Brushless TNX

Combatcm · #1 07-27-2006, 01:31 AM

Given the 2 speed, the transmission one way and the mechanical brake, do you think a feigao 9s motor could push the truck?

I'm not looking for a speed demon, I just want to know if the smallish motor with the 2 speed would work reliably.

This is using 8 cells.

It handled my MT2 almost as good as the .18ss engine and that's pretty damn good.

Mr. Constructor · #2 07-27-2006, 03:44 AM

These trucks need torque, over RPM, that´s why a small rotor like the one in a 9S will not push it that fast (like you wanted a speed demon) The major failure might be that the Motor has only got a 3,17mm (1/8") Shaft, wich tends to break easily when used under heavy Monster Truck conditions.

For a 2 speed and power application a L or even an XL should be used.
the RPM should be around 2200 RPM/min./V under 12 cell applications, under 18 cells it should be around 1700 RPM/min./V and the Motor should have a 5mm Shaft, wich is much more reliable for these heavy Cars !

Hopefully this helped you a bit !!

greetings from hamburg !

Combatcm · #3 07-27-2006, 10:52 AM

Oh, the motor is a 9s 5mm shaft. It's around 4000kv. When I put the revo spur on it it made the ratio higher. Stock is 43/17 and now it's 38/13, but I have 9, 10, 13, and 15 tooth pinions, so I can get a big range.

For the gear ratios I found that it will top out at 26-28 in first (if it could stay in 1st) and second gear should be around 36-38. So it sounds right where I would want it to be.

I'm going to try it anyway.

Micke_b · #4 07-27-2006, 12:49 PM

just a question what motor mount are you using?

Combatcm · #5 07-27-2006, 02:57 PM

http://www2.towerhobbies.com/cgi-bin...?&I=LXDBT7&P=7

26 is steep, but I had it. I put somespacers to raise it up. There is 2 screw holes on either end of the mount. It looks good, but I don't know if the screws can handle it, so I might brace it somehow. Maybe put something under the motor so any harsh landing won't snap the screws that mount it to the chassis.

spiff84 · #6 07-27-2006, 06:24 PM

my effort on a brushless TNX so far:
http://www.tamiyaclub.com/showroom_m...49197&sid=5594
Not run it yet though...

pcnutz · #7 07-27-2006, 07:19 PM

I did a brushless maxx with revo trans, with 12s I would not try a 9s

mdewitt71 · #8 07-27-2006, 08:22 PM

Quote:

Originally Posted by spiff84

my effort on a brushless TNX so far:
http://www.tamiyaclub.com/showroom_m...49197&sid=5594
Not run it yet though...

No offense, but it's almost more Maxx than TNX....have you ran it yet?

starluckrc · #9 07-27-2006, 11:23 PM

Quote:

Originally Posted by spiff84

my effort on a brushless TNX so far:
http://www.tamiyaclub.com/showroom_m...49197&sid=5594
Not run it yet though...

Looks like a good start. One note.......the Mtroniks BEC works quite well with 12 cells and may actually perform worse with an rx pack according to user reports.

spiff84 · #10 07-28-2006, 02:54 PM

hi
thanks for the tip, maybe i'll loss the rx pack, that'll save some weight. looking at ways to attach the batteries at the moment.
I've now updated the pictures with ones from my new camera.

Combatcm · #11 07-28-2006, 11:52 PM

Quote:

Originally Posted by spiff84

hi
thanks for the tip, maybe i'll loss the rx pack, that'll save some weight. looking at ways to attach the batteries at the moment.
I've now updated the pictures with ones from my new camera.

Are you aware of battery cups?

http://www2.towerhobbies.com/cgi-bin...?&I=LX2778&P=7

spiff84 · #12 07-29-2006, 06:12 AM

thanks, yeah i know about them. Wasn't sure they will fit side-by-side 4200s. I think i have the batteries sussed now

spiff84 · #13 07-29-2006, 07:09 PM

ran my brushless TNX today. Considering i haven't got the gearing right yet and i was using very old GP3300s i was very impressed. I had awful interference from the motor (i think), the truck did what it wanted when further than around 15 meters from me. I say it was the motor because when i turned the TNX upside down and walked away it behaved until i hit the throttle, then the servo and motor did what they liked! I moved the receiver and ariel away from the motor and esc, but it didn't really help, think i'll save for Spektrum.
I have a video, but it's 64MB for only 1 minute

it's in .mov format, any ideas for getting it smaller? i'm new to taking movies.

Even though i was limited to range and only used about half throttle it was fast imo, but i haven't seen any other brushless truck in the flesh to compare.

Combatcm · #14 07-30-2006, 04:06 PM

Done

I used the servo mixing for the mechanical brake and I cut all the power to the motor brake. The Dx3 tx has the mix function and it worked great, I just plugged the break servo into the aux channel and dialed in the servo throw.

The castle link is great, all you do is plug it in, change something then go back outside and try it out.

It does rolling wheelies till about 5mph. I even dialed in the throttle limiter AND put it on low timing.

I'd say it's about as fast as the .18 engine, but definately has more low end. The 9s on 8 cells puts balls in this truck for sure.

It gets a little hot, but I have a ubec that powers the fan, I'm going to use another fan for the ESC.

spiff84 · #15 07-30-2006, 05:58 PM

that looks great. i like the use of the tnx gearbox and brake.

Combatcm · #16 07-31-2006, 07:09 PM

Vid

http://s3.photobucket.com/albums/y93...t=tnxdrive.flv

8s is not powerful enough

Micke_b · #17 08-01-2006, 02:32 PM

is that with 8 cells nimh only??? hows the motor temp and esc temp? looks great to me.

Combatcm · #18 08-01-2006, 02:51 PM

Hot and Hotter

The esc could use a fan to stay in check, doesn't thermal during the full runs, just gets really hot. The motor did get really hot untill I put a fan beside it, now it just gets hot.

What really kills it is when second gear kick in. Even though it has pretty incredible acceleration on second gear, it still strains the motor. I'm going to go for the 40T spur, instead of the 38.