TBS Discovery "Christine"
2-5-2015: After more hours of searching, some at night with a bright light, I could find not a single fragment of Christine. I got a slight case of poison oak stomping through the tall grasses in the area. She must be in the river. I wonder if the shielding I put on the GPS mount created too much resistance and pulled it down. I wonder if another flyer on 433 Mhz interfered with the DragonLink. The biggest change was the 1.3 Ghz video system, and I'm going to stay away from that for a while. I've completed setting up Gidget, a DJI 450 Flamewheel with a 2.4 ghz Walkera receiver and a 250mw Fatshark transmitter to start. She's got a securitycamera2000.com pilot camera, but no OSD or telemetry. Just something to get back in the air with. I connected the ImmersionRC Uno receiver to the ground station, or I can use the Fatsharks. Meanwhile, I'm looking at interesting new airframes, and I found a 23 Dbi patch antenna for 5.8 ghz that would look nice on a Myflydream antenna tracker. Hobbyking also sells an antenna deployment system that drops the video antenna down below the aircraft, far away from the other equipment. Wish I found it sooner.
2-1-2015: Christine lost. Beautiful day, calm wind, KP index 2. At about noon I took off for the second test flight around the park. Had 12 sats, and the noise was greatly reduced in video. I didn't notice how she was banking hard to starboard, and when I tried to turn to port she started dropping, and would not turn. No loss of signal, she remained in GPS mode all the way down. At the end she was dropping at 45 mph, and appeared to hit pavement. It took ten or fifteen minutes to get there, where I expected to find some kind of victem. Instead I found nothing. No wreckage, not even small pieces. I searched for 3 hours, at first by eye, then using the groundstation. The Garmin Etrex Legend was useless, too hard to use in a pinch. I walked the area again after dark, trying to light up her LED's with the remote. Nothing. Somebody probably picked her up, and since I have not received any call, I probably won't. I went back to the airfield in case she "went home", as the last flyers were packing up to go. Nobody saw her. She may have missed the road and ended up in the LA River. At least no victems.
1-31-2015: Relocated GPS systems all the way aft, and used a Low-Pass filter to extend the antenna ahead of the nose. Eureka! Getting 12 sats again in short order, even getting 9 indoors. Also re-installed the LC Filter I made earlier, which cleared up all the power noise in ground testing. I may remove the shielding on the GPS puck, it might not be needed, and creates air resistance. Will fly tomorrow to test.
1-25-2015: Flight test with shielded GPS antenna. Not good enough. Barely hangs on to six sats, and video looks great until motors powered up, then full of lines. Flew three batteries, all line of site. No trust in GPS, and video looks horrible. Flew early to avoid wind, pictures taken at dawn. The videos are on Youtube, at least the music is interesting, I hope.
1-24-2015: A test of the transmitter revealed how 1.3 Ghz beats up the GPS receiver. I see other folks buying aluminum shields for the GPS antenna, so I bought a roll of aluminum tape, and carefully cut pieces to wrap around the antenna protector that Christine came with. A ground wire runs from the nearby receiver to the shielding. It's not nearly as fast to lock as it was, but I got nine sats in a a few minutes, much better than before. The EZosd has a gps unit also, but it's right under the antenna, in a null zone. I'm now thinking about the DJI Black Box and OSD Pro PNP, which would replace both the Flytrex core, the Iosd mini, and the EZosd. They record (more) flight data for uploading to Flytrex, and pipe telemetry from the main GPS down to the antenna tracker. The OSD has everything I want, although it uses a pointer home indicator like the EZosd. At 1552 grams (that's 3 pounds, 6 3/4 ounces), Christine is very close to the 1600 gram maximum flying weight.
1-20-2015: Package arrived from readymadeRC.com, minus the patch antenna. While I'm waiting for it, I installed the new transmitter in Christine.I tried to move the 1.3 Ghz as far from the GPS as possible, but there seems to be some interference. Initial radio testing outdoors showed about half the normal satellites being located. I may end up moving the GPS further aft, or shielding the edge of the antenna closest to the transmitter. Still have to wire the audio from the receiver to the EZ antenna tracker, and tidy things up. Also setting up a repeater so I can use the Fatshark goggles wirelessly again.
