Getting back to normal

Well, this is just a post to say that things are getting back to normal after the great fuel disaster of 2016. We put in 2 new tanks and, what do you know, one of them had a hole in it. So now we have that taken care of and seem to be holding fuel.

So with all that sorted, we turned our attention to getting all the avionics back in place. It took quite a while as the companion computer and SSD threw off the layout of the avionics tray, but everything is pretty much in order.

Why yes, that is a 4-port USB 3.0 hub. Your drone doesn't have one of those?

And Patrick got the payload tray pretty much squared away. Now we just have to sort out the mounting/vibration damping part.

I'm still planning to write that tutorial on the companion computer setup, hopefully I'll have time to work on it later this week.

Mugin Updates

Well, it is about time for some more updates on the Mugin. I'll try to go point by point with what has changed since the last post.

The biggest news is that it has flown! We have done a few hours of flight testing including auto flight and everything seems to be working well. With that vibration damped avionics tray seen earlier, there is actually less vibration reaching the IMU on this aircraft than on our electric planes... We have done some early testing on fuel burn and the results have been a little disappointing, but we are re-tuning the fuel injection and may get a little better performance out of it. As it stands, I think we will get ~3-4 hours of flight time. With proper flight planning that shouldn't actually be much of an issue. And, flying longer than that means our 256GB SD cards for the A7ii won't be big enough and we'll have to find another way to store the images.

Waiting to fly

A little photo shoot

Now, some bad-ish news. A pinhole leak somehow found its way through the plane over last weekend. We discovered it on Tuesday when we pulled the canopy off and found the fuselage filled with about half an inch of fuel and all the printed plastic parts melted into goo. Thankfully, no electronics appear to have been damaged as they were all mounted on their elevated platforms. After a couple days of brainstorming, I ordered a pair of the 100oz tanks we use in Mugin 1.0. It isn't the perfect solution but it will get us flying until I come up with something better. I'm thinking maybe a custom aluminum tank...

We didn't get any pictures before this point, we were rushing to get everything out of the fuel

Goo

Stripped bare

The good thing that came of this is that it forced us to strip the aircraft down to the airframe and start anew. That means we were able to go back and rewire and clean some things up that we probably would not have bothered with otherwise.

Pretty wiring

More pretty wiring

A beautifully designed JST power distribution block

So all in all, it wasn't all that bad. I'm just glad we didn't have that fuel leak down in Peru...

Ok, on to other things. The alternator and power system arrived a couple weeks ago. There were some fitment issues and growing pains but it is all installed now and it works flawlessly. It provides clean 7 and 12V supplies to the aircraft that are backed by the alternator, battery backup, and a shore power connection.

That alternator sure does look good... It almost looks like a big brushless motor (which, I suppose, is precisely what it is)

The first motor test with the alternator installed.

Also, we have done some testing with the new IP radios, including range testing. With the 23 dBi antenna and the amplifiers we were able to get a mediocre link at 85 km. We have ordered a 30 dBi dish that should give us the mythical 100 km, or at least get us close. Hopefully we will have that soon so we can get back to range testing. In the picture above, you can see the amplifier mounted fore of the avionics stack. And, I'm also about to get to work on the antenna tracker. Version 1 wasn't robust enough so we go a Yaesu G-5500, which is way overkill but will do the job. I just have to build some control circuitry for it and interface it with the Pixhawk.

Finally, a teaser. I've been working on a companion computer to simplify the electronics inside the aircraft and provide us with some computational horsepower if we every have applications that need it. Using an oDroid XU-4, the core functionality is:

• Forward Pixhawk Mavlink stream over the IP network to the ground station(s)
• Pull images from the Micasense RedEdge and save them to an SSD
• Stream video from the nose camera over the IP network

All of these functions have been bench tested and are working. I expect a couple issues will pop up when I install the system in the aircraft but it shouldn't be too bad. The video is great, with only about 0.5 second lag and great quality (especially considering I've limited the bitrate to 1 Mbps). In addition to these 3 functions, we have a few more that will be forthcoming:

• Data logger function for (non-avionics) sensors
• Payload control
• Forwarding of auxiliary telemetry (motor health, fuel level, etc)
• Saving data from RGB camera (maybe Sony, maybe something else)
• More?

