Quadcopters, drones, and other RC fun


#182

You’re the exact right person to ask: will a drone survive a direct hit from the Nemesis?


#183

No idea but I suspect it would be fine. Sounds like you need to science the shit out of this, my man… make it happen!

A few things I learned as a 100% n00b drone pilot, for that UDI U818A model we have

  • Start indoors, I think, in any room with about 4-5 feet of clear area. We had some (cough) bad luck learning the absolute basics while starting outdoors, and there’s the wind factor too. Those rotor protectors work!

  • Remember the white rotors are the “front” of the drone when operating. There’s also a bright white LED in the front, and the LED lights underneath are blue (front) / red (rear) to hint about orientation as well.

  • Another thing we kinda learned the hard way: follow the manual instructions on order of power-up. To launch: power up remote, then the drone. To shut down: power down drone, then the remote. Opposite order.

  • Mode 1 (beginner mode) limits how hard you can tilt the drone in any direction and is the default. We were wondering why we could barely move forward outside in a breeze and then I realized why. Switched to mode 2 (regular mode) and bam, now we’re cooking.

  • Grit and sand is hell on the gears that drive the props. I didn’t even realize this until we were testing on a baseball field and the props started acting a bit weird. I removed the tiny bits of grit in the gears with a knife and it’s OK so far. It does come with replacement gears, but only the tiny ones (there are two, one large, one tiny, per rotor). It also includes 4 replacement props!

  • There is an obvious beeping low battery alert on the controller, so you’ll know when to swap batteries (the kit comes with one extra). Extra batteries were super cheap, for $18 I got a 4 port charger and 5 more batteries. Very easy to swap out as well. We got about the promised 8 minutes of runtime per battery.

We have yet to use the video feature, I slapped the included 4gb SD card in there (they also include a USB reader) and we’ll give that a shot later.

Anyway this UDI U818A is great fun for me and my 8 year old son… at $47 I think it’s a fantastic deal and I heartily recommend it for any other drone n00bs like myself!


#184

Yep, yep and yep. :) I’ve tried hovering it above Smaug (well outside of his reach!) and he maintains his composure. We have already filmed some awesome footage of him death rolling a pig carcass from above.

It’s worth investing in a landing pad, you can buy these circular fabric things that pop out and fold back together for maybe 15 bucks. Either that, or just a rubber mat you can throw down on fairly flat ground.


#185

With Mavics and Phantoms we generally recover to the hands of someone other than the pilot flying. It looks dangerous at first, but my crews have been comfortable with it. For boat recovery I can’t imagine another way… I had some carrier landings before we started doing that :) (State-level natural resource agency/university setting)


#186

Do you turn off the downward sensors when hand-recovering the Mavics? I remember the first time I tried to hand-recover (after doing it all the time with the Phantom) and the Mavic went to full-throttle to try to get away from my hand. :)

Glad you’re enjoying the Mavic, Krayzkrok. That’s footage is awesome – can’t wait to see more.


#187

Absolutely, I hand launch and recover all the time now, I mentioned the landing pad to Wumpus who’s launching from a sandy substrate. The Montgomery Reef was my first hand capture, nerve-wracking as hell because I was in a small Zodiac which was drifting in the current. I have to do it by myself, which is fine for landing, but launching requires holding the controller against your chest while you swipe auto take-off, but it works.

@DennyA I just turn off the landing protection. In fact it’s off permanently now. I chipped a prop early on because the lag between command and execution caused the drone to drift into a slightly raised bit of rock just before touchdown. (I always land manually, don’t use the auto land function).


#188

I have a co-worker that ran his mavic into the side of a house. Don’t do that. His repair cost from DJI was half the purchase price.

Speaking of, how are you guys handling repairs you’ve needed to make?


#189

I have the DJI Care Refresh package, which is an annual insurance $169 (AU) to replace the drone twice in that time. There’s a small excess to pay, certainly not half the drone’s cost. While I’ve been ultra cautious with the flying, not to mention having put a lot of hours into it (plus other, larger drones, and flying with GPS off… which is scary), there’s always a risk of something going wrong or misjudging something. Pre-flight checks including scoping out the flying area properly goes a long way to avoiding unintentional incidents, but still it’s nice to have peace of mind.


#190

I bought DJI Care Refresh and used it on the one stupid crash I’ve had. So surprisingly, it was worth buying. Of course, I’ve had my Mavic for a year now, and I don’t think you can renew it…


#191

lol, you guys need to get some more sport oriented drones - crashing is a way of life. Makes you appreciated the automated systems on board the DJI et als.


#192

I presumed you can just buy a new package every year. Is that not the case? Either way, I will almost certainly be upgrading the drone on a regular basis anyway.

