When Axial Racing introduced the Scorpion AX10 Rock Crawler last April the RC rock crawling world was turned upside down. Previously if you wanted to build a competition level crawler you usually needed to scrounge up parts from various other kits and build your own custom frame, but with the advent of the AX10 things have gotten much easier. All you need to do is build it, add your electronics and hit the rocks. However just like everything else in the R/C world, guys started dumping huge sums of cash into their AX10 to get that edge over the competition. The problem with that is we've taken a relatively low buck crawler and turned it into a big dollar money pit. That's the point of this build. We wanted to take a bone stock AX10, build it, add budget electronics, and document it's performance. Meet Project Scorpion!
Today we're going to look at what comes with the Scorpion rock crawler kit and what you'll need to get it up and running. Upon receiving the kit we rushed to open the box and were pleasantly surprised at how high quality the parts are on this truck. One of the beautiful things of the AX10 is the extensive use of anodized aluminum parts throughout. Everything from the beadlock rings, to the steering and suspension links, and even the chassis is aluminum. The chassis is anodized in black but most of the aluminum bits come anodized in a bright green. As much as we liked the green we really wish Axial would consider optional colors as well. How bad ass would an all mat black Scorpion be?
The Axial Ax10 Scorpion box
Like a kid on Christmas morning we couldn't wait to get it open! Here is the Ax10 box opened for the first time. When you first get it open you can easily see the body, wheels, and tires. The rest of the parts are buried under the body. Be prepared though, because the Axial Rock Lizard tires smell horrible. We could smell their stench before opening the box!
The Axial Rock Lizard tires. Nice soft sticky tires that smell like they just came out of the mold.
The box art is pretty cool but even the bag labels are decked out with some mean looking skulls.
Here are the various parts bags included in the AX10 kit. Everything is nicely labeled and easy to find.
Decals for the Axial B-17 Betty Body. Check out the gun rack for the rear window!
Axial B-17 Betty Body Decal Instructions. The strange thing about these instructions is that they suggest you drill holes in the top of the body for body mounts. However the Axial uses side mounts! :0
A nice addition to the Axial kit was the supplied thread lock. Most of the screws on the AX10 are screwed into nylon locknuts where thread lock isn't needed. However it is imperative that you use this stuff on metal to metal parts such as the tiny grub screws holding the drive shafts in place.
The Axial AX10 Scorpion Owners Manual. It's simple but very well written.
The Scorpion's axle cases still on the parts tree! I can't believe we were able to keep ourselves from cutting them off yet.
The AX10 wheels. The wheels themselves are made of some sort of composite plastic, but the bead lock rings included are aluminum.
The unpainted lexan B-17 Betty body. Thankfully it includes window masks and protective covering.
Some of the beautiful aluminum parts included. From left to right are the inside beadlock rings, outside beadlock rings, and the steering/suspension links.
Alright, now you've got a good idea what is included with the Axial but you may be wondering what else is needed to complete the kit. For that you'll need a 2 channel radio system with one servo, an electronic speed control, and a motor.
It's funny how such a simple thing can make a big difference. Years ago when people needed a motor with torque for their RC truck they had two choices, either a 27t stock motor, or a big dollar pulling motor. The 27t motors were cheap but they just didn't have enough torque for rock crawling. The pulling motors (ie. Astroflight Pullmaster) had a ton of power but were expensive, required an expensive ESC and took up a lot of real estate on the chassis/axle. Finally one day somebody had the bright idea to throw motor intended for a motor lathe in their truck and the rest is history. The lathe motor has truly changed the face of the r/c rock crawling world. Considering how cheap these things are we knew it was the perfect choice for Project Scorpion. Currently these motors are available from 35t all of the way up to 85t. We originally chose to go with the tried and true 55t but because they were on backorder we decided on the Integy 45t Pro Lathe Motor. ($19) This motor has really good torque and with the gearing in the Axial it's pretty much unstoppable. I can't even imagine what the 85t would be like.
For the ESC we were again looking for something to meet a very low budget. During our search we found a few models that seemed to fit our purposes but then a search on a rock crawling forum pointed me to this one. What caught my eye with the LRP Runner Series ESCs is that they are totally waterproof! In the past I was forced to wrap my ESC in a ballon to keep moisture out but in doing so I took the chance that it may overheat due to a lack of airflow. With this ESC that is no longer a problem. Hopefully other ESC manufacturers will follow in LRP's footsteps, we need more waterproof ESCs. The exact model we chose was the LRP Quantum Runner Reverse. ($40) It is only rated for 18+ turn motors but considering that this thing will only be used in a rock crawler I don't see that ever being a problem. There are two drawbacks to this ESC however. First off the reverse delay. For fooling around on the rocks in my backyard it doesn't bother me all that much, but to some it may be annoying at the least. Secondly the automatic setup. This ESC has a completely automatic setup. Just plug the battery in and go. The problem is that the ESC has the knack of sometimes reversing the throttle. This little annoyance is a known flaw with this ESC and really isn't a big deal. If it does reverse your throttle all that is required to fix the problem is to disconnect the battery for a second.
