Carl Goldberg GPMA1993 User Manual

WARNING

A radio-controlled model is not a toy and is not intended for persons under 16 years old. Keep
this kit out of the reach of younger children, as it contains parts that could be dangerous. A radio­controlled model is capable of causing serious bodily injury and property damage. It is the buyer's
responsibility to assemble this aircraft correctly and to properly install the motor, radio, and all other
equipment. Test and fly the finished model only in the presence and with the assistance of another
experienced R/C flyer. The model must always be operated and flown using great care and common
sense, as well as in accordance with the Safety Code of the Academy of Model Aeronautics
(www.modelaircraft.org). We suggest you join the AMA and become properly insured prior to flying this
model. Also, consult with the AMA or your local hobby dealer to find an experienced instructor in your
area. Per the Federal Communications Commission, you are required to use only those radio frequen­cies specified "for Model Aircraft."

LIMITED WARRANTY

Carl Goldberg Products has inspected and certified the components of this aircraft. The company urges the buyer to perform his
own inspection, prior to assembly, and to immediately request a replacement of any parts he believes to be defective for their
intended use. The company warrants replacement of any such components, provided the buyer requests such replacement with­in a period of 90 days from the date of purchase and provided the defective part is returned, if so requested by the company.

No other warranty, expressed or implied, is made by the company with respect to this kit. The buyer acknowledges and under­stands that it is his responsibility to carefully assemble the finished flying model airplane and to fly it safely. The buyer hereby
assumes full responsibility for the risk and all liability for personal or property damage or injury arising out of the buyer's use of the
components of this kit.

INSTRUCTIONS

CARL GOLDBERG PRODUCTS, LTD.

P.O. Box 818 Oakwood GA 30566 Phone #[phone] Fax # [phone] www.carlgoldbergproducts.com

© Copyright 2004 Carl Goldberg Products LTD.

Skylark 70

ARF

Designed as a first low-wing trainer over 26 years ago it is still a terrific everyday sport plane, the Skylark 70
ARF combines docile flight characteristics with the aptitude for super-smooth, exciting aerobatics. This ARF
has been designed to keep building time to a minimum; it's 90% pre-built, with premium covering. So read
through these instructions, follow them carefully, and you'll soon be flying a terrific plane. The better you get
the more fun it gives you!

TM

NOTE: The Skylark 70 ARF colors match Midnight

Blue(885), True Red(866) and White (#870)
UltraCote®.

2

TOOLS AND SUPPLIES FOR ASSEMBLY.

 MODELING OR UTILITY KNIFE
 WORK SURFACE (24" X70")
 ELECTRIC DRILL
 1/16”, 3/32”,1/8", 5/32”, 1/4” DRILL BITS
 SMALL STANDARD & PHILLIPS SCREW-

DRIVERS

 MASKING TAPE
 NEEDLE NOSE PLIERS
 36” RULER OR TAPE MEASURE
 FLEXIBLE STRAIGHT-EDGE
 T-SQUARE
 30-60-90° x 6" TRIANGLE
 SOFT PENCIL
 A FEW STRAIGHT OR "T" PINS
 ADJUSTABLE WRENCH
 WIRE CUTTER
 OPTIONAL HEAT GUN/COVERING IRON
 ACID BRUSH

USING THIS INSTRUCTION MANUAL

Before you begin assembling your Skylark 70 ARF, take
some time to read through this entire instruction book. It is
designed to take you step-by-step through the process and
to give you added information on engine and radio selec­tion and set-up, balancing your aircraft, and flying your
model. The time you spend will speed the assembly
process and help you avoid problems.

PREPARING FOR ASSEMBLY

You will need a work area of approximately 24 x 70" which has
been covered to protect it from adhesive, as well as cuts and
other damage. Many people cover their work area with a
sheet of dry wall (sheet rock) and/or waxed paper t o pre­vent CAGlue and Epoxy from ruining the work surface.

CONSTRUCTION TIPS

IMPORTANT: ALWAYS READ A FEW STEPS AHEAD.
This will alert you to coming instructions and will help you
plan accordingly.

