Dark Impact, lasted one run then SMOKE !

[J4CKO]

Hi, I am an older guy (36) just coming back to R/C Cars after 15/20 years, I claim its for my kids but hey, why not !

So, I bought a Dark Impact, radio gear, ESC and 2 3300 mah cells, also as I could never afford a powerful motor a 12 turn Reedy modified.

Put it all together, ran it with the 540, all was well, trimmed everything and it was runnign well but very slow with the 540, too heavy, too much grip so decided to spice it up by fitting the Reedy.

First run went well, very quick, checked everything and it was fine (apart from getting dog poo on it, but that's another story), nothing too hot, ESC was cool as anything, ran it for quite a while checked again, it started stuttering a bit but I put this down to a low battery not wanting to turn the mod motor, as opposed to just getting slower and slower like the 540.

Anyway, later my dad came round and wwanted to see it run, put in a frssh stick pack and the ESC (Mtroniks Viper RV11) went up in smoke !

Now, I know I havent been near an RC car (a Proper one) for a while, but am wondering waht I did wrong or is it just a duff ESC.

I was going to go 15 turn but the retailer didnt have anything other than a 20 and a 12 and did a good deal on the Reedy, I fancied having some real power !

So, now, lost all confidence, feeling dejected as I was enjoying myself with it
the kids are gutted as they didnt really get a go.

My theories,

1/ Stick pack shorting or something, it had been charged and all seemed well but handt been run, I dont think, they are identical and I cant remeber which I ran with the 540.

2/ Over ambitious motor choice. (it say it will do down to 11 turns), cant remember what the double/triple bit means, can someone enlighten me.

3/ Poor speed controller

4/ My error, but it was running before and I cant see how you can connect it wrong, if you get the motor wire wrong, it just goes backward ?

5/ Heavy handed use, got carried away once I had checked it, sliding it round on grass, gravel, tarmac !


I now kind of wish I went for Nitro instead as power in electric RC just seems so fraught.

And my hands still smell of burning electronics.

[Metla]

Did you gear the motor down to suit?

A 12t motor lacks torque, so you need to lower the gearing so the motor can spin up to top speed, Otherwise shes just under massive strain, and something will die.

A 12t running how it should run would be uncontrollable for someone who hasn't driven an RC in 15 years, I would say you would have shattered the car on your first run.

Suggest you get a 19T(Komodo Dragon) motor, especially if your going to let your kids run it.

[hijacker]

I'd have to disagree with Metla. If you want speed use your 12 turn. But that isn't really the point of your question. It does sound like you smoked your esc, if Mtroniks says the esc can handle an 11turn motor, then it shouldn't smoke from a 12 turn.

Here's my advice. First charge your batteries, and give them both a try. If you have STEERING but no THROTTLE, then it sounds as if you smoked the esc. If nothing works, then you have some other problem, the receiver perhaps.

If you think you killed the esc, take it back to the hobby shop you purchased the car at. There is probably a 30 day warranty.

Good luck.
Chad

[J4CKO]

I rang the retailer (modelsport.co.uk) and they sid to just send it back and they will check it out.

I can see the point about gearing but the DI seems fairly low geared anyway out of the box, it accelerated cleanly, didn't bog down and got to a decent (but not ballistic) top speed, at no point did it seem to be labouring, it would take off and spin all four wheels !

Didnt realise about the torque thing, I am going on my learnings from when I was a kid, less turns = faster, most we had then was a 15 turn motor on a cheap ESC, it was run (in an Optima mid Custom) hard, day in day out for years with no issues. So are you saying that for bashing around the garden and up and down the street a motor with more turns may be a more enjoyable drive, less outright power but more low down punch ?

As for uncontrollable, I am not a driving legend but I play racing games, I drive quick cars, have done R/C a lot before so am reasonably adept at controlling a 4 wheeled projectile, the lairier the better, wheres the fun in controlling a capable 4wd chassis like the DI with a motor that doesnt have enough power to overcome the grip, oversteer, understeer, bring it on !

Also I did think that the reverse on the ESC wasnt very snappy like I remember on the old Optima mid, any idea why this is ?

[J4CKO]

Also, I went back to electric as its what I remember, plus its clean and quiet, would I be better getting a Nitro truck for bashing round the garden taking out life's frustrations ?

