Your RC Companion Freewing Mig-21 80mm Manual

Build Companion:
Freewing Mig-21 80mm
Presented by:
Brad Miser
Your RC CompanionTM
yourrccompanion.com
[email protected]
Version 1.0

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Build Companion: Freewing Mig-21 80mm Copyright 2016 by Brad Miser
Contents
Build Companion: Freewing Mig-21 80mm ...................................................................... 1!
Program the Radio ........................................................................................................... 4!
Prepare the Vertical Stabilizer and Rudder...................................................................... 5!
Prepare the Rear Fuselage Section, Horizontal Stabilizer, and Elevators..................... 15!
Prepare the Rear Fuselage Section, Horizontal Stabilizer, and Elevators: Assemble
Horizontal Stabilizers and Configure Elevators................................................................ 16!
Prepare the Rear Fuselage Section, Horizontal Stabilizer, and Elevators: Add Orientation
Stripes and Protect Stabilizer Tips ................................................................................... 18!
Prepare the Wings ......................................................................................................... 20!
Prepare the Wings: Install Strobe Lights....................................................................................... 20!
Prepare the Wings: Configure Ailerons and Flaps........................................................................ 25!
Prepare the Wings: Check Retracts and Install Electric Brakes ................................................... 27!
Prepare the Wings: Cover the Strobe/Wire, Add Orientation Stripes, and Protect the Wing
Tips .................................................................................................................................. 36!
Prepare the Front Fuselage Section .............................................................................. 39!
Prepare the Front Fuselage Section: Replace Battery Connectors, Add Anti-spark
Connector, and Install Current and Voltage Sensors....................................................... 39!
Prepare the Front Fuselage Section: Remove Battery Tray and Temporarily Mount
Receiver ........................................................................................................................... 46!
Prepare the Front Fuselage Section: Test EDF and Telemetry and Calibrate the Throttle .......... 47!
Prepare the Front Fuselage Section: Install Stobe Lights............................................................. 50!
Prepare the Front Fuselage Section: Install Landing Lights ......................................................... 57!
Join the Rear Fuselage Section to the Front Fuselage Section..................................... 62!
Install the Vertical Stabilizer ........................................................................................... 68!
Install the Wings............................................................................................................. 73!

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Build Companion: Freewing Mig-21 80mm Copyright 2016 by Brad Miser
Install Fuselage and Components.................................................................................. 90!
Configure the Wires, Receiver, Sensors, and Controllers in the Battery
Compartment and Re-install the Battery Tray ..................................................... 99!
Prepare for Flight ......................................................................................................... 107!

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Build Companion: Freewing Mig-21 80mm Copyright 2016 by Brad Miser
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Build Companion: Freewing Mig-21 80mm Copyright 2016 by Brad Miser Page 1
Build Companion: Freewing Mig-21 80mm
This build companion provides information about how you can assemble the Freewing Mig-21
80mm and prepare it for flight. The steps in this document are certainly not the only way to
assemble the plane, but they will (hopefully at any rate) help you build your plane more easily
and faster than relying on just the documentation that comes with the model. If you don’t have
the model yet, this information may help you make an informed buying decision.
The build process described in this document covers the stock PNP version of the plane as it
came out of the box. Generally, the build on this model is straightforward and assuming you
have prior modeling experience (which you should before trying to build and fly this plane!), you
won’t have any trouble assembling it. When the build process is simple, you won’t find a lot of
detail in this document; your experience and the included manual will be enough. When
something requires more information, you’ll find more detailed steps.
I describe the steps to make a number of modifications to improve the maintainability,
performance, durability, or flying characteristics of the model. The details for the
upgrades/modifications are provided in separate steps that you can choose to ignore if you don’t
want to make the upgrades/modifications. The upgrades/modifications included in this build
companion are:
•Strobe lights:
ØStrobon v2 Navigation Light (Green) x 2 (right side of vertical stabilizer and bottom
of right wing)
ØStrobon v2 Navigation Light (Red) x 2 (left side of vertical stabilizer and bottom of
left wing)
ØStrobon v2 Navigation Light (White) x 1 (top of fuselage rear of the cockpit)
ØStrobon XL Navigation Strobe (Green) x1 (bottom of fuselage just behind the nose
gear wheel well)
I purchased these lights here: http://www.flytron.com/12-led-systems
•Landing lights:
ØFreewing Stinger 90 Light Controller

