At this time of year, winter weather forces many of us to scale back outdoor RC activities. But there is still plenty of fun to be had indoors, including multi-rotor FPV racing. Indoor FPV racing is becoming very popular for reasons that go beyond its weather advantages. Compared to outdoor FPV racers, these tiny indoor machines are less expensive and just as durable. It's also easy to set up a racing course right at home with just about anything you have on hand.
The machine responsible for kickstarting the current indoor racing boom is called the Tiny Whoop. It is basically a Blade Inductrix mini quad with more powerful motors, an FPV camera, and video transmitter added on. The first generation of Tiny Whoops were basement-builds by industrious pilots. Now, Blade has released a new version of the Inductrix that includes the hop-ups necessary for indoor FPV racing, the Inductrix FPV.
There are two versions of the Inductrix FPV. The Bind-N-Fly model ($100) includes the souped-up quad and a 200mAh LiPo flight battery. This is usually the preferred model for pilots who already own a Spektrum radio and FPV goggles. The Ready-to-Fly model ($200) adds a small transmitter as well as a 4.3" (109mm) video monitor. This package is for pilots who are starting from scratch. Horizon Hobby provided a Ready-to-Fly set for this review.
The Inductrix FPV is a small quad. It measures 64mm between diagonal motor shafts. Once you factor in the propeller shrouds, the diagonal dimension is just over 100mm. Those shrouds are very important aspects of the Inductrix's suitability for indoor FPV. Not only do they protect the props and whatever you crash into, the shrouds also act like cushions to soften the blow. I can't tell you how many times I've flown into something, only to have the quad bounce back in the other direction while still flying. It is probably the most crash-resistant indoor quad I've ever flown.
The onboard FPV gear consists of a tiny camera with an integrated 25-milliwatt 5.8GHz video transmitter (VTX). An amateur radio license is required to legally operate this VTX in the US. This system can broadcast on 16 different channels, including the new Raceband frequencies. These components are housed within a protective plastic shell that screws to the quad frame.
On the receiving end of the video signals is the monitor with a built-in 5.8GHz receiver. This unit includes an integrated battery that is charged via micro-USB. A large spring-loaded clamp is provided to allow you to attach the monitor to the top of the transmitter. The clamp is a handy option, but it does not grip the monitor as securely as I would like. Spektrum also sells a headset adapter ($55) that allows you to utilize the monitor like goggles.
You can tune in to the video link using pretty much any device intended for 5.8GHz video signals. All of my devices can pick up at least a few of the VTX's channel options. So far, I've used the included monitor, my FatShark Teleporter goggles and my Tactic FPV Wrist Monitor. All of them worked just fine.
The transmitter will feel familiar for anyone who has flown other Ready-to-Fly models from Blade, E-flite or Parkzone. It's basic, but it is comfortable for thumb flyers or those who, like me, use a pinch-grip. Of course, you can always link a standard Spektrum transmitter to the Inductrix FPV if you want to take advantage of the enhanced tuning options that a computer radio offers.
Flying the Inductrix FPV
Even with the rudimentary transmitter, the Inductrix FPV provides two control rate options and two flight modes. You can select high-rate (more sensitive controls) or low-rate (more docile controls) by pressing axially on the right control stick. The two flight modes are Stability and Agility. These modes are selected by pressing axially on the left control stick. By default, the transmitter is set to high-rate controls and Stability mode each time it is powered on.
In Stability mode, the quad will self-level when you release the right control stick. There are limits to how far it will tilt in any direction. This is commonly referred to as Attitude mode in the multi-rotor world. Agility mode has no self-leveling function or bank limits. It is equivalent to what is usually called Rate mode.
I began flying the Inductrix FPV by line-of-sight in Stability mode. The controls are very crisp and responsive even in low-rate. It's probably a bit aggressive for beginning pilots. As long as they take it easy and approach things in a slow graduated manner, I think this quad could be used as a trainer. However, I'd still recommend starting out with something more docile to improve your chances of success.
Agility mode offers more precise control, but it is definitely more challenging to fly. If you're considering an outdoor race quad (which is typically flown in rate mode) this is a good (and resilient) platform to get your feet wet. However, if your goal is to fly Agility mode with the Inductrix FPV, you will probably also want to use a computer transmitter to fine tune things. For instance, flips and rolls aren't really feasible even on high-rate with the included transmitter.
Switching to FPV is a whole different experience. Common surroundings take on a whole new look through the quad's lens. I can fly to any corner of my house, including the basement, and still get good video reception. I've flown other indoor FPV ships in my house, so I already had a rough idea for a few reasonable race courses and a baseline for the speeds I could fly through them.
I found that I most enjoy flying this ship in Stability mode with high-rate controls. It is really fast--at least it feels really fast zipping down a hallway just inches above the floor. It is also extremely nimble. My natural tendency is to slow down in preparation for making a 90-degree turn into a doorway. But it really isn't necessary most of the time. I've learned that if I keep the power on and take the turn aggressively, the little quad will change direction like a hummingbird. If I flub the turn and smash into something, it's usually of no consequence. Even if it gets knocked to the ground, I'm good to go as long as it lands right-side-up.
While the Inductrix FPV is certainly peppy, there are times when it gets behind the power curve. If you try to descend too quickly, you may not have sufficient power to arrest the fall before you hit the ground. This is especially true near the end of a flight when the battery voltage begins to sag.
One thing that I'm still getting used to is just how small this machine is. It will fit through some very tight spaces! The real trick is having the skill to put the quad in the right spot to weave it through. Watch some videos of experts flying these things and you'll see what I mean.
My flights usually last between 3-4 minutes per battery. Recharging with the stock USB charger takes 45 minutes to an hour. Spare batteries are only $6 each. It's a good idea to keep a handful of them around so you can continue flying.
I think the biggest limitation with the Inductrix FPV is that there is no built-in provision to record your video. The only way to record is to use a video receiver in conjunction with a DVR. It works fine, but you are also stuck recording any static in the downlink. An onboard recording option would be a great upgrade.
Make it Happen
Indoor FPV racing is a great low-buck, low-risk avenue for aspiring (or experienced) FPV pilots. It provides a lot of the same thrills as the larger and more powerful racing machines but without many of the limitations and overhead. The Blade Inductrix FPV is a robust package that provides everything you need to get started. Over time, you may even find that you prefer indoor racing over outdoor. I think I may have already turned that corner.
Terry is a freelance writer living in Lubbock, Texas. Visit his website at TerryDunn.org and follow him on Twitter and Facebook. You can also hear Terry talk about RC hobbies as one of the hosts of the RC Roundtable podcast.