Fly-Sky Configuration
and Helicopter Setup Manual

Glossary of Terms

3D / Idle Up

Throttle and Pitch Curve setting that provides higher motor speed, and full range Plus and Minus pitch.

Aileron

This term originated from fixed wing aircraft.

For the Helicopter application it performs the same function as the fixed wing aircraft in that it will create more lift on one side of the helicopter, and less lift on the opposite side. This is accomplished by inducing positive blade pitch on one side, and negative pitch on the other side. As the blade rotates from one side of the helicopter to the other side, it will change its pitch based on the swash plate orientation. Consider this effect for a moment. The blade grips are constantly changing their angle as they rotate around the head. In slow motion you would see a washing machine effect as the blade grips rotate back and forth on the feathering shaft as it takes a roller coaster ride around the swash plate.

ARF – Assembly Required to Fly

This is a kit model that need to be assembled. In reality, all models include the Ready To Fly (RFT) require that you take it apart and reassemble with blue Locktite before flying. NEVER trust someone else to assemble your helicopter unless they have a trusted reputation. Do not trust an unknown factory assembly line worker to assemble a safe and reliable helicopter. It is your investment, and your own physical well being at risk.

Auto Rotation

The purpose of the auto rotation feature is to allow the main blades and tail blades to continue to rotate when the main drive motor stops or slows down. This feature allows the pilot a brief amount of time to land the helicopter after losing main power. After losing power, the pilot applies UP right stick to place the helicopter in to a forward and down glide path, and continue to control slight positive pitch with the left stick. Too much pitch, and the blades will stall (slow down) and the helicopter will fall out of the sky. As the helicopter approaches the ground, the pilot will perform a flare maneuver by pulling back on the stick to level or slightly nose up, and apply additional left stick (collective pitch) to gently setting the helicopter to the ground.

The way auto rotation is achieved is through the use of a One Way Bearing installed between the main gear and the auto rotation gear. The auto rotation gear is (typically the lowest gear on the main shaft and is bolted to the main shaft (Jesus Bolt). The sole purpose of the main gear is to drive the auto rotation gear through the one-way bearing. When the motor stops, so does the main gear, however the one-way bearing allows the auto rotation gear to continue rotating.

Belt Drive

RC Helicopters have three basic tail drive systems.

• Electric Motor directly attached at the end of the tail boom

• Shaft driven (also called Torque Tube)

• Belt driven

The Belt Driven tail rotor uses a cogged belt connected between two belt pulleys whereas one pulley is driven from an Auto Rotation gear powered by the main motor, and the driven tail pulley and shaft that connects to the tail rotor blade pitch control assembly.

Blade Tracking

The action of two or more blades following each other in the same exact path, and at the same angle of attack. Many factors effect blade tracking.

• Blade rigidity ( both blades should have the same flexing characteristics under the same load)

• Blade Balance - each blade weighing the same, and the weight is distributed across the blade

• Individual Blade Pitch at the same location in the blade path

• Blade leading edge contour. A blade with chips or missing material on the leading edge will effect the aerodynamics of the blade.

Always use the same matches type of blades. In other words, do not mix different blade manufacturers. Use the same part number for each blade mounted to the helicopter.

Verify the weight of the blades match using a blade balancing tool. For larger blades (especially greater than 335mm) insure the blades are balanced in the same spot between the blade grip mount and the tip of the blade.

Blade tracking is correct when you see a single fine tip of the end of the blades under high speed blade rotation.

CCPM - Cyclic Collective Pitch Mixing

Coaxial

The common use of term Coaxial as it is applied to the RC helicopter is in reference to the blade configuration. A Coaxial configuration uses two sets of blades rotation in opposite directions. The bottom set of blades are controlled by a swashplate supplying pitch and speed. The top set of blades are used to counter the centrifugal force of the lower blades, and provide turning capability. The controller of a coaxial helicopter will increase or decrease the speed of the lower and upper set of blades to provide turning without the need for a tail rudder.

Configuration File

A 67 byte binary file used by the FS-CT6A radio to store settings to an electronic computer media such as a hard-drive.

Curve

A curve is a mathematical SIN calculation between 3 or more points. The RC helicopter radio provides a number of Throttle and Pitch curves based on 5 or more reference points. The purpose of the calculation is to provide a smooth transition between the reference points. Curves are based on two variable axes. For example the Throttle curve is represented with a vertical axes of motor speed, and the horizontal axes represents the joy stick input position.

