my servos for this project are the Futaba
S9001 Coreless Aircraft Servo which I'll run on 6v from my
1/4-scale J3 Cub kit provides all the linkage hardware, pre-mounted
ailerons, and, pre-drilled holes for the control horns. I needed
a 30" extension cable for each aileron servo.
finish up my aileron servo installation, I connected both wing
halves together with a Hobbico (HCAM2500) Y-Harness and checked
the alignment with a receiver and Rx. battery pack.
the cowl mounted easily, the fit with the AXI 5320 motor was rather
tight so it was critical to tape the cowl in position first, while
checking the motor rotation for rubbing, before drilling holes
for the screws.
manifolds and valve covers were painted black and silver and then
glued to the cowl with PLASTI-ZAP.
found that a spacer was needed in between the prop and the adapter
backplate. My friend, Paul Weigand who is a retired machinist
from Kodak, made one from my drawing as I had no 12mm drill bit.
The APC 20x11 e-prop will have better clearance and the metric
nut will tighten properly without hitting the untapped section
of the prop shaft.
first testing my motor direction without a prop attached, I installed
the APC 20x11 e-prop using the spacer made by my friend, Paul
Weigand. Although I couldn't find any 12mm hubs, I thought it
would look nice if I drilled out a Higley Safety Hub to fit on
the end of the prop shaft.
gear mains mounted easy with the first step being the wing strut
braces. The wheels are held by collars on either side and then
a cap covers the outside collar. It is held by three tiny screws
into the wheel hub.
ended up with two spare metal braces in the gear mains bag that
wasn't sure what do to with. It turned out that they are used
as strut supports later on in the assembly.
The gear skirts were pre-cut and covered. All the hardware needed
to mount them comes with the kit.
tail section was simple to assemble as the control surfaces
are pre-hinged and the covering is already cut away on the areas
to be glued. I used Pacer 5-minute Z-poxy to glue the horizontal
stabilizer in place and then found it easier to use thick white
glue for the vertical stabilizer. The incidences were checked
and I needed no shims for correction.
scale decals were applied to the assembled tail.
stock tailwheel assembled easily and all the parts were in a
separate bag with the instruction step printed on the bag. I
needed to shorten the supplied springs by cutting off about
1/3 of the length. If the stock foam wheel is not robust enough
for the weight, I usually replace it with a Dubro rubber tailwheel
as I am not a fan of foam wheels on models this large.
tail brace kit comes in its own bag with the instruction number
on it from the manual. The tail already has pre-installed metal
sleeves so you only need to cut away the openings. The plastic-coated
steel wire supports all four quadrants.
linkage was very easy to install. All the parts for the rudder
and elevator linkages came in their own bags. The wooden dowels
and metal rods were pre-cut and pre-bent for easy assembly.
The pre-drilled holes in the control rudder and elevator halves
were marked with pinholes through the covering. This provided
perfect alignment for the control horns.
only change from stock parts was to replace the supplied quick
links with Dubro E-Z links. The E-Z links cannot slip as the
metal rod is bent 90 degrees through the servo arm and securely
held in place. There is no need to have both ends of the linkages
ran the antenna wire from my Futaba R127DF 7-channel receiver
into a plastic tube (not supplied) and taped it into the rear
of the fuselage inside.
power the AXI 5320 motor, I am using two BalancePro HD packs in
series. The 6s and 4s packs are combined to create a 10s pack
with a 3200mAh capacity. The diagram/photo shows the hook-up for
a single 6s BalancePro HD pack using the Discharge Protection
Module (DPM) and the optional LED/Spkr module. The DPM also connects
in-line with the receiver throttle channel to ESC signal. This
allows the DPM to monitor the throttle setting and pulse it if
any one of the cells in the pack goes below the danger threadhold
that can damage the pack. Optionally, the DPMs can be used as
an alarm-only feature by monitoring the receiver throttle channel
using a "Y" adapter but not connecting the output to
the ESC. In this alarm-only mode, the optional LED/Spkr modules
will sound if a low-voltage condition exists on any cells in the
my 10s setup, the DPMs simply daisy-chain together by connecting
the power output lines in series and routing the receiver throttle
channel through one DPM and then the other DPM. The last DPM in
the daisy-chain gets connected to the ESC.
