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Copyright 2007
Art Vanden Berg



High-Altitude Glider Mk II · Jun 20, 2005

Quite a few people have emailed to ask about progress on the “Mark II” glider. Well, here we go…

I set out to design this version in every respect using CAD software, as opposed to the previous version, which started mostly on paper. First, I researched possible payload requirements, whether scientific (ozone instruments, etc) or fun (DV cameras). Then, using a combination of spreadsheet-based optimizing, and a genetic algorithm that used flight simulation based on several thousand weather sonde profiles, I came up with the following airframe design:

Rhino3d Glider2

The improvements are many, so I won’t list them all here. The main ones are a more modular, far easier to set up airframe, with a completely separate payload tray. Rather than a dozen or more items to connect, there are just the wings, tail boom, and three pins to hold them in place.

Also, in keeping with the “always fighting the last war” tradition, this version is designed to be capable of transmitting a location even if it flies straight into a rock face at cruise speed.

The first step in producing a fiberglass shell is producing an initial male plug from which a female mold is then made. In this case, I used Rhino 3D to print about 40 sections of the body, scroll-sawed each section out of sheet pine, and then glued them together on a steel spine. Final shaping was done by hand, and checked against larger profile templates (didn’t have access to a 3D CNC machine 8-P ).

Assembled Airframe

As you can see, the first final airframe turned out pretty much exactly as intended. The first pull from the molds of a main pod, however, is a bit overweight; I used one too many layers of reinforcement. But I’ll stick with this prototype for the first few flights, and perhaps invest the two evenings it takes to make a new pod after the first few test flights.

The first payload package is to be a digital camera, and is being put together by Jeff Lydell. Should be pretty cool, as he’s generously risking a fairly good camera, and it will allow quick turnaround to web publishing and easy stitching together of panoramic photos.

The second payload package is a DV camcorder module currently being constructed by a fellow SFU physics geek, Robert Ramses. This is going to be something to look forward to, as he’s worked out a mirror arrangement to allow both forward and backward view transitions. Hopefully, we’ll get a view of the balloon release, flight, and parachute opening!

Autopilot

Autopilot2

The autopilot systems, in contrast, are less modular, and better integrated. This time, the system is micro-controller based rather than using PC-104 technology (I ditched the webcam, as it becomes too much of a design driver). The core microcontroller is a Microchip, Inc 18f6720, with 128k of program memory Flash plus an external FLASH data logging IC, with an auxiliary 16F87 controller to act as a servo-driver and fail-safe parachute release. Software is written using MPLAB as the IDE shell, and the ANSI compatible PCH Compiler, which CCS, Inc has generously provided on a student-license basis.

The autopilot hardware was spec’d, designed, manufactured and tested as part of a Ensc 494 project course under the supervision of Dr. Andrew Rawicz . Pawan, of the SFU electronics shop, was also of great help in sorting out various circuit design issues and part selection.

The goal throughout has been simplicity and low maintenance time. The old glider was far too intensive; a day had to be spent virtually rebuilding it prior to each launch, and a solid hour of preflight checks. This one self-recharges, self-preflights, and needs no adjustment or tuning.

Now, for the ground end:

I’ve finally caved, and written a ground system for windows. Oh well. It allows such things as linking into out-of-the-box moving map software, and USB drivers, too big a benefit to resist.

Pan

A greater improvement, however, is an automated pan and tilt constructed by Owen Walsh, an old friend and Civil Engineer (as well as skilled programmer, he’s also doing the driver software for it). This unit will include its own Atmega128 based microcontroller, and a 915mhz hopper radio for telemetry contact with the glider, both on a single USB connection.

Not having to attend to the antenna pointing allows a higher gain antenna, and easy video-recording of test flights and landings.

For fun, I’ve thrown in some photos of the ground antennas. Each antenna was modelled using NEC2 software, an open source finite element package. This package can model the far-field gain of almost any antenna geometry, as well as take into account surrounding structure. This was invaluable in finding an antenna placement for use onboard the glider that didn’t have a squashed-spider shaped far-field pattern.

The main ground antenna is an 11 element, 915 mhz YAGI-style, initially designed using a standard script , and then tweaked using NEC2. It’s made entirely out of brass, joined with lead-free solder.

Here’s the lower-gain antenna with a magnetic base and broader reception pattern, for use if we end up doing a ground search:

Well, that’s it for now. As you can see, the hardware end of things is mostly done. “Just” software completion left to go. Just….and summer sailing season approaches. Sigh. I’ll keep you posted.

* * *

  1. I’d still like to see the next flight, but it will be a little more difficult now that you are on the other side of the pond. It will be worth the journey though.

    I tried a lot of neat projects to keep me sane in grad school but we were barely out of the vacuum tube era. This is way better than anything I dreamed of.

