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Most recent entry: 2011-05-28 00:00:00 -- Generated on 2012-01-31 22:30:08 by Rig3 0.4-440



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2011/05/28 A bit of RC flying with Daniel
π 2011-05-28 00:00 in Rc
Since Daniel was visiting us from NYC, this became a good excuse to go flying at Rancho San Antonio, so we did :)



I did most of the cularis flying, so no pictures in flight :-/
I did most of the cularis flying, so no pictures in flight :-/

See more images for A bit of RC flying with Daniel
2010/10/13 Overfly of Google HQ Campus and Shoreline Amphitheatre with Minimag Cularis Motor Glider and GoPro HD Camera
π 2010-10-13 00:00 in Rc
Ok, so let's settle the tech part first, I figured I'd get the best video by filming from under the Cularis, but since it doesn't have any gear, that means the camera is first to touch the ground on a landing. As a result, I padded it, to lessen the impact and the glue that holds it to the bottom of the glider does give out under impact.
Now, this is not ideal so my plan was also to land in the weeds like I would do at Rancho San Antonio, so the wings get caught in them and the bottom of the glider doesn't touch the ground. The weeds at Shoreline were not very tall though, and because they were far from me, I misjudged the height on landing and landed a bit hard on the ground, which did tear off the camera from the plane, but otherwise everything was fine, the padding worked and the video was intact.
All this to say that this setup however doesn't allow for easy repeated flights :) Takeoff is done at full power with a heavy toss and if I have enough back elevator I can miss the ground despite the added weight from the camera and resulting loss of aerodynamism from having that heavy block handing from under the glider.

you can see the camera under the belly
you can see the camera under the belly

I get 20 to 25mn flight time with one battery, which was more than enough, and captured the frames below from the HD video. I'll say that unfortunately the HD video quality from my GoPro HD is far from stellar, but it beats the original video I was getting with the non HD versions that came before it (see my first attempt at it last year with my original GoPro hung from my Minimag).
The Biggest improvement from my attempt last year was that the Cularis was much bigger and easier to see from a distance. I was easily able to fly much farther from where I was standing (about a mile) without totally losing track of which way the glider was pointing and how I could still control it to fly it back (which definitely was a problem with the much smaller minimag).

Below are frames I captured from the video:

original main campus
original main campus







the 'famous' bridge to 1950 :)
the 'famous' bridge to 1950 :)

1950/alza
1950/alza


46/47
46/47

45 and the droid/eclair/cupcake
45 and the droid/eclair/cupcake

1098 and 900 alta with 101 in the background
1098 and 900 alta with 101 in the background

1965
1965

1945 and rengstroff
1945 and rengstroff

After getting what felt like enough passes over the campus buildings (the so called 'GWC' was a bit out of reach for safe flying), I did a few passes over the Shoreline Amphitheatre:





Putting aside the fact that my landing wasn't that stellar, this was my only flight and the video was good the first time (thankfully I had gotten some practise shooting from a distance and 'aiming' at targets from almost a mile away). The video quality wasn't awesome but I guess that's as good as you get from a cheap-ish HD camera you can stick onto a small RC plane, so it's not too bad.

2010/08/14 Overfly of Rancho San Antonio with Multiplex Cularis and GoPro HD
π 2010-08-14 00:00 in Rc
I had been doing some gopro flights with my minimag, but it just wasn't a great idea because:
  • The minimag is just too small and hard to see from a distance, which is why I already lost one plane and camera after losing the plane because it was too small after it got caught in a strong wind.
  • The minimag needs a lot of power to stay airborne with the weight of the GoPro HD. The wing loading is just really high with that extra weight, and my last flight where the motor died on final, I barely managed to land while dropping from the sky at what felt like less than a 2/1 glide ratio.
  • A byproduct of the minimag's wing loading means that I have to run on power at all times which causes both noise and vibration, neither are ideal for filming.
  • That also means that I can't run the battery that long and the flights aren't much longer than 10mn.
  • If I do lose the plane, better lose a much bigger one that's easier to find in the weeds :)
  • The one issue with the Cularis is that it has no landing gear, when putting the camera under the plane, that's the first thing to hit the ground on landing, which ain't ideal (I saw someone who put the camera under one wing and used a counterweight, but the view isn't as good.
    I ended up putting the camera under the plane with some foam to protect it and planned to land in the weeds. For my 2 flights, that worked fine although it wouldn't work as well if I had to land in a parking lot :)


