Carl Goldberg GBGA0055 User Manual
Wingspan: 68”
Length: 61”
Weight: 7.5-8.5 lbs.
Engine Size: 2-cycle .60 -.90
4-cycle .90 -1.20
KIT K-55
INSTRUCTIONS
If there’s an aerobatic subject that can challenge the thrill of the Goldberg Ultimate, it’s this Extra 300! The Extra’s generous
moments, light wing loading and strong airframe make it an excellent airplane for the aerobatic pilot, whether he is learning
his first maneuvers or is an unlimited class competition flyer.Yet with all it’s aerobatic potential, this is still a very well-behaved
aircraft, making takeoffs and landings a breeze.And when it comes to engines
, please note: bigger is not better. A good .60
will do an excellent job. A larger than recommended engine may overly stress your model, causing structural failure.
WARNING
A radio-controlled model is not a toy. It is capable of causing serious bodily injury and property damage. It is the buyer’s
responsibility to build this kit correctly and to properly install the motor, radio, and all other equipment.The first test flights
should be made only with the assistance of an experienced R/C flyer. The model must always be operated and flown in
accordance with the safety standards of the Academy of Model Aeronautics.
Per the Federal Communications Commission, you are required to use only those radio frequencies specified “for Model
Aircraft.”
Pt. #2060 - 8/97
The Extra 300
© Copyright 1991
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ITEMS NEEDED TO COMPLETE THIS KIT
1 RADIO GUIDANCE SYSTEM (4 CHANNEL
MINIMUM REQUIRED)
1 ENGINE 2-CYCLE .60-90
4-CYCLE .90-1.20
PROPELLER (TO MATCH ENGINE SIZE)
1 3” DIAMETER SPINNER (LARGE ENOUGH
FOR PROP TO FIT WITHOUT MODIFICATION)
1 FUEL TANK TO MATCH ENGINE (12 OZ.
SHOWN ON PLAN)
1 24” SILICONE FUEL LINE
2 3” DIAMETER WHEELS
1 1-1/4” DIAMETER TAILWHEEL
1 2 OZ. BOTTLE MEDIUM CYANOACRYLATE
GLUE
1 CYANOACRYLATE ACCELERATOR
1 20-MINUTE EPOXY
1 LIGHTWEIGHT BALSA FILLER
1 1/2 x 8 x 12” FOAM PADDING
3 ROLLS OF COVERING
FUEL-PROOF PAINT FOR COWL AND
WHEELPANTS
OPTIONAL ITEMS
SCALE PILOT
PITTS STYLE MUFFLER
SMOKE SYSTEM
COMMERCIAL INCIDENCE GAUGE
NECESSARY TOOLS AND SUPPLIES
MISCELLANEOUS RUBBER BANDS
WAXED PAPER
MODELING KNIFE AND RAZOR BLADES
SANDPAPER (ASSORTED GRITS, INCLUDING
COARSE (80), MEDIUM (150) AND FINE (220-
320)
SANDING BLOCK
“T” PINS (at least 75)
BUILDING BOARD (24”x60”)
ELECTRIC DRILL
1/16” DRILL BIT
3/32” DRILL BIT
5/16” DRILL BIT
3/8” DRILL BIT
ALLEN WRENCH SET
SMALL SCREWDRIVER
MASKING TAPE
LONG NOSE PLIERS
COVERING IRON AND HEAT GUN
RAZOR SAW
SPRAY BOTTLE
SMALL SOLDERING IRON & SOLDER
10” 30°-60°-90° DRAFTING TRIANGLE
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USING THIS INSTRUCTION MANUAL
Before you start gluing and sanding, take some time
becoming familiar with the plans and looking through this entire
Instruction Booklet. It is designed to guide you through the
construction process step by step, so build in the order given in
this book. Balancing, setting up and flying the model are also
covered.
Like a full-size airplane, the Extra 300 is built from basic
structures (stabilizer, fin, wing, etc.), which are then assembled
into the complete airplane.
Special procedures or comments will usually be explained
before a step, so you will be prepared. If a step begins with a
statement like “Note,”‘Warning,”or “Important,” it is a good idea
to read through the step before doing it.
A check-off box appears at the beginning of each step .Check
these boxes as y ou b uild, so you can tell at a glance what steps
you have completed. Some steps are repeated and must be
marked twice, as in the case of the left and right wing panel.
Some of the instructions deal with general procedures.Boxes
are not needed for these sections.
