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redshift 07.30.2010 08:58 PM

My New Build
 
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Maxx Mutation, meet your replacement.

This one was started the end of 2009, and was originally going to be a twin inline outrunner chassis. I ended up deciding against that for numerous reasons. Simplicity was still a design priority however, so that meant it would not have a transmission. But being a pure basher, and not a racer, a center diff was not that appealing to me. I briefly considered a belt drive, specifically SDP-SI's new Conidrive series, but the available ratios would not have been easy to design around (driven pulley diameter and belt length). My next choice was Mod 1 gears, and the LST2's 63T spur fit the bill. Enough diameter to the keep the stress radius to a minimum. And keep it plastic hopefully, knowing I could switch to steel if needed. So my next move was drawing up the motor mount, which is a stressed member in this case. It is made of 1/2" aluminum, and I knew I wanted a centerdrive with an 8mm shaft. Having 1/2" to play with I went ahead and used two 8x16 bearings, where one would have been more than adequate.

redshift 07.30.2010 09:04 PM

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Next was the centershaft, no question this would be stainless, and I cut this out of a 5 or 6 pound chunk of 2.5" 304. If you were wondering, ten hours were spent on this part alone. I had made 8mm drive cups out of air-hardening for use with the outrunner (Mike was out of them at the time) so those are now being used on the centershaft.

Lots of photos to come... keep watching :wink:

redshift 07.31.2010 03:25 PM

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The motor mount was done knowing what I wanted to do for a chassis, obviously. :) And at that point I had a CC 1520 in mind. The idea of that motor hanging on two 3mm screws didn't sit well with me, so all four holes would be used. That's why the screw slots in the motor mount are so long.

I found where the pinion (RCM of course!) would sit on the shaft and made a ball divit with a diamond ball burr. I consider this a must to not have issues with the pinion. A tiny amount of red Loctite on the pinion setcrew, and it's trouble-free.

redshift 07.31.2010 03:32 PM

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On to the chassis...

Square tube is the simplest and strongest backbone, and after finding my dimensions I welded some chunks of aluminum onto the tubes. Four on each end, that would have gaps subsequently milled out, then end-drilled. The welds were then rough-cleaned-up using both inner and outer radius mills, and the setscrew pin retainers drilled and tapped. Next up was the joiner plate holes, the joiner plates themselves, and the provisions for the motor mount and aft bearing block were then done. As you'll imagine, this was a ton of work... and I still have finish work, mostly on the A-arm pivots.

redshift 07.31.2010 03:36 PM

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More...

redshift 07.31.2010 03:41 PM

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The main tube is 1.75" outside, 1.5" inside, 1/8" wall. Joiner plates are 1/8" thick as well.

redshift 07.31.2010 03:48 PM

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Coming together now :yes:

redshift 07.31.2010 03:54 PM

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I then made 'cartridges' for the diffs, these were milled out of plastic. The square end blocks with the hole for the diff input stays intact and serves as a stop for the two side pieces when installing the diff. I am using 10-32 blind nuts in the side pieces, because the end chassis holes will also be bumper mounts. Those will take far more torque than the 1/8" aluminum tapped out, and are replaceable. Bumpers have yet to be made, too many ideas and I can't settle on one, kinda frustrating!

redshift 07.31.2010 04:04 PM

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Then I had to come up with some half-ass battery holders. These will likely be changed, still a ways to go on finishing this one up. More to come!

Byte 07.31.2010 04:10 PM

.... :surprised::surprised::surprised:

Bondonutz 07.31.2010 04:34 PM

Very Impressive work so far Bro, Looking great !

magman 07.31.2010 05:57 PM

Holy shiz that is nice work. Curious to see what your ride weighs when done

redshift 07.31.2010 08:23 PM

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Thanks guys :)

I took a fair amount of time looking at various manufacturer's suspension parts, and settled on the LST2/Muggy bits. Prices are better than what I was used to seeing with Traxxas parts, by a lot. And I definitely wanted away from the Traxxas knuckle setup, so next up, suspension. I knew I wanted a laydown shock angle to keep the towers short. Experimenting a little, I figured out I didn't need towers at all. Yes, some Maxx parts found new life here. And already having the heavy Trinity springs made this work. I actually changed nothing other than preload spacers, they still have 45wt silicone, and single hole pistons. Only 4 of them vs. 8 on the Maxx. Delrin spacers were made to take up the clearance on the 4mm pin on top, and I made the lower shock mounts to get my ride height, those still need some finish work. The suspension is very Revo-ish feeling now, very compliant without being undersprung. In fact I liken it to Revo suspension without the cantilever linkages. The results here were far better than expected! No towers means I have unlimited options for body layouts, so that's a huge plus.