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ØFreewing 5W White LED Light with 1000mm Lead x 2 (left and right side of
fuselage just in front of the nose gear wheel well)
I purchased these lights here: https://www.motionrc.com/collections/led-lights
•Electric brakes:
ØJP Hobby Electric Brake System With 4.0mm Shaft - 55mm
I purchased these brakes here: http://www.rc-
castle.com/index.php?route=product/product&product_id=5409&search=JP+Hobby+
Electric+Brake+System+With+4.0mm+Shaft+-+55mm
•Orientation stripes:
ØTop Flite Trim MonoKote Neon Yellow (stripes on the bottom of the left wing and
left horizontal stabilizer)
ØTop Flite Trim MonoKote Neon Green
I purchased the trim sheets here: http://www3.towerhobbies.com/cgi-
bin/wti0095p?FVSEARCH=%3Cb%3Emono%3C%2Fb%3Ekote+trim+sheet
•Wing and horizontal tip protection:
ØMod Podge Waterbase Sealer, Glue and Finish
I purchased this glue here:
https://www.amazon.com/gp/product/B00CI1U5NQ/ref=oh_aui_detailpage_o06_s00
?ie=UTF8&psc=1
•Anti-spark Connector:
ØJeti AFC Anti-Spark Connectors 5.5mm (150A)
I purchased this connector at this website: http://www.espritmodel.com/jeti-afc-anti-
spark-connectors-5-5mm-150a.aspx
Note that the locations and types of lights and orientation stripes I added to the plane are done
solely for my own preferences and are not aligned with the full-size aircraft, i.e., these are in no
way scale modifications.

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I apply Mod Podge to areas that tend to get scuffed in handling or landing, especially the bottom
of wing tips and the bottom of the tips of the horizontal stabilizer. This glue dries clear and
leaves a hard shell on top of the foam. It won’t prevent it from breaking or getting damaged in a
rough landing, but does help protect against minor scuffs from landing or handling during
transport. Tape can be used for the same purpose, but the glue is easier to apply in these areas.
I also point out areas that were problematic on my build; I note these are the beginning of each
section with the labeled Quality Issues. Unfortunately, there tends to be a lot of variability in the
quality of models depending on the specific production process used; you may or may not
encounter the same issues I did or you may encounter others with your model that I didn’t find
on mine.
When I build, I first prepare each section of the plane all the way to setting trims and range of
motion of control surfaces (when possible) before assembling the plane as I find it easier to work
on the sections before they are assembled. It also enables me to test each servo, control surface,
etc., before the plane is assembled, making it easier to correct any problems I find. Refer to the
Table of Contents to see the overall build process used.
I use a FrSky Taranis radio for my planes because of its excellent performance, flexible and easy
programming, custom audio announcements, and telemetry. Because of the many options in
radio systems, this document does not cover radio programming or set up. If you also use a
Taranis and want to have the eepe file for this plane that I use as a baseline for yours, send an
email to [email protected].
For a video tour of the completed plane, visit:
http://www.youtube.com/watch?v=Hy7gvTCyHr8

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Build Companion: Freewing Mig-21 80mm Copyright 2016 by Brad Miser Page 4
Program the Radio
I prefer to program the radio as the first step in the build process because I can then use the
actual radio setup during assembly, such as to center servo arms, center control surfaces, adjust
control surface range of motion, etc. If you use a servo tester instead, you may find differences in
the center position and range of motion when you switch over to the radio.
I used an 8-channel receiver with this plane with the following channels:
1. Throttle
2. Ailerons
3. Elevator
4. Rudder
5. Landing gear and landing lights (lights are on any time gear is down)
6. Flaps
7. Nose gear steering and strobe lights (power only for strobe lights as they are always on)
8. Brakes
I added telemetry for battery pack voltage, cell voltage, and current. The receiver and sensors I
used are:
•FrSky X8R - 8/16 Channel Receiver
•FrSky SP-FLVS - Smart Port Lipo Voltage Sensor
•FrSky SP-150A - Smart Port 150 Amp Sensor
I purchased these items here: https://alofthobbies.com/radio-gear/frsky-telemetry-
system.html

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Prepare the Vertical Stabilizer and Rudder
I modified the vertical stabilizer by adding a red strobe light to the left side of the vertical
stabilizer and a green strobe to the right side.
Quality Issues
•Red star decal on left side of vertical stabilizer was partially covering the servo pocket
area where the servo arm moves.
If you aren’t installing the strobe lights, skip steps 2-21.

