Dr.
Reston, VA 22090
PO BOX 788 URBANA lLLlNOlS61801 2171367 2069

BUILDING THE TAIL SECTION
PREPARE THE FIN AND RUDDER
Sandthe forward and rear sectionsof the fin
if neces -
sary for a good fit. Working over the plans, glue the fin section
pieces together. Sand both sides of the rudder.
CUT THE HINGE SLOTS IN THE FIN AND RUD -
DER; CUT OUT RUDDER FOR JOINER CLEAR -
ANCE
Draw centerlines down the trailing edge of the fin
and the leading edge of the rudder. Mark and cut the hinge
slots. Two hinges are used above the stabilizer. The third hinge
should be just below the stab and above the tail wheel strut
tab. Cut out part of the rudder leading edge for elevator joiner
wire clearance. Wait to shape the leading edge until the hole
is drilled for the tail wheel tiller arm later.
3. GLUE STAB PARTSTOGETHER; SAND THE STAB
AND ELEVATORS
Check the fit and sand the forward and rer parts of
the stab
so they fit together well. Glue them together. Sand both
sides of the stab and elevator halves.
4. DRILL HOLES IN THE ELEVATOR HALVES FOR
ELEVATOR JOINER WIRE
Draw a front to back centerline down the top side of
the stab and a centerlinedown the leadingedges of the elevator
halves. Mark the center of the elevator joiner wire. Align the
stab, elevator and joiner wire and mark the hole locations for
the joiner wire arms on the centerline of the elevator leading
edge. Drill the holes.
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5. GROOVE OUT THE ELEVATORS FOR JOINER
WIRE CLEARANCE
Cut a groove in the elevator leading edge inside of
the hole
so when the joiner wire is installed it will be flush with
the leading edge of the elevator.
Do both elevator halves.
6. TRIAL FIT THE JOINER WIRE
Temporarily install the elevator joiner wire into the
elevator halves. Check to make sure that this assembly is
aligned properly. Bend the joiner arms
if necessary for a perfect
fit.
DO NOT GLUE THE JOINER WIRE TO THE ELEVATOR
HALVESUNTILAFTERTHE PIECESARE COVEREDLATER.
7. CUT HINGE SLOTS FOR THE STAB AND
ELEVATOR
Mark and cut the hingeslots for the stab and elevator
halves as you did with the fin and rudder. See the plans for
locations. Shape the leading edges of the elevator halves to a
V’.
READ THIS FIRST BEFORE YOU START BUILDING THE
WING PANELS: It is very important that you buildstraight wings
with no warps or twists or you will get some flying characteristics
you didn’t expect! Be very carefulwhen you align the ribs, spars,
leading edges, trailing edges and sheeting at the various steps
below. All these parts should be in their correct positions before
you glue them in place. Hold or pin the parts in place, then
glue. Use the following instructions to help you build the wing
straight and warp free.
Remember: Anyone can build a wing. Only
a careful builder
can build a straight wing.
BUILDING THE TOP WING
Start the top wing by building two spars from 1/4 x
1/4 x 24 balsa, aleadingedgefrom 1/4 x1/2 x24balsaand
a trailing edge from1/4 x1/4 x 24 balsa. Use waxedpaper
on the plan. Cut the parts, fit them together and then glue
overthe plan. The top wingis built in one piece. You will
build the top wing upside down at first. Use epoxy when
you glue these pieces together in this step.
3

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2. PREPARE THE RIBS
Draw a rib alignment line down the center of each
top wing rib. Note that the three center ribs have 2 extra notches
for the cabane mounting plate. Draw rib alignment centerlines
down the back of the leading edge and the front of the trailing
edge.
3. ALIGN AND GLUE RIBS, LEADING EDGE AND
TRAILING EDGE TO TOP SPAR
Pin the top spar (the wing will be built (upside
down) over the waxed paper covered plan. Place the ribs on
the spar. Align the ribs at the positions shown on the plans.
