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Old 04-27-2014, 07:23 PM   #16
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There's really no point in mechanical brakes for a 4wd touring car, or a foam-tire pan car. Your goal is to get through the corner as close to full speed as possible.

Now on an F1 car, it would make sense. All your braking is done with the rear tires. Watch any 1:1 formula racing where someone has the brake bias set too strong at the rear, and you'll see the lock ups and skids.

FWIW, 1/8 to 1/5 scale onroad bikes can and usually do use a servo activated front brake, and it makes a huge difference. I had occasions where I would "endo" my Venom GP-1 if I wasn't careful.
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Old 04-27-2014, 09:10 PM   #17
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Motor brakes work fine for me and modulation can be set from the radio, if the radio allows for it. As Andrew said, bias may be an advantage with traditional brakes, but belt tension can accommodate that to some degree (if we're talking rubber banded TCs). The deceleration and braking zones are so short with these low mass cars, traditional brake theory is not fully applicable. Much of the deceleration is accomplished via tire scrubbing and it's hard to pass under braking on the tight tracks in the states. Exceptions may be large tracks with long braking zones. Even then though motor brakes are very effective in slowing the vehicle down.
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Old 04-27-2014, 09:12 PM   #18
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Quote:
Originally Posted by FrostyDude View Post
I have actually been thinking about taking something like a Nitro TC3 or a Nitro RS4 and replacing the engine with a brushless motor. Then use a 3 or 4 channel radio and use the radio to mix the channels of the speed control and brake servo.

I am going to have to do some research about that brake for 1/8 scale electric buggies that you mentioned.
I think it was Tekno RC Designs, but it was up to the builder to use electric or mechanical brakes.

You're probably on the right track with modifying a nitro car. With the TC3 or the RS4 you only have rear brakes.
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Old 04-27-2014, 09:25 PM   #19
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It should also be mentioned that the braking force is variable depending on the motor.

Lower turn motors with a stronger rotor have stronger brakes.
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Old 04-27-2014, 10:12 PM   #20
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I thought about that many times too. The problem is as already mentioned the low (and decreasing) mass of our cars. I doubt you could have brakes that would not lock up instantly (or almost) on a 13-something hundred grams sedan. Or at least not without some really smart footwork so to speak.

Real cars (including F1) are moving towards a technology we already have. That is regenerative brakes with electric motors in each wheel that take over the (mechanical) brake function. The only technology we lag behind is the individual wheel motors. I think we'll see that within less than a decade at the current technology advance pace, and then it will be a non issue. We'll have individual motors for each wheel and therefore individual brakes. Diffs, belts and shafts will be redundant too, so there you go. We live really exciting times. Enjoy.
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Old 04-28-2014, 08:31 AM   #21
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They do this on 1/5 scale sedan vut they quite a bit bigger and heavier.
For 1/10 I doubt it would work though due to thw added complexity and weight. It would also be difficult to dial all four corners in as they could all have varied traction, thus causing lockups in one corner and not the other.
Nitro car brakes are pretty simple but they seem to work decently.
Until they get hot. Real race brakes don't work at all til they get hot heh.
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Old 04-28-2014, 08:31 AM   #22
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I don't see the point, plus added the weight of another servo etc.
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Old 04-28-2014, 10:50 AM   #23
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All those difficulties are easily overcome by placing brakes inboard (so no extra weight on the wheel) and using a floating central mechanism that pushes the pads equally left and right and pushes against a disc affixed to the diff outdrive (don't imagine you'd need to clamp the disc with a calliper, so a one-sided brake pad would be enough). This way it overcomes the left-right bias. This disc could slide over the outdrive and is attached to a flange part of the outdrive (like a belt pulley on a spool axle) with three little screws. True, there is still the problem of having one wheel with less load than the other but then, even if the unloaded wheel locks, it is not going to adversely affect trajectory because it's unloaded (i.e. its brake force is going to be lower than the fully loaded wheel even if locked).

Still, I think it would be less effective than the motor brake we have now.
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Old 04-28-2014, 11:12 AM   #24
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Problem with motor brakes is they too strong in mod lol. Very easy to rape a 64 p spur if you jam on them.
The force is multiplied by the gear ratio where direct wheel brakes would be more direct and linear in their effect.
In nitro its easy but with electric cars would need to mix a third channel in. Add a servo and all required equipment.
I'm not saying its not managable, it is but it definitely adds complexity to cars that already don't havr a lot of room.

But, I'd love to see it done. I mifht try something like that on a nitro car.
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Old 04-28-2014, 11:19 AM   #25
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You don't think that the braking from the motor lacks the feel and modulation of a mechanical brake? I think the braking from the motor feels more like an on/off switch than a real brake.
You don't get feedback in your trigger like you do a break pedal. What ESC are you running that it feels like a on/off switch? The ORCA's feel great to me.
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Old 04-28-2014, 11:23 AM   #26
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Tekin can feel a little on off like, or not as smooth as other escs .
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Old 04-28-2014, 12:49 PM   #27
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Scale electric touring cars do not drive the same lines as real life sports cars.

Adding realism to a scale hobby equates to lower performance. Real cars do not have locked front diffs, fixed gear ratios, and 1.5' of front toe out. I often notice engineers, electricians, and actual auto racers who are perplexed by the doctrine we use as RC racers. This is yet another example.
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Old 04-28-2014, 01:27 PM   #28
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Quote:
Originally Posted by (0000000000) View Post
Scale electric touring cars do not drive the same lines as real life sports cars.

Adding realism to a scale hobby equates to lower performance. Real cars do not have locked front diffs, fixed gear ratios, and 1.5' of front toe out. I often notice engineers, electricians, and actual auto racers who are perplexed by the doctrine we use as RC racers. This is yet another example.
Ding ding ding. .........and the guy with binary code name, hits I right on the nose. It's crazy how different real to scale is. Can you imagine what it would be like to drive a full size version of your TC? Trust me you would $hit bricks before you finish the first lap.......
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Old 04-28-2014, 01:50 PM   #29
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Can you imagine what it would be like to drive a full size version of your TC? Trust me you would $hit bricks before you finish the first lap.......
You'd also be dead.
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Old 04-28-2014, 02:37 PM   #30
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It has been done. Well, in the off road world. Date line on this is May 2013.

http://www.liverc.com/news/special_f..._(with_video)/

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