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View Full Version : New Parts/Designs for MRCG


color01
2009.01.07, 05:35 PM
I've been designing some new parts recently for the MRCG. They may or not make it to production, but at the very least I plan to prototype these and test them out. :)


New flex plates and rear pod lower plate:

http://img340.imageshack.us/img340/8837/01ilf9.jpg

In theory, with these longer but thicker flex plates, we'll get more bump stiffness, while maintaining the same roll resistance. The addition of a second mounting screw on the rear pod keeps the flex plates aligned even in a bad crash.


Rocker-arm dynamic strut system:

http://img230.imageshack.us/img230/9963/01gyy6.jpg

http://img519.imageshack.us/img519/6056/01hdk9.jpg

Very similar to a 1/12 front suspension, just packaged a bit differently. Springs are mounted on threaded nuts/perches for infinite preload adjustment. Adds 2 degrees of caster for stability, but at the same time reduces stiction and adds a small amount of dynamic caster and camber for more steering. Approx. 8mm lower than the standard front suspension. Compatible with standard MR02 knuckles, and uses a similar tierod mounting style as the InZane P28. Servo strap makes a nice place to put a Giro-Z transponder. I'm very excited to try this out, it won't cost a lot to manufacture but the potential is enormous. :)

atallfunguy
2009.01.07, 05:39 PM
B,

Looks promising.

Slipstream
2009.01.08, 12:37 AM
What are the front upper arms pivoting on? Screws through elastic bushings? You can look at my Scalpel if you want to get ideas. It very similar.

color01
2009.01.08, 01:21 AM
Right on the mark, Willie, the pivot's formed by two silicone o-rings and a screw. I don't think there's enough suspension travel used to warrant a ball nut/stud, so I took the simpler route. I'm still looking around to see if there's a better small-size pivot with more travel (there's enough like this, but more would be nice) but for now this is OK. I'm trying to figure out a better steering setup that has more accurate Ackerman control and is less susceptible to servo horn flex.

http://img386.imageshack.us/img386/9094/01jum8.jpg

I have the Scalpel manual, so I know how its front suspension works. :) What do you think of it though, is it sensitive to spring changes and precise enough for racing?

Slipstream
2009.01.08, 01:52 AM
What I would be concerned with is if the durometer of the elastic pieces are stiffer than the spring someone is using then the it renders the spring useless. The softest you can get the front end is how much you can compress those bushings. If you use too soft bushings then they won't locate and hold the arm very well.

The scalpel is a larger scale and the arms are longer so springs and bushings can be stiffer and there's more leverage to compress its bushings. I don't how this would translate shrunken to mini z size.

On the 12th scale AE front end a pivot pin on the upper arm is used so there is no resistance other than the friction between the pin and arm (polish your pins :) )

From your pictures it looks like you just have to machine the arms and everything else can be off the shelf (Ok chassis mod require) so you can try it.

I guess you looked into the Xray M18 and decided against the pivot ball method.

color01
2009.01.08, 02:31 AM
The bushings are pretty hard, but I picked a size that offers as little resistance as possible to the arm's movement.

Pivot balls take up too much space, I have an idea that involves pins but it means custom-machined aluminum parts. It may be necessary though so I'll keep churning out designs. A full-on dynamic strut system is not a bad idea at all. :)

jetnjme
2009.01.08, 12:20 PM
That looks very nice.

color01
2009.01.09, 09:02 PM
I have figured out a way to use hinge pins with this new suspension idea. However, it is an absolute pain to CAD. So while I let that design sit, here is the wide front end (WFE, to avoid saying WTF :p) set designed for the MRCG.

http://img229.imageshack.us/img229/2835/01knw6.jpg

The set includes the upper bar, two lower L-arms and a longer tierod. This wide front end adds 1.5mm of effective offset for more responsive handling, and then adds 2 degrees of caster for smoother handling and more aggressive corner exit steering.

I chose to use 1.5mm offset instead of 2mm (i.e. Reflex's WTF) so that you can use 0N instead of -1N front rims with currently popular racing bodies (SC430, Super GT 350Z, etc). 0N rims are far easier to find so I took the 0.5mm compromise.

With +1N front rims this front end will work with the pan cars and the new longtail McLaren F1's. With -1N rims the chassis will fit under pretty much any MR02 body.