Using the Parts Identification section, familiarize yourself
with the various items included in your kit box.

As you work, CHECK OFF EACH STEP in the box provid­ed, so that you are sure you do not forget anything.

Do not hesitate to ask questions. Your local hobby dealer
and area flyers will most likely be happy to help, as they
want you to have a successful flying experience. You may
also receive technical assistance from Carl Goldberg
Products, Ltd. via by telephone [phone].

ADHESIVES & GLUING TECHNIQUES

CA adhesives are specially formulated to firmly glue the
plywood, hardwood, and balsa used in your model and to
withstand the vibration and stresses of high performance
flight. However, there are times, such as when you are
installing the stabilizer and fin on the fuselage and want
more set-up time for careful alignment and positioning,
then you should use epoxy.. Occasionally, you also will
want to use thin CA, which "wicks" into the surrounding
areas. Aliphatic resin glue or similar water-based glues can
also be used, but they will add to the assembly time
because they dry so much more slowly than CA glue.
Remember, when ever using any CA, you must be careful
to read instructions thoroughly, as you will have only sec­onds for positioning of parts. Be sure to trial fit parts
together before gluing. Also, never use watery THIN type
CA glue for gluing plywood and hardwood parts. Thin CA's
do not adequately bond these areas.

CAUTION

Some people may experience an allergic reaction when
exposed to fumes from CA glue or epoxy. As with paints,
thinners, and solvents, it is always important to use glues
only where there is adequate ventilation to carry fumes
away. A fan is recommended. Also, special care must be
taken when using CA, as it will bond skin as well as other
surfaces. Before using any CA, carefully read all label pre­cautions. When using CA, protective eye-wear and care in
keeping the glue away from the face is highly recommend­ed. If CA does happen to get into the eye, hold lid open
and flush with water only. Seek immediate medical atten­tion.

Notice:

Before starting be sure all parts have

not been damaged during shipping.

Once assembly has been started, all

warranty on parts are void.

ITEMS NEEDED TO COMPLETE THIS AIRCRAFT

 1 RADIO GUIDANCE SYSTEM (4 CHANNEL

MINIMUM REQUIRED, 5 STANDARD SER­VOS )

 2 6” EXTENSIONS
 1 Y-HARNESS

 1 ENGINE .61 2-CYCLE
 1 ULTRA SET CA ACCELERATOR

 1 ULTRA SET 2 OZ. BOTTLE MEDIUM CA

GLUE

 1 ULTRA SET 1/2 OZ. BOTTLE THIN CA

GLUE

 1 ULTRA SET 20 MIN EPOXY
 1

1/2” FOAM RUBBER

 1 SWITCH MOUNT
 1 3” SPINNER

3

COVERING

The Skylark 70 ARF is covered in a premium polyester
film chosen by many of the world's top flyers for its beauty,
toughness, and ease of application and repair. It is not
uncommon for ARF's to develop a few wrinkles in transit. If
this is true of your model, the situation is easily corrected.
Before you begin putting the pieces together, run over out
side edges of the covering with an iron. This is to make
sure that the surface of the edges are sealed and will not
move when heat is applied to the center of the covering.
Then go over the center of each section with the iron
(either specially designed for airplane use or the more
cumbersome household iron) or use a modeling heat gun.
Apply the heat (set at about 350° F), following along with a
soft cloth and pressing down on the covering as you go
around. This will more firmly set the covering adhesive into
the wood and keep your aircraft covering tight and smooth
in the future.

One of the great advantages of polyester film is that it can
be applied over itself without causing gas bubbles. This
allows you to repair your aircraft, as well as to customize it
in a number of ways. If, due to a flight mishap, you get a
hole or similar covering damage, simply trim away the
ragged edges and then apply a patch, following the direc­tions that come with your covering , which is available at
your hobby dealer.

RADIO EQUIPMENT & CARE

There are many fine radio systems on the market. Your
local hobby dealer and club members are good sources of
information on equipment and its suitability for various
projects. It is recommended that you speak to them before
making a final choice.

