Starter's radio

Started by iamahuman, April 16, 2010, 11:59:24 AM

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iamahuman

I am going to start making a rc car.I want to move on to planes later.I am making the car for fun and experience.
I am in Bangalore and have no experience in building any that is radio controlled.The reason for that is I am 14 years old.
I have read a lot about a website called rc dhamaka and I will be buying my equipment from them.This is what I will be buying
anwa/Airtronics MX-3FG FHSS 2.4 GHz Radio w/4 Channel Receiver                                  
9"extension                                       
Front Wheel Steering Arm & Mount Set 40mm                 
EMAX CF 2812   motor                
EMAX ECS 7A   Electronic speed control         
240V 2-3 Cell Li-Po Battery Charger         
20c 2300mAh-2Cell 7.4V
I will take care of the chassis on my own.I am trying to figure out a way to steer the car with a simple mechanism using servo controllers.
I will buy the necessary servo controllers too.
Is there anything else I need to buy?
And also,I need someone to guide me through the process of building this car.
I don't want it to have a body nor any suspension.
I will be using it as an indoor racer.
If there is a better radio system suited for beginners,please let me know.            
"Chuck Norris once overcharged a lipo. Thank him for the Sun."

SSC LCG Slash 4x4.
JQ THE eCar.

iamahuman

Some more things I need to know are can I buy the axles or should I have them made for me?
What do I do about the tires?
"Chuck Norris once overcharged a lipo. Thank him for the Sun."

SSC LCG Slash 4x4.
JQ THE eCar.

vinay

The radio you are buying cannot be used for airplanes. also Iam not sure you can use that motor for cars. I think brushless inrunners are more suited for cars? Or atleast outrunners in the shape of inrunners? wait for more answers.

anwar

Since you are planning to enjoy building from scratch, you should be able to get away with most of it, except for the major issues noted below (others please add, in case I missed anything).

1. If want to get into planes later, buy an airplane radio and use it for the car also. The other way does not work, as Vinay noted.

2. Get a 20A ESC.

3. You will need some kind of gear reduction system to reduce the motor rpm to the car level.  Be very careful initially with it, and apply throttle gradually, watching/feeling the temperature on the motor, ESC and the batter.

You will have to jig up something to move the tyres using the servo.  I hope you have fun trying to design and build that, as compared to getting something off the shelf.

Looking forward to see your care here soon !

Hangar : Please see my introduction.
RC India forum and me : About this forum.

iamahuman

Well,so could you tell me which radio to buy and anything else I should change or buy?
and also,could you tell me why I should buy a 20A ESC?
My budget hovers around Rs10,000-12,000.
Can anyone give me a simple mechanism for steering.
By the way,for the gear reduction,I have an idea.
What I will be doing is putting a gear on the axle(rear)behind the wheel and a smaller gear on the shaft of the motor.
Also,if there are anymore suggestions about what I should do or buy,please let me know.
And thanks a lot for such a quick response ,both Vinay and Anwar.
"Chuck Norris once overcharged a lipo. Thank him for the Sun."

SSC LCG Slash 4x4.
JQ THE eCar.

anwar

Radio is the big barrier for entry in RC.  There are many threads here on options, one that comes to mind is from RCForAll. 

ESC has to match the motors expected load (current in amps), and the motor you picked had a peak amps rating of 16A.  So the ESC has to be slightly higher than that (18A or 20A are available with RCD, I believe).  You can consider the new combos from RCDhamaka that are nicely priced; they include a motor, ESC and prop (you can use that prop later when you get into planes).

As for the reduction gears, your thought process seems right, although the ratios of gears will have to thought out better.  You can buy "pinion gears" that will fit the motor shaft well (although I have not looked for the in local stores for availability).

Designing a steering mechanism is easy, fabricating the same would be the interesting part.  Basically, a servo arm moves to either side, you can extend that movement with additional rods/sticks to move the wheels which have to be mounted on some kind of pivot.
Hangar : Please see my introduction.
RC India forum and me : About this forum.

vinay


iamahuman

I stay near rajajinagar 1st block
"Chuck Norris once overcharged a lipo. Thank him for the Sun."

SSC LCG Slash 4x4.
JQ THE eCar.

iamahuman

I am buying almost everything from rc dhamaka
Can anyone give me some suggestions as to which product I should buy.
Like the inrunner motor.
But with a simple gear system with one gear on the shaft and the other on the axle,can't I use an outrunner motor?
It gives lot more torque and either way all those revs will be useless unless I can put that power down on the road.
That maens I need traction to make use of my inrunner which turns at really high rpms.
"Chuck Norris once overcharged a lipo. Thank him for the Sun."

SSC LCG Slash 4x4.
JQ THE eCar.

iamahuman

"Chuck Norris once overcharged a lipo. Thank him for the Sun."

SSC LCG Slash 4x4.
JQ THE eCar.

iamahuman

anybody who is online,please help me.

