1/6 Scale RC Mini Project

[Derek]

First off, I'd just like to say that this is not my project, lol. My hands are quite full with my own ideas and projects. This project is something that my Dad is working on. I'm sure you're asking, "Then why doesn't your Dad start the thread?" Well, he's just unsure as to what to ask to start the thread, so I'm starting it....I'm sure he'll chime in later.

Dad has a 1/6 scale RC Mini that he got for next to cheap. I dont have a pic of the car from him. Perhaps he can post a few pics. Here is a link to a very similar car:

http://www.overstock.com/Sports-Toys/1- ... oduct.html

Now...the project involves something that he and I have already done twice before. Removing the stock "toy" motor, rx, brushed esc, and steering mechanism. Adding a brushless motor and esc, 2.4ghz rx, and a steering servo. This mod worked really well on two previous projects so he wants to do the same thing to this Mini. No problem....we can do that. Here's where some of the questions come in...keeping in mind that this Mini has "toy grade" electronics in it, I can't find any specs on the motor.....more specifically, the KV rating. We have looked at some of my usual online parts stores and we have found some motors that have the same or similar outer diameter and shaft size, starting at 3000kv and up. I did browse through the Rock Crawler section and found a 1200kv that can run on 7-12volts. Dad isn't wanting a "speed deamon" at all. He's very much looking for a scale-runner. Basically, just giving the Mini a bit more "get-up-and-go".

I imagine any of the 3000+ kv motors, for 1/8 scale cars, would suffice but I know that he'd want to turn down the throttle curve because he's NOT wanting a "balls-to-the-walls" screamer.

Would anyone here have any suggestions for a decent motor/esc combo to get my Dad's Mini moving faster?

[west0618]

Hello,
As Derek mentioned I am not after a speed demon...just something better than stock. The car is a Radio Shack Mini Cooper that weighs in at just over 9 pounds stock. That being said it is amazing the crap brushed motor in it even made it move as well as it did. Any motor of equal or larger size can only be an improvement. The stock motor pictures is about 27.6 mm in diameter.

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Yesterday I turned what would equal a 36 mm motor out of wood(SEE PICTURES) to slip in place of the old motor to see if there was clearance to go this big. I will let you know as soon as I can get back to it. It would be a simple matter to mill off the gearbox to accept the larger motor but I don't want to go hacking away at this if it will not fit the car when I am done. I'd stay with a 1" diameter motor first. Even that would be better than stock.

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Mini002.JPG (32.43 KiB) Viewed 6538 times

[west0618]

OK, I finally stopped other projects long enough to get on top of this one since the question at hand is..."Just how big of a motor can I put in this Mini Cooper?" The answer is at least one typical in size to the 36mm - 37mm diameter motor with minor room to spare. I understand this opens up the possibilities tremendously. The current shaft size is approx.(with calipers...I'll tell better when I remove the pinion gear.) is 2.2mm. This gear can be bored out and a set screw installed if needed. What I am looking for is the MOST power I can get and to reach speeds of 60-80 MPH scale.(ideally) 40-50 MPH scale would most likely work for my purposes. I'd rather have too much of each and trim it back in the transmitter to keep from tearing up the gears.
But my wooden mock up of a motor served its purpose VERY well and I have no doubt this size motor will fit with minimal modifications. The recess in the molding of the bottom and the trunk interior leaves a good .100" clearance at the closest point to the "wooden" motor.

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I know between Derek and the rest of you I will get the best advise for the best motor. Then the fun part...making it WORK.

[west0618]

I probably should have added I plan to use the existing 9.6 volt powerpack and see what run time I get. If I am missing something else please let me know.

[Tony]

Been browsing the web for motors, wow there's thousands of the things out there... I wouldn't really know what motor to put in a car but this one seems to fit the physical size requirements... I'm sure Derek can confirm if it's any good

http://hobbyking.com/hobbyking/store/__ ... unner.html

[Derek]

I really don't think it will be an issue of "making it work" at all. I think the issue is going to be "what kv value is best suitable". Normally when Im faced with an issue like this, with my planes, I just take the dimensions of my plane.....search Hobby King planes with similar specs and get a matching motor. That thought process worked out brilliantly with my Blue Cub STOL. But...since HK doesn't have a 1/6 scale car to compare to, my decision making is being challenged.

I've just spent a few minutes with Dad on Skype, searching HK for a motor and esc. We've decided on a 3900kv inrunner and a 60amp speed controller. Unfortunately, they will be coming from the International warehouse so it will take a bit to get here. Fortunately, Dad is much more patient than I am, so he's happy!

[wolfman76]

Been browsing the web for motors, wow there's thousands of the things out there... I wouldn't really know what motor to put in a car but this one seems to fit the physical size requirements... I'm sure Derek can confirm if it's any good

http://hobbyking.com/hobbyking/store/__ ... unner.html

i have a 5300kv motor in my 1/18th Dromida and to say the least i run a 45 tooth aluminum spur gear and 13t brass pinion gear on a 3s lipo seeing as a brushless motor has to be run by a lipo otherwise it will keep cutting out on you. It has a great deat deal of torque also i have already stripped out 2 spurs and pinions they need to be hardened steel you be better suited using a 2s pack with i think mine is a 25amp esc you are looking at around on 2s probably round 40-50mph actual speed might be estimating a little high but not much my truck has a top speed of 60 on the 3s. i think that should be a good choice for your car as you said you can tame down the speeds in the tx depending on what tx you use sounds like a heck of a project can't wait to see the end results and some video. here is another option for you http://www.hobbyking.com/hobbyking/stor ... 00kv_.html

[Derek]

Dad and I need to update this thread, lol. He ordered a motor and esc. He got it installed into the Mini and it's MUCH faster than what it was before, lol. MUCH FASTER! I'll see if I can find the video that showed how it ran before and I'll show the video after the upgrades.

[Tony]

Look forward to seeing those D.

[Derek]

Dad has another thread called "1/6th Mini Cooper Conversion". In that thread, you can see a 21 second video of how fast the Mini was, at full throttle, with the original equipment. Then there are some pictures where Dad illustrates some of the changes made and then there is a video that is nearly 8 minutes long that shows the Mini after the new equipment has been installed. It's really impressive. I do remember Dad saying that he really couldn't show the Mini going top speed because he was videoing with the camera on a tripod so the Mini is only really shown going in bursts. He and I will have to get together and I'll run the camera for him so that we can show the Mini at it's best.

Here is the thread that I'm talking about:

http://rc-hangout.com/forum/viewtopic.p ... 895#p16895

[wolfman76]

Nice can't wait to see it what motor esc he choose

[west0618]

All the particulars are in my build log...ESC, motor, servo, Lipo, receiver...

SEE the link Derek has in two posts above. (I have to learn how he did that link.)

If I missed something, please let me know.

D's Dad