Today's RC systems are very well engineered and con­structed. However, they will remain only as good as the
way in which they are USED. Always follow the rules of
proper usage and all manufacturer's instructions for your
particular piece of equipment.

TRANSMITTERS: Keep your transmitter clean and free
from fuel residue and dirt. Battery condition and RF output
should be monitored, and the system should be aligned
and tuned annually. Do not transport under vibration (such
as on the floor of a car) without cushioning.

RECEIVERS: Receivers must be vibration free. When
installing in the aircraft, wrap them in a minimum of ¼" soft
foam rubber (not plastic foam). Keep well clear of all
cables and batteries. Tune annually (or as recommended
by the manufacturer), as indicated below under "Check­Ups."

SERVOS: Servos are vibration prone. Be sure to mount
them with grommet shock mounts in servo trays which are
also shock mounted. Also be sure to keep them clean. If
the neutral position "drifts," this is a sign of change which
should not be ignored; find out WHY before flying again.

BATTERIES: Nicads also can suffer from vibration, so they
too should be wrapped in soft foam rubber before installing.
Check their condition periodically by measuring the voltage
with a volt meter or battery tester. Charge the batteries
before EVERY flying session. When not used for a period
of time (such as during the winter months) the batteries
should be charged every 30 days. Never store batteries in
a discharged condition.

PUSHRODS: Obviously, pushrods should be installed to
operate freely, so that they place no load on the servo.
Using a servo's power to move a tight rod or heavy surface
by force increases the battery drain, shortens the electron­ic life, and can cause neutralizing problems. In addition, it
is important the pushrods do not flex or vibrate. Any vibra­tion is transferred directly to the servo, and its gear, motor,
and pot. To avoid flexing and vibration, use guides and fair­leads on the rods.

CONNECTORS: In using connectors, never pull on the
wires to disconnect; grasp the plugs instead. Clean them
by dunking in a solvent, such as dope thinner. Tape the
connectors together when installing and make sure there is
no strain on the cables.

CHECK-UPS: A full check-up by the factory or an author­ized service center should be done AT LEAST ONCE A
YEAR, as well as any time something unusual occurs dur­ing usage. A malfunction or "glitch" is the first sign of an
impending failure; it should not be ignored. The checkup
should include tuning and alignment of the system, as well
as battery testing.

Important

Information

Covering coming loose is not
COVERED UNDER WARRANTY. Due to tem­perature changes the plane may develop
some wrinkles in the covering that you will
need to remove with an iron. Be sure to seal
the edges down first so that you do not
cause the covering to shrink and leave
exposed areas of wood. Please inspect the
plane before beginning to assemble to make
sure you are happy with it. After assembly
has begun you cannot return the kit. If you
find a problem before beginning to assemble
the plane you must contact us, please do
not return it to the dealer.

Caution:

Before starting, care-

fully go over all high

stress areas with an

epoxy or wood glue to

confirm all areas are

well glued.

4

WING ASSEMBLY & INSTALLATION

AILERON INSTALLATION

1.  Collect the following parts:

(1) Left wing
(1) Right wing
(1) Left aileron
(1) Right aileron
(8) CA hinge

1.  Locate the pre-cut aileron hinge slots in both

wing halves. Using a hobby knife (#11 blade),
slide the blade into each slot to make sure it is
cleanly cut.

 Repeat this process with the ailerons, making

sure all hinge slots are clean.

2.  Place a straight pin into the center of each of

the four CA hinges.

 Slide each hinge into the hinge slots on one of

the wing halves. The pin will prevent the
hinges from going in further than halfway into
the wing.

3.  Select the aileron for the wing on which you

are working and insert the exposed half of
each hinge into the aileron slots.

 Slide the aileron toward the wing until no gap

remains between the aileron and the wing.

4.

 Carefully check the alignment of the aileron.

There should be about 1/32" on both ends.

 When satisfied with the alignment, remove the

straight pins, being sure to keep the aileron
tight to the wing. You may wish to apply a few
pieces of masking tape to keep the pieces in
place.

