FLM SPV2 Hard Case - Hard Tail Crawler - Wheelie King

[stampedeproject]

FLM SPV2 Hard Case
Custom Hard Tail Crawler
By Tony Arnold - StampedeProject.com Yet another "what the hell can I build with crap I have laying around project". After many years, I have seemed to amassed a huge pile of parts that could make some very cool RC's with a little creativity and effort.
In this case I scrounged around the corners of my basement and garage and ended up with enough parts to net a $0 cost build and something truly unique and in this case a Hard Tail crawler. I really haven't seen many hard tail crawlers out there... in fact I don't recall seeing any.
Functionally I'll have to wait and see how it performs, but from an "in theory" perspective, it's a sound idea. No rear shocks, therefore no chassis torque twist and with the LOOOONNG Wheelie King shocks up front in full droop, I still get about a wheel height's of articulation which is about perfect.

Here is the parts list:
HPI Wheely King Axles and Front Shocks
RCP High Clearance Knuckles with CVDs
EMaxx/Revo Pushrods for Steering and Rear Lock out Links
FLM Extended Stampede Black Link as the Servo Steering Link
RC-Guy.com Servo Mount
Tower Hobbies MG Servo
FLM SPV2 Chassis with the nose bent inward to meet with a FLM SPV2 55mm spacer
Axial Front Aluminum Links, plastic Upper Links, Driveshafts, and Transmission Plate
Axial Links for rear lock out
Axial Rear Red Billet Links
Heavily modified Traxxas Stampede Trasmission with locked Diff
Proline Beadlocks and M3 Masher 2000 Tires
M'Troniks ECO20 - FYI this ESC sucks!
Axiom 85T motor
Kyosho RX
Scrape Lexan for all the body panels prayed black with Scotch Extreme Duct Tape Applied on the exterior.
I do need to shorten the front links since I am measuring in at 13".





In a more perfect world I would have used an Axial Transmission as well, because it's more compact and already locked. The M'Troniks ESC is one of the worst pieces of crap I have used. My experience with M'Troniks has been disappointing before, but this piece of garbage confirms that M'Troniks ESCs are just junk. A Tekin FXR or Castle Sidewinder or even a stock Axial ESC would be better choices, but then again, I didn't have one to spare for this project. Still trying to figure out how I ended up with two extra HPI Wheely King Shocks.

[Karadjas]

It looks nice, but I'd be a bit worried about it falling over when the rear is more vertical. On a sprung/droop/torsion (suspensioned?) chassis, when the rear axle is at a 30* angle to the front, the chassis is about halfway from either. In this, when the rear axle is 30* over, so is the chassis and all the weight on it. So if your rear axle is on a sidehill and your front is on horizontal ground, the chassis will still be fully sideways. Like picture 4 in your post.

The theory makes sense in my head, go outside and prove me wrong

[stampedeproject]

Originally Posted by Karadjas

It looks nice, but I'd be a bit worried about it falling over when the rear is more vertical. On a sprung/droop/torsion (suspensioned?) chassis, when the rear axle is at a 30* angle to the front, the chassis is about halfway from either. In this, when the rear axle is 30* over, so is the chassis and all the weight on it. So if your rear axle is on a sidehill and your front is on horizontal ground, the chassis will still be fully sideways. Like picture 4 in your post.

The theory makes sense in my head, go outside and prove me wrong

As with most crawlers though most of the weight in in the front... On the direct approach and sidehill incline board test, it seemed to perform as well as my other comp crawlers.

Yeah need to get outside, but the wife and I are getting ready to go out tonight, so no go today.

[Karadjas]

the motor/tranny/thick alu TVPs are on the chassis though. So it'll be your front axle battling everything else.

On consistent sidehilling, like a flat platform tilted over, it shouldn't make any difference. The way I see it, when the front axle steps off that platform, the chassis will still be at the same angle as the platorm, instead of half that.

[stampedeproject]

Originally Posted by Karadjas

the motor/tranny/thick alu TVPs are on the chassis though. So it'll be your front axle battling everything else.

On consistent sidehilling, like a flat platform tilted over, it shouldn't make any difference. The way I see it, when the front axle steps off that platform, the chassis will still be at the same angle as the platform, instead of half that.

The theoretical upside is that you are not upsetting the rest of the chassis when the front steps off. Only the front articulates so you CG doesn't change as much. I have been in a lot of situations where the rear suspension of my rig was the rolled over culprit (cough Midwest Challenge).

OK my wife is still upstairs "getting ready" so I took about 15 minutes to get this thing on the rocks.

I gotta say I am impressed it does seem very stable. You do need the long Wheelie King length shocks to get the usable articulation, but I think folks should give this a try - for one thing I have zero torque twist. Even pulled a couple lines that only my Slingshot and SPV2 comp chassis can run. That may be in part due to the extra 1/2 wheelbase, but still pretty impressive results regardless

For what it's worth I think most of us probably all have a few WK shocks laying around to give it a try. Mine were droop sprung with springs under the pistons and 90Wt oil... uhhh I think??

Other events during that 15 minutes were realizing the Silly Putty didn't quite lock the diff, however it seemed to work advantageously in SOME cases where for example Clod Stall would be a good thing. I LOATH the M'Troniks ECO 20 ESC. This thing has NO power at all and stalls at the slightest little freaking bind. I am sensing an ECO 20 on ebay soon.

Definitely and idea worth exploring further for fun.

[stampedeproject]

Still lessen with this thing and continue to be impressed. I'll bring it to the NSCA summer series on June 20th and see what the masses think.