Make sure that the three center ribs have the cabane notches
" up " as shown. Shim up the trailing edges of the ribs with the
extra 1/4 x 1/4
x 24 spars, making sure the centerlines you
drew on the ribs are parallel to the building board. When the
ribs are aligned correctly, and at 90 degrees to the building
board, glue the ribs
to the spar. Line up the lines on the ribs
with the line on the leading edge. Glue the ribs
to the leading
edge. Line up the trailing edge line
to the rib lines and glue the
ribs
to the trailing edge.
4. GLUE IN SPAR FILLER BRACE, BOTTOM SPAR
AND SHEAR WEB
Cut out the area between the spar notches on the
two end center ribs for the 1/4 x 9/16 balsa spar filler brace.
Glue in the 1/4 x 9/16 filler brace pieces from the center rib out
past the spar scarf joint on both sides of the center rib. Glue
in the bottom spar. Now cut shear web pieces from 3/32 x 3
x
24 balsa to fit between the spars at the rib bays shown on the
plan. The wing should still be shimmed up with the extra spars
throughout the building process. Use epoxy in this step.
5. ADD THE CABANE HOLDERS
Glue in the two plywood 1/4 x 1/2
x 6 1/2 cabane
wire holders with epoxy into the slots in the htree center ribs.
Make sure the cabane holders are flush with the top edges of
the ribs.
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6. ADD THE SHEETING AND CAP STRIPS
Cut the sheeting to fit first then glue in place. Glue
on the 1/16
x 2-1/8 x 24 leading edge sheeting, the 1/16 x 7/8
x 24 trailing edge sheeting and the 1/16 x 3 x 15 center section
sheeting. Do not glue the sheeting
to the cabane holders as
you will cut away this sheeting later. Cut cap strips from 1/16
x
3/16 x 36 balsa and glue them in place over the rib edges.
7. ADD 1/4 TRI STOCK BRACES
After the glue is dry, turn the wing over and pin it
down
to the building board. Use 1/4 x 36 triangle stock and cut
pieces
to fit along the length of the cabane holders as shown
on the plan. Glue this 1/4 tri
to the sheeting and to the cabane
holder. Also cut tri stock
to fit on either side of the three center
. ribs on top of the cabane holders. Glue these braces in place.
\
8. ADDTHE REST OFTHE SHEETING
Glue on the1/16
x 2-1/8 x 24leading edge sheeting,
the1/16
x 7/8 x 24trailingedge sheeting and the 1/16 x 3 x 15
center section sheeting. Glue onthe1/16
x 3/16cap strips.
9. ADDTHETRAILINGEDGE
Addthetapered3/8
x 1 x 24balsatrailing edgestock
andthe3/8
x 1 x 6taperedcentertrailingedgepiece.Cutparts
to fit first and then glue them in place. Now cut the curve in the
center trailing edge as shown on the plan and in the photo.
5

BUILDING THE BOTTOM WING
PREPARE WING RIBS
Mark all bottomwing ribs with a rib alignment center-
line. Also draw centerlines down the 1/4
x 1/2 x 24 leading edge
and the 1/4
x 1/2 x 24 trailing edge pieces. There is no top or
bottom to the bottom wing at this point.
2. GLUE THE RIBS TO THE SPAR
Build the right and left wing panels separately. Build
the left panel first. Use the extra spar as a shim at the trailing
edge as you did with the tio wing. Pin the bottom spar over the
plans. Align the ribs to the spar, shim up the trailing edges of
the ribs and glue the ribs
to the spar. Use the 1/4 x 7/8 x 3 wing
hold down block as a spacer for location of ribs #1 and #2.
(Note: These hold downs are the same size as the ones that
glue into the fuselage later.) Do not glue the hold down block
in place yet.
3. ADD LEADING EDGE, TRAILING EDGE, TOP
SPAR, HOLD DOWN AND FILLER
Align the above parts first and then glue in place
(leading edge, trailing edge and top spar). Use epoxy to glue
the hold down in place. Glue the balsa 1/4
x 5/8 x 3 filler above
the hold down and sand the it
to the shape of the rib contour.
