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Posted by mandevil | Nov 04, 2016 @ 01:33 PM | 831 Views
Yesterday, I dodged not one, but two bullets while flying my F550 hexacopter.

The first close call happened as I was flying near Vimperk. I flew to about 100 m AGL to gain a view of the town. After short while filming I decided to return. And guess what, I couldn't find my starting place no matter what I tried. Video link got quite spotty and I thought I am above myself, but in fact I was behind some trees and not very close. I tried to recognize the terrain (meadows with groves) but I couldn't no matter how hard I tried. Eventually, I decided that it's better to land at unknown place than to fall while searching fruitlessly. Fortunately, the craft did not lose the control link (that would trigger RTH which I don't think would work as I suspect that GPS fix was lost). After about 15-30 minutes I found the copter intact in the middle of a meadow. Video from the camera eventually showed, that the landing was fairly smooth, if bit fast.

The second close call happened on different place, where I decided to finish off the same battery from the previous flight. It was showing 14.75 V (4S battery) or so, so I thought I can eke out a minute or two. Bad decision. After I reached my target some 300 m away I noticed that my main voltage is 9 V! Before I could do anything, the copter started to descend rapidly. Fortunately, I was just a few metres above the ground, but even then the impact was more violent then in my previous screw up. The landing gear legs snapped on one side, but apparently gimbal did not hit the ground. So it seems nothing but the landing gear broke. Of course, now I need to order new one, before I fly again.

Lessons learned:
  • on unfamiliar location don't just fly away, but look back and find some orientation landmarks that will help you find your way back
  • make sure you're receiving GPS coordinates in telemetry; make sure your transmitter is displaying all pertinent navigational data: AGL height, ground range, distance!
  • have alarm for low voltage that triggers at about 13 V

Edit: Video of the above is available.
Posted by mandevil | Oct 31, 2016 @ 05:21 PM | 780 Views
Third session with my DJI F550 hexacopter with new Zhiyun Tech Z1 Tiny 2 gimbal. Very roughly edited because I'm on vacation and don't have real editing software here.

Aerial from Šumava (quick edit) (5 min 39 sec)


The occasional vibrations occured again. They never happen when low, sometimes just turning into opposite direction will make the flight smooth again. I am more and more conviced it's the prop downwash impinging on the gimbal platform. I tried to move the gimbal back a bit, but no discernible improvement. But it definitely needs to be resolved, since it seems to be able to ruin otherwise good shot.
Posted by mandevil | Oct 28, 2016 @ 03:51 PM | 723 Views
So, as promised, today I took the Zhiyun Tech Z1 Tiny 2 brushless gimbal to flight. I compiled a video from today's footage (total of about 24 minutes cut down to some 6 minutes). I couldn't do much processing since I'm on vacation and my video editing workstation is not with me.

Overall, good impression -- it just works. Horizon is level, heading stays put, stabilization looks mostly pretty good. There were some periods where there were considerable vibrations visible. Not sure about that, but either there was some wind up there or something is not quite right with the copter.

I don't have video switching in the copter yet, so I couldn't try remote control of the gimbal.

Zhiyun Tech Z1 Tiny 2 gimbal maiden flight (7 min 0 sec)

Posted by mandevil | Oct 27, 2016 @ 02:07 PM | 487 Views
I completed equipping my F550 hexacopter with Zhiyun Tech Z1 Tiny 2 gimbal. Since I am on a vacation, it's not the final solution yet, but it should be airworthy enough for a few flights.
  • Had to extend gimbal control wires; spent entire evening making JR connectors agonizing without proper tools
  • The hang frame supplied with the gimbal does not fit my landing gear's rail I decided that I will just affix the gimbal's top plate to the rail platform but I don't have the screws/nuts for that; temporary solution: duct tape! Much professional, much strong, much wow!
  • Mode selection doesn't work on the completed rig. Not sure what went wrong, I checked both the cable and the mode setting before installing. I don't want to take everything apart again, so default mode will have to do.
  • Takeoff weight is 2 kg. DJI spec says it should fly.

See you tomorrow.
Posted by mandevil | Oct 26, 2016 @ 06:31 AM | 650 Views
I ordered Zhiyun Tech Z1 Tiny 2 gimbal after reading positive reviews and good experience with it. Also, Banggood had it in their European warehouse and for a good price (about 30 EUR lower than in their China warehouse!) It arrived in about 10 days -- just few days before my vacation.

So now I am in the process of adapting the F550 so that I can install the gimbal. I installed the "tall legs" landing gear that include a rail for installing the gimbal. Unfortunately, the rails spacing cannot be adjusted and of course, it doesn't match the Z1 Tiny's hang-mount frame. So I will just screw it in the gimbal mount plate supplied with the landing gear (being on vacation, I don't have the screws...). BTW, I don't feel too good about the landing gear as it seems that both plates extend will into the down-wash of four out of six props.
Posted by mandevil | Oct 03, 2016 @ 03:34 PM | 1,132 Views
Had the third flight with my DJI F550 hexacopter. The first thing I did was to fly to the edge of the forest in distance... turned out to be at 700 m range. The video link was flawless. I'm very satisfied with my VTX/VRX performance so far. I get bit nervous when flying beyond LoS (which really is anything beyond in excess of 200 m), but hopefully I'll soon try to reach 1 km, weather cooperating.

