SIG Kadet LT-40 EG ARF - SIG Mfg Model Aircraft Kit History

Shown with optional Spinner
(not supplied)
Wing Span: 70 in. (1778 mm)
Wing Area: 900 (58.1 dm2)
Length: 57 in. (1447 mm)
Flying Weight: 6 - 6.25 lbs. (2720-2835 g)
Wing Loading: 15-16 oz./sq.ft. (47-49 g/dm2)
Radio Required:
4-Channel with 5 Standard Servos (glow)
4-Channel with 4 Standard Servos (electric)
Glow Power:
2-Stroke .40-.46 (6.5-7.5 cc)
4-Stroke .40-.54 (6.5-8.8 cc)
Electric Power:
500-800 watt Brushless Motor (800-1000 kv);
50-75A Speed Control (ESC)
3S-4S 4000-5000 mah Lipo Battery Pack
WARNING: Radio controlled model airplanes must be used responsibly! Just like a full-size airplane, they fly at a high rate of speed and are capable
of causing serious bodily injury and property damage if they crash. IT IS YOUR RESPONSIBILITY AND YOURS ALONE TO:
Assemble this model airplane correctly according to the instructions.
To ground test the model before each flight to make sure it is completely airworthy.
To always fly your model in a safe approved location, away from populated areas.
To always fly your model in a safe manner. Your first test flights should be made with the assistance of an experienced R/C flyer.
LIMIT OF LIABILITY: SIG Mfg. Co., Inc. guarantees this kit to be free from defects in material and workmanship at the date of purchase. The
actions, skills, and attention to detail of the modeler in assembling and flying this model airplane will ultimately determine its success and safety. Sig
Mfg. Co.'s only obligation shall be to replace those parts of the kit proven to be defective or missing. The user shall determine the suitability of the
product for his or her intended use and shall assume all risk and liability in connection therewith.
SIG MFG. CO., INC. PO Box 520 Montezuma, IA 50171-0520
© Copyright 2014, SIG Mfg. Co., Inc.
not mandatory, it is a good idea and we encourage all new R/C
fliers to join the AMA. Membership in the AMA provides you with
important liability insurance protection in case your R/C model
should ever cause serious property damage or personal injury
to someone else. Because of that liability protection, most R/C
clubs require AMA membership before you can fly at their field.
Join the AMA for the welfare of the hobby!
For more information
5161 East Memorial Drive
Muncie, IN 47302
Ph: (765) 287-1256
Welcome to the sport of radio control flying, and thank you for
choosing the SIG KADET LT-40 EG ARF. In order for your
KADET to fly as well as it was designed to, it must be properly
assembled. Work slowly and follow the instructions exactly. This
kit features a proven aerodynamic design, quality materials, and
detailed instructions, but ultimately the flyability of your finished
model depends on how well YOU put it all together.
In addition to this kit, you will need the following items to complete
your KADET LT-40 and make it flyable.
The KADET LT-40 EG ARF requires a standard 4-channel radio
system and four “standard” size servos (50-70 oz. torque). We
recommend that you buy a radio system with rechargable batteries and a battery charger.
The KADET LT-40 has earned a reputation as one of the very
best R/C trainers in the world. Tens of thousands of newcomers
have successfully learned to fly R/C with a KADET LT-40. This
ARF version of the LT-40 gets you into the air quickly. It is designed to fly with either a .40-.46 2-stroke glow engine, a .40-.54
4-stroke glow engine, or a 500-800 watt electric motor.
SIG Mfg. Co., Inc. is committed to your success in building and
flying the KADET LT-40 EG ARF. Should you encounter any
problems, or find any missing or damaged parts, feel free to
contact us by mail or telephone.
P.O. Box 520
Montezuma, IA 50171-0520
For this installation you will also need (2) 6-9 in. long servos extension chords; and (1) servo Y-harness chord. These items
are needed to complete the hookup of the aileron servos in the
wings to the receiver in the fuselage.
We urge you to read this assembly manual completely before assembly. Familiarize yourself with the parts and their assembly
sequences. The successful assembly and flying of this airplane
is your responsibility. If you deviate from these instructions, you
may wind-up with problems later on.
The biggest decision you will have to make is whether to power
your KADET LT-40 with a glow engine (2-stroke or 4-stroke) or
an electric motor. We have flown the KADET LT-40 on a variety
of both types of power systems, and we make the following recommendations based on our successful on-field experience.
If this is your first R/C Aircraft PLEASE READ THIS!
As already mentioned, the KADET LT-40 EG ARF is a perfect
model for learning to fly R/C. However, it is important to
understand that if you have never flown an R/C model before,
you will need to find a qualified R/C flight instructor to test fly the
airplane and teach you how to fly it. If this is your first radio
control model airplane, DO NOT attempt to fly it by yourself
without a qualified instructor.
We recommend the following size for the KADET LT-40 EG.
2-STROKE - .40 to .46
4-STROKE - .40 to .54
Don’t let the large size of the KADET LT-40 fool you! Due to it’s
huge wing area, very light wing loading and slow flight envelope,
these engines will provide ideal power for training or general
sport flying the KADET LT-40.
The governing body for radio-control model airplanes in the
sometimes referred to as the AMA. While AMA membership is
Whatever brand glow engine you choose, take the time to
carefully break it in according to the manufacturer's instructions.
A good running, reliable engine is a minimum requirement for the
enjoyment of this or any R/C model aircraft.
Note that the BEC feature in some ESCs does not work with 4
cell and larger lipo battery packs - only 3 cell packs. Check the
manual of your particular ESC to learn if this is true in your case.
If your BEC is only rated for 3 cells, you have three options: 1) fly
only 3 cell lipo packs (and have lower power); or 2) disable the
BEC and install a separate receiver battery pack to run the radio
and servos full time; or 3) install an aftermarket BEC that is properly rated for your setup.
Refer to the engine manufacturer’s instructions for
recommendations on proper propeller size for their engine. In
our experience, most 2-stroke .40-.46 glow engines will fly the
KADET LT-40 very nicely with a 10x6 or 11-6 prop.
We wanted to be able to fly both 3 cell and 4 cell packs interchangeably, so we elected to use a separate receiver battery
pack, since we already had it and the little bit of extra weight is
no problem for the KADET LT-40. We then disabled the BEC feature of our Castle ESC, since we no longer needed BEC. Disabling the BEC allows the speed control to be used with both 3
cell and 4 cell packs without problems. A common way to disable
BEC in many ESCs is to remove or clip the middle wire from the
plug on the ESC that goes into the radio receiver - see your ESC
manual for more guidance.
The KADET LT-40 will fly well with a 500 to 800 watt electric
brushless outrunner motor. This size motor is sometimes referred to as a "32" or “40” class motor to those who like to make
a comparison to a glow motor. Also, the motor you choose
should be rated at 800-1000 kv, in order to turn an appropriate
These motor sizes have worked well in the KADET LT-40:
❑ 3 or 4 cell 4000-5000 mAh LIPO BATTERY PACK
The KADET LT-40 will typically use a 3 cell (3S1P) 4500mAh or
4 cell (4S1P) 4500mAh Li-po pack. Again this will depend on
your choice of motor. Be sure to follow the motor manufacturer’s
What do those numbers mean?
With electric powered models there are many factors that have
a bearing on what propeller to use. The best place to start answering that question is in the instructions that come with your
motor. Another fine source of information is one of the electric
flight calculators that are available for you to use free online
(there is a good one on Castle Creations web site).
CAUTION: You must match your propeller size to the cell count
of your lipo pack, to avoid drawing too many amps and damaging
your ESC or motor.
The airplane illustrated in this manual used a Maxx Products
HC3528-1000 Brushless Outrunner Motor, with a 50 amp Castle
Creations ESC, and an APC 11x7 E propeller. This combination
gave excellent flight performance. With this motor we were able
to use either a 3 cell (3S1P) 4500mAh or a 4 cell (4S1P)
4500mAh Li-po pack interchangebly.
NOTE: This numbering system is very common, however there
are exceptions. For instance, some motor manufacturers will
list the actual diameter of the stator (armature) inside the motor
instead of the case diameter. Some may list the length of the
stator inside the motor instead of the case length. Some will
give you both if you dig far enough into their specs. Make sure
you understand the motor manufacturer’s numbering system
when shopping for a motor.
With a 3-cell (3S1P) 11.1v lipo pack, we recommend an APC
11x7E, APC 11x8E, or APC 12x6E propeller for the Maxx Products HC3528-1000 motor. All three sizes delivered good performance, very reminiscent of flying an LT-40 with a 2-stroke .40
glow engine. For a starting prop we recommend the APC 11x7E.