4.
6
ADD THE SHEETING
Glue on the 1/16
x 2-118 x 24
leading edge sheeting, the 1/16
x 7/8 x 24 trailing
edge sheeting and the 1/16 x 3
x 15 center section
sheeting. Cut cap strips from 1/16
x 3/16 x 36 balsa
and glue them in place.

5. ADDTHE SHEETINGAND FILLER ONTHEOTHER
SIDE
OF THE WING PANEL
When the glue is dry, turn the wing panel over, realign
it to the board and glue in the balsa filler on the other side of
the hold down. Sand it to shape. Add the leading edge sheeting,
the trailing edge sheeting and the center section sheeting.Add
the cap strips. This completes the left wing panel for now. Re
-
move the panel from the building board when it is dry. Now
build the right wing panel by following steps 1 through
5.
INSTALLING THE WING TIPS
1. GLUE THE WING TIPS TO TOP AND BOTTOM
WING PANELS
Cut
off the sheeting and spars even with the tip rib.
Do not cut
off the leading edge! Glue the wing tips on both the
top and bottom wingslpanels. The tips should be centered on
the tip rib and the leading edge centerline. The wing tips for
the top wing will have to sanded to an angle at the top to fit
against the leading edge. Cut the tip brace pieces from the 114
scrap provided (1/4
x 3 x 11 - 7/8). Add the filler piece at the
lower end of the wing tips, top and bottom. Sand this filler to
shape later after hinging and installing the ailerons. Sand the
leading edge to the rounded shape shown on the plans. Cut
off the spars and sheetingeven with the root rib on the panels.
Cut the inner tip filler from some scrap balsa and add to
the inside
of the tip. Shape it to match the ailerons and
tip filler blocks.
INSTALLING THE CENTER
TRAILING EDGE (BOTTOM WING)
I. MAKE CENTER SECTlON/TORQUE ROD AS -
SEMBLIES
Draw a centerline down the trailing edges of the wing
panels and down the leading edges of the center sections. Cut
a groove along the centerline in the tapered
5/8 x 1 - 3/4 x 3 - 1/2
balsa center section pieces for the aileron torque rods. Notch
the center sections for backward torque rod arm movement.
Glue the brass sleeves of the torque rods into the blocks with
epoxy. Make right and left assemblies. Also notch the trailing
edge of the wing panelfor forward movementof the torque arms.
2. GLUE THE CENTER SECTIONS TO THE WING
PANELS
Use vaseline at the ends of the tube of the torque
rod
so you don't glue the wire to the wing. The rod must be free
to move. Glue the rod/center sections to the wing panels up
the centerlines.

JOINING THE BOTTOM WING PANELS
GLUE THE CENTER RIB TO THE LEFT WING
With the wing panels
" up " , glue the wedge - shaped
balsa center rib
to the root end of the left wing panel. Make
sure the wider edge of the center rib is down and that the
leading edge and trailing edge are centered on the tapered rib.
Use
5 minute epoxy.
PANEL
_
2. SAND THE CENTER RIB TO THE WING PANEL
CONTOUR
Rough cut the center rib to the wing airfoil, leaving
it about
1/8" oversize. Sand the remainder away with a sanding
block
so that the center ribedges areflush with the wing sheeting
surfaces.
3. JOINTHEWING PANELS; ADDTHEWING PLATES
Join the wing panels upsidedown. Line up the lead-
ing and trailing edges of the panels. Use a straight edge to
make sure the leading edge of the wing is straight. Block up
the wing
7/8" at the center and glue the panels together using
slow set epoxy. See the drawing on the plan. Remember the
wing is upside down
at this point! When the glue is dry, turn
the wing over and mark the aileron servo well location. Add the
1/16 x 2 x 3 - 1/4 plywoodwing plateto the bottomof the wing.