Here is the video of the "long range" trip:

FPV flight #3: 700 m range reached (DJI F550 hexacopter) (3 min 13 sec)


Unfortunately, the Eachine DVR that's integrated with their LCD8502D diversity receiver is really crappy and barely usable. It records video at some non standard framerate (worked out as 16.9234 fps for me), which makes it difficult to match with the primary video. What a shame. Below is an example of what it records (taken on my FPV session #2). It took me the whole evening to be able to match the video with the GoPro footage and even then it's not perfect. Also there's noticeable tearing in the picture.

Second DJI F550 FPV Flight, with DVR recording this time (repost) (4 min 35 sec)
...Continue Reading
Posted by mandevil | Sep 26, 2016 @ 02:56 AM | 4,655 Views
Finally, after all that time procrastinating, I had my first FPV flight. I thought my Sky Surfer will be the first to fly, but equipping the F550 turned to be much easier with some velcro and binding wire. Currently I use extra battery to power VTX/camera, which adds about 140 g of weight.

Everything worked out beautifully. The video link was absolutely clear with no static whatsoever. I only dared to max 280 m away from myself. I will put together short video later today.

Can't wait to fly again.

Update: Here's the video. No sound, just a quick edit.

My First FPV Flight (DJI F550) (6 min 54 sec)

Posted by mandevil | Aug 22, 2016 @ 08:15 AM | 1,930 Views
After some waiting, my FPV kit is mostly complete:
  • Eachine LCD5802D as LCD display with integrated 5.8 GHz diversity receiver and DVR
  • Eachine ET600R 600 mW 5.8 GHz video transmitter
  • pair of Aomway cloverleaf antennas
I forgot to order the camera, though, so there's some more wait. Meanwhile, I range tested with my GoPro (thanks to Eachine to supplying two cables with their VTX, so that I could use one for the testing). I range tested by walking away from the transmitter with the receiver. The picture was perfect to about 300 m, then it started to exhibit some minor graininess. By 500 m mark the picture degraded quite a lot. I would be still able to control the aircraft, but it wasn't pleasant. I don't have much experience with this, but given how low both the transmitter and receiver were above the ground, I can only assume lot of the quality loss could be attributed by the Fresnel zone 1 getting big enough to be blocked by the ground.
Posted by mandevil | Aug 02, 2016 @ 08:07 AM | 1,558 Views
For ages I had selected several clips that didn't fit anywhere else and I wanted to give them some kind of home. That is, to compile them into a video. Finally got around to complete the job. It's nothing special really, just some random bits and pieces.

Anyway, as I was editing this, I got bit tired with Sony Vegas and decided to try DaVinci Resolve as NLE. I think it worked well enough that I want to repeat the experience. Few words about my Resolve impressions are below the video embed.

Compilation of unused aerial footage (5 min 25 sec)


Totally Green Video Editor's Impression of DaVinci Resolve

I was fairly conversant with Sony Vegas and I liked the way basic timeline editing was implemented in it. There were some problems, though. The UI wasn't properly supporting high DPI displays; when using Lagarith VfW codec, audio playback lagged terribly; crashes were a thing. Then I have found out that Resolve 12.5 is free to download and use. Free as in free. Wow. Let's give it a go! I edited two little videos and I think I have switched for good.
  • UI works beautifully on 4K HiDPI display; no more broken menus; no more microscopic type; letters are properly scaled, everyhing looks gorgeous
  • VfW is not supported at all; good bye Lagarith. Looking for an intermediate format, I converged on using Apple ProRes -- the format is supported by Resolve for reading and ffmpeg supports encoding it. What's better, I can write Deshaker output directly into ffmpeg ProRes
...Continue Reading
Posted by mandevil | Apr 10, 2016 @ 01:44 PM | 2,093 Views
After not much happening during the winter, I have ordered and received some new gear. The first one is FrSky Taranis X9D+ TX with X8R RX module. This means I have RX for each F550 hex and Super Sky Surfer. I also ordered Zaggometry, so I can receive telemetry from Naza M V2 flight controller. And the last order were two more 5 Ah LiPos, so I can finally get more training time.

Now if weather would cooperate...
Posted by mandevil | Nov 01, 2015 @ 03:28 AM | 3,896 Views
Yesterday I maidened my F550. Everything went smoothly.

