3689456980?profile=originalSo my buddy Shad and I headed out to my flying spot to fly the Skywalker.

This time around I used my new roof-top antenna mount, with VTR and Planner PC mounted inside the SUV in the back seat.  I found a mount designed for an iPad which worked to hold the ASUS tablet behind the passenger seat headrest.  Worked perfectly. 3689456935?profile=original I set the VTR on the console between the driver seat and passenger seat with the screen tilted so that I could see the video output.  3689457007?profile=originalWhile I have two video cameras sending video to the transmitter, I haven't yet recieved my video switch, not have I cracked exactly how to activate the switch, so I just hard wired the side looking camera in to see how mounting angle and field of view were.  Besides, the idea is to record the forward view in HD with the Contour camera, right?

Before we left for the field I also finished up my pre-flight checklist.  I have a terrible memory, and have forgotten to complete important steps before flight before (set home) so I wanted to establish a more repeatable procedure.

Once at the site we got all setup, mounted the antennas and pre-flighted.  Of course, my memory being what it is, I forgot to use the checklist.  Well, we used the checklist, but actually just to stabilize the wing of the plane as we calibrated the gyro...  I'm a knucklehead.

During the pre-flight, all was good except that when in FBW-A and STAB modes the lelevator seemed to have very very little control authority.  The servo pitch gain (P) was set to 300. Thats higher than the what others seem to be using, but I doubled it to 600... it was an improvement though still provided less deflection that the other surfaces seemed to have.  I need to look at the control horns and servo arm to see if perhaps I have set it up improperly.

After a brief mis-start Shad launched the plane and started recording with his iPhone.  I remembered this time to start the VTR to capture video from the flight... but although I turned the ContourHD camera on, I entirely forgot to set it to "record".  Crap.

So this time I was able get the plane into the air and gain altitude. I flew for 2-3 minutes, initially on manual then in FBW-A and STAB.  All worked very well, though the wind picked up and I was seeing some effects on the plane.  Once I was confident, I threw the switch to auto and the APM took over.  I was very happy, it flw in a very stable manner.  I had defined a very basic square shaped course.  3689457034?profile=originalI'm not sure that I'd say it followed the course, I'm still looking at the log data, having trouble developing an overlay so that I can see it output on google earth.  The telemetry data is showing me history that doesn't strongly suggest the waypoints were followed.  I seem to have lost telemetry at a certain point prior to "landing" as the kml terminates way prior to the "landing".  I'll post those files.

When the plane was at it's furthest point, I got worried that it was wandering off out of control, so I started nudging it home. Things were ok for a bit, then I noticed I was having less influence, it wasn't responding well to the TX.    Then shortly thereafter it started heading in, in a spin.  I gave it full up-elev, but it dropped below bush-tree level and that was it. 

Shad and I identified an azimuth to the plane and hopped into the SUV and drove over the the site - or tried to.   The terrain was too dense with bushes, we tried for 45 minutes or so to get to the site without scratching the hell out of the SUV, but couldn't find it , even after dismounting and seraching on foot.  The telemetry had halted and I didn't trust the indicated last position.  I haven't been able to build a kmz using the logs pulled from the APM, just from the tlogs.  I'm actively working this - any help????3689456944?profile=original

We ended up heading back to the launch site, regained the azimuth to the "landing" site and started walking.  Found the plane just a few minutes later, we had been searching in the right direction, but too far from launch.3689456980?profile=original

The plane was in surprisingly good shape when we found it. I would never have believed it.  I was able to identify the impact point (below). It hit the ground somewhat hard, but was upright, wings level and could not have had more that a 15 degree nose down attitude.3689457041?profile=original

The wooden camera pod was damaged, more from the CountourHD (not recording) being popped from it's mounts and the safety wire shearing through the wooden from. 3689457168?profile=original 3689457056?profile=originalThe telemetry unit looks to be toast.  The high mass of the 900mHz antenna wrenched the RP-SMA connector off the circuit board.  I think it is repairable, but not by me.  I'm seriously considering dropping the whip antenna and picking up a 900mHz cloverleaf antenna from ReadyMadeRC.com.  I've very happy with the 1.3GHz cloverleafe I use for video.3689457184?profile=originalI'll give it a shot at resoldering, but I'll have to do the work under a microscope and I think I'll have one shot at it.  That was a shame, of all the parts of this plane, the XBee's have been the most difficult to get.  I finally gave up on 3DR and bought directly from Digikey.  Maybe this is a good excuse to go with the new 3DR radios...

The vertical stab is torn a bit, but thats an easy fix.3689457201?profile=original

Overall, after only 6 minutes of flight I'm still very happy to have another success.  Every time I have flown, even for the shortest flights, I have learned something.  I'm a big believer of lessons learned. 

I still haven't been able to download the video from the VTR, I have no Firewire capability, gotta get an adapter.  When Shad sends me the iPhone vid I'll edit and post.

