Project SR-71: A Stealth R1 Build

[derb]

Chassis:
GMade R1
Custom Carbon Fibre chassis with Stealth chassis skid plate
Junfac 3x LED lightbar
Junfac chrome diff covers

Axle/Steering [Front & Rear]:
Savox SW1210SG Waterproof Digital Servos
Junfac alloy 7degree c-hubs
Junfac alloy knuckles
Junfac CVD kits
Junfac heavy duty steering links
Junfac low CG servo & battery plates

Suspension:
Traxxas Big Bores, Mini-T Springs
Custom bent alloy lower links
Junfac adjustable upper link mounts
Junfac adjustable lower link mounts

Wheels/Tyres:
Vanquish SLW V5 Respun 2.2" wheels [vented]
ProLine Super Swamper tyres in G8 compound
Crawler Innovations Double Deuce foams, soft fronts/medium rears
70g weighted front wheels

Drivetrain:
Axial 27t brushed motor, 12t factory pinion
JunFac carbon steel driveshafts

Electronics:
Holmes Hobbies BR-XL ESC, waterproof version
Castle 10A BEC @ 7.4v [plasti-dipped]
PunkRC Dual Steer Computer [plasti-dipped]
FlySky GT3B transmitter & GR3C 3-channel receiver
HobbyKing 850mah 3s batteries x6 [plasti-dipped]

[derb]

This is my second crawler after owning a Tamiya CC-01 for about 6 months now. I'm very new to the RC game, and I love the CC-01 dearly, but I wanted something that could handle a lot tougher terrain and easily keep up with my mate's SCX10.

I've has the R1 on my radar for a while, but as soon as I saw the Stealth chassis kit, I knew I had to have it and that pretty much decided my theme for me. I've done some of the standard hop-ups like the bent links, chrome diff covers and JunFac axles. And after a lot of reading I started with a 55t motor, vented the stock beadlocks while adding 70g weights to the fronts, and configured the suspension as droop front, sprung rear. Then I set the BR-XL to 70% drag on the Holmes Hold setting, maxed the BEC and set the LiPo cutoff and that's it in terms of electronics.

Then it was onto some looks with added functionality. The servo was sky blue and the batteries a darker blue, which obviously didn't fit the theme, so I used Plastidip to coat the servo and batteries with a thin, but durable and waterproof black coating. The servo was already a waterproof Hitec unit, but the batteries didn't look that watertight so I dipped them and now I can go into nice deep mud/water. I would definitely require this ability because...

Today was the first real run and wouldn't you know it, it's been raining off and on for the last day or so here. But that didn't stop me, or the R1 that much. My local playground is made up a lot of loose clay hills dumped by an excavator, and a bunch of jagged rocks with minimal surface grip. And water, oh the lovely fun puddles. The tyres quickly became more mud than rubber, but these stock tyres aren't too bad on my dirt/mud/clay. Not sure what some of the other R1 owners were talking about.

But I did find out a few things that need looking at. The cheap RC4WD motor was a touch too slow in the wheel speed department and started to just give up at points needing torque due to all the added mass of mud. Also, the steering angle was terrible. I cranked it as far as my endpoints and the physical limitations of the chassis would allow, but the turning circle was huge. Servo did a pretty good job, again counting for the extra mud weight. Clearance and articulation were awesome though. I like the BR-XL too, I'll drop the drag back to 50% and probably tune the throttle curve for a little less punch. I'm sure it's not real good in terms of pro rigs or something, but it breezed over some pretty crazy stuff today.

Initial verdict, very bloody happy! Loving this rig even with the issues listed above. Cant wait to try it on some rocks. I've got a set of Vanquish 2.2" wheels coming in and I'll track down a set of 2.2" Super Swampers in G8 compound. My mate ran them in 1.9" today and they were amazing. Then I'll be doing the Wheely King CVD and knuckle conversion for more angle. And I need a nice 45t motor somewhere in there too, phew. I've also got some Gear Science gel coming in and sealed Avid bearings, so I'll rebuild the gearbox and axles over Christmas. Lots to do and lots of pics to come.

[Modbug]

The stealth chassis is definitely one of the coolest looking designs.
Looks like your having fun, good times.

[derb]

Thanks man, I need to get some new pics up. I've put on a new set of Vanquish rims and Super Swampers. I also bent the stock long steering rod to get some more clearance around that front diff cover. And then I tried to run it in the local sportsman comp class and promptly dropped it on it head about 10 times before I bowed out. Damn canopy is scratched to hell and bent down a little. :(

[bikerzee24]

Good looking stealth chassis, I wishing I just kept my chassis bare like yours instead of putting body panels on it. Either way people have something good to say about it when they see it.

[derb]

Thanks, I'm planning to put some carbon fibre covers on the top bits for looks and to protect the electronics tray in the front when it rolls.

[bikerzee24]

Nice man, well don't forget to take some pictures when you have it all done and share them.

[pokeyYJ]

Looks great!

[highwaystar]

Very nice write up. I had a few questions about this rig, but you took care of them.

That mud looks fun!

