3_Puesta a punto del Belt CP en Inglés

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How to set up a Belt CP A guide for beginners (and others)Version 1.08 - February 3, 2009

Author Ian Turner (Heliguy handle CHOPPERADDICT)

CONTENTS1.0 The legal bit

1.1 - Introduction2 Opened the box here we go3 The electrical and electronic bits4 Setting up the helicopter overview and description

5 Balancing the rotor blades5.1 - All about the rotor blades

5.2 - Getting the Centre of Gravity (COG) of each blade to match5.3 - Balancing the rotor blades together to get a perfectly matched pair.

6 Setting up the aircraft mechanically6.1 - The Servos6.2 - Connecting the LIPO for the first time6.3 - Setting up the full throttle range6.4 - Setting up the initial position of the servo horns6.5 - Setting up the position of the swash plate6.6 - Setting up the Rudder Servo

6.7 - Fitting the rotor blades to the rotor head6.8 - Setting the rotor blade pitch range correctly

6.9 - Setting up the tail drive belt tension6.10 - Balancing the fly bar and paddles6.11 - Setting the rotor blade tracking

7 Setting the aircrafts Centre of Gravity8 Information on what is necessary to replace certain common parts, orupgrade with non stock parts.

9 Summary10 Some common problems and how to resolve them.

1.0 - The legal bitThis document is provided as is, and neither the author(s), the publishers, the hostingweb site or any other person or persons involved with it in any way will accept anyresponsibility for how it is used, or any accidents or damage that may occur through youuse of the information contained herein. It is provided as a free service, and containsinformation gathered from several different source and from many years of experienceperforming the tasks described herein, but you are totally responsible for how you use itand any results of that usage.

Please note : Although this document has been placed in to the public realm by theauthor, and may therefore be downloaded and printed or stored for later reference by


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any individual who wishes to do so, it may not be used for any commercial purpose orredistributed for any sort of financial gain or be included in whole or part as a part of anyother product or products or as a part of any other documentation without the express

written permission of the author.

The author also fully acknowledges the suggestions and ideas of other interested partiesthat have been included in this document in whole or part.

1.1 - INTRODUCTION

This article is designed to be a step by step guide for anyone that has probably not setup a radio controlled helicopter before, or has tried to do so without detailed instructionssuch as these. This is because most R/C Helicopters available today are eitherJapanese or most likely Chinese sourced and manufactured, and unsurprisingly I

suppose, as my Chinese is certainly pretty damn poor, the manual written by theChinese and translated into English are equally poor. (In fact, I am told that even theChinese version isnt much better, but its what you get for your pennies.

In particular, this document is designed to show you how to setup the standard Belt-CPV1.0 (Collective Pitch) helicopter produced by ESKY in China, although in truth much ofthe general information provided in here will apply equally to most Collective Pitch (CP)helicopters.

Some areas may also be useful for those setting up Fixed Pitch helicopters as well, but itis designed and aimed at Collective Pitch helicopters (CP)

Because SAFETY is so important, I have purposefully coloured all safety warnings inRED, so please make sure you take note of them for your own and other peoplessafety. You will notice quite a lot of RED in this documentation, it is there to keep youtotally safe, so PLEASE TAKE NOTE OF EACH ONE OF THEM until you have gottotally into the SAFETY HABIT when working on R/C Helicopters.

Equally I have coloured all of the mentions of technical names in BLUE where they aredescribed so that you can find them more easily while you are learning all of thehelicopter jargon. You will find that you will very soon get used to most of these terms.

Hints and tips are coloured in green, and other points of possible interest appear inorange

If some parts appear to be rather too basic for you individually, please do bear with me,or skip down to the next section, as I am trying to target as wide a range of pilots andpotential pilots as possible. I am also assuming the standard RTF system that includesthe ESKY 0406 35 MHz transmitter (TX) and receiver (RX), although you may have theESKY 2.4GHz system.

If you do have the 2.4GHz ESKY radio then please note that where we say turn on theTX and then the RX, it may well need to be the opposite with the 2.4Hz system CHECK YOUR MANUAL FIRST TO BE SURE, and if this is the case, do it the way themanual tells you wherever we tell you to turn on/off the TX and RX.


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NB The standard ESKY radio equipment and electronic parts such as the ESC thatalso come from ESKY are commonly known as the stock parts throughout thisdocument

Although I can understand that the size of this document may put you in fear andtrepidation of even starting with R/C helicopters, please dont let it do so, as it is writtento be very detailed in the necessary areas, so there is much of it that you may be able toskip over.

Finally in this introduction, PLEASE dont think that you are going to have to do any ofthis every time you want to fly your new helicopter you CERTAINLY DONT. It is onlyneeded before its maiden flight, or quite naturally if you have replaced any parts due toa crash or whatever that may have changed any of these crucial settings.

You will very soon find that this document will guide you step by step through theprocess of the mechanical setup of your new Belt-CP, and you will probably find that itwill only take you about an hour or so.

2 Opened the box - OK then, here we go

Its Xmas day (for me right now anyway), and I guess you have either received, or boughtyourself what is known as a Ready to Fly (RTF) BeltCP (Collective Pitch) radiocontrolled helicopter as a present.

THAT IS A REALLY GREAT PRESENT !!But it is quite probable that you have never built a radio controlled helicopter, or even

tried to fly a model helicopter before, but it is possible that you may have flown fixedwing model aircraft (Known widely as planks) before.

The first thing to think about when working on or flying any model aircraft is ALWAYSSAFETY, SAFETY and then more SAFETY. This applies especially to Helicopters.We cannot emphasise this enough, but please dont take it to mean that anything to dowith radio controlled helicopters is dangerous, it is just that we always like to work andplay with the SAFETY of ourselves and other people being the primary factor.

So, please dont panic at all the red you will see in here, its there for your own good

OK then, why are Model helicopters (and also fixed wing planes) potentially very

dangerous. ?

Because in the case of the helicopter, the main rotor blades and the fly bar paddles spinat around 2000+ RPM in flight, so if you are mathematically inclined, I feel sure youcould probably soon work out the speed of the tips of the rotor blades in flight, given therotor head speed above and the circumference of the entire pair of rotors when spinningis about 800 mm. You can quickly see that this rotor blade tip speed is very fast, andtherefore, if you or someone else were to be hit by a rotor blade, serious injury or otherdamage can be the result.

SAFETY Although this is as yet unproven, we do suggest that it really is a good ideawhenever you are going to have your radio system turned on to try to ensure that there


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are no mobile phones in the close vicinity, or if there are, ensure that at least they areturned OFF. This warning can still apply EVEN IF THEY ARE TURNED OFF. This isbecause they contact the phone network carriers all by themselves, and it is possible

that they MAY cause radio interference to 35MHz radio systems.

3 - The Electrical bits

The very first thing to be done is to get some batteries into the Transmitter (TX) and intothe aircraft. The TX you will receive is either the ESKY 35MHz 0406 or the newer ESKY2.4GhZ system. For the TX you will need 8 AA type batteries, which DO NOT usuallycome with the kit. These can be normal alkaline batteries, or you can use rechargeableAA size NiCads or similar rechargeable batteries.

As you will see later on, it is important that you know which type of radio system you

have, 35MHz or 2.4GHz.

For the aircraft, you will be using what is commonly called a LIPO battery (LithiumPolymer), which DOES come with kit, and is used to provide power for the radio, plusthe servos and the motor itself, but before it can be used it will need to be charged first.

A typical LIPO battery as used in the Belt-CP helicopter

The LIPO is quite a large rectangular battery, and has two different leads coming out ofone end of it, a thick pair and another much thinner one, both with a different type of plugon it. Your kit should also have included the standard ESKY LIPO charger, which is asmall black box with two LEDs and a lead coming out of it, plus a mains adaptor to pluginto th wall outlet.

WARNING LIPO batteries can be very dangerous. They must never ever be fullydischarged, and when being charged, it is strongly recommended that you aresomewhere around to keep an eye on them. Never ever throw them in a fire and keepthem dry at all times.


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So, lets go ahead and find the LIPO battery and the charger in your Belt-CP box andfirst of all lets take a careful look at the connector on the battery chargers charging lead,and the connector attached to the thick cables on your LIPO. The red plugs you see

fitted to the thick wires are called Deans connectors, and these are the most commontype of plug and socket used to connect LIPOs to models of all types.

The Female Deans connector The Male Deans connector

Please note that the battery has a FEMALE DEANS SOCKETwhile the charger uses a MALE DEANS SOCKET.

The other connector found on most LIPOs - used to monitor charging

The reason for this should be obvious if you think about it, it is to ensure that the batterycannot be shorted out accidently, which could happen if it had the male plug fitted to it.Please note that the two pins on each Deans connector are not parallel or alignedtogether (by design), so they can only be plugged into each other in one way. It is alsovery important to try to ensure that both pins make contact at the same time. Before youdo anything else, and before you plug the charger into the wall socket, try connectingand disconnecting the deans plugs between the battery and the charger lead a few timesuntil you get the feel for how best to do it as smoothly as possible. They are designed tobe a fairly tight fit.


