First crash. Telemetry help?

[AH-1G]

"The expert @Ty Pilot" I know him personally. If you need to know about the H+ flying capabilities and shooting fantastic cinematic video, he's the go to expert! Oh, he's also very humble so he may not take the credit I posted?

 

[Eslader]

I'll report as soon as I know something. We're socked in with weather currently so it'll be a few days. And yeah, I was thinking more like 100 feet up.

 

[Steve Carr]

I'll report as soon as I know something. We're socked in with weather currently so it'll be a few days. And yeah, I was thinking more like 100 feet up.

If I understand your waypoints correctly they would appear as the red diamonds in the pic and your first flight in black. When you fly the route it would be something like the red line with the curved approaches to the waypoints. The curve is going to be similar whether it is horizontal or vertical. I suspect you have correctly identified the reason for hitting the ground.

 

[Eslader]

Yep, the right hand picture is exactly how they were set. 7 and 8 are at the same place horizontally, but in the vertical profile there's about a 240 foot climb from 7 to 8, and your red path on the right looks pretty much exactly like what it did .

Do you think I'm right in thinking that if I had inserted a waypoint (6.5) shortly before 7, at the same altitude as 6 and 7, that it would have flown at the same altitude from 6 to 6.5, and then done a very small downward curve between 6.5 and 7 and therefore not have impacted the ground?

 

[Steve Carr]

You would need to test it to know for sure, but speed may affect close waypoints.

 

[moodman]

That's very valuable information. Yes, it should have been heading to the center of the field after rounding the last corner. The KML file makes it look like it straightened out and was heading for the opposite end, but that's not what I recall seeing in person - it was, from my perspective, curving toward its run to the center.

I hit the gear switch miliseconds before it crashed, foolishly hoping I could get it down in time to shield the camera since at the time I thought it was completely out of control. I should have hit the stop button or the mode switch. Bad piloting on my part.

With all the input I've received here I'm heavily leaning toward it curving itself into the ground to round out the vertical turn for the center-field climb. The weather is going to keep me grounded for the next few days but as soon as I get a chance I'll hover-test it to be sure it's still airworthy, and then I'll do some steep vertical CCC work at higher altitudes to see if it dips down in a similar waypoint setup.

I really appreciate everyone's input. Thanks very much!

I had a crash very similar to the one that you just reported. I asked for some help here in this forum from the telemetry files and it's clear as I could find it was an issue with a prop. my theory is that one of my props actually broke in flight, and that caused it to go into 5 motor mode which made The Craft fly out of
control. Good luck.

 

[Eslader]

Weather cooperated enough to get some testing in today. I've confirmed it was CCC mode and a Bezier curve that caused the crash:



The first spike is setting the CCC list to mimic what I had done when it crashed, only at a higher altitude. I brought it manually down from the final, high waypoint and then started the sequence just before 13:03:54. The sudden dip after the short straight is when it was dipping below the two waypoint's altitude to curve the line. The level section after the dip is because I canceled CCC mode at that time to simulate what I would do if it were close to the ground.

I also tested what would happen if you inserted a waypoint shortly before the waypoint where it was supposed to start the climb. So, moving from waypoint 1 to waypoint 2 at the same altitude, then waypoint 3 right next to waypoint 2, also at the same altitude, then a climb to waypoint 4 directly over 3. It flew level from 1 to 2, and then very sharply dipped downward a few feet between 2 and 3 - so it still did a curve, but the drop in altitude was much smaller:



You can just barely see a sudden dip right before the climb. So that's a good lesson learned: Do not make sudden climbs in CCC mode from low altitudes or you are likely to curve the path right through the ground.