in detiail making of rc helicopter

8/3/2019 In Detiail Making of Rc Helicopter

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MAIN BODY:

The material that I uThe material that I use to make the main body of the helicopter

would make you feel surprise. It is the circuit board ( after removing the copper layer

) that purchased from electronic shops. It is made of a kind of fiber which gives

abnormal strength to it

The circuit board is cut to the rectangular shape as above( 98mm*12mm). As you can

see, there is a hole on it which is used to house the main shaft holding tube as below:

The main shaft holding tube is made from a white plastic tube (5.4mm*6.8mm) and

two bearing (3*6) are installed at both ends of the tube. Of course, the ending of the

tube are first enlarged in order to house the bearing firmly.

Up to now, the basic structure of the helicopter is completed. The next step is to install

the gear as well as the motor. You can take a look at thespecificationfirst. The gear I

used is from Tamiya gear set that I bought long long time ago. I drill some hole on the

gear in order to make it lighter and have a better look..
http://www.angelfire.com/blues/heli_project/spec.htmhttp://www.angelfire.com/blues/heli_project/spec.htmhttp://www.angelfire.com/blues/heli_project/spec.htmhttp://www.angelfire.com/blues/heli_project/spec.htm


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Would you think it is just too simple? Well, it is really a very simple design as the tail

rotor is powered by a separate motor. This eliminates the needs not to construct a

complicated power transfer unit from the main motor to the tail. The tail boom is

simply fixed on the main body by 2 screws together with some epoxy adhesive:

For the landing gear, 2mm carbon robs are used. Totally 4 holes are drilled on the

main body ( each end 2 holes ).

All the robs are glued together by instant glue first and then by

epoxy adhesive.

The skid set is made from balsa. They are very light and can be

shaped easily.

Swashplate is the most sophisticated part of a RC helicopter. It seems to be a simple unit of a factory on

However, it is a whole new thing of making one by yourself. Here is my design based on my own little

knowledge about the swashplate. What you need includes:


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1 ball bearing ( 8*12) 1 plastic spacer (8*12) rod end set ( for holding of the aluminum ball in the swashplate ) aluminum ball ( from ball linkage set 3*5.8 ) aluminum ring

epoxy adhesive

The rod end set has first been cut into a round shape. It is then inserted into the plastic spacer as shown

below:

Make sure that the aluminum ball placed in the rod end can be

moved freely. 2 holes were drilled on the plastic spacer in order to

house two screws that used to hold the ball linkage.

The back of the swashplate In my design, the swashplate is fixed on the main shaft. Thiis simply done by applying some glue between the aluminu

ball and the shaft

# be careful when applying epoxy to this tiny unit or you would get every part being


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glued together.

My instructions are too confusing? Here ismy draftof the swashplate which might help you. I still find

that my design is a little bit too complex. If you have a better design, please let me know!

For the rotor head, I choose the same material as the main body - the circuit board.

First of all, I have to claim that the rotor head must be sturdy enough to withstand any

vibration or it could be very dangerous.

The control system I used here is the Hiller system. In this simple control system, the

cyclic controls are transmitted from the servos to the flybar only and the main blade

cyclic pitch is controlled by the flybar tilt only.

The first step is to make the middle part:

It is actually a 3mm collar which can be fit into the main shaft. A 1.6mm bar is

inserted horizontally into the collar. The above unit makes the rotor head movable in

one direction.
http://www.angelfire.com/blues/heli_project/swashplate_hand.jpghttp://www.angelfire.com/blues/heli_project/swashplate_hand.jpghttp://www.angelfire.com/blues/heli_project/swashplate_hand.jpghttp://www.angelfire.com/blues/heli_project/main_body.htmhttp://www.angelfire.com/blues/heli_project/main_body.htmhttp://www.angelfire.com/blues/heli_project/swashplate_hand.jpg


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There are two holes just above the collar which is used to, as you can see, house the

flybar. All the parts that I used was first fixed together by instant glue. They are then

fixed firmly by tiny screws (1mm*4mm) as shown below. In addition, I add epoxy

adhesive. The rotor head will spinning at very high speed. Never overlook the

potential for causing injury this little machine has if anything got loose. Safety is

paramount!

As I mentioned before, the Hiller control system is used in my design. All the cyclic

controls are transmitted to the flybar directly.


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There is a metal bar ironed perpendicularly to the flybar. It holds the metal ball of the

ball link in position. Here is how the ball link is made:

The rob ends are shortened and a metal bar is used to connected them together. the

metal bar should be inserted deep into the rob ends and fixed with epoxy adhesive.

In addition to the ball link, an "H" shaped anti-rotating unit is a must for the control

system. It helps to keep the ball link in position. The materials needed are showed inthe above photo.


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In order to stop the lower part of the

swashplate from moving, an anti-rotation

unit is also needed here. It is simple asmall board with two pins inserted on it.

The tail rotor consists of a motor, tail blades, tail shaft holding tube and a blade

holder. The tail control is managed by changing the RPM of the tail motor. The

drawback of this kind of control system is its sluggish response as the rotor pitch is

fixed. However, it makes the whole design much more simpler and reduces a lot of

weight.


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In an ordinary R/C helicopter, the gyro work together with the tail servo. However, in

this design, the gyro has to work together with the ESC (electronic speed controller).