Cyclic

Represents a group, whereas each member of the group can affect a common element. In the RC helicopter terminology, the cyclic references two or more servos (typically three) that control the swash plate. Input is sent from the radio to each of the of servos in the cyclic group at a high frequency rate at the same time. As a group, the servos control the swash plate orientation thereby affecting blade pitch throughout the 360 degrees of rotation. The Tail servo is not a part of the Cyclic Servo group.

DR - double ratio controls CH1, CH2, CH4 response rates

Elevator

One of the Cyclic Servos controls the center point of the swash plate. This is the swash plate linkage centerline with the main shaft. Either directly in front of or behind the main shaft.

Fig 22

End Point

Controls Servo Travel limits. A typical servo can travel -30 degrees and +30 degrees from center for a total of 60 degrees of travel. Setting the End Point value will reduce the degrees the servo can travel.

ESC - Electronic Speed Controller

Responsible for receiving throttle input signal from the receiver, and controlling the current to the motor. Most ESC units also have a built in BEC that supplies regulated DC battery power to the receivers and all devices connected to the receiver. If the ESC does not have a built in BEC, the receiver will require an external BEC and battery pack.

The ESC should be sized according to the motor it will control. Motors have amp ratings as do the ESC. It is advised to use an ESC that has a higher AMP rating than the motor.

The ESC can become very hot in operation. If the unit gets too hot, it can damage components and result in losing all motor and servo control. If this happens in flight, the helicopter will crash. For this reason, many hobbyists chose to use an external BEC so they can retain servo control in the event of an ESC failure.

Helicopter ESC devices come with a variety of features. Some provide logging, and more advanced features. The basic ESC has the following features.

• Brake ( causes the motor to rapidly stop ) Recommend to be set to Off for Helicopters.

• Battery Type is automatically detected by all modern ESC units. However you still should set it to the type of battery you are using.

• Cut Off Type – controls what the ESC will do when it reaches low battery power. For Helicopters, you want to use the Soft-Cut option. This will cause the ESC to reduce power to the motor gently as it reaches a low battery power level. You will notice that it takes more throttle stick input to maintain flight. Quickly land the helicopter under this condition. Determine the amount of time you have been flying, and in the future, try not to reach this condition by monitoring your flight time.

• Start Mode – controls how fast the motor will spin up from a dead stop. For Helicopter models, select the softest possible setting.

• Timing Mode – is based on the motor. Typically the Low setting is used for todays electric motors, however better performance can be achieved by using the timing for your motor. Check with the motor manufacturer for the correct timing to use.

*Note - many ESC devices have become damaged using the Medium timing setting with the wrong motor. Only use the Medium timing if your motor specifies its use. The Timing is similar to a car distributor. It will excite the correct windings in the correct order at the right time. Check with your motor manufacturer for the correct timing.

• Governor Mode limits the maximum amount of power sent to the motor. Typically this setting is turned off.

Feathering Shaft & Dampeners

Also called the Horizontal Shaft. The Blade Grips connect to the feathering shaft. The feathering shaft runs through the main head and sits inside of rubber dampeners (sometime these are O-rings). The dampeners come in different hardness ratings. The soft dampener is the most common for general park flying and moderate 3D flying. Harder dampeners are used for extreme 3D flying. The Dampeners should be greased to prevent galling, and eventual failure. Soft dampeners transmit less stress and vibration to the main shaft and other head components.

Fixed Pitch

A helicopter is labeled a Fixed Pitch (FP) model when the blade pitch is set to a predetermined angle and the rotor speed determines the amount of lift. The faster the blades travel the more lift. Most FP models control direction (yaw and forward / reverse) by tilting the blade holders so that one of the blade's leading edge will dip down, and the other will dip up causing less lift on one side, and more lift on the opposite side.

Fly Bar

The Fly Bar on the Bell & Heller head assembly is an integral part of the pitch control. Do not attempt to fly your helicopter without the fly bar attached and properly adjusted.

The swashplate does not directly control the main blade pitch. Instead, the swashplate controls the Fly Bar control arms, and fly bar carriage. The fly bar is a canceling device. It slows down the reaction of the swashplate input to smooth out the input request. The fly bar will attempt to maintain its current direction of travel. When input is applied it will begin to adjust to the requested position thereby soothing the change. The more weight that is added to the ends of the fly bar result in smoother (or less responsive) transitions from the control input. As the pilot advances their skill level and want to work in more extreme 3D maneuvers, they will move the weights closer to the main shaft, or remove them entirely. Fly bar paddles are rated in weight. The Extreme 3D pilot will use very light weight and rigid fly bar paddles such as Carbon Fiber versions. The purpose is to eliminate as much weight as possible (to a limit) for extreme 3D flight.