I hope to soon be putting together a tutorial on how to implement those 3 core functions on the XU-4 as there isn't a good one yet. Further companion computer discussion will have to be saved until then. I have waxed on long enough. 

Part 107 and more

Well, it's official, today I passed the 107 test. I did pretty well on it, although I was aiming for over 90 and fell just short. All in all, I thought it was an excellent test that will ensure that yahoos who buy a Phantom on Amazon can't go out and sell their services while endangering the public, or at least not legally. It isn't easy, but that is a good thing as it will absolutely advance the industry and start to build the credibility we deserve.

If you're looking for some insider info, I'll provide a few pointers:

1. Know. Your. Charts. Charts are a HUGE part of the test. My estimate is that they comprised about half the test. I thought I was pretty squared away on sectionals but I still missed 3 or so questions on them. You will need to be able to interpret charts to answer multi-level questions. Further, you will be expected to understand the 107 regulations and determine what is and is not allowed in complex airspace delineated on charts.

2. Know the more obscure parts of 107. Of course you should know that you're limited to daylight operations (or civil twilight with anti-collision lights visible for 3 SM), 87 kts, 400' AGL, 3 SM visibility, 500' vertical and 2000' horizontal cloud separation, etc. But you will also be asked about the non-operational aspects of the rule, too. Be sure you know accident reporting requirements, registration rules, rules about your airman certificate (once you have it), etc. You will have multiple questions on these non-operational aspects of 107.

3. Understand performance. This material isn't inherently more difficult than the rest, but it is easy to get confused, especially if you aren't already familiar with the physics behind how an airplane flies. Know how CG affects performance. Know how loading, including dynamic loads (i.e. turns) affect performance. And know the difference between pressure and density altitude as well as their effects of performance.

Well, that is it for my 107 advice. Now for a couple quick updates on the Mugin. The biggest thing is that I've been working on getting wiring installed and mounting up all the electronics. The wiring isn't looking quite as clean as I was hoping but it isn't bad. Once it is all said and done I think I can make it look pretty nice.

White 3D-printed blocks are epoxied to the fuselage structure and small carbon plates are permanently mounted to those blocks. Vibration isolators then attach the avionics stack. It is hard to see here but the Pixhawk is mounted bottom center, the Piksi is bottom left, Dragonlink bottom right, and Powerbox is on top. Microhard radio will be mounted beside the Powerbox once I get a functional case printed.

The avionics stack will hold everything you see above plus the Microhard radio. The radio amplifier, PMU, and backup battery will be mounted just behind the nose gear. I'm planning to rail mount them so they're adjustable for CG.

Also, I fully assembled the plane to show off and got some pics of it with v1.

The fleet looks nice, doesn't it?

Well, thats it for now. Look for another update in a few more days once some more electronics are in (and hopefully servo linkages for the flaps are here).

Mugin Updates

Here is the latest on the Mugin and a few other updates. First of all, I got the fancy fuel-injected motor mounted to the bench, ran it, and then got it mounted on the plane. That is one big step toward a maiden. Also, it is insanely powerful, as compared to the Saito FG-57, so this plane will have much better climb performance, payload capacity, and ability to fly at high altitude.

Servos are all in and wired up. I still need to make the wiring harness for the fuselage but I'm taking it slow until I get all the electronics mounted in their final locations. And, speaking of, I just finished the custom vibration-damped avionics stack. Hopefully it does its job and doesn't end up amplifying vibration...

All the parts are in except for the alternator and radio amplifiers. Hopfully those will be in soon so we have everything we need. In the meantime, I'm going to finish up getting the electronics we have mounted and wired in. Also, I got around to powering up our Micasense RedEdge today. It is an impressive little camera and it took me no time to get it triggering off the Pixhawk. It is really configurable, which is nice. It means that on the Drak we can simply pull out the QX-1, unplug the trigger from the servo wire, plug the RedEdge into said servo wire, and we're ready to roll.

The other major thing I'm working on is an accuracy comparison of DroneDeploy, Photoscan, and Pix4D. I'm using the campus imagery from 2 years ago, which isn't the best dataset, but it is at least a real-world example. I have a CAD file for the entire campus so I'll be measuring points in it and comparing to their position in the imagery and elevation in the DEM.

