Roc Hobby Critical Mass User manual

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Http://www.motionrc.com

CRITICAL MASS
OPERATING MANUAL

Read the ENTIRE instruction manual to become familiar with the features of the product WARNING:
before operating. Failure to operate the product correctly can result in damage to the product, personal
property and cause serious injury.
This is a sophisticated hobby product and NOT a toy. It must be operated with caution and common sense
and requires some basic mechanical ability. Failure to operate this Product in a safe and responsible manner
could result in injury or damage to the product or other property. This product is not intended for use by
children without direct adult supervision.
This manual contains instructions for safety, operation and maintenance. It is essential to read and follow
all the instructions and warnings in manual, prior to assembly, setup or use, in order to operate correctly
and avoid damage or serious injury.
!
Safety Precautions and Warnings
As the user of this product, you are solely responsible for operating in a manner that does not endanger
yourself and others or result in damage to the product or the property of others. This model is controlled
by a radio signal subject to interference from many sources outside your control. This interference can
cause momentary loss of control so it is advisable to always keep a safe distance in all directions around
your model, as this margin will help avoid collisions or injury.
Age Recommendation: Not for children under 14years. This is not a toy.
• Never operate your model with low transmitter batteries.
•Always operate your model in an open area away from cars, traffic or people.
• Avoid operating your model in the street where injury or damage can occur.
• Never operate the model in the street or in populated areas for any reason.
• Carefully follow the directions and warnings for this and any optional support equipment (chargers,
rechargeable battery packs, etc.) you use.
• Keep all chemicals, small parts and anything electrical out of the reach of children.
• Moisture causes damage to electronics. Avoid water exposure to all equipment not specifically designed
• Never lick or place any portion of your model in your mouth as it could cause serious injury or even death.
and protected for this purpose.
page1
WARNING
ROCHOBBY Friendly Reminder
Thank you for purchasing a RocHobby product.
Our goal is to provide high quality products and
offer great customer service. If you have any
problems with your product or want to offer
suggestions for improvements (such as plane
design, packaging, building instructions, etc.)
please feel free to contact us at
[e-mail]

page2
step1
1. The control surface horns for the elevator
are stapled to the bag containing the
elevator, do not accidentally discard them.
4. Insta l l t h e e levator con t r o l s urface
horns o n t h e b o ttom of the e l e v a tor
surfac e w i t h t he screws p r o v i ded in
the smal l p l a s tic bag.
Note: T h r e ad in the screw s f r o m t he
backpl a t e s i de.
Always m a k e s u re that the s c r e w s
are grab b i n g i n to the back p l a t e s of
the cont r o l h o rns.
It is very i m p o r tant that t h e s e p arts
are hold i n g t i ght.
2. The side of the stabilizer that contains the
slot for the carbon rod is the down side, make
sure to install the control horns on this side.
3. Make sure the control surface horns are
facing the right direction before
installing
5. Attach the rudder control horn on the
starboard (right) side of the rudder.
1
2
3
4
5.1
5.2
Install the control horns
For More Info Vist: www.motionrc.com

page3
step1-2
6. Now attach the aileron surface control
horns to the bottom of the lower
main-wing .
7. Attach the flap control surface horns,
you will need to open the flap to install
the back plate.
1. Put the Z-bend end of the linkage into
the desired servo control horn hole.
It is a tight fit and should allow the
linkage to move just slightly within the
hole to avoid binding up.
2. Snap the clevis into the surface control
horn.
3. The provided piece of fuel tubing keeps
the clevis closed during flight.
Do all the linkages the same way.
6
7
1
2
3
Install the control horns Installation of the linkage rod
For More Info Vist: www.motionrc.com

page4
step3
1. Prepare an appropriate amount of glue
for the stabilizer installation
2. Apply glue to the portion of the carbon
rod that will be inserted into the horizontal
stabilizer.
3. Insert the carbon rod into the port side
(left) stabilizer.
4. Apply glue to the remaining half of the
carbon rod and to the mating edge of the
stabilizer.
5. Apply glue on the port side of the groove
for fitting the stabilizer.
4.1
4.2
2
35
1
Install the stabilizer
For More Info Vist: www.motionrc.com

