General Notes Assembling Plastic Parts

General Notes
The Customaire is a challenging kit designed for experienced modelers. Basic parts must be accurately built in order to produce
a strong, well aligned model. If you haven't already completed a number of rubber powered kits successfully, we suggest that
you set your Customaire aside until you have gained some experience on several of the simpler Sig kits.
Even if you are an experienced builder, please read the instructions before beginning construction. A few minutes spent reading
Assembling Plastic Parts
Small scissors are the best tool for cutting out plastic parts. While cutting, hold parts so that the trim line can be seen clearly.
Double check with the instructions to BE SURE YOU ARE CUTTING ON THE RIGHT LINE. The edges of the shells and the
back surface of the completed cowling assembly can be finished flat and accurate to the desired line by rubbing them across a
sandpaper block. Go slowly and carefully.
Cement plastic to plastic or to wood with a thin, even coat of Sigment. Other types of cements or solvent may work, but try on
test scraps first. Some cements soften plastic excessively, others will not adhere at all. Plastic joints dry slowly.Waif overnight
Most of the paints sold for plastic models are OK on these parts. But before using any kind of paint on your Customaire parts,
test it on scrap plastic.
Wheel Pants
Cement L-1 discs to the inside of pants and wheel shells.
Allow to dry completely. Pierce or drill the center holes. It's
handy to leave holes undersize, enlarging them when parts
are complete. This allows holes to be shifted slightly for
perfect alignment.
Trim shells from the plastic sheet, finishing them flat on a sandpaper block as
shown. Cut the wheel well openings in the pants roughly to shape and finish to
exact shape with sandpaper sticks. Make a flat sanding stick by cementing
sandpaper to a popsicle stick and a round one from a round pencil or small
Insert four small pins through the outer shells as illustrated.
These provide a firm stop for the inner shells to rest against.
Apply a thin, even coat of Sigment to the inside of the lip of
the outer shell and slide the mating inner shell in place.
Handles made of masking tape prevent gluey finger marks and make the parts
easier to work with.
When parts are completely dry, use a sandpaper block to smooth any sharp edges
of wheels and pants. Cement eyelets in wheels, shifting the holes if necessary to
prevent wobble.
Cowling Assembly
There is no trim line on the cowling and
dummy motor. Just cut from the sheet
leaving a small rim around the edge like
the brim of a hat. Carefully trim the round
center disc from the dummy motor.
Remove the small lip at the trim line,
leaving the center ring smooth and flat.
Apply cement to one surface of each N-2
and place one inside and one outside the
cowling, sandwiching the center ring of the
motor between them. Turn them cross
grained, matching the square cutouts with
each other and centering them in the
middle of the cowling. N-2s should stick to
the cowling AND TO EACH OTHER.
Cement two N-1s together, add stiffeners, and build up the 3/32"x3/16" spacing frame. Try the completed N-1 former inside the
cowling. It must fit smoothly without forcing. If necessary, sandpaper the edge of N-2 or build it up with a paper strip to make a
good fit. Then remove the former, apply cement to the edges and the front of the spacing frame, and fit it in place permanently.
When thoroughly dry, trim away the overhanging plastic, and sandpaper the back surface flat on a sandpaper block.
Match the hardness of the longerons for the right and left sides. MAKE SIDES ACCURATELY, giving special attention to the
nose and wing mounting areas.
Complete the following subassemblies before starting the fuselage box frame:
All former assemblies ("F" parts).
Bulkhead F-11 and three cross pieces "R".
Assembly of F-6 and the landing gear wire.
Cowling and dummy motor assembly.
Now invert the fuselage sides and pin them over the bottom view of the fuselage. Cement cross pieces "R" and the upper part
of F-11 in place in the cabin area. When dry, pull the bottom longerons together and finish cementing F-11. Cement cross
OPERATION. Now add F-2, 1, 6, 5, 9, and 10. Complete the main frame by drawing the fuselage sides together at the tail and
installing the remaining cross pieces.
When adding the 1/16" sq. stringers, note that the stringer J is bevelled to fit against the lower longeron at F-6. The rear ends of
K, L, M, and N are supported by a piece of 1/16" sq. cemented to cross piece "S".
Before attaching the cowling and motor, carefully position the completed cowling assembly on the front of F-1. F-1 should be
1/32" smaller than the cowl all around the edge to allow for the 1/32" sheet covering. If F-1 is too large, sand the edge where
required. If F-1 is too small, cement paper strip around the edge to build it up. When the 1/32" allowance is correct, remove the
cowling assembly and fit the sheet covering in place. Wherever the edges of the sheet butt together, cement a 3/32" sq. support
between F-1 and F-2. Sandpaper the front surface of F-1 flat with a sanding block and cement the cowling assembly in place.