[derb]

It wasn't as fun as I'd hoped, it was more like glue. I had a good inch or two on the soles of my shoes and my mate killed a servo from all the extra weight on the front wheels. I'm going crawling again this weekend so will get some up to date pics of the new wheels/tyres and a few other bits like the CF panels I want to do. Thanks for the replies guys, I thought it was a bit of a ghost town in here at times.

[bikerzee24]

Yeah I agree with you, there are times where I don't touch any of my RC's but when I do, I have a brother in law to go to, but sometimes he is not as helpful as some would think. I joined this week and been trying to make conversation with some of the threads here it yeah it has seemed like a ghost town. I'm a picture guy so I like to see detailed pix of peoples rigs and the set ups such as where they mount thier shocks and tires and wheels, and not just a listing of them. I have gone a long way by searching youtube for fix-it an such, but these forums help out a lot when someone is barely getting into crawling or doesn't do well with thinking outside the box.

[derb]

I'm a fan of pic dumps too, my CC-01 thread is packed with pics. I've not neglected the R1, it's just that I never remember to take pics when I'm just having fun and mucking about. Plus it got so scratched up and somewhat dented at the last comp I was kind of embarrassed about it. I'll throw up some pics tonight to satisfy our visual urges and then take some proper pics at Cedar Creek on Sunday.

[bikerzee24]

That sounds good, and yeah I know what you mean about the pictures. Some may think its wierd that people take pix of their rc cars, but shit it help more than one person on how they would like to set there stuff up. I always forget too, to take pictures while I am playing, and get pissed off after I am done for not taking any!...

[derb]

Since the last update I have bought a set of Vanquish SLW V5 Respun 2.2" wheels that came with sweet red beadlocks and screws that really match the colour scheme. I pulled apart the stock wheels and tyres and put the 70g of weights in the new front wheels, then bought a set of 2.2" ProLine Super Swampers in the G8 compound with the standard memory foams for now. I was really torn between a set of trail-like tyres like the Swampers, or a set of proper rock tyres like the ProLine Chisels, but ended up going with the Swampers after seeing my mate's 1.9" set get crazy traction on every surface.

Then I moved the inboard lower suspension link points onto the skid plate rather than the body for a little more articulation. I also noticed the steering linkage was hitting the pumpkin on full lock and limiting my steering angle, so my mate threw the long link into his vice and gave it a little persuasion. Now it clears the pumpkin by miles and gives me a little extra lock. It has barely affected the front toe in, but I will throw a couple of spacers on the ends to zero out the toe again.

I also installed a Castle 10A BEC to pump the full 7.4V into my servo. Now the response is much quicker lock to lock and it's strong enough to 'walk' the front sideways by turning lock to lock on slopes. My mate also shortened and tidied up my wiring a bit, but I've still got to shorten the servo lead. I've also bought a y-connector so I can run the servo and its BEC off a single channel input. This will also allow me to plastidip the entire receiver for total water proofing, along with the BEC which is just covered in electrical tape at the moment.

Then I took it to a comp and tried to run the Sportsman class. Lets just say I was rather embarrassed as it DNFed on the first gate of the first course! I just kept falling end over end and scratched it to hell, and then managed to put a decent dent into the top of the stealth chassis. So much for super strong. It was just way too top heavy and didn't droop enough. I knew when I bought it that it was meant as a competitor for a Wraith, not as a true sportsman rig, but I still thought it would do better than it did.

New plan? Thought you'd never ask. Disassemble the entire chassis and drill more shock mount holes to allow the rig to droop and articulate even more. I also got my sealed bearings from Avid and a tube of Gear Science RC gear gel. I'll rebuild both axles and the transmission with the new bearings and gear gel which should make all moving parts pretty water resistant. Not water proof, just enough to let me submerge it once or twice and not have to totally rebuild it every time. Can you tell I like water? Yeh, I really like water.

I'm still milling over the idea of making templates and getting the stealth chassis made of carbon fibre. The sides are easy as pie, but the canopy part would be a nightmare to try and create. I do, however, have some thin CF sheet that I plan on putting to use. I screwed up when ordering and mistook 0.3mm for 0.3cm, so I got a paper thin sheet when I was expecting something more like a book cover thickness. Anyway, I'll use what I got sent and put some covers over the front and rear ends for looks and also to help protect the electronics tray up front a little bit. I may line the inside of the sides with it from behind so all the open gaps will show CF.

If you've stayed with me this long, many thanks for actually reading. ANYWAY, time for a massive pic dump!

[paleblue46]

Sweet looking rig you have there

[bikerzee24]

Damn those wheels looks sick...loving it man.

[derb]

Thanks guys, your enthusiasm is helping me get back into the swing of the R1 after the miserable comp performance.

[bikerzee24]

hey no problem, it's a fun crawler with so many options

[derb]

I put two carbon fibre panels on last night and went out to Cedar Creek with my mate. Starting to love the R1 again. It looks great when its articulating and gets over almost everything. Also took it for a decent swim and it didn't miss a beat, I love water so much!

[paleblue46]

carbon panels look good on there . dont get down about a rough comp we all have bad days