THPro with IRS Take off Failure

[hlorenzl]

Hello co-pilots! This is the first time that this has happened. I flew the TH to check it for any defects and also to check how stable it is in low hovering using its IPS.

So I did all the standard operating procedures like preflight checks on the propellers, motor arms, cgo3+, and landing gears. Also I checked the ST16 for hardware response. Once everything was checked, I took off. First flight was OK, I did not bring it up to more than 5 ft as my aim was to only check the aircraft and to see how stable it is using its IPS. Second Flight was still OK. But the third one was the one that failed, and hit me hard.. literally. I had small but elongated bruises on my chest and cuts on my left arm and thumb as it flew directly towards me. I was about 8-10 ft away from the TH and when I took off, it felt heavy at first and the two motors at the back (on the battery side) seems to have responded a little slower than the other four. So it flew from ground to immediate backwards and in a matter of maybe 2 seconds, it hit me. I still tried to control it but it did not respond to the controller. I tried avoiding it when it got really close but I was too late.. Once it hit me, the motors just turned off, st16 alarmed to 5 rotor mode, and then I immediately grabbed the TH at the landing sticks to prevent damage to the craft if it hits ground.

To expound the differences in the 3 take offs:

Take off #1: Bag - craft preparation and checks - controller turned on - controller checks - craft turned on - take off

Take off #2: Craft from air to ground - motors still running - in about 15-20 seconds, I took off again

Take off #3: Craft from air to ground - motors still running - I left the motors running for maybe about 2-3 minutes (definitely not more than 3) - when I tried to take off again, that's where the accident happened.

Any thoughts about my procedure? Has this happened to anyone before? I posted this hoping to pickup a lesson from it and hope for everyone to see and prevent future accidents like this.

Best regards,
HL

 

[biltno]

Hello co-pilots! This is the first time that this has happened. I flew the TH to check it for any defects and also to check how stable it is in low hovering using its IPS.

So I did all the standard operating procedures like preflight checks on the propellers, motor arms, cgo3+, and landing gears. Also I checked the ST16 for hardware response. Once everything was checked, I took off. First flight was OK, I did not bring it up to more than 5 ft as my aim was to only check the aircraft and to see how stable it is using its IPS. Second Flight was still OK. But the third one was the one that failed, and hit me hard.. literally. I had small but elongated bruises on my chest and cuts on my left arm and thumb as it flew directly towards me. I was about 8-10 ft away from the TH and when I took off, it felt heavy at first and the two motors at the back (on the battery side) seems to have responded a little slower than the other four. So it flew from ground to immediate backwards and in a matter of maybe 2 seconds, it hit me. I still tried to control it but it did not respond to the controller. I tried avoiding it when it got really close but I was too late.. Once it hit me, the motors just turned off, st16 alarmed to 5 rotor mode, and then I immediately grabbed the TH at the landing sticks to prevent damage to the craft if it hits ground.

To expound the differences in the 3 take offs:

Take off #1: Bag - craft preparation and checks - controller turned on - controller checks - craft turned on - take off

Take off #2: Craft from air to ground - motors still running - in about 15-20 seconds, I took off again

Take off #3: Craft from air to ground - motors still running - I left the motors running for maybe about 2-3 minutes (definitely not more than 3) - when I tried to take off again, that's where the accident happened.

Any thoughts about my procedure? Has this happened to anyone before? I posted this hoping to pickup a lesson from it and hope for everyone to see and prevent future accidents like this.

Best regards,
HL

It’s a good thing you escaped with just minor injuries
It could have been a whole different story had the machine been two feet higher
Always keep a minimum 20 foot distance
Glad your ok

 

[JulesTEO]

Hello @hlorenzl , you mention you were testing how stable it was using the IPS; what procedure did you follow to test the IPS?

Greetings!

 

[Steve Carr]

There are a few possibilities, but it would be better to see the telemetry. Upload the telemetry and remote file from that flight as a zip file or by adding .txt to the file name.
In my opinion, it's always best to use max throttle to take off and then climb to around 15'. I stay about 30' from the aircraft when it launch.

 

[gwhuntoon]

It's also possible that you took off in Smart Mode and not Angle Mode. The behavior you describe is similar to my own experience when I did that by mistake. One of the problems with taking off in Smart Mode, especially from 8-10' away is that you are within the Geo Fence. When I did this by mistake the drone didn't seem to respond correctly to my control inputs and seemed to drift against my controls. Had I noticed and either switched it to Angle Mode or just let it go, and drift beyond the minimum Geo Fence distance of 26-30' I'd probably have regained control. The manual states a minimum of 30' or 10m take off distance if taking off in Smart Mode.

 

[Ty Pilot]

Any thoughts about my procedure? Has this happened to anyone before? I posted this hoping to pickup a lesson from it and hope for everyone to see and prevent future accidents like this.

Best regards,
HL

HL, glad your not hurt any worse. As Steve Carr mentioned, you should post your telemetry files so they can be looked at for a better understanding of just what happened. In the mean time; if I'm reading correctly - you started up and took off - hovered a moment, landed engines running on ground 15 - 20 seconds then took off again, landed, engines still running for two to three minutes and upon the third take-off - if flew into you. So total run time of maybe four minutes.

How long did you let the aircraft set on ground engines off, before start up and takeoff?

Do you recall how many satellites the craft was locked onto and how many for the controller?

What colors or sequences were the flight mode status lights showing on the H?

 

[hlorenzl]

It’s a good thing you escaped with just minor injuries
It could have been a whole different story had the machine been two feet higher
Always keep a minimum 20 foot distance
Glad your ok

Thanks! Yeah I knew I was too close and normally on a normal outdoor flight, I would not get closer than 20 ft from the drone. But since I was observing for any changes on the drone, I got much closer to observe how it flies. So I was hoping to observe possible changes on how the motors vibrate or the propellers behave. It was not my first time to get close to a taking-off drone so I was a bit confident.

