Gordo and Bruce are pioneers in the gliding world. One of their coolest flights that shows their creative flight planning shows up in their 3000km flight in the Sierra Nevada's, and the build up to it.
Some basics: The major challenge in flying gliders is the inherent stochasticity in the weather system. Think of it as a contextual bandit problem with high variance w.r.t local weather (i.e. Even the best planning cannot help if the weather doesn't comply). We have some observability due to forecasting tools (skysight.io) and any policy must have affordances for pilot skill and a margin of safety. A good pilot (or 'policy') starts with multiple plans, quickly modifies to plans to suit the environment, and can seamlessly switch between plans. The primary "reward signals" are duration of flight, distance covered, and (in competitions) hitting certain waypoints.
Previous WR's for longest flight were mostly in the Andes or Alps. You want to be in a mountain range to utilize either the [ridge lift](https://en.wikipedia.org/wiki/Orographic_lift) of a mountain face or [mountain wave](https://en.wikipedia.org/wiki/Lee_wave), ideally in a polar region during the summer to maximize the daylight hours so you can fly under VFR for longer.
However, while the Sierra Nevada's have great mountain wave and ridge lift, the number of daylight hours is not ``competitive''. Their main innovation was in acclimatizing themselves with using night vision goggles for long duration in a glider. There's an article on this [here](https://magazine.weglide.org/gliding-at-night-breaking-the-3...) which describes the acclimatizing flights and the 3k km flight in great detail. It doesn't get official recognition because the FAI requires the flight to be done in daylight, but still an extremely cool flight!
Slightly meta-level: I'm glad the authors finds the ICLR reviews useful, and this illustrates one of the successes of ICLR's policy of always open sourcing the reviews (regardless of whether the paper is accepted or rejected).
The authors benefit from having "testimonials" of how anonymous reviewers interpreted their works, and it also allows opens the door to people outside of the classic academic pipeline to see the behind the scenes arguments to accept/reject a paper.
The force at the attachment point is constantly changing and depends on several factors.
- the weight of either airplane.
- the performance of the engine on that particular day (varies by altitude / airspeed / temp / mixture / type of fuel / ...)
- the instantaneous weather conditions
- the performance characteristics of either plane.
- slack in the rope (no tension to two times the weight of the glider)
- the glider's towing position (below / above wake)
- crosswinds
- the glider's preferred towing position (depends on visibility from the cockpit, e.g. if someone has a phone or a tablet on the dash, the towing position will be different)
So it isn't really a trivial problem, especially when false positive or false negative will lead to a crash.
notice how he's always on the stick. Also notice how fast it goes from stable to unstable positions.
> even a crash
Recklessness is never the answer in aviation (or coding matter of fact). Practically, good luck convincing insurance to cover a 100 ton (any appreciable cargo load) plane that might fall out of the sky on any property in the general vicinity.
In gliding, tow upsets are pretty common and, in rare cases, can be fatal. An out-of-position glider out can _easily_ and very quickly overcome the tow planes elevator authority (ability to pitch up or down) which leads to accidents like this. This video does a good job explaining explaining the root causes and potential dangers (https://youtu.be/5cpqFzhM9dY?si=J7GxP1dI9Xopy3xu). Also read the comments from testimonials from other glider pilots.
This is my biggest concern with this concept as well. Towing things is challenging because the tow plane's center of gravity can change drastically depending on the forces on the glider it is towing -- if the glider deploys its spoilers / crabs in a crosswind / gets in your wake turbulence you're not going to be able to predict how it changes your CG (and your control authority) without training or experience. Also, with gliders, the tow plane is traveling at around 60MPH to 90MPH, with a decision window of 2-3 seconds. Commercial planes travel at ~500 MPH... The concept seems like a hard sell to the pilot unions. I bet they've thought about this though.
Some basics: The major challenge in flying gliders is the inherent stochasticity in the weather system. Think of it as a contextual bandit problem with high variance w.r.t local weather (i.e. Even the best planning cannot help if the weather doesn't comply). We have some observability due to forecasting tools (skysight.io) and any policy must have affordances for pilot skill and a margin of safety. A good pilot (or 'policy') starts with multiple plans, quickly modifies to plans to suit the environment, and can seamlessly switch between plans. The primary "reward signals" are duration of flight, distance covered, and (in competitions) hitting certain waypoints.
Previous WR's for longest flight were mostly in the Andes or Alps. You want to be in a mountain range to utilize either the [ridge lift](https://en.wikipedia.org/wiki/Orographic_lift) of a mountain face or [mountain wave](https://en.wikipedia.org/wiki/Lee_wave), ideally in a polar region during the summer to maximize the daylight hours so you can fly under VFR for longer.
However, while the Sierra Nevada's have great mountain wave and ridge lift, the number of daylight hours is not ``competitive''. Their main innovation was in acclimatizing themselves with using night vision goggles for long duration in a glider. There's an article on this [here](https://magazine.weglide.org/gliding-at-night-breaking-the-3...) which describes the acclimatizing flights and the 3k km flight in great detail. It doesn't get official recognition because the FAI requires the flight to be done in daylight, but still an extremely cool flight!