Losi MMT concept/prototyping

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I'm really digging your setup!

What are your plans for the battery?
 

T_Tank

Well-Known Member
Battery is gonna be kinda tricky to figure out will need to run the prototype by my LHS in the area an see what batteries could "fit" without much issue then make a box for it to sit in.

part of the goal down the line would be for folks to be able to buy their own chassis to do a conversion on a mrc on so.. any ideas on a good brand of batteries that don't tend to phase out a size form factor?
 

T_Tank

Well-Known Member
Manage to get the truck into a working roller but have to wedge a traxxas 1/16 battery in there with a small orange rx an novak edge 2s esc an even with a 17.5 shuur speed motor rounded out the green gears >.< I'm wondering if you could reinforce those gears with some thin bits of metal an use jb to fuse the metal to the plastic gear....

Best solution would be to find out what getting diff gears made out of metal would cost which i'm sure would be not cheep but seriously losi... we need some metal gears for the mini lst an mrc
 

T_Tank

Well-Known Member
Trying the experiment on using some small pieces of aluminum to reinforce the vendetta gears to keep them from rounding out.



These bits of aluminum are L shaped but really small an was not easy to dremel sand them to what I figure be a good shape, then used a axle end to guide them in while heating with a soldering iron... You have to be EXTREMELY careful with the heat an also make sure thickness of the face out parts of alum are not to thick so they will not warp the teeth from behind. I got lucky an didn't have any issues so just take your time an you will have some hopefully stronger diff gears.

Will be beating these up today after work will post my findings
 

T_Tank

Well-Known Member
Ok a quick update on those modded reinforced gears. They hold up surprisingly well!... as long as you didnt lock the slipper and hold the truck down.. oops

Also have to look at redesigning the axle for a stronger connection from the axle tube the differential housing snapped the thing clean off on a jump at srs raceway, kinda surprised me as the thickness of the tube walls is 6mm! Chassis has held up well but there will be a revision as i've noticed a possible fail point if you were to crash hard enough.

still want the next deisgn to be a drop in for the mrc housings an still use stock servo plate options but thinking a much more beefy axle.

Anybody have some good links to monster truck axles that have a more traditional ring pinoin gear setup and not the blackwell setup? sofar a zf apl b765 i've seen looks like something I "could" base the next design off

edit

Ok so here is my second shot at a new axle housing





all internal measurements are the same as v2 but v3 has a more complex diff area to help try an stiffen things an will make a modular link mount variant this one is a stocker drop in though length distance on the links an shocks may be a little longer
 
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T_Tank

Well-Known Member
Trans option pictures

So here are few pics of the truck with the mrc an mini T trans just so you can see what kind of room the truck has with those trans options.

First up mrc! with novak three80 motor attached

Did run the truck around with this was about... 10-15mph guess good for a rookie class mt race








And the mini T trans (had binding issues in it.. need to figure that out)

Complete madness with such a low ratio in the trans but need pin style grub screws for the outdrives keep pushing them out of the plastic traxxas universals so unable to really get a idea of top speed but likely.. close to the merv trans or faster.





didn't take a further back side pic with the mini t trans as it sits at the same hieght as the mrc.

Good lord though these trans options make the truck unbelievably light! That... might actually be a problem XD

Edit
Here is a render of the modular mount variant of the axle which has a few options for shock mounting an lower link mounting
 
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T_Tank

Well-Known Member
Revision 3 axle ordered

Ordered the v3 non modular version of the axle an did some minor tweaks to the chassis for better shock angle.

Come on folks give me some opinions good bad or ulgy I'm not just making a one off I want to make this something for folks to build if they want a mini monster!
 

highroller

Well-Known Member
you know I am great at picking people projects apart and I'm not really seeing anything I'd change.
I would love a mini race clod still though. Like a 1/16 ish scale moa full race chassis.
 

T_Tank

Well-Known Member
Awesome guess I'm doing something right!

Ya know I started first on a mrc wide moa axle at first with the goal of being able to use 380 can motors but it got over my head with the transmission internals.. Thought about using a merv unlocked center diff but couldn't think how to deal with the need for drive pins..

But from what I learned with that I got a better start with the mmt.

I'll likely get back to the moa project or make it open source so everyone can contribute to a platform, shoot it could be fun to see what the community would come up with!

Here is a rather old render of the moa axle

 

T_Tank

Well-Known Member
Darn it ya got me thinking about that issue with the merv trans center diff being used for a moa axle an it hit me.. I've seen some traxxas hybrid crawlers where they basically fuse the A arms in position an make it a solid axle with a 4 link.. could probably do that easily with a merv an then you could make variable WIDTH axles! still would need to figure out the transmission more but that in theory could work out fantastically! Like you don't even need to make custom internals you just use the merv drive shafts an cut them down if you want one side shorter then the other so the motor is sitting more center or twin long ones for a really wide axle!

Anyways working on getting the mmt render updated with the new housings an chassis tweaks I should by the end of the week have figured how high up the mrc trans sits in the chassis so I can make a bat tray for the chassis an then make some sort of slide out section you can take out if you use a merv trans.
 

T_Tank

Well-Known Member
nano update but slightly important for testing

finally took apart my novak three80 18.5t motor an rewired in a new sensor harness (that was painful to do >.<) and got some binding fixed in my mini T trans with locker so..

Have another transmission combo to test with the truck!

still uses the stock mrc trans mount but happens a set of screw holes align spot on the plate so this is a super light configuration just need to grab another 45t spur an dig out my 21t pinion an get some more wheel speed.

Also will be going by my LHS to have them order some vendetta sc diff rebuilds so I can make the front an rear diffs unlocked... killed the stock mrc locker...somehow... tried with mini lst gears with bits of alum to help them "grip" the axles an they shattered like glass when powered was applied o.o
 

T_Tank

Well-Known Member
Thanks I really been enjoying dinking around with this truck! wish I had a drill press to put a hole through the mrc outputs so the traxxas shafts can hold onto them better oh well.

On another note would anyone be interested in me releasing the v2 version of my axle as open source on shapeways an tinkercad so they could do what they like with it?
 

T_Tank

Well-Known Member
Axle just arrived!

New axle came in the mail only issue I have is the thin tabs for the link mounts need about .25mm more material around the holes so they don't risk cracking when screwed in otherwise everything fits like a glove (pinion bearings need to be "coaxed" into fitting with a ballpeen)

now for pictures






Mounted up!







So what ya folks think?
 

T_Tank

Well-Known Member
Thanks man I love how it came out!

I like to think it makes the axle a little "stronger" by having it all one part with a seperate diff cover.. I really should think of a way to change it so you don't need to unmount the front of the servo mount so you only need to pull 6 screws to get to the diff over 8
 

T_Tank

Well-Known Member
Currently trying to figure out how to hide a micro servo behind the axle without getting in the way of anything to allow for more scale look.

Any suggestions?
 
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