Well, I figured out the hard way why you should always have a prearm and arm switch. I went out to do a little testing and tuning by my house with the OWL. It was cold outside so I set up while sitting in the truck. I plugged the battery in I was all set and ready to get out to sit the quadcopter on the ground. I jumped out of the truck to sit the quad down to start this tuning session then realized that one of the props looked to need tightening up. I jumped back in the truck sit the quad on the console to unplug the battery and tighten up the prop. When I slid into the truck as I set the quad on the console I hit the disarm switch! Needless to say the quadcopter was in angle mode. It was rolled back a little with a slight pitch to the right. This made the props spin up high enough that it would have flown away if not for my hand, the seat and door panel. I what felt like slow motion hit the kill switch which probably took a couple seconds at least. The shock of the whack to the finger then the flight into the passenger’s seat and door panel. The first thing I thought after I had killed it was “well how many fingers am I missing?” My pinky finger was throbbing! The finger next to it was stinging a little. I kept looking for blood to be coming from somewhere. Thank God nothing was bleeding but it bruised my pinky along the outside middle knuckle. It must have just slammed my pinky into the finger next to it to make it sting. The truck seats did not fare so well. The props and leather do not go very well together. It chewed the top back of the seat up really good along with the door panel.
If I would have had a prearm switch set none of that would have happened! Needless to say, after the shock wore off I flew a few packs but I unplugged the battery anytime it was near my hands. Once I got home I mapped a prearm switch in BetaFlight so this will not happen again. You can see from the video below it was only armed for a couple seconds but man what that would have done had my fingers been down in the props or worse yet if it would have flown into my chest instead of the passenger seat. I have always had respect for these drones they are not really toys. I think anything that can go 80 MPH with props that are rotating at 20,000 rpm should be handled with care. I just thought I was doing a good job at that until this happened. You can bet from now on I will have a prearm and try to only have the battery plugged in when about to fly or picking it up to unplug it.