GREAT PLANES Reactor ARF, Instruction Manual

26

5-1/4"

[133mm]

RECOMMENDED STARTING BALANCE POINT

5-1/4" [133mm] FROM THE LEADING EDGE

OF THE MIDDLE OF THE TOP WING

The recommended C.G. is 5-1/4" [133mm] from the 
leading edge of the 

middle

 of the top wing. This is 

where you should balance the model for the fi rst fl ights. 
Later, you may experiment by shifting the C.G. up to 3/4" 
[19mm] forward or 3/4" [19mm] back to change the fl ying 
characteristics. Moving the C.G. forward will improve the 
smoothness and stability, but the model will then be less 
aerobatic (which may be fi ne for less-experienced pilots). 
Moving the C.G. aft makes the model more maneuverable 
and aerobatic for experienced pilots. In any case, 

start 

at the recommended balance point 

and do not at any 

time balance the model outside the specifi ed range.

❏

 2. Use your fi ne-point felt-tip pen and a straightedge to 

draw approximately 7" [178mm] lines over the short lines you 
marked in the previous step. 

Note:

 After balancing the model 

later, the lines will easily wash off with a few paper towel 
squares dampened with denatured alcohol, or you may leave 
the balance lines on the wing for future reference.

❏

 3. The included plywood balance stand will assist you 

in balancing the model and determining how much (if any) 
additional lead ballast may be required to achieve the correct 
C.G. However, if you prefer 

not

 to use the stand and would 

rather just balance the model with your fi ngertips, apply thin 
(1/16" [1.6mm]) strips of tape over the lines so you will be 
able to feel them when balancing the model later.

Mark the Balance Point (C.G.)

The balance point (C.G.) is to be marked on the bottom
of the top wing. It will be easier to do this now, before-
mounting the wing to the fuselage. This is where the 
model will be balanced during fi nal setup later. 

MAXIMUM

FORWARD

BALANCE LIMIT

MAXIMUM AFT

BALANCE LIMIT

RECOMMENDED
BALANCE POINT

(5-1/4" [133mm]

FROM THE LE OF

THE MIDDLE OF
THE TOP WING)

FORWARD

C.G. RANGE

TEMPLATE

4.5" [114mm]

5.25" [133mm]

6" [152mm]

❏

 1. After the epoxy from mounting the top wing has hardened, 

remove the top wing from the model. Use a fi ne-point felt-tip 
pen to mark short lines directly on the bottom of the top wing 
next to the lines on both sides of the plywood 

C.G. template.

The 

middle

 line is the recommended, starting balance point 

and the 

forward

 and 

aft

 lines note the limits of the forward 

and aft balance range.