ph2t
Forum Replies Created
-
Nah mate, the servo is just fine. The key is in the feedback potentiometer in the servo you choose to butcher/adapt. The one I used (GWS Pico Servo) uses a 5K pot in the feedback arm so it was more suited to the 5K pot that’s in the miniz steering assembly.
You can try and put a small valued resistor in series with the motor to reduce the current (and therefore speed and torque) that the servo motor responds with. This may work for you.
The resistor in the pics comes with the GWS PCB, I didn’t add it. Although this is another trick that can be used to help get the correct slew (ie: side to side motion with the full extents) for feedback. Betty knows about this, he did something similar in another project (which I forget at the moment).
Yes, 1 cell for compartment. So it’s only a 7.4V 300mAh pack. The funny thing is though that the runtime is still excellent because the larger brushless motor draws less current buyt delivers more torque than it’s 130 sized brushed counterparts.
My AAA’s aren’t even warm after a long run!
This may change though when I get my new brushless motor in from Razor motors. Here’s an excerpt from a postmade by another member (CowboySIR) on another forum I’m on and the same thread there:
Quote:I think i may have found something for you to take a gander at ph2tty…
The company is called Razor Motors out of Santa Barbara.
Diameter:19.5mm
Length: 26.8mm
Shaft:2mm 😈
Kv:5800
weight: 25gramsI compared size to a standard 130 motor and it’s almost exactly the same length and width(compared to the fat width of a 130). On the can I’m having trouble deciphering the “0.7A”…I’m guessing the no load current?
I hopefully will try a similar construct…and I hope to find this baby fits an MM mount.
edit: check the 130 BL thread for a fitment comparison.
can’t wait for this bugger to come in…….
@klims 225599 wrote:
nice work man! can wait to see some action shots.
which LiPo cells did you go for?
and is there any reason you didn’t use the pinions available in the ausmicro shop for 1/16 buggy? checked mine and they seem to mesh alright.
those pinions are 2.3mm shaft or 2mm? I used Hyperion 300mAh lipos in the end, 20C!!!!
OK, here’s another update.
On 4 cells it can be a little sporadic in it’s throttle if pushed hard. Using the mamba esc settings to reduce the power to the motor seems to help with this. Also, putting the cap back on helped with smoothing things out.
Of course the original has gone the way of the dodo and has a surface mount capacitor put in it’s place.
The cap I’m using is a 330uF 6.3V cap. Yes it is below the operating voltage for the lipo but it works. You can push V ratings on caps a bit, done it stacks over the years, but don’t expect ’em to work EVERYTIME, just 99% of the time, lol…..
Making it fit was a challenge, like everything else in this anorexic chassis……
So it’s all good now.
I also looked into adding an extra 3 pin port to plug the Mamba-25 external USB link (CastleLINK), but it would of involved including another switch (to isolate the mamba from the rest for the setup for programming purposes) and socket so the space ran out pretty quickly. Esentially I’ve had to learn to program it via the “beep” method, lol… Painful at first it was but after a while I got used to it.
Finally though I got some freakin’ video down! 😈
Brushless mr-02 AVI
8.7MB, DivX, AVI format, 480×272.(You need DivX/XViD codecs to view this vid, MPEG4 ftw!)
Enjoy!
ph2t.
OK. I found that if I use the stock kyosho mr-02 hplate instead I have now reduced the bouncing a fair bit and made it more drivable in the corners.
The cf hplates are too rigid to allow the oil shock to dampen properly. With the plastic hplate though it can flex more and allow the oil shock to do it’s work.
Also, once in the shell the rear end fits with no issue!
Here’s another photo. i’ve put on the wheels from the audi autoscale (30deg ATOMIC groove on the front, soft GQ foams on the rear, trued of course)..
And here’s one with the shell on. You’d never know she was brushless….
I also full rebuilt the oit shock and put in ATOMIC 1000 mini-z shock oil. All my other grade oils were just too thin. Now the oil shock finally dampens earlier than before on the older oil.
So, I’ve got a few other things but for most of it this setup is now done. 🙂
What I’m finding is that lack of dampening is the issue. The “springyness” of the h-plate is the main culprit. Couple this with the weight of the motor and the rear end just bounces around. Even still with the oil shock although it’s less.
I’ll try a spring on the oil shock and may install the damper shock system with the oil shocked piggy backed on top. I’ll see how I go. I think though at the end of the day, on anything but RCP, this setup is not gonna get long term traction. We’ll see, I need to work on the rear end a bit more to lessen this problem.
If I put some weights up the front, will this help at all? Not in the traditional case argued earlier in this thread but one to stop the rear “bouncy boucdy” that’s happening…..
On a seperate note, I got futher finding an ideal pinion for the 2.3mm shaft. I’m now got installed the GPM pinion for the Half8 stock motor (which is Kyosho 2.3mm !). Got rid of the foil lining the shaft so it’s a true fit now. 🙂
The ball diff will help I reakon with smoothing out the ride. Some of the “bouncy bouncy” is partly to do with the gear diff and it’s no mucking around takeoff, lol….
I’ve also got to put some camber steering knuckles in, I’m running stock at the moment on Ezno offsets. The offset will change eventually depending on which shell it goes into…..
Anyways, here’s a list of pinions that will work with 2.3mm shaft brushless motors.
GPM (#TMIF012T) Titanium Motor Gear (12T) -1pc (TMIF012T)
11T Alloy Motor Gear (for 380 Motor) (Y–021)
DO NOT BUY THESE! (even though it says 2.3mm shaft, the pitch on the gears is a bit wider than the spur gear)
MB4 Alu. Motor Gear – 12T (for 2.3mm rotor) (MB-017)
MB4 Alu. Motor Gear – 14T (for 2.3mm rotor) (MB-018)And on it goes……
OK. Gots more done today. 🙂
I got the setup completed in it’s first revision. lol. nothing is final yet.
On 4 cells it is quite “fast”. It matches a typical PN S03 setup for an ’02. Steering is suprisingly good and consistent. I definately noticed the weight though and being an RM setup it’s even more pronounced.
Current gearing is 12t pinion, stock gear diff. I get 30kph on the speed checker on 4 cells. 50kph on 6.
At first it bounced around on the concrete like a crazy bugger so I’ve installed an oil shock to help dampen that. I may change h-plates as well. I’m running a medium thickness one at the moment. We’ll see….
The oil shock is sitting a bit too high for my liking at the moment. I got to get the right bits to fit, lol…
You can see the mamba-25 taking up pretty much all of the “penthouse level” space within the guts of the ’02 chassis, lol…. the poor GWS servo PCB is wedged in beween the mamba and the steering motor, poor bugger, lol….
And here’s a rear shot showing how this bigarse brushless motor sits, lol…
More to come, video to shoot soon, hopefully!!!
lipo is in the mail, lol…
ph2t.
