Amazing!...a Nigerian teenager from Abia, builds a flying helicopter from scratch. I like flying things very much that I decided to put up research about them, he says. How they can stay aloft, agaist gravity, move to their desired direction and land whenever they want. Flying machines now full the air flying many times faster than birds. Thank to the write brothers who persited in making something fly even though it may sound like illlusion in their own time. Flying rc helicopters has been very enjoyable but flying your made is more enjoyable. I have taken time to study the various tricks that rc helicopters can perform, thus building mine. Building rc helicopters has commonly been done with helicopter kits, but in the apsence of kits one can still make something fly. I believe I can use what I have to get what I need, besides, the helicopter parts sold out there are still products of processed materials. Yes I can build with things around me since I don't have money to import, besides, fabricating my own parts make me happier. One may ask how I made out such time for trials.......yes I continued in persistence because I have no alternative, I found out that I enjoy model making even though others may call it a boring activity. Here is how I built my rc helicopter at home.

POSTS FOLLOWING SHALL BE ON HOW I MADE IT.
My heli is a coaxial type.
It does not fly with gyros, servos, swashplate, transmitter, reciever, electronic speed controller simply because I do not have them.
But my heli can fly forward and leftwards and can still rotate about a fixed point on air.
There is no battery inside it, rather it uses wire conection, my battery will be on my hand.
HERE WE GO

MOTOR CHOICE,,,POWER Friends I tried over and over again before I could understand motor work. This I tried with DVD motors with other things fixed, but it would shake, vibrate and strike as if it wanted to fly. But in all efforts it never flew, I still continued because I had only one objective that is to make my heli fly, though it was not easy. I replaced motors continuosly, because I found out then that even DVD motors vary in speed and mass, but the speedy ones were hevier and could not produce enough lift to lift its weight. Fortunately, in my motor replacing process, I found a motor from camera machine, it looked very good, I first tested with battery and the speed was inpressing though it was not heavy. This made me start reseach on types of motors and how they work. My research proves that before a motor is chosen, the ratio of weight to power must be known. Here, motors with high weight to power ratio would never lift your helicopter, DVD motors are good examples, unless they are rewined which is more complicated. However some motors are designed to produce high trusth, thus, they have high power to weight ratio, and can perform the desirable task of lifting your helicopter. This specially designed motors are called brushless motors and can be found in computer central unit, hair driers, camera machines and some CDs. With these, I chose brushless motors for my rc heli.
Click here https://www.nairaland.com/5032212/how-built-rc-helicopter-home#75874422 to see photo gallary.
Feel free to call me 07088713141

GEAR WHEEL SELECTION;>;>
this factor I will say was the most critical...... Yes because you would not know what 1 teeth difference in geer wheel can cause to your heli. I tried, tried and tried in replacing geer wheels of different sizes and different teeth number but could not get the one just ok for my heli. This made me have my box full of gear wheels. I put up a research which proved to me that everything I was doing in selecting gear was a childish play, even though I used big motor gear to small shaft gear, I still used gear wheels with incompatibility in teeth. Though I did not know the reason why pinion gear(motor gear) was small and the main gear(shaft gear) was big, I used the system. But I knew this would definitely decrease my speed. Further reserches proves that, the ratio of the pinion to main gear should be determined which should always be around 6-9:1. This means that the main gear should be 6 to 9 times greater than the pinion gear in teeth number, 6 main gear teeth, one pinion gear tuth, 72 main gear teeth, 12 pinion gear teeth. This seems to be complicated in coaxial helis, because, they have the main gear, the pinion gear and what I call the intermidiate gear. It is simply calculated by adding the teeth numbers for main and intermidiate gear to be in ratio with pinion gear teeth. In my heli I used 6:1 and it is working pretty well.

