Curious Behavior 3DR Considers Normal

[AKPilot]

I had my first incident with Solo yesterday. It started with a casual flight. Preflight went well and had GPS lock in <1min like usual. As I ended my flight I decided to use the RTH function. Solo was about 8 ft AGL whe it started to rapidly fly towards a tree trunk. I quickly hit pause then started to try and adjust course manually. It 'fought' my stick control and wouldn't allow me to move it to where I intended to land so I set it down before it headed for some shrubs. As soon as it touched down it immediately did a lightning fast flip landing on it's back trashing the props until about 3 seconds later when it shut down. Where I had to set it down had a slight incline.

I sent the logs and the above description to 3DR support. The replied that:
"Checking the GPS coordinates were the vehicle is being flown, it looks like a pretty good location, except for the trees behind the takeoff/land point. See, the trees can significantly lower the dilution of precision of the GPS and create multipath errors, causing the vehicle to drift or move unexpectedly during GPS depended modes. Due to lack of GPS reliability this is not fully considered a vehicle failure..."

The closest trees (spruce) were 35 feet to the south. Some low alder to the west which no longer have leaves and you can clearly see the horizon through them and are only about 15-20' tall. Nearly unobstructed northern view. Single story home 50' away is the only potential obstruction to the east. In other words, there really isn't much in the way of obstruction and I don't have any issues with GPS lock. It really doesn't get any better unless in a wide open field which is pretty rare where I live. It seems average or better than many areas in videos I see people post.

The flip seemed to be due to landing on slight incline because I could hear the motors give a burst right as it touched down. I really like Solo but am contemplating returning it since I have had it less than 30 days. I have a few questions that maybe others can help me with.

Is this normal behavior for Solo to fight control significantly more if it has a degraded GPS signal? Does it not default to manual mode if it doesn't have a adequate GPS signal to hold position? Without GPS is it really that difficult to fly? Does it do a flip due to trying to correct itself on an uneven landing and if so, how can I correct for this since I can't gaurentee pavement smooth landing pads? Should I take off and land without GPS? (this opens up a whole new discussion on how to use all the GPS dependent modes sometime after takeoff) I have experience with quads but none with GPS and even my $50 Hubsan isn't that hard to fly and definitely won't flip if landing on less than perfectly level land. Is there a way to have the throttle stick completely power down the motors without delay like on most flying craft?

I've flown quads, helicopters, and planes too and except for gassers, which throttle down to the point of no lift, the throttle stick would allow shutting down the motors. I've also flown Solo in manual and other modes to see how the different modes behave and didn't have prior difficulty. I consider myself an adequate pilot to handle the situation Solo was in.

The only mod I have done is the GPS insulator. I didn't have problems before but while I had Solo open for routing the HDMI cable I did the mod.

I tried to upload the tlog but for some reason the forum won't allow me. If a visual of where my launch and landing was the GPS coordinates are 64.917087, -147.645007. Draftlogic.com has the best rotating arial photos of this area.

Any help with this would be greatly appreciated and please don't turn this into a "this drone is better than that one" thread. I think Solo is a great platform but just may not be fore me or maybe I need to understand its behavior better in less than ideal circumstances.

 

[Area25]

I agree that the GPS shouldn't have a problem where you flew. My issues have been many I consider myself an experienced flyer. If I wasn't the many saves I had to fly out of due to either GPS loss or Wifi would have seen the Solo in bits. While 3DR may consider that for there Solo the GPS is fine it is not what other UAV's suffer from in my experience. I can fly my DJI Phantom2 v.2 almost anywhere and the Solo can't even come close to being able to fly where I can fly either the Phantom or Iris. So, who's fault are all the problems the Solo suffers from? Surely not the buyer. While 3DR has been trying to create a functioning UAV it is the buyer who is ultimately taking it on the chin. I've read this forum for months and sat on the sideline while my Solo has sat in my office as I don't dare fly something I have no faith in. If others on this forum are happy to problem solve and be the 'test pilot' throwing darts at the wall to solve there problems then that is fine as it's there decision. Personally, my plan is to make an epic video as I crash the Solo into tiny bits. I see no other use for it.

