So, a little backstory. I am sure some of you will remember my post where I was testing the RTH function when the battery reaches a critically low level and the RTH function is triggered. I learned that it is a situation you want to avoid or there is as good chance you, or more appropriately, your 520, will be screwed. My test resulted in loss of control, due to my false belief that the RTH function can be aborted by any control input, which will bring the 520 to a hover if you immediately release whatever input you gave the 520. I am not sure how I came to believe this but it doesn't work, as I found out. Short story is the 520 responded erratically to my control inputs until it made contact with the roof of my house, rolled down the "V" where 2 roof lines intersect, and contact the sidewalk, inflicting serious bodily injury to the 520 and the E90 camera. I have worked on the 520 a few times and felt comfortable repairing the 520. Initially I thought the camera was not damaged save for the UV lens that shattered while protecting the camera lens. If you are flying without a UV lens or otherwise protecting the camera lens I would respectfully suggest you reconsider. With the 520 repaired I realized that the camera would not function normally and soon figured it had some more serious issues than a shattered UV lens. The camera was sent to JOhn at Yuneec Skins who farmed it out to a very talented person who had the knowledge and expertise to return it to like new condition save for a few cosmetic scuff marks.
Fast forward to mid September in Vermont. The fall foliage colors were busting out all over and a friend of mine and I decided to do some flying on a beautiful clear, sunny day. He also flies a 520. I had flown the 520 a few times since I had got it flight worthy so I was looking forward to having some fun getting pictures of the changing fall colors. We alternated flying our drones. Upon returning to land on my second flight I noticed that the right landing skid did not come down when I lowered the gear. I cycled the landing switch. I don't recall if the right side came down until the second or third attempt.I turned the 520 over and cycled the gear several times. Each time it performed as expected.
Returning to land upon completion of the next flight the right side again would not lower and cycling the gear several times did not cause the right side to get with the program. It now became a question of getting the 520 on the ground with only the left gear lowered. I gave Larry the controller and he flew the 520 low enough for me to grab the lowered left strut. At that point Larry attempted to shut down the prop motors but was unable to do it regardless of what he tried. Ultimately, believe it or not, Larry set the controller down, I held onto the left strut, and he reached in from below and popped out the battery. When we flipped the 520 over the gear would recycle properly as many times as I tested it. Wondering if there was some unidentified damage from the roof encounter, I replaced the right landing gear mechanism. I flew the 520 a few times subsequently with no issues, until 2 days ago. The weather was beautiful and I decided to get some pictures of the neighborhood and the lake. The first flight was uneventful from a pilot point of view. The second flight appeared to go equally as well, until I returned for landing and realized the right landing strut would not come down.
I was able to get my wife's attention as she had just gone inside. When I tell her what I want her to do she thinks I have lost my marbles. Becky places the requested 55 gallon barrel that we keep in the garage to collect the water and soda bottles to be recycled at the end of the driveway. I flew the 520 with the left side of the gear retracted just over the top of the barrel and then attempted to descend into the barrel. The prop arms acted as the landing gear, contacting the rim of the barrel. The camera was protected inside the barrel. I left the video recording throughout the landing. The issue was that I was unable to shut down the prop motors. The power toggle was retarded completely as soon as the prop arms contacted the barrel rim. Additionally, I pressed the start/stop button. There was some bouncing around and I opted to fly the 520 off of the barrel. The same thing happened on the second attempt. I am not sure what I did differently the 3rd time but the props shut down. Incredibly, there was absolutely no damage to the 520 or the recently repaired E90. As before, when I turned over the 520 and cycled the gear, both sides worked properly the 10-12 times that I tested it. The offending right side is not getting hung up on anything.
So I am looking for comments on several fronts.
1. The landing gear mechanism is pretty simply. Contacts on the landing gear mechanism touch contacts within the body of the 520 and you are good to go. If the landing gear is properly positioned in the 520 the contact between the body and the landing mechanism is guaranteed. The gear worked properly since I replaced the right gear mechanism, including a flight immediately before the flight in question. Thus, I do not believe it is a power issue. Could this be a software issue? I have not done the recent update the popped up on my controller as that would be another variable - unless tis is a recognized problem and an update resolves it.
My other question revolves around the landing gear in general and how, or when, it functions. Can you shut the props down if the landing gear is up? A mechanism to prevent this from happening would be the easiest explanation for what I experienced. Typically when I land, I ****** the throttle completely when the skids are on the ground. The 520 shuts down pretty quickly. I do not use the red start/stop button to shut down. I thought that maybe with the gear up the props won's shut down by retarding the throttle but will if the start/stop button is depressed. I thought I did both actions pretty much simultaneously. My sense was that when I released back pressure on the throttle because it wasn't doing anything, the 520 started to fly without any power input. Unfortunately I have no idea what I did no the third attempt to get the props shut down.
