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Old 2002.10.10, 04:31 PM   #1
pkh
Mini-Z Pro
 
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Join Date: Sep 2002
Location: Allentown, PA
Posts: 56
Micro RS4 RTR Review

Someone asked me to post a review of my Micro RS4 RTR Kit, so here's my initial impression of it. Keep in mind I'm going from a Mini-Z to the Micro RS4, so my views will be skewed accordingly! I've only run it inside my house so far, as it's been wet and raining outside since I got it (and running outside is where it will really perform). If anyone has some specific questions to ask about the RTR version that aren't covered here, feel free to ask away.

First of all, RTR is not quite right, "ALMOST RTR" is more accurate. I say this only because it takes 30+ minutes for a newbie to mount the tires, install the battery pack, etc. to get it running. With the Mini-Z, you just have to screw on the antennas, pop in the batteries, and go (5 mins or so). I ended up putting a very thin film of vaseline between the wheels and the hubs (on the chassis). Otherwise it was virtually impossible to pull the wheels off again!

I was a little dissappointed in the body. It's prepainted with decals on the outside surface, but whoever applied the decals did a half-a$$ job at aligning them. Being used to highly detailed Mini-Z plastic bodies, this flimsy lexan body is not as cool looking.

The turning radius is much larger than the Mini-Z, which makes it a little more difficult to run in the house. However, the ESC has a "feature" that really makes it a pain in the a$$ to run in tight quarters: a 2 second lag going from forward to reverse (see more below). With the Mini-Z, I could go back and forth to work my way out of a tight spot, but this takes forever with this Micro Pro Control ESC! So far this 2 second lag is probably my biggest gripe about this car... very frustrating to me! If anyone knows a hack or a way to reprogram this ESC, I'm all ears!

Now let's jump to the electronics...

ESC:
The RTR kit comes with HPI's Micro Pro Control ESC. This looks like it will handle just about anything I care to throw at it. It will handle 4 to 6 cells (4.8V to 7.2V) and has current ratings of 200A peak and 80A continuous! As I mentioned above, I don't like the 2 second lag going from forward to reverse, though. The ESC spec sheet says that during this 2 second lag, the ESC is braking. At first I tried the brakes on carpeting and didn't see much of an effect, but running fast on a linoleum floor proved that the "brakes" really do work pretty well. Reverse on this ESC is limite to 50% of the max throttle to "maintain controllability" according to the spec sheet (this is not a big deal to me). One interesting thing to note about this ESC is that it uses discrete power MOSFETs, and there appears to be an additional slot in the case and holes on the PC board to accomodate an additional pair of MOSFETs. I am guessing that this may let you double up on the forward drive MOSFETs to lower the on-resistance and increase your top speed (this is only speculation at this point).

Receiver, Servo, & Transmitter:
These are all Airtronics units rebadge as HPI. I'm impressed that there is virtually no glitching of the steering like the Mini-Z (I'm guessing that this is due to the fact the the ESC and the receiver are two separate units, and noise from the ESC is much more isolated from the receiver circuit). The transmitter has less travel in the steering wheel than the Mini-Z transmitter, and much less travel in the reverse portion of the throttle control, both of which I don't like, but I will probably get used to it! Otherwise, the quality and performance of these components seems OK to me so far.

Upgrades I'm currently considering...

I'm thinking of adding a 5th or even 6th AA cell to my Micro. I've got a couple of single AA battery holders from Rat Shack that I can splice in series with the 4 cell AA battery holder. Looks like one will fit on top of the chassis just behind the front wheels, and another will fit next to the receiver. I don't care for the multi-cell packs since there several times more expensive than AAs, and they have much less capacity (granted, they would be lighter). If I do this I'll use battery connectors so I can use either 4 cells or add in the extra cells by swapping plug connections.

Well, there's my long-winded review for what it's worth! I'm not sure how I came across above, but in general I have to say I am happy with my micro, despite my gripes . All wheel drive is very cool! The foam padded tires are also very cool!

Regards,

Paul

Last edited by pkh; 2002.10.10 at 07:44 PM.
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