Flyaway / Failsafe not stopping props

Just performed the second flight test of my newly build quad. F450 based frame, 920Kv motors and 30A ESCs.

Running APM 3.2.1 and the latest version of Mission Planner.

I am controlling the quad via a joystick from the ground station as I have no Tx/Rx as yet.

What happened today was that about 1-2 mins into my flight, I was in a hover at about 2 meters, and upon trying to get back on the ground, I lost throttle response, and the quad started to climb, and I realised I had no control whatsoever from the ground station. I was unable to throttle down or disarm.

After climbing and moving with the wind it hit a neighbour’s roof, and ended up in someone else’s rear garden, on it’s side with the props still spinning against a wall.

Luckily the only real damage to the quad is one broken prop and a couple of missing screws (must get some loctite!).

Upon looking at the logs I can actually see that the APM went into LAND mode after losing the link to the GCS, which is great - else I’d most likely have lost it for good. What does concern me however is why the props were still spinning after at least 20 seconds on the ground spinning against a wall.

Could someone please take a look at my log?

Also it would be good to know why I lost GCS, I was only 5 meters max away from the quad!

You are not really trying to fly a safe setup. Please get a traditional TX before trying again.

How did you have your GCS radio connected? Where was the antenna sited?? Before you flew how far did you get with a range check on the ground? You did do one right?

Hi Gary

Indeed, lesson certainly learnt and the quad is grounded until I get both the GPS module and the traditional Tx/Rx fitted. I was too impatient in this instance.

The radio module is strapped to the bottom of the quad frame, with the antenna pointing upwards. On the ground side, the module is in my laptop’s USB port again with the antenna pointing straight up.

I have not performed a range check, I had not in fact heard of doing one but in retrospect it makes sense. I would not have expected to lose radio with less than 5-7 meters between the laptop and the quad, but lesson learned!

BTW, I think that in this instance the props are not stopping because THR_MIN is set to the default of 130, which is enough throttle to keep the props spinning.