HOW T O READ THE PLAN
There are two plan sheets in this kit, showing the Fuselage
(Body), the Wing, and the Tail Par ts. Everything on the plan is
drawn to full-size and shape and shows how the finished parts
fit together.
The plan is drawn to show the model completely assembled,
but as a result, the areas inside or underneath are covered up,
making it hard to understand how these parts fit together.
Therefore, for clarity, some par ts are drawn with hidden lines,
others with breakaway views, and some are entirely removed
from the structure and shown separately.
For example, on the fuselage, the left side of the completed
model has been removed to show the details inside.Sometimes
a surface is broken away to reveal the detail behind or
underneath.Dashed lines indicate details that are hidden behind
or under another part of the surface.
The model is made from four varieties of wood:balsa, bass,
birch, and various plywoods. Each kind of wood has its own
characteristic
end grain pattern
(as viewed from the end) which
has been drawn on the plan.Y ou can easily use these end grain
patterns to identify what kind of wood is shown for a part, if you
are in doubt.
HOW T O USE THE PLAN
The plan is used in several ways. The wings, stabilizer, and
fin are assembled directly over the plan. Each wood part is
matched over its corresponding location printed on the plan and
pinned in place. To prevent ruining your plan from gluing your
wings, etc. to it, cover the area you are working on with waxed
paper.
The paper the plan. is printed on can expand or contract
slightly with changes in temperature or humidity .Because of this,
a preformed part such as the notched wing trailing edge may not
exactly match the plan.This is no problem, as slight deviations
in the outline or size will not noticeably affect flight perf ormance.
Because the fuselage plugs together and is self-aligning, it is
not built directly over the plan. As you assemble the fuselage,
you will find the plan helpful in identifying parts and how things
fit together.
The plan also shows the installation of a typical radio, battery
and all remaining equipment and hardware needed to complete
the model. By referring to the examples shown, you should be
able to install your own radio, etc., even if it is not the same as
what is shown on the plan.
IDENTIFYING PARTS
Parts for the wing are bundled together;likewise, parts for the
tail assembly are also grouped. Die-cut plywood and balsa
sheets of common sizes are bundled together, so they are less
likely to be damaged during shipping and handling.
The various screws, hinges, and fittings are packaged in
plastic bags.
PREPARING FOR ASSEMBLY
Set a flat, warp-free pinning board on your work bench. Any
material that accepts pins, such as insulation board, soft
plywood, or dry-wall (sheet rock) will work.
Important:
any
warps or bends in the pinning board will result in wings or
tail surfaces that are also warped or bent, making your
model more difficult to fly.
Make sure that the pinning board
is flat by laying a straight edge across it. You may be able to
correct a warped board by shimming its low areas.
Position the area of the plan (such as the stabilizer) on which
you are going to build ov er the pinning board and tape it in place
so the plan lays flat and wrinkle free.
Place a sheet of waxed paper or plastic kitchen wrap ov er the
work area to prevent the C/A glue from sticking to y our plan and
ruining it.
CONSTRUCTION TIPS
In assembling your model, the follo wing tips will prove helpful.
IMPORTANT: ALWAYS READ A FEW STEPS AHEAD.This
will alert you to coming instructions and will help you plan
accordingly.
You may find it convenient to empty all of the small parts from
the hardware bags into a common container, such as a
margarine tub.This will help you find items quickly.
When drilling any 1/16” holes in balsa, you may find it easier
to twist the drill between your thumb and index finger. This
procedure allows more control in positioning the drill on the
center mark.
Punch out only the die-cut (D/C) parts you need as you
proceed. This will help you keep track of parts, especially the
small ones.
After completing each section of the aircraft, you may w ant to
go back and reglue the joints, just in case some area has been
missed. Be careful not to use too little glue, which will leave the
model weak or too much glue, which can make the model hea vy .
Properly glued joints are important to the overall strength of the
model. Medium C/A glue is recommended for most parts of the
assembly, although Jet Epoxy may be used when more time is
needed for careful placement.
INTRODUCTION
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PARTS IDENTIFICATION
WOOD PARTS
Be careful Men removing parts (such as fuselage sides) from the
die-cut sheets.Long parts are fragile until glued into a structural
unit. If necessary, use a razor knife or razor saw to assist in the
removal of parts from the sheet.Sometimes a little trimming and
sanding can improve parts, Mere desired. Save scrap until the
model is completed, in case a part is missing or damaged. Also,
scrap is used in some building steps.