Here is a size comparison of the Quantum Runner Reverse vs our old school receiver. I had no idea this thing was so small.
A close up picture of the ESC
Here is what comes with the Quantum Runner Reverse. A bunch of decals, capacitors, and of course an owners manual. (not pictured) It is highly recommended you install the capacitors to your motor to reduce glitching.
Here is the ESC after we installed a set of Deans connectors.
The Quantum Runner Reverse includes a heatsink to fit over the FETs. However it is imperative that when you install the heatsink you use the tiny rubber grommet which is included. (arrow) Not only does this grommet keep the heatsink secured to the ESC but it also stops the heatsink from touching the FETs. If the heatsink or any other metal object were to touch any two FETs at one time it would result in the shorting out of the ESC.
For the radio we chose a simple Futaba PH2 AM radio system. ($42) I've been using these things on RC cars and trucks for years without a hiccup. It includes one standard servo.
I've always felt that the best part of the RC hobby was in the build. Sure I've bought ready to run models before but it's just never the same. There's just something about staying up to the wee hours of the morning building a kit that really makes this hobby special. It's finally that time, time to build our
Axial Scorpion project truck! Building the Axial Scorpion is quite easy. There are some things to watch out for along the way but overall it's a quick and easy build. Follow along as we build our Axial Scorpion and we'll give you some pointers when we can. The first part of building the Axial AX10 is the axles. The Scorpion's axles are molded of plastic and contain metal gears. As with any true rock crawler there are no differentials, instead there is are included lockers. What is surprising is that Axial went through the trouble of anodizing the aluminum lockers which will never be seen once installed. Building the axles is very straight forward. Something to look out for though is that you need to be sure to press the pinion gear and the bearing it rides on well into the axle. If you don't push it in far enough the pinion will stick too far into the case resulting in too tight of a gear mesh causing premature wear. After assembly try turning the axles and if they roll smoothly all is good. Be sure to follow the included instruction update!
Here is a picture of the ring and pinion gears before going into the axle
The ring gear with the anodized aluminum locker. Although we haven't had any problems with the locker in our truck Axial has release a sintered metal upgrade locker. Notice that this truck doesn't have a differential. Where we're going, we don't need no stinking diff!
Here is the locker built with the axles and bearings installed.
The axle case with the gears installed
The completed axles. I can only imagine how many other projects people will use these things in in the future. Although they aren't completely scale in appearance they are very well built and would work fine numerous scale projects.
Here are the completed suspension links. The Axial AX10 uses a three link setup that gets roughly 70 degree of articulation. Overall they were very easy to assemble. Just keep on an eye on the direction you install the ball ends.
The completed Axial driveshafts. We have found these to be a weak link in the drivetrain. (more on that later) Be sure to use the included thread lock on the setscrews that hold the drive shafts to the axles/transmission otherwise they'll come loose in minutes.
The shocks on the AX10 are made of plastic. They include a spacer that Axial instructs you to install on the lower part of the shock shaft. However it's a very common mod to install the spacer on the shaft before installing it in the shock body. The result is a lower center of gravity. Here we are filling the shock with the supplied 30wt fluid. Just fill it almost completely and then slowly move the shaft in and out to remove any air bubbles that are in there. Once you've got the air out, fill it up the rest of the way and install the cap. When installed the ball ends on the end of the shaft be very careful not to scratch or nick the shaft. We found that putting a heavy towel around the shaft and holding it with a pair pliers worked best. Just be sure the pliers aren't scratching the shaft!
Here are the completed axle assemblies with the shocks and suspension links installed. The most time consuming part so far was assembling the shocks.
Here are the assembled beadlocks with Axial Rock Lizard tires installed. These took us the better of three hours to assemble!!! My fingers were completely raw afterwards. It is suggested that you get yourself a good set of allen/hex drivers and wear gloves. You may want to watch
this video on youtube for a better idea of how to assemble these. BTW get ready for a skunk in your house. When the Axial arrived at our doorstep we smelled a funky odor coming from the box. With further inspection we found that it was the tires that smelled so bad.
We assembled our beadlocks with the supplied uncut supplied foams. However you can cut the foam inserts for more tire flex. Another common modification is to fill the tire will BBs or stick on lead weights. The result is a heavier front end which increases traction and improves climbing ability. We may try one of these mods in the future, though the thought of taking the beadlocks back apart doesn't sound too appealing.
The next item that needs to be assembled is the truck's transmission. It's a very quick and simple assembly. Be sure to use threadlock and grease where the owners manual suggests. However be careful not to install too much grease as it will add unneeded friction to the drivetrain.
