Idea: Structured IRIS safety tear-down

We have come across various issues (motor mount screws, short leg screws pushing into motor, Pixhawk/GPS vibration coonnection) with IRIS since the consumer version came out. Some of these issues have caused crashes for some people here. Some of us have been spared.

I’m a person who want’s to make sure that something is airworthy before I attach a couple hundred USD of additional equipment on it and bring it up in the air. I need to trust the device before I go on a real flight with it. That’s why I have been holding back, practicing and testing IRIS solely on an open Baseball field at 10m or lower. That’s not really what I bought IRIS for. But that’s just me.

Hoping that some of you are thinking along the same lines and want to make sure that their IRIS is airworthy, how about we do a structured safety “tear-down”. What I mean with this: Let’s go step-by-step through each component that is required to keep IRIS in the air and make sure that it is in the best condition it could be:

Here is a quick rundown of the components that I’m thinking of and some of the issues that I have either seen myself or that other people have reported:

  • Motors:
  • Motor-mount screws too short (Already found a fix)
  • Propeller:
  • Propeller mount unreliable? Propeller coming loose.
  • Power System:
  • Some electronic components not fixated with silicone
  • XT-60 connected seems to be a cheap Chinese knock off, that might break quickly
  • Stock 3DR batteries discharge quickly after 10.5V -> Change Failsafe voltage and action?
  • Flight Controller
  • z-Axis vibrations due to (direct/indirect) contact with GPS
  • RC radio
  • “Ghost” input due to bad pid in controller

Maybe we can extend this to things that are of secondary nature to airworthiness like:

  • Long legs
  • Brake easy on hard landings

Again, this tear-down is not about “pimping” IRIS with lights or anything like that. (Don’t get me wrong, these are great projects). This is about looking at the hardware parts that keep IRIS in the air and make sure we reduce the risk and likelihood of them failing, while keeping IRIS as IRIS as much as possible.
It’s about proactively coming up with failure scenarios and mitigating them before things go wrong.
Think about this as upgrading IRIS to a hardened version.

What do you think? Who is in looking at these components?
Did I miss anything obvious?

i dont see the problem with the prop nuts, whats wrong is not doing a pre flight check to make sure they are tight before you go plugging the battery in.

i havn’t read anything about ghost inputs from the radio, care to elaborate?

only problem i’ve had so far would be the gps touching the wires coming out of the i2c cable and wearing through the insulation of one of the wires.

i just rotated my GPS module and recalibrated everything and went for a quick flight in the backyard, my vibrations are down but that could also be from the new props i just installed, the old ones were getting pretty beat up from the grass, a set of medium legs would be nice to keep the spinning blades above the grass, and they would hopefully be stronger than the long legs.

Yes, medium legs would be a great thing.
I raised my IRIS by gluing small rubber balls to the short legs. See here: … %3A1445744
That raises IRIS by a few cm. Just enough to get the props out of the grass and to place the battery into the battery compartment without picking her up.

With regards to the props: I agree that checking whether the props are tight should be a required pre-flight checklist item. I do that and I haven’t had any issues. Yet you can see in other posts here that there are people who are having issues. Maybe they are doing something wrong, maybe not. I rather take this as an opportunity to make sure that there is nothing wrong with the prop mounts and I learn from what they are doing (right or wrong).
As part of that I have discovered that 3DR mounted different size (thickness) nuts on my prop mounts. One is thicker and due to the shape get’s less “bite” than the other ones. It’s probably still enough, but I don’t want to risk anything. So I’ll get new ones.
Not really an issue or even common problem yet, but something to look out for.

For the “ghost” input: The Flysky 9X is unfortunately known to have pretty bad potentiometers (See here for an extreme case where throttle out dances while the stick is in the low position: … entiometer for similar reports).
I have had flights, where I didn’t touch the throttle stick at all, yet the logs clearly show input changes. Someone else here (I believe it was njfsu2) reported something similar.
Again, I don’t want to call this an issue yet. Rather an anomaly that I want to investigate further.

Kanga, please move your discussions about DIY modifications to your vehicles to the Iris users group on DIYDrones.

There is no tech support question in this post.