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Another camera refugee ...

Discussion in 'Phantom 2 Vision + Discussion' started by djczing, Sep 26, 2014.

  1. djczing

    Sep 19, 2014
    Likes Received:
    ...but I don't want to dwell on the crash which caused the breakage of the ribbon cable /and/ the gimble itself.

    My son and I replaced the cable (he did all the work - im an idea man ya know). We locktited (red) the shaft as found on this board (great writeup(s)! Thanks!) after orienting/aligning it. We thought sure that would do it - but while the camera now worked again, the gimbal still flops around like its plugged into the wall. All 3 axes are in action. Cables look good - theres one thing Im wondering which is how many turns can you get on that trim pot - whats its range in terms of turns ?...

    So, the gimbal is broke. I worked on it some this morning and verified (again) that everything was right, but still no joy.

    So, I took the cam/gimbal assembly off the airframe, and did the GPS shield mod. I didn't foil down the arms at all, I just foiled the center section. I think someone here mentioned that there appears to have been a change in the way they do the GPS cable/shield - but the aluminum tape went on anyway, then the vinyl (no, not Led Zeppelin).

    Finally, I did the IMU advanced and also recal'd the controls. I also put manual mode in the switch too for emergencies, and just in case a cameraless aircraft is the perfect reason to make the first try fully manual.

    First flight in 2 weeks, and first flight after a hard crash into the pavement. I wasn't able to lock 6 satellites on the first battery, which was interesting. The sun was about 10 degrees up in the west, and/or perhaps the constellation just wasn't out to play at that time. I was disappointed that the foil mod didn't yield me instant GPS acquisition and home lock. I had to do what I usually do, which is get up about 40-50 feet in ATTI, wait for sat and home lock. This was no different.

    So on the happy note, the second flight was very different. It locked GPS right up off the bat and home-pointed. In fact, I waned to check the EMU again, so I have it in my office in the house, plugged into the assistant - and it hits rtf - gps mode. Once I get a cam and telemetry back on the bird, then ill be able to make better comparisons, but I think its promising so far.

    Without the cam/gimbal, the aircraft was more nimble (im no expert pilot, but can now hold my own). I also noticed it was a little heavy in the back. The first time I spun it up since the crash I brought it up real slow to check balance - and it tipped over on the aft prop gurards. Did it again - same result. So, the cam/gimbal must put jussst a little weight forward. You can easily punch the bird up off the ground, but after those first 2 tests, it took a little nerve to pop the big bug up 6 feet. Everything was fine.

    The only thing is (and this is what has me looking at the IMU so often), is that ive seen a couple times where the bird will just wobble - more aileron-ish, and not VRS, and around 360 degrees. Seems like a flight control condition which could easily induce VRS, and it caused me to come down from 50 feet (still flight testing). I set it down and did the compass again, and never had an issue again - so is a 2-5 degree variance on the x-axis in the IMU alignment normal ? I see it says its raw - I guess it is (more raw than I like to see) - but it must be dampened out by software filter/timer/whatev-er.

    The other thing I noticed (again) is that the new props don't sound like the old props. Ive had 3 sets of props on this bug, and noticed something different in each - although in this case, the guards are new also. On the last set, it sounded like one prop was ripping at the air more than I was used to. When I changed to this set, now it sounds like the starboard quarter thumps at the air more. No control problems or revving to compensate, and the flight is fine. Never had the wobble again, and finally got back up in the air. (heheh I never did switch to manual mode, due to the seeming slight weight trim issue).

    Anyway, I could blather on, but its just good to be back in the air ! Lets hope the phantom stays around for me to fly it - although going through the innards, there wasn't a hair out of place. Everything down and tight after a hi-G crash.

    /wax off.

    Everyone have a good weekend.