redshift 07.31.2010 08:29 PM

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Few more...

redshift 07.31.2010 08:38 PM

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And the steering. I bought the Muggy bellcrank setup on linc's advice, but I could not make it work on this chassis without the bellcrank lower pivots ending up over 1/4" below the bottom of the chassis. So then I got experimenting some more (this was actually a long process) and finally landed on a fully independent servo setup. The huge advantage of this is significantly reduced slop, because there are four fewer joints to create play. The downside is the servo horn becomes the sacrificial part. I tried running twin Ofna HD servo savers and that had the tendency to pull the front wheels into excessive toe-in on throttle, and toe-out on braking. So no go, had to be servo-saverless. Muggy owners will know at a certain point the end of the bellcrank contacts the upper A-arm. The Hitec horns I'm using are about 10mm further back from the diff center, which did not change bumpsteer, and no contact!

Wheels are next...

Bondonutz 07.31.2010 08:38 PM

Interesting shock set up ? Do you think the four little shocks will enough for the complete truck ? It's still gonna be 10-11lbs when complete, I was woundering if a heavier duty front buggy 1/8scale shocks might be better ? IDK.

Yes, very Revo-ish, I really like the looks of the lay out.

Very nice job of fabricating my friend.

You could also swap sides and turn around the rear arms so the rear shocks would be on the other end as well ? Lot you can do with how you put everything together, pretty slick indeed.

EDIT, what size bolts did you use for the pin replacement. I really like that idea even tho I never had probs with loosing E-clips.

redshift 07.31.2010 08:58 PM

Quote:

Originally Posted by Bondonutz (Post 375233)
what size bolts did you use for the pin replacement. I really like that idea even tho I never had probs with loosing E-clips.

Those are the ST Racing set, 4mm shoulder bolts. They're kinda pricey but I ponied up the cash for them because I have a longstanding hatred of e clips:lol:

I actually had the rear shocks on the rear side, but decided they'd be much better protected on the front.

As for the Bigbores, they have worked extremely well in the 15 or so test runs I've done so far. I did intend to get a set of Ofna shocks, but these are working so well I've stopped thinking about changing them. The preload spacers are not on them in the pics because the boots need replacing and they need to come apart again. The rear squats the slightest bit on throttle stabs, which makes it less wheelie-prone. But the 1520 on 6S will throw it up
with it's 14.4" wheelbase still. It's geared for roughly 38 mph and it gets there in about 10 feet, way impressive. The motor and MMM are barely cracking 100 or 105 the whole run. I haven't weighed it yet magman, but with the 1520 weight is really not an issue:party:

Fast5sRevo88 08.01.2010 12:23 PM

:surprised::surprised::surprised::oops:pissed myself:whip::surprised::surprised:

The Cow 08.01.2010 12:41 PM

WOW.. This makes me all mushy inside!! :surprised:

Nice job!

Heath

magman 08.01.2010 04:09 PM

You are right w/the 1520 you should not have any probs...I have my 1520 in my truggy

redshift 08.02.2010 07:44 PM

Quote:

Originally Posted by The Cow (Post 375285)
This makes me all mushy inside!!

Not sure if that's good?

I got a chance to run it in the woods yesterday, and I have some video from it but not of it, buddy's OBV cam didn't save the file...

The 1520 is the perfect motor for this, I have nothing but praise. The power is just awesome. I have it geared conservatively, because it's running on two 3S 30C 2200s. I'm getting over 12 minutes, and I don't intend to get bigger packs, I have 3 sets and they charge in 15 minutes :) The efficiency compared to my old 9XL is... well it doesn't compare. Worth every penny without any doubt. So as it is, I could gear it to the moon with higher capacity packs. The Losi plastic spur is showing no sign of stress or wear with about 18 runs now, the last 6 or so runs very hard on throttle and brakes. I have to be extremely careful as the MMM is somewhat vulnerable. I need a lid, quick like. Very happy so far, just wish I had the lost video from yesterday, I'll be getting more. I'll try to get some RTR pics this week, wheels and everything in the daylight.

Byte 08.03.2010 05:35 PM

Quote:

Originally Posted by redshift (Post 375422)
Not sure if that's good?

I got a chance to run it in the woods yesterday, and I have some video from it but not of it, buddy's OBV cam didn't save the file...

The 1520 is the perfect motor for this, I have nothing but praise. The power is just awesome. I have it geared conservatively, because it's running on two 3S 30C 2200s. I'm getting over 12 minutes, and I don't intend to get bigger packs, I have 3 sets and they charge in 15 minutes :) The efficiency compared to my old 9XL is... well it doesn't compare. Worth every penny without any doubt. So as it is, I could gear it to the moon with higher capacity packs. The Losi plastic spur is showing no sign of stress or wear with about 18 runs now, the last 6 or so runs very hard on throttle and brakes. I have to be extremely careful as the MMM is somewhat vulnerable. I need a lid, quick like. Very happy so far, just wish I had the lost video from yesterday, I'll be getting more. I'll try to get some RTR pics this week, wheels and everything in the daylight.


