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Not much gold left on this gold pan!

Posted: Mon Dec 02, 2013 11:40 pm
by Sixtysixdeuce
So, this was my first rear RC, bought with a lot of hard-earned lawn mowing/snow shoveling/pet sitting money back in '94 when I was 12. I ran it until the MSC burned up, then it got shelved. I got back into RC when I was 19, but I was into nitro then, so the old championship edition buggy continued to collect dust. I nearly got rid of it this past spring, but decided instead to bring it back to life with all new electronics and a fresh bearing kit to replace the original bushings.

Over the course of the summer and fall, it got upgrades here and there, but I decided to really hammer it out this last couple of months.

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It now sports RPM arms & rod ends all around, Losi mini-8eight stainless turnbuckles, 3mm graphite shock towers to hold the top ends of the FT B4 shocks. Motivation is provided by routing the 6,000 mAh 3S pack through an SC1200BL ESC to the Venom 3,300 KV can, which is geared 24/81, and goes out to universal axles after the stock stealth trans. B3 rear wheels with Jconcepts barcodes and Proline wide fronts with 4WD buggy Proline scrubs.

But the part I'm most proud of I just did tonight; the 4mm thick TQ style carbon fiber chassis, cut from a solid 250x400mm sheet:

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I use to run the pack at an angle in the stock tub, but the narrower chassis posed a problem with finding a home for the ESC, and with battery hold down. Solution? run a couple of HPI MT2 rear hinge pins up through the chassis, drill holes in them for pins, then use an inverted RC10 battery cup over the top and mount the ESC to that:

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Also had to move the steering servo forward as far as possible to clear a longitudinally mounted 3S pack. Had to notch and mill the nose plate a little, but it all worked out.

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So the true test of all this will be at the track, see if all the $$ and work has paid off. I'm not running nose braces for now, we'll see how it does. If I find the front flexing too much (or taco the nose plate), then I'll probably run carbon fiber round tubes for braces all the way back to the rear bulkhead, and tie them into the center of the chassis as well.

Re: Not much gold left on this gold pan!

Posted: Mon Dec 02, 2013 11:50 pm
by JK Racing
be mindful, you may need to run nose brace tubes into GT mounts.

Re: Not much gold left on this gold pan!

Posted: Wed Dec 04, 2013 3:15 am
by Sixtysixdeuce
be mindful, you may need to run nose brace tubes into GT mounts.
Like I said, if I find them necessary, I'll sort it out. A production graphite does not use them, though. Yes, the nose is incorporated into the chassis on a factory TQ, but regardless, this seems quite rigid. Remember, this is a 4mm thick piece of CF.

Re: Not much gold left on this gold pan!

Posted: Wed Dec 04, 2013 3:33 am
by clm
Wow, that is a thick chassis! Almost half as thick as the receiver!

You could do a similar chassis brace to the one on the rc10ds in another thread.

Chris

Re: Not much gold left on this gold pan!

Posted: Wed Dec 04, 2013 4:16 am
by kink
Even 3mm won't flex in normal use. 4mm is total overkill. I doubt nose tubes will be required. This is a world away from the wobbly alloy tub.

Re: Not much gold left on this gold pan!

Posted: Wed Dec 04, 2013 4:38 am
by clm
While the chassis is 4mm the nose plate is still stock thickness aluminum, the weak point will be in the z bend area where it laps onto the graphite I believe.

Chris

Re: Not much gold left on this gold pan!

Posted: Wed Dec 04, 2013 5:16 am
by Charlie don't surf
Clm is on point about the nose...especially with the track you run on! That configuration failed us on dirt oval BITD un-braced, it won't take more than a few laps & jumps to tweak, just a heads-up!

Re: Not much gold left on this gold pan!

Posted: Wed Dec 04, 2013 6:37 am
by RC104ever
Sweet ride! Can someone post another graphite chassis that has nose tubes? You guys are all mentioning this and I just can't picture how this could be done

Re: Not much gold left on this gold pan!

Posted: Wed Dec 04, 2013 7:04 am
by clm
RC104ever wrote:Sweet ride! Can someone post another graphite chassis that has nose tubes? You guys are all mentioning this and I just can't picture how this could be done
Take a look through this thread.
http://www.rc10talk.com/viewtopic.php?f=37&t=32182

Chris

Re: Not much gold left on this gold pan!

Posted: Wed Dec 04, 2013 10:21 am
by Sixtysixdeuce
Clm is on point about the nose...especially with the track you run on! That configuration failed us on dirt oval BITD un-braced, it won't take more than a few laps & jumps to tweak, just a heads-up!
Yeah........I don't really run this buggy on that track. It's so rough and loose that it's not even fun. This one is set up to run on the indoor clay track at MHOR.

I had originally intended to use GT nose brace mounts, but longitudinally mounting the 3S pack forced the servo all the way to the right, leaving no place to affix a brace mount on the passenger side. I think I'm gonna order up some CF round tube and mill some 7075-T6 GT-style braces that are a little shorter, and mount them about an inch and a half further back on the chassis. They'll be at a slight angle outward and downward, but it should work fine.

Re: Not much gold left on this gold pan!

Posted: Wed Dec 04, 2013 10:58 am
by jwscab
definitely run some kind of front brace: tubes, top plate, even tie rods, but you WILL bend that nose without support, one small whack on a rock or tumble and it's tweaked.

looks great! can you supply more information on the losi tie-rods you used?

Re: Not much gold left on this gold pan!

Posted: Wed Dec 04, 2013 10:18 pm
by Sixtysixdeuce
definitely run some kind of front brace: tubes, top plate, even tie rods, but you WILL bend that nose without support, one small whack on a rock or tumble and it's tweaked.
Well, I think I'm gonna mill a 2-into-1 offset brace from a piece of 6061-T651 I have, tie it into the chassis to the left of the steering servo. If this were a blue GT tub, I wouldn't sweat it, as I know how tough those are (only bent one, from a ~45 MPH crash into a truck tire), but I have zero experience running tub chassis without nose braces, so I'll defer to other's judgement on that one.

Re: Not much gold left on this gold pan!

Posted: Wed Dec 04, 2013 10:53 pm
by clm
What about machining a couple new servo mounts and tying the nose brace into the servo mounts so you don't need to drill additional holes?

Chris

Re: Not much gold left on this gold pan!

Posted: Wed Dec 04, 2013 11:06 pm
by Sixtysixdeuce
What about machining a couple new servo mounts and tying the nose brace into the servo mounts so you don't need to drill additional holes?
Would still have to drill more holes; I wouldn't want to count on a servo mount with a single screw taking the stress if I did hit something. As well, it could strain the servo, flexing the housing constantly. My experience says you don't want anything tweaking a servo if you can avoid it, as it doesn't seem to take much for those little (128 pitch?) pinion gears to strip-even metal ones.

The mount will resemble a half-pyramid in shape, attached to the chassis with either three 4-40 screws or two 6-32 screws, and the brace piece will be affixed to the mount with two 4-40 screws.

Re: Not much gold left on this gold pan!

Posted: Thu Dec 05, 2013 9:09 am
by Orange
You could use GT nose tube mounts that were made for the blue chassis. That only requires drilling a couple holes.. :)

**Edit** I just read what you said about the servo. LOL. If it were me I would just space the servo over a bit.