Hacker News Reader

Comment by jedberg | Hacker News Reader

Taking an airship would be like taking a cruise but in the sky.

Also one advantage airships have is that they can dock to pretty much any tall building. The Empire State Building has airship docking capability.

Imagine taking a transatlantic cruise on an airship that leaves from the top of the Empire State Building and docks at the top of the Eiffel Tower?

View on HN

I also used to 'sort of know that' and then I came across something on YT about the updraughts and air turbulence etc. Can't find the clip I saw but this link says pretty much the same.

"A popular myth claims that the top of the Empire State Building was meant to serve as a docking station for dirigibles, but the building's owners say that the story is just hot air."

https://www.youtube.com/watch?v=_wimlrgwhgg

Sibling comment has a page that says:

> Without doubt, the tallest mooring mast ever designed was the spire of the Empire State Building which was originally constructed to serve as a mooring mast, although soon after converted for use as a television and radio transmitter tower due to the discovered infeasibility of mooring an airship

Now I’m curious what it actually is.

They did build the Empire state building with a mooring mast and a a lounge / ticket area and a way for the passengers to get on the plane. But it was purely speculative, and though they took publicity photos, they never used it(remember: there were only a handful of commercial airships).

There used to be a commercial heliport on top of the Pan Am Building over Grand Central Station. The first helicopter crash that sent chunks of metal flying 600 feet down to streets with huge amounts of foot traffic permanently closed it. I'm sure something similar would have happened had the Empire State Building 'port' actually been used.

Unlike the Empire State Building airship dock, the Pan Am heliport was an actual and working mini 'airport' with regular scheduled flights / pick-ups-drop-offs for years.

This is also why none of the companies building powered lift eVTOL aircraft like Joby and Lillium are unlikely to achieve mass market success. Even if they can achieve FAA certification, there aren't enough places to land in dense urban areas.

> The Empire State Building has airship docking capability.

This photo shows a much less tall airship mooring mast.

https://rarehistoricalphotos.com/mooring-mast-1930s/

It doesn't look like that kind of mooring would be up to the modern safety standards, especially when you add high winds that are common at the top of skyscrapers.

The picture below has an airship getting flipped on its nose by a gust of wind while moored to a tower.

It seems to me that airships really need two mooring masts. One at the front and another at the back. Maybe the one at the back flips up to lock on once the one in front is secure?

Tbh, it'd probably be inherently safer. The ship should be easier to control because the air at the top of a skyscraper is likely to be less turbulent. And if there is an unexpected down draught, then there is a lot more leeway before the ship and its compliment get smashed into the ground.

Ground handling and docking is one of the main, and fairly frequently fatal, causes of airships accidents, see https://en.wikipedia.org/wiki/List_of_airship_accidents. Fwiw mitigating is definitely possible. But it requires specialised docking equipment to be available anywhere they are to set down. Which is why I suspect they'll make rather better Bazillionaire play things than humanitarian aid delivery mechanisms. They are very cool though.

That would be very risky: those monsters aren't friends with the wind. Any glitch and a lot of power gets applied to that building. Another glitch and a large frame falls down on the street.

You can read reports of Nobile airship trips. And wind could delay trips by days.

Apparently not too risky, since, as the parent pointed out, in the early part of the previous century, it wasn't unusual for tall buildings to be used for airship docking.

The Empire State Building mooring wasn't a one-off. There were many others. What is now the InterContinental Hotel in Chicago was one.

Thank you, I will look it up. I wonder what the success rate was for those, I thought they sometimes went to backup locations.

I read accounts of using airships in the exploration of the North in the early 20th century and I got the impression that they often dropped ropes in a clear spot away from the exact landing point and were led by a landing team to the final docking, which would be hard to do in the middle of a city today.

That's because human lives were cheaper back in those days. The problem with docking a giant people carrier above a densely populated area is that you have even more lives at stake.

We send airplanes over densely pack cities all the time. We even let the rather pointless Goodyear blimp do so. Docking an airship would be safer if the area beneath it was completely clear such as a river, but in normal wind conditions it isn’t particularly dangerous.

Goodyear blimp only flies in relatively good weather. On airplanes over cities though: compare the cross-section and the corresponding force exerted by the wind on a modern jet and a blimp. Jet engines can compensate for wind gusts that would make landing an airship in a tight spot hopeless.

A fun example: https://www.youtube.com/watch?v=ZPn3MBNt7Rc

Airline landings really aren’t very precise which is why runways are so wide.

In terms of wind, airships with the right control systems can be designed to hold position in 50+MPH guts. That takes a lot of power and rapid response, but modern airships can do 110kph and presumably commercial adoption would need higher speeds.

> In terms of wind, airships with the right control systems can be designed to hold position in 50+MPH gusts. That takes a lot of power and rapid response

I am not sure: countering the change in direction seems very hard. But I do wish luck to those who are working to push this technology along.

> modern airships can do 110kph

That is how fast the Zeppelins of 100 years ago traveled: cruising speed of 76 mph.

The response speed is via reversible variable pitch propellers, which is a very cool technology. https://en.wikipedia.org/wiki/Variable-pitch_propeller_(aero...

Any flying machine has some maneuverability when flying PASS a populated area, even in emergencies. If you just dock above the area at all time, it will increase the risk immensely.

You wait for hurricane, typhoon and/or cyclone for quick travel.

> like taking a cruise but in the sky

Minus the lift v. float economics. That would strike at some combination of affordability and availability of attractions.

Reply on news.ycombinator.com