Brushed vs. Brushless Micro Quadcopters
Written by Matt Ruddick Can the new technology brush away the old standard? Product Review As seen in the May 2019 issue of Model Aviation.
At the end of 2018 and into the beginning of 2019, the landscape of micro drones began shifting sharply in a new direction—a direction pointing toward new, slightly larger micros with brushless motors. Until this point, mainstream micro drones were using less powerful brushed motors for a variety of reasons. They were cheaper, smaller, and more suited for indoor flight.
We now find ourselves with more choices thanks to the smaller and less powerful brushless motors that have entered the market and brought with them enticing new quadcopters, checking many of the boxes that experienced FPV pilots are looking for. They have the ability to perform the same aerobatic maueuvers that can be done on larger mini quad rigs, and, of course, they have more speed!
But as I sat back to watch these new brushless quads take off, I began thinking about whether a brushless-powered micro drone would actually perform better across the board. How would a brushed quad stack up against a brushless quad in a real-world situation?
First, what are the actual advantages to flying a brushless micro quadcopter? A few easy ones come to mind, such as top-end speed. You can expect a brushless setup to give you more speed for longer distances.
You’ll also expect a more responsive feel with your inputs and generally tighter handling, although other factors can play into this. Brushless motors often last much longer than a brushed motor set. Many brushed motors are rated to last for approximately 5 to 7 hours of use, while brushless motors can last significantly longer than that if treated with care.
So, that seems like an easy choice, right? Well, not exactly. Brushed motors have their own set of perks. First, they’re less expensive than their brushless brothers. At roughly half the price, brushed motors are easier to pick up and keep spares on hand. They’re also suited for smaller flying areas, such as home courses and smaller race tracks. Their ability to be nimble at lower speeds makes navigating smaller spaces an easier task, and they are often considered to be safer thanks to the slower rpm.
With those points in mind, what should we expect when flying the same course with a brushed micro quad and a brushless micro quadcopter?
I tested four quadcopters on the same indoor course. There were numerous tight turns, gates, and obstacles to avoid, along with a couple of longer straights where speed could be a factor.
The brushed quads I used were an AcroBee from NewBeeDrone that featured the BeeBrain Lite flight controller and a Tiny Whoop racer. The brushless quads I used in testing were a Happymodel Mobula7 and a Blade Inductrix BL. It’s worth noting that each quadcopter was flown in Angle mode for these tests.
First, from a handling standpoint, I found that each quad had its benefits. As an example, the Mobula7 flew as though it was on rails, holding tight to each turn and carrying speed when needed. However, the extra speed I would carry down the straights forced me to slow down more often to make the turns, compared with the brushed models. The AcroBee was comfortable and effortless in flight, requiring less stick precision and yielding smoother lines throughout the course.
What surprised me the most, however, was the lap times. Using the Whoop Laps app for Apple iOS, I kept finding that my lap times were comparable across the board. After 10 runs on each model, the average lap time for the brushed quads was 0:34.9 seconds, while the average lap time for the brushless quadcopters came in at 0:33.4 seconds.
So, does that mean that a brushless quad is the winner in this head-to-head comparison? Well, not exactly. Although the brushless pair averaged 1.5 seconds faster on my test track, I felt more comfortable flying the AcroBee than either of the brushless quads. I was calmer throughout the runs, which resulted in what I felt was a smoother flight experience. This leads me to my secondary test: the head-to-head race.
If races could be finalized after the qualifying rounds, many would have different outcomes, and this test was no different. I decided to put the Mobula7against the AcroBee in a series of head-to-head races to find out if the lap times would translate to a real race situation.
As I suspected, the tight turns and obstacles on the track were easier to navigate using the brushed models; however, what surprised me was the ability of the brushed quads to stay on pace down the straights alongside the Mobula7 and Inductrix BL. In fact, in a couple of instances, I found the AcroBee passing the Mobula7 while drag racing down the straights before approaching a sweeping left turn.
What I found was that race after race ended, and neither side came out with any dominance. Of the 10 races, six were won by one of the brushed quadcopters, and four were won by one of the brushless aircraft. This less-than-scientific result was certainly one that I had not expected.
I wasn’t sure which side would come out on top, but I was certain that there would be a clear winner. The data proved me wrong in this instance. My observation that I felt more comfortable flying the AcroBee than either of the brushless quads got me thinking that it might be possible for the performance differential to be offset by the comfort level and familiarity of the pilot.
Although it might not be as simple as stating that one choice is better than the other, it’s also not as simple to say that newer is always better. I, for one, won’t be retiring my brushed micro quads any time soon, but I plan to give these new brushless beauties a little time to settle in. After some practice, they just might find a new home in my fleet.
Sources:
NewBeeDrone
Tiny Whoop
Whoop Labs
Happymodel
Blade
(800) 338-4639
This Month's Issue
Join the AMA
Add new comment