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SAFETY - While you are practicing this, focus on getting BOTH PINS to connect atexactly the same time, for if they dont, it is possible that this can cause problems withmotors spinning up unexpectedly and other nasty occurrences.

Here it is, with the LIPO connected to my ESC on my Belt-CP

Finally, leave the LIPO battery connected to the charging lead (in other words, with theDeans plugs connected) and then plug the charger adaptor into a wall outlet. The smallRED LED on the charger should come ON. If it does not do so, check the wall outletand if necessary the fuse in the plug.

When the battery is connected to the charger lead the green LED should come on andcontinue to flash throughout the charging period. If both LEDS flash there is a problemwith the LIPO BATTERY DISCONNECT THE LIPO IMMEDIATELY.

If the RED LED alone flashes, it signals that the charger is in protect mode. Justdisconnect the power for three seconds or so and then try again and it should be OK.

When the LIPO is fully charged, the green LED will be lit continuously.

Ok, so far so good, that initial charging process may take up to 4 or 5 hours, so we havelots of time to look at the rest of the things we are going to need to do. Well, moretruthfully YOU are going to do

What exactly should be plugged into what in the helicopters radio receiver ?.

The following list assumes that you have the standard 35Mhz Esky Transmitter (TX) andreceiver (RX). I do not have access to a 2.4Ghz Esky system to verify those settings (asyet)


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Receiver (looking from the rear of the helicopter):Channel 1: Right front servoChannel 2: Left rear servo

Channel 3: Electronic Speed Control (ESC)Channel 4: GyroChannel 5: Open (Not used)Channel 6: Left front servo

What settings exactly should be on the Transmitter (TX) ?.

Front panel:Aileron: Reverse (up)Elevator: Normal (down)Throttle: Normal (down)Rudder: Reverse (up)

Battery BayRemove the batteries, and in the back behind them, there are some DIP style switchesthat should be set as follows :

Switches A and B down (i.e. Mode 2 setup correct for most European pilots, throttleand rudder on left stick)Switch 1 OFF (swash mix enabled)Switch 2 ON (Belt type mixing)

Now lets look at your aircraft itself in a little more detail.

Remove the pretty but delicate canopy by sliding the rubber grommets outwards on thesmall pole on which they are mounted, and it will slip off very easily by pulling itforwards. Put the canopy somewhere safe so it cannot be trodden on. !

Now depending on the person or LHS (Local hobby shop) who put the helicoptertogether to make it into an RTF kit, there will be what is commonly known as the ESCwhich is usually mounted on one or other side of the frame of the helicopter. ESC simplystands for Electronic Speed Controller, but it is a really important part of all electricmodels.

From its name you can see that this takes the place of the throttle on the engine of Nitro

based models, and its task is to handle supplying the correct voltage to the electricmotor, and also to the radio receiver (RX). Most ESCs have some form of heat sink onthem that makes them quite easily identifiable. You should be able to find it easilyenough just by tracing the wires that come from the electric motor, which is just in frontof the main rotor shaft. The other end will be connected to the ESC.


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Here is my ESC mounted on the right side of the aircraft

You will see that the ESC has leads coming out of both ends, some to connect to theLIPO battery, others go to the radio receiver (RX). Follow the wires until you find theradio receiver, which is probably mounted at the back of the main frame somewhere.

If you have a 35MHz radio system you will probably have noticed that the Radio receiver(RX) has a rather long aerial wire, usually coloured orange for some reason unknown toanyone. This is how the aircraft receives instructions from the TX, so it is important that

it is mounted the most efficient way to allow this.

Most people tend to slide it through that small opaque plastic tube that you will find in thebox, and then mount that onto the skids on one side or the other. However, the aerial ismuch longer than that, so you need to handle the rest as you cannot just cut it off.

Many people wrap it around the same tube in a spiral, which is perfectly acceptable,while others wind it up and even back down the boom support arms, which is equallyacceptable. Whatever method you choose, ensure that it cannot come loose and getfouled by the main gears, or the main rotors OR the tail rotors, or you will definitely havea VERY HEAVY LANDING known to us as a CRASH ;-)

Ok, we have briefly covered what the electrical and electronic parts of the helicopter are,so we can now move on to setting the helicopter itself up correctly.

4 - SETTING THE HELICOPTER UP MECHANICALLY

Why do we need to do this you may be asking, because you bought the helicopter as anRTF (ready to fly) kit, so surely it has been done already. Well, yes and no is the bestanswer I can give you.

Although most of the parts that are provided in an ARTF (Almost Ready To Fly) kit,which is what is normally used to create an RTF (ready to fly) kit, by adding servos andradio gear, are indeed connected and working, it is not uncommon to find some parts


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that are not correctly fixed, or even connected wrongly, so we strongly recommend thatyou check each and every screw and bolt carefully to ensure they are tight, and that allthe connecting rods between the servos and the rotor head are on securely, and are not

binding. (We will cover what binding means further on in this article). Also, as we have4-5 hours to wait for your LIPO to charge anyway, what better use could there be for thattime than to learn all about your new helicopter.

In other words, the term RTF (Ready To Fly) really only means that you do NOT have topurchase anything else, except perhaps for batteries for the TX, to be able to get thishelicopter to fly, as everything else that you will need to create a flying helicopter isprovided in the RTF kit, including radio, servos, ESC etc.

NB - IT REALLY DOES NOT MEAN THAT IT IS ACTUALLY READY TO FLY

It simply means that you have all the parts needed so that WHEN fully assembled and

CHECKED and SETUP correctly, it will be able to fly. This is crucial point to understand.

Due to this, it quickly becomes obvious that it is really is important that YOU becomefamiliar with YOUR HELICOPTER as soon as you can, so what better time than rightnow. This is because you can be certain that YOU WILL CRASH from time to time, weall do, and when that happens, it will be you that has to repair your aircraft, so it isdefinitely a good thing to know as much as you possible can about how they are puttogether, how they are set up, and how they fly, and all as soon as you possibly can.

Right now, if you have been following along, you will have your LIPO on charge, you willhave removed the helicopters canopy, found and identified the ESC, the Radio receiver(RX), and the electric motor, and your new helicopter is standing upright on a level table

or workbench.

If this is not the case WHY EVER NOT - get to it right now

OTHERWISE THATS GREAT - Lets get started.

Despite the risk of appearing to be talking down to you, which is certainly not what Iintended, I am still going to run through all the various common parts of the helicopter forcompleteness.

First of course is the main frame onto or into which everything else is fitted. In mostcases, this is made of a hard but reasonably flexible black plastic, although you can also

get complete Carbon Fibre frames for the Belt-CP. This frame needs to be strongenough to support the rest of the aircraft, and resist the tremendous forces and torquesthat all helicopters create, even real ones, especially from the rotor head and tail rotors.

You will also see two largish, black plastic gear wheels mounted horizontally and stickingout of the middle of the frame directly below the rotors and rotor head. The uppermostof these is the MAIN GEAR, and this meshes with the pinion gear on the motor to drivethe rotor head. This gear includes a special one way bearing so that the rotor blades cancontinue to spin down even when you remove power from the motor. The lower gear isthe one used to drive the tail rotor gear, which in its turn is connected to the tail rotorsusing a toothed rubber belt, and this provides all of the power and facility to control thetail of the helicopter, which is also essential.


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The swash plate and mixer arms on a Belt-CP (This is the CNC upgrade Swash plate,your will be black plastic)

Lets move upwards, and immediately above the main frame where the mainshaft comesout of the top, you will find the first part of the rotor head system. This is called SWASHPLATE and it is probably the single most important part of the helicopter in terms of

giving them the ability to fly. You will see that it is circular, has various silver connectorballs sticking out of it, and if you rotate the rotor head CLOCKWISE using the fly bar(which is the direction it turns in flight) you will see that the inner part of the swash platerotates with the rotor head, whereas the outer part, that is connected by rods to theservo arms on the frame, remains stationary. It is the swash plate that CONVERTS ALLCONTROL MOVEMENTS made by the pilot (YEP thats going to be YOU) into thecorrect movements for the main rotor blades to follow to achieve the flight attituderequired. Even REAL HELICOPTERS have a swash plate.


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A view from the top of the swash plate (This is the CNC upgrade Swash plate, yours willalmost certainly be black plastic)

You will also see that the swash plate is connected by rods going down from it to theSERVOS and servo arms (horns), which are simply small electronic motors that convertradio signals received by the RX into the appropriate movements to control thehelicopter by moving the servo arms to which the connecting rods are attached. Thesein turn are connected to the control parts of the aircraft such as the swash plate, tail rotorassembly etc. You will soon see that these rods provide the way for the servos toprovide the power to in turn raise, lower, or tilt the entire swash plate in all directions.

