Top Flite TOPA0310 - Manual (Page 5)

model SR-10. The most recognizable features of the aircraft
are the gull wing and the 18 blisters on the engine cowl for
the engine valve assemblies.
The gull wing at first looks difficult to build, but, it is actually
comparatively easy to build using the die-cut trailing edge
jigs. The most difficult part of the wing construction is the
extensive cap stripping needed to duplicate the fabric
covered appearance of the full-size aircraft. There are 132
feet of cap stripping material included in this kit, but you
won’t need all if it. You should end up with at least two feet
of scrap!
With its eighteen blisters, the cowl looks, and is,
intimidating! We like to call it our easy-to-build
20-piece cowl. It sure does look nice on the model though. If
you aren’t up to it, leave the blisters off and tell everyone
your model is the SR-10-2. The plans show where to modify
the top fuselage formers to the outline of the SR-10.
Speaking of the fuselage, it’s pretty much your typical stick-
built structure. We have worked hard to engineer a structure
that is easier to build than most stick type structures and to
assure a straight, square structure. We have even die-cut
some of the sticks where precision is required (die-cut
sticks; now that’s unique). As the full-scale aircraft is very
big, so is this 1/5 scale model. Its very size makes it easier
to incorporate some impressive scale details. To gain access
to the wing hold-in bolts you must build at least one
functional door. Once you build one, the second won’t take
nearly as long.
Just keep one thing in mind as you build this model: “You
never finish a scale model; you eventually come to a point
where you stop working on it and fly.” While this is a
moderately difficult project, it is also richly rewarding.
SCALE ACCURACY
The Top Flite Stinson Reliant SR-9 is a faithful reproduction
of the full-size aircraft, with a few exceptions:
1. The horizontal stab/elevator area has been increased by 9%
to improve pitch stability. To make the stab closer to scale,
move the stab leading edge 1/2" aft. Then re-contour the
ribs and stab tip.
2. The wing strut attaches directly to the side of the fuselage
to simplify construction. This is close to the location of the
SR-10 but is noticeably different than the SR-9. If desired,
you could move the mounting location to the scale
location.
3. The windscreen shown is for the SR-9. With some balsa
blocks you could make one that looks like the SR-10. This
is one area where your craftsmanship will allow you to
make the windscreen as scale-like as you desire.
This is one model that can be made very true
to scale.
POWER
DO NOT overpower this model. The power plant needed for
your model will largely depend on how you finish it and
whether you use a gas or glow engine. If you cover the model
with fabric and then paint it, you could easily add four or
more pounds to the finished weight of the model. A gas
engine will also add a pound or two. This model can easily
handle the weight, however, as it has a large wing area and
high-lift airfoil.
The weight of the model does affect the power required to fly
it, however. If you are careful to build the model as light as
possible and cover if with film instead of fabric, the flying
weight will be closer to 16 lbs. At this weight a strong 1.20-
size four-stroke engine will be ample power. But if you build
heavy and cover the model with fabric and paint, the model
will weigh closer to 25 lbs., requiring a more powerful engine.
Our prototype model was covered with Super Coverite Fabric
and then painted with the Stits paint system. It was detailed
with pinking tape, rib stitching and other detailing. It had a
flying weight of 23 lbs. and was powered by an O.S. FT-160
twin-cylinder engine. This proved to be a near perfect
combination. The engine produced a static thrust of 13 lbs.,
8 oz. with a Zinger 18 x 6-10 prop. A strong 1.20-size engine,
such as the O.S. FS-120 III or the YS-120 NC, will produce a
static thrust of 13 lbs. on a 16 x 6-10 prop. This would be
ample thrust for a model that weighs less than 20 lbs.
You should also bare in mind that this is a high-drag aircraft.
Weight is not the only factor you need to consider when
selecting an engine. Normally, a 1.20-size engine would be
adequate power for a 16 lb. model - and is for the Stinson as
well. But, due to the higher drag of the Stinson, a tired 1.20 size
engine will not give the performance you would expect during
slow speed maneuvers, such as a go-around during a landing.
That is why we recommend only powerful 1.20 engines.
It is important that you do not overpower this model as well.
This is a fabric-covered aircraft which means the tail surfaces
and wings will not have the rigidity you are used to with other
models. Too much power will result in higher airspeeds, which
could cause flutter. While a 35cc gas engine is within the
recommended power range, a high performance, powerful 3W
type of engine should not be used. Our 23 lb prototype model
flew in a convincing, scale like manner on an OS FT-160
engine producing 13 lbs., 8 oz of thrust.
If you do install an engine at the upper end of the power
range, you should sheet the tail surfaces with 1/16" balsa to
increase their rigidity.
If you cover the model with fabric and paint, be careful not to
allow excess weight to accumulate by applying too much
filler and paint. This is a large model and paint can quickly
increase its weight if not properly applied.
WHAT’S INCLUDED IN THE KIT
This is a very complete kit for a model of its size and type.
However, there are a few items that are not included. We
have not included an engine mount and mounting hardware
because of the wide variety and type of engines that could
be used on this model. We do not feel it fair to increase the
cost of the kit by including a mount that most modelers
won’t use anyway. Similarly, we have not included control
surface hinges or the rudder pull-pull linkage system. It has
been our experience that many modelers building this type
of kit are likely to have strong preferences for these
components. (If you have no preference, we recommend
Robart #310 Super Hinge Points (24 total) (2-ROBQ2510) and
the Sullivan No. 520 steel Pull-Pull Cable Kit.)
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