 

[AKPilot]

I posted this for assistance answering some questions or giving advice on Solo's flight behavior. The first response I get answered none, gave no advice on Solo, and started the comparison game. I know there are other options out there. Each have their pros and cons. This was posted in a Solo help forum for a reason. The more we learn and solve things the more the entire community benefits.

 

[Acroduster]

Addressing your questions:

"Is this normal behavior for Solo to fight control significantly more if it has a degraded GPS signal?"

Solo has only done this once to me, and it did indeed fight control.

"Does it not default to manual mode if it doesn't have a adequate GPS signal to hold position?"

Apparently, it does not. It appears that as the signal weakens and the fix has more variability in
it, it just tries to get to the position it thinks it should be. "A" button Fly:manual is your friend here.

"Without GPS is it really that difficult to fly?"

With a little practice, not at all. Someone of your experience should have no issues, the biggest
of which is getting orientation right when you're flying toward you.

"Does it do a flip due to trying to correct itself on an uneven landing and if so, how can I correct for this since I can't gaurentee pavement smooth landing pads?"

This phenomenon hasn't been common in the forum. I have landed and taken off from slight
slopes with no issues. If the slope is more than 5 degrees or so, I'd try planting it - touching
the high-side gear, then down and to the left with the throttle to shut it down.

"Should I take off and land without GPS? (this opens up a whole new discussion on how to use all the GPS dependent modes sometime after takeoff)"

Many here advise that you do not use GPS below 10' AGL. You can get GPS lock before
take off and still take off manually. This lock will be used for the RTH point. Once you get
above 10' AGL, press the Fly button and you will have full access to all GPS dependent
modes.

"I have experience with quads but none with GPS and even my $50 Hubsan isn't that hard to fly and definitely won't flip if landing on less than perfectly level land. Is there a way to have the throttle stick completely power down the motors without delay like on most flying craft?"

By taking off and landing in manual mode, it will react like your Hubsan, although because this
one is heavier and more sophisticated, it will probably be smoother.

Hope this helps...

 

[Acroduster]

Oops - to finish answering your last point - I do not know of an instant way to shut down the motors. Stick down and to the left is probably the quickest, although there is a slight delay. The emergency A + B + Pause button has a built in delay because it's a pretty drastic measure and if you're up in the air, the aircraft will plummet to the ground.

 

[Solo58216]

I had a similar problem including the "operating with in normal prams" And that it looked like the trees could have been a problem from 3DR. When I replayed the flight in mission planer it showed a "compass error" during the crash.... And looking through the prams list (I think thats where I saw it) it looks to me like it takes 5 seconds before a loss of anything results it turning over to manual flight. Got to say mine covers a scary distance at full tilt in 5 seconds.

 

[Maddog]

AK- I disagree with 3DR. I think this is a clear failure of the Solo's systems, and the crash is Solos fault not yours.

 

[User Name]

AK- I disagree with 3DR. I think this is a clear failure of the Solo's systems, and the crash is Solos fault not yours.

I would have to agree, and I think it does more harm to 3DR to deny this than to replace a set of props. While I haven't personally run into any issues like this, the GPS in the Solo is definitely weak. I seem to average 8-10 satellites on the solo, even on the top of a mountain with a clear view of the sky. I built a little 250 from random parts, and I almost always see 16-18 satellites in more obstructed areas. I'll probably look into replacing the stock GPS receiver with the N8 (which is what's in my little 250).

I do think it's a good idea, and I just started today, to get comfortable flying in manual. It's just as stable as Fly mode, with the exception that it'll drift in the wind and will coast when you let off the controls - it won't automatically come to a stop and hold position. Aside from that, it's honestly hard to tell you're not in Fly, if anything, it's smoother since it's not always trying to stop itself when you lower the inputs.

I've always relied on RTL to come back and land, and it's always worked, but like manual, I think it's probably a good idea to let RTL bring the Solo back and down, and switch to manual for the last 20 or so feet of the descent. I can understand that GPS quality will do down near the ground, but it wouldn't be an issue if the receiver itself provided a more robust signal in the first place.

I'd still argue the point with 3DR. There was a case not too long ago where they initially said the same thing "not Solo's fault", but then offered to cover the damage under warranty.