Other brand propellers of same size and similar design can also
be used.
A laser-cut plywood adjustable motor mount is included in this
kit. It should work perfectly for any suitable brushless outrunner
motor which has an “X” or “cross” motor mount plate on the back.
❑ 50-75 amp ESC (Electronic Speed Control)
The amp rating of your ESC will depend on your choice of motor.
Be sure to follow the motor manufacturer’s recommendation.
With a 4-cell (4S1P) 14.8v lipo pack, we recommend an APC
10x7E, APC 11x5.5E, or APC 11x7E propeller for the Maxx
Products HC3528-1000 motor.. All three sizes delivered good
performance, very reminiscent of a 2-stroke .46 glow engine. For
a starting prop we recommend the APC 10x7E or 11x7E.
We used a Castle Creations brand ESC. This is an excellent
"switching type" ESC that has a built-in 5amp BEC that is safe to
use with a 3 or 4 cell lipo battery pack. We typically see amp
draw of 30 to 48 amps, depending on whether a 3 cell or 4 cell
lipo is being used and the propeller size.
NOTE: The Castle Creations ESC that we used, as well as the
many of the other ESCs on the market, has a BEC (Battery Eliminator Circuit) built in. BEC allows you to use the same battery
pack to power both your motor and your radio system, eliminating
the normal radio battery pack. When the single battery pack runs
down in flight to a prescribed point, the BEC circuit in the ESC
will shut down the motor and leave enough power to operate the
radio while you land the model.
In addition to providing the critical charging profile needed to
safely charge lipo batteries, a lipo battery charger also includes
the capability of "balancing" the available voltage in the cells, ensuring that the battery pack is at peak capacity at the end of the
charge cycle. This translates to better flight times and a longer
life from the battery pack.
For proper assembly, we suggest you have the following tools
and materials available:
A selection of glues - SIG Thin & Medium CA Glue,
CA Accelerator, CA Debonder,
SIG Kwik-Set 5-Minute Epoxy
Assorted Screwdrivers
Pliers - Needle Nose & Flat Nose
Diagonal Wire Cutters
Small Allen Wrench Assortment
Pin Vise for Small Dia. Drill Bits
Hobby Knife with sharp #11 Blades
Small Power Drill With Selection of Bits
Dremel® Tool With Selection of Sanding & Grinding Bits
Sandpaper (such as 80 or 100 grit)
Heat Iron & Trim Seal Tool
T-Pins (such as SIG #SH-307)
Masking Tape
Soft Pencil or Fine Point Felt Tip Pen
Ruler and/or Tape Measure
90O Triangle (such as SIG #TR-036 Metal Triangle)
Alcohol or Acetone For Epoxy Clean-up
1/2” Thick Soft Foam Rubber (such as SIG #RF-240) - Used
to protect your radio receiver and battery from vibration. Can also be
used as packing around radio components or the fuel tank to keep them
from shifting around in flight.
The following is a complete list of all parts contained in this kit.
Before beginning assembly, we suggest that you take the time to
inventory the parts in your kit. Use the check-off boxes ❑ provided in front of each part description.
Fuselage & Hatch
Right Wing Panel & Aileron, hinges installed (not glued)
Left Wing Panel & Aileron, hinges installed (not glued)
Stabilizer & Elevator, hinges installed (not glued)
Fin & Rudder, hinges installed but (not glued)
Fiberglass Cowling
Aluminum Tube Wing Joiner
(3) 3” dia. Wheels
(2) Formed Main Landing Gear Wires
(2) Nylon Landing Gear Straps, for main gear wires
(4) M3 x 15mm Screws; for landing gear straps
(1) Formed Nose Gear Wire
(1) Nose Wheel Steering Arm with Set Screw
(6) Wheels Collars; for main gear(4) and nose gear(2)
(1) Fuel Tank Body
(1) Rubber Stopper Assembly, for fuel tank
(1) Fuel Pick-Up Weight, for fuel tank
(1) Fuel Line Tubing, for fuel tank
(1) Plywood Fuel Tank Support
(1) Balsa Block; for fuel tank stop block
(2) Glow Engine Mounts; for glow engines
(4) M4 x 25mm Slotted-Head Bolts, for glow engine mounts
(4) M4 x 30mm Slotted-Head Bolts, for glow engine
(4) M4 Lock Nuts, for glow engine
(1) Plywood Electric Motor Mount Box
(1) Balsa Triangle Stock
(8) M4 x 16mm Socket-Head Bolts; for electric motor
(4) M4 Split-Ring Lock Washers; for electric motor
(4) M4 Blind Nuts; for electric motor
(16) M4 Flat Metal Washers
(2) 35-1/2" long Pushrod Wires w/ Hex Nut; for elev. & rud.
(2) 7-1/8" long Pushrod Wires w/ Hex Nut; for ailerons
(1) 19-3/4" long Pushrod Wire w/ Z-bend; for nose gear
(1) 19-3/4" long Pushrod Wire; for throttle
(1) 13-3/4" long Nylon Pushrod Tube, for throttle
(4) Metal Clevis; for ailerons(2), elevator(1), rudder(1)
(4) Short pieces of Fuel Tubing; for clevis keepers
(4) Pushrod Snap Keepers; for ail(2), elev(1), rud(1)
(2) Metal Pushrod Connectors; for throttle & nose gear
(1) Nylon Clevis; for throttle
(4) Nylon Control Horns; for ail(2), ele(1), rud(1)
(12) M2 x 15mm Screws; for control horns
(4) M3 x 10mm Sheet Metal Screws; for cowling
(2) M6.5 x 45 mm Nylon Wing Bolts
(2) Velcro Straps
(2) Plastic Cinch Straps
Please check the contents of your kit box with these diagrams.
If any parts are missing, contact SIG Mfg. Co. at 641-623-5154.
Please check the contents of your kit box with these diagrams.
If any parts are missing, contact SIG Mfg. Co. at 641-623-5154.
The parts shown above are not all to the same scale.
Smaller parts are unlarged for clearer viewing. You can
measure the length of the bolts and screws using this
metric ruler.
After you have all the covering secured onto the solid areas, turn
the temperature of the iron up to approximately 300OF - 320OF
(149OC - 160OC). This is the correct temperature for shrinking
the covering material.
Your KADET LT-40 ARF is covered with ORACOVER®, a premium quality covering made in Germany, and sold in the U.S. by
Hanger-9® as UltraCote®.
ORACOVER® #10 White (UltraCote® #HANU870)
ORACOVER® #71 Black (UltraCote® #HANU874)
ORACOVER® #23 Red (UltraCote® #HANU866)
Use the iron to tighten up any wrinkles in the “open” areas of the
model (no wood underneath the covering). Glide the iron over
the wrinkle for a few seconds, then remove. Repeat until the covering is tight with no wrinkles.
If wrinkles keep coming back on the tail surfaces, you may need
to “ventilate” the areas between the ribs. Otherwise the air that
is sealed in those relatively small areas will expand when the
heat is applied and actually cause the covering to stretch instead
of shrink. Use a pin to poke a tiny hole in the covering between
each rib, on the bottom of the part. That will let the expanding
air escape and the covering to shrink properly.
If sometime in the future you need replacement covering or
matching paint for repairs, they are available from your local
hobby dealer or online from Hanger-9®.
How To Tighten Loose Covering
After you open your KADET LT-40 and take all the covered parts
out of their plastic bags, the covering may begin to wrinkle. This
is not unusual and is no cause for alarm.
Caution When Using Heat Guns: You can also use a hobby-type
heat gun to shrink the covering, but you must be careful around
seams or color joints. Getting too much heat on the seams may
cause them to "creep" or come loose. You must also be careful
when using a heat gun when working around the windshield and
side windows - heat will distort the clear plastic material.
Your airplane was built and covered in a part of the world which
has relatively high humidity and therefore, the wood was likely
carrying a fair amount of moisture. When exposed to drier air,
the wood typically loses this moisture, dimensionally "shrinking"
in the process. In turn, this may cause some wrinkles. However,
wrinkles are easy to remove by just using a hobby type heat iron.
CAUTION: Trying to remove the wrinkles by hastily going over
them with a heat gun can lead to more problems. You should
take your time to carefully go over the entire model with a covering iron, as we will describe.
Recommended Temperatures:
To adhere the covering - 220OF - 250OF (104OC - 121OC)
To shrink the covering - 300OF - 320OF (149OC - 160OC)
NOTE: In this manual, any references to right or left refer to your
right or left as if you were seated in the cockpit of the airplane.