    My first flight (video below) was 16mn and went fine. The second flight lasted a whole 25mn, although that was pushing it, the battery died just as I was landing (i.e. I got lucky :) ).

    I took some 3Mpix shots from the video, a few are below:

    the flying field
    the flying field


    hwy 280
    hwy 280

    the next door cemetary
    the next door cemetary

    another nice view of the cemetary
    another nice view of the cemetary

    they have a nice array of solar panels
    they have a nice array of solar panels

    nice houses next door
    nice houses next door


    why do people fill their garages with junk and park outside?
    why do people fill their garages with junk and park outside?


    Here is the video of the first flight:

    2010/07/28 Taking over a Multiplex Cularis
    π 2010-07-28 00:00 in Rc
    One of my coworkers was moving to NYC unbeknownst to me, and I had noticed a glider in his cube. When I asked him about it, he said he wasn't sure what to do with it because he was moving out of California that evening.

    Needless to say it was not a hard sell, I offered to take it over and fix it up. The tricky parts were getting a new prop without knowing what motor was inside except for the fact that it was a competition motor with enough power to blow a speed controller or a lipo if either were undersized. He told me a story of one of his gliders where the lipo caught on fire while flying and they saw the glider gliding away while on fire :)

    First, the glider is huge. Its wingspan is more than 3 times the one from my old trusty minimag, and about as much as 2 of my bigger planes combined:



    The other tricky bit was setting up a radio. This was actually the hardest bit because while I had had the foresight to by a more expensive Spektrum DX7 back in the day and therefore had 7 channels, the DX7 was just a pita to configure for crow/butterfly flaps assigned to the power stick like in this picture (ailerons up and flaps down):


    It turns out that the mixers in the DX7 barely allow you to use the power stick to either control the motor, or the crow flaps at the flip on one switch, but it's super non obvious. I owe a big big thank you to the guy who figured it out and wrote this post:
    http://www.parkflyers.org.nz/modules/newbb/viewtopic.php?post_id=4193
    Not only he gives the setup, but he explains what the DX7 manual doesn't do: how the hell this all works. This in turn allowed me to improve on his programming and have just a single switch that goes from normal airplane mode to crow flaps and back.

    The last piece was figuring out if the ESC's BEC was able the power the 6 servos (in theory, 2A is only good for 4). An amp meter on the battery while moving all the servos seemed to show that things were ok on that front. The only part I just didn't know about was how many amps the motor would try to get from the battery and how far I was from the 15-20C (about 40A for a 2100mAh lipo) I would be.

    After a long time programming the radio, I finally convinced myself that the plane would fly, I just wasn't sure about the motor situation... It turned out that if I went past half throttle, the ESC shut down to protect itself and the battery, so launching with power was quite an interesting task, I had to put just enough power but not too much and throw just right or I would crash.
    I did crash a few times after some not good enough throws, but eventually got the sucker to fly. I got the hang of it very quickly and I saw right away how it must be nearly impossible to land without the crow flap setup: even with it, I stayed over the ground in ground effect without actually landing for quite a while.
    I tweaked my programming after a few flights and was able to get a little bit of uplift and glide at Rancho San Antonio.

    I've ordered some bigger batteries that should give me more power and hopefully let me run the motor without it shutting down when I actually need it :) and I'm looking at ways I could put my gopro camera on the glider once I feel that I have enough power to take off without risks (unfortunately, I can't put the camera under the glider since the glider lands on its belly, which would damage the camera on landing).

