Testing the waters with BL
 

Well, I've done the go fast type BL, but for the first time I'm experimenting with what I guess you could call "go slow" BL.......in a crawler of course. I picked up a KMS 2814/08 outrunner from Hobby People earlier in the week, and finally got to drive it today.

I chose this motor because of the 540 bolt pattern, but the only problem with fitting it was the 4mm shaft, we got around that with some supplies at the store. A friend figured out that 5/32" brass tubing is essentially 3.96mm, close enough to fit the bearings snugly. To use "normal" pinions, I slid some 1/8" stainless steel rod inside the tubing, and later added JB Weld to keep them together as one piece. To hold the shaft in, I made a flat spot for the endbell's set screw, and just used the pinion to hold the other side in (it doesn't bind at all).

After driving it on 3s A123(paired with a Mamba Max esc I had laying around), I'm hooked. Wheel speed is about the same as it was, but low throttle is silky smooth, with tons of torque too. I really like it, but will be sure to beat it up a little just to see how it'll hold up before I fully stand behind it.

You should check out the Crawlmaster motor at holmeshobbies.com. I was running this in my Super and managed to snap a revo driveshaft with this motor. TONS of torque.

Crawlers are cool and very challenging. Who would have thought going slow required so much concentration. You should post a pick of your crawler.

Most recent pics are from today's outing: http://www.rccrawler.com/forum/showthread.php?t=89083 . Mine's the one with the flames, it did okay. I need to widen it, and need to tweak my suspension for easier twisting.

Oh, and I'm not sure if this can be answered here, but my MM esc tends to kinda "lock out" when the truck is going uphill and starts to roll backwards. I've got 50% drag brake set, and that works amazing when facing downhill, but it has a very hard time getting going uphill again if I don't stay on the throttle. Could this be gearing, or a setup with the MM controller somehow? I have it set for low timing hoping it'd be a bit smoother, maybe that did it?

No pressure to reply though, I'm gonna post the same question on RCC where I'm sure there's more experience with outrunners and crawling. Still, any help appreciated. :)

Could be related to the "Neu/MM syndrome". All the outrunners I know of use slotted stators, which is what the MM has a hard time with. Don't know if this is the case, or if this even matters with outrunners, but try increasing the start power and increasing punch control in the MM software.

Okay, I'll take any help with it right now, so far I'm only half-pleased with it. Amazing torque, and stupid runtime with my A123 pack today (2.5 hrs, still had lots more), but the rolling backwards was a little annoying.

Well, make your adjustments individually in small steps to find the "just right" setting. Once you get it right (assuming you'll be able to), please post back here with what settings worked.

yes - please do post back with the settings you end up happy with! i'm building my Stealth up now - the MM is in the mail, and i'll be using 55t brushed motors. i know it's no where near the same, but i have no clue what good settings would be for crawling.

Well, here's what I got from JohnRobHolmes on RC Crawler: "Gear down. You are geared way too high. Put a 13 or 15 on there. Then turn your startup power to high, it wont affect your startup speed. What is your drag brake set to?"

Another guy suggested to put timing to medium, I'll go ahead and do everything suggested so far and see what happens. I might be going out for another run tomorrow at the ultimate crawling grounds Vasquez Rocks, but I have areas around my house that I can still test it out.

I'll be sure to let you guys know how this turns out, I'm anxious for this setup to live up to its full potential too!

My crawler does something very similar, where it doesn't like going forward while rolling backwards. It's got that Mamba 25 you sold me, along with a KMS 2826/06 (you shoulda' gotten this one!), and 3s Lipo. To get it to go forward, I've found I have to hit reverse, where it seems the purpose of doing so is to get the Mamba 25 to locate the position of the rotor.

Well, more info from the crawler guys:

raptorman57 - "IMHO,you're running the best ESC for crawling. Like John says to everyone.....Gear down,volt up. Thats how you make the outrunners work smoooooooth. Once you gear down,you'll see the problems go away. If your wheelspeed isn't where you want it,volt up to get it back.

I set all my Mamba's at 100% drag brake.

My start up power is on high.

You can also adjust the throttle and brake curve to fine tune it more to your likings."

JohnRobHolmes - "If you like to let off of the throttle and let it sit on inclines, put more drag brake in. They can get stuck into a downhill rolling mode if the geardown and voltage is too much to overcome."

Those were the most helpful ones, a couple people chimed in with the esc that I "should have got instead"......which doesn't do me any good anyway. I only used this MM esc because I wasn't using it in anything else and knew it'd be up to the abuse.

Travis, why? This one seems to have stupid torque even over geared, but is small enough that it's not hitting the Stealth tranny. Besides, doesn't that one have a 5mm shaft? It wasn't too hard to make the 4mm to 1/8" conversion, but 5mm to 1/8" would be a bit harder.....and I still think it's too big.

dude, i just now looked at those shots. those are great! looks like someone has a nice DSLR paired with a circular polarizer. :yes:

do you have, or have you tried, 4s a123's? esp. concerning the 'volt up to eliminate the problem' comment. i'm curious, as i plan to run 4s2p a123s in mine. i was worried it might be too much, but i also planned to gear down a lot.

