“Woo hoo!” shouted Phan. His quadcopter lifted off the ground with a smooth woosh and climbed straight up at a good clip. “Plenty power, yes?”
“Looking good, man. But you should probably keep it below a hundred feet what with this being the first flight and all.” I said.
“Is smart.” he nodded, pulling back on the throttle but the quad kept climbing. He pulled the throttle back further to no effect.
“Shut off the radio!” I told him. “Force it into failsafe.” The drone was turning into a shrinking dot, still climbing rapidly. Phan looked dubious, but nodded to himself and flipped the power switch off. The quad was now just a dot in the sky. If we took our eyes off of it we’d probably not be able to see it.
“This is very much a shit.” said Phan, squinting.
“I think it’s coming back down.” It appeared that the dot was getting bigger. We could still hear it making the noise of an angry wasp, but only barely above the noises of the wind, cars on the road, and people in the park talking and yelling to one another. It was coming down though, the dot increased in size and as we watched, we could make out the cruciform shape of the four arms. By shutting off the radio, the autopilot in the quad takes over in failsafe mode. It guides the aircraft to sixty feet above the point of launch and then slowly lands. It’s built so that if it flies too far away and loses contact with the radio, it will “go home.” It’s a safety factor to protect people and property as much as save the considerable investment in the drone.
We stood there, necks craned and our eyes on the sky and watched the little aircraft come down. “I think it maybe is not fly so much as falling.” said Phan. He sounded a bit worried. I didn’t blame him. If it was free falling it was doing so at terminal velocity, the speed at which objects are pulled down by gravity. In common terms, about 124 miles an hour.
We could now clearly see the quad again. The motors were turning and keeping the aircraft parallel with the ground, but it was dropping like a rock. About the time I figured the thing was toast, we heard the motors wind up to full power as the drone attempted to hover at its assigned sixty feet. It came within twenty five feet or so of the ground, and motors wailing like berserk chain saws, it reversed direction and ascended again. At the programmed sixty feet it stopped rising, but began to fly in a circle, kind of like the water in a flushed toilet. As it went around and around, the spiral widened further and further until it was making a circle about 100 feet i diameter. “You suppose to land, piece of shit crap!” yelled Phan. As though it heard him, the drone tipped to the side and dove downward, aiming for Phan. It just missed the ducking Vietnamese R/C enthusiast by inches and then leveled off about ten inches from the ground and shot across the wide park lawn like a skipping rock. Two hundred feet later it drooped down a little, caught a landing skid in the grass and cartwheeled six times before coming to rest on its back. “You suck!” yelled Phan, spittle dripping on his chin.
“That could have gone a little better.” I said. Phan shot me a look that said my sarcasm wasn’t appreciated and walked over to pick up his quad. We looked it over, and except for two broken propellers it didn’t look all the worse for the incident. I pointed to a wire that was hanging loose, its connector unattached to anything. “Maybe that’s the problem.” I said.
Phan looked at it and got a look on his face like he’d sucked a lemon. “Is S bus connection.” he growled. An S bus type system does away with the many small cables that control the roll, pitch, yaw and throttle as well as any other components like camera mounts. Instead, there is a single wire that carries al of the signals over what is called a serial bus, or S bus. Apparently the cable was loose and when Phan pushed the throttle up on takeoff, the wire fell loose leaving it climbing wide open and unable to process any further commands from the radio. Since the failsafe is in the autopilot and not the radio receiver, it was able to work just fine. Except for needing a little fine tuning, it had done a good job.
He set the drone on my lap and headed back to the car. I got the job of carrying the quad because I was on wheels, what with my mobility scooter. At the trunk, Phan pulled out his tool kit and got to work changing out the broken propellers. He plugged the S bus cable back in, and this time he wrapped a tie wrap around the connectors to prevent any of the few wires to come loose. This done, we took the drone back out onto the wide expanse of grass for another try.
The quad lifted off and Phan brought it to hover about 10 feet from the ground. Smiling, he controlled the drone through a few figure eights and then flew a wide circle, letting the aircraft get up to four hundred feet or so away. All in all it was flying pretty nicely. Leaving Phan to fly, I rolled back to the cars and got my own hexacopter out and grabbed the controller and four battery packs. I get about ten minutes of flight time out of a battery, what with the weight it carried. I had a full sized Nikon DSLR camera attached, giving the hex some serious weight to lift. Phan was changing batteries as I got back to the flying area.
