What's the legal authority permitting "seagliders" to carry passengers but escape aviation regulations? Or to use navigable waterways at high speed when other maritime users are severely restricted in speed? I doubt any historical exceptions would stand up to significant use.
What's the real benefit? Actual ground effect is strong but very, very limited - to about the width of the wing. The (wallowing) demo flight is well above ground effect. Also, the demo's downswept wingtips provide a lot of the "ground effect" benefit.
Most importantly, all of this could be done more cheaply and reliably with internal combustion engines. Why hasn't it already been done, if the demand is so strong?
Sorry, but the technical and legal loopholes seem way too small to thread.
No loophole nor exceptions - we're following guidance from the International Maritime Organization on the maritime regulation of Type A WIGs (https://wwwcdn.imo.org/localresources/en/OurWork/Safety/Docu...), which have been upheld by flag states all around the world.
The benefit of ground effects are:
- 10-20% range extension (agreed, between 50% and 100% wingspan, which is where seagliders fly, the aerodynamic benefit of ground effect is reduced compared to near surface flight)
- Drastic reduction in reserve fuel. This is a key limitation of electric aircraft because they need to sustain powered flight to another airport in the event of an emergency. We can always land on the water, therefore, we can count all of our batteries towards "mission useable"
These two effects combine to give seagliders double the range of any electric aircraft - 180 miles with existing battery technology.
We use hydrofoils to solve for the wave tolerance and maneuverability problems that plagued past WIGs and made them commercially unviable. To take-off directly from hydrofoils before they cavitate, we had to slow take-off speed to ~50 mph, which drove us to a "blown wing" design that distributes propulsion over the wing, "blowing" the wing with high speed air and therefore creating high lift even at low speeds.
Very difficult to distribute propulsion with IC engines or mechanical linkages. Electric propulsion technology unlocks the blown wing, which unlocks the use of hydrofoils, which unlocks wave tolerance and therefore operations of WIGs, which unlocks longer range of electric flight. It all works together.
And electrification is generally good: both for the planet and for ticket prices
Doesn't the landing make a huge impact/force on the foils? I would think that they are designed to make the craft go up, thus more susceptible to it going down at higher speed?
Both landing and take off should be akin in terms of force encountered by the foil unless you're landing over speed or with the craft at an angle respective to your trajectory or the water current. The foils look motorized which is likely the biggest concern compared to static foil designs.
In addition to the other points mentioned, an electric propulsion system has many fewer moving parts than an IC system, less vibe as well and less harsh thermal considerations. There are no fluids to replace or maintain or plumb through the vehicle (no leaks to chase either), so reliability is arguably increased and its also an easier system to maintain.
What's the real benefit? Actual ground effect is strong but very, very limited - to about the width of the wing. The (wallowing) demo flight is well above ground effect. Also, the demo's downswept wingtips provide a lot of the "ground effect" benefit.
Most importantly, all of this could be done more cheaply and reliably with internal combustion engines. Why hasn't it already been done, if the demand is so strong?
Sorry, but the technical and legal loopholes seem way too small to thread.