nitrosportsandrunner

i have a rustler vxl. on 3s lipo it can get going pretty fast. its hard to come to a stop without spinning out, because it only has rear brakes.
i have a couple of spare servos kicking around, and a 3ch TQ radio. any ideas on how to use the servos to apply braking force to the front tires? mind you, it has to be a durable setup.

Kishon

No.

nitrosportsandrunner

i know what you mean. ive been staring at the problem for awhile...with no ideas.
i wish traxxas would make a kit to add front brakes. i think it would really improve the performace of the rustler/bandit/pede/slash.

Slo-V Flyer

You could try to mount some kind of "drum brake" style system. I'm picturing something where a servo on each front wheel/suspension arm somewhere, move a small "shoe" that presses against the inside of the front wheel with some amount of force, slowing the Rustler down quit fast. If you use the 2 position 3rd channel, you'd have basically what would be like ON and OFF... so you reach 50 mph and you want to slow down in a hurry? Flip the switch and your Rustler, depending on the brake strength, will slow right down...flip the switch back and release the brakes.

There are more ways but considering the lack of space and design to accommodate a proper front wheel braking system, you will have to rely on some custom work there.

nitrosportsandrunner

ha, i hadnt thought of a drum brake. i was looking at things trying to figure out a way to use some nitro drivetrain brake on the front wheels(all of which are disc brakes) but there is not really any room.
ill have to stare harder and think about this drum brake idea.

Slo-V Flyer

Yeah, I've had plenty of staring sessions with my R/C dreaming up stuff to do hahah.

Yeah disc brakes only would really fit in the 1/5th scale cars with the amount of space to work with. Drums brakes are also simpler.. you're just pushing against the wheel to slow it down.

nitrosportsandrunner

wow, i just had a light balb go off....
does anyone know of a nitro brake kit...where the rotor has a 14mm hex sized hole for the center? if so, i really think i could make a brake setup! if i could find a rotor that would fit onto the plastic 14mm hex(the wheel doesnt cover the whole hex) then i could mount a "piston" onto the steering knuckle. i could use some bikecycle brake lines(that would give me the flex i would need.) i just need a rotor that will fit!

andybenton

im seeing the same thing you are,

the only thing would be mounting the system on the a arm, but with some simple aluminum brakets, or something made from derlin, or even styrene...

but either way it could work, really...    how come no one has made this allready lol, it should be simple...

andybenton

ok i think ive found the one major hitch in all of this, (sorry you got my wheels turning)

when you turn the wheels it will add tension to the cable thus applying the brakes to one wheel.

if you can over come this issue, you can come up with a system that doesnt apply the brakes when you turn the wheels it would work.




i think if we had a nice high torque affordable servo you could use hydrolics from a small dirtbike or 4wheeler it would work, but the ammount of leverage needed to push the hydrolic cylinder is really quite high.


hydrolics solve the problem but i lack alot of the knowledge of how to engineer that small of a hydrolic set up

nitrosportsandrunner

i was thinking of using a brake line setup like you would fine on a bike. that way you can have extra line which can flex. on a bike, the actual brake line moves inside a flexable(yet firm) tube. the tube can be longer, thus allowing flex. i would have to mount both ends of the flexable tube, one end near the servo and the other end on one side of the caliper. the servo would move the metal line inside the flexable tube.

inside the caliper, i would need a spring which would try to push the pistion out toward the rotor. the servo would keep the pistion in the caliper(overcoming the springs force) and when the servo swings the other way the spring pushed the piston out to the rotor.
if the caliper is mounted on the bearing carrier(between the actual hub and the steering link) then it would always stay the same distance from the rotor(even when the wheel is turned), which would be mounted onto the 14mm hex(that gray thing that the wheel presses onto(it has the little slot for the pin on the backside))

also, because we are talking of using the 3rd channel on the radio...the brakes would be on/off. thus, we dont want the front braking force to be too strong, looking up the front tires all the time. we just need enough braking force to keep it from spinning out(and to slow down quicker) so i think a springs force on a pistion on a rotor would accomplish this.

Slo-V Flyer

I like this idea. Didn't think any rotors existed that could but slipped onto the hexes. The bike style brake line sounds possible.

This would be super cool to see set up/mocked up on a real 1/10th 2wd truck.

[8D]

Without using any electronic knowledge, I'd also suggest another idea, if the reverse speed/function was not so important, to go around the 3rd channel ON/OFF brake problem. What if you rig up the brake servo like a nitro in parallel with the ESC connection...as in when you hit reverse it would engage the brakes (as you said, using the spring to apply the actual force perhaps) proportionally, and when you hit forward, the servo simply turns harmlessly the other way. Only draw back MIGHT be that your reverse speed will suffer when you actually want to go backward, without a clever mechanical or electronic brake disengaging system.

Chris_RC

It is more trouble than its worth. The rustler was designed for speed runs, nothing else. Your best bet would be to add bushings to the front of the car to give the front wheels some resistence when runing, which would be like drag brake.

fourwheels0

My Feedback: (7)

very easy to do.
get a 4wd chassis and drivetrain.

nitrosportsandrunner

LOL, the guy whose quote is "brakes are overrated" commented on this thread!

i know that a 4wd chassis like a revo or a savage flux would have all the speed and 4 wheel brakes. but i dont have cash for either, and im kinda fond of the rusty vxl. its very tough, and easy to repair if i do manage to break something.