ABOUT THE WOOD IN THE KIT
We strive to supply good quality materials in your kit.Wood parts
are inspected with regard to the function they will serve. If an
imperfection is spotted in a scrap corner of a die-cut sheet and
doesn’t affect actual parts, the sheet is considered acceptable.
Also, internal stresses in wood are reliev ed as it is cut into parts.
These relieved stresses ma y cause some parts to bow. Bows in
wood parts (such as leading edges) readily straighten out as they
are glued into a structural unit
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HORIZONTAL STABILIZER CONSTRUCTION (5 Steps)
1. Collect all of the items you will need to construct the
HORIZONTAL STABILIZER. They include:
(1) D/C SHEET 5517 3/16” BALSA PT. # 1331
Includes:
CENTER PLATFORM
(5) 3/16 x 5/16 X 28” BALSA STICKS PT. #4371
(4) 1/16 x 3 x 30” BALSA SHEETING PT.#4539
2. ■■ Lay the horizontal stabilizer portion of the plan over the
building board and place the waxed paper over the
plan.You will also need “T” pins, an X-Acto
®
knife with
a #11 blade, and a razor saw.
■■ Pin the CENTER PLATFORM over the plan.
■■ Cut a 3/16 x 5/16”balsa stic k and glue it to the platform
with medium CA, pinning it over the plan.
3. ■■ Trim the remaining 3/16 x 5/16” balsa sticks to fit the
plan, pinning and gluing as you go. In cutting the
diagonal trusses for the tail, trim them to fit well.If a bit
oversize, don’t force them in place. The pieces should
fit before gluing
4. ■■ Place a 1/16 x 3 x 28” balsa sheet flush to the trailing
edge (T.E.) of the stabilizer and mark the sheet width
onto the stab sticks.
HINT: In selecting the sheeting for the stab , choose the firmer
or heavier wood. whenever sheeting any surface, is
helpful to lightly sand both sides of the sheet before
using medium C/A. Also, whenever joining sheeting,
“truing”the edges to be glued with a long sanding b lock
and prefitting can make a big difference.
■■ Remove the sheet and apply medium C/A to the stab
sticks up to the sheet-width mark
■■ Place the glued stab frame over the 1/16” sheeting,
making sure that the trailing edge is flush with the
sheet.
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5. ■■ Glue the remainder of the stab frame and install
another 1/16” balsa sheet. Then, tr im the sheeting to
the profile of the stab.
■■ Spin the cut-off around and glue to the remaining space
on the frame.
■■ Flip the stab over and sheet it as shown above.
ELEVATOR CONSTRUCTION (4 Steps)
1. ■■ Collect all of the parts needed to build the two
ELEVATOR HALVES.They include:
(5) 5/16” sq.x 16”BALSA STICKS PT. #4370
(1) BIRCH PLY D/C SHT. 5518 CONTAINING:
(4) HORN MOUNTS PT. #3481
(1) D/C BALSA SHT. 5520 CONTAINING:
(2) HORN MOUNT CORES PT. #3332
(2) D/C SHT. 5517 (BALSA) CONTAINING:
(1) BALSA CORNER GUSSETS PT. #3331
(1) BALSA HORN MOUNT CORES PT. #3331
2. ■■ Laminate the two 1/32”PL YWOOD HORN MOUNTS to
the 3/16” and 1/16” BALSA CORES.
■■ Make two such assemblies, one for each elevator half.
THIS COMPLETES THE HORIZONTAL STABILIZER. PUT IT
ASIDE FOR NOW;YOU WILL NOT NEED IT UNTIL YOU ARE
READ Y T O INST ALL THE HINGES.
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3. ■■ Place waxed paper over the elevator section of the
plan.
■■ Trim and glue the 5/16” square balsa sticks over the
plan, pinning as you go.
4. ■■ Glue the HORN MOUNT ASSEMBLIES and the
CORNER GUSSETS into the frame.
1. ■■ Collect the items needed to construct the VERTICAL
FIN.They include:
(3) 3/16 x 5/16 x16” BALSA STICKS PT. #4369
(2) 1/16 x 3 x 18” BALSA SHEETS PT. #4538
2. ■■ Cover the fin portion of the plan with waxed paper.
■■ T rim the 3/16 x 5/16”balsa sticks and pin over the plan,
gluing as you go.
VERTICAL FIN CONSTRUCTION (4 Steps)
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3. ■■ Place the 1/16” balsa sheeting flush with the Leading
Edge (L.E.) and mark the width of the sheet onto the
frame.
