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108.
Don’t try and fudge the measurement and think you’ll get away with it!
109.
Once
you
have
accurately
determined the amount of lead needed for
correct balance, drill the holes in the foam
to accommodate it. Drill from the bottom
surface and stop before penetrating through
to the filament tape on the top surface of
the wing. You can then fill these holes with
the lead shaped into cylindrical pieces eg.
fishing sinker hammered into shape or a
piece of the lead flashing rolled into a
cylinder. Secure and conceal the nose
weight by covering with a patch of cross-
weave filament tape and coloured covering
tape.
110.
Having the balance point further forward (a few millimeters) has a greater stabilizing
effect ie. it will tend to hold onto a level flight path stronger and/or return to a level flight
path quicker. This is in fact desirable for less experienced flyers, and in these situations a
balance point as far forward as 135mm (5 5/16”) could be considered. The trade-off with a
balance point further forward than it needs to be is that more up trim is required for level
flight, adding to the glider’s drag (reducing maximum flight speed) and reducing the
maximum amount of lift the wing can generate before stalling. The glider also becomes less
responsive to control inputs (less aerobatic and maneuverable), doesn’t retain as much speed
in its turns and doesn’t fly as well upside down.
111.
The third most common cause of a poorly performing glider is incorrect control
surface movement. Too much movement and the glider will become hard to control, easier
to stall and generally not very fun to fly. Too little movement and the glider will become
unresponsive and also not very fun to fly. The correct amount of elevon and elevator
movement for the Booby is determined by its balance point (a more forward balance point
requires more control movement), the pilot’s skill level (beginners should have less control
movement) and desired flight characteristics (less control surface movement offers more
precise control over the glider while greater movement offers more responsiveness). As a
guide, the trailing edge of the ailerons (furthest point inboard) should be able to move 20mm
to 25mm (3/4” to 1”) up and 20mm to 25mm (3/4” to 1”) down from their neutral position
ie. a total movement of 40mm to 50mm (1 1/2” to 2”). The elevator requires less movement.
Around 10mm to 15mm (3/8” to 9/16”) up and same amount down ie. total movement of
20mm to 30mm (3/4” to 1 3/16”).
112.
The amount of control surface movement for the elevator and ailerons can be
adjusted either mechanically or electronically via some transmitters. If your transmitter has
“end point adjustment” (EPA) then adjust this setting until you achieve the desired amount
of movement for that control. To mechanically adjust the amount of movement, you can
either move the E-Z connector up or down a hole on the control horn and/or move the
pushrod clevis up or down a hole on the servo arm. To increase the amount of control
surface movement initiated by the servo you can move the E-Z connector down a hole on
the control horn (closer to the hinge line) and/or move the pushrod clevis up a hole on the
servo arm (further away from the servo). To decrease the amount of control surface
movement initiated by the servo you can move the E-Z connector up a hole on the control
horn (further away from the hinge line) and/or move the pushrod clevis down a hole on the
servo arm (closer to the servo).