In the end, I think it's best to take marketing claims with a grain of salt. The Solo is very advanced, and very easy to fly, even for a total beginner. But that assumes perfect conditions, and perfect conditions can change, and it's always going to be better to rely on skill and have the automation be there to help, as opposed to relying on automation and hope it works perfectly from takeoff to landing.

 

[jmeyer7526]

This happened to me on my first flight, thought it was my error and 3dr said the same.being new in I figured I did something wrong but could have sworn I lost control, first quad but been in rc with cars for years. Now this happened to me 2 more times at low alt, and I know for a fact I tried to pause and manually control but it did not respond to my commands. I think k it is a glitch but I am not a techie.

 

[Acroduster]

Again - instead of hitting pause (which requires solid GPS to work correctly), set your A button to manual and hit that.

 

[AKPilot]

Addressing your questions:

"Is this normal behavior for Solo to fight control significantly more if it has a degraded GPS signal?"

Solo has only done this once to me, and it did indeed fight control.

"Does it not default to manual mode if it doesn't have a adequate GPS signal to hold position?"

Apparently, it does not. It appears that as the signal weakens and the fix has more variability in
it, it just tries to get to the position it thinks it should be. "A" button Fly:manual is your friend here.

"Without GPS is it really that difficult to fly?"

With a little practice, not at all. Someone of your experience should have no issues, the biggest
of which is getting orientation right when you're flying toward you.

"Does it do a flip due to trying to correct itself on an uneven landing and if so, how can I correct for this since I can't gaurentee pavement smooth landing pads?"

This phenomenon hasn't been common in the forum. I have landed and taken off from slight
slopes with no issues. If the slope is more than 5 degrees or so, I'd try planting it - touching
the high-side gear, then down and to the left with the throttle to shut it down.

"Should I take off and land without GPS? (this opens up a whole new discussion on how to use all the GPS dependent modes sometime after takeoff)"

Many here advise that you do not use GPS below 10' AGL. You can get GPS lock before
take off and still take off manually. This lock will be used for the RTH point. Once you get
above 10' AGL, press the Fly button and you will have full access to all GPS dependent
modes.

"I have experience with quads but none with GPS and even my $50 Hubsan isn't that hard to fly and definitely won't flip if landing on less than perfectly level land. Is there a way to have the throttle stick completely power down the motors without delay like on most flying craft?"

By taking off and landing in manual mode, it will react like your Hubsan, although because this
one is heavier and more sophisticated, it will probably be smoother.

Hope this helps...

Thank you for the time put into your reply.
I have flown it manual to see how it handles without GPS and you are right, Solo is MUCH easier to fly than others I have flown. It was so easy that for some reason I thought GPS might still be on and I misunderstood the different modes.
I just set my A button to Fly Manual. Great idea!
I didn't think about taking off in manual, hitting Fly once airborne, then return to manual when landing. I feel comfortable landing it myself and living with pilot error as a crash instead of losing control and just watching what Solo 'wants' to do.

 

[AKPilot]

AK- I disagree with 3DR. I think this is a clear failure of the Solo's systems, and the crash is Solos fault not yours.

For the record 3DR is sending me new blades and I didn't even have to ask for them. Even if there is a disagreement with where the fault is I think 3DR has excellent customer service to offer replacement blades without a request.

 

[jmeyer7526]

Again - instead of hitting pause (which requires solid GPS to work correctly), set your A button to manual and hit that.

I understand the pause part but why not controls with the stick.... I tried to use those to recover and no reponse.

 

[AKPilot]

I do think that if I am following directions from 3DR in having a clear view of the sky, having great GPS lock before flying and returning on a flight path that has no less clear view of the sky, then if there is a crash due to GPS errors then it is Solo's fault. I was 35' from that tree when I took off and flew no where near it when returning.
If I don't find any more injuries and they send me some new props then I guess it really doesn't matter.

Thank you all for the advice.
It's looking more like I need to fly manual more (way more fun anyway) and use GPS when I'm trying to get some smooth, more automated video. I wish there was a more in depth technical manual. I feel there is a lot going on inside Solo and 3DR marketing felt buyers just want to push Fly, sit back, and watch.

 

[AKPilot]

I understand the pause part but why not controls with the stick.... I tried to use those to recover and no reponse.

I hit pause to interrupt the RTH and immediately began to use the sticks for control. I did not know that the GPS was causing the problem at the time. I like the idea of immediate manual mode. This probably would have avoided the problem and I could have landed it exactly where I wanted.