1-12-2015: Ordered 1.3 Ghz radio gear from readymadeRC.com. Got the RMRC v4 receiver with 8dbi patch antenna, the gold budget US 1.5w transmitter, and a cloverleaf antenna for the transmitter. Not the most expensive, but this should be an improvement over 5.8 ghz. All I want is a solid three miles of range, even in a noisy urban environment.I tried to buy this stuff locally without success. There are two "brick and mortar" stores nearby. One favors "3d" helicopters and sells quads as a sideline, not carrying much in FPV stuff.The other has better selection, but doubles online prices and does not stock more expensive stuff I want, like Immersion's TX wattmeter. Neither have even heard of the really interesting stuff, like the HobbyKing battery internal resistance meter, or their flying vibration logger (which I have). While both sell batteries and chargers, none have charge bags either. These should be given away with every battery purchase, printed with store advertising.of course.
1-10-2015: Flew again today, just before the rain hit. Video quality improved by mounting between earplugs. No noticible interference from the DragonLink right under the GPS antenna. Balance change not noticable from moving battery forward. Battery seemed to run out very quickly. Need to buy the internal resistance meter. The DVR failed to record the first flight.
1-5-2015: Shaved the inside of the rear arms to allow battery to slide further forward. Moved the DragonLink radio forward, under the GPS antenna. I was concerned about the props contacting the wires sticking out both sides. Doesn't seem to interfere with GPS signal, or the video transmitter. Looks cleaner and moves balance point further forward. Just found out it's likely to rain next weekend, thinking of flying tomorrow before work. Sun up is 07:00 tomorrow. Found a fix for foggy Fatsharks on Youtube! Just punch some holes in the lower eye cup with a hole punch. I used a leather punch I have. So far that seems to work.Also looking at bigger 4S batteries. Candidates include the Glacier 6000 mah for $85, and the Luminier 5200mAh for $75 each.Currently using 4500mAh at $35 each. To stretch the power further I'm researching 4kv motors instead of the 9kv DJI motors I'm using now. They want 15" props, and my arms can barely handle the 10" I have now. The objective is to extend loiter time on target.
1-4-2015: The pilot cam was just hot-glued to the lower plate. In an attempt to improve the horrible video quality I glued it between some earplugs.Found out that acetone (in nail polish remover) dissolves hot glue clean off without damaging the boards. May make it worse, we'll see in next test flight.
12-27-2014: Here's what she looks like today, without the current sensor. You might notice the expert pilot checking out the video transmitter. The Flytrex Core is mounted under the top plate, and the EZosd is mounted where the GoPro belongs.You can see the DJI Iosd mini mounted atop the PMU2 power unit, and the DragonLink mounted sideways. The square part under the receiver connectors is the lighting relay.
12-26-2014: Took Christine apart, re-installed the DJI Iosd mini, and re-wired the system so audio only comes from the EZosd. Without the current sensor, the EZosd is powered by a spare receiver channel. I'll lose the RSSI for now, but recover the better, NAZA aware OSD. I should have bought the ImmersionRC Tiny Telemetry. For the moment I removed the LC Power filter, which didn't entirely fix my video quality problems. Someone at the field suggested mounting the DragonLink receiver transfersely, to protect the extra channel pins. It's too long to mount normally without those pins sticking out the back. He's right, it's much better this way. I mounted the Iosd atop the PMU unit. I still don't have the connector parts to make custom cables, so there's lots of spaghetti under the hood. Next test is Sunday.
12-24-2014: Thinking of removing the current sensor, and re-installing the Iosd. I can use the EZosd just for telemetry for the antenna tracker. I'll miss the Imperial measurements (in feet), but I get back the NAZA mode indication and better way home indicator. I should have bought the Tiny Telemetry unit instead. Maybe I can export Naza's GPS data directly to an encoder. Want to take Christine apart and shorten all the cables.
12-20-2014: Installed a LC power filter (made for two bucks) in the power line from the EZosd current sensor and the Video transmitter / camera. Seems to improve the video somewhat, still lots of hard drop-outs. Also flew the vibration detector, but don't know what to make of the data yet. Flew into uncharted territory east of Woodley. In pics below you'll see another quad in the air nearby, the hard drive disk I use to reflect the NAZA indicator light, and the vibration logger on the nose before flight.These pics were taken by my son CJ with his Iphone.
