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- Apr 25, 2016
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I truly believe in sport mode sensors are not activated at all most people crash because they don't realize it sorry for your loss hopefully it can be repaired and fly again
Sport mode losing altitude, crash.
- Thread starter btucker
- Start date
Its not. Sports modes still uses gps for position locks and there does NOT drift in the wind. ATTI on the other hand does not use GPS for position WILL drift in the wind.
Sports mode just simply turns off the additional sensors like VPS and OA on some models. It is turned off at higher speeds as the quad maybe limited by the sensors hardware or onboard computing power.
Chris, on the P4 obstacle sensing is disabled in Sport but GPS, VPS and the Barometer still work normally.
I sent the Phantom 4 off to DJI for repair Thursday. I'll let everyone know how that goes. I ordered a Mavic Pro Wednesday evening and it arrived Friday, unbelievably fast. Flew the Mavic today and it is really cool. I love the portability of the Mavic but I want my Phantom back too. The Phantom 4 is more visible when flying and thus a little more fun to fly. Both have their benefits.
[I crashed my P4 last night doing some high speed passes across a frozen lake in sport mode. I was going in a straight line at about 35 mph. All my telemetry said I was 30-40 feet over the surface of the ice. However, what I didn't catch was a -1.0 mph vertical speed. That must have been coming from the IMU? I got about 200 yards out from the home point and my P4 tried landing at 35 mph. Fortunately for me there appears to be no damage, and the ice was strong enough to support me on snowshoes to go for the retrieve. Reviewing the video, I see several high speed passes where I start out 40 feet above the ice and slowly drop to within a few feet of the surface. When I stop at the end of the pass, the P4 rebounds to the 40 foot altitude. I'm conjecturing here, but could there be a ram effect from the high speed on the barometric sensor? The faster you go, the baro sensor gets fooled into going lower?
Wow, obviously the VPS had next to no chance of working in those conditions so the AC is depending entirely on its barometer for height. I thought the IMU only measures horizontal movement so it has no input to altitude control either (but it may contribute the vertical speed display) so your theory on speed affecting the barometer is plausible although one would hope DJI would have picked up something like that during development of the generations of Phantoms.
I don't recall where I saw it but there was a thread a couple of months ago (I think on PP) where several AC were losing altitude during supposedly horizontal flight after an update. My recollection is that the thread wasn't resolved but I may not have followed it long enough.
We don't have frozen lakes (or even much water at all in inland Australia) but I understand they are fairly featureless things. Even so I am intrigued to know how you didn't see your P4 go from 40ft to basically 0 several times and then bounce back to 40ft all without showing any change in altitude on your screen. I would suggest you are very lucky to still have an undamaged AC.
I wasn't as lucky that i am able to recover my drone. Started on a 10 metres altitude and flew almost a kilometre before switching into sports mode. Then things changed. Interestingly, my control record still has the original altitude at the point of the crash.