DJI F550 Hexacopter Maiden Flight (6 min 36 sec)

Posted by mandevil | Oct 30, 2015 @ 01:02 PM | 2,680 Views
The (initial) work is done, my bare-bones F550 hexacopter is ready for its maiden flight tomorrow. Building from ARF kit wasn't too involved, though at times I wished the manufacturer actually had written something useful in the user's manual (recommended placement of stuff mainly).
Posted by mandevil | Oct 16, 2015 @ 05:26 PM | 2,709 Views
Gf wants me to do some nice aerial videos and all that... so after long time avoiding this topic, we're planning to get a real multirotor for aerial photography. After lot of deliberation, the choice is:
  • DJI F550 "Flamewheel" hexacopter frame in kit (with E300 propulsion)
  • DJI Naza M V2 (mainly because it allows for clean landing with one motor disabled)

After the craft is flying reliably, I would add a camera gimbal mount for my GoPro Hero 4. Not sure which at the moment. The contenders are Tarot T-2D, DYS Smart3 ... or something else altogether.

We'll see tomorrow, nothing's ordered yet.

UPDATE: Ordered!
Posted by mandevil | Feb 24, 2015 @ 03:17 PM | 4,018 Views
Here is compilation from 2014 footage from my Super Sky Surfer 2,4-m wingspan EPP plane.

Super Sky Surfer - The First Year (6 min 49 sec)

Posted by mandevil | Sep 27, 2014 @ 02:09 PM | 2,827 Views
On the last day of my vacation at our favorite place I was to show the plane to a visit from my girlfriends' father and his wife. Well, it didn't go as planned. Shortly after the launch the stock moter seized up and I had a forced landing (without any damage, luckily). I shudder to think what might happen on my previous flights. Here's the video from the abortive flight, in the audio you can hear the chatter of the seized motor.

Super Sky Surfer – Stock motor seizes up shortly after a launch (0 min 53 sec)

Posted by mandevil | Jul 13, 2014 @ 03:09 PM | 3,387 Views
Yesterday I took my Super Sky Surfer out, this time with the second 5 Ah battery, which turned out to be faulty. One of the cells can't be fully charged. I wanted to know how will it perform -- it performs noticeably worse than my first battery and on the end I actually had the three good cells at 3.6 V and the bad one at 3.2 V. It also seems very soft, I actually aborted third launch because just putting in full throttle made the undervoltage protection to kick in.

Anyway, the flight was actually rather nice, even if it was somewhat windy. I tried to reach clouds that seemed to be fairly low, but they probably weren't low enough. Anyway, as I was gliding down, I noticed buzzards circling around so I joined. Not sure if it was thermal or slope lift (there was gentle downslope), but it was definitely there. Not enough to keep me afloat, but it definitely slowed my descent substantially. And surprisingly enough, I even got one close encounter with one of the birds on video. Here's the picture, the video will hopefully come later. The quality isn't great, but still, it's my first such encounter.


Posted by mandevil | Jun 29, 2014 @ 03:40 AM | 3,231 Views
I put back the stock motor and bought new undrilled 9x6 propeller and went for a test flight. The vibration are much less pronounced, almost unnoticeable for the most part. It was rather windy, so the video was not as stable as the previous one. I made some high ascents (I assume the highest being to some 300 m). Apparently, there was some slope lift at the place, because my first glide (from the lowest height!) lasted almost 10 minutes (with heavy 5000 mAh battery and a GoPro in original housing), which is pretty impressive. At those distances I'm getting frequent RSSI beeps from my FrSky transmitter, wonder if the default setting is too conservative. I made total of three ascents. The last glide had to be aborted because of approaching air ambulance helicopter -- the abort with flaps and nose down worked nicely and I was on the ground in about 30 seconds (from less than 100 m, though).
Posted by mandevil | Jun 13, 2014 @ 08:54 AM | 3,200 Views
I have replaced the stock motor with Turnigy D3536/5 1450 KV outrunner. I had to redrill the propeller, since the new motor has wider shaft. When I finally got to flight test it, it performed well, but something (probably the hole drilling) is not right, since there is quite strong vibrations. With the stock motor there were no noticeable vibration even over 50% throttle, but with the new one, most of the powered flight gives useless video. The flight as such, however, is nicely stable, as you can see from the video containing mainly the gliding sections of the test flight. Note: the video is just a test, it's long and has no sound.

Super Sky Surfer - Test camera flight (9 min 12 sec)

Posted by mandevil | Apr 30, 2014 @ 09:13 AM | 3,754 Views
I have finally finished video from last year's vacation.

Vacation in Kopec, part two (3 min 50 sec)

Posted by mandevil | Apr 28, 2014 @ 05:59 AM | 3,270 Views
After almost three monts my Super Sky Surfer flies again. All servos are replaced with PowerHD 1711MH, ESC is now Hobbyking YEP 60A and power source is 5000 mAh 4S battery. I also have replacement motor, but I will need to redrill the propeller, so that's not in yet. I had two flight sessions including one with camera on. The plane flies OK, but the tendency to roll left is till there, so this is something to work on.

The next thing to do is to make some proper camera mount.

Some pictures from this weekend