I
4. GLASS THE CENTER SECTION OF THE WING
DO NOT OMIT THIS STEP!
Doing so may result in a wing failure during flight!
Coat the area where the wings were joined with 5
minuteepoxy and use a 4 " wide strip of 6 oz. glass ornylon
cloth to reinforce the centerjoint. Saturate the cloth with
epoxy and then wipe
off any extra epoxy. The cloth strip
shouldcover both the top and the bottom
of the wingjoint.
When the epoxy is
dry, sand the center section lightly
without sandinginto the glass cloth.

PREPARE THE AILERONS
Cut the aileron stock
(5/8 x 17-1/2 tapered stock) to
length and draw a centerline down the leading edge of the
ailerons. Mark and drill the torque rod holes. Groove the aileron
for torque rod clearance. Make right and left ailerons.
2. CUTTHE HINGE SLOTS; FINAL SAND THE AILE-
RONS
Mark and cut the hinge slots into the ailerons and
the wing trailing edge. Shape the leading edge
of the ailerons
to a
“V’. Temporarily install the ailerons with hinges to check
the fit. Final sand the wing tips to match the aileron contour at
neutral. Do not permanently hinge the ailerons until after they
are covered.
BUILDING THE FUSELAGE
1. PREPARE THE FUSELAGE SIDES
,
Mark the inside of the fuselage sides “right” and
“left”. Cut out part of the wing saddle area at the rear as shown
on the plan.
STOP! If you plan to install a 4 - cycle engine, read and follow
the instructions on installation of 4
- cycle engines at the end of
this instruction book.
LEFT
2. PREPARE THE BULKHEADS
Locate the 1/4
x 3 x 2-3/4 plywood Bulkhead #1, the
Firewall. Mark the “top” of the firewall (the bottom has a slight
angle). Mark the position of the motor mount. Mark and drill the
holes for the motor mount
4 - 40 screws. Put the 4 - 40 blind nuts
, in positions in these holes you drilled. Temporarily place the
mount on the firewall with the screws. Cut the screws
off in
back of the firewall
so they won’t get in the way of the fuel tank.
Notch a hole in Bulkhead #2 for the throttle linkage. Prepare
Bulkhead #3 by drilling holes for the outer pushrod housings.
,
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3.DGLUETHEDOUBLERSTO THE FUSELAGESIDES
UsingBulkhead #1 as a spacer, install the 1/8" balsa
doublers crossgrain onthe inside of the fuselage sides. Cut the
doubler pieces from 1/8 x 3 x 36 balsa first, position andthen
glue inplace. Use slow set epoxy or thick cyanoacrylate. The
doubler should extend 1/4"beyond the position of bulkhead #3.
Trimthe doublers to the fuselage contour.
Note: Becareful when you cut the doubler stock as you need
to usewhat isleft inthe next step.
4.D BUILDTHETHREE REAR FORMERS
Make Formers #4,5 and 6 from 1/8x 1/4x 36balsa.
Usethe plans as a guide andcut the balsa to size. Glue the
parts together to make the three formers. Make push rod braces
from scrap 1/8x 3 x 36 left over fromthe doubler stock inthe
step you just did.The widths of the braces are the same as
that of each of the formers. The braces will beinstalled when
the pushrods are installed later.STOP! Did you read the4-cycle
engineinstructions ifyou planto install a 4-cycle?
DMARK BULKHEAD POSITIONS
Mark the positions of bulkheads #2 and #3 onthe
fuselagesides.Also mark the position of thebalsadashbetween
#2 and#3. Markthe positions of the cabane blocks now ifyou
wish.
6.D DRILL PUSHROD EXIT HOLES
Markanddrill the holes inthe fuselage sides for the
pushrodexits for the elevator and rudder.See the plans for
suggested positions of the pushrods to estimate the hole posi-
tions. A piece of brass tubing sharpened on the inside with an
X-Acto knife blade makes a neat,clean angled hole for tube-
style pushrods.
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