Niceeeeee :)

Bondonutz 08.03.2010 08:07 PM

Video and RTR pics !
Tired of waiting !

I bet your happy with that 1520 on 6s, with the power and efficentcy.
It's a seriously potent combo ! ! ! !

I was able to score the shoulder bolts I needed to replace the pins here in town. Not sure of the grade but it's all stainless steel. I got the 8 bolts, flat washers and nylock nuts w/tax for $8.05 out the door.

redshift 08.03.2010 09:19 PM

That's a way better deal. The ST bolts are like twice that and are steel. They are rusting from the humidity! I will be putting some light oil on them... I got looking at LST/Mug part upgrades while I was making an order, think they were from Amain. Anyway being plain steel I can't really recommend them. Nothing on this truck is supposed to be rusting dammit! Still better than e clips IMO...

A few other items of mention, the truck (thing) as it sits vaguely resembles a pickup truck... that's not the intent and there's about a zero chance it'll be a truck. The idea is to cap off the sides where the spur protrudes, and the spur/pinion area, to make the gears and both center cvds dust-tight. That will leave only the outdrives to deal with after a good sand blast. There will be a plastic bottom piece as soon as I decide whether to make the packs top or bottom loading. The aluminum will be painted and it'll have an anti-flip wing as I did on the old Maxx. Everything else is still up in the air, but I'll try for pics tomorrow.

And yeah, 1520 FTW!!!

redshift 08.05.2010 10:57 PM

Well admittedly I had some doubt as to the direct servo steering, and my concerns were not baseless. It survived 20+ runs before I snapped a horn, but not before doing some damage to the servo internals...

So a redesign is in progress, gonna be a few days at least. But this will be a permanent fix :yes:

What's_nitro? 08.06.2010 01:42 AM

http://jessenoller.com/wp-content/up...-awesome-2.jpg

Why aren't you working for DARPA? :lol:

Quote:

Originally Posted by redshift (Post 375806)
But this will be a permanent fix. :yes:

That's the best kind!

reno911 08.06.2010 01:58 PM

Nice build, can't wait to see the finished product.

Overdriven 08.07.2010 01:29 AM

I tried the Ofna savers once they are way too loose. The best I've been able to find is the stock MGT servo saver. They don't have much if any slop. If you don't want to integrate one somewhere else, I'd try them. Very nice work btw, can't wait to see more.

pinkpanda3310 08.07.2010 06:13 AM

Quote:

Originally Posted by What's_nitro? (Post 375812)
http://jessenoller.com/wp-content/up...-awesome-2.jpg

Why aren't you working for DARPA? :lol:

+1

Some really fresh idea's. Brilliant work Redshift :yes::intello:

redshift 08.07.2010 02:38 PM

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Quote:

Originally Posted by What's_nitro? (Post 375812)
Why aren't you working for DARPA?

They're a bit uptight....

Sorry for the delay guys, working on it atm, but your comments are much appreciated!

OverD, when I did the twin s.s. trials I was still running my old Maximizers with the 3/4" offset. So that made the pull on the knuckles much harder on accel & braking. I researched tire and wheel combos until I reached the conclusion to stick with what I had, only with new faceplates. The Zombie Max tires have over 2 years of use, are already taped, and I'm gonna use them up :)

I just needed to go back to zero offset on the faceplates, so I got my dimensions from the old faceplates. I decided I didn't want to mess with hexes, so they are slotted and I'm using screws instead of locknuts with these. Also I made the outer 4-40 screws countersunk to clean up the look. There's 8 or 9 hours in the wheels, time well spent IMO. I considered making some faux lugbolt holes in the center, I may make some changes to them. I'd like to hear opinions on that...

Comparison shot, and back side.

Bondonutz 08.07.2010 02:45 PM

They really look nice Jason, I can't see any dicision being the wrong one ?

Finnster 08.08.2010 12:12 AM

Man, nice stuff. Interesting setup. Wish I had access and skills like that. V cool.

pinkpanda3310 08.09.2010 07:43 PM

I was watching this again 'cause it's so good and came up with some questions redshift. How do you crank all for screws on the motor mount? 2 screws are behind the spur aren't they?

Are you worried about the threads stripping on the 1/8 aluminium? Or is there locknuts inside? I don't recall you saying what type of ali it is.

