Share your ELEV-8 Crash Stories!

Kyle M.

As many of you know, engineering is very data-driven. Therefore, as I work to improve the ELEV-8, it is extremely helpful to have data to guide design and decision making. To this end, I created a customer survey, which you may have seen in the stickied post on the forums here. However, I'm also seeking some specific feedback about how Parallax's ELEV-8 products have fared in crashes.
So, please feel free to share your crash (or near-miss) stories in as much detail as you want - damage, speed, what you hit, cause, etc. 
I'm looking forward to all the stories - I think we'll all enjoy commiserating over the carnage - and maybe learn a few things.
I'll start (see post below)...

Kyle M.

As is probably the case with most of you, I've got more than a few crash stories, so I'll just stick to the highlights.
Most "famous" is the crash at the end of the ELEV-8 v2 Demo Reel. I was filming a river last summer with a "push" shot away from me. This was about the third take, and I sent the quad a bit farther, and somehow ended up losing directional resolution (I was unable to determine if the quad was moving towards or away from me). In a split second-decision, I made the call to pull a hard left and intentionally crash into the bank, figuring that was better then even a possibility of crashing into the water. At the time, I thought the quad had a near zero velocity towards/away from me, but as is clear in the video, it was actually moving forward very fast. Despite the speed of the crash, the only damage was two broken props. The camera and gimbal were fine - even leveled out after the crash even though the quad was upside-down.
Hardest ever crash was about 20mph into a granite boulder - shattered two props, two motor mounts, and bent a boom. Don't remember exactly what happened that time.
I've also crashed into a (stationary) car, onto flat ground more times than I can think, and once got it stuck in a tree so badly I had to call a guy to get it down. - I share more details if there is interest.

GlassKNees

I was flying my Elev-8 in an area called "The Pit" - a limestone quarry. The owner of the property allows members of the Sun City R/C Club to fly out there - one of the few places available any time day or evening.
Anyway, I let my quad get away from me and like Kyle, lost its orientation. The aircraft was flying away, heading roughly in the direction of a nearby highway. Fearing of letting it get out of sight, I cut the power and let it fall out of the sky. It hit the ground on one of the motors and cartwheeled. The damage was substantial - all props were broken:


Here is a picture of the motor that took the brunt of the crash:


Replacing the motor required essentially disassembling the aircraft in order to get to the wiring. Thinking that there must be a better way to replace a motor without taking the aircraft apart, I experimented with re-doing the wiring from the ESCs to the motor - made them longer and shorted the motor leads. My goal was to get to the bullet connectors by removing the motor from the end of the boom.
But this idea was a bust. I ended up with the bullet connectors in line with the holes where the screws go through the boom to attach the motor mount. Also, I could not push the wires back towards the chassis as the rubber boom mounts got in the way. This experiment also created additional problems that would lead to a later crash - I had a  couple of bad solder joints.
I got the aircraft back together, but had problems with a couple of the motors (#2, #4), spinning slower than the others. Also, the controller had a habit of occasionally resetting itself. Sometimes it seemed to fly okay but every now and then it would suddenly flip over and fall out of the sky.
One day, while flying over my house, the south wind caught the copter and carried it away over a wooded area behind my house. While trying to get it back, it suddenly flipped over and crashed in the woods. My wife and I spent the next couple of days looking for it to no avail. Then on the third day, a construction worker found it - a road was being constructed and a couple of plastic barriers had been set up on the road's edge.  They were about two feet high and spaced apart by three feet or so; my quad laded in between the two barriers and was out of sight unless you walked right up to it!
Fortunately, the weather was good so there was minimal exposure to the elements. But again, I had substantial repairs - the booms had to be replaced as they were slightly bent, but enough to affect alignment and control. I also replaced some bent screws and another motor (bent spindle) and a motor mount. I also discovered a  faulty ESC which I also replaced. After the repairs were made, I found some yaw issues at power up - the aircraft would spin clockwise and I needed to apply left rudder to correct. I had re-flashed the firmware, calibrated the ESC's as part of the repair process, but I Went ahead and re-calibrated the ESCs and that seemed to fix things. I suspect that the spare ESC I used may be flakey, so I've ordered a few more to keep as spares - will swap out that one for a new one. 
Here's the picture of my repaired aircraft:


I bought some red foil from Hobby Lobby as I didn't get the silver foil from Parallax. Here's a video.