I will be out of Bangalore from the 19th till the 28th.In that time span ,I would like to order the things I need to make my car.So ,can anybody tell me what else I will have to buy to make it complete.If there are any suggestions,changes,new products I should buy,please let me know.I need an inventory so that I can order all that I need and come back and assemble my car and race it.
This is what I will be buying
receiver,transmitter   Sanwa/Airtronics MX-3FG FHSS 2.4 GHz Radio w/4 Channel Receiver                                 
9"extension                                       
Front Wheel Steering Arm & Mount Set 40mm                 
EMAX CF 2812   motor                
EMAX ECS 18A   Electronic speed control         
240V 2-3 Cell Li-Po Battery Charger         
20c 2300mAh-2Cell 7.4V
I still have a few doubts.How am I going to control my motor?Will the circuit be something like the receiver connected to the steering servo on one channel and the ESC connected to the motor on another channel along with the battery connected to the receiver?Also,I read about throttle servos.Are they for nitro powered vehicles or are they for electric vehicles?Some books I read say that the throttle servo can act as a brake too.The only possible way I can think of doing this is to reverse the direction of flow of current and make the motor spin in reverse.Also,somebody ,please give me a simple steering mechanism to put on the car.I will try to incorporate a suspension.
   
I was told by anwar and vinay to change my radio and motor and esc.
I changed the esc but can you tell me more for the radio and the motor.
Will the car not work properly with an outrunner or is the inrunner useful because I can attach a gearbox and get more control over the power?I will buy the servo for the steering but do I need one for the motor.
I want to keep the car as simple as I can.
      

"Chuck Norris once overcharged a lipo. Thank him for the Sun."

SSC LCG Slash 4x4.
JQ THE eCar.

anwar

#11
The ESC (not ECS) will control the speed of the motor, and the ESC is driven by the control signal from the receiver (which in turn is transmitted from the radio).

There are a few things you should note.  Most likely, no one here has done the exact same thing you are trying to do :)  So there is an element of unknown  or uncertainty, and that is what makes these projects interesting.  The other important thing is, you need to clarify what your future intentions are.  If you are sticking to cars, that radio is good.  If your future looks more like airplane flying, then that radio is not the right one.  This is what Vinay and myself have been trying to say.

Throttle servos are for nitro models (from what I know, I am not a car person.. yet!). In electric cars, which is what you are trying to build, reverse travel is normally achieved by ESCs that support a "reverse mode", which is done by changing how current is supplied to the motor.  ESCs have a brake function too.

Also, if you will be more into planes in the future, out-runners would serve you better. So make these decisions, and move forward :thumbsup: 
Hangar : Please see my introduction.
RC India forum and me : About this forum.

sriharishine

Hi,

Please check the attached image for making Steering System using servo for your Electric RC car...

- Srihari

anwar

Good illustration. Needless to say... the blue colored poles/rods/posts need to fixed on the chassis (and the servo too), the rest should be free to move.

Now building something like that from scratch would be the challenge (and the reward!) :thumbsup:
Hangar : Please see my introduction.
RC India forum and me : About this forum.

vinay

TO make it simple, you can actually buy a toy car, not the RC ones, the cheap 30 to 40 rs ones that are sold for children below 3 years on the streets, and then modd it, this gives you wheels, chasis, body etc. You can then modify this to fit your rc stuff inside. Just my 2 cents idea. If you want to build your own RC car body/wheels etc, then it becomes more interesting but very challenging .

sriharishine

One more complex Steering System based on servo, here two servo are used and it is suitable for buggy... Check the image attached.

vinay

#16
Generally very high torque servos are used on car steering wheels, but that depends on your car size. Since I am not a CAR guy, this is the max I can go.

Regarding the radio, you can go for the RCForAll.in 6 channel radio or you can buy RDS8000 from RCDhamaka.com (a little expensive but good for beginners and medium budget situations) or you can consider the Hitec radios also but I dont have much knowledge abt it.

FOr ESC you need a bigger ones. since cars need high torque, they will be amp hungry since they usually run on low voltage(2S) lipos. so go for a min 18 amps or more. Regarding motors, buy the ones that are designed for cars as much as possible. But as you buy a motor, make sure you find a suitable gear system. IF you buy motor and then not find gears for that shaft size, it becomes a night mare.

YOu may wait for more replies as car experts start answering your queries.

sriharishine

Quote from: sriharishine on April 17, 2010, 12:50:29 PM
Hi,

Please check the attached image for making Steering System using servo for your Electric RC car...

- Srihari

For this setup, You can buy the set from http://www.amainhobbies.com/product_info.php/products_id/158391/n/Traxxas-Steering-Bellcrank-Set

I think all the parts in the above link is enough to make a servo based steering.

- Srihari

iamahuman

Hey guys,
Thanks a lot.Your replies were very helpful and extremely useful.Now, I have a really good idea as to what I should and should not do.
I think I will stick to this radio and the outrunner and buy a different one for the aircraft.
And the ECS was a spelling error.sorry for that.
But really,you people are wonderful ,all of you and I am really grateful.
"Chuck Norris once overcharged a lipo. Thank him for the Sun."

SSC LCG Slash 4x4.
JQ THE eCar.