Manned electric multicopter
Tuesday, November 1st, 2011Quadcopters are very popular these days, but one can also increase number of motors to a multicopter.
One can also make it big, like these Germans did. Simple, yet amazing.
Quadcopters are very popular these days, but one can also increase number of motors to a multicopter.
One can also make it big, like these Germans did. Simple, yet amazing.
Very early this year, I started another(!) project. This is a webbased tool for everyone RC-interested which crashed and are in need of parts. Let’s be honest, we all crash and need parts. Which makes me believe this is a good project.
RC Part Finder.com is a click’n'buy service which let’s you find accurate and cheap(est) part for your vehicle. At this moment, anyone can register and add blueprints and start helping. I don’t earn any money on this, actually I loose some due to web hotel and data transfer. My goal nevertheless to make a useful tool for everyone at the cost of nothing.
After I sold my Team Losi Mini Rock Crawler I wanted another one, but a larger one with more capabilities. XR10 was released recently and I managed to get it pretty cheap ($240+Shipping+VAT) from Ebay.
The vehicle provide motors on axial, waterproof receiver box and independent motor control. This is where the signal control comes in.
Before I could start controlling signals, I had to modify my Traxxas 2.4 TQ. By following these steps found on Traxxas forums I were able to transform my 2ch transmitter into 5 channels.
Now when I had more channels I were able to use my transmitter to select which motor to run. This was done by routing the signals through an Arduino Nano as shown in picture below.
| From |
Here is the code I wrote for controlling the signal routing. Thanks to Servo.h library, my code became very simple and easy to understand.
the
Servo FRONT;
Servo BACK;
int throttlePulse,controlPulse;
const int throttlePin = 2;
const int controlPin = 3;
const int frontPin = 4;
const int backPin = 5;
void setup()
{
Serial.begin(9600);
pinMode(throttlePin,INPUT);
pinMode(controlPin,INPUT);
FRONT.attach(frontPin);
BACK.attach(backPin);
}
void loop()
{
throttlePulse = pulseIn(throttlePin,HIGH);
controlPulse = pulseIn(controlPin,HIGH);
if (controlPulse > 1700)
{
FRONT.writeMicroseconds(1500); //put ESC in neutral position
}
else
{
FRONT.writeMicroseconds(throttlePulse); //send signal to front ESC
}
if (controlPulse < 1300)
{
BACK.writeMicroseconds(1450); //put ESC in neutral position
}
else
{
BACK.writeMicroseconds(throttlePulse); //send signal to rear ESC
}
}
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| XR10 |
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| Home made tracked robot |
After my friend Jonny bought himself a flying wing by robbe when all my aicrafts were grounded. I speculated on how quick I could build my own. I already had a small brushed motor with speed controlled form an old MS hornet (heli) by MS Composit. Two $2 servoes, $16 DSM2 receiver and 2S 800mAh LiPo batteries I had laying.
Later that day I sat down with some 6mm depron and started cutting. I cutted one side of the wing first to make sure it was proper. Then i copied it onto another piece and glued them togheter with UHU and CA. A carbon list was installed for stiffness. To get buoyancy and more stiffness I chose to install some addional 50mm wide 6mm depron on leading edge of the wing. Known as KF-airfoil KFM-2.
Rudders were cut 30mm wide and some fin stabilators were added to the sides. The heavy yet small motor had to be installed closer to the front than first expected to make CG right.
CG were found using info from this site. and image.
I carved the batterydepartment throught the front to make the plane more areodynamic.
The whole thing landed on 168g included battery with an wingspan of 690mm.
The making of the plane took only one hour! Installing the rest and aerodynamic tuning for all the components was a bit longer.
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| Scratchbuilt wing |
Here is another project with it`s story for you.
I`we flown RC helicopters for around three years now and only electric. We all know batteries tend to get worn out, which is what who has happened to many of my batteries. They don`t have the same punch as they had, which is essential for good 3D flying. Even tho they are bad for 3D they can still be used for low-amps applications, such as scale flying.
Therefore I`we decided to get myself an scale body for one of my Align T-rex 450 helis, the oldest in fact. At first I bought a Airwolf body, but I didn`t really want an Airwolf and it did miss the tail with retracts. Comanche on the other hand has always impressed me, being «the best» helicopter around with a very long development period.