The wings are designed as a 2-piece system, with separate right
and left wing panels joined by an aluminum tube wing joiner and
a hardwood locating pin at the rear. Due to the high strength of
the wing joiner tube, the wing panels do not need to be permanently glued together. Gluing them permanently together is optional - your call. The obvious benefit to leaving the wing panels
separate is the fact that they can be easily transported or stored.
To help protect your wings during the following steps we recommend that you cover your work surface with a soft cloth or piece
of soft cell foam.
We suggest using a model airplane covering iron for this
process. Cover the iron's shoe with a thin cotton cloth, such as
an old t-shirt, to prevent scratching the covering as you work.
❑ 1) Note that the CA Hinges are installed, but not yet glued, in
the ailerons and wing panels. The installation process for the
hinges is the same for all of the control surfaces on this model.
a) If you removed the ailerons and hinges from the wing panels when you tightened the covering material, reinstall them now.
First insert the four CA Hinges into the slots in the aileron. Put
two pins in the center of each hinge, up against the leading edge
of the aileron, to keep the hinges centered during the next step.
After covering your iron, the next step is to set the iron to the
correct temperature. This is critical for achieving a good result!
The iron should be set to about 220OF - 250OF (104OC - 121OC)
as measured on the bottom of the iron using a thermometer.
If you do not have a thermometer, you can find the correct
temperature by trial and error. Set your iron to a medium setting.
Glide the iron over some of the covering that is over solid wood,
such as the sheeted wing center section. Observe the
covering to see if any bubbles appear. If bubbles appear, the
covering is getting too hot! Turn down the temperature of the iron
and repeat the test.
If no bubbles appear, turn up the heat slightly and repeat the test.
Keep adjusting until you “zero in” on the correct temperature.
Find the temperature that will get the covering to stick down without forming bubbles or causing the seams to pull away.
Once your iron is set to the correct temperature, go over the
entire framework of the airplane, making sure that the covering
is securely bonded to the structure everywhere the covering
comes in contact with the wood underneath.
b) Now carefully insert the exposed portion of the four hinges
into the trailing edge of the wing. You will find it easiest to slide
the hinges into the slots at angle, one hinge at a time, instead of
trying to push it straight onto all the hinges at once.
c) Adjust the aileron so that the tip of the aileron is flush with
the wing tip. The ailerons should be tight against the pins in the
hinges to minimize the gap between the wing and the aileron.
The aileron is now in the proper position for permanently gluing
them in place with thin CA glue.
d) Flex the aileron down and hold it in this position. Remove
the pins from one hinge and then carefully apply 3-4 drops of
Thin CA glue directly onto the hinge in the gap. You will notice
that the glue is quickly wicked into the slot as it penetrates both
the wood and the hinge. We suggest using a fine tipped applicator on the glue bottle to better control the flow of glue.
f) Untape the string at the root end of the wing panel and
begin carefully pulling the string and the aileron chord through
the wing You will occasionally feel like the wire has become
stuck inside the wing. This is simply the plug on the end of the
servo wire hitting the side of one of the holes in the wing ribs.
Gently work the string back and forth from both ends until the
plug slips through the hole. Sometimes the servo plug comes
through all the ribs the first time without getting hung up, and
other times it seem like it gets hung up on every rib. Be patient
and don’t try to force it.
e) Turn the part over and glue the other side of the hinge.
Continue this process until you have glued both sides of all the
hinges! Keep a rag handy to wipe off any excess Thin CA glue.
(If you get some glue smears on the plastic covering, don't worry
about them right now. Once all the hinging is done, you can
clean the smears off the covering with CA Debonder).
f) Let the glue dry 10-15 minutes before flexing the hinges. At
first you might notice a little stiffness in the joint. This will go away
after the hinges have been flexed back and forth a couple dozen
For the following steps you will need:
(1) Right Wing Panel
(1) Left Wing Panel
(1) Aluminum Tube Wing Joiner
(2) Servos with Mounting Screws (not furnished)
(2) 6 in. or 9 in. long Servo Extension Chords (not furnished)
(1) Servo Y- Harness (not furnished)
❑ 1) Mount the aileron servos in the bottom of each wing panel.
a) Double check the covering around the servo openings in
each with panel to make sure the covering is sealed down tight.
b) Install the rubber grommets and brass eyelets (supplied
with your radio system) into each aileron servo.
c) Install the control arms on the two aileron servos. The arms
should be at 90 degrees to the servo when the aileron control
stick on the transmitter is in neutral and the transmitter trims are
in neutral as well.
d) Before installing the aileron servos in the wing panels you
must attach a servo extension chord to the aileron servo wire.
The typical combined length of both chords is approximately 18”
- in order to run from the servo mount at mid-wing to the receiver
which will be mounted in the fuselage. A 6" or 9” extension chord
should provide sufficient length, depending on exactly how long
the servo's own wire is. Plug the servo plug into the extension
chord and tape the plugs together for added security.
e) A string is provided in the wing panel for pulling the aileron
servo chord through the wing. Each end of the string is taped
on the outside of the wing panel. Carefully untape the string at
the servo opening and tie the end of the string securely to the
end plug of the servo wire, as shown.
g) Fit the servo into the servo mount in the wing panel. Take
up any slack in the servo chord as you insert the servo in the
mount. Use a pin vise and a small drill bit to drill small pilot holes
in the servo mount for the servo mounting screws. Use the
screws supplied with your radio system to mount the servo in
place on the servo mount. Repeat this procedure to mount a
servo in the opposite wing panel.
metal clevis halfway onto the threaded end of the Aileron
Pushrod Wire.
From the kit contents locate:
(2) Nylon Control Horns
(6) M2 x 15 mm Screws
(2) 7-1/8” long Pushrod Wires with Hex Nut
(2) Metal R/C Clevis
(2) Pushrod Snap Keepers
(2) small pieces of Fuel Tubing
❑ 2) Mount one of the Nylon
Control Horns on the bottom
of each aileron by following
these steps.
a) Cut apart the control
horn and the clamping plate.
b) Clip the metal clevis into the last hole in the nylon control
horn. Lay the other end of the pushrod wire over the outer hole
in the servo arm. Use a felt tip pen to mark the wire where it
crosses the hole. Use a pair of pliers to put a sharp 90-degree
bend in the wire at the mark.
b) Look closely and you
will see three holes pre-drilled
in the bottom of each aileron
for mounting the nylon control
horn. Run your small drill bit
through the holes to make
sure they are open all the way
through the aileron, including
the covering.
c) Start each screw partway into the holes in the control horn, as shown. Thread
the screws in until the tip of
each screw protrudes just
slightly from the bottom of the
horn base.
c) Insert the bent end of the pushrod into the servo arm, from
the top. Note: You will most likely need to use a 1/16” dia. drill to
open the hole in the servo arm to accept the pushrod wire.
d) Mark and cut off the excess end of the pushrod wire, leaving 1/8” of wire protruding below the bottom of the servo arm.
e) Clip a Nylon Snap Keeper in place on the servo end of the
pushrod wire. Snap the free end of the keeper up and over the
protruding end of the pushrod wire, underneath the servo arm.
d) Set the horn in place on
the aileron, pushing the tips of
the screws into the holes in
the aileron.
e) Thread the three screws
through the aileron simultaneously, until the tips of the
screws just begin to emerge
from the other side of the
f) Then hold the control
horn clamping plate in place
while you finish threading the
screws all the way in. When
done, you can file or grind off
the protruding sharp point of
the screws if you desire.
f) Check that the aileron servo is in neutral position and adjust
the metal clevis as needed to get the aileron in neutral position.
g) Once the ailerons are properly adjusted, insure that the
metal clevis can’t open up and come loose from the control horn
by sliding the piece of Fuel Tubing over the arms of the clevis.
Also tighten the M2 Hex Nut up against the back of the clevis.
h) Repeat Steps 3a to 3g for the other aileron pushrod.
g) Repeat Steps 2a to 2f to
install a control horn on the
other aileron.
❑ 3) Next assemble and install the aileron pushrods.
a) Slide a short piece of Fuel Tubing onto the small end of the
Metal R/C Clevis. Screw the Hex Nut on the Aileron Pushrod
Wire all the way up to the end of the threads. Then screw the
❑ 4) Test fit the two finished wing panels together with the Aluminum Tube Wing Joiner. Then test fit the wing assembly on the
fuselage. The tab that is formed by the two panels at the center,
leading edge, fits into the cutout in the front fuselage former. At
the rear, two M6.5 nylon wing bolts secure the wing to the fuselage. If you encounter any difficulties mounting the wing to the
fuselage, find the problem and fix it now. Then remove the wing
from the fuselage and set it aside.
e) Use a fine line felt tip pen to mark some guide lines on the
stabilizer that will make it easy for you to realign the stab after
the glue is applied in the next step. Then remove the pins and
take the stabilizer off the fuselage for for the next step.