page5
step3
Install the stabilizer
6. Mount the port side stabilizer into the
groove with the carbon rod side face
down.
7. Apply glue on the other stabilizer half.
8. Turn the fuselage over so the bottom of
the stabilizer faces up. Apply glue to the
carbon rod. Then slide the carbon rod
into the grove and fully seat the stabilizer
into the fuselage tail slot.
9. Center the stabilizer as shown in the
image below.
10. Make sure the stabilizer is parallel to the
wing as shown. Adjust any misalignment
before the glue dries thoroughly.
AA
BB
A=A
B=B
10
6
79
8.1
8.2
For More Info Vist: www.motionrc.com

page6
step4
Mount the main wing to the fuselage
1. Remove the battery hatch by lifting the
cover from the rear end. The Hatch cover
attaches to the fuselage using four
magnets.
2. Position the wing so the main wing fits into
the wing bay. Guide the cables through the
hole on the bottom of the fuselage. Put the
wing in place and at the same time, gently
pull the servo cables from inside the canopy
to avoid any tangling of cables.
3. Attach the main wing using four pieces
of the provided self tapping screws.
Two screws are used for the rear wing
bolt washers (PA2.6X35 2PCS ), two for
the front wing washers.
( PA2.6X50 2PCS)
1
2.1
2.2
3.1
3.2 PA2.6X 50 2PCS
PA2.6X 35 2PCS
For More Info Vist: www.motionrc.com

page7
step5
1. Locate the battery in front of the hatch
cover bay.
2. The nose on the hatch cover will hold the
battery in position.
Wire connection diagram
Note: All servo and retract leads have been specifically labeled for your convenience.
Use the provided Y-harness for situations where two servos are controlled by one
channel; for example ailerons, landing gear, and flaps. Refer to the diagram above for
recommended connections.
Receiver
Throttle
Rudder
Y-harness
Aileron
Aileron
Aile
CH-1
Elevator
Elev
CH-2
Thro
CH-3
Rudd
CH-4
Landing Gear
Landing Gear
Gear
CH-5
Flap
Flap
Aux-1
CH-6
12
Wire connecting
For More Info Vist: www.motionrc.com

page8
step6
Control surface testing and setting
2. Adjust the split elevators so that they are
flush with the stabilizer.
Note: We recommend you use the clevises
to adjust the trim rather than using the
electronic trim function on your transmitter.
This will allow you full asymmetrical trim
ability while you are airborne.
3. Set the rear landing gear neutral position by
loosening the screw on control connector
and moving the linkage rod. Be sure to
tighten the screw when the adjustment is
complete.
4. Make sure the rear landing gear tire aligns
with the fuselage centerline.
1. Before getting started, bind your receiver
with your transmitter. Please refer to your
Transmitter Manual for proper operation.
CAUTION: To prevent personal injury, DO
NOT install the propeller assembly onto
the motor shaft while testing the control
surfaces .
Make sure all control sticks on your radio
are in the neutral position (rudder, elevator,
ailerons) and the throttle is in the OFF
position.
All servos have been factory set to the
neutral position. Thread the clevis on the
linkage rods for each aileron and adjust
the clevis so that the control surface aligns
with the trailing edge of the wing tip.
Note: Please secure the clevis to the control
horn when the adjustment is complete.
1.1
1.2
2
3
4
For More Info Vist: www.motionrc.com

page9
step6
5. Adjust the rudder using the same method
as the ailerons. Make sure the rudder
aligns with the fuselage centerline.
6. Adjust the two split elevator halves using
the same method as the ailerons. Make
sure the elevator halves are level with
each other.
7. Adjust the split elevators so that they are
flush with the stabilizer.
Note: We recommend you use the clevises
to adjust the trim rather than using the
electronic trim function on your transmitter.
This will allow you full asymmetrical trim
ability while you are airborne.
8. Cycle the retractable main landing gears
several times to ensure proper function.
6
8
7
5.1
5.2
Control surface testing and setting
For More Info Vist: www.motionrc.com

