The RA Cores
GremTwin
Hyperlinked version available at http://www.racores.com/GremTwinInstructions.htm
With clickable images that expand
in color
Produced By Jim Reith RA Cores http://www.racores.com/ |
Full Kit Instructions......................................................................................................................... 3
Building the Fins.......................................................................................................................... 3
Building the Wing........................................................................................................................ 3
Building the Fuselages................................................................................................................. 6
Almost-Ready-to-Cover Kit
Instructions....................................................................................... 10
Completing the Fuselage
Pods................................................................................................... 10
Completing the Wing................................................................................................................. 11
Final Assembly.......................................................................................................................... 13
Final Balancing.......................................................................................................................... 15
1)
Select
the 1/8" sheet balsa fins and 1/8" x 1/2" x 5" sheet
balsa fin caps from the wood parts. |
|
2)
Glue
the fin caps across the top edge of the fin and tape to dry |
1)
|
2)
|
3)
|
4)
Remove
the pods from the wing and remove the servos and cover the pods as desired. |
5)
|
1)
|
|
2)
|
|
3)
|
|
4)
|
|
5)
|
|
6)
Add
nylon control horns so they line up with the servo locations you have chosen
on the fuselage pods. |
|
7)
|
|
8)
Cover
the two 1/16” plywood fin spreader pieces. Leave the center glue points and
the outside edges bare. |
|
9)
Glue
the spreaders in place being careful to mount the top spreader at a right
angle to the canopy handle. |
|
10)
Take
the fins and hold them in place and sand the contour of the wing into the
bottoms so they sit flush without wiggling. |
|
11)
Cover
the fins at this point. |
|
12)
|
1)
|
2)
Connect
the ESCs to the motors. On the side without the receiver, plug the ESC and
servo into the extensions making note of which extension is which. |
3)
On
the receiver pod side, plug the ESC into the throttle channel and the servo
into either the aileron or elevator channel (we will sort that out in radio
setup). |
4)
Plug
the servo extension for the other pod elevon servo into the open elevator or
aileron channel. (do not plug in the other ESC yet) |
5)
Program
your transmitter for “Delta” wing configuration and using one battery in the
receiver pod, bind the model. |
6)
With
your trims centered, install the servo arms in a vertical position and
install the pushrods to the elevon horns. |
7)
Test
the controls. Check that both elevons move up on up elevator and that the
elevon on the side you turn towards comes up on aileron movement. If
“Aileron” is backwards but “Elevator” is correct, swap the servo plugs for
those channels and reverse both servos on the transmitter |
8)
The
proper initial adjustment is for the rear edge of the elevons to be
1/8”-3/16” above perfectly centered. The bottom of the wing and the bottom of
the elevon should also be flat. Each elevon should raise or lower 3/8” from
center with full stick travel. |
9)
Unplug
the motor battery at this time. Remember to remove the binding plug from your
receiver. |
10)
At
this time you need to decide if you want to play with differential thrust or
not. (You can change this at any time.) a)
No
differential thrust ¨
Set
your rudder channel to zero travel ¨
Mix
the throttle channel to the rudder channel at 100% mix (so they both have the
same travel) b)
Differential
thrust ¨
Mix
the rudder channel to the throttle channel 100%. The direction of this mix
will be determined when we test since different radios have different
settings. ¨
Mix
the throttle channel to the rudder channel at 100% mix |
11)
|
12)
Secure
the plane with the propellers able to turn freely and turn on your
transmitter. Plug the motor battery into the ESC in the receiver pod. Then
plug the motor battery into the ESC in the other pod. Always plug in the
receiver pod first and unplug it last so the other ESC sees a valid signal on
start up. |
13)
Slowly
advance the throttle stick until one of the motors starts turning. If it is
the receiver pod motor, adjust the subtrim on the rudder channel until the
other motor starts up as well. The point is to make both motors start and
stop at the same time. If the non-receiver motor starts first, turn back the
rudder subtrim until they both start simultaneously. |
14)
Holding
the plane up by the canopy handle, advance the throttle to half. If you chose
differential thrust, move the rudder stick and see if you have the mixes in
the correct direction. If not, reverse the mixes. |
15)
With
just the throttle stick, you should feel balanced and equal power over the
entire throttle range. Shutdown the throttle and disconnect the motor
batteries (non-receiver pod first) |
1)
Install
Velcro in the bottom of the pods behind the motors and in front of the wing.
I generally find that it sticks better if there is a coating of glue on the
bare wood first. |
2)
Place
batteries in the pods on the Velcro and close the hatches. Do not connect the
batteries, this is just to determine the CG |
3)
With
a piece of string or wire through the hole in front of the canopy handle,
suspend the model and check the balance. The model should hang level or
slightly nose down for proper balance. Like the original Gremlin, this point
is 1.75” back from the front of the leading edge. Move the batteries as
necessary to get proper balance. |
|