As I blogged about a couple of weeks ago here, recently I have become the owner of a Traxxas Revo 3.3 nitro powered RC truck. Over the course of the past couple of weeks, I have had the chance to break it in, break it out, and just plain break things, and although as a relative novice to the whole serious R/C car bit, I’m still getting used to the whole routine, I think I’ve had enough of a chance to get a feel for how it runs now. I’ve also had several opportunities to break out the tools to work on stuff, mostly as a result an occasional tendency for the thing to find its way into the nearest tree trunk at high speed (occasionally aided by the guy holding the transmitter, I suspect.)
The Revo 3.3 comes in what is referred to as a “Ready to Run” package, as opposed to the unassembled kits that some (not a lot these days actually) R/C cars and trucks come in. Basically what this means is that you could fuel it up and go, but in reality it means that you need a number of items before you can run it. First of all, you need nitro fuel (which, runs as much as $40 a gallon,) a fuel bottle to get the fuel into the truck (because for as much as nitro fuel costs you certainly don’t want to be spilling the stuff if you can help it,) a 7.2v battery for the starter, a charger for the battery, a glow plug igniter (because I found the Traxxas EZ-Start unit to be basically worthless for starting the plug, but it’s possible mine was broken out of the box)… Oh yeah, and 12 AA batteries for the transmitter and receiver. Pretty soon all this stuff adds up, but most of these are one-time expenses, and probably shouldn’t come as too much of a shock. The good news is that once you have the stuff you’re basically ready to go.
As soon as I got the thing running for the first time, I could immediately tell the thing was nothing like any of the other R/C cars I might have driven over the years. For one thing, getting the thing running for the first time actually proved to be a bit of an ordeal. Actually, I managed to get the thing going almost immediately, but the motor ran for about ten seconds, stalled out, and from there, it took another hour of trying with my Dad’s assistance (and replacement of the glow plug, which burned out almost immediately) before we could even get it fired up again. Even then, it took some leaning out of the carburetor before we could get the thing to not stall out at the slightest application of throttle. Once we got it going though, it was clear that this sucker was going to be fast. Even during the slow going of the first couple of break-in tanks of fuel at 1/4 and 1/2 throttle, it could run at a pretty decent pace. This made control a bit trickier than I had originally anticipated, which probably shouldn’t come as too much of a surprise given the low stance (for an R/C monster truck anyway) and wide wheelbase. At the very least, I did manage to avoid flipping the thing over until I was on the fourth tank.
Of course, the general rule for break-in on nitro powered R/C is to go slow early on, but Traxxas’ instructions for the last break-in tank (there are five total) are to run it up to full-throttle over three seconds, and keep it there for another two. This proved tricky without a lot of space, and somewhere along the line during this last tank I put it into a wall somewhere and managed to break the right front suspension A-arm and bend the pushrod which connects the wheel to the large single shock located inside the body of the truck via a set of rocker arms. Fortunately Traxxas provides detailed exploded views of everything, and once I began to figure out where things were and how to get them apart, the repair wasn’t too bad. Oh yeah, and somewhere along the line I managed to break the end off the transmitter antenna as well, just for good measure.
Once I finished the break stuff – er, I mean break-in period, a couple of days later I got a chance to go out with dad and Jared to try out the truck at Marymoor Park, where there are a couple of big piles of dirt out near the dog park that work well for R/C bashing. No longer being constrained by the break-in settings, it was now time to tune the engine for optimal performance. This, much like getting the engine started in the first place, was easier said than done. There are a number of different adjustments on the carburetor, and mostly I was trying to keep from running too lean, which would result in stalling if I let off the throttle. Eventually I got something that (mostly) worked, and got a chance to mess around some.
I don’t know exactly what it is, but there’s just something satisfying about kicking up a big cloud of dust, especially if you’ve got something that does it as well as this thing does. There aren’t a lot of chances to do jumps here (unless you want to go off the top of the big pile, which I did a couple of times) but I’m still getting used to things.
Unfortunately, this time around it was my Dad’s turn to break stuff, as his truck took a tumble and hit a rock in a bad spot, resulting in this busted fuel tank. Fortunately, one nice thing about these is that at least when cheap plastic parts break, they’re relatively cheap to replace. And break they will. Although I made it through this particular session with my Revo relatively unscathed, some running down in Bonney Lake on the Fourth of July resulted first in more trouble tuning, then some issues with the slipper clutch getting loose (and a burned finger while investigating the problem.) Once I got those out of the way (tuning is pretty much a constant thing when you’re running nitro trucks) I finally got it running well, just in time to put the thing into the nearest tree at high speed. Initially, the impact didn’t look like it had done much, but on closer inspection I found that I had managed to bend the pushrod on the front right corner again.
The good news with that was that I had another spare from the last repair job to replace it with. The bad news is that once I got the pushrod off, I found that it had been hiding a broken (but not quite broken enough to cause any failure which was obvious on initial inspection) CV shaft. Fortunately, the local hobby store has the stuff to fix this, and it’s not even all that expensive. Unfortunately, there’s also a clip that didn’t come with the replacement half shaft assembly that broke when I was taking it off, and they don’t stock the clips separately. Unless I want to try the other store up in Woodinville or shop online, it looks like I might have to buy a $10 kit full of parts I don’t need (right now anyway) to in order to get a 10-cent clip. Until then, the truck is sitting in pieces on one of the end tables in the living room, waiting for a ten cent part that’s probably going to cost considerably more than ten cents to come up with. I guess I shouldn’t be surprised by this, especially when my brother (the one who started the whole thing) said that the fact that you need to fix things when they break is a feature of the whole R/C experience. I actually do see his point and I don’t mind fixing things, but it might be kind of nice if I could at least come up with different things to fix every once in a while. I suppose it’s supposed to be a learning experience, although I suppose if I could just learn to stop running the thing into trees I wouldn’t have to be dealing with these things so much in the first place…