4 ms·

So if I understand correctly you'd like to shoot planes into the sky with a giant railgun?

• baz00 3y ago
  I think getting the passengers to flap has a similar physics outcome.
  • hef19898 3y ago
    Sometimes passengers clap already, we are one letter away from harvesting that energy!
• standardUser 3y ago
  This is how they launch some jets on aircraft carriers. It sounds ridiculous to apply that to a passenger jet, but not really any more ridiculous than the fact that we routinely fly through the air for thousands of miles in the first place.
  • Kye 3y ago
    I'm no expert, but catapulting a sturdy ~30 ton fighter plane seems like a fundamentally different engineering challenge to catapulting a ~400 ton aluminum can.
    • standardUser 3y ago
      The E-2 Hawkeye is one of the largest plane that regularly uses catapult takeoff and it has a wingspan of 92' and weighs about 43,000 lbs. A220 and 737 both carry roughly 100-150 passengers and have wingspans of 115-120' and the lightest versions weigh around 130,000 lbs. Seems doable if the jet and catapult system were specifically designed for this purpose. Maybe less plausible for jumbo jets.
      • greedo 3y ago
        Catapults just shorten the runway needed. The plane still needs a ton of fuel to climb to altitude. Plus, I doubt you'd ever get a lot of civilians to fly off a catapult...
        • standardUser 3y ago
          The goal is to reduce the onboard fuel needed to achieve flight. I thought that was obvious from the parent comment. > Plus, I doubt you'd ever get a lot of civilians to fly off a catapult... I'm sure many short-sighted people said that about passenger air travel in general. Plus, if you actually watch a video of a modern catapult launch, you will see that it would be mostly invisible to passengers.
          • greedo 3y ago
            The amount of fuel needed to become airborne is a fraction of the amount of fuel needed to achieve cruising altitude. So using a catapult would only save a puny amount of fuel, as well as add risk to takeoffs. Plus, if you actually watch a video of a modern catapult launch, you'd realize that you're speaking out of your ass. Going from 0-170mph (the rotation speed of an A320), in a short amount of space is going to impart huge G forces on both the aircraft as well as the crew and passengers. Catapults also fail, and a "cold cat" on an airline sized plane (without zero/zero ejection seats for everyone) means a mass fatality event. Man, HN is just full of people suffering from Dunning-Kruger.
            • standardUser 3y ago
              I'm not sure why you think this needs to be exactly like an aircraft carrier, it does not. Why in the world would it need a shorter amount of space? An electric aircraft with heavy batteries could be brought up to speed with the same acceleration as current aircraft, and all of that energy used is weight not needed for the remainder of the ascent and flight. I have no idea how much energy could be saved, but it's not nothing. If that's not good enough for you, here's what fucking Airbus has to say: "In the report, Airbus explains that the initial power required for a passenger plane to take-off is only needed for a brief part of the total flight. This therefore poses an opportunity for a ground-based device to provide the propulsion needed and free the plane of its additional burden. With this in mind, the engineers at Airbus came up with an idea dubbed "eco-climb" which appears to draw inspiration from the catapult-assisted take-off system utilized on aircraft carriers." Dunning-Kruger indeed.
  • greedo 3y ago
    It sounds ridiculous because it is ridiculous.