Hi,
Well I fixed the issues from my previous flight, had to swap servo out 7 (connected to YAW servo) and then swap it again on my transmitter to get it to turn the right way. Thought great I'll go up to the oval for a test flight, but thought I'd best do a quick check of the new APM board in the front yard first, if you have read some of my previous posts this was never going to end well and I'm thinking of banning front yard flights for a while.
I put it in a nice clear spot, I turned on the transmitter, then connected the Tricopters battery, then fired up the telemetry. Good strong signal, at this stage I noticed the battery I'd been using was a little low on juice, I thought it's ok I'm only going to take off a few metres and put her down, what could go wrong.... (Stuff up #3)
I go to arm the board, it wont arm. I look at the telemetry data, it's got a great GPS signal (less than 30cm out I'd say), but it's getting a prearm compass error, compass was correct though. I decide to go in and disable the arming checks (stuff up #4). I arm the board and it all looks good. I start to power it up and it takes flight, god it was beautiful the stabilise mode is brilliant, never seen it so stable in flight before. Then 2 seconds later it starts to climb, I decide to lower the power, no response. Hmmm that is odd I think, so as a safety precaution I back the throttle right off, it still continues to climb but faster and faster. I decide to see if some stick input works (ailerons, yaw and elevator), oddly it does so I put it into a bank to try to loose some alt, it starts to lower, but it's getting faster and faster, so I decide to put the stick in full to the side and luckily it falls rapidly. Right then it was over a neighbours house 2 doors down and smack into their roof it goes. Crap. I disarm the board and I take a quick look at the telemetry data, yep it's on my neighbours roof two houses down. I notice the battery voltage is low, not normal low but really low, it was reading 7.4v for a 3s, i remember saying that's not good.. I go for a walk and sure enough I can see it on their roof.
A quick trip to my local unit and I pick up a collapsible ladder (was just a little higher than the ladders I have at home and damn it was tight spot to get the ladder in) and a long pole. 15 mins later and I have it down.
Damage report:
One cracked propeller
One cracked tail boom
couple of snapped zipties
One dead LiPO - cell checker wont even fire up
All up about $15-20 damage. No damage to neighbours roof, considering the condition of the tiles I was impressed. FC and associated items all seem to fire up on a post examination and test.
So if you noticed I started with stuff up #3 above, that's because after I checked the telemetry I was able to work out the other two. So the swiss cheese method has been used, my 4 holes lined up and created this accident.
Stuff Up #1 - Dont set any initial failsafes to RTL, have them set as LAND. I had both Geofence and low battery failsafes set to RTL. Change back to RTL once initial flight tests are completed.
Stuff Up #2 - Double check that home is the current launch site. I was playing with the setting the night before and loaded a mission that had it set to a playing field 500m away (which should have set the Geofence off, seems low battery takes priority over geofence).
So what have I learnt?
1. Dont turn off the arming checks they are there for a reason. Fix all issues before flying!
2. Always check where home is, I should have seen it on the map on the tablet but didn't notice it wasn't there.
3. I've turned Geofence and low battery to LAND, I'm sure I'll switch that to RTL but not until I trust myself some more, until then I'd prefer it lands and I deal with the problems of where it lands at that time.
4. Always start with a fresh battery, even for those quick simple flights.
5. That I'm a lucky bastard - had it flown to the RTL site it would have been over a group of kids playing some rugby, like right in the middle of their game.
6. Even for simple test flights turn on the camera so you get the cool footage of the copter going nuts.....
7. Take pics of the damage next time, sigh.....
So I've fixed the broken boom and remounted all the gear, what's great is that I needed to redo the rear boom to make more room for the FPV and Telemetry masts but it just hasn't broken until now.
If my OSD was working I would have known what was happening, but since my tab was 5m away when it started to go funny, I couldn't walk over. I need to get my minimOSD working.
I have two Questions for those with APM / HK Pilot boards:
1. Should have I been able to provide inputs when it went to RTL mode? I would have thought not? I have checked that in the telemetry it reports it as RTL mode. I'm wondering if the low battery was putting out less to the motors but in a non coordinated way and it just happened to be similar as my inputs?
2. If you have a HKPilot 2.7 / APM 2.7 board and MinimOSD, have you connected it to the DF13 plug the one marked I2C? If so have you got yours to work? Mine sits there waiting for MAVLINK to start, I've tried with no TX connected on the OSD and with a TX on the OSD. Have you tried to connect it using the piggy back harness on the telemetry? Mine seems to cause issues for the board and it wont start up - well the ESC's dont make music.
Cant wait to try it out again taking care of all the issues above that is :-)
Chris
