experimental mini lst suspension

[carmatic]

still need the drivetrain and everything else, no articulation pics because i need to get shorter links to replace those opposite the shocks (the suspension links), would like to get wider offset wheels just to be abit more sure, and i would like to get kimbrough 131 servo savers... right now the steering is chopped right out of the stock mini lst and the steering links are running into the upper chassis links, but with the different location of the ballstuds with the kimbrough savers the steering link will clear them

1/10 scale hex adapters for the mini lst from Country Alloy Works, some type of buggy wheels from HPI and dirt hawg tires ... thats all the 'standard' mini lst stuff i think...
the delrin chassis is a jwcustomwurks dfc-1 made just for me, chassis links are from rc4wd, suspension links are lunsford turnbuckles and t-maxx rod ends, cantilevers are from the pti goliath...

 

[666]

Hate to diss on your idea, but seems like you lose alot of GC like that, not very scale looking, and Mini LST driveline components are crappy.

 

[carmatic]

and last but not least, a big thanks to a certain somebody and his box of assorted aluminum pieces... all the stuff between the mlst gearboxes and the proper 'crawler' sections are built using stuff from inside that box... i still have those cantilevered shock towers you built for me

 

[carmatic]

Hate to diss on your idea, but seems like you lose alot of GC like that, not very scale looking, and Mini LST driveline components are crappy.

its ok, what i really wanted to test was how the weight distribution works during articulation, and see if this suspension can be used to compensate for a higher center of gravity...
there is a solid axle component tied to the articulation between the gearboxes and the chassis, and there is also a double wishbone suspension component which works vertically with respect to the gearboxes...what i would like to see is more stability in the vehicle because of the way the wheels move in relation to the chassis, like what happens when the gearboxes are at different angles and the wheels are at different heights
this is the 'double articulation' which me and a bunch of other guys were talking about in a thread over at one18th over a year ago

the ground clearance under the gearboxes is slightly over one and a half inches with the arms level, how does that compare with what you guys have?

 

[freddyg]

yeah this is a crap idea....wait, except for the fact that its original and has some very cool concepts being tested. I would definitely ditch this project, if you're not careful, you might have some fun trying something new!!! I hate testing new ideas, I'd much rather have what everyone else has.

I think it looks great keep us posted.

 

[carmatic]

on the other hand, i love being original... the whole thing as it is right now, is kinda heavy and im worried how the mini lst's steel gears and those MIP pinions are gonna hold up , much less with the drivetrain, motors, and everything else installed

i have heard that MIP do custom length dogbones, is that true? this thing im building is almost twice as long as a mini lst so im going to need longer driveshafts in the middle... other than those, im planning the rest of the drivetrain to be mini lst, and i cannot find a slider shaft which will take a place in the mini lst drivetrain, but i can install the center tranny in a slightly higher or lower position than it is now so that it keeps the same distance from the front and back gearboxes throughout articulation ...so hopefully i could use a shaft with a fixed length

 

[Mriswith]

My Axial with Panther Cougars (soft foamed and weighted fronts) has 1 3/8" clearance at the diff (lowest) and 1 7/8" (highest) under the axle tubes. The rear is marginally higher with stiffer foams.

Unless I'm missing something it looks like all it does is vary the shock angle though it it's articulation from a softer shallow angle at full droop, to a firmer upright position at full compression. If thats the case it looks like an overly complicated multi valved/rate coil over setup. As an R&D platform I'd like to see how the setup performs.

Fun to try as a design experiment, sure but as a functional rig, not so much. I'd still like to hear how it turns out.

 

[freddyg]

well, i think its a great idea to combine the indy susp with a...a... it doesnt feel right to call it a solid axle center...how about a floating center? and at the same time, using a single set of shocks to provide suspension for both. I guess i've seen something similar with a maxx suspension but it used a set of shocks for the floating center and another set for the indy.

 

[carmatic]

My Axial with Panther Cougars (soft foamed and weighted fronts) has 1 3/8" clearance at the diff (lowest) and 1 7/8" (highest) under the axle tubes. The rear is marginally higher with stiffer foams.

with the arms level, and using my current tires, i am getting a fraction of an inch more ground clearance than you, and thats evenly across from tire to tire ... but then again it is because the mini lst is a scale down from typical crawlers, and so its drivetrain is undersized for my vehicle... lets hope those steel gears will really hold up to all this, if they dont then i will have to replace as much of the aluminum as possible with some sort of plastic or something

Unless I'm missing something it looks like all it does is vary the shock angle though it it's articulation from a softer shallow angle at full droop, to a firmer upright position at full compression.

dont just look at the shocks, but also see the fact that the gearboxes are moving relative to the body, while the wheels are moving relative to the gearbox... when the vehicle is pushed straight down or pulled straight up, it wouldnt matter except for changing the wheelbase, but when there is articulation, what would happen is that one arm will go up, which causes the suspension to pull that side of the gearbox towards the chassis, which would change the angle of that gearbox , which would change the upwards movement of the arm to a diagonal movement, and so on and so on... for the trained eye you will see that the links opposite the shocks are not going to change their altitude too much through the full stroke of the shocks, and thats true... so im planning to buy shorter links to replace those, so as they get pulled inwards by the cantilevers, they will be forced to swing upwards much more...

well, i think its a great idea to combine the indy susp with a...a... it doesnt feel right to call it a solid axle center...how about a floating center? and at the same time, using a single set of shocks to provide suspension for both. I guess i've seen something similar with a maxx suspension but it used a set of shocks for the floating center and another set for the indy.