For the following steps you will need:
(1) Fuselage
(1) Wing
(1) Stabilizer & Elevator set
(1) Fin & Rudder Set
(2) Nylon Wing Bolts
(2) Nylon Control Horns with Clamping Plates
(6) M2 x 15 mm Screws
f) Glue the stabilizer permanently onto the rear of the fuselage. We suggest using slow drying epoxy glue for this job to
allow time to position the stab accurately and make any final adjustments that might be needed. Use pins to hold stab in place.
Re-check the alignment. Wipe away any excess epoxy with rubbing alcohol and a paper towel. Allow the glue to dry completely.
❑ 7) Mount a nylon control horn on the bottom of the elevator,
using the same techniques you used for the aileron control horns
back in Steps 2a to 2f on page 8. Three holes are already predrilled in the elevator for the mounting screws.
❑ 5) Notice that the Stabilizer & Elevator are hinged together,
but the hinges are not glued in place. Refer back to Step 1) on
page 6 of this manual for instruction on permanently gluing in
the CA Hinges using Thin CA adhesive. Also glue in the Fin and
Rudder hinges at this time. Let dry.
❑ 6) Next permanently glue the Stabilizer onto the fuselage.
a) First test fit the stabilizer/elevator assembly on the fuselage. Eyeball the location as best you can, and then temporarily
pin the stabilizer to the fuselage.
❑ 8) Mount a nylon control horn on the LEFT side of the rudder.
b) Bolt the wing in place on the fuselage with the nylon wing
bolts provided.
c) Carefully check the alignment of the stabilizer to the wing.
Use a tape measure to measure the distance from each stab tip
to the back edge of the wing - the distance should be equal on
both sides. Adjust if necessary.
❑ 9) Test fit the fin/rudder assembly in place on top of the stabilizer. Check to see that the fin sits flush and perpendicular to the
stabilizer. When satisfied with the fit, glue the fin in place using
slow drying epoxy glue. Make sure the fin is 90 degrees upright
to the stab. Let dry.
d) Next view the model from directly in front. Check to see if
the stabilizer is level with the wing. You should find it to be very
close. If necessary use a sanding block to fine tune the stabilizer
platform to level the stabilizer to the wing.
For the following steps you will need:
(1) Fuselage
(1) Fuselage
(2) Formed Main Landing Gear Wires
(1) Formed Nose Gear Wire
(1) Nose Gear Steering Arm with Set Screw
(3) 3” dia. Wheels
(2) Nylon Landing Gear Straps
(4) M3 x 15mm Screws
(6) Wheel Collars
❑ 14) Slide a wheel collar onto the axle of nose gear wire. Slide
it all the way up against the bend of the wire, as far as it can go.
Tighten the wheel collar set screw firmly. Then install a wheel
and another wheel collar onto the axle. Make sure the wheel
turns freely after you tighten the outer wheel collar.
❑ 10) Locate the two Main Landing Gear Wires and the Nose
Gear Wire. Inspect the ends of all the wires for burrs. If any are
found, use a file or sandpaper to remove them.
❑ 15) Install the nose gear steering arm and nose gear wire into
the nylon nose gear bearing that is already mounted onto the
front of the firewall. But before you do, note that the front of the
top leg of the nose gear wire has a flat spot which the steering
arm set screw will engage.
❑ 11) Slide a wheel collar onto the axle of one of the main landing gear wires. Slide it all the way up against the bend of the
wire, as far as it can go. Tighten the wheel collar set screw firmly.
Then install a wheel and another wheel collar onto the axle.
Make sure the wheel turns freely after you tighten the outer
wheel collar. Repeat the process to install the wheel on the other
main landing gear wire.
Hold the steering arm in position in the nose gear bearing while
you slide the top leg of the nose gear wire up through the holes
in both the nose gear bearing and steering arm. When the top
of the coil in the wire is approximately 3/16” - 1/4” from the bottom
of the fuselage, tighten the steering arm set screw.
❑ 12) Fit the main landing gear wires into the grooved block in
the bottom of the fuselage. Holes have been pre-drilled in the
block to receive the short upper arm of the gear wires. Push the
wires down tight into the groove. NOTE: If the wire doesn't want
to fit completely down into the groove of the landing gear block,
it may be necessary to remove a little material from the inside
edge of the hole to allow for the radius of the bend in the wire.
Do this with a round file or modeling knife.
❑ 13) Place the two nylon landing gear straps over the main
gear wires as shown in the picture. Mark, then drill four 1/16"
pilot holes for the screws. Use four M3 x 15mm Screws to mount
the straps to the fuselage.
For this section you will need:
(1) Fuselage Assembly
(2) 35-1/2" long Pushrod Wires with Hex Nut
(2) Metal RC Clevis
(2) small pieces of Fuel Tubing
(2) Pushrod Snap Keepers
(1) Radio Receiver (not furnished)
(2) Servos with Mounting Screws (not furnished)
e) Unclip the clevis from the rudder control horn so that you
can now pull the wire pushrod as far forward into the radio compartment as possible, to make is easier to complete this step.
Mark and cut the servo end of the pushrod wire 1/4" past the
mark you made in the last step. Then use a pliers to put a sharp
90-degree bend in the wire.
❑ 16) Install the rudder and elevator servos inside the fuselage
in the built-in plywood radio mounting tray. The rudder servo
goes on the left side of the airplane, and the elevator servo goes
on the right side. (The servo opening in the front of the tray is for
the throttle servo in a glow installation.) Be sure to drill pilot holes
through the plywood tray for the servo mounting screws.
❑ 17) Install the rudder pushrod.
a) First slide a small piece of Fuel Tubing onto the small end
of the Metal R/C Clevis. Next screw the Hex Nut that is on the
Pushrod Wire all the way up to the end of the threads. Then
screw the metal clevis halfway onto the threads.
f) With the pushrod still disconnected from the rudder, remove
the servo control arm from the servo. Install the servo arm and
a nylon pushrod snap keeper on the end of the pushrod, as
shown. Then re-install the servo arm on the servo.
NOTE: Drill out the holes in your servo arms with a #49 (.073”)
or 5/64” (.078”) dia. drill bit so the pushrod wire will fit.
b) Locate the exit slot for the rudder pushrod on the top left
side of the fuselage alongside the fin. Just inside the slot is the
end of the rudder pushrod sleeve (tube) that is built into the fuselage. The sleeve extends from the slot at the rear, forward into
the cabin area of the fuselage, and aligns with the rudder servo
arm. Slide the plain end of the long rudder pushrod wire into the
end of the sleeve at the tail end. Slide it in until you can clip the
clevis into the outer hole of the rudder control horn.
c) Lock the rudder in neutral position. You can use tape to
secure it in neutral; or another method that we prefer is to use
two scrap balsa wood sticks or dowels, with small rubber bands
holding them together at each end, to clamp the rudder in line
with the fin (as shown in the this photo).
g) Make sure that the rudder servo is in neutral position and
then adjust the metal clevis at the tail end as needed to get the
rudder in perfect neutral position.
h) After the rudder is properly adjusted, insure that the metal
clevis can’t open up and come loose from the control horn by
sliding the small piece of fuel tubing over the arms of the clevis.
Also tighten the M2 Hex Nut up against the back of the clevis
d) Inside the fuselage, hold the pushrod wire over the rudder
servo output arm and mark the wire where it crosses over the
outer hole in the arm. Make sure the servo is in neutral position.
❑ 18) Locate the exit hole for the elevator pushrod inside the
rear of the fuselage, and then repeat Step 17 in its entirety to install the elevator pushrod.
For this section you will need:
(1) Fuselage Assembly
(1) 19-3/4" long Pushrod Wire with Z-Bend on one end
(1) Metal Pushrod Connector
❑ 19) The nose gear pushrod consists of a wire pushrod with a
Z-bend on the end that hooks to the nose gear steering arm; and
a metal pushrod connector on the servo end.
a) Begin by installing the metal pushrod connector in the rudder servo arm, with one hex nut on each side of the arm. Note
that the pushrod connector goes on the opposite side of the
servo arm from the rudder pushrod. Also, if your rudder servo
arm has three holes in each side, put the pushrod connector for
the nose gear in the middle hole.
