Glad to hear Aeroscraft has gone into production. I've always thought that if I had the ear of someone feeling particularly philanthropic, it would an amazing project to buy one or more of these and convert them into fully functional trauma hospitals/mobile pathology labs for use in humanitarian disaster relief. A number of countries have ships in their navies that are set up for such work, but they often have difficulty getting to where they are needed, and many of the high-tech pieces of equipment you really want in such a location (CT scanners/flow cytometers etc) are bulky and tend not to be so robust when moved/vibrated around a lot on planes/ships etc.As far as space applications go, I imagine the bigger airships would be quite good at moving rockets to launch sites, and could make more viable some of the currently less accessible launch sites - which nonetheless would be useful for accessing a specific (low radiation) orbit like Equatorial LEO.
Yes I think they have tremendous potential. And it seems that there are now a few serious irons in the fire so to speak. So hopefully we will see an economically viable system emerge in the not too distant future. My hunch is that the Aeroscraft has the best chance simply because it lifts 66 tons with a generous size envelope. So long as the airfreighting of ungainly items can carry the costs of the Aeroscraft that is.So much has been promised over so many years can we see this concept finally succeed?Well flying wings were a rubbish idea for years, then they built the B2.RTLS rockets were a rubbish idea, then they built the Falcon 9.So I hope so!
Having nothing interesting to say, i'll say this is a cool thread and airships are awesome. That said, is there even a theoretical basis or relevant recent trade analysis for making hydrogen in airships usable and safe ?
Aside from uses on Earth, I'm excited to see this tech return because it augurs well for the possibility of an airship mission to Titan. Titan of course being the only moon in the solar system with a wonderfully thick atmosphere like the Earth's. It would require some unique tricks to get the airship to inflate only after Titan atmospheric entry, but the science pay-off would be tremendous. There has also been some mention of using this approach for Venus scientific missions.
IIRC it was never the hydrogen in the Hindenburg that was the problem, but every chemistry student who has ever had a good teacher has seen a hydrogen filled balloon combust with spectacular results, so if you'll forgive the pun, I'm pretty sure hydrogen airships will never get off the ground, helium shortage or no.
Finally, a question... If any of these variations work, and lead to a super high altitude airship capable of lifting useful payload masses, would it be conceivable for such an airship to achieve an altitude where an ion engine would provide sufficient thrust to slowly accelerate the airship to orbit?
Yes, I am quite aware for the need for velocity to actually achieve orbit, although there might be some benefits just to having an extremely high altitude platform for suborbital missions (telescopic obvservation platforms, for instance, that do not necessarily have to go in orbit, they just have to get above the majority of atmospheric interference for extended durations).
Once in an orbit, no matter how low, ion thrusters are sufficient to lift satellites into orbits as high as they have sufficient propellant for... It just takes a really long time. Now, there is no question of the airships crashîg to the ground, so long as the envelopes remain intact, so there would be plenty of time for an ion thruster to slowly accelerate the airship to sufficient velocities. However, I do not know offhand if such thrusters would be able to overcome even what little atmospheric drag exists at such high altitudes.
The benefit is that you would require much less propellant, the rocket would benefit from virtually full vacuum thrust and Isp, and the rocket stage would not have to fight against sognificant atmospheric drag. For reference, the Saturn V first stage only propelled the apollo spacecraft to an altitude of 36 miles. This is comparable to the 50km+ altitudes already achieved by some helium balloons.
Quote from: MIKKELH on 04/04/2016 07:29 pmOnce in an orbit, no matter how low, ion thrusters are sufficient to lift satellites into orbits as high as they have sufficient propellant for... It just takes a really long time. Now, there is no question of the airships crashîg to the ground, so long as the envelopes remain intact, so there would be plenty of time for an ion thruster to slowly accelerate the airship to sufficient velocities. However, I do not know offhand if such thrusters would be able to overcome even what little atmospheric drag exists at such high altitudes.Like mikelepage, I don't want to stomp, but...unfortunately, no. Pretty much by definition, an airship which depends on buoyancy to stay aloft will have too much aerodynamic drag to be accelerated to orbital velocities. Buoyancy depends on displacing air, displacing air requires volume, volume requires surface area.
Have you read the financials of that pitch? Yet still people seem to be throwing money at them like crazy.It's the same thing as it was with Cargolifter and with Zeppelin NT... The one thing these machines have always been really good at is combusting money like rocket engines burn fuel.
I personally think Aeroscraft has the best approach, but it's hard to argue that Lockheed has a bad approach after landing a dozen sales. What I like about the Aeroscraft approach is you can get the superior fuel economy of a more classical airship but still enjoy good ground handling while off-loading. The catch of course is the added weight of the frame and the helium compression system. That means a HAV or Lockheed airship is likely to be more capable at the same size.
Not a big market but could provide the sales to keep a small company like HAV alive, this is where I think Hybrid Air Vehicles has a huge advantage over the competition, the development costs have largely been absorbed by the US military, so I believe the vehicle will end up being the cheapest on the market and why the military aren't facing the cut backs they were, politicians still want to get value for money.