Project : MERV basher - In search of perfection

[rcaddict]

Alright guys,

I have loved my revo for over a year now but it isn't without its flaws, I decided to take it upon myself using inspiration from other areas to build up and make the ultimate MERV ( in theory)

So my number one fix is going to be a hitting 2 birds with one stone mod.

I am going to CNC machine some custom wishbones, I will be beefing up the arms but also extending the wheel base by a full inch! This will give me better stability, and also help to keep the front down.

The stock wishbone is only 5mm thick, I am going to be using 6mm but of a more flexible composite enabling impact force to be distributed better and not as much transferred into the chassis. Although this contridicts my attempt to increase handeling I want to get the best of both with durability being of a higher priority.

I understand with the more sever UJ angle I will reduce its life, but its a sacrifice I am willing to make.

Here are the cad drawings:

Here is the initial prototypes, these have not been chamfered or a finish pass so the cosmetic quality is quite poor, but it will show you the stance and also confirmed fitment for me (you will notice an extra hump in my CAD drawing due to a slight bind)

and here is how it looks on

The next mod will be adding big bore shocks(similar to Exotek but hopefully a little better)

Thanks and stay tuned!

Edited December 27, 2012 by rcaddict

[svarts]

It looks ace! But i'm worried about drive shaft now you have more stress on it and will snap.

[rcaddict]

It looks ace! But i'm worried about drive shaft now you have more stress on it and will snap.

The angle is about 10 degrees, In theory the UJ should be able to take the extra stress at the expense extra wear reducing service life, however it is a sacrifice I will make.

Should the service life be so dramatic its almost unuseable I can shorten the wheelbase reducing the angle.

The UJ's are not as aggressive angle as the front on full lock so hopefully it should last.

Thanks

[The Dark Knight]

I'll be following this, looks good! Have you thought about designing rear arms like the RPM true trak, so the toe angle is fixed? I emailed RPM about this ages ago and they said it might be in the pipeline but have other projects higher in there priority.

It may be worthwhile thinking about designing an extended chassis in stead of extended arms?

[rcaddict]

I'll be following this, looks good! Have you thought about designing rear arms like the RPM true trak, so the toe angle is fixed? I emailed RPM about this ages ago and they said it might be in the pipeline but have other projects higher in there priority.

It may be worthwhile thinking about designing an extended chassis in stead of extended arms?

I was thinking about a true track kit for the rear yes.

Its something I may still look into, It shouldn't be all too difficult to modify my design to accept a hub.

An extended chassis would be possible, but I don't think it would be feasible for me, the design time and machining time would out weigh the benefits for me unfortunately.

I will certinly look into a 'true track' styled kit.

[svarts]

I found this on traxxas forum

[rcaddict]

Sorry, But I really don't like that at all, looks very bodged and doesn't look like it would be as strong. Another concern is the battery placement and being a little more open, bodyshell choice may also become an issue (although that looks like its been done to accommodate 1/10 TC shells?

Here is my proposed true track kit design, using 3mm and 4mm screws all over vs stock MERV m2 and m2.5.

I know the hub design isn't ideal, however to offset material and machining cost its the best balance i could come up with. I want to make it some what atheistically pleasing too.

Simulation in CAD shows no binding, but lets make one and test it in the real world.

Here is the picture. ( I opted for an alloy hub and HDPE wishbones.

Edited December 27, 2012 by rcaddict

[The Dark Knight]

Looking good dude, I've had an idea though, see where the lower hinge pin is for the hub, you could maybe have a choice of 2 holes so you you could adjust the camber?

[rcaddict]

Hi mate,

I guess its kind of difficult to see but the camber is adjustable via the ball joint on top. It has a threaded rod/turnbuckle which will allow for positive and negative camber adjustments.

I was thinking of making adjustable toe, but I decided against on the basis more complexity = more to break.

i want to keep it as simple as possible, I will order more materials on Monday and start making a prototype system

[rcaddict]

Alright guys, SO I got the other side made up on stock pivot hubs for now (due to lack of materials to make hubs, Materials being ordered Monday)

I took her for a quick spin and...WOW the difference is night and day, all of a sudden the nose wants to stay down, wheelies are controlled (no more back flips on to the roof) HUGE reduction in grip roll, who knew 20mm wheel base could change the car so much?!

The only issue I am currently having is under hard acceleration the car pulls to one side, this is caused by the toe change under spring compression pulling the rear hubs in. A large amount of toe in has fixed it for now but isn't an ideal solution, the tru-track system will eliminate this and in theory should change the handling ten-fold again!

This has been an amazing modification and I think I am on the way to perfection.

I will mock up the tru track system mid next week.

here is some stance photos for you guys (I personally think the extended wheelbase actually looks nicer, a little more fitting?)

[The Dark Knight]

Looking good, are you using the stock driveshafts?

[rcaddict]

Yep, stock drive shafts.

Work well like that

[rcaddict]

Next modification, this really was a spur of the moment thing.

with days becoming darker around 4pm now I decided a set of lights were in order, firstly i tried 2 front facing LED's this didn't really do much of anything if I am honest.

2 light pods from a HPI baja mounted to the front bumper and being supported by my front bumper at the bottom did the trick...actually my eyes are still hurting after looking at them as I turned them on haha

With all the lights off, only the MERV lights are on here...

[Stock_Nitro]

Following this, great to see innovations for the Merv

[rcaddict]

UPDATE

[The Dark Knight]

Coming along nicely, I take it the hubs are made of alloy?

[rcaddict]

Coming along nicely, I take it the hubs are made of alloy?

Yeah, I chose 6083 T6 aluminium, hopefully they should hold out, However the plastic hubs tolerance is less than that of aluminium as a result there is a tiny amount of play since my measurements were almost 'too' accurate, so I am going to put a 0.1 shim behind the hex

Thanks for the compliments

[The Dark Knight]

Nice one, is this your first trial build of the hub? Or have you a bit of trial and error?

Just a thought, might be worth copyrighting your design, I'm really surprised the likes of RPM hasn't produced a True Trak kit yet for the 1/16 Traxxas models.

[rcaddict]

Nice one, is this your first trial build of the hub? Or have you a bit of trial and error?

Just a thought, might be worth copyrighting your design, I'm really surprised the likes of RPM hasn't produced a True Trak kit yet for the 1/16 Traxxas models.

This is the second rear arm revision but the first hub.

I would love to copyright or patent it but I fear the costs of it would be more than the idea is worth, You cannot see in the picture (flash shows it up too much) but tthe hub is in fact ribbed all round the bearing for heat dispation

[rcaddict]

Sorry for not posting this in sections but I just got loads done today and just forgot to post progress so here is a bunch of it all in one.

[The Dark Knight]

Looking nice, is that rod ends you've used on the upper arms? Maybe use pan heads instead of socket heads too?

[rcaddict]

Looking nice, is that rod ends you've used on the upper arms? Maybe use pan heads instead of socket heads too?

They where just what I had in my screw kit at the time, They don't even get close to the wheel so its not a major deal, just look a little silly is all.

[hebby]

Lookin good mate :-)

[Stock_Nitro]

Indeed, it is looking great

Latest version of the rear arms looks like they are longer?

How have the accumulative changes affected the turning circle etc?

Edited January 19, 2013 by Stock_Nitro

[rcaddict]

Indeed, it is looking great

Latest version of the rear arms looks like they are longer?

How have the accumulative changes affected the turning circle etc?

They are only longer to account for the hub/hinge and hinge pin they overall track width is exactly the same. The turning circle does not seem affected(if it is its such a small amount its noticeable) however the stability has increased so much, although it still grip rolls I can take corners at a much higher speed than before.