Bulls eye! The target is small, but if you aim small, you're bound to hit it. As of my last blog, I promised I would share my going technique of twitching thumbs, and since my last blog was four days over a month ago, I have since moved on, beyond the twitching phenomenon that I was convinced would improve my FPV, drone-flying skills. I'll explain why I moved on from my "pet" term by starting with an explanation of the abstract, aviation term: "Pilot Induced Oscillation".
Pilot Induced Oscillation, or PIO, inevitably happens to aviators and more so when an aircraft is inherently unstable. If you dig into the topic of aerodynamic stability, you'll find different types of stability: Static vs Dynamic, and Positive vs Neutral vs Negative. Set these terms up in a scientific matrix, and you'll have a means of describing how every aircraft naturally behaves. Oh behave. As much as I like to write and instruct, the in depth dissection of these terms steers away from my intended topic, and in the interest of making my posts more concise, I'll leave you with a resource written by Colin Culter, Co-founder of Boldmethod.com, to investigate these concepts:
These terms of stability describe the natural tendencies of an aircraft apart from the pilot, that is before the pilot enters the equation, but if you add the pilot and add the concept of reaction time, you'll discover that, regardless of the aircraft's stability profile, the pilot can induce oscillations that mirror the concept of negative dynamic stability. The time it takes for a pilot to compute a correction impacts how far from the intended axis the aircraft diverges. Hence, a pilot's ability to anticipate corrections mitigates this divergence, but anticipation is only half of the solution and the less practical half at that. The more pragmatic half is to "fly small", i.e. use early, less pronounced corrections.
Twitching Thumbs
So why did "twitching thumbs" for a while seem to improve my drone flying? Like the rest of the populace, I have my theories. I theorize in this case that it was because my novice-level reactions were too latent and too large, and by twitching my thumbs back and forth and up and down, especially when it came to the throttle, I suppressed this latency and limited the throw of my gimbals (i.e. it forced me to fly small).
An aircraft landing technique that I learned back in 2004 and a clever application of the technique to my drone flying eased me out of this cramping twitch. The technique is: while landing an airplane, a pilot needs to shift their fixation from the beginning of the runway to the far end of the runway, and hence become aware of the horizon. Looking out, instead of fixating on a target, gives a pilot the detection of change required to make smaller and more accurate inputs. The fruit of this concept as it pertains to quadcopters is obvious, but the application of this focus-shift was the closing bell for me. It was this: to hit a target's bull's eye, look through the target and pick an aiming point beyond the target. No, this doesn't apply to the sport of archery. When I say "target", I mean "gates" or "pylons". In my drone simulator, I found myself naturally fixating on the gate or the pair of pylons I was targeting, and the closer I would get to the target, the less drift feedback I would receive, making my divergences greater and the necessary corrections to fly through the gate that much wilder. Remember PIO? The larger the input, the more likely the pilot is, remote pilot included, to overshoot the required input, and overshooting can lead to un-overshooting, back and forth until there's Loss of Control. And my drone-simulator history is stocked full of digital evidence that supports the existence of LOC.
To double down on this phenomenon of pilot input latency, add computer or transmitter latency, and PIO can be quite challenging and quite frustrating.
Take a Tape Measure
Bringing the horizon into focus makes the necessary course or power corrections more apparent and highlights it when the required corrections are small. If you need proof of this concept, take a tape measure and hold it up in front of your face. Then rotate the tape measure left and right, trying to make it parallel with your line of sight. Because it's one thing to focus on, you can hold it pretty stationary. Now extend the tape of the tape measure away from you, out to one foot, and do the same thing. The extended tip of the tape measure's movement is easier to detect than the angle of the dispenser because the movement of the tip is amplified. Repeat the exercise as much as you need to convince yourself that the farther you extend the tape measure and hence the farther out you look, the easier it is to detect a rotation or deviation and easier it is to hold the device perfectly parallel to your line of sight.
Now, I hear a few literal readers pointing out in my above example that the further the tape-measure extends, the more the tape arches and the more the tape bounces. AHHH! And you have discovered my last tidbit! When your focusing point is correct, you need little to no corrections. "Proof! Show me the proof!" Okay, okay, focus on the tape-measure, the dispensing part, and try to hold the tape motionless, so that the tip doesn't bounce, say at a five- or six-foot extension. Then try focusing on the extended tip to hold it still. Which is easier? I'll admit this is an imperfect illustration, but shifting your focus out to the horizon, or to an aiming point behind your target, will show-and-tell you the inputs you are making, allowing you to calm your panicking and twitching thumb muscles down to the point where you can naturally "fly small".
Keep that drone flying (small),
—Josiah Hutchison
Photo by Falco Negenman on Unsplash
Photo by Brett Jordan on Unsplash
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