There's bound to be some kind of mischief I can get into having all this information...

Well, that's it for now, I'll update in a week or so, hopefully with a nearly-ready-to-fly plane.

The latest from the Skunk Works

Well, it has been quite a while since the last time I posted on here, huh? It looks like the last time I was posting about endurance quads. Well, I still hate quads but we do have some updates since then.

First of all,  the more mundane stuff. We have a fully functional Ritewing Drak. I built one earlier this year for a client and since then the lab has picked one up. It is a really excellent platform that carries more payload, faster, longer than a Z3. It is basically better in every way. The only downside is that it is significantly bigger (1.5 vs 1.2 m wingspan). Here is a picture:

This isn't actually ours, this is the one I built for a client and currently resides in Canada. But you get the idea.

Ok, now on to the really exciting stuff. We are gearing up for another campaign in Peru but, this time, it won't be with any anemic little electric plane. We are building V2.0 of the 3m Mugin and it is shaping up to be pretty incredible. A lot is different from the first, including the airframe. The newest version of the Mugin airframe has a lot of improvements including, but not limited to:

• Carbon fiber fuselage frame (formerly wood)
• Thicker fiberglass fuselage skin
• Fiberglass wing and tail skin (formerly wood)
• Improved fuel tank (so we might not be throwing this one away immediately)
• Beefier main landing gear (unfortunately still the same crappy nose gear)
• Flaps! (split flaps, at that)
• H-tail providing redundant elevator and rudder

And then there are the improvements I'm making to the guts. Again, including but not limited to:

• DA70 motor modified by HFE International for fuel injection
• Sullivan UAV 300W alternator and power module
• Microhard pDDL broadband data links (for telemetry and video)
• TriadRF RF amplifiers (to boost that pDDL and get us 100km range with the help of...)
• Actively tracked 23 dB parabolic grid antenna on the ground
• All around better avionics mounting, layout, wiring, etc and a variety of custom 3D-printed mounts for different bits and pieces

So, it is shaping up to be pretty exciting. I've put some picture below to show off the goods and I'll post again sometime soon(er than last time).

Thats one helluva antenna

V2, with V1's fuselage in the background

Mmmm, redundancy

Love me some EFI

Enduroquad Success

2 EnduroQuads ready to take flight. Both carry 20 Ahr of 4S. Ours, on the left, has a Tarot 2-axis GoPro gimbal as payload and the one on the right has a 6600 mAhr 4S standing in for a Sony a5100.

Well, as I mentioned in my Vibration Consideration post, I have been working on new iterations of an endurance quadcopter. Today I cleared the final hurdle in declaring it ready for use: I flew it in Auto. As I mentioned before, I have seen this quad (and others) descend in forward flight while in Loiter or Alt Hold, so I was a little worried about how auto would go. The only thing to do, though, was to give it a shot. So, I gave it a plan to fly a grid over Davis Field and let it rip. It was basically flawless. After it finished and began loitering at the final WP, I restarted the mission, and let it go again. Then I put it in RTL and let it autoland. Finally I restarted the mission, took off in Loiter, switched to Auto, let it run, and then did an RTL and autoland again. All in all, it was really nice with no significant altitude loss at a 6 m/s cruise.

Screenshot showing 3 auto flights using the same flight plan. Note the excellent agreement between all flights (orange, green, and pink)

Here are my more detailed notes:

• Upping rate_yaw_P to a the healthy value of 0.28 (from a default of 0.2 and above the "maximum" value of 0.25) fixed the issue I had with the nose wandering around. I'll say, this behemoth needs some huge PID values to make it fly well.
• I did observe altitude drop at the end of transects which is well known to the APM community. This seems to be a physical barometric pressure issue and there doesn't really seem to be a workable fix for it. I have never seen it present a problem, though, as it has always been a controlled loss of about 1-2m altitude which is then regained.
• Copter 3.2.1 doesn't like to land on a slope. In both autolandings I had to switch to Stabilize with the throttle down as the landing detector didn't kick in with the slope there. The changelog indicates that this may have been fixed in 3.3 (they added "improved landing on slopes"). I will find out when I test the bigger EnduroQuad which has 3.3. I will also likely upgrade this one to 3.3
• Takeoff in Loiter is quite nice. The devs have done a considerable amount of work with this in recent releases and I now find it to be a less dramatic way to get out of ground effect than punching the throttle in Stabilize.

