Review Hobbywing Xerun AXE Crawling Combo

Hobbywing Xerun AXE Brushless crawling combo

By Tero Piispa

Why did I choose the AXE combo?

The Hobbywing AXE combo is my first brushless system from the scale crawler category. What I’ve liked about my Traxxas TRX-4 is the strong drivetrain and sturdy base, though at the same time the TRX-4 requires more power than the other scale crawlers from mainstream brands. The Hobbywing AXE would be perfect for this car, increasing drive time and providing a care-free, waterproof and high-performance brushless sensor system. I like that my trucks crawl accurately and are easy to control, and that they can maintain enough speed to overcome the toughest obstacles on the track. Using the system helps me create videos where the car’s behavior looks realistic. From what I understand, the brushless crawling systems by other brands such as Castle Creations and Holmes Hobbies are just as good, but since I have no experience from them, I’m not making a comparison here. Additionally, unlike the products of Hobbywing, the availability of the brushless crawling systems from the above-mentioned brands within the EU is quite poor. My previous experience from Hobbywing’s brushed Quicrun 1080 WP ESC, which has proved to have the best price-quality ratio for a crawling ESC at the moment, has convinced me that Hobbywing’s AXE might also be a good product and that Hobbywing is serious about establishing themselves in the scale crawling market.

Description

The AXE system is sold only as a combo including the motor and the ESC. Other brushless motors are incompatible with the system, including Hobbywing’s own brushless motors. There are three options for the motor for the AXE system: 1200 kV is the best choice if you want super slow crawling, 1800 kV for slightly faster crawling and 2300 kV, that was my choice, when you want to be able to drive both slowly and fast.

What’s new is the FOC (field-oriented control) motor and sensor system that reads the load on the truck taking into account the weight of the car, gearing and load produced by up and downhills. This makes the handling of your car easier and steering more accurate.

As a new feature the system also has an IP67 waterproof and dustproof rating. In addition, there’s an in-built wireless control option allowing you to control the ESC via an iOS/Android app using a Bluetooth connection. Hopefully the Bluetooth control becomes a standard in the better ESCs, and I personally believe that in the future they’ll become common in the cheaper ESCs as well. The AXE system seems to be available for 230–240 € or dollars around the world.

First impressions

The AXE combo comes packed in two stylish black boxes, the other one containing the motor, mine with a “2300 kV” sticker on it, and the other the ESC. The products are packed in clear plastic and are placed neatly in the boxes. Reminds me of unboxing high-quality consumer electronics. The motor comes with all the wires plugged in. The three wires going to the ESC are all black, about 10–15 cm long and clearly marked on the motor as A B and C.

Behind the motor wires there’s a round black male sensor wire. Because of the waterproofing, the sensor wire looks different from the usual.

The AXE ESC is bigger and heavier than the Hobbywing 1080 ESC. The package also contains a folded A4-sized manual, separate power wires with XT-60 battery connector and compatible heat-shrink tubing. And of course, the traditional Hobbywing stickers. You need to solder the power wires from the battery and the three wires from the motor to the ESC yourself. The black signal wire going to the receiver is fairly long. The power switch is in the usual Hobbywing style a red power button at the end of the wire with a programming button on top.

Mounting

The length of the sensor wire limits the ESC’s placement options on the chassis. In the TRX-4, the motor is located in the center slightly toward the front, and the ESC is well within the reach of the wires if placed in the center on the side of the chassis rail. If, due to lack of space, the mounting of the ESC is only possible far away from the motor, you need a sensor wire extension. For example, in the popular Axial Wraith the motor is mounted in the center of the car and many drivers want to mount the ESC in the front under the hood, so in this case, you’d probably need an extension wire.

The motor wires were easy to solder to the ESC with the motor mounted in the chassis while the ESC is in its chosen mounting spot. First, measure the wire so that it’s suitable length and cut off the extra.

When connecting the sensor wire, make sure that the connectors reach each other and that the lock ring lines up with the threading and tightens all the way up.

As usual, I soldered an extra JST connector to the power wires in case some new accessory needs power in the future.

The wire going to the receiver is all black. The connector has + and - markings to make correct connecting possible.

After connecting the wires, I calibrated the ESC to the transmitter. Step-by-step instructions can be found in the manual. When I tried to follow the instructions precisely, I didn’t manage to calibrate the ESC right away. I could finish the calibration successfully when I tried releasing the SET button immediately after turning the power on.

Tuning the AXE via Bluetooth

If you search the app store (iOS or Android) for Hobbywing, you can find a free app to tune and update the AXE. The first time you do this, select Bluetooth connection instead of a WiFi connection. Turn on Bluetooth on your mobile device and choose the correct device on the list of found devices. When you use the app for the first time, it requires you to enter a password which you can find in the manual. You can change it later in the settings. You can use different setting profiles and rename them. When you’re done with the settings, you can save them after which you need to turn off the transmitter and you can use the settings once the transmitter is powered up again. The settings that you can change are the usual ones available in Hobbywing’s programming cards. It has the same settings as the 1080 brushed ESC, and in addition, the motor’s running direction and timing parameters. The different settings are all made from preset steps, and you choose the ones you want. I was expecting to be able to adjust for example the throttle curve freely. In any case, I think it’s a good thing you only need a smart phone to adjust the settings and it only takes a couple of minutes. I hope this will be possible with all ESCs in the future.