[TunaCan Charlie]

I've gotten ESC's wet before and that's exactly how they acted. Stuttering before finally stopping and smoking and.................paperweight.

Are the heatsinks filled with dog waste? Hahahahaha!!

Good luck and welcome to the forum! :D

[Jayboy]

Ive got the exact same ESC, and it does come with a 12/24 month warranty. I think the 12turn motor may be a bit too much for the esc to handle by the sounds of what happened.
I run a 13x3 motor on my esc, and it does run quite hot, but i have no idea what happened to yours, because in theory the 12 turn motor should just about be ok.

Maybe you didnt leave the esc to cool down for long enough between putting your 2 battery packs in....?????

[J4CKO]

Hmm, it didnt get we, for once its pretty dry here in England !

It was four hours or therabouts between runs, shouldnt I be theoretically able to cane it all day battery after battery ?

Going to pack the ESC up and send it them back tonight, must say its still annoying when you are old and compartively (compared to when I was a kid) wealthy, stuff like this used to be the end of the world !

[Jayboy]

i dunno what happened, must just be a faulty esc???
...and yes, the weather here in England isnt that bad at the moment is it?!

[Jack858]

no its not, sorry for jacking that....
How many of you guys are in england coz I have never seen any1 here with anthing more r/c than one of those nikko things lol.
J4CKO, most esc have a delay before engaging revese do you dont destroy your drivechain!
I think a nitro would be a better option, but its all down to preference,

Jack

[J4CKO]

Ha, we have a Nikko one, a Subaru, was ok for a while but its lack of power was frustrating.

[Metla]

Regarding gearing, My 19T labours a little too much for my liking in my DI, so I'm changing the gearing and fitting a slipper. Top speed travel is a little too fast to be controllable down the back straight of my local track, though thats due to the track having a rough patch and a kink in its fastest spot. She goes like a bullet. No chance in hell of getting it up to top speed in my backyard even though its quite big.

Reverse, Again, gearing, lack of torque and that fact these motors are built to go very fast in one direction, forward. Though it may have been your ESC, I have a couple of crapped out ones that will only let the car crawl when going backwards.

[J4CKO]

So, perhaps I get the ESC replaced , Ebay the 12 turn and buy a 19 turn or therabouts ?

[Metla]

Definitely get the ESC replaced, Then I suggest asking in the main Dark Impact thread about running a 12T motor on stock gearing. More input can't hurt.

I cant imagine that your 12T is operating at anywhere near its full capabilities with stock gearing.

[J4CKO]

My requirements are just to have a car that works, is easy to operate for the kids and quicker than stock.

ESC is all packaged up and ready to go to the post office.

Thanks for all the input, will update when I hear back from them.

[Stuart B]

i Run an 11x2 in mine. I had to drop the gearing. I used the 85 spur that is in the kit (says not to use it) and bought the 23 and 25 pinion set. Running the 23 at the moment. There isn't enough adjustment on motor position to use the 85 with the stock 26 pinion. I run a Quake no limit esc, it gets warm to the touch, but not hot.

The batteries get a bit warm though...possibly too warm. The motor doesn't seem excessively hot.

It doesn't sound to me that is is fully wound up either. Even after 30-40 metres its still winding up a bit on tarmac.

Might go brushless at some point though when the comm/brushes are nacked.

Stu

[cybcow]

I wouldn't go nitro as electric will be easier for the kids to use. Electric is cheaper to run because you don't need to buy a new battery as quickly as you need a new jug of fuel. If you want it to last you need to lubricate your engine and carb after every time you play with it. As well you can't idle a nitro vehicle for long periods of time. Plus electric you can do inside and outside racing.

I have done both with several electrics and two nitros. Personally electric is a better choice if you ask me. Nitro has its fun but I'm not sure its really worth the price or the hassle.

[Stuart B]

I wouldn't go nitro as electric will be easier for the kids to use. Electric is cheaper to run because you don't need to buy a new battery as quickly as you need a new jug of fuel. If you want it to last you need to lubricate your engine and carb after every time you play with it. As well you can't idle a nitro vehicle for long periods of time. Plus electric you can do inside and outside racing.

I have done both with several electrics and two nitros. Personally electric is a better choice if you ask me. Nitro has its fun but I'm not sure its really worth the price or the hastle.

