Altitude loss
- Thread starter SonnyFino
- Start date
What flight mode were you using at the time? I have noticed that my M2P does exactly the same thing when I am in Sports mode and flying close to the ground. Whenever I apply full forward speed the M2P always starts to lose altitude. I have found it doesn't happen as much in other flight modes. I am assuming that this is expected behaviour and you might be able to mitigate this effect in settings. Sorry I am still a bit of a noob regarding the technical side of things. Just my observations after 5 weeks flying.
Lets see what's happening.
Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
Come back and post a link to the report it provides
Bigbird48
Well-Known Member
Is your altitude on the screen going down?? When you fly forward it looks like the drones is losing altitude but its really just an allusion pull back on the stick so it comes towards you and it looks like its rising. Hopefully this is what your experiencing and its not really dropping. If your height on the screen says your losing altitude then you have a problem.
Hi, just a thought but I wonder if it’s only happening in sports mode could it be because the bird drops it’s nose to accelerate which will cause the rear blades to push it downwards? I had a Hubsan 501C and the manufacturer warned of this happening if flying forward at full speed.
Perhaps it’s not as bad in other modes as the acceleration is more gentle.
As I said, just a thought and perhaps DJIs technology is more advanced to counteract this.
Take care. Peter
Perhaps it’s not as bad in other modes as the acceleration is more gentle.
As I said, just a thought and perhaps DJIs technology is more advanced to counteract this.
Take care. Peter
MikeyMikeOZ
Well-Known Member
I actually just noticed this same phenomenon yesterday on my MP! I was flying at 20 foot altitude with switch in P. Maintained course. Got a mile out, turned around, switched to sport, and full throttle back to me. Return flight was supposed to be the exact same course and altitude.
I was following a straight line on the ground. The flight out was very straight with minor corrections to the sticks in relation to the line i was following.
The flight back I noticed a slow decent, 20, 19, 18, 17 feet. Also, I had more noticeable corrections to the AC in correlation to the line I was following.
I chalked this up to the fact of being in sports mode, and the and AC making quick headway (double the speed).
The "line" I was following was railroad tracks. I know many of you will say it was the tracks fault and tracks induce MAG interference and compass errors and this and that. Not to discredit anyone who makes those claims, but I fly near tracks all the time and only notice those ill effects if I take off too close to the tracks.
Sorry for the long post, and my intention was not to hijack the OP's thread, but rather post my story as well.
I was following a straight line on the ground. The flight out was very straight with minor corrections to the sticks in relation to the line i was following.
The flight back I noticed a slow decent, 20, 19, 18, 17 feet. Also, I had more noticeable corrections to the AC in correlation to the line I was following.
I chalked this up to the fact of being in sports mode, and the and AC making quick headway (double the speed).
The "line" I was following was railroad tracks. I know many of you will say it was the tracks fault and tracks induce MAG interference and compass errors and this and that. Not to discredit anyone who makes those claims, but I fly near tracks all the time and only notice those ill effects if I take off too close to the tracks.
Sorry for the long post, and my intention was not to hijack the OP's thread, but rather post my story as well.
If anyone did suggest that, they would be incorrect.
Unless you fly very, very close to railroad tracks, they will have no effect at all on your drone.
And if they were to have any effect it would be on direction rather than altitude.
Flying above railroad tracks won't pull your drone downwards.
This is a "me too" post. I have a MP and have noticed that on low level flight (~20 feet) that it will lose altitude over flat terrain yet continue to report the original altitude. The most recent example occurred while practicing a point of interest flight using myself as the point of interest. I was on flat terrain the starting altitude was 25 feet and all I was doing was circling while keeping me in the center of the display. After three quarters around the copter was only at head height but still reporting being at 25 feet. I regularly calibrate both the IMU and the compass. Any thoughts as to what might be happening here? Thanks.
Personal Drone Repair
Active Member
Hey guys , it's just physics .
The steeper the forward angle is , the less thrust is under the unit .
Drag caused by the added forward speed combined with the small loss of vertical thrust will cause this .
Notice the angle of a spoiler mounted to the rear deck of a race car . Exact same physics at play with drone on Sport mode . High Speed . Steep Pitch Angle .
Do your thing .
Just be aware of this characteristic and plan for it .
The steeper the forward angle is , the less thrust is under the unit .
Drag caused by the added forward speed combined with the small loss of vertical thrust will cause this .
Notice the angle of a spoiler mounted to the rear deck of a race car . Exact same physics at play with drone on Sport mode . High Speed . Steep Pitch Angle .
Do your thing .
Just be aware of this characteristic and plan for it .
Although I understand the physics here, I am a bit concerned that the telemetry continues to report the original height even though the quad is physically half the original height. Makes me wonder what is happening to the reported telemetry when the quad is flying above 200 feet. Seems this suggests an issue with the downward sensors or the IMU. Any thoughts?
Personal Drone Repair
Active Member
That is possible . I have not heard of too many issues arising from the on board hardware though .
Just a theory . It could be possible that the mobile system is not responsive enough to read register and report in real time at say any where from 40-50 mph .
Purely theory .
You do have my interest peaked . A high altitude controlled test would be good info to acquire .
Pop up to a safe height , say 400 ft . Give the girl Sport mode , pitch full forward , and just see if the telemetry tries to report the discrepancy at all . I know that it would be hard to judge how far off the readings were , but it would good to know if the system even tried .
At 400 ft. , you would have plenty of time and safe room to perform a visual assessment .
Either which way , the test would be fun .
That sounds like the barometer sensor is drifting during the flight.
In POI the drone will maintain a constant altitude but if the altitude data from the sensor is drifting, the drone doesn't maintain a steady true altitude.
Personal Drone Repair
Active Member
Woops.
Just read your original post ChipDorm .
Probably should have read it before I addressed your issue .
Just read your original post ChipDorm .
Probably should have read it before I addressed your issue .
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