And yet DJI used to tell us we needed to re-calibrate at every new flight location. Must be the same engineer who scripted the full discharge every 20th cycle for the flight packs instruction.
The amount of misinformation and contradictory advice on the compass issue from DJI since the original NAZA-controlled Phantoms is pretty remarkable. I've tended to assume that it is simply poor communication between their engineers and whoever writes the instructional materials.
N017RW
Premium Pilot
The original reason for the deep cycle was to improve the accuracy of the battery monitoring system. This has been improved since the P2.
As far as compass, that’s one that is more about superstition as many do not understand what compensation does or care to research it.
Yes- DJI’s battery suppliers are now implementing versions of the Texas Instruments Battery Monitiring solutions that constantky measure cell health and performance in real time, that is well known. That’s why the silly instructions in the manuals seem so ridiculous.
Or perhaps misunderstanding of DJI engineers of the external component suppliers data sheets.
N017RW
Premium Pilot
It may have persisted in the P3 doco, I don’t think it is in the P4 manuals. It is still seemingly recommended by DJI support (based on said experiences of members here and elsewhere).
N017RW
Premium Pilot
So to clarify then, recalibrating the compass is not necessary everytime you change location ? This is the first I've heard that so just want to be sure.
I wonder if that may have been a contributing factor in problems I had awhile back ?
I wonder if that may have been a contributing factor in problems I had awhile back ?
msinger
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No. It would be best to follow the tips in the Compass Calibration Guide.
The one time I encounteted the toilet bowl effect with my P3S was during a landing at the lake cottage. At 20' up, I got an error message saying magnetic field interference with a resulting yaw error, then it switched to Alti mode, and all hell broke loose. In hindsight, I assume all of that was because it was it was landing a bit too close to the boat.
Sound like fun. The classic FC-induced toilet bowl effect occurs when the compass and IMU yaw values differ by around 90°, and will only occur in P-GPS mode. Toilet bowl in ATTI has to be pilot-induced.
Not so much. I was somewhat prepared for trouble when I saw it start swirling, and took it up and away when it switched from P-GPS to Alti. By then, I was trying to land it and avoid the boat, the lake, some peeps, and a very large tree. I took the honorable way out and crashed it into the tree, and then into the lake. I'll save you the trouble and say it myself, "op error".
That may be a little harsh, especially if it was windy. Sounds like your initial response to climb out of trouble in ATTI was exactly correct.
Wind was probably ~10mph. I'd had two previous landings in the same spot that went without incident, so I wasn't expecting a problem. For whatever reason, that last landing went badly. Fortunately, the only damage was to the Phantom, although it could have ended much worse had I not acted at the first sign of trouble. Still, I'll take responsibility. Lesson learned.
Have you opened the Phantom 3, and mounted the top cover back the wrong way?
That directly caused toilet bowl effect on my Phantom 2. And as soon as i mounted the top cover back the correct way it flew perfectly again.
Just a thought.
That directly caused toilet bowl effect on my Phantom 2. And as soon as i mounted the top cover back the correct way it flew perfectly again.
Just a thought.
That doesn't seem right. The only component mounted to the top cover of the P2 is the GPS antenna, which doesn't care about orientation relative to the aircraft.
N017RW
Premium Pilot
Agree in principal.
Going out on a limb here... IF the top shell could be rotated and it created a slight magnetic profile ‘difference’ due to the GPS components location re-callib would correct this.
Not sure the shell could be rotated though. It’s been a long time since I ‘cracked’ mine open.
Going out on a limb here... IF the top shell could be rotated and it created a slight magnetic profile ‘difference’ due to the GPS components location re-callib would correct this.
Not sure the shell could be rotated though. It’s been a long time since I ‘cracked’ mine open.
It can be rotated - I happen to have one of my P2s open and I just checked. With the compass location in the landing gear it's hard to see how anything in the top shell could cause enough magnetic distortion to be detectable, let alone to cause the TB effect - that needs somewhere around 90° error.
N017RW
Premium Pilot
Well the last time I cal-ed compass in my P2 (~3.5 yrs ago) was after replaing the Rx with a Futaba type.
I waited until I flight tested it to see what effect would be. Had some minor TBE so I re-caled and it was gone.
Just sayin’.