THIS REALLY IS THE KERNEL PIECE OF CONTROLLING HARDWARE THAT

ALLOWS A HELICOPTER TO FLY AT ALL. You will see this for real once we have theLIPO battery charged and installed in your helicopter.

Moving up a little from the swash plate you will see more connecting rods that connectfrom the inner part of the swash plate to what are called either the mixer arms or thewashout arms. These are also very important as they change the pitch of the rotorsconstantly as the head spins to maintain to correct pitch on each blade independently. Ifyou did not have these mixers, then no collective pitch helicopter would ever fly.

Finally there are more connecting rods that connect from the mixers to the rotor bladegrips and also to the flybar control arms.

What is the flybar ? It is the thin rod with two small wings (called paddles) one on eachend. On the Belt-CP it is placed above the main rotors but on other models it can alsobe found immediately underneath the main rotors.

Its purpose in life is again very important. Most real helicopters do not have a fly bar asthey have the power to handle to rotor blade pitch etc, but for models they are needed tohelp provide more power and control to the main rotor blades themselves. That is whythe flybar is mounted at right angles to the main rotor blades. It also flies using itspaddles, and together with the control inputs from the swash plate and the mixer arms itprovides the additional power needed to keep the rotor blades at the correct pitch at alltimes. (Dont forget the pitch of each rotor blade changes incrementally as the headrotates. (Actually it has to do this 2 * 2000+ times a minute = 4000+ times a minute)


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Finally on the mainshaft, we come to the rotor blades themselves. As standard, theblades are made of wood, which is why they are commonly known as woodies andthey are covered with plastic so as to be as aerodynamic as possible. Each rotor blade

is shaped from front to back as an aerofoil (just like the wings of an aeroplane). Thisshape produces the maximum lift possible.

5 - Balancing the Rotor Blades

5.1 All about the rotor blades

Throughout this document we will mention the leading edge and trailing edge of rotorblades, both main and tail rotor blades, so perhaps now is a good time to clarify exactlywhat these are, as they are very important to understand.

A helicopter rotor blade is actually nothing more than a rather thinner version of a normalaircraft wing, and has much the same profile when viewed from the end. Basically theLEADING EDGE is always more curved around than the TRAILING EDGE, which tendsto be thin, rather like the edge of a ruler that has a bevelled edge. Also, all blades havesomething called a CHORD which runs along the entire length of the blade, and this is atthe thickest point across the rotor blade, which will also always be toward the FRONT ofthe blade.

So to check for the leading edge, just see where the thickest part of the blade is acrossthe width, and that is the leading edge.

The next crucial thing is to decide which is the top of the blade. Well in helicopters these

rotor blades are simply thinner wings that are rotated by the aircraft, but they still have toadhere to all the laws of aerodynamics, and these do so to generate the lift we need tofly.

Without going into those laws, the basic thing you need to establish is which side of theblade is longer from the leading edge to the trailing edge. The longest side is always thetop as to obtain lift, any wing has to have a difference between these twomeasurements. Why, well its simple really, to generate any lift at all the air passing overthe rotor blade (or aircraft wing) has to travel further across the top, which of coursemeans it moves slower underneath the wing. Basically the difference between these twospeeds is what creates lift.

TECHNICAL ASIDE.If you are of a technical bent of mind you might well now be jumping up and down andtelling me thats total rubbish ?

Well, you are of course technically correct, so to clarify this, the real fact is that wings donot create lift upwards, they actually create a suction upwards. The higher speed of theair across the top due to the increased distance it has to travel creates a lower pressurethan the air crossing the bottom, which results in a partial vacuum on top of therotor/wing.


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Due to simple physics, most types of pressures always wants to even themselves out ifpossible, so the two different air pressure areas will always try to move towards eachother. As they cant actually do so in this case because the rotor/wing is in the way, the

high pressure underneath tries to move to the low pressure on top of the rotor/wing. Thisis of course how it generates the lift under the blade, but when you think about it, the realfact is that it is actually the suction created on the top of the rotor/wing that pulls therotor/wing upwards, and not the high pressure underneath pushing the rotor/wingupwards.

Strange but nevertheless true

5.2 Getting the Centre of Gravity (COG) of each blade to match

One of the first things we can do while our LIPO is charging is to check and ensure thatthe rotors are perfectly balanced, both for the centre of gravity (COG) of each blade and

also the overall weight of each blade against the other. If they are not balanced you willget bad vibrations, loss of lift, and possibly even cause damage to other parts of themachine, so this is another crucial part of the setup process. Due to this, you shouldalways keep your rotor blades together in pairs once you have balanced them.

A typical pair of standard ESKY rotor blades for the Belt-CP

Shown above are a pair of standard ESKY wooden rotor blades, with the tracking colourstrip in place near the tips. NB they are also lying in the correct position and way up asthey will be when attached to the helicopters rotor head you can quite easily seetherefore that they revolve clockwise.


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My head and blade grips painted both red and (in my own case) white for total clarity

Most rotor blades come with a small strip of coloured tape already stuck onto them justinside the tips. Typically one is red and the other one is blue. This tape is used to let yousee which blade is flying high or low when we come to checking and setting the rotorblade tracking. However, because rotor blades, and for that matter, rotor blade gripscan vary in weight etc, it is a very good idea to put a small dab of red paint on the bladegrip that is holding the rotor blade with the red strip on it so that you always put the sameblade back into the same grip.

The coloured tracking strips

Now, having done that, lets remove the rotor blades (if they are fitted already). Find the3mm Allen key provided in the kit that exactly fits the hex cap bolts you can see on thetop of the rotor blade grips, right at the root of the blade, and carefully unscrew both of


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them. Be careful that you do not loose the Nylock nuts that are recessed into theunderneath of the blade grip, as they usually stay put in their recess, but if they do slipout you could easily loose one or both.

The roots of both rotor blades

Now slip the blades out of the blade holders and lay them carefully on your work benchor table. To do the first part of the balancing you are going to need some form of smallrod or a knife blade or a similar tool that will let you balance each of the rotor blades onto identify the exact centre point along the LENGTH of each of the rotor blades. Auseful and easy to make tool for this is to find an old Stanley knife blade, and then cut a

small groove into a small piece of wood and simply mount the blade, sharp side up, inthat groove in the wood, which will make an ideal fulcrum for the COG balancing. Youwill also need to have a soft lead pencil available.

MY rotor blade COG balancing toolA Stanley knife blade stuck into a piece of scrap wood


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How the blades will look when fitted to the helicopter correctly

Right, take one of the blades, it doesnt matter which one, and place it on the blade withthe flatter underside of blade downwards, and carefully move it along your knife edgefrom root to tip until it just balances. Hold it there and use the pencil to mark thatbalance point on the BACK (trailing) edge of the rotor blade. Now repeat the processwith the other rotor blade. So, how do we tell if the COG is the same for both blades,which is what we are trying to achieve ?

Easy, lay them down on your work surface, underside of the rotor blades on the worksurface, and with the trailing/back edges of each blade touching each other. Ensure the

outer tips on the trailing (back) edge are in exactly the same position, and then look atyour pencil marks. Are they exactly together ? If the answer is Yes, then you are lucky,and have nothing more to do .

Note the pencil marks at the centre, and that one blade has been turned upside down toallow us to compare the positions on both blades


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If they are not exactly in the same place, we are going to need to add some weight toone or other end of one of the blades to bring its COG to the same place as the otherblade. Pick whichever of the blades you wish to be the master, and move it out of the

way.

Close up of the COG pencil marks these are dead right

Now on the other blade we need to work out where we need to add or remove a little bitof weight to make it move the COG to the same place as the master blade. This is notas difficult as you may think really. Lets assume that in our case the original COG(pencil mark) on the blade we are going to change the weight on is closer to the tip ofthe rotor blade than the root. If you think about this, it means that we want to make theCOG of this blade move the correct distance toward the root of the blade, so that meansthat on this blade the tip is currently slightly heavier than we want, so we either need toadd a little more weight on the root end, or remove some weight from the tip of thisblade.

To be honest, most people find he second option is usually the best, as it is much easierto add or remove weight from the tips than the roots, and usually more beneficial. So,how exactly are we going to do that ?

Again, this is easy. If you look back a little I mentioned that each blade will have a thinstrip of coloured tape at the tip, so we can usually use a modelling knife and cut a smallamount off that strip. I normally do this on the underside of the rotor blade at the trailingedge of the blade (dont forget the blades are mounted so that they rotate clockwise, sothe leading edge is the front edge of a clock hand, and the trailing edge is the backedge)

Take your knife, and depending on how much movement of the COG you need, carefullycut around about inch off the end of coloured strip off at the trailing edge of the blade,then wipe off the original pencil mark to avoid confusion and repeat the balance check.Keep doing this bit by bit until the balance points (COG) are the same.


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NB - Dont suddenly decide to change to the other blade unless you go too far withremoving weight on the blade you are adjusting, as it can cause confusion.

