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Mechanical Brakes on brushless buggy

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Old 03-04-2008, 04:02 PM
  #26  
Shark413
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Default RE: Mechanical Brakes on brushless buggy

Got the channel 3 brake mixing setup and it works perfectly. With the ESC set to zero brake, when you press brake on the radio the servo applies the brakes, when you go to neutral or power on throttle the brake servo stays in neutral. This is exactly what I was looking for, adjustable brake bias and the added benefit of removing a huge load (motor braking) from my ESC/Battery. I ordered longer linkage but it was the wrong size. I reordered and as soon as it arrives I will hook it up and start finetuning. I have just been spending the time drill/milling parts to lighten it up, lost several ounces from the battery tray and motor mount.
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Old 03-04-2008, 04:19 PM
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Default RE: Mechanical Brakes on brushless buggy

FoamyVictim, in my opinion because my conversion is heavier than nitro buggies of the same make (I own a nitro Kyosho 777 SP2 as well) I need the extra power to compensate for the extra bulk. The nitro buggies will handle better and react faster because they have less bulk. So a Feigao on 4s gives me greater power and speed over a .21 nitro buggy. This pretty much allows me to run even with most nitro buggies I run with at the local track. If I had the same or less power I think the nitro buggies would have an advantage. 4s lipo provides much more power than 3s using a feigao 8XL motor, and this is a high draw motor. Having too much motor for a battery can also cause heating problems (motor tries to draw too many amps). I am running 3s lipos in my Jammin CRT.5 conversion using a CS-M5700 (Mamba Max) motor and it is super fast, much faster than any nitro CRT.5 and close to the speed of 1/8 buggies, but then it is much lighter than my buggy (almost half the weight).

Here are some speed comparisons I made at our local track, using a bushnell radar gun and the main straight which is about 75 feet, remember these cars are geared for the track and not maximum all out speed.

Nitro Kyosho 777 SP2 OS V-Spec .21 = 27mph
Brushless Kyosho Kanai III Feiago 8XL on 4s2p lipo = 30mph
Brushless Jammin CRT.5 CS-5700 on 3s2p lipo = 28mph
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Old 03-04-2008, 05:48 PM
  #28  
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Default RE: Mechanical Brakes on brushless buggy

Cool, those are the answers I was looking for. I'd like to build my own one day, so all this groundwork you're doing is very helpful... thank you!
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Old 03-04-2008, 06:31 PM
  #29  
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Default RE: Mechanical Brakes on brushless buggy

In looking at the above comments, I like very much that you called out the issue of motor load for braking being a electrical stress on the ESC. I've thought that was an issue too, which leads us to needing the stronger ESC to handle it (as well as powering a motor choice).....

At the very least it seems, the less stress on the ESC will yield longer duty life and less chance of random failure during a race.

For our Phase I test platform, we went with a Feigao 7XL (I can't remember the spins/volt difference to the 8XL) as its an inexpensive get going type step, with our on track winter season drawing to a close (we wanted to run a few times before time ran out).

Because we had on hand a pair of 7.4 (2 cell) / 4000 Lipo's, thats what we're using at the moment. For 5 minute races, we've not needed more than about 1500 mAh to top off after the race, and had no heat issues with either the motor / ESC or battereis (running a CC Mamba Max).

Most folks we are running with are using 4 cell LIPOS in the 5000 and 6000 range (I think, and there may be exceptions) - with the motor of choice being an NEU.

As the Feigao is 2 pole, and the NEU 4 pole - the NEU is supposed to be more efficent giving cooler running and longer run times (and more power).

(Word has it the new CC Monster Max package will have an NEU influenced motor)

Have you given any consideration to the better motors? We anticipate an upgrade if we begin racing this summer with any regular basis.

In the mean time we're still working out our chassis set up and various equipment mounting robustness and layout.

I didn't notice in the pics above, are you running a BEC for servos and receiver? We're running cooling fans off straight battery voltage, power rather than lower BEC voltage.

(From what I read, not using the ESC's onboard BEC is supposed to also be easier on the ESC in these high power situations)

Thanks.
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Old 03-05-2008, 01:52 AM
  #30  
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Default RE: Mechanical Brakes on brushless buggy

HandyRacing, yes I went with Feigao because they are decent motors for the price. A good way to get started, plus at the time I had a brushless buggy, truggy and monster truck so buying a motor like the Neu (x 3) would have been very pricey. Some day (hopefully soon) I will replace the Feigao with a Neu 1512 in my buggy, and if/when they come out with the MMM/Neu combo, that would go in my Truggy.

I strongly believe the more stress you can take off the ESC/motor the bettter, so yes using mechanical brakes will have the added benefit of reducing electrical/mechanical load when braking. This is especially true if you have to brake coming off a jump, the stress is far higher and can damage drivetrain parts and overstress the electrical system. I have broken two feigao rotors (magnets separated) and I believe this was partially due to extra stress from braking. I have since repaired the motors (rebonded) and will run them with the mechanical brake setup to see how they hold up.

Yes I am using a remote CC BEC with the MM ESC BEC deactivated. Using the ESC BEC with 4s2p lipo will cause the ESC to overheat quickly and cause possible damage to the ESC.

I am running the cooling fan off the BEC output because I am using a 5 volt fan and running them off the battery would burn them out. The 5 volt fan keeps the ESC cool and does not draw very much power from the battery. I normally run a mesh screen over the fan, because any pebbles/rocks that get thrown in there will damage the fan and/or cause a short which will drain your battery. I also have an aftermarket heatsink on my MM which is about twice the size of the stock heatsink.