    Good luck and keep up the great work,
    Rick in Victoria.
    — Rick    Jun 23, 10:46 PM    #
  2. PS I used be part of a group we called Boffins’RUS which we adopted when we were called “boffins” as a pejorative.
    — Rick    Jun 23, 10:59 PM    #
  3. This is fasinating to the nth degree. The pix and tech background are very interesting. It is very inspiring to see your progress. I will keep checking back for your updates.
    Chris -Salem OR.
    — chris    Jul 3, 03:38 PM    #
  4. Truly inspirational! I can blink some lights in different patterns with my microcontroller…I will be glued to this site to learn more.
    — Greg    Jul 12, 03:04 PM    #
  5. This is very cool. Just a quick question :- I noticed that with the first glider your Windows-based ground software proved unreliable. Given this, why have you decided to go with Windows again – rather than Linux?

    All the best,

    Ian.
    — Ian Clarke    Jul 15, 02:51 PM    #
  6. What about using a cell phone as a comm system? It seems like that would get you much better range of coverage (5-20miles LOS) than other signal choices, though you may not have the desired throughput.
    — Tim    Aug 2, 01:56 PM    #
  7. I noticed you moved away from the PC-104 computer to a microcontroller… Did you happen to see the gumstix computer? Seems powerful enough and certainly small/light enough for your application.

    http://www.gumstix.com/
    — Matt    Aug 17, 05:59 AM    #
  8. I am interested in knowing what kind of data radio you are using for telemetry broadcasting on the new glider. I know you used the TEKK radio and a YAM on the MK I. You mentioned you have a “hopper” radio on the ground for receiving telemetry, but no mention of what is on the glider. Thanks in advance.
    — Aaron Stephens    Aug 29, 10:38 AM    #
  9. I just want to let you know that this whole project is really inspiring. I am a senior in high school and have been building R/C planes and helicopters as far back as I can remember. this project is pretty much exactly what i was plaaning on building, except mine was going to be a lot bigger and have a nitro-engine with many fuel tanks. Currently, I am in need of assistance from someone who has programming background. Hopefully, my project will take off soon. Best of luck in the future!
    — Brandon    Sep 6, 09:51 PM    #
  10. Great work! I have been checking out this page for a while, and remember first reading about your glider many years ago. I cant wait to see images from this one when they come: I expect that modern digital cameras will give even better views than with the web cam before.
    — Alex    Oct 4, 06:23 AM    #
  11. I really like reading about your projects. I have been thinking about the post above about using a cell phone… A GPS enabled phone would be useful, but come on being able to call your glider and listen for the ringer would be priceless… :-)
    — Joel    Oct 16, 11:09 AM    #
  12. If you bring it out to the Okanagan I am sure my neighbour will drop it from his helicopter all day long for flight tests. We are both very interested in the project. I have a cleared block of land for you to land it on too.
    — Gordon    Oct 19, 08:39 AM    #
  13. Man, almost 6 months and no updates. You’re killing us here! What’s going on with the project?
    — JC    Nov 24, 11:56 AM    #
  14. He updated at the beginning of November—look here:
    http://artvb.oatmeal.dhs.org/index.php?id=7

    It’s possible that you just bookmarked this one article. Try this url instead: http://artvb.oatmeal.dhs.org/
    — Colin    Nov 29, 12:27 AM    #
  15. Thanks Colin. You nailed it.
    — JC    Dec 10, 08:52 AM    #
  16. Where are you with this project?

    It has been too long, since updates! I hope and want to see the same brilliance demonstrated in Project 1.

    “You got us all on a hook!”

    Launch Date!!!!!

    Thanks,
    Kevin Shea
    Beacon, NY USA
    — Kevin Shea    Aug 19, 10:29 PM    #
  17. I’ve very much enjoied reading about you exploits. I’m currently working on my on balloon launched near space project and plan to try a glider launch sometime next year. Would you be willing to share your design for the mkII? I think with vaccuum injection and kevlar/carbon fiber I might be able to construct a very light and extremely durable (See Impact Resistant) Glider.

    Don KI4QVO
    — Don    Sep 9, 12:43 PM    #
  18. Hi, I do embedded stuff for work. Your project is inspiring, pulling together so many technologies and skills, great stuff!
    Using a GSM/GRPS cell phone would be a goer they are smaller than a matchbox and only cost $100 in quantities of one, see http://www.telit.co.it “modules”
    It is programmable in Python and has a full TCP/IP stack.
    Regards, Robert, Sydney au
    — Robert    Sep 20, 06:35 AM    #
  19. I like your antenni but how about disigning something like this
    http://www.byonics.com/dsp-rdf/
    But for your freques. for finding a grounded plane. It’s suposed to work with aprs too.
    Shawn
    P.s. love it!!!
    — Shawn B.    Oct 14, 09:35 AM    #
  20. I just noticed your site today, and I am excitedly reading all of it. Thank you for documenting your projects in such a fun way!

    -David in California
    — David Duval    Nov 13, 04:59 PM    #
  21. Art,

    I really enjoyed reading about your first robotic glider and have been eagerly waiting for updates on this second one. Has there been any progress?

    Thanks!
    — Jeff    Dec 8, 08:18 AM    #