Jumper 25
Instruction Man u al
16
INSTALLING THE SPINNER
1) Install the spinner backplate, pro pel ler
and spin ner cone. The spinner cone is held in
place using two 3mm x 12mm wood screws.
The propeller should not touch any part of
the spin ner cone. If it does, use a sharp
mod el ing knife and care ful ly trim away
the spinner cone where the pro pel ler
comes in contact with it.
2) Plug the four servo leads and the switch
lead into the receiver. Plug the battery pack
lead into the switch also.
3) Wrap the receiver and battery pack in
the pro tec tive foam rub ber to protect them
from vibration
INSTALLING THE RECEIVER AND BAT TERY
4) Position the battery pack in the fuel
tank com part ment and the re ceiv er just be hind
the fuel tank . Use ex tra foam piec es to hold
them in po si tion.
When balancing the airplane you may
need to move the battery or receiver
for ward or aft to achieve prop er balance.
In our test air plane, us ing a num .25-.32 two
stroke en gine, the bat tery and re ceiv er were
mount ed as per step # 4.
5) Using a 1/16” drill bit, drill a hole through
the side of the fu se lage, near the re ceiv er, for
the an ten na to exit. Route the an ten na out
of the fu se lage and se cure it to the ver ti cal
sta bi liz er us ing a rub ber band and a modifi ed
servo arm. See picture as follow.
Antenna
Rubber
Band
Modifi ed
Servo Arm
Cut
1) It is critical that your airplane be
bal anced correctly. Improper balance will
cause your plane to lose control and crash.
The cen ter of gravity is lo cat ed 7cm back from
the lead ing edge of the wing, at the fu se lage
sides. Balance the
Jumper 25
with the fuel
tank emp ty.
2) Mount the wing to the fuselage. Us ing
a cou ple of pieces of masking tape, place them
on the top side of the wing7cm back from the
lead ing edge, at the fuselage sides.
3) Turn the airplane , place your fi n gers
on the mask ing tape and care ful ly lift the
plane.
4) If the nose of the plane falls, the plane
is nose heavy. To correct this fi rst move the
bat tery pack fur ther back in the fuselage. If
this is not possible or does not correct it, stick
small amounts of lead weight on the fuselage
sides under the hor i zon tal sta bi liz er. If the tail
of the plane falls, the plane is tail heavy. To
cor rect this, move the bat tery and re ceiv er
forward orif this is not pos si ble, stick weight
onto the fi rewall or use a brass heavy hub
spinner hub, similar to those offered by Harry
Higley. When bal anced cor rect ly, the air plane
should sit lev el or slight ly nose down when you
lift it up with your fi ngers.
BALANCING
You should cut
from pushrod of
throlte or nose gear
