On Friday, June 5, 2020 at 1:26:21 PM UTC-4, wrote:
Good and cheap are mutually exclusive. A good, safe machine won't be cheap.

Right, but I thought the idea of the original question was to see if sacrificing some good (higher than 300 foot tow?) might make cheap and safe possible.

Seems like a small corner case until there are lots more FES, but still fun to think about.

Agreed! It's a fun thought experiment for a growing sector of the sport.

For me, the issue is that if I have a setup which can get me to 300', it can get me a lot higher for minimal extra effort. 300' would mean about 600' of linear space, which is unlikely to fit in the area before a runway. So once I'm using any part of the runway, I might was well use the entire length.

From a mechanical perspective, the only substantial difference between 300' and 3000' is the length of rope and the total energy required. The angles, forces, and power stays the same.

Some crucial distinctions of a 100' long catapult-style launch are that there's no hardware on the runway so it can plausibly be completely autonomous; the angles are purely horizontal so the spooling system is simplified and the hook cannot drift down onto the runway; a 3 second launch means that motor cooling is not an issue due to the thermal mass of the motor; and a launch failure is very graceful, with a worst case result of rolling down the runway at a leisurely 30-40kts.