The first test drives

Even though I had some idea how the FOC works, I was still positively baffled when I saw it in action. I have a huge rock on my yard that I’ve used with flagstones to create uphills for test drives. On the test track, I’ve been able to see the good and bad center of gravity of the car and see how the drag brake works.

The car felt soft to drive with default settings. Driving slowly was very easy. In steep, about 45° uphill the truck crawls just as slowly as you want and just as slowly as the gearing allows. Releasing throttle to neutral while downhill makes the car jerk only the amount that there’s play in the drivetrain. (Wheels-> drive axles-> universal joints -> transfer box -> gear box -> pinion/spur play = drivetrain). The drag brake can be adjusted to be softer, so the car doesn’t stop as if it hit a wall and flip over. I was positively surprised when I tested the TRX-4 crawling ability with second gear. With a precise throttle finger, you can drive as slowly with second gear as with a slow gear. I made a test video of this where I show this while holding a timer to prove that the video hasn’t been slowed down. There were lots of speculation around the first AXE videos about whether the video had been manipulated. The speed of the 2300 kV motor is very much like that of the TRX-4 with the default brushed motor and gearing. I was even a little surprised that the running speed wasn’t greater than that. Slow driving, the drag brake and the soft handling made a good impression on me. At the time of writing this article I’ve driven for about 10 hours with the AXE system, and I’ve managed adjust the settings to my liking.

The only thing I’ve not managed to adjust is fast and precise start throttle, so I’d have full throttle with no delays. This would be a good thing in crawling competitions where you avoid reversing and a small turning radius would help. With decent brushed crawling motors, you can exceed the turn radius on high-traction surfaces when you turn the wheels to the direction you want to go and pull the throttle sharply many times in a row, which will make the front of the car jump to the direction you want it to go. This is the kind of feature that I miss in this system.

I’ve already competed with a car equipped with AXE in two scale crawling competitions in Finland, in which the precise handling of the car is important. Thanks to the FOC feature, the handling of the car is easy in steep slopes. The drag brake that’s both soft and strong are a plus when driving uphill, where you sometimes have to stop the car. Narrow gates are also easier to pass very slowly and precisely.

The power efficiency, i.e. the drive time was one of the things where I expected improvement. The brushless motors always have a better power efficiency than brushed motors, so I expected the drive time to increase by half. I already noted last fall that a brushed TRX-4 with default motor empties the battery fast. About 2 hours of non-stop driving in the safari contest in King of Näkkimäki drained four 3S 2200 mAh Li-Po batteries. In comparison, two 3S 2200 mAh Li-Po batteries lasted for three hours on peaceful safari driving in the woods and cliffs with the brushless AXE system. I haven’t conducted more precise power efficiency and drive time research than this, but I can say that the drive time improved by at least one thirds. Crawling with slow gear on the TRX-4 you can achieve even longer drive time. However, keep in mind that there are several factors that affect battery life: the rolling resistance of the drivetrain, the weight and gearing of the car, heavy throttle finger, driving habits, temperature, etc.

Concluding remarks

I’ve understood that the Hobbywing AXE crawling combo is, due to the FOC feature, a different brushless system than its competitor system from Castle Creations. Apparently due to the FOC feature the kV numbers of the AXE motors are not directly corresponding to the kV numbers on the more traditional brushless motors. Now I also understand why other brushless motors are not compatible with the AXE’s ESC, it’s not only because they’re trying to make money but it’s a different system than the other brushless crawling systems. The best qualities of AXE, in my opinion, are the waterproofing, in-built Bluetooth and handling of the car when driving downhill. The FOC makes driving the car in tight spaces and slopes easier while maintaining a decent driving feel.

However, I can’t help wondering if Hobbywing AXE is worth its price. It is, if you are into scale crawling and do it a lot and often and if you have a high-quality truck with a durable drivetrain like Traxxas TRX-4or Axial Wraith, Bomber or SCX10.2. And if you want a water and dust proof system, speed and good slow driving features, and a reliable drag brake. The AXE system can be considered a good choice in the long run, when you upgrade your car but keep the AXE.

However, 200 € for a brushless crawling system is a lot of money and in fact too much for many hobbyists. Especially when you can get a high-quality brushed ESC (HW 1080) for about 100 € and a motor that allows you to go slow and have accurate steering, providing enough speed if you have short gearing in your car. Of course, finding top-quality crawling motors within the EU is difficult and the selection is not particularly good, and additional mailing and custom fees may be added to the price. I wouldn’t mount this system to a car cheaper than 200 € and smaller than 1:10. Also the 1200 kV and 1800 kV motor speeds make me wonder why anyone would get a brushless system that you can drive only slowly? Cars with two gears, sure, but you can drive slowly and have accurate steering with a comparatively cheaper brushed system.

In any case, I consider the Hobbywing Xerun AXE crawling combo a high-quality and successful system that is slightly different to its competitors. I enjoyed driving with it because slow driving is easy both uphill and downhill. I look forward to the 4-day Parker fest driving event in Italy in September, where I can drive with this system more than enough. RC scale crawling hobbyists are spoiled now more than ever, when something new and exciting is introduced in the markets every week. I’ve noticed that the competition between manufacturers is becoming tougher as the products are being developed faster and are becoming better.

Passionate RC scale crawling hobbyist and the creator of Bishop’s RC Crusade Youtube Channel

Tero Piispa