Tail Surfaces
Build over the plans using the die cut and strip balsa parts called for. Cover both sides.
Landing Gear
Building the wheels and pants is described in "Assembly of Plastic Parts". Cement L-2s and L-3s together to make lower struts,
leaving the 1/32" groove for the landing gear wire. Round the edges. The lower struts are now used as forms for making the
upper shock struts.
Cut two 1-1/8" by 7" shock strut strips from typewriter paper. Also cut two 1-1/2" squares from wax paper. Wrap a lower strut in
wax paper, and then wrap a paper strip snugly around the outside, thoroughly cementing the layers of paper together as you
wrap. When cement has started to set up, the wax paper will allow the shock strut to be slipped off the form. Discard the wax
paper. When shock struts have dried completely, they can be cut and sanded almost like wood. Bevel the upper and lower
struts as shown in the drawings. BE SURE TO MAKE RIGHT AND LEFT HAND PAIRS OF STRUTS.
Now, by turning and sliding, the struts can be worked onto the wire landing gear legs, one piece at a time. Adjust to proper
length and position. Add wheels and pants to the axles. Cement lower struts to the pants and the wire. Cement upper strut only
to the lower strut. DO NOT CEMENT THE STRUTS TO THE FUSELAGE. Leave about a 1/16" gap to allow the landing gear to
Top Wing
Accurately assemble the center section consisting of leading and trailing edges, pieces marked "B", and W-1 ribs. Pin firmly to
plans. Do not add "F" pieces yet. Now build the outer panels, fitted against the center section, but not cemented to it. Cut
notches in "A" pieces before cementing in place. Note that W-5 is glued on top of T-1, and W-4 rests on top of a piece of 1/16"
sq. A pre-bent piece of 1/16" sq. is used to round out the leading edge on top of T-3.
Remove the three wing panels from the plans and bevel the ends of the center section to match the outer panels when they are
supported by the cardboard dihedral jigs. BE SURE THE DIHEDRAL JIGS ARE IN THE PROPER LOCATION, then cement the
leading and trailing edge joints. Carefully fit the four dihedral braces marked "D" and "E" in place. Pieces marked "F" are then
securely cemented above them in rib notches. All joints of D, E, and F should be coated with cement a second time.
Lower Wing
Lower wing panels are built in the usual way. Note that the tip ribs are made of 1/16" sq. scrap cemented on top of T-4 and
sanded to shape after panels are complete. The 3/32" sq. piece that forms the trailing edge cutout is tapered to blend into the
trailing edge in the same way.
Cement 1/16"x1/8" strips right on the Krome-Coat
patterns. When dry, cut from the sheet with a sharp
blade and round the edges slightly. Bevel the lower
ends as shown on the front view.
Nose Plug
Assemble nose plug from parts shown on the plans.
Round the front of the crankcase as shown. Cement
eyelets securely. If the hole for the propeller shaft ends
up at a slight angle, rotate the plug so the propeller will
point downward. Then mark the top of the block so you
will aways plug it in the same.
Cover all parts before
final assembly.
Windshield must be
added after the upper
wing is in place. Do not
shrink or dope the wing
or tail unless they are
pinned down on a flat
surface while drying.
Use Sig Lite-Coat
Dope only.
Final Assembly
Don't try to cement parts to the paper covering.
Wherever parts are to be joined, remove a small section
of paper to expose bare wood for a gluing surface.
Spot-cement tail surfaces lightly in place. DON'T
UNDER THE STABILIZER. Cement the top wing in
place on the fuselage. Check the correct location with
the plan and align.
Bevel the inner ends of the bottom wings slightly so they fit against the fuselage when they are held parallel with the top wings.
Support the fuselage upside down so its weight is not resting on the wing tips. Center the top tabs of the N struts in the slots in
the top wing and cement very lightly. (They may have to be moved later.)
Use two pieces of masking tape to hold the ends of the bottom
wings in place on the fuselage. Leading and trailing edges butt
against the ends of the cross pieces "S". Insert the bottom tabs
of the N struts into the slot between the double ribs in the
lower wings. The struts should fit against the ribs without
Struts can be moved forward or backward slightly in the slots,
or sprung a little for improved fit. If wings are well aligned and
struts still will not fit, the struts will have to be trimmed or made
is correct, cement, cement the strut ends lightly to wing ribs,
and the wings to the "S" pieces. Don't cement tabs in slots.
Tabs add no strength, but are useful in alignment and repair.
