Finding a Lost Quad

It was the first trip to the in-law’s farm after getting my HX100, and I was looking forward to trying it out where I had lots of open space. I’d already had a good set of flights with my Acrobrat flying all of the packs I had, before switching over to my HX100 and having fun with that one.

On my last pack for the HX100, I decided to see how far it could go given the lower power VTX, and flew it out to the edge of the empty field I was using.

You can see the line of darker green between the treeline to the right and the stand of trees left of center.

I got all of the way out to the stand of trees and backed to fly along the edge of the corn field next to the empty field I’d been flying over. The video signal was having a little bit of an issue but so bad that I couldn’t fly it. Still I didn’t want to push my luck further and possibly lose it in the corn field, so I turned back towards where I was flying from.

Looking back towards where I was standing, along the edge of the green field towards the right quarter of the picture.

Only a few seconds after turning back it failsafed and crashed. The impact tilted the camera up so the top half of the view was the inside of the canopy and the rest was some plants.

Totally not realizing some of the limitations of the receiver on the HX100 versus the one on my Acrobrat, I headed out into the field with the range check on my radio turned on so I could find it by playing a little game of hot and cold. I’d done that before when crashing my Acrobrat in a different spot and it had worked great. There was a big problem with my plan though that I didn’t realize until later. The FrSky receiver that came on the HX100 quad did not support telemetry, which is important because telemetry is how the radio displays a range strength value. So I was wandering around in this field looking at a zero number that wasn’t changing, and assuming it was because I just was too far away and not that it would never not be zero even if I was right on top of the quad. It wasn’t until I got to the edge of the corn field which I knew was well past where the quad had crashed that I finally realized my mistake.

I turned of my radio at this point and instead tried studying the video feed in my goggles to see if I could tell where the quad was. There wasn’t much to go on though, unless I got very lucky and saw myself walking by.

After a couple of minutes though the video feed cut out, and the battery had been totally drained. This was the point when I first thought I might not be getting the quad back. I was standing in the middle of a large farm field with no idea how to locate a nearly brand new microquad.

At this point I had two issues to deal with. First, I was well overdue to be back at my in-law’s house for lunch after which we were supposed to be heading home. Second, I had no idea how I was going to locate the quad. This was bad as beyond just losing an expensive piece of electronics, I was sure my father-in-law wasn’t going to want to have that sitting out in his field and then getting tilled under at some point and leaching into the soil. There’s a lot of stuff used in electronics that you don’t want in a soybean or corn field.

I drove back to the house and first let my wife know I wasn’t going to be able to leave just yet. Then I grabbed my tablet and an SD Card reader so I could more easily review the DVR recorded from the quad than I could from my goggles. I was hoping something in the video would help me locate it. Lastly I drafted my sons to come out and help me search.

I drove back out to the field I’d been flying with my search party. I watched the tail end of the flight video several times and thought I knew generally where it should be, so we started to hunt around in that park of the field but had no luck after several minutes. After looking at the video again, I finally realized I was misreading the tree line in the DVR video from right before the crash. It wasn’t the stand of trees at the east end of the field, but a gap in the treeline along the south part of the field where a gas line was buried. I had been looking in the wrong place all along and taken my search party back to the same spot and continued to look in the wrong spot. My oldest had actually been asking me about that other treeline after watching the video over my shoulder. He was very excited to be right.

The actual useful frame from the DVR before the crash with the gap in the treeline.

Once we started looking in the right part of the field, we found it pretty quickly. That actually surprised me, as I figured it would take some luck to see it among the ground cover that had been planted, but the black canopy and blue props stuck out pretty well from the brown and green.

I made a lot of mistakes trying to find my quad. I should have realized that I didn’t actually have telemetry on the quad. I should have had the tablet out with me from the start in case I needed to review the DVR. I also had made a mistake the week before when configuring the quad. I had turned off the setting in Betaflight that would cause the motors to beep when the receiver loses connection to the radio. I hadn’t ever needed it before since I’d rarely lost the receiver connection and could use the radio to turn on the beeping manually if I needed help finding it in the grass. I turned it off though because it was beeping whenever I plugged in a battery while it was connected to USB in order to make a VTX change without having my radio on as well. So one of the first things I did when I got home was turn that option back on.