Will this work??? At the beginning, I try this with an ordinary gyro ( the large one for

the gas helicopter). The result is really bad that the RPM of the tail rotor changes fromtime to time despite the helicopter is standing on the table. I buy a micro-gyro later

which is specially designed for small electric helicopters and to my surprise this

works great.

Here is the measurement of the tail blade. It can be shaped easily

from a 2mm thick balsa. the tail blades make an angle of ~9on the

blade holder

The photo shows all the things that the tail part consists. The two

balsa blades are hold by a hardwood holder which helps to give afixed tail pitch. It is then secured on the gearwheel by 2 screws.

The motor is simply glued on the tail boom by epoxy adhesive

and the tail shaft holding tube with the same way on the motor.

The tail blade is made of balsa. They are covered with heat

shrink tube in order to reduce the friction between the blade and

the air.

The pitch and the weight of the two blades must be exactly the

same. Tests must be performed to ensure that no vibration occur.


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Only two servos are used in my design. One is for the elevator and the other one is for

aileron. In my design, the aileron servo is installed between the motor and the main

shift holding tube. In this way, the tube has made use of the sturdy plastic case of the

servo as one of its supporting medium.

This arrangement gives extra strength to the

main shift holding tube as one side of the

servo is glued to the motor while the other

side is glued to the tube. However, the

mobility of the servo as well as the motor is

lost.

In order to make the whole structure sturdier, an additional support is added to the

main shift holding tube. It is also made from circuit board with some holes drill on it.


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Receiver

The receiver I use is GWS R-4p 4 channel receiver. Originally, it is used with micro crystal.However, I can't find one which fit with my TX's band. So, I give my try to use the large one from

RX. It eventually works great and no problems have occurred up to now. As you can see in the abo

picture, it's really big when compared with the micro receiver. The receiver is only 3.8g ( extremelight weight ) which is very suitable for indoor helicopter.

#Although the receiver has only four channels, it can bemodifiedto a five channel RX.

The tail Esc

Here you can see the speed controller that is used in my helicopter. It is placed at the bottom of the

gyro (see the photo below). Woo!! Really small size with only 0.7g. It is a JMP-7 Esc that I bougfromeheli. I really can't buy one from local hobby shops here in Hong Kong. Also, this tiny Esc

works great with the gyro. I just simply connect the signal output of the gyro to the signal input of

Esc.

The micro-gyro
http://www.angelfire.com/blues/heli_project/collective.htmhttp://www.angelfire.com/blues/heli_project/collective.htmhttp://www.angelfire.com/blues/heli_project/collective.htmhttp://www.eheli.at/http://www.eheli.at/http://www.eheli.at/http://www.eheli.at/http://www.angelfire.com/blues/heli_project/collective.htm


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This perfect micro-gyro is made by GWS. It is temporarily the lightest gyro that I can find in the

world. Unlike the previous GWS gyro that I used in my gas helicopter, it is very stable and the cenpoint is very accurate. If you plan to buy a micro gyro, it would certainly be a good choice for you

The tail motor

The motors in the above photo are 5v DC motor,micro DC 4.5-0.6, andmicro DC 1.3-0.02 ( fromleft to right ) In my first attempt, the micro4.6-0.6 is used. The motor burns out quickly ( or I shousay that the plastic component in the motor melts) as the power demand of the tail rotor is much la

than that I expected. At the moment, the 5v motor is being used in my helicopter which is still in v

good condition.

The current tail motor is a 16g GWS motor which provide much more power. For more informatio
http://www.wes-technik.de/English/Motors3.htmhttp://www.wes-technik.de/English/Motors3.htmhttp://www.wes-technik.de/English/Motors3.htmhttp://www.wes-technik.de/English/Motors-submin.htmhttp://www.wes-technik.de/English/Motors-submin.htmhttp://www.wes-technik.de/English/Motors-submin.htmhttp://www.wes-technik.de/English/Motors-submin.htmhttp://www.wes-technik.de/English/Motors3.htm


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please go to the page "flybarless CP modification II"

The main ESC:

The first photo shown above is a Jeti 050 5A brushed electronic speed controller. It was used tocontrol the speed 300 motor in my helicopter before. As the speed 300 motor is now replaced byaCD-Rom brushless motor, the Jeti 050 had been replaced by a Castle Creation Phoenix 10 brushl

ESC.

The following diagram shows how the components are connected to each other. The connections at the

receiver is not in order. The GWS R-4p is originally a 4-channel Rx. It is modified in order to provide an

extra channel for the pitch servo.

In a fixed pitch design, only 2 servos are needed. A computerized Tx is needed as the the tail control must be mixed with the throttle control. For a
http://www.angelfire.com/blues/heli_project/collective_2.htmhttp://www.angelfire.com/blues/heli_project/collective_2.htmhttp://www.angelfire.com/blues/heli_project/collective_2.htmhttp://www.angelfire.com/blues/heli_project/brushless.htmhttp://www.angelfire.com/blues/heli_project/brushless.htmhttp://www.angelfire.com/blues/heli_project/brushless.htmhttp://www.angelfire.com/blues/heli_project/brushless.htmhttp://www.angelfire.com/blues/heli_project/collective_2.htm


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Piccolo micro helicopter, this task is performed by the Piccoboard. For my design, this is done by

function "Revo-Mixing" in the Tx.

in detiail making of rc helicopter

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