Pls why must you use gears why can't you just use only the electric motor

WHY MUST I USE GEAR You don't use the motor alone because the possibility of any rc helicopter lifting into the air is a measure of the stability of the spining sector. When you just add the motor shaft lenght and fix your rotor head and blades, the motor tends to spine faster than your rotating sector still in same fit. This in turn causes great torque and less lift, because lift is always inversely proportional to torque. Remember your shaft, rotor head and blade are heavy rotating setup, what do you think happens when they are spined nearly in same speed as the motor, remember the motor is fixed. When big gear wheel is used on the shaft and the small on the motor, this make the whole set up stable. If 6:1 gear ratio is used, this means that when the pinion gear rotates 6 times the main gear rotates only once. This makes the shaft rotate on its own, even though the motor on a high speed, the shaft does not compete, it rotates with a different speed and this makes it stable. Higher stability is higher lift. Below is mine...
Click here https://www.nairaland.com/5032212/how-built-rc-helicopter-home#75874422 for photo gallary.
Feel free to call me 07088713141.

MY MOTOR MOUNTING SYSTEM Below is my motor fit

Following

We are all good buddy
here they are....

What you can see above is my motor fit. It is just a plastic tube open at both ends, very easy to mount the helicopter motor. Mounting of motor has been commonly done with screws, where you will have to make holes on the main body to match exertly the holes on the motor. This is then completed by fastening the screws through the main body and the motor. But making the holes match becaomes a problem, I tried, tried before I made it. But now with my system you will only need a plastic tube that is open at both ends and fit your motor very well. Your motor will have to be forced into the tube with a little effort. The motor is glued or epoxised to the main body and the motor is fit into the tube. You will get to understand it more in due cost. Feel free to ask me any question I will gladly answer them.

Making the two shaft and gear
during chosing of shaft I found out that the shaft should be strong and not too long. Just ok not too big not too lond. For my coaxial type I had to find two shafts one will be rotating inside the other. I built coaxial type because I have only one brushless motor....yes coaxial can fly even without tail motor, tail motor is there onl for direction. I got my inner shaft from a bycycle, it is just the spoke cut and shaped very well to a desirable size. My outer shaft should be hollow, this led me to find a radio pole, the last hollow pole just fit the spoke very well to allow free rotation. Now I had two copatible gear wheels they were fit at the bottom of these two shafts, and then glued. Now ready. The inner shaft with wheel is then put into the other hollow shaft. Good job!. Just ask me anyhing I will happily answer you.

Awesome.. i love a clever can do thinking

How many volt battery did you use and how do you control it

BATTERY CHOICE, DIRECTION AND STABILITY For the battery
I was using 3.7v nokia phone battery, it was giving an inpressing revolution per minute(rpm), this made me leave my battery problem and was battling with my blades and rotor head. During that time, my heli would lift the both landing skids above the ground but would not continue lifting. It would be in the air some centimetres for some seconds after which it would fall to either side. This was because of ground effect, it comes to play when your heli pushes air downward with a great force depending on the distance of the blade to the ground. When these air molecule hit the ground they push the blade upward, this pushes the whole heli upwards. But it cannot continue lifting because when the distance between the blade and the ground increases the upward force decreases, this was why my heli would fall to either side, my blade may not be cultivating aqual lift as they are hand made. I was inspire one day to leave my blade and rotor head and increase my voltage, I was very afraid of this because I do not have 1.5v battery for series connection but I had another 3.7v battery. I made up my mind to combine the two batteries, if my motor will burn then let it burn. I tested with timidity, my heli spun up into the air with great speed,,,,, haaahhaa that was realy lovely wow. So I used 7.4v battery.
For the direction
For the direction
In fixed pitch helicopters, the tail rotor is always there to counter toque created by the directional spining of the main rotor. This is why the tail motor is always horizontal, the tail blades are inclined to produce thrust in opposit direction to the direction the fuselede would spine without tail motor. This makes the heli fully stable. If on the ground it simply cnnot lift without tail motor and if on the air, and the tail motor stops for any reason it will simply crash.
But here in coaxial
Two blades are made to spine in opposite direction, one counters the toque of the other, this makes it fully stable even without tail motor. But my heli has tail motor, it is for direction. While the up and down movement is controled by the increse and decrease in speed of the main blade, the forward movement is initated by the tail motor. Here in my system, the tail motor is placed vertically to prduce downward thrust, this lifts the tail boom and causes forward motion. Then for the direction I inclined one of my main blades above the other, one have angle of attack greater than the other, this makes the fuselege to spine gradually, this is fully countered by inclining the tail blade to produce downward thrust as it spines in opposite direction to the direction of the main blade. The tail I made to spine at equilibrium, below which the helli rotates gradually and is stabilized by increasing to equilibrium. When tail motor speed is increased above aquilibrium the tail boom rises and the heli flies forward......very complicated right..no you will ge to understand it better as we go. Ask me anything I will answer you.
Feel free to call me 07088713141
click here https://www.nairaland.com/5032212/how-built-rc-helicopter-home#76053689 to see my photo Gallary