■■ Apply Jet to the frame, up to the width marks, and
permanently install the sheeting. Pin down to insure a
flat assembly.
■■ Trim the sheeting and use the drop-off to cover the
remaining area of the fin side, trimming to the profile of
the fin as you go.
4. ■■ Flip the fin over and repeat the sheeting operation, as
illustrated.
THIS COMPLETES THE VERTICAL FIN CONSTRUCTION.
PUT IT ASIDE UNTIL YOU ARE READY TO INSTALL THE
HINGES.
1. ■■ Collect all of the parts you will need to construct the
RUDDER.They include:
(3) 5/16” sq. x 16”BALSA STICKS PT. #4370
(1) D/C BALSA SHT. 5517 PT. #3331
CONTAINING:
(1) 3/16” HORN MOUNT
(2) D/C BALSA SHT. 5520 PT. #3332
CONTAINING:
(1) 1/16” HORN MOUNT
2. ■■ Laminate the three horn mounts as shown, making
sure that the 3/16” horn mount is in the middle.
RUDDER CONSTRUCTION (4 Steps)
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3. ■■ Cover the RUDDER por tion of your plan with waxed
paper and pin the laminated horn mount assembly over
the plan.
4. ■■ Trim, glue, and pin the 5/16” square balsa sticks over
the plan as shown.
NOW GATHER THE HORIZONTAL STABILIZER, THE
ELEVATOR HALVES, THE FIN AND THE RUDDER AND
PROCEED TO THE NEXT SECTION, “ROUNDING AND
HINGING.”
ROUNDING & HINGING (11 Steps)
1. ■■ Collect all of the items needed to complete this section.
In addition to the following kits parts, you wiII need a
small drill, drill bits, a modeling knife, a sharp pencil, a
sanding block, and fine and medium grit sandpaper.
(9) JET HINGES PT. #1667
(1) D/C PLY SHT. #5519 PT. #3482
CONTAINING:
(1) ROUNDING TOOL
(1) “R”BEVEL TOOL
(1) “AE”BEVEL TOOL
(1) CG NYLON CENTERLINE MARKER PT. #1425
2. ■■ From the plan, transfer the hinge locations onto the
rudder and the elevator halves.
■■ Next, transfer the hinge locations from the rudder to the
fin, and from the elevators to the stab.
NOTE: Leave a 1/16” gap between the air balance on both the
rudder and the fin.
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3. ■■ Using the centerline tool, scribe the centerline onto the
rudder post, the fin post, the hinge line of the stabilizer,
and onto both elevators
4. ■■
Carefuly cut a slot approximately 1/2” deep and slightly
wider than the hinge, using your favorite knife blade.
5. ■■
After all slots have been made, mark the center of your
hinge and insert a pin (see illus.) This will hold the
hinge in place while sliding the matching part (aileron,
etc.) onto the JET HINGE.
DO NOT GLUE!
■■
With both surfaces hinged and assembled, check the
alignment. For good control response, the hinge gap
should be as small as possible, but should
allow for full deflection when needed.
Remove the hinges.
6. ■■ Assemble the two bevel tools and install a str ip of
medium grit sandpaper, as shown.
7. ■■ Using the tool marked “R,” bev el the rudder-side of the
hingeline to a point at the centerline.You may want to
bevel near the air balance with a knif e , if you can’t use
the tool in the corner.
■■ Using the tool marked “AE,” bevel the elevators to a
point at the centerline.
8. ■■ T emporarily hinge the rudder/fin and the stab/elev ators
to check the surface alignment and to round the
perimeter of the assemblies.
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9. ■■ Assemble the Rounding Tool and install a piece of
medium sandpaper.
10. ■■ Using the tool, round the perimeter of the fin/rudder and
the stab/elevators.
■■ When you are satisfied with the shape, use a piece of
fine sandpaper to remove the deep scratches.
11. ■■ Finish sand all of the tail par ts, using a sanding block
and fine sandpaper.
HINT: Sanding will cause gaps at the joints to fill with balsa
dust. Use this to your advantage by putting a drop of
thin C/A glue into the gap. Then sand after the glue
dries.
■■ Separate the fin from the rudder and the elevators from
the stabilizer.
THIS COMPLETES THE CONSTRUCTION OF THE TAIL
SECTION PARTS.PUT THEM ASIDE UNTIL YOU ARE READ Y
TO A TTACH THEM T O THE FUSELAGE.
