brainwagon "There is much pleasure in useless knowledge." — Bertrand Russell


It’s quiet… too quiet…

I received my second email inquiry yesterday (yes, two whole emails) asking me why I hadn't been posting to brainwagon lately. It's gratifying that both of my readers would each send me a note asking if things were all right, so I thought rather than addressing you each separately, I could double my efficiency by creating a post.

There are many reasons for my apparent slowdown in posting. My new project at work is taking up more time. I haven't done much amateur radio lately, mostly because I need to rework my antennas (I want a more permanent way to route coax inside, rather than just "opening a window"), and the programming muse has seemingly left me: I can't seem to muster a lot of enthusiasm for it at the moment.

These would by themselves normally be enough to slow me down, and perhaps bring a temporary halt to blog posts. But there is another reason: the unavoidable drone of the election season.

You see, I'm a person of fairly strong political convictions, and the election season always presents enough fodder that daily I find myself yelling at the television. My temptation in moments of weakess is to turn these diatribes (well founded as I believe them to be) into blog posts, but I don't think that my readers (both of you) come to brainwagon to read my political positions. If I invited you to my house for a barbecue, I'd be a terrible host if I simultaneously subjected you to rants on the subject of politics or religion. I view brainwagon as a place where I can talk about interesting things of little consequence. I'm going to try to keep it that way.

On the brighter side: some cool projects are underway. The F-22 RC airplane I began several weeks ago is mostly completed. With the help of Mark Harrison of Eastbay RC, I had the thing entirely assembled, and we were set for a trial flight on Friday, but sadly after a week of beautiful weather, Friday dawned cold, with a light drizzle and strong gusty winds. We might have braved it, but I noticed at the last minute an issue with a loose control horn on the elevon, and it would not have been controllable. It needed a return to the workbench for a fix.

When I got back home, I pondered another problem that I had with my assembly, if you check out the following video, note the placement of the servos:

Did you see the issue? the servos are mounted very near the slot where the propeller will be mounted. In fact, when the elevons are in the down position, the little control arm for the servo comes uncomfortably close to the propeller. I decided that while I was fixing one of the control horns, it would be good if I unglued the servos and mounted them further back.

And here's where having a great mentor like Mark really helps: he informed me that isopropyl alcohol applied to the glue joint would wick in, and I'd be able to peel the glue off. A trip to Walgreens and $2 got me a nice bottle of 91%, which I applied with a cotton swab. A few minutes of waiting, a little wiggle, and the servos popped right off. A little more alcohol applied, and I was able to peel the remnants off the foam and the servo. Very cute.

Today, I hope to get the new, shorter control arms in place, with better control rods in place, with hopefully less flexure. Then, the question will be: dare I try it out? I actually have no experience at all with RC planes: I was going to rely on Mark to help me get it off the ground and maybe avoid a crash by using "trainer mode" on my transmitter (enabling him to take over and fly). I probably shouldn't have begun with the F-22. Something with some dihedral and maybe even a real airfoil so it can glide in without power would be better for a beginner, but it looks really cool. 🙂 I expect that after two or three flights, it will be in such bad shape I'll have to harvest its organs for use in another plane. But I will have learned alot.

I've already begun to plan a second plane, and to acquire the parts for it (whatever it turns out to be). Ultimately, I'd like to get to the whole FPV (first person video) setup, and be able to fly with cameras aboard, but I think until I gain some experience, it would be pointless (or even counterproductive) to spend lots of money on equipment. After all, you have to walk before you can run.

But I did find an interesting gadget that's a baby step in that direction: an $8 Turnigy keychain video camera. It records MP4 video at 640x480 resolution onto a microSD card (not provided). I had a 4GB class 4 card, which worked okay for early testing, but it seemed like it had a problem maintaining full frame rate with that, so I ordered a couple of nice little Class 10 cards from Amazon, and they seemed to work out very well. Since my plane isn't ready for flight testing, I decided to test the camera by velcroing it to the license plate holder on my car, and taking it for a short 15 minute drive. I then took the video and post processed it with ffmpeg to turn it into a time lapse video (25x faster) and got this result:

The overall clarity is not bad: the automatic exposures can sometimes lower contrast and wash out the image, but perhaps less than I might have expected. The biggest problem I suspect I'll have is that the field of view is quite narrow, and thus when mounted on the airplane, may jerk around a lot. But for a total investment of around $17, it's perhaps better than I might expect.

Stay tuned for more, and thanks for your patience!

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  1. I just got one of those Turnigy Keychain Video Cameras. I was wondering if you got any documentation with yours? All I got was the camera wrapped in bubble wrap!


    Vince – WB2FYZ

  2. Nope. No documentation, but you can look up generic “808” style keychain cameras from Chuck Lohr’s website. To just get a quick reference on turning the camera on and off, try this page.

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