4wd Corr/Pro-4 Truck REDESIGN POSTED 12/23/09

[MetalMan]

It's a possiblity, but it wouldn't quite fit the Slash/Hardcorr bodies properly IMO.

Yeah, i guess you're wanting to use the narrow rims. I would too...

[Dagger Thrasher]

Sounds like this is gonna be a sweet project! Best of luck with it MetalMan, I'll be watching for sure. IFS with a solid rear axle is always very cool on scale trucks IMO. I'd cetainly go for a single purpose-built axle in the rear, for durability and realism over a more complex and possibly-fragile conversion of the Slash gearbox/suspension.

Incidentally, have you ever seen Thorbob's 4WD CORR-ish truck that he built a few years ago? It's an awesome truck that also used IFS and a solid rear, so you might find it useful: http://www.thorbob.com/baja_project_intro.htm.

[MetalMan]

I had seen Thorbob's custom baja truck, although I failed to remember about it until you reminded me . He's got more resources than I do, and apparently more motivation as well. His truck is of a different level than mine, as his probably weighs at least 16lbs. I'm shooting for ~6lbs with mine... Although I thank you for the link, it has definitely helped with some ideas.

so waht happened metal man? you still gunna do this project? really seems cool!

[MetalMan]

This project is still on, just been waiting for the time. Truckbasher's E-Revo outrunner project comes first, although I have put a lot of thought into the Corr truck while at work. For example, last Saturday while I was at work (the LHS) a customer came in, got some parts, pointed at one of the images of a CORR truck on a Slayer box, and said he had that truck outside.
It was Scott Douglas's truck, straight from being repaired after his recent bad crash.

The guy gave us a nice tour of it, so I got some pictures .

Front suspension/driveshaft:

Rear suspension:




The rear suspension was definitely the most interesting part of this truck to me . They designed it unlike other suspension setups out there, with parallel upper links mounted next to the shocks on the axle housing, and chassis-triangulated lower links. From what the technician guy said this suspension setup drastically reduces or eliminates the axle steer typical 4-link setups have when the axle articulates. And it's just as effective as a normal 4-link.

That does mean I will be trying to imitate this suspension design on my CORR truck project . Before I build it though, I will have to play around with the geometry.

oooh! thats nice! cool just glad to here that its still going! cant wait to see pictures of it.

[TruckBasher]

Thats one sweet truck...

Man, if you can copy that suspension then it will be one heck of a scaled CORR truck....

[tt-01 mamba]

Me thinks you need to look at this thread.

http://radiocontrolzone.com/showthread.php?t=167129

[TruckBasher]

Nice find but DaggerTrasher did post the main site of Thor Bob same project

http://www.thorbob.com/baja_project_intro.htm

[tt-01 mamba]

aw crp,
I really should read the entire thread.

[MetalMan]

Thorbob is definitely an inspiration for my truck, but his is nitro... Imagine if he'd made it electric.

[tt-01 mamba]

A company did make a copy of his design and made it electric.
It was nowhere near as good and died out.

[MetalMan]

Despite what it may look like, this project has been more alive than ever. I've been putting lots of time into it (too much!) just about every day, just wish the results were more indicative...

So far I have the MT2 front end built-up, the front (independent suspension) portion of the chassis is near completion, the upper deck for the front is being worked out, the Wheely King axle has been widened and has custom c-clamps to hold the shocks and upper/lower links, the link lengths have been determined, and I have come up with a viable suspension geometry (after much playing around with various mounting positions). Here are side views of the 4-link geometry:

Fully extended/uncompressed:


Compressed/maximum travel:


And a comparison of the two:


The rectangle to the left of the links represents the c-clamp, and where two lines cross that represents a hole on the c-clamp where something can be mounted. The very middle of that c-clamp is in line with the center of the axle. The most-vertical member is the shock.
When I came up with this geometry, I was trying to keep a good pinion angle, as this will be very important. Another important factor was the change in wheelbase that occurs as the suspension cycles. This geometry causes the wheelbase to change only 0.05" from fully extended to fully compressed. Overall wheel travel is about 2 inches.

This truck will use an outrunner in direct-drive-to-diff fashion, and is a KMS 2826-06 (730 kv), a cheaper version of the Axi 2826-12. I bought the Axi "Cooler" fan for the motor to potentially reduce temps. The ESC will be a MM (on its way to me from CC), and for batteries I will run 3s at the track for ~35mph top speed and 4s for about 45mph when this truck is in Slayer-killer mode .

[hoovhartid]

this project looks awesome!
looking forward to seeing more pics.

I have a question.



the parts circled in blue....how far apart are they in the 3rd dimension

not sure if the way I'm asking is making any sense....

what I mean is... I know they all cant be on top of each other, and im wondering if using different angles offsets the .05" you got out of the 2d geometry.
....just curious....I have never done a project like this and it got me thinking.

in any case. great looking idea!