page10
step7
Install the propeller
4. Install the spinner middle part ensuring
it seats tight to the backplate.
5. Hand tighten the front part of the spinner
to secure the complete assembly.
CAUTION: Before testing the propeller, make sure the tail of the plane is firmly on the
ground and ensure there are no people or objects in the range of the propeller.
1. Disconnect the battery from airplane’s
Electronic Speed Control (ESC). Put the
spinner backplate onto the motor shaft,
making sure the hex nut fits properly into
the notch in the backplate.
2. Install the propeller onto the motor shaft
and fully seat on the director plate.
3. Make sure the painted side of the
propeller faces the front.
1
2
3
4
5.1
5.2
For More Info Vist: www.motionrc.com

page11
: 1100mm /43.3 in
: 918mm /36.1in
: 1090g /38.4oz
: 50mm
: 11.1V 2200mAh Li-Po Battery
: 35A
: 3536-KV750
: 24.5dm2
: 44.5g/dm2
: 6 Channel, 6 Servos
And 1 Brushless ESC
Wingspan
Length
Weight
CG Position
Battery
ESC
Motor
Wing Area
Wing Load
RC System
Specification Center Of Gravity(C.G.)
Center of Gravity
When balancing your model, adjust the motor battery as necessary so the model is level or
slightly nose down.
This the correct balance point for your model.
After the first flights, The CG position can be adjusted for your personal preference.
1. The recommended Center of Gravity(CG) location for your model is (50 )mm/3.5in
back from the leading edge of the top main wing as shown with the battery pack installed.
Mark the location of the CG on top of the wing.
2. When balancing your model, support the plane inverted at the marks made on the top
of the main wing with your fingers or a commercially available balancing stand. This is
the correct balance point for your model, Make sure the model is assembled and ready
for flight before balancing.
Note: Always balance the plane with the retracts down.
Control throw setting
1. Turn on the transmitter and receiver of your model.
check the movement of the rudder using the transmitter.
When the stick is moved right, the rudder should also move right. Reverse the direction
of the servo at the transmitter if necessary.
2. Check the movement of the elevator with the radio system.
Moving the elevator stick toward the bottom of the transmitter makes the airplane
elevator move up.
3. Check the movement of the ailerons with the radio system, moving the aileron stick right
makes the right aileron move up and left aileron move down.
4. Use a ruler to adjust the throw of the elevator, aileron and rudder.
Adjust the position of the pushrod at the control horn and the transmitter to achieve the
following measurements when moving the sticks to the end point.
Note: Always disassemble the propeller set when binding the transmitter and testing the
control surface.
Main specification
50mm
For More Info Vist: www.motionrc.com

page12
The suggested throws for the ROCHOBBY CRITICAL MASS are as follows:
High rate Low rate
Elevator - 15mm/0.6in up and down 9mm/0.04in up and down
Rudder - 15mm/0.6in left and right 9mm/0.04in left and right
Ailerons - 28mm/0.7in up and down 17mm/0.7in up and down
Flaps - Mid 22mm/1.2in
Full 30.5mm/1.2in
Main specification and spare parts
Item#
Description
Spare parts list for silver scheme
KT-101 Fuselage
KT-102 Main wing
KT-103 Elevator (One set)
KT-104 Cowl
KT-105 Servo hatch cover
KT-106 Canopy (One pc plastic canopy)
KT-107 Propeller
KT-108 Spinner
KT-109 Main landing gear (One set)
KT-110 Linkage rod (One set linkage rod)
KT-111 Main landing gear assembly (One set)
KT-112 9 g servo
KT-113 Retract (One pc for main landing gear)
KT-114 Motor (3536-KV750)
KT-115 ESC (35A)
KT-116 Battery (11.1V, 2200mAh, 25c)
KT-117 Motor Board
KT-118 Motor Base
KT-119 Motor Shaft
KT-120 Sticker (One set sticker)
For More Info Vist: www.motionrc.com

page13
Spare Parts List
KT-101 KT-102 KT-103 KT-104
KT-105
KT-113
KT-117
KT-109
KT-114
KT-118
KT-106
KT-110
KT-115
KT-119
KT-107
KT-111
KT-116
KT-120
KT-108
KT-112
For More Info Vist: www.motionrc.com