 

[User Name]

I wish there was a more in depth technical manual. I feel there is a lot going on inside Solo and 3DR marketing felt buyers just want to push Fly, sit back, and watch.

Copter | Multirotor UAV

Get ready for your brain to hurt! This is the documentation for basically the same flight controller the Solo uses. Solo uses a Pixhawk 2, which specific information is slim on, but it's basically a Pixhawk with the added automation the Solo has (smart shots, etc.).

It'd end up being a chunk of money depending on how much gear you already have, but if you really want to learn, there's no better experience than building your own quad. I built a little 250 (250mm from prop shaft to prop shaft), and have it controlled by a Pixfalcon (www.pixfalcon.com basically a mini Pixhawk). I'm learning all the inns and outs of setup, flight modes, autonomous flights, etc. while not risking the investment in the Solo. If you have a standard RC transmitter, you could build a small quad for $250-$300, or under $200 if you wanted a flight controller with lesser capabilities.

As an added bonus, being so much smaller, the 250 is much more skittish than the Solo, so if you get accustomed to flying it, even in Manual, the Solo seems like it's on rails in comparison.

 

[Maddog]

For the record 3DR is sending me new blades and I didn't even have to ask for them. Even if there is a disagreement with where the fault is I think 3DR has excellent customer service to offer replacement blades without a request.

Ahh- I was under the impression they just told you "too bad, so sad. Your problem not ours".

I'm glad they sent the props out!

 

[nuggetz]

This happened to me and was my only crash to date. I hit pause on a RTL when Solo was maybe 8 feet off the ground and the trees affected GPS and it started to drift. I had PAUSE on the brain that day because the previous flight taught me to appreciate the PAUSE button. On that previous flight I hit RTL and it looked like Solo was going to overshoot its home location. Looking up at Solo when its 100 feet in the air always looks like its going to blow right past the home position. Anyway, I panicked and hit manual and Solo drifted over some trees due to the wind and I almost lost complete sight of it. I should have used Pause to get my bearings but instead I used manual. So next flight I used PAUSE like a fool and had a very minor incident. Nothing broke luckily.

I suppose I could think of a situation where you wouldn't want manual to kick in fast though it seems like it may have helped both of us. Lets say your near some tree tops or something. If Solo went into manual without warning then it could start drifting outside your line of sight and you'd be staring at an empty sky with a terrified look in your eyes I guess I would prefer a bit of wonkyness as an indicator that something is going wrong so I could intervene with Manual mode. Always pay attention to that HDOP value and number of satellites. I think they should make the font for those things much bigger and more prominent on the app and the controller.

 

[Solo58216]

Last night I brought it in for a landing and paused about 2 feet off the ground. 10' bushes to my left and 150' trees to the right. It started drifting left so I applied max throttle it shot up above the bushes drifted over them. Then back to the correct location all by its self. I then landed with out pausing, with out a problem.

 

[erikgraham]

The closest trees (spruce) were 35 feet to the south. Some low alder to the west which no longer have leaves and you can clearly see the horizon through them and are only about 15-20' tall. Nearly unobstructed northern view. Single story home 50' away is the only potential obstruction to the east. In other words, there really isn't much in the way of obstruction and I don't have any issues with GPS lock. It really doesn't get any better unless in a wide open field which is pretty rare where I live. It seems average or better than many areas in videos I see people post.....

...the GPS coordinates are 64.917087, -147.645007

hmm. I don't know. I checked out the location, even did a 3D sweep and it looks to me like there are a lot of trees... and hilly terrain. Tall trees 35 feet away is not that far. Its nice 3DR is sending you free replacement props, but I think they have a valid point in their email.

GPS all depends where the satellites are in the sky (and how close to the horizon they are) and that can change from day to day - even from the beginning of a flight to the end. That being said, I take off from places like that all the time. On take off I pretty much rocket straight up to get some height and get a better GPS fix. On landing I'm ready to switch into manual, but try not to. Manual can be tricky if its windy, but personally I find it better than having no control (which is the case when GPS gets wonky). Remember, its pure GPS with no assist from cell towers or wifi base stations. So there is a pretty big margin for error, especially low to the ground.