The fly bar setup is correct when:

• The paddles are the same size and weight, with the same length and leading edge contour.

• Are exactly the same distance from the main shaft.

• Weights are the same, and exactly positioned the same distance from the main shaft.

• The fly bar moves freely up and down. Link balls with too much resistance will hamper the operation of the fly bar assembly. If they are too tight, use a link ball tool to remove burs and excess material from the plastic ball socket to provide the fly bar free movement.

Gain

The Gyro uses a voltage gain to increase or reduce the sensitivity of the gyro to lateral movement in Head Holding Mode. Too much gain will result in the tail rapidly wagging from side to side. Too little gain and the tail will wag slowly from side to side, or fall out of Head Holding mode.

The rule of thumb is to adjust the gain until you obtain a rapid tail wag, then reduce the gain until it stops wagging then reduce the gain by an additional 5~10 %.

Gyro

A device that is placed between the receiver input, and the tail servo. Its purpose is to assist the pilot in maintaining a steady tail position in flight. In Head Holding Mode, the gyro will remember its last “Non” input position, and attempt to bring the tail back to that position if something such as wind has cause the tail to move off of position.

Rate mode is similar to HH mode in that it will counter external forces such as wind, and try to keep the tail in one position. Rate mode does not have the previous position memorized and will only provide servo adjustment based on the amount of external force movement detected. After countering the external force movement, rate mode will return the servo back to its (servo) center position which may not be the original tail position.

You can determine if the gyro is in HH mode by moving the tail, and the tail slider will move to one side compensate, and it will stay in that position until the tail is returned to the original position. In Rate mode, you will notice the tail slider will move to compensate, but once you stop moving the tail, it will return to center even though the tail is not back in the original position.

Jesus Bolt

There are two Jesus bolts on a main shaft. One at the top and one at the bottom. The top bolt holds on the Head assembly, and the bottom bolt holds the Gear assembly. The term “Jesus bolt” came from the last words spoken by the pilot before the helicopter crashes due to a Jesus bolt failure.

Lift

In layman's terms the leading edge of the air foil (the blade) is contoured to produce a small amount of drag over the blade as what is occurring under the blade. This causes the blade to have more pressure under the blade. As the blade changes its angle of attack (Pitch) the pressure increases under the blade causing the blade to move away from that pressure. A positive blade pitch will produce more pressure on the bottom side of the blade lifting the helicopter upwards.

Locktite

A chemical compound that bonds to the material is is applied to fill the non tensioned space between threads on a screw. The filling of the thread space reduces the potential for vibrations to release the spring tension of the threads thereby maintaining the original torque applied to the threads.

It is recommended to use the Blue Locktite compound on all metal to metal screws. Blue Locktite has a

lower heat tolerance than Red Locktite. This allows hobbyists to use a small amount of heat on a screw treated with Blue Locktite to break down the bonding capacity of the compound and extract the screw.

Use of a soldering iron for 10 ~15 seconds on the thread tension area is enough to break down the compound and allow for screw extraction.

*Note – Never let Locktite come in contact with plastic parts. The compound will weaken the plastic as it bonds. Locktite can also scar carbon fiber materials if it is allowed to bond and harden on the carbon fiber material.

Main Shaft

The vertical shaft that is attached to a drive gear on one end, and the Rotating head assembly on the other end. Main shafts can be purchased in different metal densities. The harder shafts usually have a higher carbon composition, and are heavier. Soft main shafts bend easier than the harder shafts. The harder shafts do not flex as much as the soft shaft, therefore the harder shafts provide very accurate head spin. The down side of the harder shafts is they weigh more, and are less forgiving in a crash. Some hobbyists believe it is better to use a soft main shaft, and let it bend in a crash and possibly save other more expensive components.

Mixing

Provides the ability to assign a switch or another channel input to influence the signal on another channel. Typically used in the FS-CT6A radio to assign the Gyro Gain VR(B) dial to channel 5.

Fig 23

Mixing Control Arms

There are four mixing arm controls on a Bell Heller configuration (Fig. 23). The two at the lower section translate swash plate input through the Washout arms to the Washout Mixing Control Arms then to the Fly bar Control Arms which rotate the fly bar paddle pitch.

The upper set of mixing arms translate swash plate input through long links to the Fly bar mixing control arms that are then connected to the Main Blade Grips.

Pitch

The angle of leading edge of an air foil (the blade). Neutral or zero pitch provides no lifting capability. As the pitch angle increases, the air pressure on one side of the blade surface increases to produce Lift (see Lift above) or lateral movement (for tail blades).