page14
Extra propeller noise
or extra Vibration.
Reduced flight time or
aircraft underpowered.
Control surface does
not move, or is slow to
respond to control
inputs.
Control reversed.
Motor loses power.
Motor power pulses
then motor loses power.
LED on receiver
flashes slowly.
Damaged spinner, propeller.
motor or motor mount.
Loose propeller and spinner
parts.
Propellor installed backwards.
Flight battery charge is low.
Propeller installed backward.
Flight battery damaged.
Control surface, control horn,
linkage or servo damage, Wire
damaged or connections loose.
Channels need be reversed
in the transmitter.
Damage to motor, or battery.
Loss of power to aircraft.
ESC uses default soft Low
Voltage Cutoff(LVC).
Power lose to receiver.
Aircraft will not
respond to the
throttle but responds
to other controls.
ESC is not armed.
Throttle channel is reversed.
Lower throttle stick and throttle
trim to lowest settings.
Reverse throttle channel on
transmitter.
Replaced damaged parts.
Tighten parts for propeller
adapter, propeller and spinner.
Remove and install propeller
correctly.Completely recharge
Flight battery.
Replace flight battery
and obey flight battery
instructions.
Replace or repair damaged
parts and adjust controls.
Do a check of connections for
loose wiring.
Do the Control Direction Test
and adjust controls
for aircraft and transmitter.
Do a check of batteries,
transmitter, receiver, ESC,
motor and wiring for damage
(replace as needed).
Land aircraft immediately and
Recharge flight battery.
Check connection from ESC to
receiver.
Check servos for damage.
Check linkages for binding.
Possible Cause Solution
Problem
Battery Selection and Installation.
1. We recommend the 11.1V 2200mAh 25C Li-Po battery.
2. If using another battery, the battery must be at least a 11.1V 2200mAh 25C battery.
3. Your battery should be approximately the same capacity ,dimension and weight as the
11.1V 2200mAh 25C Li-Po battery to fit in the fuselage without changing the center of gravity
a large amount.
Troubleshooting
For More Info Vist: www.motionrc.com

Range Check Your Radio System
After final assembly, range check the radio system with the ROCHOBBY CRITICAL MASS.
your
Refer to specific transmitter instruction manual for range test information .
12. Find a safe and open area.
2.Charge fl ight battery.
3.Read this instruction manual thoroughly.
4.Fully assemble model.
5.Install the flight battery in the aircraft ( once it has been fully charged ).
6.Bind aircraft to your transmitter.
7.Make sure linkages move freely.
9.Perform the Control Direction Test with the transmitter.
10. Adjust fllight controls and transmitter.
11. Perform a radio system Range Check.
1. Remove and inspect contents.
8. Make sure the rubber ring has been properly installed on the clevis.
First Flight Preparation
Take off and landing tips
Please read the following instructions and fully understand it.
3. Children under the age of 12 should have an adult guide. Never recommend for the children
under the age of 14.
4. Never leave the charger in wet conditions.
5. The CRITICAL MASS is made from PA and polythene which are tinder. When it meets
the heat,
transfiguration can easily happen, so you must keep it away from heat.
6. Do not attempt to catch the while flying, please do not touch the propeller.CRITICAL MASS
7. Never leave this system unattended around children with battery in the unit, as injury may be
caused due to children's turning on the transmitter or the plane.
8. During the preparation for the flight, please remember to turn on the transmitter before
connecting the battery pack.
9. Close the throttle on the transmitter before connecting battery otherwise the motor may operate.
1. Do not fly in strong wind or bad weather.
2. Never fly the model in crowded areas, where there are lots of people, automoblies on the
road or power lines overhead . Also do not to fly around the airport. Please make yourself
enough room for the flying and operating, as the plane can travel at high speed. Remember
you are responsible for the safety of others.
1. Take off using full power, as soon as you have taken off retract the landing gear.
2. Use the flaps to give a steeper landing approach, increase throttle slightly to offset the
increased drag.
3. Ensure that you set a timer and land with plenty of battery power in reserve.
4. It is difficult to land the plane perfectly from a high speed flight when the flaps are in the
up position.
5. Never exceed 3 minutes of continuous full power flight.
6. Never exceed the limited flying weight.
Flying Tips
page15
For More Info Vist: www.motionrc.com