So, that is pretty much it. My plan for the rest of the week is to get a few more hours of time on our quad and get a few Auto flights in on the bigger quad to convince myself that they are both 100% mission capable. Then it will be on to all sorts of fun projects like using TIR imagery to census lions, tigers, and bears at the NC Zoo and deer at Pilot Mountain. We are also planning to use it to identify energy leaks on some buildings around campus.

Good to be productive

I have been hating on mutlirotors quite a bit lately, and for good reason. Our planes are easy; they work every single time we need them to and they do exactly what we need. They are easy to set up, easy to use, and they get results. Multirotors, on the other hand, tend to be a huge pain to get operational as they are super sensitive to vibration (see my earlier post on this topic) and when they fail they tend to fall out of the sky. I basically have felt like I was spinning my wheels for the past few weeks with the multirotors.

The past couple days, though, I made a lot of progress. First I figured out the vibration and altitude hold problem I had been having. That got alt hold and loiter working quite well.

Today I maidened a second endurance quad with larger motors for carrying a Sony a5100 and gimbal. After a little tuning it flew really incredibly. I think I have as much confidence in it's stabilize performance as any other copter I've flown. It hovers at just under half throttle, it has tons of power, and it flies like its on rails.

I also did some testing with the Swift Navigation Piksi RTK GPS system, which will go on the heavy lift endurance quad. The first thing I noticed is that it is insanely simple to use. For basic positioning you simply connect both Piksis to telemetry radios, power them up, and connect to one over USB or serial. Then you wait 10-20 minutes for it to get an RTK lock and at that point you get centimeter accurate relative position precision. I wanted to verify that advertised accuracy so I measured the distance between the antennas and compared it with the distance reported by the software. I was amazed, the RTK distance varied within +/- 2 cm of the measured distance. I haven't installed it on an aircraft yet but I'll report back in when I do.

With all that good news, I did have a couple problems today. First, Enduroquad 1 had a very odd issue in flight. The controls were all delayed by about a second and changed in a stepwise manner, making it quite hard to get back on the ground safely. I would give input, it would come into effect after about 0.5-1 seconds, stay at that input for about a second, then update to whatever input I was giving at that point. I gave up on troubleshooting it in the field but when I got back to the shop I determined that the Dragonlink was at fault. I had upgraded to a new transmitter and it turns out it has a new firmware version. Even though I fixed it, this does seem to be a significant safety issue to me, as firmware versions should either be compatible or not. There should never be a case where the RC system only partially works. I might report it as a big to Dragonlink but I doubt they would do anything about it...

The other issue I'm having is that both quads are losing 1-3 m of altitude during fast forward flight in loiter or alt hold. I had observed this behavior before and thought it was an air pressure issue. So I used my lessons learned finding vibration and did the same for this. Here is what I found:

Here we have pitch in yellow, target altitude in green, barometric altitude in pink, and calculated altitude in red. When you see sustained positive or negative pitch that means the copter is in forward flight. As speed builds, you see a lot of noise in the barometer and a gradually increasing calculated altitude as the barometric variations slowly cause deviation from the accelerometer readings. Then when the copter stops you see that altitude plummet, as the copter has actually descended but doesn't know it until forward flight stops. Then you get the gradual return to target altitude. The noisiness of the barometer signal makes me pretty confident that this problem will be solved but putting a cover over the pixhawk to hopefully prevent airflow around it and only allow real pressure changes. We will see how that works out tomorrow...

Now What?

I'm excited to announce that the Huffington Post/AOL documentary series, Now What with Ryan Duffy, made an episode about our work in Peru. The episode is now live, check it out:

Now What with Ryan Duffy

Vibration Consideration

Ok, so I fully realize that we have been absolutely awful about updating this thing. The other day, as I sent email #5832 to the flight crew updating them on progress with our aircraft, I remembered that avoiding having all of our development information hidden away in email threads is exactly why we created this blog. So, with that in mind, I'm going to try to do a better job. I may also set up a Gmail group, as that seems like a really good way to track/organize routine/mundane communications within the group that don't really justify a blog post.

