2014.09.24, 07:52 AM
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#1
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Moderator
Join Date: Sep 2002
Location: Washington, DC
Posts: 35,480
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Shapeways Spotlight, Mini-Z Subchassis V6 - Audi R8
Yet another astonishing, custom crafted mini-z product that can be found on Shapeways! very interesting to say the least and worthy of sharing with everyone, even if to provoke conversation. if you haven't already, i highly recommend searching shapeways from time to time just to see the stuff people care developing. there is some cool stuff going on out there. who knows, maybe each of us can print on demand manufacturer parts in the future making discontinuation of parts a thing of the past.
today's spotlight
Mini-z Subchassis V6 - Audi R8
From JesseT
About this Product
A motor mount, rear suspension, servo bottom plate and Audi R8 body adapter in one piece designed for the MR03VE Mini-z. It is designed to use a PN-racing brushless motor, and a tri-damper rear suspension. The design incorporates the provision for side dampers from either Atomic (shorter) or PN (longer). The only configuration is middle motor with 97mm-99mm wheelbase. The wheelbase and motor position have eccentric adjustment that provide easy gear mesh adjustment with a very securely locked motor. Excellent for 126dp gearset and high power motors. No guarantees are given for parts fitment, and some parts might need fine trimming. However, the design has worked flawlessly in testing. Enjoy
Image courtesy of Shapeways digital preview.
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2014.09.24, 09:48 AM
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#2
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Registered User
Join Date: Jan 2007
Location: West Chester PA
Posts: 127
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Looks nice.
Does it use a regular T-plate?
What are some of the advantages over a stock VE chassis
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2014.09.24, 12:04 PM
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#3
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Moderator
Join Date: Sep 2002
Location: Washington, DC
Posts: 35,480
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I have no idea. just came across this in a search and though the concept was cool and wanted to share with with everyone else.
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2014.09.24, 01:09 PM
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#4
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Registered User
Join Date: Jan 2007
Location: West Chester PA
Posts: 127
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Contacted designer, will report back.
Last edited by abasualdo; 2014.09.24 at 03:25 PM.
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2014.09.25, 06:27 AM
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#5
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Registered User
Join Date: Jun 2012
Posts: 48
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At the left bit older version that can take any motor but needs PN reconfigurable pod and some custom parts. At the right I believe is V6 chassis.
I think JesseT (whos designs these are) will make a small writeup here and give you a better idea about these. But I can just say that tri-damper equipped JRP link-subchassis and JRP a-arm setups have dominated our fastest lap boards and races for a while now.
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2014.09.25, 06:50 AM
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#6
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Moderator
Join Date: Sep 2002
Location: Washington, DC
Posts: 35,480
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it would be a pleasure to have JesseT provide some insight on the product, design etc.
i would like to know what parts are needed to accompany the underchassis (rear suspension). it's relatively inexpensive so worth a try.
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2014.09.25, 11:56 AM
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#7
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MINI-Z BODY NUT
Join Date: Mar 2003
Location: pa.
Posts: 5,028
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Thanks, looking forward to the info on this.
__________________
MINI-Z BODY NUT
DG DESIGNS - PN RACING - MANTISWORX
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2014.09.25, 03:58 PM
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#8
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Registered User
Join Date: Mar 2012
Posts: 56
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Ok, how to make this story short...
I got into Mini-z around 2 year ago after having a 10 year break from any form of RC racing. When I was younger, I raced 1/10 2wd/4wd off-road, 1/12 on road, and 1/10 touring cars in the time frame from 1985 to 2004 and had gathered some kind of understanding of what could work and what not.
Driving Mini-z cars always made me question the designs available and I was making a lot of one of CNC parts for myself where parts were moved 1mm here and there for better handling. However this was a slow process and only made the car more expensive. One must admit that the Mini-z is rather expensive to begin with, not to think what happens to the price when you exchange everything to aluminum for whatever reason...
