Consider a helium airship with a mass of 20000 lbs, capable of lifting a payload of 4000 lbs. Replace the helium with an equal volume of hydrogen and the max payload goes up to just over 5900 lbs - a significant difference.
Thanks for the update Elendil’s Heir. These blimps are obviously not for carrying people, and will be more or less stationary. I had assumed that classified sensors on geosynchronous satellites could do something similar, but perhaps not. They may be just too far up.
Maybe the can, but they almost certainly can’t do it as cheaply. Satellites are pretty far up, especially geosynchronous ones, so you’d need better optics to see that far. Washington’s not on the equator, so they’d need a flock of satellites, only some of which could be on station at once (you can increase the duty cycle per satellite, but at the cost of putting them even higher at the important part of their orbit). Launching anything into space is horrendously expensive, far more expensive than launching a balloon. And just possibly relevant, the balloons will also be more easily visible from the ground, which the Army might regard as a valuable deterrent.
The US used/uses blimps in Iraq/Afghanistan/other operating areas. They were tethered and equiped with day/night vision sensors to protect operating bases.
Aside: I just clicked the link to those Army blimps, and it looks like they have an opening in their acronym-writing department. I mean, seriously, smushing five words into a single letter of the acronym, and they still can’t make it spell something meaningful, or even pronounceable?
After looking through the H v. He arguments, a question occurs to me: as far as containment, does hydrogen call for gas bags made of a denser material than would be needed for helium? Even a small difference in thickness or material weight could make a really big difference in the weight of a huge gas bag.
I do not know about the gas bags, but a survivor of the Hindenburg, a cabin boy if I am not mistaken, kicked through the side of the ship to jump out and escape.
As I recall, all the dirigibles of that era were basically a double-hull type design. The gas bags were big interior balloons, then there was a metal frame with fabric stretched over it, not that different from the contemporary aircraft, so being able to kick through it would had been pretty easy, especially in an adrenaline-fueled panic.
I can imagine we could build modern dirigibles out of CF, combining the gas containment and rigid structure into a unified package. Such a design would have lower drag, could be built with flexibly-connected, curved panels arranged so as to deform to shed cross-winds, would have a smaller crew because of electronics and would have the advantage of NOAA data for better flight planning. Realistically, a Hindenburg-size modern dirigible could probably ferry a couple hundred passengers across the continent or an ocean in relative comfort in only maybe twice the time of an airliner, using a bit less fuel. Probably not for a lower fare, though.
Depends. I don’t know about then, but of late (contemporary aircraft) fabric on airframes is unbelievably strong. I remember a Bellanca Viking sales trick was to stand back and toss a 1 pound steel ball at the side of fuselage fairly hard. It bounced off, never penetrating the fabric covering. I doubt they had similar materials back then though.
BTW, the Viking was a fabric fuselage & empennage with a wooden wing. And it still sold in an age of aluminum aircraft.
Sky Captain is an alternate NYC, and it’s the Hindenburg III. The TV show *Fringe *also had docking dirigibles on the ESB in its alternate universe.
Whatever it had is still there. In 1931 a Navy dirigible tried to dock on the mast and found the winds perilous up there. It’d be something else - even in excellent conditions - to have some kind of a gangplank for passengers to disembark from. Besides, the mast has the TV antennae which weren’t there in the 1930’s.