Inconsistant altitude variances

[OldManInWva]

Howdy P4 Flyers.... Question... Has many (or any really) experienced what I would consider severe altitude variances between take off ( 0 feet) and landing?? assuming you land in the same location or within a few feet of.

I just went thru 31 of my 32 flights and noticed that not ONE flight was dead on with a 0 Ft start and a 0 ft end reading. The closest reading was a negative .3 ft

The range is anywhere from a neg 10.5 ft to a positive 34 .8 ft

even had a .5 variance after starting and stopping the motors on the bench with no props and only running for 30 sec.

20 of my 31 flights had variances in excess of 10 ft (pos and neg) of take off when landed.

If everybody else is having these issues and with no concerns I will just write it off as being a normal phenomenon.. but since even DJI tech guys like to use altitude readings to deny technical faults in claims I would like to know if anybody else is seeing the same thing I am with their P4's

Personally anything more than a 1 to 2 ft variance in a 15 to 20 min flight is too much... The Barometer should be a LOT more accurate than that.

 

[GMack]

I'll add, with the sonar and VPS on the bottom I would think it should be better too. When mine shows -50 feet on landing after 20 minutes in the air, that is pretty poor.

All that redundancy with a barometer, GPS, Sonar, VPS, and even a barometer on my iPad Air 2 which could be used on landing for comparison, and it still shows -50 feet - or underground - on landing as acceptable tolerances? Heck, my cheap twenty dollar electronic tape measure with its sonar can do better than that - and in inches.

Maybe the HERO maps are made with DJI products? Can't be good.

 

[Philltayl]

Howdy P4 Flyers.... Question... Has many (or any really) experienced what I would consider severe altitude variances between take off ( 0 feet) and landing?? assuming you land in the same location or within a few feet of.

I just went thru 31 of my 32 flights and noticed that not ONE flight was dead on with a 0 Ft start and a 0 ft end reading. The closest reading was a negative .3 ft

The range is anywhere from a neg 10.5 ft to a positive 34 .8 ft

even had a .5 variance after starting and stopping the motors on the bench with no props and only running for 30 sec.

20 of my 31 flights had variances in excess of 10 ft (pos and neg) of take off when landed.

If everybody else is having these issues and with no concerns I will just write it off as being a normal phenomenon.. but since even DJI tech guys like to use altitude readings to deny technical faults in claims I would like to know if anybody else is seeing the same thing I am with their P4's

Personally anything more than a 1 to 2 ft variance in a 15 to 20 min flight is too much... The Barometer should be a LOT more accurate than that.

Think about 'LOCAL' air pressure changes...........

QFE................not QNH........

 

[OldManInWva]

I don't buy the local air pressure changes, not for that much variance over a small amount of time.... Especially when one of my readings was for a 28 second flight, up 50ft in the air and back down and it shows an 8.9 ft variance..

 

[Stanley]

Howdy P4 Flyers.... Question... Has many (or any really) experienced what I would consider severe altitude variances between take off ( 0 feet) and landing?? assuming you land in the same location or within a few feet of.

It is quite common that the pressure can change by 100Pa during several minutes. That means about 30ft during minutes. It depends on the wheather condition. The wind is especially important.

 

[Philltayl]

I don't buy the local air pressure changes, not for that much variance over a small amount of time.... Especially when one of my readings was for a 28 second flight, up 50ft in the air and back down and it shows an 8.9 ft variance..

Wether you buy them or not, that's what is happening. Nature can be a bit of a *****.......

 

[N017RW]

This would seem to illustrate the limited (to non) use of the Baro for maintaining attitude and level flight.
Seems it may be more for autonomous and RTH references.