Insprie 1 Crashes after second flight
- Thread starter Shane Hann
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What the editor said...
If I remember from my Phantom 1 days, doing a compass calibration was advised only if you moved 15 miles from the location you did your initial calibration from. Back then there was no checking of MOD values via an app, just had to watch the way the Phantom moved on its take off. Having said this, I ALWAYS did a calibration before every flight with the Phantom, never had an issue with it.
Having said that, I have only calibrated my Inspire twice, first time to check that it calibrated successfully when I first got it (didnt fly it after the calibration, was just a systems check), and once again before an actual flight. I ALWAYS check the MOD values before each flight. So far the MOD values have been in spec for each flight and I have not re-calibrated, so far, touch wood (laminated in my case!), I have not had any issues yet, but its early days for me, only 5 flights.
Personally I think that if you are moving big distances from one location to another, then its wise to check MOD values and re-calibrate if required.
This website can tell you the amount of magnetic declination for a specific location.
http://www.magnetic-declination.com/
I agree with The Editor, that if you have a known good calibration, why change it if the MOD values are good?
Having said that, I have only calibrated my Inspire twice, first time to check that it calibrated successfully when I first got it (didnt fly it after the calibration, was just a systems check), and once again before an actual flight. I ALWAYS check the MOD values before each flight. So far the MOD values have been in spec for each flight and I have not re-calibrated, so far, touch wood (laminated in my case!), I have not had any issues yet, but its early days for me, only 5 flights.
Personally I think that if you are moving big distances from one location to another, then its wise to check MOD values and re-calibrate if required.
This website can tell you the amount of magnetic declination for a specific location.
http://www.magnetic-declination.com/
I agree with The Editor, that if you have a known good calibration, why change it if the MOD values are good?
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I've heard the opposite of this as well, that you SHOULD always re-calibrate. Is the consensus then, that this is not necessary?
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+1
I have almost 100 flights most all trouble free. I would say I have calibrated maybe 3-4 times. I've probably flown in 8-12 different locations.
I can't understand all the problems associated with the compass, and the requirement to be on specific MOD values.
I've flown different aircraft types and a compass is just a compass, a device which tells you where earth's magnetic pole is.
Depending where on earth you are located, there is a different magnetic declination, and GPS (or even a paper map) can help you find that value (shouldn't be so sensitive to metals around, etc).
And even with a complete compass failure, in no way should it interfere with the capability to remain airborne and under control. You should only loose your reference to the north pole (and maybe some sync to a map, but GPS and IMU can help with that).
I've flown different aircraft types and a compass is just a compass, a device which tells you where earth's magnetic pole is.
Depending where on earth you are located, there is a different magnetic declination, and GPS (or even a paper map) can help you find that value (shouldn't be so sensitive to metals around, etc).
And even with a complete compass failure, in no way should it interfere with the capability to remain airborne and under control. You should only loose your reference to the north pole (and maybe some sync to a map, but GPS and IMU can help with that).
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I've never written the flight control like is used in the Inspire 1, but if all you have is GPS and IMU w/ Faulty Compass readings, I can't see how you (the flight controller) would know where you're pointed. So, if you're just trying to hover and stay at your current position and lets say the wind bows you off course. In order for you to take a corrective action you would need to know where the front of the AC is pointing before you could even begin to react. One of the major sensors in any IMU is the compass. Without it you have no reference on anything solid, only rotation in all the axes since the last reading.
So, I can see totally how a flight system like is in the Inspire would go nuts trying to stay on course or even hold position.
Losing your compass in a normal AC that YOU are inside and flying/controlling is a whole different story than a flight system that NEEDS that reference to know what direction to apply it's controls to adjust for the external forces (Wind) being applied to it.
Again, I have never written a system like this, but software design and control systems is what I do for a living. Not trying to make it overcomplicated, but at the end of the day, it's a pretty complicated matter with a flight control system of this level. If this was simple, we would have had devices like the Inspire back in the 60's and 70's. When you think about it, the flight control system in the Inspire and many other UAVs IS the magic that makes this happen. Everything else is just motors and batteries. All typical stuff that has been around for decades. But the ability to let an unskilled pilot fly so easily is really what has caused the explosion in UAVs.
Thanks for your insights, one day I would like to share ideas with developers like you, as sometimes it seems to me manufacturers could take different approaches.