I had one of those “toy” helicopter drones from a few years back. I think I threw that thing against the wall several dozen times, always bounced off ready to fly again! Still, I’m tempted to get a cheap sports drone. The Mavic is actually a lot of fun in Sports mode, but I’m pretty nervous about flying it into a tree! The only near incident so far is I was racing the Mavic around a set of cones recently, getting faster and faster, except I finally overcooked a turn and it ended up skidding towards me at shoulder height. I ducked.

The main appeal of the sports drones is not having GPS assistance. :)


#193

Well for what it’s worth, they did give him great feedback and a breakdown of what was broken and the repair time. He was also back up and flying with it fairly quickly.

Back in my RC car days, though, you could source a lot of spare parts. I’m really surprised with chinese manufacturing of nearly anything and 3D printing that someone hasn’t picked up the slack here with a 3rd party solution similar to phone repair places.


#194

The only really silly thing I’ve done so far is fly the drone under a large road bridge, while I was standing on the bridge. There was plenty of room above the river and between the supports, but I was taking a bit of a risk that the signal didn’t drop out while it was under the bridge, switch into RTH mode, try to rise to whatever height I had it set to (40 meters I think) and smack into the underside of the bridge. Still, it was a nice shot. ;)


#195

So this is weird:


#196

We made our first videos using the inexpensive UDI U818A I referenced earlier. They came out OK, 1280x720, fixed camera position of course, written to the 4GB SD card that was bundled. Unfortunately when I upload them to YouTube they corrupt for some odd reason. The default Windows 10 media player absoutely hates these video files, too, but MPHC and other alternative video players open them fine.

video file format details
General
Format                         : AVI
Format/Info                    : Audio Video Interleave
File size                      : 84.1 MiB
Duration                       : 30s 767ms
Overall bit rate               : 22.9 Mbps

Video
ID                             : 0
Format                         : JPEG
Codec ID                       : MJPG
Duration                       : 30s 767ms
Bit rate                       : 22.4 Mbps
Width                          : 1 280 pixels
Height                         : 720 pixels
Display aspect ratio           : 16:9
Frame rate                     : 30.000 fps
Color space                    : YUV
Chroma subsampling             : 4:2:2
Bit depth                      : 8 bits
Compression mode               : Lossy
Bits/(Pixel*Frame)             : 0.810
Stream size                    : 82.2 MiB (98%)

Audio
ID                             : 1
Format                         : PCM
Format settings, Endianness    : Little
Format settings, Sign          : Signed
Codec ID                       : 1
Duration                       : 30s 0ms
Bit rate mode                  : Constant
Bit rate                       : 512 Kbps
Channel(s)                     : 1 channel
Sampling rate                  : 32.0 KHz
Bit depth                      : 16 bits
Stream size                    : 1.83 MiB (2%)
Alignment                      : Aligned on interleaves
Interleave, duration           : 1026 ms (30.77 video frames)

Why the heck do they even have an audio track on these video files, all you can hear is the super loud whine of the rotors anyway?

I did notice that having a SD card active reduces battery life, especially when recording video! I suppose that is expected.

I also tested how far you can fly with the low battery warning on the controller and it’s quite forgiving – maybe last 10-15% even? Eventually you’ll notice you have to give it more and more throttle than usual, and that’s when you absolutely want to start reeling it in. But you don’t need to land the minute the beeping starts.

We’ve had a few minor spills and the drone is plenty survivable, so I continue to recommend this model if you want to dip your feet in the water. Price seems to have gone up to around $55-$60 versus the $47 I paid, so I dunno!


#197

It’s more important when you’re paying bigger bucks for larger, higher capacity LiPo’s in the more serious craft. LiPo’s dislike being discharged too low - it reduces their longevity and can lead to more serious problems including increasing the risk of catastrophic failure and fire during crashes or charging/discharging cycles.

If you get serious in this, everyone should get themselves a LiPo battery bag for charging btw. They are cheap and the general consensus is that LiPos are not something you should leave charging unattended. Again, YMMV with risk factor on these smaller drones with tiny batteries, but it is a good safety habit to get into early.


#198

Not utterly surprising: GoPro drops its drone endeavor, lays off 250.


#199

Yeah, their drone was impressive for, what, three days until DJI announced the Mavic? And then the power debacle/recall with videos of them falling from the sky pretty much doomed them.

I love how they’re blaming the regulatory environment. The Karma was too little (or too big, actually), too late.


#200

I want to get one of those DJI drones, but I don’t really want to go through the deal of getting permission to fly it since I live within 5 miles of a tiny airport.


#201