4s A123s should work just fine. The MM works fine with 4s lipos, which has higher voltage.

You think the torque of your motor is stupid :rofl:.

I have access to a machine shop at UCI (University of California, Irvine), where I go to school. Outrunners feature removable shafts, so I simply took the shaft out of the motor, and turned it from 5mm to 1/8". When it still had the 5mm shaft, I was running mod1 gears. Now with the 1/8" shaft, I occasionally have a problem with stripping 32p gears, and would strip out 48p spurs all the time.

right on - i'm not worried about the MM specs, as i ran 5s through it without problems...but that was in my heavy maxx. i've never crawled at that high of voltage though. could be fun!!! :party:

Has anyone tried a quark yet? The mambas just dont work that good. A 4s pack is just way overkill for these little trucks, you will just break things. I am going to get a quark and see if it is any better

I have used quarks in crawlers a good bit. The low speed control is a bit better on low voltage, but they have an annoying habit of going in reverse when the tire is bound. I use them mostly in scale rigs that don't see hard crawling or comp use.

Have you gotten everything smoothed out dabid?

great avatar, mr. holmes. :lol: :oh:

does the MM have the same annoying habit as the quark? i'll find out soon enough as i just got the 'new' updated MM today in the mail. i have a variety of a123 packs to see what works best - 2s2p, 3s2p, 4s2p...and that's as high as i want to take it, although i can also go 5s, 6s and 7s.

i'm also eagerly awaiting my custom CC BEC that i ordered from you. :yipi:

Although the mamba 25 has reversed on me a few times, I have never had a mamba max go into reverse when I told it to go forwards.

What is new about the mamba max you are getting? New firmware?

this is the info i got a while ago from BPP:

We were originally informed by Castle Creations that shipments of the MambaMax Combos and Controllers would be taking place this week to Vendors. Unfortunately Castle Creations is still behind in their production of the MambaMax controllers and they have informed us that they will not meet the production goal of shipping this week, delaying all shipments to all vendors & customers. The reason for this delay was with the new production of the actual circuit board itself for the MambaMax controller (Castle Creations builds all the controllers in-house at their own production facilities in Kansas) . We have learned that this new production of the MambaMax has several updates incorporated into it along with the latest software rev. loaded so while the wait for the latest version of these controllers is painful, it will be worthwhile to have the most up to date version.

I have a brand new one in hand, firmware is 1.09 like all the rest.

i just checked my 'new' one, and it's the same too. castle link software (loaded from the cd) is 3.0, and firmware options are 1.09 and 1.07.

castle doesn't have anything on their website about anything new with the MM either. maybe joe will pipe in on the castle support portion here.

It sounds to me like they just rearranged some components on the circuit board. In that quote from BPP it says nothing about firmware or software alterations...

Sorry it took me a while to get back to everyone, I haven't been able to test the truck either. Last Saturday during the big outing, I rolled the truck and it slid upside down for a ways ripping off the antenna wire at about 2" or so. It worked good enough out there in the hills, but glitched like crazy back home. I finally swapped it out, but another of my A123's has bit the dust, so I'll rebuild the remaining loose cells into a single 4s pack......should have stump pulling torque then, just have to work out the mounting.

Well, I tweaked the ESC the way I was told and bumped voltage to 4s, and it worked great! I ran the entire pack down on Saturday without issue, no jerky starts or rolling backwards out of control, no heat issues either. However, I decided to move some rocks around in our backyard for a better course and somehow sent the ESC into a coma. Even with CC's help over the phone, there was nothing to do but send it in. I'm not sure what went wrong, but if worst comes to worst, I'll have to pay $50 to get a new one.

I'm not sure if I nuked the motor too, it seemed quite hot and let off a whisp of smoke, I s'pose I could hook up a Mamba 25 I'm not using and try it out.

Were you running the mamba's internal BEC?

i'm curious if you ran the internal MM BEC as well.

i'm planning to put my Stealth through it's maiden voyage tomorrow and was planning to run 4s a123's through the MM internal BEC. if that's what blew yours, i'll use my CC BEC. (maybe i'll just run my CC BEC anyhow...)

I was using the CC Bec, set to only 6.2v too.........no idea what went wrong, but it's in Castle's hands now.

Crap, rigged up my Mamba 25 this afternoon and it did the same non-arming thing, it was the motor that kept it from going through. I took the old nuked one back to the store and returned it for a brand new one but still the same KMS 2814/08, I think I'll just run 3s for now with the Mamba 25 until I get the Mamba Max back......hopefully they'll tell me it's still fine too.