Quadrotor Help

Started by rachit, March 30, 2010, 10:38:18 AM

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rachit

Hi

I am a student trying to build a quad rotor as a project.
I have made the basic structure of the quad rotor from aluminum approximately weighing 130gm( only the hub and the rods). I am not being able to decide on which motor to use. I've seen 2 motor specs (EMAX2205 and CF2822) but am not sure whether they will be able to generate enough torque and the necessary RPM.
I've 2 types of props with me now as spares- GWS EP1060(10X6) and EP0843. Are such propellers suitable for such a model? If not could someone please specify the suitable propeller.
Also, m not aiming for autonomous flight so is a micro controller necessary for the quad or would simple ESC with reciever combination do the job.( sry for such a Q, this is my first RC project).
Does anyone have any other suggestions for building a quad rotor?
Thanks.

anwar

#1
Instead of specific answers, here are some general guidelines you can build upon.

1) Suitability of motor :  This is actually a combination of motor, ESC and prop (and even the lipo).  You have to figure out your all up weight (which includes motors, battery et al), and find out the wattage needed to lift your whole setup.  I have no experience with these, but since 4 of them are sharing the load, you can consider an overall 3x wattage of one motor to see how much weight your setup can lift (the rest 1x is for margin for error).  There are recommended props for each motor, please look at the data sheets.  If you use the wrong prop, you will draw too much load (amps), and that will cause some part to give up (burn up, to be precise).  Please read up on motor selection and amp ratings here, there are many threads.  Then find the specs (ie data-sheets) for the motors your have, and you will get a fair idea of what will work together.

2) If you do not want a complicated mC setup, then the design posted here would be a good start :

http://www.rcindia.org/self-designed-diy-and-college-projects/quad-rotor/

I just received the parts to build one (as our club wants to have one), but with many things to build and some personal stuff that it taking a lot of time, I am not sure when I will get this done.
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rachit

I looked up the chart for EMAX CF2822 and the recomended props are all APCs. What is the difference between APC and GWS props?
I googled the question but all i got was that most GWS props are slow flyer props. Could someone please explain which props are suitable for which all models.
Thanks.

anwar

What you should look at is the dimensions of the prop, and not the manufacturer.  The same manufacturer may have different types of props of the same dia + pitch (stiffness, material etc being variables). Among the common APC and GWS props, I have seen that GWS is generally flexible, which allows for better crash handling, at the expense of some thrust/performance (I believe).

Again, you should look at the pitch + dia (and not the manufacturer) as the big variable.
Hangar : Please see my introduction.
RC India forum and me : About this forum.

rachit

How do i find out the wattage of one motor? (P=VI) should i take the max values of V and I that the motor can operate on? Also the motors recommended prop size is 10X5 so is it necessary to use that or is it OK to experiment with a 10X6 prop?

anwar

#5
The wattage for each motor is usually specified in the specs (data sheet).

One size difference is usually sort of safe to experiment with, but be careful about taking it slow and steady.  Run it at  medium high throttle for a little while (some seconds), and check the temperature of components. Gradually try higher throttles.

Having a wattmeter would be ideal.
Hangar : Please see my introduction.
RC India forum and me : About this forum.

pankaj

overloading(using more pitch than recommended) can burn your ESC  or motor .

but for fraction of time (seconds >:D) you can overload ESC or motor.


rachit

#7
Thanks got the wattage, 150W for the CF2822.
Pankaj i saw your blog, what is the use of the gyros here, do the mixers need such an input?
can you tell me which gyros you are using? can one do without it? I don't need any kind of autonomous reaction by the quad rotor ( i want each and every moment to come by my receiver). A basic quad rotor i.e with altitude, forward ,backward, right and left control.
Are you using one 3S LiPo for each motor?
Thanks

pankaj

#8
basic work of gyros is making quad stable,

when gyro is not getting any signal(to varry speed)from rx it will uppose the movement (on a paticular axis) by providing +ve or -ve signal to ESC and thus controlling the motor.
but when a signal comes from the rx it let pass that signal to esc.so we can varry the speeds manually

and we do not need very high sensitivity in gyro .50 to 100 degrees is sufficient.(anwar sir has discussed that in some thread).

now i m using the microcontroller so i m searching for the gyro suitable for it.
i will be posting the microcontroller circuit details by tomorrow.




Gaurav

Please not if you're not using a microcontroller setup you will have to learn how to fly an R/C helicopter otherwise you may risk crashing your quadcopter... and May I know is it a college project? If so which college are you from?

swapnil5775

okay i got it. tell me. If anyne Specialist in Quadcopter here then please tell em ATMEL AT89c51 Controller is okay for this ? can we built this quadcopter by using it ?  Please tell me . ii have to make decision for this.

I wanna Make Quadcopter for my College project. i am from gujarat Noble engg. college. Very Small Not more functional Quad i wanna Make but can i use Atmel AT89C51 for this one. please tell me.

souravnyk

Hi...!!! I am a final year student and i want to build a quadcopter for my final year project. Can anyone help me?? What should i do and to not. If possible can anyone tell about it from its basics.