By the way, I was flying indoors that time and also its not my first time to fly the TH indoors. I'd also like to share that if you plan to fly "semi-indoors" or where gps may get a signal at some point, it is better to set the GPS off before you start flying. This is based from my experience wherein I flew at our semi-open garage. I flew inside the garage but when it got a bit near the open area, it probably started to receive signals from the satellites and started behaving erratically. The initial reaction of the drone was to move away little by little from its hovering position then flies fast to where the GPS points it to go. This cost me 1 prop that hit the mudguard of my truck and caused a stuck landing gear. Lucky enough, that was only the damage. But when I turn off the GPS, it doesn't happen. Just don't turn back on the GPS while in midair. I've also seen someone in YouTube, he turned off the GPS to check the max horizontal speed of the TH. When he turned it back on, the TH moved fast like 30 ft from its hovering position before getting stable again.

 

[hlorenzl]

Hello @hlorenzl , you mention you were testing how stable it was using the IPS; what procedure did you follow to test the IPS?

Greetings!

Hi JulesTEO! I believe it automatically gets into IPS mode once there is no GPS before flight. So, either turning off the GPS before flight, or flying indoors where GPS will really not get through would get the TH into IPS mode (that's what I believe). I've also watched a vid from YouTube wherein you have to do something with the ST16 before turning on the motors (like moving the left stick for a specific number of times, if I remember it correctly).

By the way, sorry I forgot to mention on my first post that I was flying totally indoors wherein GPS won't get through. Also, I'd like to put on a side note that it was not the first time that I flew the TH indoors, and I've flown my P3A also indoors so I was a bit confident flying indoors..

 

[hlorenzl]

There are a few possibilities, but it would be better to see the telemetry. Upload the telemetry and remote file from that flight as a zip file or by adding .txt to the file name.
In my opinion, it's always best to use max throttle to take off and then climb to around 15'. I stay about 30' from the aircraft when it launch.

Thanks Steve! However, I couldn't do that indoors. The TH takes off so fast and strong that it makes me afraid it would fly all the way to the ceiling if I flew with full throttle..haha

Regarding the telemetry, I would do that when I get the chance. I am in-and-out of town these days doing things in preparation for the long Christmas break. I'll send it here when I get the remote from home. Thanks again!

 

[hlorenzl]

It's also possible that you took off in Smart Mode and not Angle Mode. The behavior you describe is similar to my own experience when I did that by mistake. One of the problems with taking off in Smart Mode, especially from 8-10' away is that you are within the Geo Fence. When I did this by mistake the drone didn't seem to respond correctly to my control inputs and seemed to drift against my controls. Had I noticed and either switched it to Angle Mode or just let it go, and drift beyond the minimum Geo Fence distance of 26-30' I'd probably have regained control. The manual states a minimum of 30' or 10m take off distance if taking off in Smart Mode.

Hi gwhuntoon! Thanks for the info. I was sure though that I was in Angle Mode, Obs Avoidance OFF, and in full turtle mode.

 

[hlorenzl]

HL, glad your not hurt any worse. As Steve Carr mentioned, you should post your telemetry files so they can be looked at for a better understanding of just what happened. In the mean time; if I'm reading correctly - you started up and took off - hovered a moment, landed engines running on ground 15 - 20 seconds then took off again, landed, engines still running for two to three minutes and upon the third take-off - if flew into you. So total run time of maybe four minutes.

How long did you let the aircraft set on ground engines off, before start up and takeoff?

Do you recall how many satellites the craft was locked onto and how many for the controller?

What colors or sequences were the flight mode status lights showing on the H?

Hi Ty! Thanks for the concern! I will post the telemetry once I get hold of the controller. I am off town today and probably tomorrow until 23.

You've read it correctly, sir! I took off, landed without turning motors off, took off again, and landed again, but without turning motors off longer than the first landing, and on the 3rd take-off, that's where it happened.

On question #1, I did not turn off the motors when I landed (both for the first and second landing). The first take-off was coming from the bag, so it was off. I always leave, by the way, a battery inside the craft even if I travel with the TH in my car. (Is there even an effect leaving the batteries inside the TH when travelling it around?)

On question #2: there were no sats as I was indoors. Sorry I forgot to mention this on my first post. It was not my first time to fly indoors though..

On question #3: It was on IPS mode as indicated by the violet light at the back and the "IPS" characters in violet font at the upper right corner of the ST16.

 

[Ty Pilot]

On that first question, I was wondering if you booted up the aircraft before starting or flying, to allow the satellite registry to build. There have been quite a few discussions that it is good practice to let the aircraft sit while booted up for up to 16 minutes when it hasn't been flown for a period of time. If I go more than a week without flying this is what I do.

Indoors on 2 so okay

The purple light at the back of the H indicates that you were in Angle mode with IPS on which is what I was curious about.

Hopefully the telemetry will tell you what happened.

 

[rdonson]

Hi JulesTEO! I believe it automatically gets into IPS mode once there is no GPS before flight. So, either turning off the GPS before flight, or flying indoors where GPS will really not get through would get the TH into IPS mode (that's what I believe). I've also watched a vid from YouTube wherein you have to do something with the ST16 before turning on the motors (like moving the left stick for a specific number of times, if I remember it correctly).

By the way, sorry I forgot to mention on my first post that I was flying totally indoors wherein GPS won't get through. Also, I'd like to put on a side note that it was not the first time that I flew the TH indoors, and I've flown my P3A also indoors so I was a bit confident flying indoors..