SyCo_VeNoM

get one of those $60 4x4 slash rollers off ebay
otherwise this is going to add alot of weight and make it way more difficult to repair.

here is probably the easiest way to keep it 2wd btw
get a set of the rustys rear axels and cvds slap some front diff on it that you can make fit, and fit a pad upto the shaft that you would normally hook a dogbone upto and set the rest up like the brake on a nitro. they drum brake idea is a nice idea but realistically there is not much room in the wheel well to fit the equipment, and anything you could rig up would break super easy, due to how tiny the parts would have to be, when you hit a bump with how fast you would be going.

nitrosportsandrunner

i do feel like my idea can work, but as you say, making it strong and durable would be super hard.

nitrosportsandrunner

rusty rear axles rub against the front A-arms. and the rear axle has a shorter spindle(the hole for the pin doesnt go past the bearing) so i dont see how that could work.

SyCo_VeNoM

ahh was just a thought I was going based on what I remember of my nephews pede seeing I know there quite similar

nitrosportsandrunner

yeh, it was worth a try.
i looked on ebay, and slash 4x4 rollers are going for more like $150. thats without tires or a body.

SyCo_VeNoM

wow did they go up in 2 weeks
I should have bought 3-4 and just re-sold them when I saw them for $70 - shocks
look up "traxxas slash platinum 4x4 chassis parts lot w/ diffs" $60 buyout its missing arms, CVD's, shocks, and some other parts but looks like the whole drive chains there.
So I'm guessing if you slapped on your rustys arms and parts you would need only front CVD and front cups.
BTW that is a guess based on what I read people do to the slash 4X4's I was originally going to buy a roller and make a 4wd pede out of it, but I ended up ordering an airplane instead (don't ask how I went from 4wd monster truck to airplane).

nitrosportsandrunner

hey i can see how you ended up with a plane.
i like my rusty alot, but last summer i had a parkzone slo-v. it was fun and easy to fly. i would like to get a HZ super cub(lipo edition) or mini super cub.

skippy7399

There's always someone knocking you down for trying something new isn't there? Hey I'm all for trying new ideas. Besides if this works I'd consider it for my 2wd Slash. I race a 4wd truggy and know the benefits of having front brakes. Have you thought of this, r/c jets use hydraulic brakes. If you were to use drive axles, since the Rustler just uses axle stubs, could there be some way to utilize a set up like they do? Just a thought. It might be heavy, I can't help but think it will be expensive.

Ken448

Simple solution.. put a gyro in it. Itll countersteer automatically then

SyCo_VeNoM

I bought a GWS E-STARTER for $35(free shipping) and flung a pile of electronics from hobbyking 2 tunigy 2200 mah 30c lipos, ESC and BL motor, 6channel 2.4ghz radio, for a total of $126 with EMS shipping for a grand total of $161. My budget I set was $160 so $1 aint a big deal to go over
Started from me seeing a video of a RC jet and me wanting one than asked in the jet forum and they said with no flying experience it would turn into a nice looking very expensive lawn dart, and said buy a starter plane and from reading ended up on the GWS seeing it was cheap, and from what I read an excellent starter plane

And skippy I didn't want to knock him down.
The ideas sound but there are some inherent issues with it that I don't see how they would be overcome. One is its size. You might be able to make it small enough but he also stated durable. Looking at a normal bikes brakes I cannot see how you can shrink that down to under half an inch, and keep it ability to actually stop. Looking at some of my RC's I would have less than a quarter of an inch to fit the pad, and assembly in. Seeing the pad would be I'm estimating 1/8th on an inch alone that would only be leaving another 1/8th on an inch for the full assembly. Second is the issue from turning and he brakes accidentally engaging that was mentioned. It will also be adding alot of weight onto the front of the vehicle that would lower its rear ends traction so essenitally it would probably greatly impact performance pretty drastically. And if you engage them enough chances are you will warp the inside of your rim from it grinding it and getting it quite hot while stopping, which will require rims to be changed a fair amount or cause the truck to shake when it starts going faster.

Its an interesting idea but in all truth not the most practical or cost effective solution, along with how many parts would have to be custom machined. For how much will be blown in parts with trial and error he could probably just buy damn nice 4wd vehicle brand new that would put the rustler to shame.

This is coming from someone that has blown a fair bit(well over $1000) in ideas that don't pan out well in the end.

nitrosportsandrunner

yeh, i thought about building a GWS flyer like you bought. the parkzone slo-v is a similar idea, large wing area with a stick body. the slo-v has a V tail tho. i had HZ drop module. it was alot of fun.
the amazing thing about the slo-v, was even tho it looked flimzy, it was tought. the landing gear, battery holder, prop and other parts would "give" in a rough landing so that nothing would break. i should never had sold that plane. its a really decent beginner plane for $100 RTR. i should have kept it and changed it over to brushless and lipo.