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This video was posted as an answer to another question:

The plane is quite hard to even see due to traveling at a high speed in a tight loop. Is it actually being actively controlled around that loop, or is it just a question of getting the control surfaces to the right attitude then watching the wind accelerate it it round and round the loop?

I can see the wings have been painted in contrasting black and white against a bright orange body, but are there any other techniques or "tricks" to giving the pilot feedback from the plane's position and attitude?

(I'm aware that FPV exists, but it doesn't seem to be used for planes very much compared to drones, is that correct?)

pjc50
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  • Unless you can determine the field of view, it's difficult to evaluate what you would see with naked eyes. Modern cameras have very small sensors, and short focal lengths, so large fields of view. That's why the moon is so small in movies and on photos. Even with a "normal" ratio, you don't see any details you would see with eyes. You can check with your smartphone next night, it will be even smaller. – mins Aug 14 '21 at 21:32
  • I think it would be good if the question acknowledged that this 500+ mph r.c. aircraft is an unpowered glider! Anyway, it is definitely being actively controlled by the pilot-- there is no possible control position that results in fully automatic self-sustaining back-side-of-the-hill dynamic soaring! What sort of amplitude of control inputs are involved? -- that sounds like the basis for another question-- – quiet flyer Aug 06 '22 at 02:23

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This video shows how such a model aircraft is controlled from the pilot's perspective:

The pilot manually controls the plane from launch to landing, and also during the loops he actively moves the sticks to keep the plane in a controlled loop.

Just setting the controls and watching the wind accelerate it will not work, because throughout the loop, the airspeed as well as the relative direction of gravity changes. So you can observe that the pilot pulls up the elevator more to turn out of the tailwind back away from the ridge, and also makes small corrections in roll, pitch (and yaw on some models) to keep the plane in the sweet spot on the slope, preventing it from drifting away as a free flying model probably would.

In terms of "tricks" the pilot is always flying the same circle so he knows where to expect the airplane's orientation and position. What likely is more difficult than sustaining the loops is getting back to the landing site from far out, because the silhouette of the plane can correspond to two different attitudes, like how you can interpret a 2D projection of a 3D cube in multiple ways. Pilots usually overcome this with experience, the last known attitude of the aircraft, or giving gentle control inputs to figure out which way the plane is responding (see https://forum.flitetest.com/index.php?threads/aircraft-orientation-and-overcoming-optical-illusions.64027/).

(FPV is becoming common on other fixed wing model aircraft (e.g. long range or park flyers), but in the case of dynamic soaring it does not seem helpful because you'd repeatedly see blurry ground, blue sky and overexposed sun every 2 seconds.)

txp
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  • Welcome to Aviation SE, txp. Great first answer! – Camille Goudeseune Aug 05 '22 at 17:59
  • You could also mention control rate settings. No doubt at 500 mph the control surface deflections would be tiny. Amazing how that glider can withstand all those G's looping so tightly. – Robert DiGiovanni Aug 06 '22 at 13:56
  • Re "yaw"- are we certain that this aircraft even has a rudder at all? Looks to me like the pilot's left hand is just resting there helping to hold the transmitter. – quiet flyer Aug 06 '22 at 14:06
  • Hi Camille, thanks for the edit! – txp Aug 07 '22 at 11:46
  • Re control rate settings: I'm sure the pilot uses tons of expo or maybe even a rate switch to deal with the different flight regimes, good point! However, I feel like this goes beyond the scope of a basic answer to the question. Feel free to add more detail in a footnote or so though! – txp Aug 07 '22 at 11:51
  • Re yaw: I agree, from the two videos it looks like this particular plane does not have a vertical control surface. Maybe it's common for DSS planes to fly with elevator, aileron and flaps only to save complexity and weight, but am not familiar myself. Have put yaw in parentheses – txp Aug 07 '22 at 11:57