ALL DONE - GREAT STUFF !!

5.3 Balancing the rotor blades to get a perfectly matched pair.

OK, so now we have a pair of rotor blades that have exactly the same COG, which isjust what we need. The final thing we need to do with the rotor blades themselves is toensure that both of the blades are exactly the same overall weight, so that whenspinning on the rotor head, they perfectly balance each other out.

For this you really do need a blade balancer, which costs around 10, but you can do itwithout by putting a bolt through the roots of both blades and using one of the Nylock

nuts to pinch them tightly together. The blades must be checked when they aremounted exactly as they will be on the rotor head, so ensure that you have the leadingedges on different sides. If you do not have a blade balancer, you would then supporteach end of the bolt through the roots of the blades on something that has the sameheight so that they can rock on the bolt. If you are using a blade balancer, then it ismuch easier, as you simply bolt each blade onto the balancer, adhering to the samerules of direction etc.

Now, let the blades settle and stop rocking, and carefully measure the distance of thecorner tip of the trailing edge of each of the rotor blades. The aim here is to have thatdistance EXACTLY the same, which means that both blades must have exactly thesame overall weight.

PLEASE DONT FORGET THAT THIS NEEDS TO BE DONE ON A TOTAL LEVELSURFACE.

If they balance already, GREAT, your all done.

If not, we obviously need to add some weight to the lighter blade, as we cannot reallyremove any weight in this case. The next question often asked is where are we going toadd it on the rotor blade ?

Well, the answer is again pretty simple, it ABSOLUTELY MUST BE ADDED AT THECOG of the lighter rotor blade, and NOWHERE ELSE.

The reason for this becomes obvious if you actually had to reset the COG in step 1. Ifyou went ahead and added some more weight to the tip of the lighter blade, the COG ofthat blade would then move toward the tip of the rotor as well, loosing the matching onthe position of the COG on both blades.

So, we will use some form of sticky tape such as electrical tape to achieve this. If youcan, use some tape the same colour as your blades, although it doesnt really matter.Depending how far out of balance the blades are you need to add more or lessadditional weight, so the best way to do this is to wrap a piece of tape of about themaximum size you think you will need over the leading edge of the rotor, with the same


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amount of tape on either side. This will help to avoid it coming off again in flight whenthose rotors are spinning at 2000+ rpm.

I like to use thin electric tape, but I cut it along the centre line to make a nice thin strip,and then start off by wrapping it across the blade on the COG mark so that it goes overthe top of the rotor from the trailing edge to the leading edge and then across theunderside of the rotor to the trailing edge again.

Right, check the balance again

Is it right now ? - most unlikely in my experience, and the chances are good that theblade to which you have added the weight is actually heavier now. No problem, we dothe same trick as previously when we were doing the COG balancing. We use a modelknife to start cutting and removing small bits of the tape that we just added at the COGpoint, starting at the trailing edge on the underside of the rotor blade. Yet again,

RECHECK, remove a little more tape, RECHECK again and again and again..

Finally, you will have them balanced perfectly GREAT STUFF !!!

I strongly advise that you use a rubber band or similar and tie the two blades together asthey are now an inseparable pair to all intents of purposes as they have been balancedto be perfect together.

Thats all there is to balancing the rotor blades. Dont forget though that you will need todo this each and every time you change a blade for whatever the reason may be.

Put the pair of rotor blades to one side carefully as we will not need them, at least just

yet. DONT FORGET TO GET THE NYLOCK NUTS FROM THE UNDERSIDE OF THEROTOR BLADE GRIPS AND SCREW THEM ONTO THE BOLTS so they do not getlost.

6 - Setting up the aircraft mechanically.

6.1 - The Servos

What are each of the servos ?

Well, unlike fixed wing aircraft, helicopters dont have the same controls, although they

are still called the same names.

All aircraft are controlled by what are known asAilerons Control how an aircraft rolls about its centre line (roll)Elevator Controls how the nose moves up and down (pitch)Rudder Controls how the aircraft turns left and right (yaw)Throttle Controls the amount of power to be used to propel the aircraft (power)

In Helicopters, the servos have some additional tasks to perform.


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The ailerons, elevators and rudder work in much the same way as on a fixed wingaircraft in terms of making the aircraft roll, change pitch, or change yaw. The throttlehowever has to do a lot more, and this in its turn, impacts tremendously on the way that

the ailerons and elevators have to work.

Why is this ?

Well, when you change the throttle settings in a Collective Pitch Helicopter, the first andobvious thing to happen is that the speed of the rotor blades will increase or decrease.The second thing is that what is known as the collective pitch will also have to increaseor decrease proportionally.

What is collective pitch ?

Collective pitch is the way that the angle of attack of the rotor blades to the airflow

changes to control the amount of lift the aircraft will provide for any throttle setting.

The more angle of attack = more pitch = more lift.Less angle of attack = less pitch = less lift.

In fact, unlike aircraft, most helicopters are designed and setup to be able to providenegative pitch angles of down to -10 degrees and about the same value of positive pitch.So when you close the throttle completely, you dont just reduce the lift to zero, you willactually start the rotors pulling the helicopter down out of the sky.

This is really the kernel of what CCPM is all about, and it is the TX that does all thismagic for you. On the stock ESKY TX it is configured internally to provide a certain mix

of throttle and pitch that you cannot change. On computerized radio systems such asthe DX6i, DX7, the similar Futaba systems and other CCPM computerised radiosystems, you can change almost all of the settings to suit your own flying needs andstyle.

In the very simplest of terms, what CCPM does is to calculate how much pitch change isneeded when the throttle setting is changed. It then sends signals to the RX on theaircraft telling all three of the servos that connect to the swash plate to raise or lower itthe correct amount, which changes the pitch of the rotor blades the correct amount tomatch the throttle setting and provide more or less lift.

The way they do this is perhaps a mystery to many people, so I will run through it very

briefly.

There are three servos connected to the swash plate, and their BASIC FLIGHT functionsare simple and obvious.

The aileron servo on the right of the aircraft tilts the right side (only) of the swash plateup and down to create roll to the right. The other servo on the left side is actually alsoan aileron servo, and it does the same as the previous one, but only effects the left sideof the swash plate to create roll to the left. When a fixed wing aircraft performs anaileron roll, one aileron goes up, the other goes down. The same functionality is alsotrue for a helicopter, so if our left aileron servo LIFTS the left side of the swash plate, the


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right aileron servo will need to LOWER the right side of the swash plate exactly thesame amount to make it tilt evenly while still keeping the pitch at the correct level.

The other servo at the front on the right side of the aircraft is known as the pitch servo,and this is configured to control the nose up or nose down attitude of the helicopter. Itconnects to the front of the swash plate on the Belt-CP, and there is only one servo usedto do this, which is why the back of the swash plate has a protruding rod that goesthrough a guide which ensures that the outer part of the swash plate doesnt try to rotatewith the inner part.

Remember that unlike a normal aircraft, raising the nose will not cause a helicopter tostart to climb. In fact, it will simply change its attitude to a more nose up one, slow downassuming it had forward speed before, and then probably start to drop in altitude, oreven, if it has no forward speed, it will go backwards, not something you will be wantingto try just yet. That is why helicopters have a collective control in addition to the other

controls found in a normal aircraft.

The complicated bit is that it is these same three servos that are used to lift and lowerthe entire swash plate evenly to control the rotor blade pitch, but that they also have tohandle the functions of the elevator and ailerons, most often at one and the same timeas changing pitch, so you can see that they are very much involved in dual activityvirtually all of the time. Why ? Because as you increase throttle and pitch to lift off, theywill start to lift the swash plate to increase the pitch. At the same time you will be tellingthe aileron servo to apply some right roll to counter the helicopters natural tendency togo right on lift off. You may also want to lower the nose to make the aircraft start tomove forward.

If you think about this, all three servos are trying to lift the swash plate exactly the sameamount so that the pitch increases, but to make it also roll to the right a bit the rightaileron needs to lower its side of the (now rising) swash plate a little bit, and the elevatorservo, which is also lifting the swash evenly to raise the pitch suddenly has to also lowerthe (now rising) front of the swash plate to make the nose of the aircraft drop.

PICTURE - Here are the two right side servos, the left picture is the right aileron servo,the right picture is the elevator servo. Both of the servo horns are NOT yet set to beperpendicular as you can see.


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HOPEFULLY THAT LITTLE BIT OF TECHNICAL BACKGROUND HAS MADE SOMESORT OF SENSE TO YOU ?

Thats exactly what CCPM takes care of, so now you know roughly what goes on, youmay not need to bother about it again

Very well done, you are now a semi qualified helicopter builder stage 1.

To do the next part, we will need to have our TX with batteries in it, and our LIPO batteryfully charged.

6.2 Connecting the LIPO for the first time

Assuming you have now had a well earned drink from reading and digesting all of theforegoing information, 4 or 5 hours will probably have passed, so with luck your LIPO

battery should now be charged.

