Portability Oscillation could be better
Long battery life
Price: $550 (base model); $675 Grand Slam Pack (tested)
There’s arguably no better social distancing practice partner than a ball machine. True, you don’t get the live ball benefits—not to mention the trash talk or post-workout adult beverage—that come with trading shots with a flesh-and-bone adversary. But in terms of never missing a shot, getting tired or smirking at a flubbed volley, you can’t beat the dependability of a ball machine.
The brand-new Slinger Bag puts an innovative spin on this familiar teaching staple. A ball launcher constructed for maximum portability, it has a straightforward, user-friendly design that allows players to hit the courts and get right to work on their games, whether it be soft feeds for beginners, or spin-laden drives for the advanced set.
From the tough nylon covering, to the rugged zippers, the Slinger Bag reminded me of a duffel bag on steroids. There are three main compartments: a deep pocket on top for racquets and gear, a hopper cover that extends out to house balls, and bottom panel that reveals the launcher, speed controls and battery unit. There are several other zippered accessory pockets for personal items, USB chord for phone charging, and launching angle adjustment bar. The zippers are quite hearty, which gives the sense of durability, but they can sometimes be stubborn to move.
A clip and Velcro strap help hold an optional telescopic ball pick-up tube. When extended it can carry around 20 balls and makes gathering them up more convenient. However, I ran into a few problems with mine. One of the plastic casings that keeps the tube locked when extended needed to be re-glued several times. And when filled, the balls don’t slide easily through the tube, making it more difficult than it should be to put them back in the hopper. There always seemed to be a ball or two getting stuck and I had to shake the tube rather violently to jar it loose. I actually reached out to Slinger and they assured me that these were initial production run problems, and have subsequently been corrected.
The bag is a bit bulky, but should fit comfortably into most car trunks—two carry straps are attached to assist in completing the assignment or do any general lifting when needed. Extendable handles and luggage wheels provide the transport. The carry straps do awkwardly fit over the shoulders, and were initially thought to be a possible option, but it's not recommended. I tried it and the closest comparison I have ever experienced was the cumbersome backpack I lugged across Europe after college.
Setting up the launching process is supremely uncomplicated. Position it on the court, set the speed of ball and rapidity of feed with the turn of two knobs and turn on the power. A button on the supplied remote control will get the machine started—one beep indicates it’s working; a second beep just before balls start slinging. The internal hopper will hold a case of balls when closed; twice that amount when completely open. When the balls are fresh, there can be a noticeable build-up of felt around the launch and control panel. A few blasts from a can of compressed air between each session would be wise.
The bag shoots straight feeds that can come upwards of 45 mph and between 2-to-10 seconds in frequency. More impressive than the speed of the ball is the amount of work on it—as you increase the pace, the spin level goes with it. At top level the incoming ball bounds like Rafa's forehand. Depending on the angle of the chute, you can get great practice handling those dreaded shoulder-high backhands.
The whirring sound the launcher makes fluctuates depending on how aggressive the speed and feed. In one session, some debris got loose around the motor and it sounded like a swarm of murder hornets. Generally, though, it sits somewhere around a small lawnmower. I encountered a few ball jams which shut down the machine and a couple of instances of hitting the bag near the launcher which also stopped it. But for the most part the performance was pretty reliable.
The launch angle is controlled with an adjustable screw nob. It’s located in a zippered compartment near one of the wheels. It ranges from 0 to 40 degrees. Loosen the knob, put it on the desired angle and screw it tight. It’s not quite cutting-edge technology, but probably keeps the cost and weight down and is basically idiot-proof. The only inconvenience was if I wasn’t satisfied once the balls start slinging, I had to shut it down and make the adjustment. It certainly would be faster and easier to hit a button on the remote to raise or lower as desired.
An oscillator (sold separately) can add variety to the feeding direction. It’s a square plate that is positioned directly underneath the bag, with a power cord that magnetically attaches to the battery of the Slinger. It’s stable once running, but can be easily knocked off if struck with a ball. I happened to do that on a clay court, and some specs of clay stuck to the magnetic surface and caused some malfunctioning until I got it completely clean.
A button on the remote key activates oscillator. It methodically rotates the bag from side to side with no other variation. It will put an additional strain on the battery, but I never came close to a power failure over a 1.5-hour training session. The Slinger people claim it can go five hours on a full charge, which would only be a concern at a busy club. Recharging between each session—a full charge can take up to six hours—is recommended.
Execution with the oscillator took some trial and error. Even though I had the bag positioned in the middle of the court, some of the feeds were shooting wide of the doubles alley. And depending on how efficiently the balls were being slung, the variation of the feeds could be spotty. I could get a couple of rapid shots to my backhand corner, one down the middle and then nothing to my forehand corner.
But once I got the hang of where the bag needed to be for certain types of feeds and the best speed and frequency of the balls, the oscillation was ultimately a worthwhile addition. Even though you can anticipate the direction the ball will be fed it added enough randomness and movement to elevate the difficulty and conditioning levels of a training session.
However, I found the Slinger best for setting in place and honing a skill. I’d set it up to work on backhands—crosscourt then down the line—followed by an inside-out forehand. Or have it spit out floating short balls to work on mid-court put-aways (above). Putting the knobs at the lowest levels and raising the launch angle turns the Slinger into a caddie that spits out balls for serves like a coach standing by a hopper (below). When courts weren’t available, I even set it up in the driveway to work on drop shots and touch volleys. If you’re creative, the versatility of the Slinger Bag can be put to good use.
If you’re in the market for a new ball machine, the Slinger Bag is definitely worth considering. Like any version 1.0 technology, there are a couple of wrinkles that could stand some ironing. Ball jams could be lessened, the sound a bit more refined and oscillation fine-tuned. But the guts of a top-notch ball machine are all there. It’s easy to transport and use, quick to operate and delivers feeds that will provide great practice for a rank novice up to a serious ball-striker. The affordable price tag when compared to the competition is a nice bonus. If only you could share a beer with it.