Following on from Part 3, just when I thought things were going quite well with the MJX the dash cam stopped working. So while waiting for a replacement camera I did some more work on improving the camera mount and I also put in further flying practice. While my flying skills had started to improve, I was still a little prone to flying into trees, though far less than earlier. In fact, I’ve managed to improve so much that I was recently able to walk the MJX about an area at Mossvale Park that is quite closed in and with more than enough trees and large overhanging branches that would have instantly taken out the MJX a week or so ago. That surprised me greatly and I had a bit of fun manoeuvring the MJX about before I moved to the large open area for some more vigorous flying and tuning. I guess I’d finally started to get the hang of things and it also helped that there was no wind about on this particularly cold morning, so I was looking forward to more of the same.
However, one issue that I started having was that I was suddenly losing the ability to keep the MJX airborne. It would take off OK, climb and manoeuvre, but when I brought it lower down, it would keep descending and land. No amount of throttle control would stop this from happening. I also noticed that I could only climb so high and no further. So something was amiss. Not having used the iMax for anything but charging, I decided to do a bit of reading and then see what the storage mode of the iMax would do. Perhaps the batteries needed some reconditioning, as I had been a bit careless by keeping the batteries at full charge over several days. Anyway, after putting the first battery into storage mode, it took the battery down to 8.14V, after which the iMax started beeping, indicating that it had finished. This was higher than the recommended storage voltage of around 7.6V (2 x 3.8V), so I adjusted the amperage from 0.1A to 1A and tried another battery to see what it would do and this one went down to 7.6V. Then I retried the first battery and it too now went to 7.6V, as did the third one.
So a few days later I took the MJX back to Mossvale park for some more practice and fine tuning of the controls. Without the camera or power bank attached, I found that despite the poor state of the rotors, once I had the fine tuning sorted out, I was able to fly and hover without issue. In fact I was quite chuffed at how well I was able to control the MJX and even keep it hovering for quite some time in the same spot without touching the controls. I’m not sure what was going on, as previously without the extra weight of camera and power bank, the MJX was diabolical to control, rocketing off in all directions and usually towards the nearest tree. Maybe I really was getting better at the controls, with the fine tuning helping immensely. The stability was so good that I managed to fire off some photographs just to prove that I was getting somewhere with controlling the MJX. And the battery issue appeared to be fixed, so I now keep the batteries at storage voltage until I plan to go flying and put them back to storage voltage after flying for the morning.
The other thing that needed attention were the very pliable rotor guards which, whenever I hit a tree or they contacted the ground, would bend and the blades would hit the guard and damage the tips. This one ‘feature’ probably damaged the rotors more than anything else before I realised why the rotors were getting mangled whenever I hit a tree or the ground. To fix this issue, I simply added a thin, flat, wire that’s used to stiffen wiper blades (taken form old wiper blades in case I needed them for something), cut and bent to fit through two holes I drilled at either end of the centre guard strut. The wire is under compression, so it’s trying to straighten and thus provides some stiffening to the guard. The wire fitted perfectly and now the guards are much stiffer, though still flexible, so that the rotor tips won’t hit the guard unless it’s a very forceful impact. And following a bit of a bingle, they do work.
And following a suggestion by an experienced drone operator on the RC Groups forum, I added some extensions to the MJX control levers and they made quite a difference to the sensitivity that I was experiencing. As I’d mentioned earlier, I was finding the control levers overly sensitive to my inputs, causing the MJX to overreact to those inputs and make friends with every welcoming tree. So I first added a screw to the pitch and roll lever (the one on the right), and this made a big difference to the way the MJX reacted to my inputs, making things less aggressive and sudden. The altitude and yaw control lever on the left is not as sensitive, but adding a shorter screw made just enough difference to also moderate inputs. Such a simple modification made quite a surprising difference to the controls and went a long way to adding that dampener effect that I wanted. But I then experienced some minor disappointment as one of the levers broke. Simple reason; I hadn’t inserted the lever screw deep enough, so some plastic glue and reinserting fixed the problem.
Even though I now had much better control over the MJX, any sudden movement would still result in quite jerky video. One option to fix this was to add a motorised gimbal and there are many aftermarket options available that, with a bit of makeshift work, enable you to mount and power the gimbal from the drone battery. I wasn’t really sure about this option at the moment, as it added a lot more weight and had it’s own problems. But as I waited for my camera to arrive, I did some further modifications a created a new fixed mount for the time being. The camera arrived shortly before this story so I was able to include some photographs and video.
The other thing that I tried out were some tri-blade rotors, to see if they would further tame the MJX, as indicated in a number of YouTube videos. The tri-blades came as a kit with extended skids and an interesting camera mount using a rubber mounted base. The extended skids worked well to raise the MJX off the ground, but as they didn’t extend forward and aft as much as the standard legs, landing became a major issue as the MJX would usually topple on landing. I also started experiencing quite a bit of vibration in the video footage and a massive power loss, so I did some testing with and without the skids and the same with and without the tri-blade rotors. As it turns out, the tri-blade rotors seem to be the the culprit, so I’ve gone back to the regular rotors and legs and installed the rubber mounted camera holder, which has helped.
Anyway, I’ve been trying to get in as much practice as possible and have changed my morning routine with the hounds, going much earlier to Mossvale Park so that there’s no one else around, at least so far. Going early in the morning as Winter approaches has its advantages; there are less people, it’s generally quite still and I can spend longer in the park than on a Summer’s morning. But as I improve, I might return to the cleared logging area where I did some camera mount testing and practice going up and down one of the tracks, as that’s what I’ll be wanting to do on our High Country Cruises, videoing one of our group approaching as they climb a track or taking video from behind as they climb.
The Mobius 2 camera that I ended up buying came too late for me to write up a review before this post, so hopefully next week I’ll post a review of this rather nifty little action/dash cam. My early impressions are that this is going to be an excellent camera overall and with a form factor that’s much more versatile than the typical boxy action cams. Part 5 kind of winds up this story.