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-   -   A.B.S. (https://www.rctech.net/forum/nitro-road/90379-b-s.html)

j3di 11-12-2005 12:36 PM

A.B.S.
 
How many of you guys use ABS on their cars? Ad do you find the system efficent??




Luke

stefan 11-12-2005 12:44 PM

I did use it when I started but it was hard on the gas servo. After the second one gave up I quit using it.

j3di 11-12-2005 12:54 PM

So does it actually stress the servo?

Luke

AndyT © 11-12-2005 04:31 PM

Apparently its quite harsh on the servo`s due to the rapid pulsing and constant workload its putting on the servos.

ogreasurada 11-12-2005 05:22 PM

I think ABS function is more helpful in electric cars to give them a smooth run and its done with ESC and motor which is mostly electrical. For gas cars since usually the break pads and disc are already set to drag slowly when the servo pulls the linkage to create smooth breaking action without locking the wheels causing spinning. If ABS is used for gas cars, then the linkage will need to be set for stronger break, and the servo needs high reaction speeds to compensate with the loss of breaking power during the servo's backing period and smoother drag. In this case, not only the break pads will wear faster, it puts a lot more loads on the servos. However, due to the design of common 1/8 and 1/10 cars, the break and throttle are connected to the same servo, unlike 1/5 scale cars where seperate servos are used, this may cause unstable vibration to the throttle, and so much energy will be lost during the larger motion due to the relatively long breaking linkage. And todays servo and radio settings and function are still far away form creating a smooth (un-noticable) ABS action (Most radios ABS frequency settings can only go up to 20/sec *rough guess*, in geometry in order to make a smooth (breaking) curve you need far more dots than 20). So the traditional breaking system is more suitable to function a smooth break for the smaller scale gas cars.

This is just my little thought on the efficiency on using ABS on gas cars. And please excuse my poor writing. :sweat:

rcfoolz 11-12-2005 05:39 PM

Many points well spoken. I do use it though when running a one-way on a very large track due to the higher speeds. I don't look for it to fully stop the car, but with the flip of a toggle, I can turn it off like when comming into the pits. At full throttle, I use it to give the car some "drag" in tight corners, but other corners I don't want the drag. As for servo's, yes, I have had 2 Futaba S9451's go out in 2 races. both were a couple years old, and until I read your post, I was unsure why they failed. (Thank You)

I now run a coreless digital servo and my radio is an overseas version that is not yet/ and will not be made available to the US market and it has an adjustable pulse rate of 6-60 pulses per second. With the digital servo being used now, the transit speed is .7 at 7.2v and the servo is still only able to pulse at the rate of about 40-45bps with a throw of 5deg. When the radio is turned up more than 40bps, it just makes the servo buzz. I think the Radio's can handle the speed, its the Servo's that cannot. Anti-lock breaks on cars now have a pulse rates of 200+bpm I believe.

Its still cool to watch the car break with the ABS when people are watching that cannot believe you can get ABS on an R/C car.


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