Multi-rotors that are designed for First Person View (FPV) racing and sport flying continue to evolve. The Immersion RC Vortex 150 is a new machine that reflects many of the latest trends in the hobby. First of all, it's small. It measures just 156mm between diagonal motor shafts. This gives the quad a significantly smaller footprint than the 250mm-class ships that used to dominate quad racing. Yet, as you will see, the Vortex 150's bantam size does not make it any slower or less nimble.
Another innovative aspect of the Vortex 150 is that it is mostly prebuilt. A fair amount of building, soldering, and programming used to be required when setting up a racing quad. While those are all useful skills to have, they are no longer a prerequisite. You can learn as you go.
Vortex 150 Overview
The 150 is currently available as an Almost Ready-To-Fly (ARF) package ($300). It includes most of the components that would normally be purchased separately (carbon-fiber frame, brushless motors, propellers, electronic speed controls, flight controller, FPV camera, video transmitter). The only things left to add are a radio system with a micro-receiver, a 5.8Ghz video receiver (goggles or a monitor), and flight batteries.
Like the frame itself, all of the onboard components are similarly downsized. The tiny brushless motors are only 17mm in diameter and spin 76mm-diameter (3") 3-blade propellers. The flight battery is small too. You can fly with 3-cell or 4-cell packs with a capacity of about 500mAh. I've flown the Vortex 150 with a few different batteries, but my primary power sources have been Lumenier 4S-460mAh 45C batteries. This battery and the power lead on the quad come equipped with XT30 connectors.
One of my biggest challenges when building a racing quad is keeping all of the wiring neat and tidy. Space is always at a premium. And it's not just a matter of vanity. A stray wire can foul a prop or become damaged during a routine landing. None of that is a concern with the Vortex 150. Other than the receiver antennas and the power lead, all of the wiring is housed internally.
Many racing quads have two cameras: a low-latency analog camera for the FPV video signal, and a digital action cam (such as a GoPro or RunCam2) to record the flight in HD. While the Vortex 150 includes an analog camera, there is no factory provision for an add-on action cam. I'm sure there are a number of ways that one could hack a weight-conscious action cam mount with a little ingenuity.
The included FPV camera has 600 Television Line (TVL) resolution. It comes mounted in a plastic housing that provides some crash protection. The camera mount also allows the camera's tilt angle to be adjusted to the pilot's liking.
When flying with other FPV pilots, it is essential to manage the frequencies used by each video transmitter (VTX). Powering up a VTX with a frequency already in use is likely to cause the other pilot to crash. Since you should never use more output power than is necessary for a given situation, it is also handy to be able to control the power of your VTX.
Rather than using physical jumpers or buttons, the channel and power output of the Vortex 150's integrated Tramp VTX can be controlled externally. There are 48 channel options and power can be set from <1 milliwatt to 600 milliwatts. Some Spektrum-brand radios can be configured to control the VTX through an on-screen menu.
My first-generation Spektrum DX8 does not allow VTX control, so I used the Touch N Race (TNR) Wand ($50). This little handheld device allows you to control all aspects of the VTX just by holding it near the TNR tag on the starboard side of the frame. You don't even have to power up the VTX to make changes. I'm not sure how it works, but I'm pretty sure that pixie dust and chicken feet are involved.
Setting it Up
My usual gripe with multi-rotors is that the manuals are sparse or that the info is spread over different platforms (quick start guide, manual, videos, etc.). That is not the case here. Immersion RC provides an in-depth PDF assembly manual for the Vortex 150. It covers everything you need to know in a single resource.
Because the Vortex 150 is factory built, there is very little physical assembly to do. You'll need to attach the included VTX antenna. It uses common SMA connectors, so it is a very quick process.
Installing the receiver actually requires you to do a little preparatory disassembly. Removing the top plate of the frame provides access to the electronics within. The plate is held in place with eight Torx screws (6-point, star-shaped drive slot). I used a T10 Torx driver to remove them.
I used a tiny Spektrum SPM4648 receiver. The only necessary connection to the receiver is a 3-wire plug from the flight controller. Other plugs are provided to interface with FrSky, Futaba, or standard CPPM receivers. There isn't much internal space for the receiver, but the Spektrum unit fits well. Using anything larger than a postage stamp may require external mounting.
The LED lens on the rear of the Vortex has slots for routing the two receiver antennas. I positioned the antennas so that only the last 38mm (1.5") of each was exposed. I carefully bundled the rest inside. A small dab of GOOP on each exit slot keeps the antennas in place.
A Velcro strap is used to secure the flight battery to the top plate. The mounting area is very smooth. I was concerned that this would allow the battery to shift fore and aft during hard maneuvering. With the props in very close proximity to the battery, even a small shift could be bad news. I added a few small strips of self-adhesive foam padding to the mounting area to increase friction and help keep everything in place. So far, so good.
The Flight Controller (FC) is the core of any multi-rotor. The sensors and processors in the FC determine how the stable the ship is and how it reacts to your control inputs. All of my previous race quads have required me to connect the FC to my computer with a USB cable. I then had to use an interface program to configure the various parameters of the FC. Sometimes things go well the first time. Sometimes it takes trial and error to get it right.
Configuring the FC for the Vortex 150 is different…very different. Rather than hard-wiring the FC to your computer, the set-up menu is displayed through the quad's video system. You power up the Vortex (with the props removed) and tune into the video signal with your goggles (or a monitor). You then navigate the menus and work through the set-up steps using stick movements on your radio transmitter. It is very intuitive and fast. Best of all, you can tweak your FC setup at the field without having to bring along a computer.
The props are held in place with 5mm locknuts. Once the nylon locking feature is engaged, the nuts are quite tough to turn…especially the first time. Forget pliers. They'll just round off and mangle the painted hardware. Use an 8mm nut driver and hold the motor case firmly.
Because of the pre-built airframe and streamlined setup process, you can have the Vortex 150 ready for flight within an hour or two of opening the box. The included components integrate perfectly. I did not experience any hiccups. Even so, you should set aside enough time so that you can read the entire manual too.
In the next article, I'll talk about my experiences flying the Vortex 150 and all of the options for tuning its performance. Spoiler alert: it is currently my fastest racing quad!
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.