5.  Keeping the aileron and wing in position,

apply 3 or 4 drops of Ultra Set thin CA to the
small exposed area of each hinge.

 Turn the assembly over and again apply 3 or

4 drops of Ultra Set thin CA to the exposed
hinge surfaces.

 Allow to dry for 10 minutes before flexing the

aileron.

6.  Repeat the above steps for the other half of

AILERON SERVO INSTALLATION

The following pictures may not exactly match the hard­ware you are using. Always check the radio manufac­turer's instructions when installing radio equipment.

1.  Collect the following items:

(1) Wing
(2) Servos with rubber grommets installed
(8) Servo Mounting Screw (supplied with radio)
(2) servo extensions 6” long

2.  Locate the string used to pull the wires

through the wing.

5

3.  Plug the

servo extension wire into the servo .

 Gently pull the string out of the aileron servo

hole and tie it or tape it to the servo wire.

 From the top of the wing remove the covering

over the hole that is next to the center rib.

 Pull the servo wire towards the center of the

wing using the string inside the wing.

 When the servo plug exits the wing then tape

the plug to the top of the wing.

4.  Slide the servo into the servo hole in the wing

with the out put arm towards the aileron.

 Using the screws that come with your radio,

mount the servo into the wing.

 Repeat these steps for the other half of the

wing, so that both servo extensions are exiting
the holes in the center of the wing and the ser­vos are installed in the wing.

Aileron

AILERON CONTROL HORN INSTALLATION

1.  Collect the following items

(2) Large control horn with back plate
(4) 3/4" screw
(2) Metal metal clevis
(2) 10” threaded rod
(2) Swivel keepers

2.  With the aileron servo arm in place, make a

mark at a 90º degree angle to the trailing edge
and in line with the servo arm.

1.5mm x 20mm
MACHINE SCREWS

METAL CLEVIS

CONTROL
HORN

PLACE CONTROL HORN AT HINGE LINE

Bottom of wing

Wing is upside
down in this view

3.  Position the control horn so that the clevis

holes are right next to the hinge line, as
shown.

4.

 Using a 3/32" drill bit, make a hole in each

screw location.

 Mount the control horn with the 1.5mm x

20mm machine screws.

5.  Thread the 10" rod onto the metal clevis.

Make sure the rod shows in the center of the
metal clevis.

 Place the metal clevis in the top hole on the

control horn.

6

6.  Make sure the aileron is in neutral (level) posi-

tion, mark where the wire meets the hole on
the servo arm.

 Remove the wire and cut it about 1/2" beyond

the mark.

Mark wire

7.  Bend the wire 90 degrees up at the mark you

just made.

 Slide the swivel keeper over the wire and clip

onto the pushrod.

 Slide the silicone keeper over the clevis.

Repeat these steps for the other aileron servo.

MAIN GEAR & WHEEL INSTALLATION

1.  Collect the following items:

(2) Landing gear wire
(8) 2 x 5/16"screw
(4) Landing gear strap
(3) 2-1/2" wheel
(4) Wheel collar
(4) Allen head set screw

2.  Locate the landing gear slots in the bottom of

the wing and remove the covering material.

 Insert the shorter end of the gear into the hole

in the bottom of the slot, so that it points
toward the center of the wing.

3.

 Use two Metal straps and four screws on each

side to secure the wire gear.

4.  Install the wheels on the axles, as shown.

First the wheel collar goes on, followed by the
wheel, then the second wheel collar, and the
set screw. Tighten the set screw.

AXLE

WHEEL

SET SCREW

WHEEL COLLAR

WHEEL COLLAR

PUSH ROD INSTALLATION

1.  Collect the following parts

(2) 19-3/4” Wood dowels
(2) 1.5mm x 15cm wire
(2) 1.5mm x 20cm threaded wire
(2) Metal clevis
(4) shrink tubing

RUDDER ELEVATOR PUSHROD

2.  Remove the metal clevis from the end of a 1.5

x 20cm wire.

Fuselage