Skip this section if your using a glow engine power setup.
For this section you will need the Fuselage and:
(1) Fiberglass Cowling
(4) M3 x 10mm Screws
(1) Plywood Electric Motor Mount Box
(1) Balsa Triangle Stock
(4) M4 x 20mm Socket-Head Bolts
(4) M4 Flat Metal Washers
(4) M4 x 16mm Socket-Head Bolts
(4) M4 Split-Ring Lock Washers
(4) M4 Blind Nuts
(2) Velcro® Straps
(1) Electric Motor, ESC, Prop, Lipo Battery (not furnished)
Tighten the two hex nuts of the pushrod connector securely
against the top and bottom of the servo arm. If you take the set
screw temporarily out of the pushrod connector, you can use a
small screwdriver to go down through the connector body to hold
the bolt, which makes it much easier to tighten the hex nuts.
❑ 20) NOTE: The mounting of the electric motor in the KADET
LT-40 assumes that your motor has a typical "X" or "cross"
mounting plate on the back of the motor.
b) Now slide the plain end of the nose gear pushrod wire into
the fuselage from the front. You will find an easy path from the
steering arm back to the rudder servo through the cutouts in the
fuselage structure.
Also note that the firewall portion of the laser-cut plywood motor
mount is adjustable fore and aft to accommodate different length
motors. In this step we will adjust the motor mount for your particular electric motor. For the KADET LT-40 we need a total distance from the back of the plywood motor mount box to the
motor’s thrust washer to end up exactly 4-3/8”. This distance
allows the cowling to fit properly.
a) Assemble your motor according to the manufacturer's instructions. Then carefully measure the distance from the back
of the mounting plate to the front of the thrust washer *.
* The “thrust washer” is the part of the prop adaptor where the
back of the propeller will be located.
c) When pushrod wire reaches the rudder servo, insert the
end of the wire into the pushrod connector.
d) At the front, you will need to temporarily remove the steering arm from the nose gear bearing to hook it onto the Z-bend of
the pushrod. Then re-install the nose gear.
e) Adjust the overall length of the pushrod by sliding it in or
out of the pushrod connector until the nose wheel is straight
when the rudder is straight. Then tighten down the set screw in
the pushrod connector
b) Subtract the measurement taken in the previous step a)
from 4-3/8”. The result is the distance you need to locate the
front of the firewall from the back of the plywood motor mount
box. (With the motor we are using in these photos, the motor
measurement is 2-7/8”. So 4-3/8” minus 2-7/8” = 1-1/2”. Your result may be different depending on your motor.)
c) Carefully measure and mark the distance determined in the
previous step from the back edge of the motor mount box towards the front. Do this along side each of the adjustment slots
on both sides of the box (four marks total).
d) After you have all four slots marked, carefully align the front
face of the firewall to line up with the marks. Make sure you end
up with the firewall straight and square in the box. If it is not,
recheck your marks and adjust as necessary.
e) Tack glue the firewall in place. Recheck once more to make
sure that the front of the firewall is at the correct distance from
the back of the motor mount box. That distance plus the length
of your motor must equal 4-3/8”. When satisfied it is correct, glue
the firewall securely to the rest of the motor mount box.
back side of the firewall. Put a couple drops of glue on the
flanges of the blind nuts to secure them to the plywood. Be careful not to get any of the glue in the threads.
❑ 22) A long piece of balsa triangle stock provided to reinforce
the motor mount. Measure, cut and glue pieces of triangle stock
in the corner joints of the motor mount box.
❑ 21) Note the laser scribed lines on the front of the plywood
firewall that indicate the airplane’s thrust line.
a) Use a small straight edge and sharp pencil to extend the
45o scribed lines out to the edges of the plywood.
❑ 23) Bolt the plywood
motor mount box to the
fuselage with M4 x 16mm
Socket-Head Bolts and
M4 Flat Metal Washers.
Note that two access
holes have been provided in the bottom corners of the firewall to
allow easy access with a
ball-end hex wrench.
❑ 24) If you have not already re-attached the X mount plate to
the back of your motor, do so now. Then use (4) M4 x 16mm
Socket-Head Mounting Bolts and Lock Washers to bolt your
motor in place on the plywood motor mount box.
b) Remove the X mount plate from the back of your motor and
center it on the firewall, using the lines as your guide. When you
are sure it is properly located, mark the mounting hole locations.
❑ 25) Install your ESC
a) First solder appropriate battery connectors (not supplied)
to the battery leads of your ESC.
c) Set the X mount aside and drill out the mounting holes with
a 7/32" dia. drill. Install four M4 Blind Nuts in the holes, on the
b) Decide on a good location for the ESC in the nose of the
airplane and figure out the best way of routing the motor wires.
The most likely location to mount the ESC is against one of the
fuselage sides, out of the way of the battery pack. Make sure
the ESC is mounted low enough that it does not interfere with
the fit of the Hatch. Trial fit the hatch to make sure. Mount the
ESC to the airplane structure using a method of your choice like double-sided tape or Velcro® (neither of these are provided).
c) Connect the ESC motor wires to the motor. You may wish
to use a piece of household tape (any type) to secure the motor
wires against the fuselage, so they will be out of the way during
battery changes. The neater you can make your installation, the
easier battery changes will be.
❑ 27) Mount the cowling on the fuselage with the four M3 x
10mm Screws provided. Notice that the holes for the cowl
mounting screws are already pre-drilled in the cowling.
a) First test fit the cowling on the fuselage. As you pass it
over the motor, make sure all the wires are out of the way. Carefully adjust the exact position of the cowling. Make sure you have
adequate clearance between the front of the cowl and the back
of the propeller, and that the prop shaft is centered in the hole.
Use low tack tape to hold the cowling in place for the next step.
b) Use a 5/64" or #45 bit to drill a pilot hole for the top left cowl
mounting screw. Center the drill in the hole in the cowling and
drill into the fuselage side. Install an M3 x 10mm screw in the
pilot hole - do not over-tighten the screw.
c) Recheck the position of the cowling and make any adjustments needed to get it back in position.
d) Now drill another pilot hole for the upper screw on the other
side of the cowling. Install the screw.
e) Repeat this process to install the two bottom cowl mounting
screws. Remove all the tape.
d) Route the ESC servo wire back to the receiver and plug it
in. Operate the motor and check the direction of rotation. Always
do this without a propeller attached, for safety! If you need to reverse the rotation, refer to the instructions that came with the
motor and ESC. Normally it is just a matter of switching connection of one of the three motor wires to the ESC.
❑ 26) Two velcro straps are provided to hold your lipo battery
pack in place inside the fuselage. Feed the straps down through
the slots in one side of the plywood battery tray, and then up
through the other side, as shown in the photo. TIP: A sharp
pointed hobby knife and a tweezers are helpful for this task.
Note: The two velcro straps can be shortened to fit your battery
packs. Typically batter packs suitable for the KADET LT-40 will
not need the full length straps. The excess length just clutters
up the compartment. Trim off the plain end of the straps to
achieve a length that fits your packs. For instance 3” was cut off
the plain end of the straps shown in this photo, to eliminate clutter
in the airplane and to make the straps easier to hook up.
With a fully cowled motor, it is very important to make sure your
electric power system is getting proper cooling. Air flowing into
the front of the cowling must have a place to exit the cowl. In fact
it’s best to have more air exit area than inlet area to create a positive air flow through the cowling - an actual suction effect - drawing the heated air out of the cowling so that more cool air can
come in. This positive air flow keeps your motor running cool.
The KADET LT-40 cowling has a large opening in the front to let
cooling air in, and a generous sized opening at the bottom rear
edge of the cowling to let the air out. Cooling air can also exit
the fuselage through the open tail end of the airplane. In most
cases these openings should provide adequate cooling for your
OPTIONAL SPINNER: A Spinner is not supplied with this kit because most electric flyers will prefer let the maximum amount of
cooling air enter the front of the cowling. If you wish to use a
spinner the correct size is 2 inch diameter.
Make sure the neither the velcro straps nor the battery pack will
interfere with the operation of the nose gear pushrod.
Optional: In addition to the two velcro straps, it is always a good
idea to use regular velcro tape (not furnished) on the bottom of
your battery packs, with the mating part on the top surface of the
plywood battery tray. This will insure that your battery pack will
not move around during flight.
The installation of your electric motor system is now completed.