Whoaaaaa SLOW DOWN SLOW DOWN SLOW DOWN SLOW DOWN

SAFETY - VERY IMPORTANT BEFORE YOU DO ANYTHINGELSE AT ALL, and indeed whenever you are going to work onthe aircraft, YOU should ALWAYS DISCONNECT THE MOTORFROM THE ESC to prevent it from spinning the rotor head upeven if you do touch the throttle accidently.

Look at the motor, and you will see three wires coming from it that are individually

connected to the same coloured wire coming from the ESC with push/pull connectors.

DISCONNECT ALL THREE BY CAREFULLY BUT FIRMLY PULLING AND SLIGHTLYROTATING THESE CONNECTIONS


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OK, ONLY NOW is the aircraft safe to work on. Remember how to do this, you will needto do it again very often in the future.

Disconnect your charged LIPO from the charger and also unplug the charger from thewall outlet. REMEMBER - SAFETY FIRST

Now slide it into the battery tray with the two sets of leads sticking out of the front. Findthe male DEANS CONNECTOR that is attached to the ESC, but SAFETY FIRST -DONT PLUG THEM TOGETHER YET.

Use the Velcro tape to secure the battery into the battery tray.

6.3 - Setting up the full throttle range

This step may have already been done if your helicopter was test flown by the LHS(Local Hobby Shop) you bought it from, but if it is required it is a good idea to repeat it sothat you are sure the throttle range is set correctly. With most of the upgraded ESC andthe better ESC units you may want to purchase, the ESC needs to learn the full throttlerange provided by your particular TX. To let it do so is actually quite easy.

If you have the stock ESKY ESC (ELECTRONIC SPEED CONTROLLER) then you DONOT NEED TO DO THIS but it is perhaps still worth noting where this section is for

reading when, as I am sure you will eventually decide to upgrade to a better ESC, whichmostly do need this Throttle setup to be done FIRST AND FOREMOST. So for nowthose with the stock ESKY esc can move straight on to section 6.4 if you wish to bypassthis for now.

Most decent ESCs that you can, and probably will purchase in time, do require thisthrottle setup, so please also bear in mind that if you change your TX to a different onewith an ESC that does need this, or even change the ESC, you MUST DO IT AGAINwith the new TX or ESC.

To check whether your ESC needs this setup, look in your manual, or check thedocumentation that comes with the ESC.


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SAFETY TURN THE TX OFF

Place the TX somewhere close to you so that you can reach it easily

Check that ALL of the small trim adjusters to the left and under the control levers areexactly in the centre of their sliders INCLUDING the throttle trim adjuster.

NB Yes I know that many people will tell you to move it fully down, as even do someinstruction manuals, but in fact this will mess with your power curves. For moreinformation on this if you are still not persuaded is to Google for - Finless Bobs and gothrough his posts on ESC setups.

Finally, and only when you are doing this operation, move the throttle lever which is thelever on the left (for the normal mode 2 TX used in Europe and the UK, or right hand

lever if you are flying a mode 1 TX) ALL THE WAY TO THE TOP

Dont forget that if you have any 35MHz radio system, you MUST always ensure thatyou EXTEND THE TXs AERIAL AS FAR OUT AS YOU CAN. You should never, ever,switch any (35MHZ) TX on without doing this first. If you have a 2.4 GHz system youdont have to worry as you cannot extend the aerials anyway.

There are also a couple of actual switches on top of the TX. The right hand switch is apull and hold for linking to a trainer TX, which you will not be wanting.

The FAR MORE IMPORTANT switch is the IDLE UP SWITCH which is located at theback left of the top of the standard 0406 ESKY TX. The two settings for this switch are

ON or OFF. If it is backwards, it is OFF, which is the position it should almost always bein unless you fully understand what it is and how to use it. -

UNLESS YOU KNOW WHAT YOU ARE DOING, OR UNLESSI TELL YOU IN HERETO TURN IT ON TO PERFORM THE SERVO POSITIONING, PLEASE DONT TRY TOEXPERIMENT WITH THE DEVILS SWITCH TO FIND OUT WHAT WILL HAPPEN PLEASE TRUST ME OR YOU WILL ALMOST CERTAINLY REGRET IT.

So, basically, at this stage of your helicopter flying career you should NEVER EVERHAVE THE IDLE UP SWITCH FORWARD unless you really mean it to be set to ON fora very good reason.

If this switch is NOT backwards right now, push it backwards and make sure it is thereproperly. Even put a rubber band on it somehow to ensure it cannot be flickedaccidently. If you do somehow enable this switch (most of us call it the EVIL or DEVILSswitch), your main rotor blades will instantly go to almost full throttle, you will almostcertainly tear all the teeth of the main gear, and as you can imagine, many other nastythings can happen.

OK, now switch the TX on and check that you have at least all but the last green LED onthe right lit. If the last one is not lit its still fine to use, but any lower and you really doneed to charge the batteries for the TX.


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OK, recheck to make sure the throttle stick is RIGHT AT THE TOP, and now connect theDEANS connectors on the aircraft so that the LIPO is at last connected and yourhelicopter is alive

There is a safety system built in to most radio systems that if an initial connection ismade with the throttle anywhere but fully down, it assumes a problem, and the motorSHOULD NOT ENGAGE. For absolute safety, you can release the mounting screws alittle and move the motor back so that the pinion will not engage with the main gear, oryou can remove the main rotors so that only the flybar and paddles is left to turn if itdoes still happen to try to spool up. If you leave the paddles on, SAFETY - HOLD THEAIRCRAFT FIRMLY until you KNOW IT AINT GOING TO SPOOL UP ON YOU.

The ESC on the aircraft should beep, and then a couple of seconds, beep again. On thesecond beep, pull the throttle all the way down, and then TURN OFF the TX. TheRX/ESC will now have remembered those positions for you. Please note that each

manufacturer uses different beeps, but basically you will get one, two or three beeps insuccession at each end of the throttle movement.

If you ever change to another TX (or a different ESC) you will need to repeat thisprocess.

FINALLY - DISCONNECT the LIPO for safety.

6.4 - Setting up the initial position of the servo horns

Now we come to the real meat and potatoes of the setup process. We call it themechanical setup because we will be working on the connecting rods and servo hornspositions to get the swash plate as near totally horizontal in all directions as we possiblycan.

So to achieve this, we first of all need to set our TX up to the correct settings at midthrottle, which is the point that the pitch of the rotor blades should be ZERO DEGREES.As always when you are going to switch the TX on, check that

SAFETY - All trim levers are centered, EXCEPT the throttle trimmer, whichSHOULDALWAYS BE FULLY DOWN.

The left stick will be at the bottom and centered, whereas the right stick will be centeredin both planes.

Are you sure you have that right ? - THINK SAFETY

OK, ONLY NOW CAN YOU TURN THE TX ON AGAIN..

Got enough of the power LEDS alight ? (all but maybe the rightmost LED)

OK, SAFETY - the MOTOR IS DISCONNECTED ISNT IT ?

Connect the LIPO in the aircraft.


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If so, and everything is switched on, you can **slowly** move the throttle lever up until itis exactly mid way thru its travel. If the motor buzzes or there is any movement in it at

all, disconnect the LIPO immediately and find out why it still has any power at all.

With the stock ESKY 0406 TX there are no alignment marks for the throttle position, soyou just have to try to guess this as best you can. This is the throttle position we alwaysuse when setting up the aircraft mechanically, but at all other times, we ensure that theThrottle lever is FULLY DOWN BEFORE the TX is turned ON.

IF YOU ARE USING THE STANDARD ESKY TRANSMITTER (MARKED AS 0406USUALLY) THAT COMES WITH THE Belt-CP, THEN THIS PARTICULAR TASK DOESREQUIRE THAT YOU HAVE THE IDLE UP SWITCH PULLED FORWARD TO THE ONPOSITION.

So do it now if you have done all the above safety checks.

If you are using a programmable TX such as the DX6i or Futaba etc, you should notneed to do so as both curves for throttle and pitch should be the same in the TX for thisoperation. Again, if your curves are not both linear, change them to be so for thisoperation.

So far, so good, here we go Stage 1 of the mechanical setup an adventure in itself !

Lay the TX to one side DO IT CAREFULLY you do not want to accidently change thethrottle position, and you are not going to be touching it again for a little while, but itMUST BE LEFT SWITCHED ON.

As you gently moved the throttle to the centre position, you may well have noticed thatall three of the swash plate servos moved as well. That is a VERY GOOD THING. Try itagain to make sure all three do move. If any one of the servos does not move, then asthey famously said from space Houston - we have a problem and you shoulddisconnect the LIPO in the aircraft and then turn off the TX immediately.

Here it is with the servo horn very close to being perpendicular


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So lets start our task with the Elevator servo, which if you remember from above is theone at the front on the right of the aircraft, and it has two rods connecting it to similar

swinging arm lever by the mainshaft.