You've drilled a hole to access the rear cvd into the yoke but not the front, isn't that a bitch to get in? The front shocks also look like the stop the diff from sliding right out but that's no biggy.

Don't take this the wrong way, I love your build.:smile:

redshift 08.09.2010 09:46 PM

Thanks panda. I am scrambling to get the new steering parts designed and made, season is wasting!

The motor screws are indeed just accessible, I have a 16T pinion, any smaller and the spur would have to be removed.

I went out of my way to make most of the structural holes at least 1/2" deep. All the screws holding the joiner plates to the rear section are going through the tube wall into the motor mount and aft bearing block. So there is a minimum of 1/2" of thread there. The four holes for the front section are only tapped into the wall, for now. The plan was to use the same method with blind nuts and plastic locators, if I need. So far no issues there. As for material, this is a scrapbin build, so can't verify. None of it is soft however. There is zero flex anywhere in the chassis itself, it is for all intents and purposes, one piece.

The access hole on under the rear yoke was made before I realized I could get the centershaft and bearing block in place as an assembled unit. It'll be covered eventually, but it'll be useful for inspection or oiling.

Getting the front CVD in is as simple as slipping in the front chassis section between the plates. It needs to be held vertical at a little angle, but there's enough of a gap to see the end of it, so piece of cake!

The front shocks do impede removing the diff only slightly, same as on a stock Muggy or LST. The shocks can't be put on the rear side because the tierod is there. I don't anticipate needing to get the front diff out very often anyway. Chances are it'll be the rear that needs servicing more, and the shocks aren't in the way on the rear :)

Does require thinking 3 or 4 steps ahead to not "paint yourself into a corner" mechanically speaking, and on that account I think I've done pretty well so far. No CAD here, and no CNC. This is modern RC done oldschool.

Back to work for me.... ;)

pinkpanda3310 08.10.2010 08:45 AM

Quote:

Originally Posted by redshift (Post 376240)
Does require thinking 3 or 4 steps ahead to not "paint yourself into a corner" mechanically speaking, and on that account I think I've done pretty well so far. No CAD here, and no CNC. This is modern RC done oldschool.

That is oldschool! Custom parts do need a lot of forethought, I think that's 90% of the allure and 90% of the headache :lol:

simplechamp 08.10.2010 09:01 PM

Quote:

Originally Posted by redshift (Post 376240)
No CAD here, and no CNC. This is modern RC done oldschool.

Wow, I was already super impressed, but the fact that you do all the parts through manual milling and machining makes it even more amazing.

redshift 08.10.2010 09:37 PM

Well thanks champ :)

Everyone's good at something...

By far the hardest part of this project was making the blueprints. When I say blueprints I mean looseleaf paper, and index cards for the smaller items :mdr: But yes, lots of cranking on the mill too... And I have about 6 more hours on the lathe between last night and tonight, making progress. Many people don't appreciate the time and work that goes into the smallest most trivial-seeming parts, so it's nice when someone does.

If it advances the hobby in some small way, all the better :yes:

redshift 08.17.2010 08:19 PM

Steering has been conquered :)
 
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The direct servo thing was a neat little experiment, but alas, it was not to be. So I was not going to screw around this time...

Once I had some dimensions I made some bellcranks and lower bellcrank brackets. I couldn't decide on a bellcrank shaft setup I was happy with, so I decided to not use shafts. 4mm stainless cap screws were turned down to 6mm and shortened, and there are .020"/.5mm fiber washers to keep the bearings riding on the center race.

redshift 08.17.2010 08:25 PM

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I ended up with sort of a Muggy & LST hybrid steering. As with the direct servo setup, the lower bellcrank arm is about .4", or 10mm shorter than the Muggy bellcrank. The radius is .9". I forgot to do a comparo shot with the Muggy bells.

Goal #1 was making the draglink external (not passing through the tube) so that wouldn't hinder being able to seal up the tunnels and gears.

The upper bracket is .090 stainless. Bearings are now 6x12 vs. the Muggy's 6x10.

The Ofna servo savers proved inadequate without a draglink, but they will be more than enough now that they are linked.

JERRY2KONE 08.17.2010 08:44 PM

Wow
 
WOW Redshift I have seen your posts on here allot, but never really gotten to see the kind of work you do. This is an impressive project for sure. I love the direction you have chosen here and your work is quite good considering that you are using old school machining skills to get-er-done. Very nice work and clean look. It is nice to see someone go off the grid of using big manufacturing and come up with their own parts. That is the way this hobby started a long long time ago. Just guys sitting in their garage or basement coming up with ideas of their own and using stuff they had laying around to make incredible platforms. Cudos on your efforts Jason. I like others am impressed with your work. I look forward to seeing the project in its completed form.


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