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Design Philosophy
When developing the Four-Star 40, two design considerations were at the top of
the list in importance:
Impeccable Flight Performance
- Like all Sig kits, it had to have
smooth, reliable flight performance with no surprises. It had to fly through
maneuvers, not just be pulled through by brute force of the engine.
Gentle slow speed and stall characteristics were equally important.
Easy Construction
- Most modelers want to get in the air quickly, and
who can blame them? Low parts count and minimal sanding/shaping
were deemed necessary to help reduce building time and effort. It also
had to be easy to cover with iron-on coverings with little painting required.
The following paragraphs are meant to give you a bit of insight on the aircraft's design by discussing individual parts and
the thought process behind them. Several prototypes have been built and flown to test the ideas and we believe the final
design presented in this kit represents the finest blend of building and flying characteristics from those tests.
Fuselage Construction
- Lite-Ply fuselage construction has become very popular in the last few years and with good
reason. It's fast, strong, and lightweight (with proper attention to lightening holes, etc.). The plywood fuselage doubler sets
the thrust line, reinforces the wing saddle, and provides locations for the tank floor and wing hold-down blocks. A
shapeless box doesn't look good, so three stringers and a slightly curved top deck were added to give it some shape
without adding much work. A plastic cowl would have looked nice, but would have added complexity and weight, as well
as required painting, so simple "cheeks" were used instead.
Canopy
- A nicely rounded canopy adds even more shape to the airplane, and it's already made for you! It doesn't require
painting because the frame is highlighted with striping tape. Setting the canopy relatively far back on the fuselage gives
the model an aerobatic/fighterish look.
Landing Gear
- Aluminum landing gear is durable and easy to install. Mounting it on the fuselage instead of the wing
simplifies wing construction and lowers the parts count. The tailwheel is a bit unique in that it's attached directly to the
rudder without the usual plastic tailwheel bearing. We've tested this installation quite extensively without any problems.
The amazing strength of EASY HINGES and cyanoacrylate adhesive make this simple, effective tailwheel installation
possible.
Tail Surfaces
- What could be easier than totally pre-cut tail surfaces that come
out of the box ready to sand? There's a small weight penalty over built-up
surfaces, but the time saved during construction is worth it.
Wing Construction
- No leading edge sheeting saves considerable building
time. The strength of the wing is derived primarily from the spruce main spars
and shear webbing. The leading edge uses a large radius for superior slow
speed handling and stall resistance. The flat wingtips are actually very efficient
and don't require carving and sanding like rounded tips made from balsa blocks.
Airfoil
- The airfoil is nearly symmetrical for great aerobatic performance, but is
flat aft of the bottom main spar so it can be built flat on the table.
Ailerons
- Like the tail surfaces, the ailerons are pre-cut from sheet balsa. The taper gives the illusion of a tapered wing,
but it is also good from the standpoint of flutter resistance. Many designs taper just the outer few inches of each aileron at
the tip, because that's where flutter usually first develops. On this design, the taper simply extends the full length of the
aileron. The aileron torque rods have been specially bent to provide a small amount of differential movement which
improves the roll characteristics.
Glues
There are many different glues available today for model construction that it can be confusing to even the experienced
modeler. To simplify matters, most glues can be classified as one of four basic types:
1. Fast cyanoacrylate adhesives (abbreviated in this book as "CA") such as SIG CA, Hot Stuff, Jet, etc ...
2. Easy-to-use water-based glues such as SIG-BOND (yellow) and SIG SUPER-WELD (white).
3. Super strong (heavier) two-part epoxy glues such as SIG KWIK-SET (5-min cure) and SIG EPOXY (3-hour cure).
4. Traditional solvent-based model cements such as SIG-MENT.
Summary of Contents for Four-Star 40 SIGRC44
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