my servo and receiver power, I'm using a Power
Force Regulator from FMA Direct set to 6v. This device eliminates
the need to keep a seperate receiver pack charged, has a fail-safe
On/Off switch, and can handle the higher current needed for my
heavy duty servos. The On/Off switch has a flush slide switch
that I mounted on the side of the fuselage with the supplied plate
and hardware. I powered the regulator from the DPM connected to
the 4s BalancePro HD pack. Note that this pack must be connected
to the ground side of the wiring and the other 6s pack is wired
in series to power the Jeti 90-amp ESC. Optionally, you can also
supply the Power Force regulator with a separate 2s, 3s, or 4s
Lithium pack or 5-12 cell NiCd/MiMH pack.
instructions for the pilot tray were quite sparse so I decided
to make some simple modifications to better suit my electric conversion.
I wanted the pilot tray to be easily removeable to better access
the batteries for recharging. I cut one of the two trays so that
it could slide in and out. I then used the cut away sections to
strengthen the assembly underneith. The trays were glued with
5-minute Z-poxy and also screwed into the channel of the main
I planned to test fly the Cub the next day, I used the stock screws
to hold the pilot tray in position. See my quick release modification
using servo arms later in this review. The tray rests on a channel
on the inside of the left window area. The rubber pilot is pre-painted
and comes with a double-sided sticky foam pad to hold him on the
tray. I used some medium CA to help hold the pad to the wooden
that the front windshield is held in place with supplied screws
and rubber inserts to protect the plastic.
The windows came in the kit as a single piece for each side and
only needed to be cut on one line to separate them. I glued them
in place with Pacer POLY ZAP(tm). Designed to work on plastics,
delron, polycarbonate, nylon, and rubber...is is ideal for clear
canopies and windows. It dries clear and is non-fogging when kicker
is not used.
wing assembly is straightforward. Two aluminum rods are inserted
in the right wing first and held with machine screws in pre-tapped
holes. Once the wing is in position, the left side is held by
drilling holes into the aluminum rods via the pre-drilled holes
in the wing. The left wing half is then held by sheet metal screws.
To dissassemble, you remove the machine screws in the right wing
was rather funny as I hesitated and squinted at the first part
of the large callsign decal. I was about to apply the large decal
to the wing, leaving the others for after the maiden flight, when
I noticed that the "N" in the plane I.D. was a mirror
image. I cut out the center portion of the "N" and then
applied the decal. Once applied, I cut the correction from a piece
of black sticky-back Monocote trim sheet that I had from a previous
notified Fai Chan of Airborn Models (the U.S. distributor for
World Models) and he found that his new stock had the corrected
decal. Apparently my model was one of the last from the previous
final step of my assembly was to attach the struts and their
supports. The design of these struts were very good and proper
for a plane this size. All the wing inserts were pre-installed
so you only needed to find the pin holes in the covering. My
only change after the maiden flight will be to make the attachment
to the fuselage a quick release post and pin instead of the
supplied screws and locknuts. See below.
the initial flights, I decided that the stock foam tailwheel
was a bit weak for a Cub this size. I replaced the stock tailwheel
with a Dubro #150TW 1-1/2" solid rubber tailwheel for
quarter scale planes. The replacement Dubro tailwheel had
a slightly larger axle hole diameter but it was not sloppy
so no drilling was needed.
pilot tray was more easily removeable by creating latches from
cut off servo arms.
strut screw and nut holding it to the fuselage brace was replaced
with a hitch pin clip from Home Depot and a short brass screw
with a hole drilled in it to act as a hitch pin.