I have had a couple of Nitro cars, but th DI is more fun than either one I had...even if it has less top speed. I can't be bothered with all the faffing and muck.

I could get them running sweet, but they seemed to need tweaking for weather and so on. Its bit like older cars having carbs only ever running perfectly for one specific set of conditions, fuel injection and electroninc ignition sorts it out so its spot on every time. I guess a nice brushless setup is more like modern car injection/ignition.

[SS Pede]

I just want to second or third the suggestion of lowering your gearing. Some motors still seem "pretty fast" when they're over-geared, but that doesn't mean they aren't getting stressed out. A 12 turn motor is WAY faster than the stock Tamiya motor and needs to be geared quite differently. I don't own a Dark Impact so I won't try to suggest a specific gearing, but suffice it to say a 12T motor is not designed to be run at the same gearing as a 27T turn. :)

[Itsuru]

With MTroniks ESC's they usually can't handle what they say they can, it's always safe to go to a higher motor. e.g. a 15T ESC works better with a 17T Motor than a 15T motor.
It's the price you pay for the affordibility of MTroniks.

Sounds to me like it could have been a combination of gearing, ESC and motor choice.

[J4CKO]

Itsuru, I think you are spoton there, just waiting to hear back about it from the shop, will give them a ring tomorrow if I have not heard, its annoying as it snowed here last night !

[J4CKO]

Ok, Mtroniks/Modelsport are sending a a new ESC.

So, I have ordered some new pinion gears in sizes 18,19,23 and 24 T sizes.

The kit comes with a 26T pinion and two spurs of 78 and 85 teeth.

I was using the 26T pinion with the 85T spur, so it was actually sightly lower geared than stock (stock being 26T pinion and 78 spur).

So, out of my selection of cogs, what should I use to avoid smoke this time, is there anything else I can do.

The guy in the model shop conceded it was probably bad luck but also mention tight transmissions can cause probems, mine seems fine but I did tighten the rear diff a bi as it was slipping.

[Stuart B]

Ok, Mtroniks/Modelsport are sending a a new ESC.

So, I have ordered some new pinion gears in sizes 18,19,23 and 24 T sizes.

The kit comes with a 26T pinion and two spurs of 78 and 85 teeth.

I was using the 26T pinion with the 85T spur, so it was actually sightly lower geared than stock (stock being 26T pinion and 78 spur).

So, out of my selection of cogs, what should I use to avoid smoke this time, is there anything else I can do.

The guy in the model shop conceded it was probably bad luck but also mention tight transmissions can cause probems, mine seems fine but I did tighten the rear diff a bi as it was slipping.

On mine withe 85 and 26 ythe meshing was too tight....yours might have that critical extra bit of clearance, but its worth checking that you have a bit of play. I have seen gear tables for the DI somewhere, and the 26/85 weren't allowable on it. If it is meshed too tight, that may have contributed to the smoking due to the extra drag. The 25 tooth is allowable with the 85.

Where did you get the 18 and 19, the smallest I have seen is 23 (which I am running. Did you order the 0.5mm gears the DI uses?

Stu

[J4CKO]

Yes, I ordered the 23/24 off Ebay and the others off http://www.anticsonline.co.uk, they are all for the DF03.

[Stuart B]

cool. what are the part numbers for the 18 and 19? Might grab those my self.

Stu

[Metla]

I have some of those smaller 0.5 pinions, Turns out they are for the Astute,
And they are two small to reach the spur, So some modification will be required.

I'll have a look and see if I still have the packaging, I also have a list of all the possible spur and pinion options and the final drive ratio they give, But they are on my other PC, will post those later.

Plus some guy created a website dedicated to the DI which contains a lot of the same info, Though that too is bookmarked on my other PC.

[Metla]

Right, No sign of the packaging, Though I foun the text file with the ratio's.

Spur 78T: 26t (9.17), 27t (8.83), 29t (8.22)

Spur 82T: 23t (10.89), 25t (10.02), 26t (9.64), 27t (9.28)

Spur 85T: 23t (11.29), 25t (10.39)

and the Dark Impact site

http://web.aanet.com.au/fir/dark/index.htm

Look under Setups and downloads for a gear ratio chart.