    It was a fair amount of time to setup (and I didn't have to build the whole glider), but it's been fun so far. Now I have to get the hang of how high I am and whether I could safely land back without power if I had to.

    Fellow glider pilot at Rancho San Antonio:


    See more images for Taking over a Multiplex Cularis
    2010/02/27 Minimag Crash Lipo Fire
    π 2010-02-27 00:00 in Rc
    Right after receiving my new motor and mounting it on my plane, I went for a quick test flight at the local park which I've flown at before since it's closer than Rancho San Antonio. I thought I'd save a few minutes by going to the park since I just wanted to have a feel for the new motor.

    Ok, I'll save you the details, there was wind (no big deal), I was too close to the street at end of the park and when I made my turn to land back close to where I was, the plane flew right into the sun. I got blinded and by the time I could have seen it, I tried to dodge a power/phone line and lost. The plane hit the line motor first, and the plane fell right onto the street outside the park.

    I have to say I actually had a string of good luck there:

  • cars avoided running over my plane (thank you).
  • plane actually got fairly little damage, glue to the nose will fix it.
  • the motor shaft didn't get bent and the motor looks fine.
  • prop is broken, but that's why I buy packs of 10, no biggie.
  • the only reason why the plane wasn't flying 1H later was the plastic piece that is holding the motor is broken and I'll have to buy another one. It's more the time to go get one than the $3 it likely costs (update: very strangely, one of my aileron servos died, considering I have zero impact damage on the plane, I was very surprised when I went to the field after fixing the plane, and it failed preflight due to a broken servo. Bummer, now I have to wait a few more days for a replacement...).
  • lipo got compressed during the sudden stop but looked ok.
  • Plane damage isn't too bad
    Plane damage isn't too bad

    I had a look at the lipo and it looked like only the connector piece of it got compressed but the 3 sheets of lipo were otherwise unbent/unarmed. The lipo looked ok so I put it back in my car with the rest of the pieces and drove home.

    A good 25mn after the crash, it self ignited on the desk I was working on. I was able to throw it on the ground and then away from close to my car where it landed while the 3 layers of lipo ignited one after another. Nothing actually got burnt despite an otherwise intense fire as the 3 mostly fully charged layers caught fire one after another (it shot pretty vivid flames 2 feet sideways). Sorry, I was too busy watching the fire to take a video :)

    this is what's left of the lipo
    this is what's left of the lipo

    Needless to say that on top of very limited damage to my plane, I'm very lucky that the lipo didn't self-ignite in my car's trunk, or later on when I wasn't watching it.

    Moral of the story, a charged lipo that got any kind of reasonable shock is a ticking timebomb! Check Lipo Fire on youtube for more examples.

    100_Lipo_Fire 200_Minimag_Crash
    2010/02/26 Higher Altitude GoPro HD Flights at Rancho San Antonio and Motor Failure, and Video recovery from SD Card
    π 2010-02-26 00:00 in Rc
    After adding a tail ribbon to my plane (to make it easier to see where is the front and back when it's far away from me), I went for a few more flights to catch some higher altitude HD video.

    My first flight went mostly ok: (make sure to select HD in the resolution slider)

    Unfortunately, on the second flight, the motor crapped out. First it started vibrating a lot, hence the shaky video, and when I removed the throtlle in flight when preparing for landing, I wasn't able to re-engage it. The video after the fact gives the 4 beep code from the ESC which means motor failure, shutting down. At that point, the minimag with all that weight feels like a 2 for 1 glider at best. I don't remember if I tried to flare, but it looks like I barely had enough lift glide energy left to make it to the edge of the hill (beyond that, it would have gone below my field of view)
    Turns out I was able to restart the motor on the ground after a full shutdown, but it didn't restart in flight and you can hear the unhappy motor sounds :)