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1. Cut and lift up the star decal to clear the area through which the servo arm moves; if you
remove any parts of the decal, make sure you save them so you can repair it later. If you
are installing the lights, expose the area just in front of the servo so that you can route the
light’s wire to the channel through which the rudder servo’s wire passes. If you aren’t
installing the lights, you just need to remove enough so that the servo arm can move
freely.
2. Mark the location of strobe light. I placed mine just below the top section of the vertical
stabilizer. I wanted to mount it in the white area so I could use white trim to cover it and
the wires.

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3. Mark the route for the wire to run down the stabilizer.
4. Mark the route for the wire to run from the servo pocket to the channel through which the
servo wire runs out the bottom of the vertical stabilizer.
5. Use a hobby knife to rough cut the area in which you will mount the light.
6. Use a hobby knife to cut the channel for the light’s wire.
7. Use a Dremel tool and router bit (and router attachment if you have one) to finalize the
light mounting area.

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8. Test fit the light in the mounting hole until the top of the led base is about even with the
surface of the foam. If it isn’t, continue working on the hole until the light fits down into
the foam.

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9. Repeat the process to create the light mount area on the right side of the stabilizer; you
don’t need a wire channel on this side because you can route the wire for this side
through the stabilizer to join the wire on the other side.
10. Back on the first side, cut a channel for the wire to run past the servo and create an
opening down into the channel through which the rudder servo wire passes. You need to

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dig down through the foam a bit to reach the existing channel.
11. Run a piece of wire through the rudder servo wire channel to the area you cut for the light
wire so that you can pull the light wire down through the servo wire’s channel.
12. Solder positive and negative power wires onto each light; if you want to be able to turn

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the lights on or off, also solder a control wire to the lights. I prefer the lights always be on
when the plane is powered up so I don’t use the control wire.
13. Create a hole from the right side of the stabilizer to the left side and pass the wire from
the strobe on the right side to the left side.
14. Solder the wires from the right and left side lights to a single wire that runs down the
stabilizer; you should make this wire the same length as or a bit longer than the rudder
servo wire so it reaches to where your receiver will be mounted.
15. Use the wire puller you inserted earlier to pull the power wire into the channel through
which the rudder servo wire runs out the bottom of the stabilizer.
16. Before finalizing the installation, check the lights to make sure they work correctly.

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17. Glue the lights in position.
18. Route the power wires into the channel you made earlier.
19. Replace the decal over the area from which you removed it.

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20. Cover the wire channel with matching tape or covering; I used white MonoKote trim,
which matches nearly perfectly.
21. Cover the light with the same tape or covering (I use a hole punch for paper to create the
hole around the led).
22. Repair the star decal; I used red MonoKote trim, which was a very close match. While
the star doesn’t look quite right because part of an arm is missing, that was better for me
than trying to reposition the entire decal because that would have messed up the
underlying paint.
23. Cover the light on the other side in the same way.

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24. Install the rudder pushrod, center the rudder, attach the keeper on the pushrod, and set the
range of rudder movement per the manual.

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Prepare the Rear Fuselage Section, Horizontal Stabilizer, and
Elevators
In this section, you prepare the rear section of the fuselage by installing the horizontal stabilizers
and configuring the elevators. I modified my model by adding orientation stripes and I covered
the tips of the stabilizer and elevators with Mod Podge glue to protect against scuffs.
Quality Issues
•Servo arms not centered and no provision for accessing the arm or screw to re-center
them.

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Prepare the Rear Fuselage Section, Horizontal Stabilizer, and
Elevators: Assemble Horizontal Stabilizers and Configure Elevators
1. Attach the horizontal stabilizers to the rear section of the fuselage using the four screws
as specified in the manual.
2. Connect the elevator servos to the receiver and center all trims and subtrims.
3. If a servo arm isn’t centered as it wasn’t on my model, cut an access area so you can
reach the arm’s screw with a screwdriver; you will also need to remove foam above the
servo arm so that you can remove the arm from the servo.