
The Trippy, High-Speed World of Drone Racing - smoyer
https://www.newyorker.com/magazine/2018/02/05/the-trippy-high-speed-world-of-drone-racing
======
gmurphy
I design and build my own quads, though I'm not a particularly great flier.
The thing I love about the hobby is that it combines three key things:

* The control joy/mastery feeling you get from activities like car racing, riding a bike on technical terrain, playing a game, or flying a plane[1].

* A sufficient risk/reward profile; you risk smashing a $100 device, which is expensive enough to be interesting, but low enough not to be paralyzing

* The gearhead thrill of ordering, rebuilding, designing, and discovering new combinations of equipment

In my case, I want to optimize for quietness and unobtrusiveness, which means
aiming for lightness, which is its own set of fun design problems - I'm
currently down to 25 grams for a brushless FPV setup[2]. Now I'm on to
redesigning the RC transmitter[3], since I want one with nice gimbals that
takes up as little space in my bag as possible. The set of things you can do
is endless.

[1] I hooked up an RC controller and went FPV with my home flightsim setup. It
was fun, but there's a reason RC sticks are tiny - you need to move them
around a lot more frequently and quickly than in a plane:
[https://twitter.com/gmurphy/status/832698732361551872](https://twitter.com/gmurphy/status/832698732361551872)

[2]
[https://www.instagram.com/p/BaSymwPH7XJ/](https://www.instagram.com/p/BaSymwPH7XJ/)

[3]
[https://www.instagram.com/p/BdnapxGltfw/](https://www.instagram.com/p/BdnapxGltfw/)

~~~
eltoozero
Nice clean build, what frame is that?

Just bought a pair of fly egg 100’s frames (not kits) for a tiny build but I
was planning on deleting the “cage”.

The FrSky TX is quite a project too, very interesting. You got a write up or
project page somewhere?

~~~
gmurphy
It's a 2g frame and camera mount I designed - you can download the plans here
(the button next to the QTY selector):
[https://armattanproductions.com/pages/product_details/12158](https://armattanproductions.com/pages/product_details/12158)

The TX is a Jumper T8SG + FrSky M9 gimbals and recased into a 3D printed case
I made. Haven't finished it yet (waiting on a third iteration to be printed),
so writeup when I'm done :)

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monktastic1
"Maybe someday we’ll all be flying in commercial airplanes directed by calm,
professional, reassuring pilots who are sitting on the ground."

Color me old-fashioned, but I like it when my pilot has some skin in the game.

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semi-extrinsic
I recently saw a very interesting CFD study by NASA recently on drone
configurations, where they found that a hybrid version with front rotors below
the frame and rear rotors above was significantly faster, since the wakes
interact less. Wonder if it's been tried on racing drones?

[https://www.nas.nasa.gov/publications/articles/feature_hybri...](https://www.nas.nasa.gov/publications/articles/feature_hybrid_UAVs_VenturaDiaz.html)

(The flow simulation and visualization in the above link is so insanely high
resolution it's borderline pornographic.)

~~~
donkeyd
I'm not completely sure whether this is as relevant for racing drones as it is
for surveillance/video drones. Racing drones often fly at a 45+ degree angle,
so the thrust is angled more backwards than downwards. Also, one of the
benefits of the NASA research is longer flights. But racers often don't fly
more than 1-2 minutes, after which they swap batteries. A slightly lighter
battery could give the benefit of slightly quicker acceleration though and
that's pretty important. Lastly, in the pro leagues, they usually fly the same
drone, so there's no need to have the fastest drone.

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wehadfun
Drone racing was on like ESPN 8 one day and it was very interesting to watch.
Honestly if E-Sprots/Nascar have a following this should as well.

~~~
wyldfire
I can't tell if this is serious. Do we really have "the ocho" now?

~~~
Qworg
ESPN: College was taken over for a single day as "The Ocho" last year:

[https://www.sbnation.com/lookit/2017/8/3/16091446/espn8-the-...](https://www.sbnation.com/lookit/2017/8/3/16091446/espn8-the-
ocho-real-tv-channel)

[https://www.youtube.com/watch?v=jow5hZPF3zY](https://www.youtube.com/watch?v=jow5hZPF3zY)

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lawlessone
love this quote "An immeasurable amount of scientific and technological
progress, like a huge invisible inverted pyramid, converges on this small,
toylike point. "

~~~
abakker
A friend of mine in the drone racing/stunt hobby said something to me the
other day that really blew me away, "the real improvement in drones in the
last 2 years isn't batteries, it's that the output of the motors has increased
so much that we've all dropped a frame size and kept the same output." He then
said that it might happen again soon.

I don't know if that means that the real output of the motor is truly
increasing that fast, or the effective output taking into consideration the
reduced weight, but those little motors putting out a ton of power, very
efficiently.

The combo of brushless DC motors and lithium batteries more or less
revolutionizes everything it touches.

~~~
halbritt
Max output of a motor is constrained by weight, or more specifically, its
ability to dissipate heat. Racing quads generally use 30-40 gram motors. The
top racing motors these days produce 1.6kg of thrust at max output and consume
40 amps of power in the process. It's not difficult to produce a quad under
500 grams.

4 motors would produce 6.4kg of total thrust for a 500 gram quad for a nearly
12.8:1 thrust/weight ratio at a 160 amp current draw. A few years ago a 4:1
thrust/weight ratio was considered pretty good.

160 amps might be a stretch, but it's not uncommon to get >100A out of a
1300mah battery.

All that is pretty crazy, but I think the more interesting bits are in the
open source efforts around flight controllers and speed controllers.

~~~
bradfa
With those kinds of currents, it'll be interesting to see if point of load DC-
DC converters become integrated into the motors themselves so as to reduce the
wiring requirements for distributing the power to the motors. The batteries
will need to stack more cells in series to support this but I wonder at what
currents the wire gauge, and hence weight of the wires, become a big concern.

Maybe modern quads already do this?

~~~
halbritt
Wire runs are so short and peak current is so brief that it effectively
doesn't matter.

Most folks run 14AWG between the battery and the power distribution board.
PDBs are generally made with 2oz copper and wide traces to accommodate the
current, from there, the total current load is divided by 4, assuming that's
how many motors or running.

~~~
jsjohnst
> Wire runs are so short

This! The length of wire makes a huge difference in rated capacity.

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caio1982
The embedded video is well worth of watching! Trippy indeed.

