Universally Safe RTH Practice

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Just for everyone's peace of mind and to protect our expensive hobby gear, I'd like a discussion on widely regarded safety practices for return to home/launch (RTH). Perhaps this could eventually get stickied by the mods once the content is reviewed by many seasoned Solo owners.

disclaimer: try everything here at your own risk...other members are not responsible for suggestions found within this thread.

Obviously this depends on flying style and locations (built-up areas vs wide open space). Let's establish some safety setting parameters for the average user flying line of sight (LoS) assuming a mix of both environment and will not be adjusting it pre-flight each time (set it and forget it).

Officially:
I believe RTH info from Solo's release is outdated, the best reference is in this link:

Return Home | 3DR | Drone & UAV Technology

Instead of giving absolute statements, they decide to go with different scenarios. I think this needs crystal clear explanation from the community.

If I understand correctly, before RTH your Solo will:

- climb 10m/34ft if above RTH altitude, regardless of cone zone?? (CZ is the radius around home/launch point which is 1/3 of your RTH altitude in length)
- climb a measely 2.5m/8ft if within CZ and below RTH altitude
- climb to RTH altitude or boundary of CZ (whichever happens first) if outside CZ and below RTH altitude

Considerations:

1. Increasing RTH altitude also increases CZ. This could be more ideal or less ideal. Ideal because there's more clearance height in general but at the expense of your now-wider CZ. I've set my RTH altitude at 40m/130ft so CZ radius is 13m/43ft. This RTH altitude should clear your average tree, powerline and 10 storey/level building.

2. in Orbit, fly a higher altitude than your target's height so there's enough clearance and your Solo won't slam into said target should your controller lose signal. This is assuming one isn't using Tower nor is able to walk around the target.

3. When taking off from on a cliff/hill/rooftop etc, always fly outside of CZ before decending below launch point so your Solo won't slam into the cliffside/hillside/building-side etc. should your controller lose signal.

4. Probably the most important: keep a constant watch on vital stats (duh) and always be prepared for wifi/GPS signal loss. clear obstacle path for wifi loss and assign fly:manual to a custom key for GPS loss and get comfortable flying in it with practice. Try not to panic!

all inputs welcome. I want to have a solid understand of this instead of just inefficient flying relatively high at all times.
 
Last edited:
I've never worried about it. Around here nothing is above 200 feet, so I have RTH set at 225. Works fine.
 
the kb is accurate and everything you describe is correct. i think the scenarios breaks it down in a manner that anyone can digest. the smart return home concept is complicated and 3dr managed to simplify it with those 3 scenarios.

as part of my pre-flight checks i always verify rth alt based on the current surroundings. i adjust as necessary because there are times when i will definitely be out of the cone zone and i want to restrict solo to a certain height if rth is invoked.
 
today I tried testing the different cases listed on the KB, I couldn't replicate Case #2 within home cone and rising 2.5m...it would rise to RTH

So unless my Solo is not performing to specs...the KB is likely outdated, heads up everyone.
 
in general I like the RTH and other failsafe features with one exception :

when in Follow me mode (not the "look at me follow") I can't think of many advantages of having Solo to return to launch point as a failsafe. In all situations that I tried the Follow me mode (so far) I would always prefer Solo to attempt to land where my current (or last known) location is (in case of loss of signal for example) because that would in most cases always be somewhere near me, rather than flying back to start point some 3-4km away with 20% battery left.
yes, I can think of situation when I would prefer Solo to return home (launch point) to "dry land" in Follow me mode when following me on the boat for example or if I was performing follow me on a busy street with traffic
but I would just like to have this as an option in settings to choose myself and when using Follow me in open cross country terrain I would always like to fly with RTH failsafe disabled (and replaced with "return to operator's current or last known location").
 
pretty sure that's coming in boat mode...

anyone else test their Solo to see RTH behavior when in cone zone? Does it climb to RTH altitude or just raise 2.5m?
 
pretty sure that's coming in boat mode...

anyone else test their Solo to see RTH behavior when in cone zone? Does it climb to RTH altitude or just raise 2.5m?

I had a situation in Follow "look at me" mode where Solo is hovering in stationary position and camera followed my car that I was driving, I left Solo hovering above the launch point (more or less, perhaps 5m away from launch point) for safety because I thought there was a great possibility of loss of signal since I was driving up and down between crests and hills, so I thought well if I lose signal, Solo will have an easy job to return home.
Yes, I lost the signal and when I returned the Solo was exactly where I expected it to be, sitting on the ground exactly where I launched it, but when I reviewed the video later I was shocked to learn how Solo got there :
- it seemed to climb up only little bit (perhaps those 2.5m), then it descended to about 0.5m above ground and only from there it traveled at this altitude to its launch point where it finally landed. If there was any obstruction or uneven terrain it would've crashed.
 

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