Lukas
January 9, 2024, 10:45am
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A lot of people have probably looked into similar idea already. Launch is the most energy intense part of a flight. Hybrid aircraft might become commercially viable soonish. My idea:
A winch, that
Phase 2, power: stays connected and provides electrical power to the plane through a high voltage cable for as long as possible. During this phase the airplane would accellerate as hard as possible.
Phase 3, return: decouples from the plane and returns in a controlled way, using a chute, drone or smth.
A lot of variations are imagineable.
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– Robot landing pad for planes without landing gear | Brad Ideas
– Robotic landing pad gets more serious | Brad Ideas
In 2010, I proposed the idea of planes with no landing gear which land on robotic platforms . The spring loaded platforms are pulled by cables and so can accelerate and turn with multiple gees, so that almost no matter what the plane does, it can’t miss the platform, and it can even hit hard with safety.
Today I learned there is a European research project called Gabriel with very similar ideas. In their plan, the plane has landing pillars which insert into the platform, rather than wheels. This requires retractable pillars but not the weight of the wheels. The platform runs on a maglev track but can tilt and rotate slightly to match the plane as it lands or takes off.
Overall I still prefer my plan – and I have added some refinements in the intervening years.
From the comments:
When I was a grad student (before there was an Internet) in Physics, Professor Wynans at U. Wisc. had a plane, which he outfitted so that he could tether one wing to a pivot in the middle of a field. He took off by taxying and then climbing while still tethered, hence an infinite circular runway. I flew with him doing this once. If power failed before you cast off the tether wire you just glided round and round till you landed. Worked fine for a small craft.
Dr. John Gibson Winans, 52, an air-minded professor of physics at the
University of Wisconsin, was demonstrating last week the first part of
a pet theory: that airplanes should take off and land in...
Science: Circular Take-Off
Monday, Mar. 21, 1955
Dr. John Gibson Winans, 52, an air-minded professor of physics at the University of Wisconsin, was demonstrating last week the first part of a pet theory: that airplanes should take off and land in circles, as tethered models do.
A straight runway, the professor reasons, is fine if it is long enough. But often, even on a very long runway, a faltering engine or iced-up wings can dump an airplane in crack-up territory beyond the airport fence. A circular runway, on the other hand, is infinitely long because an airplane, tethered to its center, can fly around it indefinitely. The pilot need not fear “running out of runway.” Even if his engine dies after the takeoff, his airplane can circle safely to the ground again.
Professor Winans heard that the circular take-off had been demonstrated as a stunt by Jean Roche in 1938. In 1950 Winans got from the Sanders Aviation Co. of Riverdale, Md. the special equipment (a hub, spindle and release gear) that Roche used, but his attempts at that time to take off in a circle were not a success.
This year he tried again with his new light airplane, an Ercoupe. At first he wanted to use frozen Lake Mendota, near Madison, for his circular runway, but the city council said no. Last fortnight he set up his apparatus on the ice of Lake Kegonsa, a safe distance from Madison. The spindle and hub were attached to a steel barrel frozen into the ice and guyed solidly. A double strand of woven nylon, 400 ft. long, led to a quick-release fixture under a wing of the airplane.
The first four tries were failures. The airplane swept part way round the circle and left the ground, but the rope always broke before the professor could make a controlled release. The fifth try was successful. This week the professor was doing it every time, slinging himself into the air and flying off with composure.
Professor Winans hopes to get permission to take passengers up on circular takeoffs, which he considers the utmost in safety, but his ultimate objective is to land in the circular manner. He has not tried it yet.
— America: Circular take off. Dr. J. Gibson Winans a university of Wisconsin physics professor, demonstrates a pinwheel take off. - British Pathé
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Not very off topic? A plane on a tether is very much a kite
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Airplanes take off and land best, and safest, into the wind.
https://www.reddit.com/r/Futurology/comments/1brjntw/a_startup_is_trying_to_tow_aircraft_to_cut_air/
As a glider pilot I can tell you, being on tow in bad weather is horrible. I am frequently at the limits of my controls just hoping the turbulence passes before I get to the outer limits of the tow box. If I go past a certain position behind the tow aircraft I am forced to release the tow rope or else I’ll be in “lockout”, only recoverable if the rope is released, or breaks. Weak-links are often installed in the rope system to prevent this. If the rope doesn’t break, the glider does, or the tow aircraft is pulled into a stall/spin.
Point is, towing in bad weather is very dangerous. Towing multiple gliders is possible but amplifies the instability of the system by mush more than 2X.
Here is an example of a tow pilot saving the day: https://www.youtube.com/watch?v=0wnnELRlopw Skip to about 5:50
The only way this could work is if the tow plane climbs steeply and quickly, then the cargo glider releases and flies the few hundred miles to the destination. Better if you can tow multiple gliders and they can each glide off to their destination. Otherwise it makes no sense.
In motorgliders we can do something similar. To maximize our range, we fly a “sawtooth” pattern. Meaning, we climb steeply with the motor on for 10 min or so, then shut off the motor and glide until we are back to our starting altitude. This is more efficient than just motoring straight ahead.
One problem with this might be weather. There would be quite a few days where this wouldn’t be safe, and people hate waiting for their stuff.
If we switch to an economy that emphasizes efficiency over timeliness, then maybe, but the low hanging fruit in this new economy would be sailing, not sailplanes.
Damon VanDer Lind and Andrew Goessling (X Makani) have a new venture
Magpie Aviation
They’re coordinating step towing battery electric aircraft as a range extending method
The tow line drogue steerer sounds a bit like a smart kite device
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Mozaero seems to want to do something related as well, very early stage though: https://www.mozaero.com/copy-of-technology
Sustainable Aviation
The aviation industry is responsible for 10% of global transport emissions, and faces increasing pressure to transition toward a zero-emissions future.
A large proportion of the energy onboard an aircraft is wasted carrying its own weight, and as much as 20-40% of that energy is used during takeoff and landing alone.
By combining efficient aircraft design with tethered propulsion technology, we can fly more sustainably and drive costs to new lows.
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