The build process started by figuring out what scale the heli would become for a T-rex 450. If I recall correctly the 450 has a blade with of 70cm and RAH-66 has 11,9meters. This results in a scale of 1:17. From here I calculate 1:17 length of 13.20m (without gun barrel).
There are very few good pictures of this helicopter from all angles on the internet, but I were able to calculate the tail to be tilted 15 degrees. I also had to do allot of testing of bottom plate and the lower sides to make it scale looking. After the bottom was finish I used a paper-piece and draw the upper body. After I cutting the paper piece out it was easy to make a similar in 6mm depron.
Update #1
Retracts and penta head installed, but the retracts were only made for the heli and battery weight. When adding five blades to the head the retracts failed under take off. When I saw the heli was about to come to one side I accelerated it to prevent blades for hitting the ground. My attempt failed and the comanche body were damaged.
After this failure I had three things to straiten up before the fuselage was perfect.
I have now thrown away (in the trash) the heli and will not build another one. Not this season at least.
Images
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| Comanche RAH-66 |
First video
After crashing my first F-22, I decided to build another one, but better and more scale looking. By downloading one of Steve Shumate`s creations I managed to build quite a nice plane.
It has same setup as last my first build, but is slightly smaller. I even gave it a better paint job, take a look in my gallery.
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| F-22 Raptor v2 |
So I decided to make something with RC-servos using the Arduino board and the sensor shield which I recently purchased.
I went ahead figuring out how to send arrow signals from my computer to Arduino using USB interface.
Using void setup() { Serial.begin(9600); } on Arduino and screen /dev/ttyUSB0 9600 on my computer, I managed to send commands back and forth. I hooked up the standard servo library and write some code before I mounted the Arduino board on my mini rock crawler. I now had a computer controlled car. Because of Arduino`s simple interface I had it all up and running around an hour. Check the small video and code below.
You can view and or use the code as you like below. (Sorry about the indention, WordPress messes it up).
//
// OBJ
//
Servo servo1;
Servo servo2;
// VARS
int readByte;
int servo1Angle = 90; //default servo angle
int servo2Angle = 90;
int minPulse = 700; // minimum servo position
int maxPulse = 2300; // maximum servo position
void setup()
{
servo1.attach(2, minPulse, maxPulse); //connect servo
servo2.attach(3, minPulse, maxPulse);
Serial.begin(9600); // start serial
Serial.println(“Ready\n”);
}
void loop()
{
if (Serial.available() > 1) // procced when two bytes is avaiable
{
readByte; = Serial.read(); //read first byte
if (readByte; == 91)
{
readByte; = Serial.read(); //read second byte to determine arrow type
if (readByte; == 65 && servo1Angle <= 180) //UP
{
servo1Angle += 5;
}
else if(readByte; == 66 && servo1Angle >= 0) //DOWN
{
servo1Angle -= 5;
}
else if(readByte; == 67 && servo2Angle <= 180) //RIGHT
{
servo2Angle += 5;
}
else if(readByte; == 68 && servo2Angle >= 0) //LEFT
{
servo2Angle -= 5;
}
}
}
// set servo positions
servo1.write(servo1Angle);
servo2.write(servo2Angle);
delay(15);
}
After running this motor to hard outside, I managed to burn the motor. You can see pictures of the “burnt” motor in the gallery below.
First of all I opened the motor to take a look noticing protective isolation layer on the copper were melted. Not so strange, because when I approaced the motor after the plane fell from the sky, it was insane hot.
Before removing all wire I measured the wire diameter to 0,30mm. I found this king of wire inside very small tranformators in a computer power supply.
By using this picutre, found on this page. I was able to re wound the motor.
I actually did wound all the poles at the same time, well, one by one, but all three wires were in use, if you follow.
After finish wounding I had to connect wires together to make only three wires, brushless motor has three out wires.
Since it`s a pretty fast motor I made a delta hookup, but I did a mistake at first. This motor should have around 195mOhm per 14-turn, maybe I did not mention it is a 14-turn motor. Which means each pole (there are nine here) needs 14 turns of isolated copper wire and in a small motor like this one, it`s not that easy. Anyway, by hooking up wrong end`s I broke a ESC of mine ($10) so I had to buy another one.
The motor works just great now and I might add a video later.
Gallery
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| Fixing brushless motor |