Pitch Curve

A pitch curve is a set of 5 or more points measured at equal distances for the full travel of the input device (the joy stick). The Radio will calculate the signal strength between each reference point.

Pitch Gauge

A tool used to measure the blade angle from a reference level (the fly bar).

Radio Binding

The process of connecting the radio identification signal with the receiver in wireless applications.

Receiver

Wireless Electronic radio component that receives signals from a radio frequency transmitter. Signals are distributed to separate channels of the receiver to control other electronic devices.

Reverse – Servo direction settings

The configuration option to reverse the polarity of the input signal to an electronic device such as a servo.

Rod Linkage

A mechanical component consisting of one or more connector points that is used to transmit torque and direction between to points. Make sure you have the same number of threads showing on each end.

Fig 24

As a minimum, you want 5 or more threads (turns) screwed into each plastic ball link end. Figure 24 shows an link rod that should be adjusted. The easiest way of adjusting the link is to use a set of needle-nose pliers to rotate the rods at the non-threaded center portion of the rod. You can make this adjustment with the rod installed on the helicopter.

RTF – Ready To Fly

A packaged model claimed to be ready to fly out of the box. This is a myth. Always check every fastener for tightness, proper assembly and alignment, and that all metal to metal fasteners have the proper amount of Blue Locktite applied. Check that all linkages and bearings move smoothly, and there is no binding anywhere. I have experienced Locktite in bearings, missing screws, loose screws, and missing parts on both kits and RTF models. There have been many new hobbyist who actually slap a battery into their new model, and man the controls only to find out that their RTF model became Ready To Fix, or Refuses To Fly out of the box.

Rudder

A mechanical device that is used to steer or change the rear position of a movable object. Helicopters use a variable speed and typically variable pitch set of blades to provide lateral tail movement by varying the speed and pitch or direction of the tail blades.

Serial Port

Computer In/Out port used to communicate with external devices. Two way communications are provided through a serial protocol (one byte at a time).

Servo

Electronic device that takes a digital or analog signal and convert it so mechanical movement.

Servo Binding

Servo binding occurs when the servo movement is stopped before the requested servo position request has been completed. Servo binding can result in damaged servo gears, overheating of servo electronics, and servo failure.

Servo Horn

A mechanical connection between the servo output and the linkage that it controls. There are four basic servo inner hub configurations measured by number of splines and diameter. The servo horn may be a lever design or a circular design. The purpose of the device is to transfer rotating movement to a linear movement for controlling linkage.

Sub Trim

Provides small incremental adjustments to the signal level to a servo. It will cause the servo position to change by small degrees.

Swash Afr

Used to adjust swash plate travel up and down and direction.

Swash Plate

The intermediate control device whose level is transmitted to the fly bar for controlling pitch and yaw of a helicopter.

Tail Slider Control

A mechanical device that is connected by a rod linkage to the tail servo and tail rotor grips. Its purpose is to change the tail rotor blade pitch to produce lateral thrust.

Test Stand

A tool that allows for mounting the helicopter for testing under power without the potential for crashing. Some test stands provide vertical movement for safely test hovering the aircraft.

Throttle Curve

A throttle curve is a set of 5 or more points measured at equal distances for the full travel of the input device (the joy stick). The Radio will calculate the signal strength between each reference point.

Torque Tube / Shaft Drive

A Shaft driven also called a Torque Tube driven tail rudder uses a shaft to power the tail rotor blades. The advantages of a shaft driven tali rotor is smoother operation with less noise. The down side of this type of drive system is the cost for replacement parts.

Washout Arms

Fig 25

The washout assembly (or lower mixer) is a set of linkages in the rotor head that serve to mix out collective pitch inputs from the swashplate, and pass the remaining cyclic pitch inputs to the flybar control arm.

The washout assembly consists of three parts:

The washout guide (often also the phase ring) that keeps the washout aligned with the rotor head;

The washout arms that connect the swashplate to the flybar control arm linkages;

The washout base to which the washout arms are mounted, and which slides up and down the main mast.

The washout also often serves to rotate the cam follower of the swashplate with the rotor head.

A few helicopters do not have a traditional washout, and either transmit collective inputs to the rotor head via a push rod separate from the swashplate (such as the Falcon 3D), or use a flybar that can move up and down inside a guide (such as the Gazur Mars).

Washout also refers to changing blade pitch or profile along the length of a rotor blade, as the tip of the blade is moving much faster than the root. Typically model helicopter blades don't have this type of washout, as the blades are symmetrical to allow for inverted flight.

Yaw

Fig 26

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