.
Modelers were also amazed at how fast and easy it was to build. A couple of weeks
of spare time was sufficient for most builders. We've heard from people who can
frame one up in twelve, ten, even six hours. Another group of modelers actually built
and flew a Four-Star 40 in a day! The design has become so popular in some clubs
that it's practically the official "club plane".
It became fairly obvious that the Four-Star 40 was like a good movie it deserved a
sequel. The reason that it was enlarged to a 1.20-sized airplane was simple - that's
what we wanted for ourselves, so that's what we built! Besides, large sport models
have become very popular the last few years and SIG needed an airplane that could
introduce sport modelers to the world of "big birds". With its 81" wing span, the Four-
Star 120 is big enough to qualify for I.M.A.A. fly-ins, but is still fairly easy to transport.
The Four-Star 120 isn't a simple blow-up of the "40"-size. Some elements of aircraft design don't conform well to enlargement.
For instance, the engines for this design are proportionally heavier than those for the smaller Four-Star, which meant a shorter
nose moment was necessary for the "120". In effect, the "120" is an entirely new design, but it still incorporates the aerodynamic
and structural features that made the Four-Star 40 such a success. What are they? There's no secret to it, really - the simple
answer is "lightness and wing area".
The two main goals driving the design of the Four-Star 120 were the same as for the
"40". First, it had to have outstanding flight performance which includes smooth
aerobatic capabilities and solid slow-speed handling characteristics. You won't
believe how this airplane goes from a rip-snortin' aerobatic dynamo in the sky to a
smooth-as-silk floater in the landing pattern! Second, it had to be very easy to build,
allowing the modeler to whip through construction without a bunch of sanding and
shaping. Several prototypes were built and flown to make sure the design lived up to
the goals just described. We believe the final design presented in this kit represents
the finest blend of building and flying characteristics to be found in a sport model of
this size.
Personally, I've had more fun with the Four-Star 120 than any model I can remember. There's no doubt in my mind that you'll
enjoy it just as much!
Engines, Propellers, and Mufflers
There is a tremendous variety of engines available in the size range specified for the
Four-Star 120. A good 1.20-size 4-stroke will TRULY fly this airplane well - that'swhat
it was designed for! However, 2-stroke and 4-stroke engines work equally well in this
model, so choose your favorite type, keeping in mind the type of performance that you
wish the model to have. If you want maximum aerobatic capability and vertical
performance, use an engine towards the upper end of the recommended size range.
Engines at the bottom of the range will still allow for exciting flights with slightly
reduced vertical performance. Remember, this is an airplane that likes to fly through
aerobatic maneuvers with its wing rather than by the brute force of its engine.
RECOMMENDED
ENGINE RANGE
.90 - 1.20 2-Stroke
- 1.20 - 1.60 4-Stroke
Use only those propellers recommended in the instructions supplied with your engine.
If you use a very high-powered engine in your model, we recommend using a prop
with a relatively large diameter and low pitch. This will give you loads of pulling power
during maneuvers without a lot of excess speed. An 18" diameter propeller is about as
big as you can use on this model and still have adequate ground clearance. Paint the
tips of your propeller with a bright-colored paint so that you can easily see the prop arc
when the engine is running. Be sure to balance your propellers to keep vibration to a
minimum.
Use a muffler! A loud engine may cost you (and possibly your club) the use of your flying field if it annoys a non-flying neighbor.
Use the muffler that came with your engine or one of the many after-market mufflers that are available.
Radio Requirements
A four-channel radio system is required for the Four-Star 120 to operate the ailerons, elevator, throttle, and rudder. Each aileron
uses its own servo, so you'll need a total of five servos. For positive control (and peace-of-mind) we recommend using heavy-
duty servos with at least 55 oz.lin. of torque for all of the flight controls.
Содержание Four-Star 120
Страница 29: ... ...