Skip the next section on glow power system installation and proceed directly to Page 19 for your next steps.
reach the back of the tank, without getting stuck on the walls of
the tank. Test fit in the tank and adjust as necessary. With the
stopper assembly in place, the fuel clunk should sit just in front
of the rear of the tank and move freely inside the tank. If not pull
the assembly back out and trim the tubing back until the stopper
moves freely. The top of the vent tube should rest just below the
top of the tank. It should not touch the top of the tank.
Skip this section if your using an electric power setup.
The KADET LT-40 is a large airplane and is very adequately powered with the 2-stroke or 4-stroke engine sizes suggested. The
airplane does not benefit from being over-powered. Doing this
tends to put undue stress on the airframe without any real gain
in performance. This airplane was always intended to "fly on the
wing", not on excessive power.
The engine shown in these instructions is a typical .46 size 2stroke engine. The engine is mounted in the upright position,
providing easy access for field adjustments. The engine installation for either 2-stroke or 4-stroke power plants is basically the
same. The main difference is often times the throttle arm location
on the carburetor. The materials provided in this kit should be
useful for almost any 2-stroke engine installation. Installation of
a 4-stroke engine may require some alterations and/or specialized fittings (not supplied).
d) Once you are satisfied with the fit of both the fuel clunk line
and the vent line you can tighten the screw to expand the rubber
stopper and seal the stopper in the tank. Do not over tighten the
screw as it can cause the tank to split. Attach three 6-inch
lengths of silicone fuel tubing (not furnished) to the tank and label
them appropriately as VENT, CARB, and OPTIONAL so you can
identify them after the tank is installed in the airplane.
For this section you will need the Fuselage and:
(1) Fiberglass Cowling
(4) M3 x 10mm Screws
(2) Nylon Engine Mounts
(4) M4 x 25mm Slotted-Head Mounting Bolts
(4) M4 x 30mm Slotted-Head Mounting Bolts
(8) M4 Flat Metal Washers
(1) Fuel Tank
(1) Rubber Stopper Assembly
(1) Fuel Pick-Up Weight (clunk)
(1) Fuel Line Tubing for inside tank
(1) Plywood Fuel Tank Support
(1) Small Balsa Block
(1) Nylon Throttle Pushrod Tube
(1) 19-3/4" long Wire Throttle Pushrod
(1) Metal Pushrod Connector with Set Screw and Hex Nuts
(1) Nylon RC Clevis
❑ 29) The rear of the tank will be supported by a Plywood Fuel
Tank Support. Notice that one side of the support has a notch to
clear the nose gear pushrod. Glue the plywood fuel tank support
securely in place.
You will also need to acquire these items (not supplied):
(1) R/C Engine and suitable Propeller
(3) 6 in. lengths of Silicone Fuel Line Tubing
(1) Silicone Sealer (common kitchen & bath type)
❑ 28) Fuel Tank Assembly
a) Locate the Rubber Stopper Assembly. Note that there are
three nylon tubes going through the rubber stopper.
One of the tubes will be used for the Fuel Pickup Tube, which will
then connect to the engine carburetor.
Another tube will be used for the Tank Vent, which is most often
then connected to the pressure fitting on the muffler.
The third tube can be used for a separate fill line if you desire, or
it is more often capped off and the tank filling is done by removing
the fuel line at the carburetor and filling through that line.
❑ 30) Install the Fuel Tank in the fuselage.
a) First trial fit the tank in place inside the fuselage to familiarize yourself with the installation. Slide it in from the back,
through the rear fuel tank support, and up to the back of the firewall. The neck of the tank will poke into hole in the back of the
firewall. Take the tank back out for the next step
b) Apply a generous bead of "silicone sealer" around the neck
of the fuel tank (household bathroom silicone sealer is available
at most hardware stores - not furnished).
c) Then slide the fuel tank in place in the fuselage, up against
the back of the firewall, with the neck of the tank in the hole in
the firewall. If excess silicone sealer oozes out onto the front of
the firewall, clean it off.
b) Orient the stopper so that one of the tubes is towards the
top and then bend that tube up at a 45-degree angle. This tube
will be the tank vent line. Do not apply heat to the tube - it will
bend without heat. Just overbend it to nearly 90-degrees and
then let it relax, to see where it will end up. Repeat if necessary
until the tube will stay at 45-degrees.
c) Attach the metal Fuel Pick-Up Weight on one end of the silicone Fuel Line Tubing that goes inside the tank. Cut the other
end of the fuel line tubing to a length that will allow the clunk to
the firewall. This is the correct distance needed for the cowling
to fit properly.
❑ 34) Double check to make sure that the engine is situated
square on the mounts, and then carefully mark the locations of
the engine mounting holes onto the beams of the engine mounts.
❑ 35) Now set your engine aside and unbolt the engine mounts
from the firewall. Drill clearance holes for your engine mounting
bolts all the way thru the engine mount beams at the four locations you marked in the previous step. We recommend that you
secure the engine mounts in a vise while you drill the holes. Also,
if at all possible use a drill press to drill these holes. You can drill
them by hand, but if you have access to a drill press, the job will
be much easier and the holes will be straighter.
d) A small balsa wood block is provided as a stop to keep the
fuel tank from sliding backwards. Glue the block to the tank floor,
up against the back of tank.
ENGINE MOUNTING BOLTS: Four sets of M4 x 30mm SlottedHead Mounting Bolts, Flat Washers, and Lock Nuts have provided for mounting your engine to the engine mounts (provided
they will fit your particular engine). We realize that these M4 bolts
may be too big for some engines. Engines in the .40 to .46 size
range can vary in the size of mounting bolts required. In other
words, some .40-.46 engines have small holes in their case for
4-40 bolts only; while other .40-.46 engines have holes large
enough to accommodate 6-32 or M4 mounting bolts. If your engine is made for a smaller size bolts, you will have to obtain those
bolts and nuts from your local hobby shop.
Drill 1/8" dia. holes for 4-40 mounting bolts (not supplied).
Drill 5/32" dia. holes for 6-32 mounting bolts (not supplied).
Drill 11/64" or #18 dia. holes for M4 mounting bolts provided.
The engine shown in these instructions is a typical .46 size
2-stroke engine. The engine is mounted in the upright position,
providing easy access for field adjustments.
SAFETY ISSUE: Do not drill and tap these engine mounts.
Doing so may weaken them and cause failure. Drill holes in the
mounts big enough to freely pass the bolts and then use lock
❑ 31) Bolt the two Engine Mounts on the front of the firewall,
using M4 x 25mm Slotted-Head Bolts and M4 Flat Washers provided. The blind nuts are already installed in the back of the firewall. Look ahead to the next photo and note the proper
orientation of the engine mounts, with the larger side-web towards the top. Also notice that the holes in the mounts for the
bolts are slotted to allow you to adjust the spacing of the mounts
to fit your engine. So leave the mounting bolts slightly loose for
now. Do not tighten them until the next step.
❑ 36) When you're finished drilling the holes, bolt the engine to
the Engine Mounts. Then bolt the entire engine/engine mount
assembly back onto the front of the Firewall. Tighten all bolts
and nuts securely.
❑ 37) Connect the fuel tank to the engine using heat-proof silicone based fuel line tubing (not supplied). Recall from Step 28
the purpose for each fuel line.
❑ 32) Set your engine in place on the beams of the engine
mounts. If the beams of the mounts are too far apart to fit your
engine, slide the mounts closer together. If they are already too
close together, slide them apart. After you get the mounts in correct position, tighten all four mounting bolts, securing the engine
mounts on the firewall.
The fuel tube that runs to the very back end of the fuel tank is
the CARB feed line. Connect it to the engine carburetor.
The tube that goes to the top front inside the tank is the VENT
line. Connect it to the pressure fitting on the muffler.
The third tank line is plugged shut in most Kadet installations.
Plug it by putting on a short piece of fuel tubing and then plugging
the tubing with a spare steel bolt. See photo next page.
❑ 33) Slide the engine forward or aft on the engine mounts until
the front of the engine's thrust washer is 4-3/8" from the front of
❑ 40) Screw the nylon clevis onto the threaded end of the
pushrod. Then test fit the throttle pushrod wire in the airplane,
sliding the plain end of the wire in from the front. Steer the
pushrod through the slotted hole in the firewall; then through the
hole in the rear tank support; and then back to the pushrod connector on the servo. Slide the end of the wire into the pushrod
connector, but don’t tighten the set screw at this time.
❑ 41) Now take a look at connecting the nylon clevis at the front
of the pushrod to the carb arm. With a typical 2-stroke engine
you will most likely find that the clevis does not line up with the
carb arm. If that is the case simply take the pushrod back out of
the airplane and use a pliers to bend the end of the pushrod in
an offset pattern, as shown below, using two 45o bends. In our
installation we needed to offset the end of the pushrod about 3/8"
in order to line up directly with the carburetor arm.