Anyway, the big news items are:

• The Mugin is flying beautifully in manual and FBW. We haven't tried auto, but will like do that the next time we fly. I'm still concerned about vibration but FBW at least seems to be totally unaffected by it. An FBWB test may be in order
• The Z3 is still excellent. 60% of the time it works all the time.
• My company built 2 Skywalker X8 aircraft for a client and they are really superb machines. They are a little flimsy, but the trade-off you get for that flimsiness is huge: carrying a Nex-5 for 75-90 minutes at 18 m/s. We need to buy 1 or 5. 
• I am building a quad for a client which will have the Swift Nav Piksi on it. I am excited to see how well that performs.

And now, on to what I want to spend this post talking about. I've been developing a new quadcopter which should fall nicely into a niche of good endurance combined with high portability. Spurred on by the excellent work done by the Ecosynth crew and Jonathan Dandois down at the STRI in developing  a quadcopter with 50 minute endurance from spare MK parts, I set out to copy it. I believe this is detailed in an earlier post on here.

Flying Low

We have talked about the potential need to fly from a higher elevation to a lower elevation using Pixhawk Auto mode.  I have seen the terrain following and absolute altitude discussions but never could I find a discussion on making an auto mission using negative altitudes.  Well that changed today:

I setup two flights starting at 10 m and descending to -10 m at the end of the grid.  It work perfectly!!!  The only changes I made were were to set the Alt Warning in the wp list window to -15 m.  I was losing telemetry (3DR radio) connection on the return legs and I should have raised the antenna.  

Now we need to combine this with a laser altitude unit....

Next stop, Belize!

Well, today has been a pretty good day so far. I was up late last night working on resolving all the dependencies for Ecosynth to run on RedHat/CentOS. I got it to compile and today I will find out if it actually works. I also got a fan controller for Big Deac so now it sounds less like a vacuum and more like one of those little white noise generator's outside of your therapist's office.

The bigger news, though, is that our newest aircraft made its maiden flight this morning.

The newest Zephyr in the fleet, complete with a wonderful looking black and gold Monokote livery

The plane is a Zephyr 3, like the others, but is setup somewhat differently. Instead of the Ritewing secret sauce motor we have a Turnigy 3420 1250KV driven by a secret sauce ESC. Elevons are controlled by Hitec HS-5245MG servos. This setup provides boatloads of power and good control. FBW settings from the other Z3s are a little sluggish on this one but thats nothing a little tuning can't fix. Finally, you'll notice the Ritewing GoPro and FPV camera box on the nose. This is nice as it will allow us to run a GoPro for video recording and a more reliable FPV camera for the live feed.

So, now it is off to start getting gear ready for the trip to Belize; departure is bright and early Friday.

Big Deac is a little bigger

Well, the title says it all. It came to my attention a couple weeks ago that Intel's Xeon Phi 31S1P coprocessor is on sale for less than $200. The Phi line is out to compete with nVidia Tesla in the HPC market but despite looking similar it has some critical differences. The biggest is that while a Tesla is a high-end graphics card with firmware designed for for HPC, the Phi is a highly-parallel Xeon processor (57 cores at 1.1 GHz, in our case). This means that while it isn't as parallelized as a GPU, it runs an (almost) full x86 architecture. While that should make it easier to program for, in our case it is unimportant. In fact, in our application it should be significantly inferior to a Tesla, or even a top of the line desktop GPU, but it is only $200. So, we got one to see how it goes.

The card, in all of its glory. As you can see, it is quite a behemoth. It is about the same size as our AMD Radeon 7970 and is, actually, a little thinner.

