Great Planes PT-E Trainer Electric Kit - GPMA0110 - Manual (Page 30)

D 25 Working on a flat table, place the two wing panels
together at the center Block up both wing tips 3-1/2"
with stacks of books, then trial fit the die-cut 1/8"
ply dihedral braces at the center Enlarge the open-
ing in W-l and the bottom sheeting if necessary to
allow the dihedral braces to fit without forcing them
in.
PRACTICE THE NEXT STEP "DRY" BEFORE
ACTUALLY DOING IT!
D 26 Place waxed paper under the wing center joint,
then mix up a batch of epoxy (30-minute epoxy is
preferred here to give you more time), and apply it
to the dihedral braces and spars Slide the wing
panels together, clamp the dihedral braces to the
spars with clothespins, and wipe up the excess glue
with a tissue While you are waiting for the epoxy
to harden, apply thin CA along the joint where the
two W-l ribs come together Make sure the wing
panels remain undisturbed until the epoxy has
fully hardened.
D 27. After the epoxy has hardened, examine the center
joint and fill any gaps with balsa dust and CA glue.
D 28. Sand the center section and the entire wing
smooth with your T- bar sander NOTE: When sand-
ing the wing, you must be very careful not to change
the shape of the wing by accidentally sanding into
the wing ribs.
D 29 Find the two 1/32" x 1-1/4" x 1/2" plywood pieces
These are the wing plates which protect the trailing
edge from damage by the wing hold-down rubber
bands.
D 30 Working on the table edge, use a sanding block
to "feather" (taper) the edges of the wing plates
Feather three edges of each plate, leaving one long
edge square.
D 31 Make marks on the T E 1-inch each way from
the wing centerline
D 32 Put the wing plates in position on the T E The
edge of the plate that is not feathered goes to the
rear along the T E The 1-inch marks you made in
step 31 are where the plates begin
D 33 Apply thin CA glue around the edges, holding
the plates firmly in place until the glue sets.
D 34. DO NOT OMIT THIS STEP! Accurately weigh
the wing on a postage scale It should have a total
weight of no more than 5 ounces. If it is heavier
than 5 ounces, there is not much you can do other
than some light sanding of the leading and trailing
edges and the wing tips Do not sand the hardwood
spars, as this could weaken the wing Proceed to the
next section.
PREDICTING THE FINISHED FLY-
ING WEIGHT
At this time you should try to accurately predict
what the final weight of your PT-Electnc will be Re-
member that you are shooting for a target weight of 48
ounces or less with a 6-cell 1200 mAh motor battery, and
50 ounces or less with a 7- cell 1200 mAh motor battery
If it looks like your airplane will be only 1 ounce over-
weight, don't worry about it, as you will probably be satis-
fied with the flight performance If, however, you predict
a final weight that will be 3 ounces or more overweight,
you should take another look at the components you will
be installing in your airplane (servos, battery, wheels), to
see where you can reduce weight. I'll talk more about this
later
Here is a sample weight computation:
Fuselage, etc (see p 26 step 11) 7.0 oz.
Wing 5.0
Wire landing gear and all hardware 2 0
6 #63 rubber bands 0.25
Wheels (lightweight) 1.5
Thrustmaster motor, harness, prop
and spinner 9.5
Receiver, switch, 3 standard servos, 225 mAh
receivel bdtteiy 8.75
6-cell 1200 mAh motor battery 11.5
Covering material 3 0
TOTAL 48.5 oz.
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