The cars were very good already, but with custom everything, very hard to build another one for practice or for a friend. Already quite soon, I realized that the tri-damper was the way to go for suspension. However, I never liked the T-plates, as they seemd to flex at all the wrong places, and didn't have a tweak setting anywhere. For some time I was quite happy with the QteQ 4-ball T-plate that had complete freedom of movement and left the springwork for the springs. Finally the tri-damper didn't need to fight the forces of a T-plate. The downside was that it was quite flexible and prone to develop rear-end steering and slack after a while. Something not very suitable when better and better tire setups very developed at the same time.
By that time, I had already started to use the MR02 A-arm on the MR03, because it was a nice one piece package. It only needed some machining to make it fit the MR03. I had a few front suspension and I loved the fact, that I could change the entire front to a different setup in seconds, by undoing and doing the two screws. Also changing ride height was simpler by shimming, and the geometry was uneffected by this. Nice. May the A-arm be expensive, but I liked the package. To remove the machining work needed and to slightly change the geometry I decided to make my own front suspension main piece for the A-arm setup by 3D printing. When I first assembled the new plastic A-arm front end, I noticed how nice the material was. All the pins went tightly in, no need for E-clips, no need for nuts, securing screws and it was lighter. Also amazingly stiff and it always returned back to shape. No permanent bending and wear, like on the aluminum parts! I was hooked.
So, next started the quest of getting rid of the T-plate for better rear suspension. All 1/12 cars had gone for side links long ago, so it intrigued me. I needed a sidelink Mini-z. So, I made a design of a motor pod, that had extensions connecting to the front bottom plate. In stead of the T-plate, I wanted only one ball to prevent vertical and lateral movement. The links would prevent rear steering. Everyhing else was upto the tri-dampers. The rest of the motor pod consisted of PN reconfigurable pod parts. At track, the car was much more stable and could use more aggressive tires than before.
When I moved to brushless, I started to think that none of the commercially available motor pods were really designed for this power combined with the delicate 126dp gearset. Any bending or moving of the pod parts would rapidly kill the gears. So I went for a completely new rear pod design. The idea was to support the round 17mm brushless motors only and make the motor adjustment and rear axle height adjustment with eccentric cams. This worked. Never earlier had I a car before which was so quiet, and precise to set the gear mesh. Also, after two races and a lot of practicing, I noticed that the original 22teeth pinion I had installed, was still like new. Additionally it was by far the lowest center of gravity car around. I could again increase the front grip levels and still keep the car on four wheels. It was fast. Insanily so at times running 7.2s laps at the PNWC 2014 regional layout. Close friends have wanted similar cars, and it has been a pleasure to see them find more speed with my recipy. I don't mind getting beaten with my own design, much at least, sometimes...
A lot of iterations on all the parts have taken place to slowly get everything into position and correct tolerances. Still, 3d printing cannot match molded parts in accuracy. When assembling, care should be taken with every single fitted part so they fit perfectly. A little trimming, and grinding might be required at times.
Funnily, this thread was posted to the aftermarket chassis subsection, as the only thing I didn't change was the original Kyosho chassis. Perhaps, because I named the rear pod with side links as a "sub-chassis". It doesn't change the fact that it is more or less a motor pod design.
Last edited by JesseT; 2014.09.25 at 04:03 PM.
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2014.09.26, 11:59 AM
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#9
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Registered User
Join Date: Jan 2007
Location: West Chester PA
Posts: 127
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Jesse,
Looks great!
Thanks for posting pics and writeup.
A few more questions?
1)What does the rear motor pod pivot on at the center?
Modified stock mr03 kingpin?
Can you post a pic with the pivot ball plate removed(t-plate holder)
2) What additional parts are needed with the older brushed motor setup?
3) Do the stock Kyosho brushless motors fit your VE sub-chassis?
On a different note, but related to your slot car tire rims for mini-z
http://www.shapeways.com/model/26802...l?materialId=6
Do these only fit Slot-it tires? Will NSR Supergrips for example also work on these rims?