Another difference from the Tesla cards is that the Phi can (currently) only run on Linux. And, to make matters worse, it only natively supports RHEL and SUSE. Being the cheapskate that I am, I had no plans of investing in enterprise Linux. Instead I opted for Ubuntu 14.04. I found this excellent guide on how to get it up and running. I did have some difficulties getting it going but, for the most part, everything went as planned. Following the instructions closely you shouldn't have a problem. My only addition is that when you download the OpenCL drivers, get the ones that say they are for RHEL/SUSE. Even though they say Ubuntu isn't supported (and there is an Ubuntu version which lacks Phi support), the OpenCL 15.1 Runtime for Linux installs perfectly fine on Ubuntu.

The next (ongoing) challenge was cooling. The card is passively cooled and designed to be installed in a server with what amounts to a wind tunnel in it. So, to satisfy the cooling requirements of the card (a whopping 275W TDP, to be exact), I made my own wind tunnel. I put a 75 CFM intake fan in the front of our case and a 150 CFM 92 mm fan on the back with a, erm, custom ducting unit, to draw air through the heatsink of the card.

The exhaust fan. It is LOUD.

The card installed. Not shown is the 120mm fan now installed below the HDD bays to push air toward the intake side of the card's heatsink.

The exhaust fan is very, very loud (who knew pushing 150 CFM through a 92 mm diameter hole would be noisy), but it keeps the card running nice and cool (currently peaking at 52 C to be exact, which is well within spec).

So, with everything in place, it was time to fire up Photoscan and give it a whirl. To my relief the Phi and the 7970 both showed up in the OpenCL menu in Photoscan, so I selected them and got to work. I opened our 3000 image campus dataset, deleted the dense cloud, and set it loose reconstructing the whole thing on medium quality. It is looking like it will take about an hour and 45 minutes (a very respectable time) and isn't even able to fully utilize the Phi (not necessarily a good thing). I think chunking tasks and running them in separate instances of Photoscan will give further performance gains. Once it is done I will go in, disable the Phi, and see how long it takes then. But, for now, all is looking quite good.

Shortly after starting the reconstruction.

Pushing the limits

While I have, for some time now, hinted at our intentions to obtain a more capable aircraft which will provide longer endurance and higher payload capacity, I have kept it mostly in the shadows. Well, it is now time for me to [very excitedly] announce the arrival of the newest and most capable addition to our fleet of aircraft: the Mugin v3 aircraft.

This impressive aircraft will launch us into a whole new class of UAV remote sensing, giving us capabilities far beyond our current stable of electric aircraft. Here are some of the details:

Wingspan:	3m
Material:	Wood structure, fiberglass and film covering
Powerplant:	Saito FG-57TS 57cc, 4-stroke, twin-cylinder, gas engine
Propeller:	Xoar Beechwood 22x10
Flight controller:	3DR Pixhawk
Cruise speed:	120 km/h
Endurance (expected):	~5 hours
Range (radio limited):	~100 km

This aircraft is not widely used, but there are some notable exceptions. CanberraUAV used an earlier version of the aircraft in the 2012 Outback Challenge. There are a handful of others who are discussing using it with APM/Pixhawk or are in the process of adopting it into a program, but we are certainly spring-boarding ourselves to the forefront of this work.

Stay tuned for updates on the build and testing of the aircraft. At the moment I have done the little bit of assembly that is required on the fuselage, gotten the motor and fuel system set up, and installed all the electronics. The next steps are to break in and tune the engine and power up the electronics, configure them, and test them out. The it will be flying time. As I have been building I have been looking around and found that there is an utter dearth of information about this airframe, so I will do my best to document the process in painstaking detail.

Too much excitement

Alright, after long absence I have some updates to make. First of all, to follow up on my last post, the endurance quad got back-burnered but we're going to turn our attention back to it. We made some test flights and determined that the vibration levels were too high for reliable flight. I traced this issue back to the motors, so we're replacing them. We could change bearings and fix the vibration issue but I already wanted to swap the motors for some lower KV ones, so I decided to save the time on the bearing work and just get the right motors for the setup. They should arrive in the next week or so, so I'll update once we have some flight time on the aircraft.

2 Zephyrs heading to Peru soon

Second, I have been in a build frenzy around here, with 3 Zephyrs just getting finished up and another right in the middle of the build. I am also working on a rail launcher that should get the planes in the air more reliably. It looks like we will have some fantastic weather this weekend, so we should be able to get all those new aircraft up and see how they perform. I'll provide more info on that after the weekend.