Now you are ready to fly your plane, and FLYING is what the Sig Classic models are designed for. Most models as realistic
looking as your Classic make poor flyers. They're often tricky to adjust and clumsy in the air. But Sig's Classic kits give you
three important features that assure you of successful flights:
1. A PROVEN flyable design.
2. A reliable way to make flight adjustments.
3. Complete flying instructions.
Read and follow these instructions carefully. They are the key to satisfying flying.
Testing And Adjusting
You have invested a lot of time and effort in building your model, don't waste it all now with careless testing. Most models fail to
fly because of poor adjustment, not poor craftsmanship. Be as careful in your testing as you were in your building.
Every model is a little different and needs its own special set of adjustments. Contest winning flyers make dozens, even
hundreds, of test flights "trimming" a model for best performance. So don't give up if your first flights aren't perfect.
Preflight Preparations
Before you leave the workshop for the flying field, take these important steps.
Looking from the front of the model, check that the bottom of the wing and tail
surfaces are flat - not twisted. Sight down the center line of the fuselage as shown
in the drawing. Right and left wing should look alike; you shouldn't see the top of
one wing and the bottom of the other. The fin should point straight ahead, and the
stabilizer should be flat. (This does not mean that the stabilizer and the wing sit on
the fuselage at the same angle. The wing will be tilted upward more than the tail).
A model can be made to fly with twisted surfaces, but it's confusing to adjust and if
the warps change from day to day, you can't detect it. The drawing shows how a
surface can be straightened by twisting it in the desired direction while holding it
under a heat lamp or other electric heater. Work with it until it is as flat as possible.
If your wing has struts, loosen them before bending and re-cement them afterward.
The correct "Balance Point" for your ship is shown on the plans. Mark this point on
the bottom surface of each wing. When supporting your plane on your finger tips at
these points, the fuselage should hang level. See the drawing. Add weight to the
nose or tail until it DOES hang level. Don't be afraid to add the necessary weight.
Modeling clay makes handy balancing weight - it can be pressed permanently in
any corner. Wire solder or BB shot can be used by cementing in place.
If one blade of your propeller always swings to the bottom, a tiny smear of clay on the other tip will improve the prop's balance
and reduce vibration.
Power-Off Tests
A rubber-powered model is adjusted
in two steps. First, the tail surfaces are
adjusted to produce a good glide.
Then the propeller assembly is
adjusted to give a smooth, powered
flight. Wait for a calm day.
Begin by gliding the model from your hand into a patch of tall grass. Grasp the ship by the fuselage near the balance point, and
aim the nose at a spot on the ground about twenty feet in front of you. Launch the ship forward about the way you would a
paper dart airplane, nose down.
Your goal is a steady glide to the ground, moving at a CONSTANT SPEED, and travelling straight ahead or turning gently. You
will find the trick is to launch the model at its natural speed and glide angle. If the glide is poor, it can mean that the ship needs
adjustment or that you need more launching practice. So try several launches before deciding on adjustment changes. When
your ship acts the same way on each launch, you can be pretty sure that you are seeing its true characteristics, and not just a
poor launch.
If your plane noses up, LOSES SPEED, and then falls clumsily or dives,
that is a STALL. To cure a stall, adjust the angle of the stabilizer by
changing the thickness of the incidence block under it. Lower the front
edge or raise the rear edge. See drawing. But make SMALL changes 1/32" at a time. If a change of more than 1/16" is needed, go back and
perform the Preflight checks again. It's likely your Classic is incorrectly
balanced (tail-heavy) or the surfaces are warped.
A model that darts quickly into the ground without swooping or stalling,
is diving. The dive can be cured by adjusting the stabilizer in the
direction shown in figure 5 (in 1/32" steps). Here again, don't change the
height of the incidence block more than 1/16" without first re-checking
the Pre-flight steps. Warps or nose-heaviness may be causing the dive.
A plane that glides in a straight line takes a lot of flying space and a lot
of chasing, so it's best to adjust the glide for a slight turn. The plans for
your model will tell which direction.
The size and direction of the glide circle can be controlled by adjusting
the fin. The drawing shows adjustment for a right turn. Moving the fin
opposite, of course, gives left turn.
Small changes in fin setting can be made by bending the surface. But if more than 1/32" or so of change is required, cut the fin
loose and re-cement it at the desired angle. When the glide is smooth and steady, you are ready to go on to powered tests.
Power-On Flight
NOSEBLOCK IN THE DIRECTION YOU WANT THE PLANE TO GO. This kind of adjustment affects only the powered flight,
and will not upset the glide pattern you have developed.
Now - wind the propeller l-50 turns and launch your Classic into the wind
with the same motion you used in glide testing. The model should cruise
steadily forward, turning in the desired direction, and gaining or loosing
altitude gently.