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THE INSTRUCTIONS WILL LEAD YOU THROUGH THE
ASSEMBLY SEQUENCE, OCCASIONALLY SENDING YOU
BACK TO REPEAT STEPS. CAREFULLY READ EACH STEP
BEFORE YOU PROCEED TO DO THE INSTRUCTION.
1. Find all the parts that you will need to build the wing.
THEY INCLUDE:
(4) 3/8" SQ. X 35" SPAR BASS (MIL #4528)
(2) SHAPED L.E BALSA (MIL #4524)
(2) NOTCHED T.E BALSA (MIL #4523)
(2) WING RIBS 2 & 8 BALSA (D.C. 5310-3325)
(2) WING RIBS 3 & 6 BALSA (D.C. 5511-3326)
(2) WING RIBS 4 & 1 BALSA (D.C. 5512-3327)
(2) WING RIBS 5 & 7 BALSA (D.C. 5513-3328)
(2) WING RIBS 1, 9 & 10 BALSA (D.C. 5514-3329)
(4) WING CENTER SHEETING BALSA
(D.C. 5515-3330)
(2) SHEAR-WEBS BALSA (D.C.5520-3332)
(2) WING JOINER PLY
(2) BELCRANK PLATFORMS PLY
(D.C. 5516-3483)
(2) DOWEL SUPPORT PLY (D.C. 5516-3483)
(1) WING SUPPORT FRT PLY (D.C. 5516-3483)
(1) WING SUPPORT REAR PLY (D.C. 5516-3483)
(1) WING SUPPORT TIP PLY (D.C. 5516-3483)
(1) SERVO PLATFORM PLY (D.C. 5516-3483)
(1) DOWEL GUIDE PLY (D.C. 5509-3480)
(2) INBOARD T.E. BALSA (MIL #4526)
(5) 1/16" x 1/4" x 24" CAPS BALSA (STK #4525)
(2) AILERONS BALSA (MIL #4527)
(6) 1/16" x 2-3/4" x 35" BALSA (SHT #4888)
(4) 1/16" x 2-1/2" x 35" BALSA (SHT#4887)
(1) 3/4" x 33" NYLON FABRIC (NYL #5210)
(1) 5/16" x 4-3/4" DOWEL BIRCH (MIL #1759)
(2) .063" x 20-3/4" AILERON WIRE (MTL #1230)
(2) .063" x 7" THREADED ROD (MTL #1270)
(2) AILERON BELCRANKS (NYL #1410)
(2) AILERON BUSHINGS (MTL #1182)
(2) 2-56 NUT (MTL #1115)
(2) 2-56 x 1/2" MACHINE SCREW (MTL #1041)
(2) #2 WASHER (NYL#1461)
(4) NYLON SNAP-NUT (NYL #1138)
(3) 1/16" I.D.x 1" BRASS TUBE (BRS #1376)
(1) AILERON COUPLER BLOCK (NYL #1427)
(1) 2-56 x 3/4" MACHINE SCREW (MTL #1042)
(1) 2-56 x 1/8" MACHINE SCREW (MIL #1040)
(1) SNAP LINK (NYL #1405)
(8) FLEX POINT HINGES (NYL #1449)
(1) C.G.CENTERLINE TOOL (NYL #1425)
CONSTRUCTING THE WING (35 Steps)
14
NOTE:IF USING AN ENGINE LARGER THAN A.60 2-CYCLE,
YOU WILL WANT TO FOLLOW THE INSTRUCTIONS FOR THE
TWO SERVO OPTION, WHICH ARE FOUND IMMEDIATELY
AFTER THE WING SECTION.
NOTE:Y OU WILL BE BUILDING TWO WING HAL VES.DO NOT
BUILD BOTH HALVES OVER THE SAME SECTION OF THE
PLAN. FOLLOW STEPS CAREFULLY TO AVOID
CONFUSION
2. ■■ Cut the vying plan along the dotted line.Position the left
wing plan overlapping the right plan, aligning the
arrows as shown. Pin or tape the plan to the building
board and cover with waxed paper,
3. ■■ Lay a shaped LEADING EDGE over the plan and cut
the angle at the centerline. Repeat this step on the
other L.E.
■■ Next, place the notched TRAILING EDGE over the over
the plan, aligning the notches to insure that y
ou cut the
correct end. Cut the angle at the centerline and then
repeat this step on the other notched T.E.
■■ Referring to the plan, cut the inboard T. E. parts to the
correct length and angle.
4. ■■ Wrap a piece of fine sandpaper around the 5/16”
DOWEL and sand the wing pin notch into the angle-cut
end of the shaped L.E.
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