Here are the electronics on the radio tray. The electronics are attached to the bottom side of the radio/battery tray with the supplied servo tape. I suggest you check and double check the fit before you tape them in place because it's a tight fit. After this picture was taken we wrapped our receiver in a balloon to make it waterproof. Our Quantum Runner Reverse ESC is already waterproof. The Axial is a blast to run in the snow!
And just like that the Axial AX10 Scorpion chassis is ready to rock and roll. I believe it took a good eight hours of assembly to get to this point but that includes taking photos and the horror of assembling the bead locks.
The obligatory articulation shot or two!
The Integy 45t pro lathe motor installed.
The front steering setup. We installed the standard Futaba servo included with our radio. It has plastic gears which have been OK so far. However if you want to be on the safe side you might want to either go with a metal gear servo or install one of the supplied servo savers. With this setup you place your battery pack on the radio/battery tray but Axial also sells a mount that allows you to lower the truck's center of gravity by placing your battery on the front axle. It's definitely something you'll want to look into if you're into competitive rock crawling. For our purposes this setup works fine.
The rear axle setup. We used the supplied steering lockouts for our truck, but with Axial's rear steer kit you can easily make your truck 4ws.
The truck fully assembled less body.
After spending nearly eight hours building this rig and another couple painting and trimming the body it's finally time to take her for a spin. We originally meant to take our project truck out on the rocks to do what it was intended for, however a large snow/ice storm hit our area a few days before it's maiden voyage so we were limited to testing it in those conditions. Fear not! We were still able to break something. We were really bummed that we couldn't get Project Scorpion on a nice big mountain of dry rock. However in the end we found that the icy terrain proved to be more than sufficient to show what the Axial could do. We tried throwing everything at the AX10 to see what we could and couldn't break and at the end of the day only one part was proven to be a weak link.
If you've been around the RC rock crawling world for any amount of time I'm sure you've already heard that the Axial's driveshaft is it's weak link. We did too. To be honest we always thought it must have been driver error, but after just one battery pack we found ourselves in the same situation other enthusiasts have many times before....our drive shaft broke. We had heard that a common problem with the AX10's driveshaft is that the yokes would pop out of the drive shaft, but in our case one of the little ears on the driveshaft split. I'm sure you're thinking we did something stupid to blow the drive shaft like that but in reality is was just a matter of a lot of torque, and a wheel that got slightly hung up. I was personally very surprised at how easily that thing broke. A common solution, and the one we chose to go with, was to swap in a set of Traxxas Stampede half shafts. The Stampede's half shafts are slightly shorter but are a direct fit with the Axial. After numerous successive battery packs we have yet to break these.
As for the durability of the rest of the AX10 Scorpion we have yet to find another weak link. During testing we did "lose" the driveshafts a few times but it was merely due to our stupidity; we forgot to put threadlock on the set screws.
In the past we have had the chance to drive a few other home made rock crawlers that performed well but weren't anything to write home about. The Axial on the other hand is awesome! We were shocked at how well it performed out of the box and even more happy after performing a few tweaks. Even using the stock battery location it was found to have a very low center of gravity and it took getting the truck nearly vertical for it to roll backwards. Like all live axle trucks the Axial does exhibit a good amount of torque roll. We found that by adding a shock spacer to the left rear shock it was reduced but it's unlikely you'll ever get rid of it completely. The Axial is very well balanced, actually too well balanced for rock crawling which works best with a front weight bias. All in all we were very happy with our purchase and plan to keep you up to date on future mods and breakages as they happen.
As for the electronics, they performed flawlessly. We originally mounted the antenna inside the truck zip tied to the chassis. However the reception with that setup was so bad that we went back to using the stock antenna mount. As you can see from the photos we ran the Scorpion through ice and snow and thanks to our waterproof ESC (and balloon wrapped receiver) we didn't have one hiccup. Even the cheap plastic geared servo that came with our radio system has held up fine...without a servo saver!!! The Integy 45t Lathe motor has proven to be more than powerful enough for our needs. There wasn't one time throughout our testing that it stalled. I really can't see why anyone would need anything more powerful, though a higher turn motor may be smoother at lower throttle settings.
Here is what our driveshaft looked like after it grenaded. As you can see one of the ears split straight down the middle.
Here is Project Scorpion transversing a slight incline on a complete sheet of ice. We were stunned at how well it climbed even on the most slippery of surfaces.
Yes, even the Axial can get stuck if the snow is soft enough...LOL
The Axial was very well balanced and could go nearly vertical without rolling over backwards.
A few articulation shots
We ran the Scorpion over everything we could find. From ice and snow, to branches, logs, tree stumps, and even rocks. (go figure) On the night of assembly we even built a big stack of boxes in our workshop to see what it could do. It climbs very well.
Is this the end? Not by a long shot. Even though the Axial Scorpion performed well out of the box we noticed that a
few cheap mods greatly improved its performance. In the coming weeks/months/years/millenia we plan to keep you up to date on those mods and anything else that breaks along the way. Thanks for following along on the build.
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