To fill the fuel tank when the 3rd line is plugged shut, first remove
the other two fuel lines from the carburetor and the muffler pressure fitting. Pump the fuel into the tank through the fuel pick-up
line (carb line). When the tank is full, fuel will begin to run out
the vent line (muffler line). Stop pumping when you see the fuel
start to come out the vent line! Re-connect the fuel lines and
you are ready to start the engine.
The supplied throttle pushrod assembly consists of a wire
pushrod running inside a nylon pushrod tube. On the threaded
end of the pushrod you will have a Nylon RC Clevis. For a typical
2-stroke installation we prefer to connect this end of the pushrod
to the carburetor arm. The plain end of the pushrod wire will connect to the throttle servo using a Metal Pushrod Connector.
❑ 42) When you are ready to put the pushrod back in the airplane for the final time, first slip the Nylon Throttle Pushrod Tube
over the pushrod wire. After you get the pushrod assembly in
the airplane, adjust the location of the nylon tube so approximately 1" of the nylon tube is sticking out in front of the firewall.
Then glue the tube to the plywood rear tank support, to keep it
from moving.
❑ 38) The first step is to install your throttle servo in the fuselage, using the rubber grommets, eyelets, and screws that came
with the servo. Mount the throttle servo in the front opening of
the servo tray, with the servo control arm to the front.
❑ 39) Install the metal pushrod connector in the throttle servo
arm, with one hex nut on each side of the arm. You will need to
drill out the hole in the servo arm with a 5/64" dia. (or #47) drill
bit to accept the threaded portion of the pushrod connector.
Tighten the two hex nuts of the pushrod connector securely
against the top and bottom of the servo arm. If you take the set
screw temporarily out of the pushrod connector, you can use a
small screwdriver to go down through the connector body to hold
the bolt, which makes it much easier to tighten the hex nuts.
a) Clip the nylon clevis onto the carburetor and set the carb
in the middle of its travel. Set the throttle servo in the middle of
its travel and then tighten the set screw in the pushrod connector
to secure the pushrod wire.
b) Turn on your radio and check the operation of the throttle
pushrod. Make adjustments as needed to get full range of carburetor travel. You can adjust the overall length of the pushrod
with either the nylon clevis or with the pushrod connector. Also
use the EPA (End Point Adjustment) feature of your transmitter
to accurately dial-in the desired amount of servo travel. Also
opening is big enough for you to slip it over the engine and place
it in correct location on the model, then continue modifying the
opening as needed to provide access to the needle valve and
the fuel line tubing at the carb.
make sure there is no binding in the throttle linkage, which could
cause unnecessary battery drain.
Ideally, this is the range of throttle moment you want to achieve:
NOTE: Adjusting carburetor linkage can be a little tricky! If the
throttle servo is binding or “stalling” because it has too much
travel compared to the carburetor travel, try using your transmitter’s End Point Adjustment “EPA” feature to dial in the proper
amount of travel. If that doesn’t work, you may need to move the
pushrod connections to different holes in the servo or carburetor
arm. You may also need to loosen the pushrod connector to readjust the overall pushrod length. All or some of these things
may need to be adjusted to get the carburetor working properly.
OPTIONAL SPINNER: This photo shows the use of an optional
spinner, which is not supplied with this kit. If you wish to use a
spinner the correct size is 2 inch diameter.
❑ 45) When satisfied with the opening in the cowling, mount the
cowl to the fuselage with the four M3 x 10mm Screws provided.
a) Begin by placing the cowl over the engine and in correct
position on the front of the fuselage. Be sure to leave a 3/32” to
1/8” gap between the front of the cowling and the back of the propeller, for clearance. Tape the cowling in correct position using
a low-tack tape.
e) At the rear of the cowl there are four small pre-drilled
mounting holes - two on each side of the airplane. Use a 1/16"
drill bit to make a guide hole through one of the cowl mounting
holes and into the fuselage side. Install an M3 x 10mm screw
into the drilled hole and screw it in place - do not over-tighten the
screw. Recheck the overall fit of the cowl and make any adjustments needed to the tape to hold it in correct position. Then on
the opposite side of the fuselage, drill another 1/16" guide hole
and install a screw into that hole. Repeat this process for the remaining two cowl mounting holes. Remove the tape.
❑ 44) An opening needs to be made in the top of the cowling to
clear the engine cylinder head and carburetor. Don't be tempted
to quickly dive in with a knife and start removing large chunks of
material. You will achieve a lot better result if you take the time
to develope a pattern and mark it on the cowling for guidance
when you are cutting.
a) Begin by marking a centerline on the top of the cowl.
b) Then take width and length measurements off your engine
and transfer them to the top of the cowl, using the centerline as
the base reference point. The simple pattern shown in the previous photo was quickly made by measuring the diameter of the
engine head and the overall length of the engine. It will serve as
an undersize starting point for removal of material.
c) A Dremel® Tool, or similar powered hand-tool, with a 5/8"
dia. coarse grit sanding drum is without a doubt the best tool to
use for removing the material inside the lines quickly, easily and
accurately. However, if you do not have access to such a power
tool, you can cut the opening with a drill, a hobby knife, and a file
- by first drilling a series of almost touching holes inside the pattern lines (1/8” dia. works well); then using the knife to cut through
the connecting material between each hole; and finally finishing
the edges of the opening with the file or a sanding block.
After you finish the final steps of the radio installation on the next
page, you should seal the Hatch/Windshield onto the fuselage
to prevent fuel and exhaust residue from getting inside the fuselage. The reason we built a removable hatch into this airplane
was to provide easy access to the battery compartment when
using an electric motor for flight. Obviously, with a glow engine
you do not need regular access to this area of the airplane. We
recommend tack gluing the hatch in place with several small
spots of glue along its edges. Then seal over the seams with either clear tape or white covering material (not supplied). This is
reversable if you ever need access to the fuel tank in the future.
Be aware that there are no hard and fast "rules" for the exact perfect shape for openings in a cowling. Most important, make it big
enough to provide the access you need to the engine. The best
method is to "sneak up" on these openings, continually trial fitting
the cowling over the engine until it finally fits properly. Once the
The installation of your glow engine is now completed.
A standard "Y-harness" chord (not supplied) is needed to connect
the two aileron servo chords to the receiver. Plug the single end
of the Y-harness into the aileron port of the receiver. It will remain
plugged into the receiver permanently, even when the wing is
taken off the airplane. At the flying field, when putting the wing
on the airplane, plug the two aileron servo chords into the twin
plugs of the Y-harness. Then bolt on the wing.
Both glow and electric power users resume assembly here.
NOTE: The receiver and servos of different brand radios are not
all the same size! Consequently, it is practically impossible for us
to guarantee that every word and picture in this next sequence
will pertain exactly to your installation. As you go along, you may
notice some differences between your radio equipment and ours.
Nonetheless, most of the radio system components will be close
enough in size and appearance that you should be able to figure
out for yourself how to handle any minor differences. Follow the
instructions as closely as possible. If you have any questions,
seek the advice of an experienced modeler. The installation of
the control system in your new model is very important! It must
be done correctly in order for your airplane to fly successfully.
Wrap the receiver in a layer of soft foam rubber to insulate it from
engine vibration and shock. Use tape or rubber bands to hold
the foam around the receiver. Secure the receiver in the cabin
of the airplane. Mount the receiver antenna according to the
radio manufacturer’s directions.
Your KADET LT-40 is completely assembled. However, it is NOT
ready for flight! There are a few very critical pre-flight tasks we
must perform before flying. These are extremely important and
should be approached with patience and care.
If you are using a receiver battery pack (which is all glow engine
users, as well as electric motor users who are not using BEC,
you will need to install your receiver battery pack inside the fuselage. Wrap the battery pack with a single layer of soft foam rubber (not supplied) to insulate it from vibration and shock. Use
tape or rubber bands to hold the foam around the battery.
This may be the single most important step in preparing your airplane for flight. All airplanes, model or full-size, must be accurately balanced in order to fly successfully. An airplane that is
not properly balanced will be unstable and will most likely crash.
