Inspire 2 Wreck Inside Industrial Building

[g36pilot]

emtea, since you had a displayed compass error is it possible you experienced TBE, Toilet Bowl Effect? This is caused be the need for compass calibration The craft will fly like its riding a whirling vortex.

It is my understanding that switching to ATTI mode only helps with GPS and VP control input errors. The "compass" is never disabled.

When researching a compass problem I was told that the "compass" function of the IMU cannot be disabled on the I1. I never found a way to do it.

According to the I1 manual pg. 12, the GPS RTH function is available in ATTI with loss of RC signal. Since you had control via the RC and had a compass warning, I think you had a calibration issue with the compass and/or the entire IMU.

 

[Mark Taylor]

It is my understanding that switching to ATTI mode only helps with GPS and VP control input errors. The "compass" is never disabled.

What function do you believe the compass has when you are in ATTI mode?

 

[emtea]

What function do you believe the compass has when you are in ATTI mode?

The Go App still shows which way the bird is pointing, maybe that uses the compass? I don't really know, just guessing. Not sure if it would be used for any other flight use though but a "toilet bowl effect" is exactly what I had, the drone just spun like it was caught in a vortex or wind funnel, like g36pilot said.

emtea, since you had a displayed compass error is it possible you experienced TBE, Toilet Bowl Effect? This is caused be the need for compass calibration The craft will fly like its riding a whirling vortex.

It is my understanding that switching to ATTI mode only helps with GPS and VP control input errors. The "compass" is never disabled.

When researching a compass problem I was told that the "compass" function of the IMU cannot be disabled on the I1. I never found a way to do it.

According to the I1 manual pg. 12, the GPS RTH function is available in ATTI with loss of RC signal. Since you had control via the RC and had a compass warning, I think you had a calibration issue with the compass and/or the entire IMU.

 

[g36pilot]

What function do you believe the compass has when you are in ATTI mode?

A heading reference such as "heading hold". Otherwise when you center a yaw input it will drift.

I'm thinking the GPS is still providing position data if available for map reference and the actual compass heading value in ATTI though GPS navigation inputs are disabled. I'll check on my next flight by switching to Atti and see if the map is still displayed accurately. Pg 12 of the I1 manual states the GPS RTH feature is still available in ATTI leading me to believe this.

Edit to add: ATTI mode RTH feature is available with loss of RC signal.

 

[Mark Taylor]

The Go App still shows which way the bird is pointing, maybe that uses the compass? I don't really know, just guessing. Not sure if it would be used for any other flight use though but a "toilet bowl effect" is exactly what I had, the drone just spun like it was caught in a vortex or wind funnel, like g36pilot said.

The data from the compass may well be used to display the heading in the app, but it isn't part of the flight controls when in ATTI mode.

Standard response to encountering TBE is to switch to ATTI mode, this is why it is a concern for Mavic or Spark pilots as they have no ability to force a swtich to ATTI mode...

You said in your first post that the problem was 'wobble violently back and forth and drifting out of control', that isn't 'spinning' though, so I'm not quite sure which problem you had.. ?

 

[Mark Taylor]

A heading reference such as "heading hold". Otherwise when you center a yaw input it will drift.

I'm thinking the GPS is still providing position data if available for map reference and the actual compass heading value in ATTI though GPS navigation inputs are disabled. I'll check on my next flight by switching to Atti and see if the map is still displayed accurately. Pg 12 of the I1 manual states the GPS RTH feature is still available in ATTI leading me to believe this.

Edit to add: ATTI mode RTH feature is available with loss of RC signal.

Switching to ATTI mode doesn't turn off the GPS or compass, it simply ignores them for flight control purposes.

So if you suffer signal loss while in ATTI mode but you still have a good GPS and compass then it will still use RTH.

Similarly you will still see position and orientation information in the app while in ATTI mode if the GPS and compass are still working...

The IMU provides highly accurate rotational information so it can still stop and hold a direction after a yaw input as it can sense when it is rotating. This is no different to the FBL unit on a heli for example, it has no compass but it can still stop and hold a direction, but without a compass it doesn't know which direction it is actually holding...

 

[emtea]

The data from the compass may well be used to display the heading in the app, but it isn't part of the flight controls when in ATTI mode.

Standard response to encountering TBE is to switch to ATTI mode, this is why it is a concern for Mavic or Spark pilots as they have no ability to force a swtich to ATTI mode...

You said in your first post that the problem was 'wobble violently back and forth and drifting out of control', that isn't 'spinning' though, so I'm not quite sure which problem you had.. ?

If I had to compare it to something, it was doing what a spinning top does as it slows down and "loses balance". I tried to google it and while I don't know how I feel about the music, this is nevertheless illustrative:

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[Mark Taylor]

That doesn't sound much like TBE to be honest.

 

[g36pilot]

That doesn't sound much like TBE to be honest.

Agreed.

Doesn't TBE allow heading hold while making ever increasing radius circles as bank & pitch angles increase? It did on my couple of self induced experiences. 1.) Did not calibrate compass in new area and 2.) Compass calibration over a large power supply cable under what we thought was a clear area. It was intermittently active making diagnosis difficult.

 

[emtea]

Agreed.

Doesn't TBE allow heading hold while making ever increasing radius circles as bank & pitch angles increase? It did on my couple of self induced experiences. 1.) Did not calibrate compass in new area and 2.) Compass calibration over a large power supply cable under what we thought was a clear area. It was intermittently active making diagnosis difficult.

In that case I have no idea what happened or what TBE is. I've found youtube videos of drones and helicopters simply flying smoothly in a spiral (increasing in radius) and some that are doing what I experienced (the violent wobbling motion), all labeled or claimed to be TBE.

 

[fiweli]

Unfortunately we can't choose VPS as a 'mode', we are either in P-mode which will try to use both GPS and VPS, or we are in ATTI mode which will not try to use GPS or VPS.

If we start in P mode with a GPS lock and then loose that lock it will degrade to VPS only, if it determines VPS is useable...

VPS needs good lighting and enough of a pattern/contrast on the floor to maintain a position, so it is not always useable...

So if you use P mode inside and have no GPS lock so you depend on VPS you need to be very sure that you will not pick up a poor GPS lock during the flight as that will mess with positional stability, especially if there is a lot of metal around.

Usually you can't be sure of that so it is safer to start in ATTI mode, so you have to accurately fly the mission, taking special care with air currents (AC) proximity to overhead surfaces etc globalsteelconstruction.fr., but know that the aircraft is not going to start trying to use a weak GPS or a messed up compass at the wrong moment, but of course VPS is not available either in ATTI mode...

The Inspire 2 likely drifted because it lost GPS indoors and switched to Atti Mode, where it can’t hold position and will drift with air movement. The metal environment likely interfered with the compass or IMU. VPS might not have worked due to poor lighting or floor texture. For indoor flights, expect Atti Mode, ensure VPS is on and working, avoid large metal areas, and calibrate sensors beforehand. Use slow, careful inputs and consider a smaller drone for tight spaces.