    Just like motor, the video had a problem: after downloading it on my laptop, I screwed up while recompressing the first video and wiped the second video in the process. The second video was still on the sd card, but its cluster table had been freed since I had reused the card already.
    In this case, photo recovery software usually only has to find the signature of the file by scanning blocks, read the file header and deduce how long the file is from that info since it's already lost in the cluster table, and then rely on the fact that all blocks are super likely to be contiguous, so you can just keep reading linearly until you have the whole file. This usually worked well, but Christophe GRENIER's very handy photorec wasn't succeeding there, and neither were other pieces of commercial software I tried: the restored file would not play (I restored the file by hand myself too by just copying the blocks and got the same result).
    In the end, I got really good help on the mencoder-users list from Reimar Döffinger, whom I owe a debt of gratitude to: he looked at my sd card image and figured out that my GoPro HD Camera wrote the index-related part of the file header, after the data blocks. With Reimar's help on what offsets I should be looking at, I was able to get the first part of the header at the beginning, concatenate the end of the header that was written after the data blocks, and then add the actual data blocks. After almost 2 weeks of trying, his answer worked and I got my file back. If you are interested in more details, see this message from the mencoder-users list.

    Here it is: (make sure to select HD in the resolution slider). Jump to 04:20 for the motor failure.

    2010/01/31 GoPro Wide vs GoPro HD
    π 2010-01-31 00:00 in Rc
    I recently bought the GoPro HD to replace my GoPro wide. The rationale was of course to get HD video, and for that the GoPro HD does deliver (full 1080p 30fps video).

    A 4mn clip comes to 360MB in H264 video from the camera, and I can recompress it with virtually no visible loss of quality to 100MB with mencoder set at 3200kbps for H264 (or almost 100MB/mn down to 25MB/mn).

    Changes with the GoPro HD so far are:

  • it's just very slightly bigger and heavier, but my plane still takes off with it
  • it has an internal li-ion battery which should last a few hours (GoPro Wide lasts almost 2H for a set of rechargeable AAA batteries).
  • the current firmware does not support shooting upside down, which I do in my plane and car. For now, I use software to flip the images and video.
  • more importantly, it's supposed to support SDHC up to 32GB, but for me it fails with my 16GB card so I use 2GB SD for now (that's only about 20mn at full quality before it fills up though). Hopefully they'll fix it in a new firmware.
  • more sadly, colors look washed out on the GoPro HD for me. I contacted support about this and will see what they say.
  • Here are some pictures comparing GoPro HD colors vs GoPro Wide (that's the 2 pictures per second mode where both GoPro Wide and GoPro HD take 5Mpix pictures). Just in case you ask, pictures were taken just a few minutes apart with the same amount of sun.

    GoPro HD: Nice crip picture, somewhat dull colors
    GoPro HD: Nice crip picture, somewhat dull colors

    GoPro HD: Still nice crip picture, somewhat dull colors
    GoPro HD: Still nice crip picture, somewhat dull colors

    GoPro Wide: Picture slightly less crisp, more vivid colors, more blurry around corners
    GoPro Wide: Picture slightly less crisp, more vivid colors, more blurry around corners

    GoPro Wide: Just prettier picture except for blurriness around corners
    GoPro Wide: Just prettier picture except for blurriness around corners

    So far, I'm a bit torn, the every 2 second pictures are just nicer on the older GoPro Wide for me, and the early bugs on the GoPro HD had better get fixed (SDHC support and taking pictures upside down at least). No idea if the washed out colors problem is solvable or not. If not, that would be a shame.

    But yes, the full 1080p HD video does beat the old 512x384 videos hands down though :)

    Here is a link to the full 1080p video recompressed to 3200kbps and a link to the youtube page with the video (which allows 720p and 1080p viewing).

    See more images for GoPro Wide vs GoPro HD

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