Any input would be appreciated. Unfortunately, at this time I have a 520 that I consider unreliable. The 520 is a backup for drones on a technical rescue team and for the state USAR team that I am a member of. I have taken it off line as I do not consider it a dependable piece of equipment at this time.
Thanks for taking the time to read this and thanks in advance for your input. It is appreciated.
At least I got some pictures! The 520 "repositioned" itself after it shut down but you get the idea.
Fast forward to mid September in Vermont. The fall foliage colors were busting out all over and a friend of mine and I decided to do some flying on a beautiful clear, sunny day. He also flies a 520. I had flown the 520 a few times since I had got it flight worthy so I was looking forward to having some fun getting pictures of the changing fall colors. We alternated flying our drones. Upon returning to land on my second flight I noticed that the right landing skid did not come down when I lowered the gear. I cycled the landing switch. I don't recall if the right side came down until the second or third attempt.I turned the 520 over and cycled the gear several times. Each time it performed as expected.
Returning to land upon completion of the next flight the right side again would not lower and cycling the gear several times did not cause the right side to get with the program. It now became a question of getting the 520 on the ground with only the left gear lowered. I gave Larry the controller and he flew the 520 low enough for me to grab the lowered left strut. At that point Larry attempted to shut down the prop motors but was unable to do it regardless of what he tried. Ultimately, believe it or not, Larry set the controller down, I held onto the left strut, and he reached in from below and popped out the battery. When we flipped the 520 over the gear would recycle properly as many times as I tested it. Wondering if there was some unidentified damage from the roof encounter, I replaced the right landing gear mechanism. I flew the 520 a few times subsequently with no issues, until 2 days ago. The weather was beautiful and I decided to get some pictures of the neighborhood and the lake. The first flight was uneventful from a pilot point of view. The second flight appeared to go equally as well, until I returned for landing and realized the right landing strut would not come down.
I was able to get my wife's attention as she had just gone inside. When I tell her what I want her to do she thinks I have lost my marbles. Becky places the requested 55 gallon barrel that we keep in the garage to collect the water and soda bottles to be recycled at the end of the driveway. I flew the 520 with the left side of the gear retracted just over the top of the barrel and then attempted to descend into the barrel. The prop arms acted as the landing gear, contacting the rim of the barrel. The camera was protected inside the barrel. I left the video recording throughout the landing. The issue was that I was unable to shut down the prop motors. The power toggle was retarded completely as soon as the prop arms contacted the barrel rim. Additionally, I pressed the start/stop button. There was some bouncing around and I opted to fly the 520 off of the barrel. The same thing happened on the second attempt. I am not sure what I did differently the 3rd time but the props shut down. Incredibly, there was absolutely no damage to the 520 or the recently repaired E90. As before, when I turned over the 520 and cycled the gear, both sides worked properly the 10-12 times that I tested it. The offending right side is not getting hung up on anything.
So I am looking for comments on several fronts.
1. The landing gear mechanism is pretty simply. Contacts on the landing gear mechanism touch contacts within the body of the 520 and you are good to go. If the landing gear is properly positioned in the 520 the contact between the body and the landing mechanism is guaranteed. The gear worked properly since I replaced the right gear mechanism, including a flight immediately before the flight in question. Thus, I do not believe it is a power issue. Could this be a software issue? I have not done the recent update the popped up on my controller as that would be another variable - unless tis is a recognized problem and an update resolves it.
My other question revolves around the landing gear in general and how, or when, it functions. Can you shut the props down if the landing gear is up? A mechanism to prevent this from happening would be the easiest explanation for what I experienced. Typically when I land, I ****** the throttle completely when the skids are on the ground. The 520 shuts down pretty quickly. I do not use the red start/stop button to shut down. I thought that maybe with the gear up the props won's shut down by retarding the throttle but will if the start/stop button is depressed. I thought I did both actions pretty much simultaneously. My sense was that when I released back pressure on the throttle because it wasn't doing anything, the 520 started to fly without any power input. Unfortunately I have no idea what I did no the third attempt to get the props shut down.
Any input would be appreciated. Unfortunately, at this time I have a 520 that I consider unreliable. The 520 is a backup for drones on a technical rescue team and for the state USAR team that I am a member of. I have taken it off line as I do not consider it a dependable piece of equipment at this time.
Thanks for taking the time to read this and thanks in advance for your input. It is appreciated.
At least I got some pictures! The 520 "repositioned" itself after it shut down but you get the idea.