Can a physicist help me understand something here? Assuming each of these can carry ~650lbs at 30mph. They're 60feet long and have a VERY lightweight airframe. How would these craft deal with wind? do they just get blown away every time there is a gust?
One clarification, the full-scale version's max speed is ~75 mph, and typical cruise speeds will be 50-60 mph. The 35 mph number in the article is our subscale prototype. We loose range in a headwind, but on most days the aircraft has more than enough range to complete our target missions. And on the days the weather's too bad to fly, many other small aircraft are grounded too.
- Joe from Buoyant
Wind is generally able to be forecast fairly well today. Applications sensitive to wind, especially to gusts, as light weight large side area vehicles will be, are going to be not usable when it's gusty. But that doesn't mean they're going to be not usable often enough to not be cost effective, and there may be options suitable to the specific mission to, for example, deliver a package simply nearby instead of at the destination.
There's also other design shapes, one of which I'm a little familiar with being Skylifter, that is saucer shaped. Their target audience is heavy lift, but they were very intent on minimizing wind effects and so chose that shape.
This specific shape though will be suitable a lot of the time for a lot of missions, and may even be more cost effective than a different shape - my non-CFD'd thought here is that the long skinny shape will likely get more lift from flow than a saucer. Maybe someone has done that research, as I'd love to read through it.
The top speed can be taken as simply relative to a constant wind speed. Say they have a max speed of 30mph heading against the wind at 25mph. The net will simply be 5mph aka super slow.
Gusty wind is more complex as it depends on cumulative drag factor. You can estimate their forward drag by knowledge about the motors they are using (energy -> drag work).
Likely, unless their motors are tiny, the even the forward drag is quite high. This is why their max speed is not something like 300km/h.
Wind will never not be a problem for airships. At best, modern weather radars and forecasting might allow airships to avoid storms better than their early 20th century counterparts did.
Incidentally, a lot of casual airship fans pin hopes on helium instead of hydrogen to keep airships safe. But the deadliest airship disaster in history was a helium airship, the USS Akron, which was destroyed by bad weather killing 73 of the 76 aboard.
> "might allow airships to avoid storms better than their early 20th century counterparts did"
Not sure they wanted to; from [1]: "To maintain altitude, Hindenburg would brush against clouds and collect rainwater in gutters that fed the ballast tanks. If we passed through a shower every few hours there was no need to release gas. There were occasions when no rain was available, but we were rarely far from a suitable shower."
>the deadliest airship disaster in history was a helium airship
I think that may be a misleading way to put it.
"Most casualties had been caused by drowning and hypothermia, since the crew had not been issued life jackets, and there had not been time to deploy the single life raft"
When a large airplane enters heavy turbulence, stalls and falls into the sea, I don't think that would be the usual scenario.
I don't think that is misleading; a storm downed the airship, resulting in nearly all the crew dying. That they didn't die on impact doesn't change things. If a torpedo sank a ship and most of the crew died from exposure in the water rather than the explosion (USS Indianapolis), you'd not say that torpedoes aren't a major threat to ships.
Another comment elsewhere in this discussion says that airships stalled for fear of another Hindenberg. 'Fear' suggests some measure of irrationality, as though the Hindenberg were a one-off accident. The reality is these things were crashing all the time. People had ample reason to rationally expect airships would continue to crash.
> "But the deadliest airship disaster in history was a helium airship, the USS Akron, which was destroyed by bad weather killing 73 of the 76 aboard."
Worse than that in fate's sense of irony, after the Hindenburg disaster the US authorities banned Hydrogen as a lifting gas and built the USS Shenandoah as a Helium airship. When a Hydrogen airship of that era flew too high it had valves at the top to vent Hydrogen to the atmosphere and reduce buoyancy, but Helium was 50x-100x more expensive and the Sheandoah had its valves sealed so the crew couldn't waste any of it. It hit a turbulent updraft, rose so high the gas pressure in the balloons was past spec, and this is suspected to have contributed to it breaking up and crashing, killing 14 people.