PHOTO SHOWING TAIL MOTOR IN ACTION My tail motor at work

Pls let me see the type of motor you use

MAIN BODY SETUP
the main body is a strong hard material used to mount the other components. Here in my setup, I used the circuit board for my main body. A circuit board possess good features that make me chose it for my buiding. The board is strong and light weight.
Firstly
the board is cut into a rectangle of desirable dimension, for my heli, I used 4cm by 8cm and is very good. Now, to determine the center of that board, this is important, I drew two diagonals running from one angle of the board to opposite. The two diagonal intersects at a point, this point is the centre, now a hole is drilled on it, just to fit your hollow tube. Your tube can be plastic or stainless, for me I used a radio pole of bigger diameter, this makes my two shafts rotate freely in the stainless tube. Now the stainless tube is mounted to the hole drilled on the main body and glued or epoxised. If one is building a fixed pitch type, then you will now have to put your shaft with the gear wheel into the tube to mark the point to drill for your motor. The hole should bo wide enough and lenghty to allow adjustment of the motor. Fit the shaft gear very well (not too tight, not too loose). When this is done, the motor is then put into the hole, adjusted to fit the shaft gear and then mounted on that position with the motor fit.
but here in coaxial
the system is completely different and look complex but not complicated. This is because, the coaxial heli has the pinion gear, the main gear and the inter intermidiate gear, this makes it hard to mark the points where the intermidiate gears will be placed to fit the main gear, the pinion and the othe intermidiate gear. I tried with just hand marking but it did not work for once, it was either too tight, too lose or even away from contact. But I later thought out a method I used and it work on the first trial. This methode, I will be posting about in my next post. Below you can see the motors I used. Just ask me anything.

FOR STRENTH
a circuit board cut to the axact dimension of the space between the motor and the stainless tube is put in between and glued together. This is for no other reason than to make the motor and the stailess tube stronger.

Hm...

GEAR SETUP
setting pinion gear to fit main gear is easy in fixed pitch helicopters, but not that easy in coaxial helicopterS, it may not be a work for rc companies. Because I tried with hand-marking the points to drill on my main body to make my pinion, main and intermediate gear fit one another very well, but did not come out with a positive result. This made me think out a method I used and it worked on the first trial.
here is how
I first found what I call carbon foam, you will see it in the photoes below. It is the weightless material found in newly bought electronics, I am sorry I don't know the name. It is cut to be of same dimension with the main body or bigger but not smaller.
Then I found a cardboard pepper and cut to the exact dimension of my main body. On this cut cardboard, two diagonals are drawn, the point of intersection is the centre.
Now the cardboard pepper with the drawn lines is pasted on the carbon foam with the exact dimension.
We are almost through, on the centre, I placed the main gear wheel without the shaft, use a pin or nail that fit the exact diameter of my gear wheel to fasten the wheel.
Now bring the intermediate gears, make them face up, the part with a sub-gear face up. Make the teeths of the intermediate gear fit themselves and the main gear as well.
fasten them with your pin or nail as well.
Bring the pinion gear to one of the intermediate gears, make it fit and fasten.
NOTE
The gear wheels should not be too tight or too lose, just ok to allow free movement.
Then remove all the pins and gear carefully. Remove the cardboard and mark the points where the nails made holes on the cardboard.
Paste the cardboard on the main body, mark the ponts on the main body and drill. Good job! Below you can see the main gear, pinion gear and intermediate gear. Just ask me anything.
Click here https://www.nairaland.com/5032212/how-built-rc-helicopter-home#76053689 to see my photo Gallary.
Feel free to call me 07088713141

Nice work! I will do something like this in the future.