The battery pack can be located anywhere in the front of the
fuselage that you can find room - from just behind the firewall on
top of the fuel tank (if it is a thin flat pack); to the cabin floor just
in front of the fuselage servos. The battery pack can actually be
used as an aid to achieve proper “balance” of the airplane (coming up soon). For now, leave the receiver battery pack loose on
the bottom of the fuselage in front of the servos. Later, when the
Center of Gravity (CG) is established, the final position of the battery pack can be determined. At that time you can use the plastic
cinch straps provided, or some other method, to secure the battery pack so it can’t move around. Make sure the battery pack
does no interfere with the operation of any pushrods.
It is impossible to produce a model airplane kit that will automatically have the correct balance point. Not everyone uses the
same engine/motor or radio gear - and all those items can vary
in weight! You might be surprised to know that .40 size 2-stroke
R/C engines can vary in weight from 11 oz. to 18 oz. - that’s almost a half pound difference, way out on the nose of your model!
There can even be as much as a 3/4 oz. difference in weight between different brands of propellers! So, that’s why every model
must be balanced before flying. Don’t feel that whatever the balance point your model came out at is “good enough”. Check
carefully and make whatever adjustments are required. Trying
to fly an out of balance model is dangerous!
If you are using a receiver battery pack you will also be using a
receiver on/off switch. The switch needs to be mounted in the
fuselage side, so that it can be operated from the outside of the
airplane when the wing is installed. With a glow engine it is always a good idea to mount the switch on the side away from the
engine exhaust port/muffler.
Preliminary: To balance your KADET LT-40, all of the parts and
components must be installed in their correct positions In the
model. This includes all the radio gear, the propeller, muffler (if
applicable), etc. Every piece of essential equipment must be installed, ready for flight. Always balance a glow powered model
with the fuel tank empty. Always balance an electric powered
model with the battery pack in place.
A switch location has been laser cut into the left fuselage side,
in the cabin area, underneath the covering. Use a sharp hobby
knife to trim the covering material away to open up the switch
mount. Trial fit your switch. If necessary make alterations to the
cutout to fit your switch. Then mount the switch in the fuselage
side using the screws that came with the switch.
Between 3-1/2” to 4-1/4” Behind The
Leading Edge Of The Wing
(Anywhere within this range is acceptable.)
Using a ruler, measure back from the leading edge of the wing
and mark the balance range on the bottom of the wing, next to
the fuselage. Make the same marks on both sides of the fuselage. Place your fingertips within the balance range on both
sides of the airplane and carefully lift it off the table. No part of
the model should be touching anything except your fingertips! If
the KADET LT-40 will sit on your fingertips in a level attitude, then
it is properly balanced and ready to fly.
If the airplane sits on your fingertips in an extreme nose down
attitude, then it is nose heavy. You will have to add weight to the
rear of the airplane to get it to balance. NOTE: Before adding
additional weight to the model, try simply moving the battery pack
to a further aft location. The battery pack is relatively heavy and
therefore makes a good balancing tool. You might try switching
places between the battery and receiver. If you can’t get your
Following the radio manufacturer's instructions, plug all the wires
for the servos, battery pack, and switch harness into the receiver
so the radio system is fully operational. Double check to be sure
that each servo is plugged into its correct receiver port and that
it is responding properly.
find out if there is an R/C club and flying field in your area. The
local club field is the ideal place to fly your new Kadet! Joining
the local flying club will not only give you access to a large, safe
place to fly, but you will enjoy being around all types of R/C model
airplanes and talking to their builders.
model balanced simply by re-locating the battery pack, then you
will have to purchase lead weights from your hobby dealer and
glue them into the tail end of the fuselage.
If the airplane sits on your fingertips with the tail down, it is tail
heavy. DO NOT ATTEMPT TO FLY IT! A tail heavy model is very
dangerous and will most likely crash!! Weight will have to be
added to the nose of the model to bring it into balance. The
weights can be glued to the front of the firewall; or inside the
cowling. There are also extra heavy spinner nuts available for
tail heavy models. Wherever you put the balancing weight, make
sure it cannot come loose in flight! Because the KADET LT-40
has so much wing area, adding balancing weight will have little
effect on its flying ability.
LEARNING TO FLY radio control model airplanes is not a skill
you will learn in a few minutes. It’s very similar to learning to fly
a real airplane in that you should enlist the help of an instructor
before you try to pilot the airplane yourself. A lot of things can
go wrong with R/C airplanes, and if you are not prepared to deal
with them instantly, you will loose your brand new airplane in a
crash. To practically eliminate any chance that your first flight will
end in disaster, we strongly recommend that you seek the assistance of a competent R/C pilot to help you with the first flights.
An instructor serves two purposes. First, he will take your model
up for its first test flight to make sure it is performing properly before you try to fly it. When a brand new R/C model takes off for
the first time, there is no way of knowing which way it is going to
go. Some models will try to climb, while others may want to go
down. Some will turn left, others right. Some models will be
doing both at the same time! It doesn’t mean that there is anything wrong with the model, but these minor differences must be
“trimmed out” in order for the model to fly “hands-off” straight and
level. An experienced pilot can instantly correct an out of trim
model before it crashes to the ground. An inexperienced beginner has almost no chance of saving an out of trim model!
Double check the alignment and movement of all the controls
one more time! Make sure none of the pushrods are binding or
the servos stalling. Adjust all of your pushrod linkages so that
the control surfaces are in their neutral position when the transmitter sticks and trim levers are centered. Make sure the control
surfaces move in the proper direction when you move the sticks.
You’d be amazed to know how many models have been destroyed on takeoff with one of the controls reversed. Don’t let it
happen to you! It’s a good idea to get into the habit of checking
for proper control response every time you get ready to fly.
The second reason for an instructor is to have someone there
who can correct any mistakes you make when you take over the
controls for the first time. Let the instructor get the model airborne and flying straight and level at a safe attitude (“several mistakes high” as the old saying goes) before he turns the
transmitter over to you. You will quickly find out that it is very easy
to over control an R/C model and to get disoriented - EVERYONE
DOES IT AT FIRST! If you get out of control on your first flight,
quickly hand the transmitter back to your instructor so he can
rescue the airplane. He will get it leveled off and then let you try
it again. Without an instructor, you won’t get a second chance!
Adjust your pushrod linkages and/or transmitter EPA (End Point
Adjustment) settings as necessary to provide the recommended
amount of control surface travel. NOTE: The rudder measurement is taken from the bottom of the rudder, at its widest point.
AILERONS: 3/8" UP, 3/8" DOWN
ELEVATOR: 9/16" UP, 9/16" DOWN
In addition to not over controlling, another problem beginners
need to overcome is the left/right control reversal that happens
when a model is flying towards you one minute, away from you
the next. For example, if you were seated in the cockpit of a fullscale airplane and moved the control stick to the right, the airplane would always turn to your right. Moving the control stick to
the left, the airplane would always turn to your left. Well that’s
not always true with an R/C airplane! If the model is flying away
from you, the controls are normal - right stick makes the airplane
go right, left stick makes the airplane go left. But when the model
is flying towards you, the controls are reversed - now when you
move the stick to the right, the model turns to its right, but that
means it turns to your left! This control reversal is very confusing
to all first time R/C pilots! More than a few licensed full-scale pilots have found out that flying R/C airplanes is a lot different than
flying full-scale airplanes because of this phenomenon.
❑ Be certain to range check your radio equipment according to
the manufacturer’s instructions before attempting to fly.
❑ Run your engine for the first time on the ground. A lot of
problems can be avoided if your new engine has been “broken
in” by running at least two tanks of fuel through it on a test stand
before you attempt to fly.
❑ Make sure all of the screws and bolts on your model are tight.
Double check to see that all of the servos are secure, all of the
servo control arms are screwed on firmly, all the R/C Links are
clamped shut.
❑ Charge your radio batteries before every flying session!
It’s not that learning to fly R/C is difficult, it’s just a lot different
than anything you have ever done before. Anyone can learn to
fly the KADET LT-40 if they are willing to listen and learn!
Do not try to fly your KADET LT-40 in your backyard, at the local
school yard, or in any other heavily populated area! If you have
never seen an R/C airplane of this size fly before, you probably
don’t realize how much room you really need. An area as big as
three football fields, that is free of power lines, trees, poles,
houses, and other obstructions is the minimum amount of room
that you will need. A school yard may look inviting, but it is too
close to people, buildings, and power lines.
Fly your KADET LT-40 as often as possible. After you get a few
flights under your belt with an instructor at your side, you will
begin to feel more comfortable at the controls. Soon you will be
flying “solo” with little thought of the moves required. It will just
come naturally! Don’t get discouraged if you have a minor crackup. Repair the damage and get back into the air as soon as possible.
The best place to fly your model is at a designated model airplane flying field. Ask your local hobby dealer or check online to