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Old 03-05-2008, 11:44 AM
  #31  
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Default RE: Mechanical Brakes on brushless buggy

Yes, we put a lot of thought into the heat sink / fan choice(s) on the ESC too.

I even picked up a Peltier Chip (solid state refrigerator) to play around with for experimentations....

and then the fan. That's why we went with the 12 volt (Radio Shack) computer fan, to take the load off the ESC BEC (we pulled the red wire to disable it). In our case, with our design setup "geared" toward a 5 minute race and planning on a large capacity LIPO, rather than worrying about longer yard bashing type driving, we figured the minimal amp draw would be no bother in the bigger scheme of things.

One of the things that came to mind is any G-forces from hard landings on the track will transmit any kinetic load of the heatsnk / fan directly to the electronics board of the ESC if they are physically coupled together as in OEM.

Even a clean jump landing has the belly smack effect, not to mention straightaway long cartwheels that these big fast beasts need to endure.....

With this in mind we de-coupled the weight of the fan and mounted it adjacent to, and blowing across the (stock) MM heat sink. In my mind this serves to reduce the weight bourne by the circuit board.

We've also ruined a fan or two during track testing, I was thinking from hard hits - but I think the screen to protect the fan blades from small objects is just plain brilliant.

This sharing of ideas is so valuable in moving our mutual projects forward, and the new genre of Converted Brushless 1/8 scale RC racing forward - this community forum is such a powerful tool.

Thanks for the sharing of little details....
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Old 03-05-2008, 01:00 PM
  #32  
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Default RE: Mechanical Brakes on brushless buggy

HandyRacing, you are absolutely right about kinetic energy acting on various parts of the buggy. Especially the ESC, which consists of a relatively light circuit board with a heavier aluminum heatsink glued on top, sitting in a plastic case. I have lost the ESC from it's mount (double side foam tape the full length of the ESC), I had the circuit board come loose from the case and I even had the stock heatsink pop off from hard impacts. My current ESC has been modified to reduce these issues and I have not had any of these issues since (been about 2 months). The heatsink was applied using thermal epoxy and some JB weld around the edges, the circuit board has a small bead of silcone sealer around the edges and the MM case is actually bolted (from the inside) to the mounting plate. I am going to remount the ESC using some industrial grade velcro I found, it will act as a cushion and make it eaiser to remove for repairs. I just hope it holds and doesn't shift around too much.

Also kinetic energy caused the individual cells in my lipo battery to shift (slide) slightly because they were not bonded together, they were just shrink wrapped on the outside. Eventually the shifting of the cells could have torn one of the tabs off. I removed the stock shrink wrap and used thin double side grip tape to bond the individual cells together. I then reshrink wrapped the battery, no problems since. Some batteries come bonded from the factory some do not.

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Old 03-05-2008, 01:23 PM
  #33  
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Default RE: Mechanical Brakes on brushless buggy

We use the following for holding in place the ESC, receiver, some even use velcro (we would use this stuff) to hold down the batteries, as under race conditions every little bit helps to finish. The key being to properly prep the adhesive surfaces to get rid of finger print and other oils, grease, and other grime.

Its available in our local big box grocery for a few bucks for several strips, which is enough quantity to last for quite a few installs in a number of rigs.

http://www.andybaird.com/travels/gertie/superlock.htm

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Old 03-05-2008, 07:00 PM
  #34  
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Default RE: Mechanical Brakes on brushless buggy

HandyRacing, that 3M stuff looks great. I will definetly try and get my hands on some and try it out. Like I said it will be used so I can change out my ESC if it becomes damaged or inoperable (I have spare ESC's and motors). Right now since I have it bolted to the mounting plate it is major surgery to get the ESC off. Thanks.

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Old 03-10-2008, 09:06 PM
  #35  
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Default RE: Mechanical Brakes on brushless buggy

I got the buggy out to the local track and ran several packs thru the buggy. The mechanical brakes worked perfectly, strong but with great modulation (feel). It made the brushless buggy handle so much better, my poor Kyosho 777 SP2 nitro buggy hardly got any track time. Having run this buggy with motor brake only, for a long time, all I can say is I would never run a 1/8 scale brushless buggy on motor brake again. The difference is unbelievable.



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Old 03-10-2008, 10:06 PM
  #36  
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Default RE: Mechanical Brakes on brushless buggy

Shark you Freakin RULE! Glad to hear it worked out. I have allot more confidence in what I think a brushless racing setup can do.
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Old 03-11-2008, 03:22 AM
  #37  
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Default RE: Mechanical Brakes on brushless buggy

FoamyVictim, thanks for the pops. Yeah I can't understand why some big name company doesn't market a brushless buggy. Probably the expense cuts too much into there profit margin. You know what, now that I think about it that's fine, I have yet to see another brushless buggy at the local track and it's cool to have something different. I am probably faster using my nitro buggy (mostly because it is lighter and is newer model) but I can tell you that the fun factor is off the scale with my brushless buggy. There is this one section at the track, a big table top followed by a big double jump that no one can clear, you have to jump the table top, landed in front of the double and then jump that. But with my brushless buggy I can clear the entire section, which gets a great reaction from the other racers/spectators. It's not the fastest line but it sure is fun.
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Old 03-30-2015, 07:16 PM
  #38  
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i just got a losi 8 truggy with tekno conversion.the guy i got it from got it from a trade and the original owner uses mechanical brakes.idk how to set it up.do i just install servo and put the linkage like how we do it on nitro?i read on previuos post to set esc brakes to 0?pls help thanks..
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