A PHOTO WORTH MORE THAN a thousand words

CONTINUATION

NOW CONTINUEING...
I just paste the cardboard on my main body, marked the ponts and drilled.
I made the holes for my intermediate gears to be the exact diameter of the pins I used to hold them.
Then, putting the wheels on the pins that has been glued to my main body. This time the intermediate gears will be one faced up and the other faced down.
This is made so that one will hook one main gear and the other will hook the other main gear.
I inserted the motor gear wheel and it perfectly hooked the intermediate gear.
Now, stopers are used to stop the wheels from moving up and down.
Rotate the wheels, they should be rotating freely.
See the second and third photoes, there is a difference.
The last photo shows my gear wheels in contact.
NOTE
A small spring was put into the shaft, this reduces the high friction the wheel may be producing with the main body. Also, it allows your main gear to hook the intermediate gear perfectly.
ASK Me Anything

VERY IMPORTANT
I ensured that my stainless tube is streight. If you dont have a spirit level, eye plum can be used. I used my eye to view streight or slanty.

BUILDING MY BLADES now......
I know most blades used in rc helicopters are plastic, but I cannot mould plastic plades with hand. This time I had to think about what other thing can serve as my blade. I thought about wood, yes it can work but not that easy to shape and it is somehow heavy to my heli. I thought about other materials but the best I could find was aluminiun roofing sheet, it is strong, maliable and light in weight. Now, using aluminiun roofing sheet as rc helicoppter blade existed only in my immerginary world, I had to make it come to reality.
The first thing I do when trying to bring something from my immerginary world to reality is drawing it. At least it can now be seen and touched by other people not only me.
Now, I studied helicopter blades and understood the work they do and how they do it.
I studied the mistakes I am liable to make while trying to make blades with hand, thus, avoiding them.
MY RESEARCH
Helicopter blades are the lift cariers in helicopters. Now, what are the features they have that make tham lift my helicopter?
According Sir Iseac Newton, Action and reaction are equal and opposite. This is why blades are curved, to push air downward thereby initiating lift as the equal and opposite reaction of the action of downward air push.
According to Bournoli's principle, fast moving fluid has a low pressure while slower moving fluid has a high pressure, remember air is a fluid. This is why some helicopter blades and airplane wings are shaped to have the top curved to longer length and the bottom a little bit steap.
Symetrical, semi-symetrical and flat-bottom are examples.
Having a rectangular blade, from head to tail, can fly a heli but with toque. Here the tips of the blades appear to be above the head. This is because, the head and the tip of the blade covers differnt distances in equal time interval, the tip cover longer distance thereby cultivating more lift, this makes the tipe appear above the head during flight.
T o avoid this, the blade tip can be inclined less than the head
OR build a trangle like blade, this is the type of blade I built.
Dreawing my Heli Blade
here we go....
Click here https://www.nairaland.com/5032212/how-built-rc-helicopter-home#76053689 to see my photo Gallary.
Feel free to call me 07088713141

CONTINUATION
We have just made four blades that are exactely the same. But they should not be like that, this because, the blade should be counter rotational, two in a direction, the other two in the other direction. See photoes following this first photo.

Finally....
The diagrams you saw are all drawn on a pepper, this is to clearify how it is drawn. Now, I drew this last diagram above on my alumuniun roofing sheet. Our new house is still new so left over roofing sheet I found around. After drawing it next is to cut it out, sand with sand pepper and bend for curve.
Everything is measured with meter rule, this to ensure the blades are equal.
I have my centre table with a curved edge, then I placed my blades on The curved part and bent. This is to ensure the blades have the same inclination.
one blade the prototype of the other.
My blade is balenced with the rotor head on a pivote, very very important. CLICK THE 2 BElOW FOR NEXT PAGE
OR CLICK HERE https://www.nairaland.com/5007329/how-built-rc-helicopter-home/1#76219258
feel free to call me 07088713141