The Deacon Zeph in its fantastic black and gold livery

A bit of bad news is that we did a test flight on one of the new Zephyrs a week ago and had a crash on takeoff. We had flown it before and it performed really well, so that caught us by surprise. The wind was quite gusty and swirling on the ground that day so we think there might have been a stall issue with a rogue gust on takeoff that put it in the ground. We should be able to determine if that was the issue this weekend. I review the logs and there was a suspect board voltage change, but it didn't happen until after impact. We'll keep an eye on that to see if we actually have a hardware issue.

Finally, on the same day we crashed the Zephyr, we also did our first ever successful fully automatic airplane flights. We had tried auto-takeoff before with a skywalker and it ended badly. We were hoping that new firmware had solved all the issues we had before, so I put together an auto takeoff, circuit, and auto landing mission on Marcus' Pixhawk-equipped Apprentice. We were able to carry out the flights with total success from hand launch and ground roll despite the heavy winds (really too windy for an Apprentice). We found the results to be repeatable, with identical performance on numerous flights.

Well, thats all for now, but hopefully on Monday I will have lots of exciting updates to report.

Endurance Quad

I have been talking with Jonathan Dandois (of Ecosynth and the Smithsonian Tropical Research Institute) about the work each of us has been doing lately, and he told me about a new aircraft they had. They have put together a long endurance quad using a modified MK Okto frame, MK motors, and 15" props and they got 53 minutes of flight time out of it. Hearing about that sort of impressive flight time pushed me over the edge, as I have wanted to put together an endurance quad for a while. It was made even sweeter by the fact that I had all the necessary parts in the hangar to make it a reality. So, 4 hours later, this is what we have:

Here she is, all ready to fly and only lacking props. I used the short arms from the Okto frame and added some strengthening to the frame where the other arms had been removed (they seemed to be structurally important to me).

In the interest of absolute minimum weight and maximum simplicity, I have simply attached a Canon SX260HS to the bottom of the battery cage.

The stack. I'm currently running a FrSky receiver but will probably switch to a Dragonlink after testing. An RFD900 sits on the back and HK F-20A ESCs drive the motors.

In the interest of minimizing weight I have used as few Deans and bullet connectors as possible, hard soldering most things in place. The motors have bullets but if things go well in testing I will probably go back and solder them.

As of right now it is ready for a test flight. I have configured the APM, gotten the transmitter set up, and have all the motors spinning the right way. Now all that is left is to get it airborne. Hopefully that will happen tomorrow. More soon.

The Final Countdown

Well, here it is, the home stretch. I'm currently back in Cusco after finishing up at CICRA and, sadly, retiring our old, trusty DAO. She had been through a lot and the foam at the rear of the fuselage was getting quite weak, which allowed the tail to move vertically quite a bit. I attribute it mainly to 3 weeks of daily rough landings, a 100m plunge into a stand of bamboo due to an in-air motor failure, and a failed takeoff which sent it tumbling over a cliff. So, all in all, it is pretty miraculous that she lasted as long as she did.

But anyway, it is time for the final chapter. On Monday I'll be heading back to Tres Cruces armed only with the hexacopter, my wits, and 2 compañeros from one of the universities here in Cusco. We will set of down the trail which is home to 8 of our tree plots, and we'll set up camp halfway down. We will use that as a base of operations to make daily trips out with the copter to image the plots and, potentially, some of the area surrounding the plots. When we're done the trail will spit us out at the other end, we'll catch a ride down the road a bit to San Pedro, and stay there for a night. The next day we'll head up to 2 more tree plots, image them, and hopefully head back to Cusco the same day.

That is if all goes well...

Needless to say I won't have internet on the trail, so check back in a week or so to see how it all went down.

Back to the grind

Well, as glamorous as seeking out illegal and environmentally destructive mining activity is, we have other missions which are just as important. Today we returned to our fundamental mission of mapping primary forest in order to be able to observe its current state and document change through time. Here is a look at this afternoon's flight path:

The 47.5 km flight lasted just under and hour and averaged 55 km/h flight speed. It covers just over 550 ha with an imaging height of 200-250 m AGL (depending on terrain). This flight will be combined with another, adjacent to it just to the north, to create a high resolution (<10 cm pixel size) mosaic of the majority of the area of the CICRA biological station. In addition to being useful in our own ecological research, this imagery will be available to others at CICRA to better inform them about the area in which they work.