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2014.09.29, 09:17 AM
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#10
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epic procrastinator
Join Date: Jul 2006
Location: Whistler, B.C.
Posts: 2,216
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I'm curious enough to add some questions to the list:
1. In photos, it appears there's a pin acting as a gimbal pivot and yet the small parts show the mount without a gimbal pin. Can you explain what exactly is used to finish this gimbal pivot?
2. I'd like to know if any users have had success with a combination tri shock/damper plates instead of just your tri shock setup?
3. I'd like to know if any of your testers have had success using different front arm setups? I've never been able to find a good balance with the A Arm so I'm curious to find what kind of material removal I'd need to perform with a lower connected pivot bar...
Thanks for your time...looking forward to your responses!
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2014.09.29, 03:14 PM
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#11
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Registered User
Join Date: Mar 2012
Posts: 56
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1)
I've always used a long 10x2 set screw as the pivot pin with the threads grounded away at the end. Have a look at the attached picture. The amount of movement is just a few degrees up and down, so there's no need for a proper sphere really.
2)
You would need the bearing carriers and motor carrier from the PN reconfigurable mount or bought as spares. Also carbon fiber pieces to properly align and hold down the motor carrier.
3)
I would be a hassle. PN is the best brushless motor out there and also pretty much a standard, so the car is built and optimised around it with no compromises.
4)
NSR supergrips are very small and do require a smaller size rim too. I will make a version available.
1. see 1)
2. I think nobody has tried such a combination. And I hope they will not...
3. To use a lower front bar would need the bottom plate to be cut just after the bar. The lower bar will also require the ride height to be raised back to the standard level making the car handle a little worse. I will see later, if I can make a version with the original lower king pin ball mounting positions. It would be interesting from an affordability point of view.
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2014.09.29, 06:14 PM
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#12
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MINI-Z BODY NUT
Join Date: Mar 2003
Location: pa.
Posts: 5,028
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Jessi,
Does the front bumper help with the Honda body on the rails?
__________________
MINI-Z BODY NUT
DG DESIGNS - PN RACING - MANTISWORX
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2014.09.30, 12:35 PM
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#13
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Moderator
Join Date: Dec 2004
Location: Los Angeles (Pasadena), CA, USA
Posts: 2,809
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Wow! I really like the design. Had been considering a similar concept but this was before Shapeways really hit its stride, so no good materials to use. How is the pod deflection left/right under load? The screw-as-pivot idea works fine as both Cowboy and I know but what about during droop? I also thought that 3D printed side blades would compress in strange ways when they're that long. They definitely did in the MRCG, and that was fiberglass. Curious to see yours flexed.
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2014.10.01, 12:40 AM
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#14
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Registered User
Join Date: Mar 2012
Posts: 56
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The rear is very free to move before installing the springs and really doesn't resist against the springs. Much, much less than any lightest T-plate would do. Also it has absolutely no rear steering (deflection), which the light T-plates have plenty of. And as with any disc damperless car, the absorbing has no dead zone or slack.
Light weight and the low center of gravity of the whole car is another thing. The car pictured above I just build for a friend, and it weighed 158g in full running condition before additional weights. Being able to add ~20g to ground level really makes a difference.
All of this makes a car which is not straight alot faster, but much more stabile. This brings consistency. With the added stability, more aggressive tire choice can be used that would upset or traction roll other cars. And there comes the added speed.
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2014.10.03, 01:07 PM
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#15
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Registered User
Join Date: Jun 2002
Location: Redwood City, CA
Posts: 562
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Very interesting looking design Jesse, and I for one would like to give it a whirl. However, I notice that your subchassis seem all to be geared for a particular body, and unfortunately, I'm not really interested in running any of the bodies you have created subchasssis for.
Is it possible to make the front section separately from the subchassis so that it could be adapted to multiple bodies, perhaps by attaching the standard Kyosho front body clip to it?
ianc
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