What we want to achieve while the throttle setting is exactly central is for ALL of theservo horns to be as close to right angles to the body of the servo itself as possible. If itis not, which is quite likely, carefully undo the small Phillips headed screw that holds theservo horn on to the servo shaft and put it somewhere very safe. Now gently pull thehorn off the servos splined shaft, and then rotate it whichever way it needs to get it asclose to perpendicular to the body of the servo (NB - not the bottom of the aircraft, whichis probably horizontal).When you refit the horn to the splined shaft you still may not be able to get it to beperfectly perpendicular. If that is the case, try disconnecting the two connecting rodsfrom the balls on the servo horn, and then rotate the horn 180 degrees. Why, because

the splines in the servo horn are slightly offset by design, which means you may (or maynot) get a better result when it is fitted the other way around.

There is one more check that you need to do for the elevator positioning, and that is tocheck the little arm that sits inside the frame, and which is moved by this servo, andmake sure that it is pointing forward at 90 degrees to the main shaft. It usually will be,but if not, you may need to adjust the length of the two rods to get it to be in the rightposition. If you have to do this, do MAKE SURE that when you reconnect the secondrod, it is exactly the right length so that is aligned with the ball before you connect it. If itisnt, you will create a bad case of binding as each connecting rod will be fighting theother one. Think about it and I am sure you will understand what I am saying

Select the horn direction that gives the best position, and then reattach the connectionrods. Finally, find that little fixing screw I told you to put away safely and attach the servoarm to the shaft. Tighten it firmly, but do not over tighten it.

Great stuff, you are now one third of the way through this process, and I would bet youwill agree that it wasnt really too difficult, was it ?

So, now lets do the right aileron servo, as we have the aircraft lying on its left sidealready. You follow EXACTLY the same process as we have just described, apart fromthe fact there is only one connecting rod on this servo horn, going up to the side of theswash plate. If the horn on your servo only has a single arm, and you still cannot get agood perpendicular position, you might want to try one of the spare double ended servo

horns that you should find in your kit box somewhere. As previously, try them each wayaround until you get the best fit so that the servo arm is perpendicular to that servosbody. Once you have it as good as possible, carefully cut off the unused arm to stop ithitting anything else accidently.

Even better, you are now two third of the way through this process, and it is probablynow getting even easier ?

So, turn the aircraft over, and repeat the process on the left side aileron servo, exactlyas we have done previously.


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PICTURE Left Aileron servo with hornperpendicular

Right then, we have now reached that magic point where we can actually try to get theswash plate exactly where we want it, which relies totally on the fact that the threeswash plate servos have been set up correctly before we do so.

6.5 - Setting up the position of the swash plate

This is another critical step towards having a well balanced, smooth flying helicopter, soif you are getting a bit weary, TAKE A BREAK and come back to this later on after a stiffdrink or whatever you like to use to relax.

Had a break - Are you feeling better now ?

Great, lets proceed with stage 2 of the mechanical setup

By now I hope you are realizing that none of this is particularly difficult, its just aquestion of proceeding carefully and double checking every thing you do, and mostpeople can do it very successfully.

But as always please do Remember, Remember, Remember SAFETY FIRST !

So, if you took a break, have you remembered to check control levers and trims on theTX, and is the antennae fully extended WHAT A GOOD LITTLE FUTURE PILOT YOUARE..

Ok, stand the aircraft up again, ensure the LIPO is connected and the MOTOR IS NOTCONNECTED, and have a very careful look at the swash plate. It has probably movedto a different position if you moved the servo horns in the previous step, but dont worryabout it, as we are going to set it up now using those connecting rods that connect theswash plate to the servos you have just setup correctly.


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A CNC upgrade (thats why its purple) for the swash plate yours will probably be blackplastic

It doesnt really matter which one we start with, so I suggest that for the time being, wewill use the elevator position as our starting point by assuming it is in the correct positionalready. So you are probably asking, how are we going to make the rest of the swashplate exactly level with the front of the swash plate.

Here is the swash plate with positive pitch, as the front of the swash plate is very clearlyhigher than the rear. This position will cause the nose of the helicopter to rise.

Well, remember that we have three servos that control the swash plate, and we haveaccepted the elevator servo as being in the right position already, so it makes sense thatwe must need to change the connecting rods going from the left and right aileron servosto the swash plate. With me so far ?


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Ok then lets start with the left aileron servo. Is the left of the swash plate (when lookingfrom the tail of the aircraft) higher or lower than the front of the swash plate. Letsassume it is higher for now, so what we need to do is to SHORTEN the connecting rod

from the left aileron servo to make the swash plate move DOWN on that side. Carefullytake the rods off the balls on the servo horn and the swash plate. If you have ball jointpliers this is much easier.

Now to shorten a connecting rod, we need to turn one or both of the plastic ball jointconnectors clockwise. To lengthen them, you turn them anti clockwise. The minimumadjustment you can achieve here is one half a turn. When doing this it is always a goodidea to adjust both plastic ends nice and evenly so that the same amount of thread onthe connecting rod is visible. This will avoid having one plastic end almost falling of itsthread while the other is almost fully screwed in.

So go ahead and adjust your rod the number of turns clockwise (or anti clockwise) that

you think it will need to bring the left hand side of the swash plate to the same height asthe front of the swash plate. Rather than pushing the ball joint on and off endlesslywhich can easily weaken or even break them, just try to hold the rod in position on theoutside of the connector balls without pushing them on completely and hold them therewhile you recheck the level of the swash plate.

Repeat this process until you have achieved the aim we started out with, which was tomake the left side of the swash plate sit at exactly the same height as the front of theswash plate.

Got it right GREAT STUFF !!

If not, repeat the process again until you do reach the magic setting.

So now we have a swash plate that has the left hand side and the front at exactly thesame height are you sure ?

Just have another quick look from all angles to be sure.

If you are still sure, fit the connecting rod properly so that the plastic loop is firmly overthe connecting balls at each end, and then turn the aircraft around and repeat thisidentical process with the right side aileron connecting rod.

Is the entire swash plate totally level now ?

Wow that makes you a semi qualifiedhelicopter engineer stage 2, very well done.


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PICTURE Here is what a swash plate that is setup totally horizontal looks like from theright side of the aircraft

What we have just done is the basic work required to be able to set any collective pitchhelicopter up, as they all use the same basic processes.

There is however one more thing that needs to be checked now we have our swashplate level. Just above the swash plate you will see the mixer/washout levers wementioned before. Well, at 50% throttle, with the swash exactly level, these shouldALSO be exactly level. TO see what I mean, try increasing the throttle and thendecreasing it again and watch the washout levers move. See what I mean, they movequite a bit in opposite directions, but at one point, which is the 50% throttle position, theyshould also be exactly level with each other. If yours are not, work out which way theswash needs to move to get them level by moving the throttle and noting which way theswash has to move to get them level, then return the throttle to 50% setting and adjustALL THREE OF THE CONNECTING RODS TO THE SERVOS the correct (and same)way until the mixers are also level.

OK, VERY WELL DONE, thats probably the most technical thing you will have to do.


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PICTURE And here is what it looks like from the front of the aircraft. You can just seemy washout arms are also dead level above the swash plate.

Please excuse my golf clubs in the background, I forgot to move them before filming this


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6.6 - Set the Rudder Servo up

Before we move on to the final things we need to do to the rotor blades, lets just set up

the rudder servo horn as well, as this still has to be set up to be perpendicular to theservo body.

The Rudder servo with servo horn perpendicular to the servo

It is usually a good idea to remove the connecting rod from the ball on the servo before

starting this. You will need to lie the aircraft on its left side to be able to see the angle ofthe rudder servo horn as the servo is actually mounted directly onto the boom in whichthe rudder drive belt goes to the tail.

OK, this is exactly the same process as we have been doing with the other servos, soyou dont need me to tell you how to do it do you ?

Once the servo horn is perpendicular, refit the connecting rod firmly to the servo horn.

6.7 Fitting the rotor blades to the aircraft

OK, One other point you need to check if you have been following along with me so far.You need to check to ensure that those very carefully balanced rotor blades are actuallyfitted to the helicopter before we commence the next setup operation.

Optional check

Before doing so however, you might want to check the tightness of the rotor bladeholders that sit in what is called the feathering shaft. These should be nipped up so thatboth the blade holders can rotate freely, but there should also be just a slight amount ofresistance as well. This is because inside the rotor blade holders there are variouswashers and other stuff, but most importantly each blade presses inwards against itsown rubber ring that is there to provide a small amount of flex in the movement of the


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rotors up and downwards. Due to the very important job they do, they are unsurprisinglycalled rubber dampeners

To adjust this tension you will needa pair of box spanners that will fit the two Nylocknuts you can see inside the rotor blade grips, and that are not too large as to be able toslip into the blade holder.