ISR Part 2

We have more exciting news to report from the front line. As some of you may know, CLASlite is a deforestation detection software product developed by a team at the Carnegie Institution for Science at Stanford University. CLASlite uses sub-pixel analysis of Landsat imagery to detect small-scale deforestation such as artisanal gold mining and selective logging. The main limitation of CLASlite is that it is unable to identify the cause of deforestation, only that it is occurring. Thus, we need a system which allows us to classify the mode of deforestation at CLASlite hits and, specifically, to determine if it is natural or anthropogenic. While high-resolution satellite imagery can be used for this purpose, it is cost-prohibitive to obtain on a regular basis. We believe that drones are the perfect tool to address this need by flying to and investigating CLASlite deforestation hits. Today we tested that belief. Here is what we found:

Here you can see one of the mines we located using CLASlite guidance. At the top-center you can see active mining with the open pit, recently felled trees with leaves still on them, and a man operating a water cannon to wash away soil. Directly below that you can see the machine used to remove gold from the sediment and the tailings pile from the processing. At left you can see the pump used to provide the all important water floating atop a raft in a pond formed by an old mine.

It is not hard to fly over the forest here and find mining activity, but the way we found this site is special. We used the most recent CLASlite data, which identified deforestation which took place between June 23rd and August 10th, and used that to target our flights. Using this method we are able to locate new deforestation rapidly and readily identify its source. Here is a visualization of the process:

Red areas indicate deforestation detected by CLASlite in the 6/23/14-8/10/14 period

We then use the CLASlite hits to plan and execute a reconnaissance flight. This is the actual flight path from today.

In addition to the mining shown above, we also found other causes of deforestation. In one case we found agricultural activity and in another we found what appears to be a false CLASlite hit over a stand of young second-growth forest.

Using this method we can augment the impressive power of the CLASlite system by adding the ability to identify the cause of deforestation and provide continual monitoring of that area, if necessary. While our current aircraft has limited range, we intend to acquire larger, longer-range aircraft which can extend this powerful monitoring capability over vast portions of the Madre de Dios region under threat from ever-increasing gold mining activity.

Intelligence, Surveillance, Reconaissance

ISR. That is what our work is focused on here at CICRA. There is heavy gold mining activity in the area around the station and conservation concession and some of it has actually encroached into ACCA property. One of the major missions that drones will conduct here will be patrol to locate new mining activity around the station and the re-occupation of abandoned mines. This monitoring is vitally important to the rapid identification of mining activity so that it can be stopped before it causes too much destruction. This morning, during our first flight here at CICRA, we overflew and mapped old mines that have been closed. This patrol was conducted to see if miners had returned to the mines and reopened them illegally. Here is what we found:

In this photo evidence of active mining can be seen, including mats which the miners sleep on in the center, the machine used to extract gold from the sediments at left, and, we believe, the miners themselves just below the mats in the shade.

This information allows for an almost real time response to new mining activity and allows enforcement to be targeted at active areas without having to spend time patrolling for the mining activity. This is only the beginning of our work here at CICRA but it is a promising indication of what our aircraft will be capable of.

Mother of God

Greetings from the CICRA biological station on the Madre de Dios River. I wanted to take some time to write down what I plan to do over the next 8 days. The overarching goal of my time here is to provide training on the operation of drones (planes, specifically) to the staff here. They will be purchasing an aircraft similar to our Skywalker and will use it to patrol the station’s property. They will be looking for illegal mining encroachment, especially. The training I will provide, while covering the systems in depth on the ground, will also include quite a lot of time flying. We will make the best of the training flights by using them to image some important targets. Those targets include:

• Gold mines (both active and inactive)
• Tree plots
• Uncontacted indigenous populations

While these subjects are varied, they will allow us to answer a number of questions and hopefully provide a foundation on which we can continue to grow the program. Stay tuned to hear more about what we find and what it means. This morning we're off to do our first training flight which will overfly and map the illegal mining activity on ACCA property.