Here's the YouTube video...


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  • Developer

    Go for the 3DR they are great and have less interference to GPS, I have to keep Xbee Pro 900 6" away from Ublox. 3DR have adjustable power out for range testing.

  • @Mike


    So far the 3DR radios have been plug and play for me. Definitely less effort to set up than XBees and theyre advertised as not bricking and so far thats been true for me. I think its an upgrade but not necessarily worth throwing out a working XBee set for.

  • Mike Another reason I was sending you and your buddy over to get to know the guys at the FSS is because that is where all the local pilots that have planes hang out You are doing really interesting  stuff any body that owns a plane loves planes even RC  I admire what you are doing so will they get to know them they will take you and your buddy flying .and even come by and watch your flight tests Have a good day!


  • John,

    Im still going to try to fix the XBee.  Looking at it under a microscope there appears to be no damage other than the lifted pads.  I'll give it a shot, but intened to replace it anyways.

    How easy are the new 3DR radios to use?  I love the price but don't want to find myself jumping through too many hoops to get them to work.  It seems that, usually, lower price equates to more effort on these sorts of projects.

  • Burt,

    I haven't had the same issue with inability to retain satellites.  If anything, I was a bit concerned that my latest cold boot took quite a while to go 3D.  I attributed that to indoor startup and possibly the need to download recent ephemeris data, or a combination of the two.

    The data plotted on the blog is strictly tlog data received via telemetry.  I have downloaded the native log from the APM, have been able to plot it using the Planner plot feature, but have been unable to export it to a kml file for easy display on Google Earth.  In fact, the google earth display utility for viewing the tlog kml has taken me a while to understand and use effectively.  I might have to update my Google Earth.

    I'm looking for a good way to access that native log data.

  • Carl,

    I live very close to 3 different airports (KPHX, KSDL, KDVT).  It never occurred to me to ask for weather info.  Sounds like a very good risk reduction approach.


    As for the waypoints I set, I've been using square shaped courses in my HIL testing (XPlane) to work the PIDs.  Almost all of my testing has been with zero wind or other inclement weather.  I have turned up the wind, but mainly to show that the airplane will still stay in the air, not so much to demonstrate it's ability to navigate the waypoints.  I'll build an alternate course that willl be easier to navigate in wind, thanks for the input.

  • I had a similar break on my aerial XBee modem. I was using the whip antenna and the plane rolled over on a landing and broke the RPSMA connector. I wasnt able to repair it and ended up switching to the 3DR radios. The smaller size of the 3DR radios made it easier to mount the modems and antennas in a was that protected the connector better.

  • Mike

    The flight data, was it from the Mission planner and the xbee? Did you download the logs from the APM?

    I had a few flights that I too lost temeltry from the xbee, but still had data from the AMP. in my case the xbee bricked in the air, used to happen all the time, but in the last six months it only happened once.

    I fly on the west side of the valley from you, and looks like my system is working good enough to start to just fly out in the desert. I still have yet to find my range limits. At 3800ft I still have a good video, and LRS radio control that I still need to find the range of.

    The one problem I had last week, that maybe you might have had, was NO gps. Had 7 sats on takeoff, but dropped to 0 and I never got any sats back, found out on a RTL command, and plane just flew past me heading for phoenix, back to manual, and land, but never found a reason for it. This weekend didn't have a problem, and it flew the best missions yet.

  • I don't know how far you live from a major air port or an air traffic control center if not to far drop by for a visit at the 

    FSS  ( Flight service station ) (bring your buddy but not to many people )and get your weather from the flight coordinator bring him a coffee from time to time  tell him what you are doing and every time you plan a flight or went flying stop by or call him up and become friends. Since you are a pilot  you will be treated just the same as if you are flying a 747 (When I am driving my car I brake for birds!) You can down load all the weather in the world . but the guy at the FSS knows what is happening and going to happen right there Right now ! I know from flying big planes a 90 degree turn right over the way point doesn't work  you should cut across the corner at no more than a 45 degree angle  to intercept the next heading 3  30 degree turns are even better   you could add  two way points   one just before the corner one  after the corner when the plane reaches the first way point it turns 45 degrees  straightens up 30 seconds later reaches the other way point turns 45 degrees on to the new heading  on a big plane with no traffic and DME (Distance measuring Equipment ) at 400 knots it is common to cut across the corner to the next heading 20 miles or more from the way point. another thing you can try when you get it all back together is plan a  short course flight fhat is within sight get your buddy to Cary the plane around the course to the different way points on the ground and see what kind of readings you get  I know you are right into it Good Luck!


  • Mike,

    You're probably right about the elevator servo.  Seeing that the servo arm is pretty neutral in its position and that the nose isn't all bashed up I'd have to agree that the plane came in pretty shallow.

    Good luck with flight #5!



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