If you need to tighten them, slide a box spanner over each nut, and gently tighten it alittle bit, then recheck the tension. It is usually best to go a tiny bit too far, and then backit off very slightly.

Getting this feathering shaft nut tension right usually results in a far more stable aircraftand will certainly make tracking the rotors far easier.

OK, Now lets get on with it and fit our rotor blades shall we.?

To do so is very simple, but lets just cover the main points here for completeness.When you put them away safely, you also put away the fitting bolt and Nylock nut asinstructed DIDNT YOU ? Now get them

Right place the aircraft with the nose pointing to the RIGHT

Next place the rotors in front of the aircraft, and lets ensure that we have them pointingthe correct way. The main rotors on a Belt-CP, and many other R/C helicopters rotateclockwise, so you need to have each blade oriented so that the leading edge is at thefront when the blade is moving forward (clockwise). Turn the rotor head so that the

flybar is pointing across the aircraft. Now take one of the blades and lie it to the left ofthe mainshaft, with the mounting hole at the right, and the sharper edge of the rotortoward you (this is the TRAILING edge) which means the leading edge is correctlyoriented to go clockwise leading edge first.

Now put the other blade to the right of the first one, with the TRAILING edge of the bladeaway from you, so that this is also correctly oriented with the leading edge coming firstwhen the head rotates clockwise.

Now I normally suggest that you push the Nylock nut carefully into its recess under therotor blade holder on the aircraft, ensuring that it is pushed in as far as it will go. Do thisin both rotor blade holders now. SAFETY - Dont forget to put a small drop of thread

lock on the face of the nut first so that it will lock it nicely when the bolt is fitted., as weDO NOT WANT rotor blades flying off everywhere, do we ?

Finally, pick up the left hand rotor blade, slide it into the rotor blade holder carefully,making sure you dont turn it around the wrong way as you do so, and use a smallscrewdriver or similar to push through the hole in the blade holder and down through therotor blade and through the bottom hold of the rotor blade holder and then wriggle itabout gently to make sure the blade mounting hole is pretty well central to that of theblade holder.

The blade should stay there, so get your bolt and gently remove the screwdriver andstart to wind the mounting bolt downwards from the top. You will find that it needs to be


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screwed all the way through the top of the blade holder, the blade itself (lightly anyway)and the bottom of the blade holder, and finally down through the Nylock nut.

Pinch it up so that the blade doesnt swing pivot in the blade holder by itself, and thenrepeat EXACTLY the same process with the other rotor blade. Dont forget to check theorientation of the second blade so that it is leading edge at the front will you ?

The final thing to be done is to set the amount of pinch required for the rotor blades.Basically all you are trying to achieve is to have the blades only start to slip down slowlyif you hold the helicopter on its side and give it a gentle shake. So slowly loosen eachbolt until you achieve that amount of resistance.

Right, now your rotor blades are fitted correctly, you can recheck the tightness of thefeathering shaft nuts more easily by rocking the fly bar up and down from one side to theother. If it moves totally freely, your feathering shaft nuts are NOT TIGHT ENOUGH.

Equally, if it is hard to move, the feathering shaft nuts are TOO TIGHT.

If either case happens to you, you just have to remove the rotor blades again and repeatthe tightening process described above.

6.8 Setting the rotor blade pitch range correctly

BUT, and there is always a BUT isnt there, we have no idea what actual pitch setting wehave a central throttle, as we simply assumed the elevator setting was right for the timebeing while we set up the swash plate, so now we need to check it to find out if we wereright.

Hopefully you purchased a pitch gauge with your Belt-CP, as if not, this next process is alot harder, if not really impossible to do successfully, as we are going to be trying tomeasure the exact angle of attack (pitch) of both rotor blades.

Before we go into how to set the pitch up, lets talk briefly abut what PITCH is in terms ofCollective pitch helicopters, and see what it does.


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A typical pitch gauge

As you already know, assuming you have read this through so far, (You have been

following along havent you ?) whenever you increase or decrease the throttle on yourTX, the CCPM mixing built into it also increases or decreases the amount of pitch thatthe rotor blades are set to, and this in turn governs the total amount of lift we have. Youmay also be a little surprised to learn that most helicopters do not simply have pitchangles that go from zero degrees at low throttle to xx degrees at full throttle.

In fact, at low throttle they are set to provide a negative pitch (angle of attack) whichmeans that if you pull the throttle right back to the bottom, the aircraft will not simplySINK to the ground gently, as if it were a fixed wing aircraft gliding, it will actually pullitself down out of the air as the rotor blades are now providing negative lift, so that arepulling downwards out of the air. It is very important to always remember this if you wantto avoid a heavy landing or much worse.

Ok, having explained briefly what pitch is, we need to decide what pitch range we want.

In the case of the standard ESKY 0406b TX you cannot choose this, as it is pre-configured in the TX. However, the range you can expect to find available is from -9degrees to +9 degrees approximately. As we cannot change this range, you may beasking how or even why we have to set it up anyway ?

The reason is, as always, very simple. The one setting that is almost always cast instone is that the pitch setting that you should see when you have the throttle at exactlythe centre point of its travel will always be ZERO DEGREES.

You may be wondering why this is ?

Well, because our pitch range is likely to be from -10 degrees to + 10 degrees, at somepoint, we need to decide exactly where the central, zero degrees will be on our throttlecurve. It has been learned by long and hard experience that for the basic setup of anyCollective Pitch helicopter, this magic point should be at exactly 50% throttle setting.

So, we can see that yet again, we need to set up our TX with all the trims in the correctpositions, and the throttle lever at the exact mid point of its travel.

SAFETY You have got the antennae of the TX FULLY EXTENDED and the motorDISCONNECTED havent you.


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Good, turn on the TX, and then connect the LIPO in the aircraft.

Check that you have the throttle at exactly half way and move the TX away from you soyou do not knock it over.

Take your pitch gauge and slide it over one of the rotor blades, sliding it all the waydown until it is about 4 inches from the blade grip. Remember, have a little play withyour pitch gauge first You will find that it has a spring that lets you open up the slot forthe blade to slide into to save you damaging the edges of the rotor blades.

Ok, now we should again find our swash plate is nice and level all the way around, sowe now need to read off the pitch setting on each blade separately. They shouldhopefully be somewhere around zero degrees, but please dont panic if they are not.

If you are getting a different reading for each rotor blade, as is very likely, we need tocorrect that first. The topmost adjustable connecting rods between the rotor blades andthe swash plate are where we do that. Follow the rotor arm grip carefully, and identifythe two adjustable rods that connect to the balls on the rotor blade grip. These are whatwe are going to adjust our pitch level with. Now, If we have both blades higher than therequired zero degrees, it makes sense to adjust the blade that has the highest pitchdownwards to match the other. If the reverse is true, then lets raise the pitch on thelower blade to match the other blade. Dont worry if you cannot get these absolutelycorrect, just get them as close as possible. We can handle the discrepancy later on.

Right, so now we have both blades giving us the same, but wrong pitch ?

Fine, lets assume for this discussion that they are now both showing +5 degrees. Thatsno problem.

Can you guess what we are going to adjust to bring the pitch on both rotor blades downto zero ? HINT - Think about what we did when we setup the swash plate to be totallylevel.

CORRECT, did you get it right - we are again going to adjust the lengths of theconnecting rods that go from the servo horns to the swash plate outer ball connectors,which will raise or lower the entire swash plate, while keeping it level, until the pitch iszero degrees.

Easy really isnt it, all you got to do really is ensure that you adjust each of the rods byEXACTLY the same number of turns to ensure the swash plate remains level as wechange the pitch.

So, we know (or rather you know - dont you ?) that we want to bring the swash plateDOWN to decrease the pitch on both of the rotors until they are set to zero degrees.

Fine OFF YOU GO. I am sure you dont need me to tell you howto do that simple little job now, as you have done it before and are becoming an expert.


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I will now take the opportunity to wander off and have a small drink myself to settle mynerves, while YOU get on with this important task, as I know you can handle it withouthaving to ask me any silly questions now.

ALL DONE ?. Are they both set to be exactly zero degrees ? Is the throttle on the TXstill set to exact central throttle Remember check and check again to be sure you haveit right.

Are all of the connecting rods securely fitted to the balls at both ends ?

OK then, we can (ONLY) now find out for the very first time what pitch range YOURHELICOPTER can provide. Move the throttle stick on your TX down to the very bottomand check the pitch again. It should be around -8 to -10, but dont worry if its one or twodegrees different to that.

Now push the throttle stick all the way up to full throttle and measure the pitch again. Itshould be around +8 to +10, but dont worry if its a few degrees different to that.

Because I just know that by now you have learned to be really careful when working onhelicopters, you might as well check the central throttle pitch again as well forcompleteness.

SAFETY What do we normally do when we have finished working on the aircraft Correct WE TURN OFF THE AIRCRAFT **FIRST** by disconnecting the LIPO ANDthen we turn off the TX.