12-16-2014: Fixed my bad LIPO batteries as seen HERE. Accidently erased the data in the vibration logger, will try again next weekend. My Windows 7 system couldn't connect to it, but a Virtualbox Windows XP system working in Ubuntu worked fine. This week I've got to buy some nylon lock nuts for the props, and I think a power filter for the camera is needed. I picked up the Phantom yesterday, and now I know how they get 25 minutes out of a 3s battery. It's light. Christine is just plain heavy. I'm also less impressed with the dipole antenna on the DragonLink. They sell a long whip for it, and I think I'll try one. Wish I could live without the power sensor on the EZosd, it's heavy, ugly and in the way. The folding dolly worked great last weekend, even through the muddy grass. Waiting for the tools to crimp on the tiny connector pins found on this stuff. Inspiration is HERE. Shortening and maybe shielding all the wiring might clean up my video signal.
11-29-2014: Installed an EZosd to get GPS data down to a future antenna tracker. The way home indicator is hard to see in the Fatsharks. Have a 7" monitor on order which is what everyone suggested in the first place. But what fun would that be? I also need the EZtracker, but nobody has one locally. Flew today with stock antennas also, since I'm staying close by. Video looks better. Think I damaged the 600mw transmitter when the antenna fell off.Think I'll get one of those watt meters and check it.My $50 Hobby King DVR is pretty poor also.Little by little Christine is cleaning me out.
11-19-2014: Found the next piece of test gear I need: The 431000007-0 - X-CAM Vibration Tester with USB Adapter from Hobby King. It's only $35 bucks, and it'll let me balance all the motors and props on the bench, and in flying conditions. Installed pilot camera on Gidget, now using the Fatshark 250mw transmitter and RHCP antennas bought for Christine. Gidget will fly with the Walkera Devo 10 radio, no OSD or Flytrex data logging. Might be fun to set up Gidget as a recovery aircraft, with a releasable hook to snag other units in the trees, or up on roofs. Saw a Craigslist ad yesterday looking for a FPV operator to find a lost aircraft up on apartment rooftops. Also read the judgement of the NTSB finding that little quadcopters (even paper planes) are subject to FAA regulations. Some fixed-wing FPV pilot was fined $10k for reckless flying at the University of Virginia. Of course this is rediculous. If a pilot causes damage he or she should be liable for the damages. Insurance should be available, perhaps as a rider to car or home owner's insurance, like anything else. The idea that toy aircraft pilots should have pilot's licenses, and their aircraft certified airworthy is crazy. Personally I fly at low altitude, and fly away from people and breakables. To ensure safety I'm investing in tools and equipment to test and maintain the aircraft, replacing anything that might fail. And I constantly study and learn how to improve the aircraft. Much more time is spent studying and building than flying.
11-12-2014: Installed the DragonLink system, first flight doubled range record. Video transmitter antenna fell off, but I eventually found it in the brush. Running without an antenna didn't seem to damage the ImmersionRC transmitter.
11-9-2014: Need a little more range. Bought a DragonLink system, and some better antennas to improve video quality. The DragonLink transmitter plugs into the pilot port on the Walkera Devo 10 without any modifications or aircraft setup. I whipped up a cable to power both from the same lipo battery. I'm told it will be stable to five miles out, which is all I could safely expect from the Discovery's 4S battery. I was also told a tracker is a wasted effort, which is disappointing because they look so kewl. The new video antenna is a helical with 7.5 gain from videoaerialsystems.com. Because nobody seems to have left hand polarity antennas, I had to replace the transmitter antenna too, with another mushroom. So the experiments continue.
11-5-2014: Got an LC Meter from Amazon.com, which comes with absolutely no instructions. Metered all the DJI motors I have, and put the best ones on Christine, and the others on Gidget. Three of the motors on Christine were much worse than some of the spares. The wiring on these motors looks very crude, wonder if they were re-wound by hand. Having a third-hand thing is absolutely necessary for soldering wires to connectors. Got a servo tester from Hobby King to run the motors up with on the bench, in order to listen to them under load at full throttle and measure their temps. Got a tachometer to determine if they're all spinning the same speed, not sure if it matters at idle. Seem to have trouble finding the right motor clips and thrust washers. Maybe I should just buy new motors instead, they worry me more than the flight controller. Securitycamera2000.com sent me the wrong camera, a black and white model. We chatted, and they asked me to send pics of the OSD menus in the camera. Done. Now nothing. Did they send the color camera? I'll wait a while longer to nag them again. This is the first order from China that had a problem. Flew the company Phantom 2 towing a hospital bedsheet (fullsize) as a test banner. Slipping a thin wood dowell inside the seam keeps it flat and legible. It flew controllably in 10 mph wind. Found out the battery in the Phantom is a 3S, how do they get 20 minutes of flight out of that?
