Fell from 50 feet

[cabinfourus]

So the other day, a local rodeo was close to my home. I decided to get some video of the rodeo with one of my Typhoon H drones. After fully charging a few batteries, and doing a quick preflight check, I was ready to take to the air. Everything booted up great, so I started the motors and took off. After flying for about 25 minutes, I needed to bring the H in, and change the battery. While trying to land, the H started to become unstable, going back and forth. At one point, the drone become unsafe due to the flight becoming so unstable. I tried to land, and when I say land, I don't mean bring it to the ground. When I land my drones, I bring it close enough to get my hand on the landing gear, and press the emergency (red) stop button on the remote, to avoid any landing problems. So while trying to land my drone, I lowered the response lever on the remote to the 'turtle' setting, trying to get better control of it. This only made things worse!

To make a long story short, my H finally fell from about 50 or 60 feet right in front of me. The damage, believe it or not, wasn't too bad. I have not pulled the flight logs yet, but plan to later today. I do think I know why it did this. One of my front motor mounts had slid off the carbon fiber arm. Other than this, not much damage came from the crash. I will have to replace my slip ring wiring, since one wire came loose from the barrel.

I probably had 500 flights on this drone, without an issue at all.
Anyway, I just wanted to share the story.

P. S. I did add a line to my preflight checklist. I now check my motor mounts for looseness.
I will post some pics later today, also.

 

[DoomMeister]

The last thing you want to do is set the Rate slider to Turtle position when trying to land. This reduces the amount signal being sent as an output to the aircraft. In a normal landing being in Turtle position can prevent the motors from going to idle after touching down causing the classic hop,skip, and tip over.

See attached document.

 

[WTFDproject]

So the other day, a local rodeo was close to my home. I decided to get some video of the rodeo with one of my Typhoon H drones. After fully charging a few batteries, and doing a quick preflight check, I was ready to take to the air. Everything booted up great, so I started the motors and took off. After flying for about 25 minutes, I needed to bring the H in, and change the battery. While trying to land, the H started to become unstable, going back and forth. At one point, the drone become unsafe due to the flight becoming so unstable. I tried to land, and when I say land, I don't mean bring it to the ground. When I land my drones, I bring it close enough to get my hand on the landing gear, and press the emergency (red) stop button on the remote, to avoid any landing problems. So while trying to land my drone, I lowered the response lever on the remote to the 'turtle' setting, trying to get better control of it. This only made things worse!

To make a long story short, my H finally fell from about 50 or 60 feet right in front of me. The damage, believe it or not, wasn't too bad. I have not pulled the flight logs yet, but plan to later today. I do think I know why it did this. One of my front motor mounts had slid off the carbon fiber arm. Other than this, not much damage came from the crash. I will have to replace my slip ring wiring, since one wire came loose from the barrel.

I probably had 500 flights on this drone, without an issue at all.
Anyway, I just wanted to share the story.

P. S. I did add a line to my preflight checklist. I now check my motor mounts for looseness.
I will post some pics later today, also.

The flight logs are still a good idea. Some of the description sounds a little like the "Toilet Bowl" issue that was once common. And the motor mount may have been a result of the crash, not a cause.

 

[Steve Carr]

My first inclination based on your description is the voltage was too low to maintain stable flight. I have always recommended landing when the voltage is around 14.8 v on the H. If you wait until the voltage is 14.3 there is a high risk of something going wrong: a rapid drop in voltage do to a weak cell; a slight gust in the breeze that requires more power; changes in the landing zone that require longer air time.
One thing to remember about the H. When the flight controller is busy trying to maintain level flight, it ignores the right stick input and the red button. It will somewhat respond to the throttle. That is the reason during a tip on landing you can't recover unless you've already pressed and held the red button.

 

[cabinfourus]

"Toilet Bowl"

I am afraid I have not heard of this one, but it does sound like the characteristics of the flight I was experiencing. Trying to go into a small circle pattern, with back and forth motion.
I have a family reunion today, but I will try to post some pics of the crash. I will also post the log files, just in case someone else has this type of issue.

 

[cabinfourus]

My first inclination based on your description is the voltage was too low to maintain stable flight. I have always recommended landing when the voltage is around 14.8 v on the H. If you wait until the voltage is 14.3 there is a high risk of something going wrong: a rapid drop in voltage do to a weak cell; a slight gust in the breeze that requires more power; changes in the landing zone that require longer air time.
One thing to remember about the H. When the flight controller is busy trying to maintain level flight, it ignores the right stick input and the red button. It will somewhat respond to the throttle. That is the reason during a tip on landing you can't recover unless you've already pressed and held the red button.

This could be the issue as well. I didn't pay attention to the voltage, but the log files should have this info, and now you have me curious.

 

[cabinfourus]

The last thing you want to do is set the Rate slider to Turtle position when trying to land. This reduces the amount signal being sent as an output to the aircraft. In a normal landing being in Turtle position can prevent the motors from going to idle after touching down causing the classic hop,skip, and tip over.

Makes a lot of sense! It had become so uncontrollable, that I thought slowing her down would help. I didn't think of the signal strength.

 

[DoomMeister]

Makes a lot of sense! It had become so uncontrollable, that I thought slowing her down would help. I didn't think of the signal strength.

To really see the effect of the Rate slider just power on the ST16 then enter the Hardware Monitor. Place the Rate slider at Turtle and observe the sticks as you move them to full deflection in all directions. Then set the slider to Rabbit and repeat with the sticks. There should be no difference here.

Now return to the main screen and double tap Volts to bring up the Final Output Display. Repeat moving the sticks with the Rate slider set to Rabbit and monitor CH1 through CH4. Then compare when you set the Rate slider to Turtle.

Throttle on CH1 will be reduced by 40% from 0_50_100 at Rabbit to 20_50_80 when at Turtle.

There will be a similar 40% reduction in output for Pitch and Roll (CH3 and CH2) from -100_0_100 to -60_0_60, and for Yaw (CH4) from -80_0_80 to -48_0_48.

The reduction of control output when set to Turtle is for making video more cinematic. For takeoff and landing it is best to have the Rate slider in Rabbit giving the pilot full range of control to the aircraft.