EF1 Power System:
Sundowner 36 will be powered in accordance to the National Miniature Pylon
Racing Association (NMPRA) Electric Formula
One (EF1) Rules using an E-flite Power
25 motor (1250Kv), 60-Amp Pro Switch-Mode BEC Brushless
ESC, 4-cell 30C 2500mAh
LiPo pack, and APC 8x8
thin electric prop.
NMPRA Electric Formula One (EF1) is a racing event for radio control
airplanes powered by electric motors. The event is intended to be easy to
get into, available everywhere, reasonably priced and using off-the-shelf
components to create the maximum amount of fun. While there is a great
diversity in equipment available for electric models, these rules are
designed to eliminate a technological advantage available to a limited few,
and allow all participants to compete on an even level.
also be using the new AR7010
7-Channel DSMX Receiver (in DSM2 mode), JR Sport MN48
Mini Servos for rudder and elevator, JR DS388
Digital Micro MG Servos for ailerons, and the optional E-flite (EFLSP200)
2" Aluminum Spinner.
first step of the installation is the horizontal stabilizer. After first
inserting the elevator into the tail, the horizontal stab is glued in place
while the elevator hangs in position. The wings are temporarily installed
to insure the stab is aligned properly. The wings fit very well against the
fuselage. The alignment pins are pre-installed so the wings simply press
the manual has instructions on cutting away the covering, it is already
done on the ARF model.
The vertical stab is glued in place next and the
top tail wheel wire section is glued to the rudder. I had no alignment
issues and the instructions in the manual were easy to follow. The rudder
hinges were secured with thin CA and the tail wheel bracket screwed to the
Rudder and Elevator Linkage Installation (page 15), it shows the elevator
servo on the same side of the fuselage (left side) as the linkage exit and
control horn. Since the control rod tubes cross inside the fuselage, the
elevator servo must be on the right side of the fuselage. My guess is that
the original prototype did not have the tubes crossed when the manual was
written. The JR Sport MN48
Mini Servos are used for rudder and elevator control.
manual does a good job of displaying the servo arm length desired so you
obtain the proper throw. All the hardware worked well and the control rods
were pre-bent and cut to the proper length. I added my own fuel tube
keepers on each clevis because the supplied keepers were dry and brittle.
main landing gear simply bolted in place. The metal gear section does have
a front and back so you need to place the angle forward as shown in a photo
in the manual.
wheel pants self align and the only issue I had was to remove a sticky
substance from the axles with Goo-Gone.
aileron servos were mounted to the covers per the manual instructions. A
6" extension lead is needed on the servo wire. There are no strings
inside the wings so you need to feed the wire through manually. It was a
fairly short run and I didn't have much trouble.
pre-bent linkage rods and hardware are all supplied so it was a quick job
to install them on both wing halves. The manual describes the servo arm
length and which hole to use on the clevis for proper throw range.
Sundowner 36 comes with three different templates, two for glow power and
one for the electric options. The Power 25 motor uses the inner holes and
the 30mm standoffs. Note that the standoff lengths are incorrect in the
manual. The center hole in the template must also be drilled out on the
firewall to allow the motor shaft collar to pass through.
triangle stock is only needed for the glow engine options and can be glued
in place after mounting the engine. For electric power, the motor box is
already much stronger than needed so it is not required to glue the
remaining triangle stock in place.
drill a few holes in the motor box for a cable wrap to feed through, it
makes the wires neat so they don't interfere with the motor. If you are
using the recommended E-flite motors and ESC, matching the motor wire color
to the ESC results in the correct rotation direction. (counter-clockwise
when viewed from the front of the model)
needed to open the floor slot a bit with a razor knife to allow the EC3
connector to pass through. No soldering required!
Prop, and Spinner:
last steps of the assembly are to mount the cowl and spinner. I used the
2" Aluminum Spinner which comes with both 4mm and 5mm collet adapters.
cowl fits like a custom glove and is secured using two 3mm socket head
screws which are hidden. After installing the canopy, you can see the
Sundowner 36 is designed for a very clean look!
initial assembly and test flight, I only had an APC 8x6 prop available so I
ordered a few 8x8 props.
receiver and battery positions were placed per the manual suggestions. With
the battery pack all the way forward, as shown, the CG was about
2-4/8" back from the leading edge. The CG range is 2-3/8" to
2-6/8" so a slightly forward CG is a good place to start. The pack can
be moved aft after each flight test, if needed.