He waited while I put my drone through its preflight procedures and then we both took off simultaneously. I kept my drone facing his so I could get video of his quad in flight. We spent about twenty minutes getting what we figured to be about five to six minutes of useful video. We had both just changed to our last batteries and took off when another drone flew into the mix. It was a quacopter similar to Phan’s. We looked around to see who was controllig it and saw what looked to be a kid in his late teens. We shrugged and went back to trying to get video of Phan’s new drone. Every time we had a pretty good setup going, the other drone came buzzing through, causing us to have to reposition again. We were running out of flight time and getting a little annoyed with the kid. I was about to yell at him to give way so we could shoot when the kid started buzzing Phan’s quad and my hex. He would dart straight towards our aircraft and then veer off at the last moment. He came within a couple of feet of my hex a couple of times and that did it for me. I landed my drone and called it a day. I wasn’t going to risk twenty five hundred bucks worth of aircraft and camera.
I rolled over to my drone and picked it up as I watched Phan bringing his quad back towards us. I figured he was landing too. But the kid wasn’t having any of that and started cutting in front of Phan to block his path. Phan tried going up and over and swooping below to get past the kid and his quad. He’d given up and was just letting it descend where it was when catastrophe struck. The kid misjudged his distance and the two drones collided in the air. Pieces of both drones scattered and fell to the ground along with the main bodies of both aircraft. Phan let loose with a machine gun delivery of curses and ran to his crumpled quad. The kid ran over to the wreckage as well.
“You stupid chink!” yelled the kid. “Look what you did to my quad!” I had my drone and controller in the carry box behind my scooter and tooled towards Phan and the kid as fast as the scooter would let me.
“You dumbass, stupid fawk!” yelled Phan.
The kid lunged towards Phan who lifted his foot and stomped on the kids quad. Both of the aircraft could have been fixed, but after Phan stomped the kid’s quad there was no hope. The kid pulled up short and stared in horror as Phan stomped the quad again and then once more, turning it into a pile of plastic shards, wires and chunks of carbon fiber. I doubted whether he could even use the motors given the stomping they took. I had to admit I took a certain pleasure in seeing what Phan had done to the kid’s aircraft, considering the kid was trolling for trouble the way he was flying. The kid looked to where Phan’s quad lay, three props shattered and one of the arms broken. He started towards it, no doubt intending to do to it what Phan had done to his. He got within five feet of his target when Phan delivered a roundhouse kick that hit the kid in his chest. The kid went down, the wind knocked out of him. “Holy shit!” I said.
Phan stood over the kid and yelled at him. I had no idea what he was saying because he was yelling in Vietnamese, but it sounded like he was comparing the kid’s family tree to different kinds of animal dung. The kid held his hands up in surrender. “I’m sorry! I’m sorry!” he huffed. He was just regaining his breath.
“Why you do that?” growled Phan. “Why you have to screw up other people flying? Why you no leave alone?”
“I was just messing around. I didn’t mean to hit you. It was a mistake.” whined the kid. I told Phan it was time to leave it alone.
“Come on, man. Let’s just go. Nobody’s doing any more flying today anyway.” I said.
Phan made a noise like a snarl and bent to pick up his quad. As he lifted it, the weight of the dangling broken arm put too much weight on the motor wires and they separated. The motor and broken arm piece fell to the ground with a small thud. Phan closed his eyes and I could tell he was counting to ten, picturing a quiet place, or considering the risk of jail time. He sighed heavily and picked up the severed limb and walked off toward the cars in silence.
“That was a pretty stupid thing you did.” I told the kid. He just looked at me and said nothing. I shook my head and turned the scooter and followed Phan towards the parking lot. I caught up with him and we moved along together in silence. Phan put his broken quad in the trunk of his car and closed the lid. “I’m sorry things turned out like they did, Phan.”
He shrugged. “So I am too.” he said. “I fix the quad and fly it more in a week.” He didn’t sound convinced but I gave him points for trying to be positive. We both looked back across the parks and saw that the kid was collecting up the pieces of his drone. “He not going to fly next week.” said Phan and he climbed into the driver’s seat. I tapped the fender of his car and swung my scooter around and drove it up the ramp into my van. A couple minutes later I was on my way home.