10-30-2014: After Christine fainted on the 19th over a four lane boulevard, I decided to check her out more carefully. Click Here for the log. Think a transmitter battery connection problem caused this. Rewired the video / OSD / camera system direct to the flight battery. Got the pocket DVR from Hobby King, so I can go back and watch the fatal error over and over. Just ordered an LC Meter to check the motors for internal shorts, and I'm going to order the right crimpers for those tiny micro blade connectors. A patch antenna, tracker, and Immersion diversity receiver are on the wish list also. Finally, I'm beginning to think people were right about goggles. I can't see much around the edges, like the battery or satellite count. Thinking about screens. Problem juggling glasses and goggles also. The prescription lenses make it worse, as I read elsewhere.All this sounds expensive, but it's really not. It's great to be learning about new technology, at least to me. It's a lot like when I started with computers in the early 80's. But my Apple II never game me a blast of adrenalin when the screen suddenly goes blank.It's going to rain Saturday, so I'll probably fly again Sunday.
10-15-2014: Pretty good flight over the weekend. Below is the intersection of Woodley and Burbank Blvd. The long trip was .6 miles each way. Awaiting a 600mw Immersion video transmitter, and some instruments to test the motors and esc's. The pilot camera for Gidget seems to be stuck somewhere in China. Gidget gets the Fatshark video transmitter from Christine. There's a link on the left to my Flytrex profile.
10-6-2014: Top is Christine, bottom is Gidget, in construction.
After buying a better soldering station I took Gidget apart again, to re-solder the connections. I'm going to solder the motor wires also to eliminate another point of failure. The radio tests OK, and three of the motors appear to be OK. Looking at a Pixhawk controller for fully autonomous missions. Hoping to get a 600mw video transmitter for Christine this week. Didn't do any flying this weekend, too windy in the hills.
10-3-2014: I think Christine needs a longer range video transmitter, like the Immersion 600mw unit for around $90.Bought a smaller, lighter battery for the FPV system, and put the original one in the transmitter.
9-27-2014: I really went nuts, and bought a used TBS Discovery. This is the model I really wanted. It came with a Devo 10 radio / receiver, and LED light strips on the arms. I added the Fatshark Predator FPV camera and transmitter, and a Flytrex Core flight data recorder. My flights can be seen Here
. On the first flight it disappeared for five minutes. I took my eyes off it for a second to put the goggles on, and it was gone. As I started searching the weeds it returned and started landing itself. I named her Christine 'cause she has a mind of her own. I bought new 4s batteries, and installed an alarm I can switch on to help find her in the weeds. I set the transmitter up like the Phantom I'm familiar with, so the throttle springs back to hover position when hands are off. I also added a low-battery alarm on the separate video transmitter battery, which I moved further forward for balance. I'm just using the board camera, not a GoPro. Learning something new every day, lotsa fun. Will add some pics.
8-1-2014: I have a new hobby, flying the DJI Phantom 2 quadcopter. After several horrible experiences with radio control I was not interested in playing with those again. But my friend bought one to advertise his business at occasional events, by lofting a banner. He always has "innovative" promotional ideas. I was appointed to fly it, so I started watching youtube videos and reading websites to get familiar with it, and took it to the local RC airport. We bought one without a camera, to maximize the payload it could carry. It's extremely easy to fly, self-leveling and holds it's position with a compass and GPS satellite navigation. There are many videos of them flying away out of control, but that hasn't happened yet. I keep a log, just like a pilot, of flights and aircraft work. I'm also careful to fly it away from trees, buildings or people. I tried to buy liability insurance, but so far nobody will accept the risk. I would like to fly it more often, but I only go on weekends early, before the wind develops. The first flight with the banner attached was fine, till a breeze dragged it away and down. It wasn't damaged much by the hard landing,and flew again a few minutes later with a new prop, and without the banner. Eventually I'd like to add cameras and the on-screen flight data, allowing me to see what it does, fly it out of sight, and perhaps even at night. DJI makes larger, more expensive copters also. I'm also interested in the TBS Discovery, which uses the same "autopilot" flight controller.