Top Flite Wristcrat - Manual (Page 3)

with our prototype machines. Essentially, the flaps
themselves are nothing more than the hinging and
subsequent control led movement of the 1" trail ing edge
stock itself. As shown, the flap extends from the poly-
hedral break, inboard to the point shown on the plans,
next to the fuselage. You will need to pick yourself up
some Sullivan #507 cable and tube material (one
package is all that's needed) from your local hobby
shop. The rest of the items needed are either in the kit
itself as scrap and /or common household items.
The need to understand the drawings provided is essen-
tial — study them. The flaps are hinged from the bottom
and driven by cable through the top of the wing. At the
exit point for each of the cable housing tubes you will
need to replace the stock balsa cap strip with a wider
one (about 1/4" - 5/16" will do ) to anchor the tubing. Also,
each wing rib end must be trimmed 1/16" cap that is glued
in place instead of the trailing edge stock itself. Note
that we've also added 1/16 x 1/2" balsa sheet, top and bot-
tom, to each inboard wing panel, at the trailing edge for
strength and to facilitate covering The flap control
horns were made and mounted in the same manner as
was the rudder horn, and the connectors are also made
from a common paperclip, as was the rudder connector.
The flap system is driven by a single servo that is
mounted, as shown, in the wing's center section. This
servo protrudes down into the fuselage itself and is con-
nected to the receiver's "throttle" connection.
Therefore, on a typical Mode II transmitter, where
aileron (rudder) and elevator are on the right stick and
throttle is on the left, the positionable throttle stick
becomes your control over the flaps. Our prototypes
have been set-up so that "full throttle" (stick all the way
up) and full down trim is "neutral" f l a p — in other words,
no flap, up or down, what-so-ever. Therefore, by moving
the throttle stick downward, the flaps come down also,
to whatever desired location. Moving the stick back up
to "full throttle" moves the flaps back to neutral. The
flaps can also be "reflexed" or moved upward forgetting
quickly through "sink" or down air or for compensating
for high winds, by moving the throttle trim lever upward
to whatever desired position. On our Airtronics equip-
ment, we typically can achieve about 6 to 8 degrees of
reflex, which is more than sufficient to make our
Wristocrats really scoot!! Honestly, you can't begin to ap-
preciate what an incredibly useful tool this system is un-
til you've tried it.
As you can see, the flap servo, at least in our prototypes,
is mounted in the wing's center section, with the output
arm literally inside the structure. This means that the
two center ribs,W-1, must be cleared out, at this point, to
allow the servo to be mounted in place. The best time to
do this is after the two inboard wing panels have been
glued together and before the top, rear center section
sheeting is installed. In fact, it is at this point that the en-
tire system is installed, tubing, cables, etc... Note that
the drive system in the wing's center section is essen-
tially a "blind mount". This means that all of the connec-
tions inside of the center section must be fitted to the
servo's output arm before covering it up with the top
sheeting. Afterfitting and making sure that the servo, by
radio command, does indeed actuate the cables in the
correct direction, with no binding, and that the geometry
is correct, then and only then can the servo be removed
from the wing and construction proceed. Later, after
covering, the servo is carefully installed, screwed in
place and the last connections are made to the flaps
themselves.
There are no guarantees that your particular radio
system will work this option and you therefore need to
determine this for yourself by first making sure that the
shape and dimensions of the servo you plan to use will
indeed fit as shown. Then you need to find out if your
radio system has the capability of offering you "reflex"
flap off of the throttle trim lever (some systems don't).
Our opinion is that even if you can't get flap reflex, due to
the type of radio you have, the flap option itself is still
worth the extra bit of work.
With the proceeding information still fresh in your mind,
we'll now move to the wing construction sequence of
this manual. The following assumes that you are
building the stock, non-flapped wing.
WING CONSTRUCTION
Be sure and protect your plans by covering them with
backing from a roll of Monokote™ or a material such as
clear food wrapping. Take a minute to study the plans
and understand them. We suggest building a right and
left wing panel, starting with the inboard sections first
and then joining these two completed structures at the
appropriate time in the building sequence. We'll start
with the left wing first. If you're planning on the flapped
version, it is at this point that you'll start adding the
structures shown (dashed lines) on the plans.
D 1. From the 1/16"x 3" x 30" sheeting provided in your kit,
cut, fit and locate over the plans, the bottom
leading edge sheet (use a long straight edge to
develop the correct width and to true-up the
edges). From the 1/8" x 1/16" spruce spar stock provid-
ed, measure and cut the required 15" length for the
bottom spar, set this aside for a moment. Now cut
and locate over the plans, the
1
1/4" x 1" length of
shaped trailing edge stock. Now cut and glue the
bottom center section sheeting in place tothetrail-
ing edge stock and the forward bottom wing sheet.
Cut, fit and glue in place the six bottom 1/16" x 3/16"
cap strips from the stock provided. Using one of
the die-cut W-2 wing ribs as a location guide, the
bottom spruce spar (cut earlier) can now be glued
in place. Lastly, note in the cross sections that the
leading edge of the bottom wing sheeting needs to
be lifted up and supported in order to match the
bottom contours of the wing ribs, forward of the
spar. This is best done with a length of trailing edge
stock.
D 2. Note that we've provided you with "tick" marks
just infrontof and just behindthewing paneldraw-
ings. These correspond with the rib locations. Use
a straight edge and a soft lead pencil to now mark
the rib locations directly on the leading edge and
center section sheeting. The first wing rib to be in-
stalled is the first W-2 rib, inboard from the poly-
hedral break (the inboard end of polyhedral brace
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