page16
AMA
AMA
If you are not already a member of the AMA, please join, The AMA is the governing body
of model aviation and membership provided liability insurance coverage, protects
modelers’ rights and interests and is required to fly at most R/C sites.
Academy of Model Aeronautics
5151 East Memorial Drive
Muncie, IN 47302-9252
Ph.[phone]
Fax[phone]
Or via the Internet at: http//www.modelaircraft.org
A. GENERAL: A model aircraft is a non-human-carrying aircraft capable of sustained
flight in the atmosphere. It may not exceed limitations of this code and is intended
exclusively for sport, recreation and/or competition.
All model flights must be conducted in accordance with this safety code and any
additional rules specific to the flying site.
1. Model aircraft will not be flown:
(a) In a careless or reckless manner.
(b) At a location where model aircraft activities are prohibited.
2. Model aircraft pilots will:
(a) Yield the right of way to all man carrying aircraft.
(b) See and avoid all aircraft and a spotter must be used when appropriate.
(AMA Document #540-D-See and Avoid Guidance.)
(c) Not fly higher than approximately 400 feet above ground level within three (3) miles
of an airport, without notifying the airport operator.
(d) Not interfere with operations and traffic patterns at any airport, heliport or seaplane
base except where there is a mixed use agreement.
(e) Ensure the aircraft is identified with the name and address or AMA number of the
owner on the inside or affixed to the outside of the model aircraft.
(This does not apply to model aircraft flown indoors).
( f ) Not operate aircraft with metal-blade propellers or with gaseous boosts except for
helicopters operated under the provisions of AMA Document #555.
(g ) Not operate model aircraft while under the influence of alcohol or while using any
drug which could adversely affect the pilot’s ability to safely control the model.
(h ) Not operate model aircraft carrying pyrotechnic devices which explode or burn,
or any device which propels a projectile or drops any object that creates a hazard
to persons or property.
Academy of Model Aeronautics National Model Aircraft Safety Code
Effective January 1, 2011
For More Info Vist: www.motionrc.com

page17
AMA
Exceptions:
◆ Free Flight fuses or devices that burn producing smoke and are securely attached to
the model aircraft during flight.
◆ Officially designated AMA Air Show Teams (AST) are authorized to use devices and
practices as defined within the Team AMA Program Document (AMA Document #718).
3. Model aircraft will not be flown in AMA sanctioned events, air shows or model
demonstrations unless:
(a) The aircraft, control system and pilot skills have successfully demonstrated all
maneuvers intended or anticipated prior to the specific event.
(b) An inexperienced pilot is assisted by an experienced pilot.
4. When and where required by rule, helmets must be properly worn and fastened.
They must be OSHA, DOT, ANSI, SNELL or NOCSAE approved or comply with
comparable standards.
B. RADIO CONTROL (RC)
1. All pilots shall avoid flying directly over unprotected people, vessels, vehicles or
structures and shall avoid endangerment of life and property of others.
2. A successful radio equipment ground-range check in accordance with manufacturer’s
recommendations will be completed before the first flight of a new or repaired model
aircraft.
3. RC model aircraft must use the radio-control frequencies currently allowed by the
Federal Communications Commission (FCC). Only individuals properly licensed by
the FCC are authorized to operate equipment on Amateur Band frequencies.
4. RC model aircraft will not operate within three (3) miles of any pre-existing flying site
without a frequency-management agreement (AMA Documents #922-Testing for RF
Interference; #923- Frequency Management Agreement)
5. With the exception of events flown under official AMA Competition Regulations,
excluding takeoff and landing, no powered model may be flown outdoors closer than
25 feet to any individual, except for the pilot and the pilot's helper(s) located at the
flight line.
6. Under no circumstances may a pilot or other person touch a model aircraft in flight
while it is still under power, except to divert it from striking an individual.
This does not apply to model aircraft flown indoors.
7. RC night flying requires a lighting system providing the pilot with a clear view of the
model’s attitude and orientation at all times.
8. The pilot of a RC model aircraft shall:
(a) Maintain control during the entire flight, maintaining visual contact without
enhancement other than by corrective lenses prescribed for the pilot.
(b) Fly using the assistance of a camera or First-Person View (FPV) only in accordance
with the procedures outlined in AMA Document #550.
C. FREE FLIGHT
1. Must be at least 100 feet downwind of spectators and automobile parking when the
model aircraft is launched.
2. Launch area must be clear of all individuals except mechanics, officials, and other fliers.
3. An effective device will be used to extinguish any fuse on the model aircraft after the
fuse has completed its function.
For More Info Vist: www.motionrc.com