[Demon-TC3]

OK so, i used these Mtroniks things for a while and at the end odf the day you do get what you pay for...that said they are actually pretty good ESC's spec wise for the price.
Now i have heard this allot where people do burn their esc's using motor that should be fine and all i ca say is that Mtroniks are a little over comfident of their esc's

For the RC11 i would not use anything lower than a 13 turn, also see if you can land yourself a power capacitor and isntall it, will help the esc run a little cooler.

If you are getting a free replacement, ask them for an upgrade and get the Mtroniks RVMAX. it has no motor limit so you should be ok for motos of 12 turn, i have used mine for about 2 years and really did like the speedo.
As for driving in the UK, there are clubs arround you just gota find them, i got 3 or 4 clubs within an hours drive....:D

[relayer]

Just check those gears you bought before using them. I had a look on that shop website and they looked like 0.6 module pinions, which wont fit.

Contrary to what was mentioned earlier, the Tamiya Avante used 0.6 module pinions, hence Tamiya introducing the "AV" range of pinions.

You have to make sure you're using the 0.5 module pinions, the only other Tamiya car that cam equipped standard with this pitch was the SUper Astute (as far as I'm aware).

I'd say that you were overgeared, as with todays high-voltage cells, motor seem to need to be undergeared more than a few years ago.

For a 12turn I'd start with a ratio of 11:1 and see how it goes from there - it's always better to start undergeared!

Another thing you can look at is the motor brushes. Take them out and inspect the back of them where the brush wire goes in. If this area is discoloured (compared to the rest of the brush) then this indicates the motor is getting too hot - usually from overgearing.

There are good forums on the Dark Impact at

www.tamiyaclub.com and
www.rctech.net

[Metla]

Just check those gears you bought before using them. I had a look on that shop website and they looked like 0.6 module pinions, which wont fit.

Contrary to what was mentioned earlier, the Tamiya Avante used 0.6 module pinions, hence Tamiya introducing the "AV" range of pinions.

You have to make sure you're using the 0.5 module pinions, the only other Tamiya car that cam equipped standard with this pitch was the SUper Astute (as far as I'm aware).



Cheers for that, I'll go back and change the mention of Avante to Astute.

[J4CKO]

Looks like the 18 and 19t one might be wrong, they werent expensive so not bothered, was going to try the 23t with the 78 pinion giving 10.36, would this be an appripriate ration as its about the lowest I can go at the moment, or am I best off going for a less powerful motor or even just using the stock one ?

[J4CKO]

Well, the new ESC arrived (Same one again), fitted it and the 23 pinion, 85 spur.

Ran really well, had it going for 20 minutes, gentle at first, had to tighten the diff up as it was slipping and then built the speed up, was being careful as there was no daylight and I didn't want a 'Dark Impact' (Sorry, couldnt resist !), at the end I was confident that all was ok.

It was pretty fast, too fast for our road in the dark.

The ESC did get hot, too hot to hold your hand on after, so is this ok, its pretty enclosed in the DI shell with no ventilation, I was thinking of putting some drilled holes in the shell above it, any suggestions ?

[Jayboy]

in the shell in my baja champ, i have cut out the windscreen and side windows, and fitted thin metal mesh to allow air to circulate through the body, but also keep stones and other small random objects out.
It keeps my mtroniks RV11 pretty cool (with a 13x3 motor!)

[J4CKO]

Just a quick one, what does the double/triple bit actually refer to and what is faster/more power hungry.

[tcolesen]

It is my understanding that the triple will give higher RPM compared to single, where single is more torque but less RPM. Double is a middle ground, but triple would be the most power "hungry" and fastest.

[Jayboy]

yeah, it certainly is fast, but does drain a lot of power from my measly 2400mAh NiCad battery!

[J4CKO]

I am on 3300 cells and it seems to last pretty well, well usually longer than the ESC !

[Quinton]

Also, I went back to electric as its what I remember, plus its clean and quiet, would I be better getting a Nitro truck for bashing round the garden taking out life's frustrations ?

Heck YES! Savage!

[awnelson]

I would have to say that from using MTroniks that they are a crapshoot. I bought two identical ones, one powered up and ran fine; the other shorts out under full load, loses the BEC circuit and reboots itself. Called the U.S. distributor and haven't heard back from them for 1 month now. Had LRP, Duratrax, Novak, HPI, Futaba, Traxxas and Orion speed controls as well and this is the only one that loses power under heavy accelleration.