I don't like the dependency on GPS for example, for short video / photo flights dead reckoning could be an option (when the IMUs are capable of that).
My opinion is that a lot can be made to make ATTI flight easier too, you shouldn't be required to have sub-milimetter precision on your fingers (maybe different modes, like smooth video, sport, etc).
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Keep us posted on your outcome Shane as this is very serious. I've been following many posts about these flyaways and it makes me wonder what's going on. I fly everyday and most of my flights are out over a mile away from me up to and over two miles. Please God, watch over me on this issue since I've had THREE Blade 350 QX's fly away on me, one with a GoPro4, FVP, Carbon Fiber props, Max Amp battery, altimeter and more. I feel you Shane........ Your vender better be behind you on this issue with DJI, I know mine would be. Warranty flyaways should be covered as DJI can pull the "black box" info from your flight and even recover the info from the damaged battery. Post your findings on my youtube channel Shane, this is a big deal for all Inspire owners. This is just a quick link to a wildfire flight I did flying in over 2 miles to get to the fire.
It would be nice if DJI would directly respond to this post and inform us all what the hell is going on.
Do you still hold this belief? I calibrate compass at every location even if I am returning to the same site a day later. It is SOP for me. 70 Flights not a single problem. I flew a test today after the firmware update. No problems at all.
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Personally yes I do, and I shall continue to fly that way.
However, as I have always said, you need to make up your own mind as I did and do what you feel comfortable with.
I do not calibrate everytime for the chance of introducing a skewed result that will not manifest itself until airborne and clear of the anomaly.
That's just my practice though.
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Dronedoctor, I do not want this to escalate into a flaming contest or an argument into whether long range flights should be carried out or not etc but I do have a genuine question for you.
In the instance you site regarding the forest fire, you say you were flying over two miles away to get to the fire. How was it possible that you maintained your Situational Awareness so as to be cognisant of other aircraft (Fire, Police, Emergency Helicopters or News Crews etc) in the immediate area?
If you were hovering in place to get a shot surely your SA would be nil for 266degrees visually and zero audibly?
OK That's fair.
Given how serious a compass problem can become it makes sense to not fix what isn't broken. However everything I have read says Calibrate Compass at new location because each location has its own electromagnetic signature which could affect the compass.
Do you check MOD values before each flight instead?
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Hehe..... you haven't read many of my posts have you? I am the number one person on this forum for championing checking your mod values before EVERY SINGLE FLIGHT (even after swapping out batteries).
If any of my mod values are not right I do not fly that spot
Ya man you even got me to saying and doing it too,but has anyone ever checked their mods and aborted a flight because they were out of range? ?
Or has anyone took off inspite the mods being out of range and crashed ??
I'd like to see a recording of a malfunction when the mods are out of range and one of when they are in range ,so feel free to post that..
until we all start using recording devices I guess we'll never know for sure if checking mods help or are a just a false sense of security. .
turbo. ..
Or has anyone took off inspite the mods being out of range and crashed ??
I'd like to see a recording of a malfunction when the mods are out of range and one of when they are in range ,so feel free to post that..
until we all start using recording devices I guess we'll never know for sure if checking mods help or are a just a false sense of security. .
turbo. ..
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Well I have!
. I have had one instance where my compass mod value was almost 1700. I had not flown that spot before but knew I had a good compass cal from previously. Now I suppose this would be an instance where somebody might calibrate their compass because of a high mod value. I chose not to and moved around 10 feet further away. Put the Inspire down and it was still out 
. Moved about another 20 feet put the Inspire down and.... bam. Mod value back to around 1480-1510. Flew and had no problems. Obviously there was something in the area causing that compass to pull out of spec. I chose that particular point not to fly but was fine around 30 feet away.I will never know what would have happened if I had recalibrated from that original spot other than my compass would have been out by around 200 for that locations declination. This may have caused me problems once airborne and clear but I will never know
Shane, I'm sorry, I was speaking from past experience. When I received my Inspire back from repair, I had to do an upgrade and found out that you are correct, they have changed the firmware to include both the aircraft and controller.
My apologies for the wrong information.
Mark
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I always recalibrate the compass when I arrive at a new location. I believe that this is the correct procedure as it as it enables your craft to firmly establish where it is.
What do you mean by a skewed calibration? And what do you mean by 'but you would never know?'
