Pisty

hey, people heres a bit about myself as this is my first post.

I'm 18 years old and used 2 be into r/c cars when i was 13-16 until i grew out of it and got my licence. i sold all of my stuff except for my radio. now that i have alot more cash and in need of a hobby i am looking at building a full scale r/c car.

i have a fair idea of what sort of car i need:
*rwd to elimate torque steer
*power steering
*automatic
*power brakes

now i have done a bit of research and have got the throttle worked out since its the same setup as smaller scale cars, but can't work out how to get the brakes and steering fully functional.

brakes: i need something that can apply alot of pressure but not 2 slowly. is there some way 2 modify the brake pump so it uses the engines power to press the brake in?

steering: wont require as much torque as the brake but i dont want to buy any more servos for this project. mine have 4kg of torque but for reliability i only want to use 2 kg.

please give me your advice!!

jimbo1890

"Grew out of it"????????

what are you trying to say?????

some people may take offence at that[>:][>:]

mabe try some compressed air actuators and rams

I have seen this done before, not sure where though

Cyberfyn

We had a TV series in the UK a few years back where teams would make RC cars from old scrappers, beef em up with weapons and then put them in the ring of death! I seem to remember that some used the electric window motor and mechanism to control the steering and some linear actuators for the controls.

Pretty cool but none of them seemed to work very well, But that might of been becaus the competitors had no RC experience!

Ian F.

Pisty

heheh nah i dont think i will put weapons on this thing. it will be more of a "what the...." machine.

does anybody know if it it posible to take apart a cheapo servo, desolder the motor and hook up something more beefy? i would still have the part that recognises the servo arms position but it would be not fixed 2 the motor but fixed 2 the wheel.

also one other question, will i have 2 use the third channel for braking or is there some way 2 hook 2 servos up 2 the one channel.

Cyberfyn

You can get a Y lead to connect two servos to the same receiver channel. Obviously both would either move in the same direction or oposite depending on lead polarity. As for using the potentiometer from a servo to control a larger motor. Duno! Obviously you'd need an amp of some sort to boost the power. But there are custom robotic servos avaiable with the torque you would require. Infact some of the bigger RC ones churn out 20-30 kilos of turning power. With the right levers and servo savers I'm sure the'd do the job.

Ian F.

Pisty

glad u understood what i meant. i have just taken apart a futaba s3003(basic) and hooked up a more torqey motor but i think its going to need heaps more amps 2 be useful.

sorry, i still have more questions but am really appreciative of the response

would it be ok to run 2 or 3 times more amps through my reciever or will it fry? judging by the thickness of the wires i can guess the answer 2 this but it would be easier to use a bigger reciever battery than using an amp. On this same note do you also know what the ampage limit of the servo circuitry is? i guess if i get stuck i'll throw a few hundred bucks into a servo amp, and beefed up servo.

original.mb

cyberfyn

i remember that programme well

JRexA

You could look at the Tonegawa Servos.

They can run on 12V, making them capable of running directly of the car bettery.

The RC model PS-050 produces 91.5kg/cm(1271oz/in) at 8.4v, but it can handle 12v.
It should produce something like 130Kg/cm(1800oz/in) at 12v.

The Robot Servo SPS-105 produces 380kg/cm or 190kg/cm depending on speed
It needs 12v and 9 amps.

daytona7

There was some video made in California if I'm not mistaken of a 1:1 RC car. Showed how they hooked up the servos and some footage of it in action. Might still have a copy.

Cyberfyn

I'm using a 3300mah NimH 6.0v Receiver battery on my FG, But this is the limit on most receivers im afraid. Most state 4.8-6.0volts. Amps wise I'd not push it too far!

Ian F.

amitysanimal

I have this video saved on my puter but I have no idea how to send it. If you can explain how to send a video I will be more than happy to send it to you.

amitysanimal

madgti

You can host the video to www.rcpics.net and just drop the link here so we can all view it.

amitysanimal

http://www.rcpics.net/view_single.php?medid=50660 try this........if not do a search on www.rcpics.com for 1:1

amitysanimal

snooptalian

My Feedback: (7)

Why can't I ever get vids from RCpics to work? All I get when I click the video icon on that site is my computer chirping at me once and that's it, no vid, no mesages, nothing. Do I have some setting on my PC not set right or what?

madgti

snooop.

update your windows media player if your using windows.

daytona7

Thanks for posting it since I still have not found my copy. I hope this will give Pisty or anyone else a good idea on how to make a 1:1 RC.

BUGGIES_R_US

My ideas:

Steering:
You could take off the steeringwheel and attach a motor assembly that turns the wheel. Certain cars(american cars)have very easy steerings so thisshouldnt take much.
Maybe you could run a power invertor and use 120V motors.
You could also use Hi-Torque WINDSHIELD WIPER motors for this. They're powerful and cheap!

Brakes:
Hmm kinda tricky... What about a motor driven geared assembly kinda like what they used to use in old steam engines. Ration is turned into lateral movement. You could gear down the motor to get variable/precise braking. I imagine that with the right setup this could be fairly fast as well.

These are my "off the top of my head" ideas.. so sorry if they sound stupid lol

Ram

snooptalian

My Feedback: (7)

Thanks man. That fixed it.

madgti

Glad to help

Pisty

i just put 12v at 1 amp through my servo and smoked it. maybe it was the voltage but i dont want to destroy any more with trial and error. windscreen wiper motors would be sweet if i knew how to build a heavy duty circuit.

i looked into getting a Tonegawa industrial servo but prices for start at $500 USD[X(] which is way above my budget. If anybody spots a high torque servo for sale that can turn atleast 180 degrees and is compatible with futaba please tell me.

jimbo1890

Does the steering have to self centre if not use a standard servo to throw a couple of opposing microswitches sounds rather basic I know but at least you would get something running and then you could get fancy with an amplifier to deliver power to a wiper motor later. as for brakes use an air ram and solenoids it would give you plenty of braking force on the pedal.

Doahh

Ok Steering:

Just mount a servo there that can go 360+ degres

Breaks use a Hydroulic (sp?) or Pnumatic (sp?) actuator (sp?)

You can also get the refurbished tonewaga tone 050 servo for 65 bucks in america
http://www.vantec.com/ssps050.htm
The other one is 160$ repaired
http://www.vantec.com/ssps105.htm