Failsafe Crash Clip
Full Flight

Not a Yard Flyer

At this stage in my FPV journey it’s May and I’ve finally gotten my 3″ build back together on a new frame with all of the broken components replaced. Now the primary reason why I went for a build with 3″ props was because I’d heard that anything smaller than that didn’t really fly as well as a regular 5″ quad, but I didn’t really have the perspective at the time to understand what that meant for what I was actually looking for.

My yard is about two tenths of an acre, or just over 800 square meters, in size, and while not tiny it turns out is too small to fly a 3″ build in. Or at least too small for someone who’s just stepped up from flying whoops with brushed motors to a much larger quad with brushless motors. To illustrate what I mean, my AcroBee whoop weighs 30 grams with a battery, and my Acrobrat clocks in at 260 grams with battery, which is about half a pound. I can’t quantify the difference in speed involved between the two but it was very significant. So just like I started out the hard way by learning to fly indoors, I misjudged the amount of quad I needed for yard flying as well.

I tried addressing this by adding a throttle cut in my transmitter. This is a way of reducing the throttle by a percentage so that giving the maximum throttle on the stick would only have the quad go at say 90% of it’s real maximum. I gave 75% a shot first, then 60% and then 50% before I started to feel more comfortable. Even then, with the louder motors and the heavier weight, I just wasn’t comfortable flying the yard when my kids were out playing or there were neighbors outside. Hitting someone with a whoop won’t normally hurt given the light weight and prop guards, but hitting someone with a half pound inertia and 3″ spinning plastic blades would cause some damage.

Fortunately my kids’ elementary school is nearby and the grounds are open on the weekend. So I as able to make a few trips over there to fly the parking lot when it was empty. But that was just enough of a taste of getting to fly a bigger and faster quad, that it made flying the whoops around the yard on weeknights not as fun. So I started researching again to see about some of the smaller options for 2.5″ and 2″ quads to see what there was that would work better for me to be able to fly in the evenings after work where I wouldn’t have to drive anywhere.

This summer a new class of micro quadcopter known as a Toothpick designed by YouTuber KababFPV became very popular (he’s a dentist which is where the name came from). These were small quads with very light, usually about 70 grams, carbon fiber frames with 2″ or 2.5″ props. As this type of build started to take off, it seemed like it fit what I was looking for pretty well, but I struggled to find a good frame I liked and figure out what motors and other parts I needed.

Then in late August Is saw a review for BetaFPV’s HX100 and thought maybe that was worth giving a shot. It’s not a perfect build. I don’t like the way the VTX antenna in the back comes out even with the props, but the weight and size looked good so I thought I’d try it out.

Flying a toothpick-style quad in my yard was a completely different experience from my Acrobrat right from the start. It’s about 72 grams with a 500 mAh 2S battery, so about twice as heavy as a whoop instead of 8 times as heavy. It would still hurt if I hit someone with it but I don’t think it would cause any injuries, and hopefully I never have occasion to find out. With 2″ props on it and 1103 motors, it’s not nearly as loud either, so I don’t worry about flying it when my kids are out playing or there’s a lot of traffic in the neighborhood.

So the HX100 has been the perfect yard flyer for me. From August on I started keeping half a dozen 2S batteries charged so I could go outside after dinner and get in about half and hour of flying around the house whenever the weather permitted.

In hindsight it makes sense that what I was looking for in a yard flyer isn’t really what most people were talking about online when they were talking about smaller quads. I think I was just a few months ahead of the curve as the whole microclass of quads personified by the toothpick design has really exploded in the last few months. I just didn’t know then what kinds of questions I should be asking and I didn’t have any frame of reference to evaluate the information I was finding. Which is part of the fun of the hobby for me, it’s a constant learning experience.