This wide front end set will definitely be prototyped, but again production is a big ??? mark.

eztuner12
2009.01.10, 08:00 PM
Hi Brian
Looking good:eek:, this could well be a front-end system for your 4WD project.
Regarding the arms bushings (red on the blueprint) arenít these going to generate said to said and front to rear movement plus wear-out due to friction?:confused:
Perchance a pivot ball as the ones on the steering system will control these undesirable movements & wear-out and just move up & down, as you want.
Cheers

color01
2009.01.11, 04:06 AM
*Shrug* I don't know, but after talking to PN about the costs of producing so many small parts commercially, I'm certain that my dynamic strut front suspension won't make it to market. Looks like I got carried away designing useless stuff. :( Which means I don't have any more reason to prototype it, as I have to keep my testing to items/parts that I can give to you guys. I.e. the standard front end, etc.

The wide front end upgrade is much more likely to be produced, but it's only going to happen if all the MRCG kits currently in stock get sold out, and on top of that there's enough demand for a WFT kit. Otherwise I or PN or anyone else can't justify making such a small run of special parts.

eztuner12
2009.01.11, 10:17 AM
*Shrug* I don't know, but after talking to PN about the costs of producing so many small parts commercially, I'm certain that my dynamic strut front suspension won't make it to market. Looks like I got carried away designing useless stuff. :( Which means I don't have any more reason to prototype it, as I have to keep my testing to items/parts that I can give to you guys. I.e. the standard front end, etc.

The wide front end upgrade is much more likely to be produced, but it's only going to happen if all the MRCG kits currently in stock get sold out, and on top of that there's enough demand for a WFT kit. Otherwise I or PN or anyone else can't justify making such a small run of special parts.

Perhaps there is a factory in China that world certainly do this parts less costly
Cheers man:):):D
http://www.made-in-china.com/showroom/yqhardware

http://vancouver.kijiji.ca/c-services-skilled-trades-Welding-Fabrication-Repairs-Production-Runs-CNC-Machining-W0QQAdIdZ93192174

http://www.onerateads.com/RC-370.htm

http://www.onerateads.com/RC-370.htm

http://www.alibaba.com/showroom/RC_Parts.html

http://www.manufacturers.com.tw/showroom-5498-4-5-0-0.php

Many more on the net!

skyler
2009.01.11, 01:12 PM
*Shrug* I don't know, but after talking to PN about the costs of producing so many small parts commercially, I'm certain that my dynamic strut front suspension won't make it to market. Looks like I got carried away designing useless stuff. :( Which means I don't have any more reason to prototype it, as I have to keep my testing to items/parts that I can give to you guys. I.e. the standard front end, etc.

The wide front end upgrade is much more likely to be produced, but it's only going to happen if all the MRCG kits currently in stock get sold out, and on top of that there's enough demand for a WFT kit. Otherwise I or PN or anyone else can't justify making such a small run of special parts.

Brain, RC Kenon has been sold out of your car for weeks now. I hope they produce more kits

color01
2009.01.11, 03:43 PM
Ah I just noticed that, thanks Skyler. :)

Richard- Of the ~45 MRCG's currently out on the market, maybe 5 of the customers will want a WFT set enough to pay for one. So... production seems highly unlikely, and looking for a manufacturer won't do me much good (except for a prototype, maybe, but I have my own CNC mill!).

skyler
2009.03.07, 04:37 PM
*Shrug* I don't know, but after talking to PN about the costs of producing so many small parts commercially, I'm certain that my dynamic strut front suspension won't make it to market. Looks like I got carried away designing useless stuff. :( Which means I don't have any more reason to prototype it, as I have to keep my testing to items/parts that I can give to you guys. I.e. the standard front end, etc.

The wide front end upgrade is much more likely to be produced, but it's only going to happen if all the MRCG kits currently in stock get sold out, and on top of that there's enough demand for a WFT kit. Otherwise I or PN or anyone else can't justify making such a small run of special parts.

Hi Brian, Phillip doesn't want to make a bunch of extra small parts but what if you released another complete car with your new ideas?

lillesmurf
2009.03.31, 08:48 AM
I am not running 1/28 yet but have seen the MRCG which has a lot of good ideas. I am just waiting for my local club getting to a new place where we also can get a mini z/1:28 track.;)

My thought is that the PN Racing Mini-Z MR02 Double A-Arm Front Suspension can make the MRCG much more like a 1/12 car?

Have you tried it? and also how many grams are you then adding if you can get it modified to the MRCG?

I dont now how this would affect the camber, bump stear or other thing in the front!

hrdrvr
2009.03.31, 09:19 AM
Brian, I was thinking this same thing, just now. I know youve probably allready thought of it, and ae allready working it out in your head :D

eztuner12
2009.03.31, 03:10 PM
As I remember, he had considered from the beginning. This young man has a very advanced mind in mini-RC design.;)
Cheers

jonnywachter
2009.03.31, 04:30 PM
I let you in on where I got the pivot balls, so let's see an active strut front end! The car will pretty much be a mini 1/12th scale.