I am SHOCKED. Insane power

[tom255]

I am totaly agree with Aangel and Gixxer!
When i planned my setup i am surfed here on forum and everyone recommended 5S for 9XL motor and on paper yes it seems reasonable, but one factor i didn realized torque of this motor. We have tight track and for nitro buggy you never drive of full capability. I dont know how handle BL... I will think for start get new motor but first i have couple ideas what to do.
First Mechanical brake, to support ESC/Motor braking and second thing i will try to do clutch like someone here made. With clutch bell i hoppe i can more control truggy lunching that ideas what i thought on bed... :)
But lets try it first on my track :P

[joeling]

Hi AAngel,

Originally Posted by AAngel

Joe Ling, have you actually run a 9XL on 5S in an 1/8 scale vehicle? I know that it looks reasonable on paper, but in practice, it is just way too crazy for the track.

The problem is that when you gear down to attain a certain top speed, there is so much torque that you can't control the vehicle, no matter how careful you are with the throttle. Besides, the added weight of the 5S pack is no benefit on the race track.

I've tried it all. I have a good half a dozen Feigao motors laying around in assorted kv ratings. I've settled on the 9XL with the 4S lipo pack for the track.

At this point, if I had just listened to Glassdoctor, I could have saved myself a whole lot of time and money. Doing the math, my 9XL is only spinning at under 25,000 rpms; but that enough to smoke just about any nitro vehicle on the track, when geared 16/46. At 14/46, I'm just running with the fast nitro pack.

Sorry for a bit of thread hijack but yes I do run 5S using an 8XL with 100% EPA. I could have turned down the exponential a little but I can't be sure exactly. I run on a medium sized track with a decent straight. No problem in terms of control.

It took me 1.5 years & 5 fried esc of various makes & a few more feigao motors (7XLs, 8XL) & bloated Lipos to get to where I am now. Pretty happy with things now. I am running 13/46 gearing with theoretical top speed of less than 40mph. I live in the tropics so my biggest enemy is the heat & its effect on escs. I run 5S to keep the current down to avoid blowing up the esc. Highest registered current was 89A using the setup I have now. With 4S & 7XL, I was pulling more than 100A in short bursts & that led quickly to the demise of the esc then the battery.

Here is a video I took with my current setup :

http://www.rcgroups.com/forums/showthread.php?t=677442

I agree that the buggy is heavy with the extra weight but I just have to live with it. It weighs 4.1kg in its current form.

Regards,
Joe Ling

[tom255]

OK
I have tried my LSP on track, actualy track is 30% trigger track . Times is pretty good seems even better than my nitro times. The torque helps lots with jumps. Jumps right after coner where no time for speed up ur car it easyly do without any problems when others nitroman just go through jumps with low trottle i like it. But in other hand Torque not so good on longer stright, pretty difficult go stright without problems when you dont control your trigger. But after 10-15 mins of driving skills goes better and better.

And now sad thing about after ~30min of driving car stops i thought maybe it thermaled but i saw how smoke comes out. Immediatly i ran to my car and smoke goes bigger and bigger. Damn how scary, then i removed a shell i feel then disconnected my battery its heat melting all around. I have realy bad Experince with BK so now i will order Chinese plane ESC control it though PISTIX adapter and use Mechanical brake. Enough expenses. Its way too expensive burn ESC

[silentbob343]

whoa, that reached thermal alright.

[joeling]

Hi tom255,

I feel for u. If u are only on 30% trigger, may I suggest as others in this thread have mentioned to use a less hot motor like 12XL or 13XL or even milder to enable full trigger. I have also heard from others that braking stresses the esc. U can try to put a milder brake using a decreased endpoint (I use 65%) to help the esc more. Mechanical brake is an even better idea but add weight to the setup though. Having said that, with the power of BL, weight penalties can be somewhat ignored a little.

Just wondering - are u using a UBEC or the internal BEC ?

Please find attached a chart I downloaded from somewhere (maybe starluck) showing some spec like the KV of various feigao motors.

Regards,
Joe Ling

[Serum]

Holy Canoe..

That's one smoked controller for sure!! never seen anything like this.


What happened? spontanious?

[tom255]

Joeling- I am using UBEC
I will do first Mechanical brake becouse with plane ESC its only solution, and maybe bit later in future i will buy new motor. 30% Its for this track its realy tight other track bit bigger maybe i can go up to 50-60% who knows. But its goot feeling that you know u have so much power hided in your trigger. After some time I drove it pretty good. I only have 30-40 min brushless experince so i need time to learn my setup. Maybe you right buy 12XL motor and i am will be happy :)
To Serum
Yes its spontanous it worked 30min before and i checked ESC temp before its about 60* degrees and let it cool down then on first lap suddenly smokes comes out.
Yeah i saw first time too, how electronics can burn. SCARY