Re: How can this be viable
> If an airship was used to transport troops to take on a militarily capable country, surely it just presents a nice large slow moving target for a missile system to put a few holes in?
Correct.
This is the primary reason they are no longer used.
This is an extract from Storm a biography of Irvin Crick. (The rain maker.)
In the early morning hours of April 4, 1933, Krick's habit of searching out fronts on weather maps involved him in an event which firmly set the course of his future.
With an early morning class at CalTech, Krick took a nap each night during the five hours of little flying activity when the IIO-miles-an-hour Fokker F-IOs flew from Salt Lake City to Las Vegas. As he turned in, he remarked to the radio operator, "I'm glad we're not flying off the coast of New Jersey tonight. There's a cold front coming down from the north-east and a warm front coming up from the south-west. When the two meet there is going to be one awful mix-up. It'll be very violent."
Krick was no sooner asleep than he was shaken awake by the radioman.
"My God, the Akron just went down in the Atlantic off Bamegat Light -right where you said all that rough weather was coming!" he exclaimed. The Akron was an enormous airship -78? feet long, large enough to accommodate five airplanes aboard. It was the pride of the United States Navy. Seventy-three men died in the disaster, the headline event of the day.
At school later in the morning Krick sought out Dr. Theodore von Karman. Known as "master of the wind" for his knowledge of fluid mechanics, this Hungarian-born scientist was chairman of CalTech's Guggenheim Aeronautics Laboratory, which later was to spawn the world-famous Jet Propulsion Laboratory. Von Karman also headed the Goodyear Airship Institute at Akron, Ohio.
"The Akron never had a chance," Krick said. "The wind shear set up by these two opposing air masses blowing in opposite directions was bound to destroy the ship. She should never have been flown into this kind of weather."
Von Karman was impressed by Krick's earnestness. "Get me the velocity of these winds and we'll calculate the stresses on the ship," von Karman told him.
The calculations, by Frank Wattendorf, Karman's assistant, proved Krick to be correct:
The Akron, broken in two like a stick across the knee of a giant, was doomed from the moment the ship left the hangar, although the United States Weather Bureau had reported that the storm posed no danger to flying that day.
***
So that is major problem #2 covered. Modern meteorology can help plan journeys of 5 days and get most aircraft out of harm's way any old three days ahead. I don't know what metal fatigue and electro-static problems still remain.
Problem 3 is the gas and containers
And a loooooong way behind is the ballast problem. There is always going to be a problem with trim, even the most modern submarines have the same thing to contend with. With aircraft yawing and etc., is part of the fun of flying and is compensated for by computers in larger craft.