personally, i call it double articulation

some issues i am having are stuff like there seems to be some resistance to the articulation, maybe if i put ball bearings to support the cantilevers the action will be much smoother ... also the links are rubbing against the rod which they are on, and the lower links are slapping against the surface onto which they are mounted, i hope that shims will solve this... there is some massive binding of the arms with one of the gearboxes which i am not happy about, if i cant find and get rid of it i'll buy a new one, theyre cheap anyways... there are also some badly drilled holes which i will need to fill in with metal epoxy

but the plusses are how the links and shocks have cleared everything around them so well, how i managed to guess the positions of the link mounting points on the chassis, and what im most glad for of all is how it somehow all fit together! this was all done using a dremel and a file... not to mention the drillpress conversion for the dremel, and a bunch of bench vices... ive bought the dremel just for this, and right after the last piece was cut out its speed controller gave in, so it only either went at full speed or its off, no good for plastics anymore

::edit::
this is an articulation shot of what it can do for now

look at the angles of the tyres, and also at the angle of the aluminum bars above the gearboxes... the bar closest to the camera is tilted with respect to the other bar, and the chassis is somewhere in between, its not supposed to be parallel with one of the bars, it looks that way because of the angle... when i fix the problems there will be alot more articulation and the effect will be clearer

 

[freddyg]

the chasis links arent parallel, can you do something to change that? i think that may contribute to the artic problem?

 

[carmatic]

the chasis links arent parallel, can you do something to change that? i think that may contribute to the artic problem?

artic problem? what do you mean by that

i will have to cut out new parts which go onto the sides of the chassis if i want to change the position of the holes, because they are whats holding the links to the main chassis... i wouldnt mind getting like a sheet of delrin and cutting parts out of it, because its alot lighter than aluminum and alot more pleasant to cut through as well, but the rheostat in my dremel is shorting out so i'll have to fix that first before i can cut plastic without making a mess

 

[jwcustomwurks]

Hey..I remember this. Good to see pics"thumbsup"

 

[hairba11]

Speaking of certain someones...

I'm glad to see this thing come to light,

in case you are worried about the gears, my MLST crawler comes in right at 4.5 lbs, 2-ish kg, and I am still using the stock plastic gears with JB Welded spiders.
I haven't run it in a long time, but I still remember the fun of building the thing before I even knew Rccrawler existed.

Anywho,

Looking at the setup and the photos, I think it would almost be better with longer links connecting the A arms to the cantilevers to make more use of the Indy suspension

I think I can see how this moves, let me know if I'm close, I'm visualizing This:

 

[carmatic]

hehe glad to see the 2 people who contributed to this suddenly appear in here
yup, that is indeed exactly how it works

the arm-cantilever links are actually quite a lucky one for me, when the arms are level the cantilevers are pointing just about perfectly horizontally... and this is considering that ive drilled the vertical holes on the large aluminum angles(the ones directly on the gearbox) pretty much at random, and that ive also ordered the lunsford links without measuring anything, and the rod ends ive used just added enough length to the links to match the cantilevers to the arms


here is another pic of the articulation

the round table isnt helping much with the perspective, and neither are all the different angles in this suspension geometry, but both the wheels on the far side are firmly on the table... you can see the far side gearbox and how the arms are articulated on it, while on the near side gearbox you can see the difference in the distance between the arms and the bar, and the difference in angle between the near side gearbox and the chassis becomes abit clearer

maybe a different point of view would help

like the sense of which direction is 'up' is illusory at best, but at least you can see that the wheels are indeed on the table...

what i am looking to do is replace the cantilever-chassis links with shorter ones, so that it gets more articulation from the solid axle component, like because it will swing higher for the same amount of horizontal travel caused by the cantilevers, as well as lower the chassis down abit more to improve the center of gravity... which should make it much more of a crawler than it currently is...
you can already see that the minimum tire-height amounts of travel is already there in its current state, because the military tape is about the same size as the tires... im trying to think just how much more travel can it get, without getting too much solid axle influence and getting noticable torque twist

 

[carmatic]

a closer look at the 'front' of the vehicle... im trying to keep this as mini lst as possible, and that includes the steering

i would take more pictures and stuff but i gotta pack... when i get to my new place you'll get to have a glimpse of it in the background of my pics

 

[hairba11]

so basically are you trying to get a higher level of performance along the lines of this:

or is there more too it?

better be HS81mg's to swing the 2.2's :grin:

 

[carmatic]

thats part of the reason... but also, because the independent suspension component is only sensitive to forces vertical to the gearboxes, so as the gearboxes articulate relative to the direction of gravity, the vehicle's weight will be beared by either the shocks, which will then be compressed, or by the other structural features of the vehicle, which is rigid
hopefully this means that during articulation, the vehicle would 'settle' to a more upright position compared to a normal vehicle

a key part of the suspension is how the cantilever-chassis links are pointing the way they are... because of the low center of rotation, there will be a lot of horizontal movement at the height of the cantilevers, and this horizontal movement is translated by the cantilever-chassis links to compression and extension of the shocks and of the independent suspension component, but with a net compression of the solid axle component because of the particular way that the links and cantilevers are arranged... i think... and that would be a good thing because the weight of the vehicle would cause it to 'lean' into the gradient, rather than being pushed away by it.... i think...