If your ship tries to climb, but loses speed and stalls, point the propeller
downward by slipping a scrap of 1/32" balsa or a paper book match
between the top of the noseblock and the front of the fuselage. The wedge
is called a "shim" and the adjustment is called "downthrust". Downthrust is
illustrated in the drawing.
It's not likely that your plane will dive on first power flights, but if it should, put the shim at the bottom of the noseblock, tipping
the propeller upward (upthrust).
Downthrust is the "magic adjustment" that can make experts out of beginners. Learning to use it is the most important part of
your test program.
Increase or decrease the amount of downthrust (by changing the thickness of the shim behind the noseblock) until power flights
are smooth and free of stalling with 150 winds in the motor. Don't wind the motor any tighter until the lower-powered flights are
under control.
Power-On Turns
Because of the effects of the rotating propeller, models usually turn
better in one direction than the other. Your plans will say which way to
Don't circle any tighter than necessary. Circles smaller than about 50 ft.
diameter are tricky. If you have plenty of flying space, turns can be as
large as you like.
The drawing shows how side thrust is used to control power-on turning.
Making small changes, 1/32 at a time, adjust downthrust and sidethrust
together to produce smooth flights on 150 winds.
You may notice that turning to the right tends to hold the nose downright thrust acting a little like downthrust. If your plane begins to circle so
sharply that it loses altitude in a steep bank, reduce the amount of
sidethrust until the turn opens up to a safer size.
Longer, Higher Flights
When your Classic is flying smoothly with 150 turns in the motor, wind to 175 and try it. Make any necessary noseblock
adjustments, and then wind to 200, and so on. The safe number of turns that your motor will stand is shown below.
Rubber Motor Winding Chart
Length of Loop 1/4"
Hand Wound
180 200 220 235 250 270 290
Safe Number of Turns
Stretch Wound 440 485 525 570 615 660 700
A plane's weight determines how much power it needs. If your ship is huskier than average, it may not climb, even when fully
wound. In that case, add one strand (not a complete loop) of 1/8" Sig rubber to the motor. Tie an eye (like a slip knot) in each
end. This will provide the extra horse power needed for higher climb.
Whenever you add rubber, re-balance your model as outlined in the pre-flight instructions. Additional rubber tends to make a
plane tail heavy.
When your Classic has been adjusted according to instructions, it should have no trouble taking off by itself from a smooth
surface. No adjustment changes should be necessary. You may find that take-offs are better if you release the ship pointed at a
slight angle to the wind instead of headed straight into it. Experiment to find the best system.
Rubber Motor Hints
The rubber motor in your Classic kit will safely give you a whole season of flying if you stick to the chart. "Hand Wound" means
winding the propeller with your finger while the rubber is inside of the fuselage. "Stretch winding" is a more complicated twoman operation, but gives longer flights.
Before a motor can be safely stretch wound, it must be lubricated. Rub a few drops of Sig Rubber lubricant into the rubber
(AFTER the knot has been securely tied). Use just enough to make the motor barely damp. If it's too juicy, it will splatter all over
the inside of the fuselage. Next, make a strong wire hook, like a teacup hook, and lock it VERY TIGHTLY in the chuck of a hand
Then, while your helper holds the model by the rear rubber peg and the
cowling, stretch the motor out the front of the model to about twice its
normal length, unhook the propeller, hook up the winder, and wind while
slowly walking back toward the plane.
All the models in Sig's Classic series have been carefully designed and
flight tested to assure flying ability. Hand wound, you can expect flights of
10 to 25 seconds and stretch wound, 20 to 50 seconds. Like model
builders, some of the designs have more ability than others, but all are
proven dependable flyers.
A Classic flying model is not a ready-to-fly toy. Your skill in building and
flying DOES make a difference. So whether your flights are short or long,
you can be proud of completing a job which was successful because of
your own effort and ability.
Good Flying!
SIG MFG. CO., INC. is totally committed to your success in both assembling and flying the Customaire. Should you encounter
any problem building this kit or discover any missing or damaged parts, please feel free to contact us by mail or telephone.
401-7 South Front Street
Montezuma, IA 50171-0520
SIG MODELER S ORDERLINE: (to order parts)
SIG MODELER S HOTLINE (for technical support)
© Copyright SIG Mfg. Co., Inc.
SIG MFG. CO., INC............Montezuma, Iowa 50171-0520
The craftsmanship, attention to detail and actions of the builder/flyer of this model airplane kit will ultimately determine the
airworthiness, flight performance and safety of the finished model. SIG MFG. CO's obligation shall be to replace those parts of
the kit proven to be defective or missing. The user shall determine the suitability of the product for his or her intended use and
shall assume all risk and liability in connection therewith.
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