So now, lets review what we have achieved shall we ?

Your last check has shown you that you have pitch range of around -10 to +10 degreeswhich is quite sufficient if you are still learning to hover. We also know that at centrethrottle, the pitch is set to zero degrees.

Surely that must be all we could possibly ask you to do before you can go and try to flyyour new Belt-CP. Sorry, but the answer is still a resounding NO.We have not touched the question of rotor blade tracking as yet, neither have we lookedat the tail rotor gyro, so bear with me a little longer YOU REALLY ARE NEARLYTHERE.

But before we do that, lets just set the central pitch point for our rudder, as this is a nice

quick and easy job to do.

As always, throttle at centre, all trims at the usual setting, and look at the slider thatmoves in and out on the tail rotor shaft. It should NOT be totally central as helicoptersrequire a bit of rudder immediately to counter the rotating forces of the main rotors. Youneed to adjust its position so that it is about 1/3rd away form the boom and 2/3rd awayfrom the tail rotor blades.


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PICTURE - Rudder correctly centered, note it is closer to the boom than the tail blades

How do you set this very simple. Look at the servo from above and you will see twosmall phillips headed screws holding the servo mounting to the boom. Just loosen theseabout one turn, and you will find that you can slide the entire servo and mountingforward and backward along the boom. Move it forward or backward as necessary sothat you have the slider in the position discussed above, and then RELOCK the screwsfirmly, but not too tightly.

One thing that is worth noting is the way the tail rotors are fitted, and which way aroundthey should spin. In common with many real helicopters, the tail rotors are usually found

to spin upwards into the downwash of the main rotors, which gives them a bit morepower. This is true in the case of the Belt-CP, so the tail rotors rotate ANTI-CLOCKWISE when viewed from the right side of the aircraft. It is also worth checkingthat the connecting balls for the control rods that attach to the tail rotor blade grips isalso AT THE LEADING EDGE of the tail rotor blades. You can see this quite clearly inthe next illustration.


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PICTURE The tail rotors fitted the CORRECT way around. The leading edges are onthe left of the top blade and right of the bottom blade. The connecting balls are on thesame side as the leading edge of the tail rotor blades.

PICTURE - Here is my Rudder servo immediately behind my stock ESKY gyro, seenfrom the top and looking from the left side of the aircraft. You can see in the left picturethe two philips screws on the mounting that are used to allow the servo to be movedalong the boom.

Another point worth noting is that if you have the stock ESKY gyro, which is only a RATEgyro, not a Heading hold gyro, you should check to ensure that the small switch you willsee marked NOR/REV is set to REV (for reverse) This is the correct setting for thisgyro. If you leave it set to NOR then the gyro will actually help the tail to turn even

faster, which is something you really do not want for your first flight.

What I hear you asking, is the difference between a RATE gyro and a HEADING HOLDgyro ?

Well, a RATE gyro simply tries to stop the tail moving around and changing position toomuch due to the effects of the wind etc, but it has no concept of what direction it may bepointing in.

The HEADING HOLD gyro on the other hand does not worry about effects of wind onthe aircraft, it always tries to maintain the same heading, so as you turn the tail, it isactually fighting you a bit.

For learning to hover, it is strongly recommended that you use a RATE gyro, foralthough a HEADING HOLD gyro makes the tail stay nice and still when hovering, youwill not learn to control the tail, and you really do need to do so.

The HEADING HOLD gyro is used much more when flying forward (called FFF) as thenit tries to keep the aircraft heading solid, and as you make a turn, you bank the aircraftAND you have to also ensure you handle the tail to follow the nose, or the aircraft willsimply go around the turn more and more sideways until you have a nasty moment.


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PICTURE - How to adjust the tail rotor belt tension

6.9 - Setting up the tail drive belt tension

If once you have set the tail servo up, the tail rotor control has been positioned 1/3 rd ofthe way along the shaft from the tail rotor gearbox. You should also check the tail rotorbelt tension. You do this by looking down from the top of the aircraft just inside the leftaileron servo, and you will see the drive gear and the belt. Slip a screwdriver down tothe outside of the side of the belt and gently push it inwards toward the other side of thebelt. It should be set so that it can be pushed to around the middle only, it should not betoo tight, but should not be able to be made to touch the other side of the belt.

If you need to adjust this, you need to loosen the four Philips headed screws that you willfind in the four holes you can see in the picture above and below the boom tube. Undothese so that you can JUST move the boom in and out. NB the boom WILL NOT TURN,it only moves directly inwards and outwards. Now slide the boom so that the beltreaches the correct tension, and then make very sure that you retighten these screwsfirmly as you certainly do not want the boom to start moving when the helicopter is inflight.

The very last thing we must do as far as the rotor blades are concerned is to make surethat when they are spooled up to speed, the tips track (run) in the same plane. This isanother reason that we have the red and blue strips on the tips of the rotor blades.


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6.10 Balancing the fly bar and paddles

Before we start to track the main rotor blades, we need to make sure that the fly bar and

paddles is also balanced, as these are also a part of the mass of stuff rotating at thetop of your mainshaft.

The first and obvious check is to ensure that there is no end to end movement if you pulleach paddle outward along the flybar. If there is you need to slight release the collarsthat are immediately to the outside of the fly bar control arms and then push them upsnugly against the control arms so there is no slop. Then retighten these.

Next, check to ensure that both of the paddles are the correct way around, which is thatthe leading edge of each blade faces forward, which means they will be at the front asthe rotor head rotates CLOCKWISE.

A final check of the paddles is to check that are both exactly level with each other whenviewed along the flybar. In other words they both have the same pitch, which at midthrottle should then be zero degrees of pitch. Also check to see if the two control armsthat connect to the head are also horizontal.

Now, if you looked at the Belt CP manual, you will see that an approximate distance isspecified for the gap between that locking collar we have just looked at and theequivalent one that is immediately on the inside of each of the paddles themselves. Infact the actual distance is not critical, but the paddles should be screwed on a sufficientdistance onto the flybar as to ensure they cannot fly off. It is a good idea to take themoff and then count the number of turns you use to replace one paddle securely, and thenscrew the other one back on the same number of turns.

Finally you can use a normal ruler, or better yet a vernier calliper if you have access toone, and carefully measure the distance between the two locking collars. Naturally,these should be EXACTLY the same on both sides. Now retighten all grub screwsfirmly.

ADVANCED INFORMATION

If you want be really professional about the fly bar and head assembly, you candisconnect the motor pinion so that it no longer meshes with the main gear, remove thetail drive belt, and then after checking that the head spins freely, hold the aircraft on itsside with the fly bar paddles horizontal and see if one drops down more than the other.

If so weight is required on the lighter paddle blade. To make sure the entire headbalances level.

THIS ADVANCED BALANCING IS NOT NECESSARY IF YOU ARE PERFORMING AFIRST SETUP AS A NEW PILOT/BUILDER, BUT THE INFORMATION IS PROVIDEDHERE AS YOU MAY WANT TO DO IT AT A LATER DATE.

6.11 Setting the rotor blade tracking

CAUTION WARNING THE NEXT OPERATION INVOLVES THE HELICOPTERHAVING ITS ROTOR BLADES FITTED, AND THEN SPINNING THESE UP TO


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AROUND 1000+ RPM with the throttle. This means those rotor blade tips aremoving VERY FAST, so PLEASE do this VERY CAREFULLY

Most of us put together what is called a Lazy Susan to let us run the aircraft up with itsrotors fitted and spinning. This is just some form of turntable that you can firmly attachthe helicopter to so that it is allowed to rotate, but of course, so that it cannot rise up ordown at all.

If you do not have such a thing, you can do it by strapping the aircraft down very firmlyso that it cannot even rotate, but in this case, you will need to be very careful how manyrotor rpm you let it go to. Use the skids to secure it to something level and veryimmovable.

Whichever method you use, it is a very good idea to put some dense foam or a similarmaterial under and on top of the skids, and then fix the helicopter down just tightly

enough so that it can still move up and down a bit by compressing the foam. This willhelp to stop unwanted harmonics causing vibrations throughout the aircraft. Even somethickish polystyrene sheet will do the job quite well.

By now, you should have the rotor blades fitted to the aircraft if you have been followingalong, and now it is SECURELY ATTACHED TO A LAZY SUSAN OR OTHERIMMOVABLE OBJECT BY ITS SKIDS ?

Please do NOT consider for even a second that maybe you can just put a book orsomething over the skids and try to do this operation You may well injure or killyourself or someone else, and damage the aircraft severely.

OK, enough warnings and caveats, you are now ready and comfortable to check thetracking are you ?

As usual, check the TX trims and stick settings, ensure that all connecting rods aresecurely fitted over the various ball joints, extend the TX aerial, turn on the TX, andfinally, connect the LIPO in the aircraft.


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THE MOST IMPORTANT WARNING IN T

3_Puesta a punto del Belt CP en Inglés

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