Old footage of test flights of my original glider design back in 2019 (Wichita, Kansas)

It’s extremely difficult to trim. The hardest thing is to get the glider to fly relatively straight at both high and low speeds. Often times, the airplane glides at its cruise speed but the launch at high velocity causes the glider to roll violently or pitch down. My guess it’s aeroelasticity doing it’s magic, shifting the static margin.

It is ultimately a game of balance. The climb has to be perfect, and the plane has to glide at the last third of the flight. This is extremely difficult because in order to get a glide, you need to bend the trailing edge of the wing (elevator) upwards. But if you bend it up too much, the climb will be too steep causing you to lose a lot of initial distance. If you bend it too little, the climb might be just right but you're not gonna have pitching moment to recover and glide in the last third.