GlassKNees

After several trouble free flights, I had an in-flight failure of my V2 Elev-8 - the same aircraft as above, but since modified with an APM 2.6 flight controller/autopilot, GPS, compass and telemetry transceiver. Prior to this crash, the aircraft has flown trouble free and had been a pleasure to fly - stable in breezy conditions and the different flight modes offered by the APM made it conducive to improving my piloting skills.

On Aug. 8 I was flying over a grassy area. I had noticed an unusual nose, seeming to come from one or both rear motors during yaw movements or climbing. I had noticed it on a previous flight, examined the aircraft and didn't see anything out of the ordinary. I thought that perhaps a pro was out of balance. Anyway, it was about 10 - 15 up when all of a sudden I heard something crack or break and the aircraft suddenly pitched over and crashed. I didn't see anything fall off the aircraft as it was falling - it crashed on grass and damp soil - the grass was recently watered:

]



I'm guessing that it hit on the #1 boom as there's dirt/grass on the motor/mount. There is also some mud on the #3 mount and the prop is badly bent. The #2 prop blades separated completely. The GPS mast broke at the base and the flight controller base mount separated from the aircraft. The damage looks worse than it is. I ordered and received a new GPS mast and I've also ordered four new motors from Parallax, which have not yet arrived. I expect that I will have to replace some screws that attached the booms to the chassis. I won't know if the flight controller is okay until I've completed repairs and configure the compass. I have a spare boom in case one is bent - won't know until I begin tearing it apart. This particular aircraft has suffered several serious crashes but I've been ablel to reasily repair it. I expect to do so again this time.

geo_leeman

I was flying taking some atmospheric T,P,RH measurements just after the gust front from a thunderstorm passed. (The meteorology package will be a Servo article soon.) Anyhow, I had done several soundings in pretty decent winds. The last one I punched the throttle pretty hard to climb up quickly, with the plan of coming down slowly. I've noticed that when hitting the throttle hard from a hover, the control can get iffy for a bit. It did get iffy and a huge gust hit. I flipped upside down, but was on the way to recovering. Sadly, the sensor package (in a small cardboard box at the time) was dangling below a leg. It fouled the prop (cutting the instrument up in the process) and I went down from ~13m. In the attached plots you can see the bump in altitude at the end which was the rise and fall. The data cuts out as the drop sliced the package open. Only damage was one broken motor mount and a slightly deformed plastic landing leg by some miracle.

GlassKNees

The motors I ordered to replace those damaged in the crash arrived and I began the task of tearing down the aircraft. The bad news is there was more damage visible after removing the bottom chassis plate:



You can't see it very well from this picture, but the #1 and #3 booms (the front ones with the red mylar on them) are bent and need to be replaced. As I expected, the screws securing the booms to the chassis are also bent and need to be replaced. Here's a picture of the damaged parts:



The motor mounts are okay, and I have a few spares anyway, as well as a spare boom, but I had to order a couple more booms as well as hardware, as I'm running out of the longer screws - they tend to get bent easily. The two rear motors appear to be undamaged, though I won't know for sure until I conduct a test. The replacement GPS mast arrived so all I need is a replacement boom. The AP flight controller looks okay, but again, I won't know for sure until I reassemble the aircraft and perform the accel, compass calibrations.

nightsjudge

dondurmsss = dondurma

GlassKNees

I've repaired the #3 Boom - attached red mylar ans installed a new motor. Next, I need to remove the other two booms from the aircraft, inspect the screws and test the motors.

GlassKNees

Just returned from a week vacation. The booms I ordered from Parallax arrived so I installed the remaining boom and motor, remounted the electronics, and re-calibrated the flight controller: accelerometer, radio, ESCs and compass. I deleted the old flight logs, made sure that the Geofence was enabled and reset the local magnetic variation (-0.030 rad):



I charged up a battery and took it out for a flight test, which was successful. It flies very well again!