10 ms·

New aircraft rises 'like a balloon'

112 points by jdmark 8y ago

larrydag 8y ago
I'm curious if it can achieve the 20km altitude. I would bet weather would be a significant factor with keeping it aloft and on course.
foxyv 8y ago
I remember a proposal for one of these balloon gliders by NASA. Except on an entirely different scale. Be cool to see how it works out.
neom 8y ago
For those curious, University of the Highlands and Islands is in Inverness, Scotland. Quite a bit north of Edinburgh and Glasgow.
- deleted 8y ago
  [deleted]
- ZeroGravitas 8y ago
  That's the main campus but part of the concept is for it to be distributed over most of the Northern part of the country, including, as the name suggests, the islands: https://www.uhi.ac.uk/en/#campuses https://www.uhi.ac.uk/en/#campuses
  - therein 8y ago
    Just out of curiosity, do you have any relation to the Remarkable Tablet?
    - ZeroGravitas 8y ago
      Nope, no connection, both independently named after the character in the Iain Banks sci-fi novel, I assume.
hirundo 8y ago
With the soaring price of helium, I wonder what it costs to fill up that gas bag and how quickly it leaks out. And at what point filling it up costs more than the "almost expendable" aircraft. In the novel/film Contact the character S.R. Hadden lives in an airliner that rarely lands. With a larger Phoenix that lifestyle could become available to somewhat less wealthy billionaires. Maybe it could eventually become an atmospheric variation of seasteading.
- astazangasta 8y ago
  There are no really great lifting gases. Steam is ok but must be kept hot. H2 is dangerously explosive. Vacuum is the best (a so-called "null ship") but no known material can maintain the hull pressure under vacuum.
  - davnicwil 8y ago
    Excuse the silly question if it is one, but would one option be not a full vacuum but only marginally lower density of air inside the balloon, supplemented by solar-powered propellers? Could there be a material strong enough to handle a minimal density difference to provide enough lift for it to work?
    - nradov 8y ago
      No not even diamond is strong enough to allow generating a useful amount of lift that way.
    - lawlessone 8y ago
      To add to your Idea, could a "null ship" be carried to a greater height and then where the air is thinner have it's gas removed to take everything a little higher? Like rocket stages but for airships.
      - astazangasta 8y ago
        At a greater height you need a larger airship to provide the same lift. As you move towards the vacuum of space and the differential becomes less the lift per unit volume is less.
jpm_sd 8y ago
The same method of altitude control, using a compressor and an internal "ballonet", is used on Google Loon.
tim333 8y ago
The solar powered blimp in the photos looks too slow to stay in one place on a somewhat windy day, which would be necessary if it's a satellite replacement.
mothsonasloth 8y ago
University of the Highlands and Islands is considered a bit of a second rate institution in Scotland. A nice bit of publicity for them none the less. Hopefully they can develop this more and more. Scotland needs a boost to Aerospace after we got another Space port last year https://en.wikipedia.org/wiki/Sutherland_spaceport https://en.wikipedia.org/wiki/Sutherland_spaceport
- deleted 8y ago
  [deleted]
sandworm101 8y ago
Most of the mentioned use cases involve high altitudes. Higher altitudes = higher winds. The air is smooth up there but it does move. For instance, the upper level winds above my head right now are pushing 130knots. This thing will have to do more than glide gently up and down if it wants to maintain station at 10km+, airliner altitude.
- kbenson 8y ago
  I was wondering about this too. Then again, I don't know the air density difference. 130 knots at half the density (not that I know if half density is a feasible figure) would impart something like half the force, I imagine. Then again, lower density affects the ability of craft that use density for lift to operate.
  - saulrh 8y ago
    > not that I know if half density is a feasible figure 1/15th - .08 kg/m^3 at 20km, 1.2 kg/m^3 at sea level. 20km is way the heck up there. And yes, it does make it difficult to build something buoyant enough, which is why the use case for this is something like a geostationary internet balloon rather than for transportation. https://www.engineeringtoolbox.com/standard-atmosphere-d_604.html https://www.engineeringtoolbox.com/standard-atmosphere-d_604...
  - sandworm101 8y ago
    Density doesn't matter. As the density decreases the force of the wind does decrease, but the propulsive ability of propellers/wings also decreases. So the net effect is that the engines have to work equally hard.
- ChuckMcM 8y ago
  Yup, that has been the Achille's heel of these types of vehicles. One work around is to have a bunch of vehicles and have them move to altitude, stay over the area of interest as long as possible and then change to a lower altitude without the winds to move back to the head of the line.
- TheLoneAdmin 8y ago
NikkiA 8y ago
What decides if it's an airship or not is not whether it has wings, but whether it's lighter than air. This thing is lighter than air, thus it is an airship. Yet more terrible writing by the BBC.
- andrelaszlo 8y ago
  I might be misunderstanding things but it sounds like the "breathing" (compressing atmospheric air) gives it variable density? I guess it makes it a sometimes-an-airship.
- kjhughes 8y ago
  "The central fuselage is filled with helium, which makes it buoyant so it can ascend like a balloon." "And inside that there's another bag with compressors on it that brings air from outside, compresses the air, which makes the aeroplane heavier and then it descends like a glider."
- MagicPropmaker 8y ago
  It's both heavier and lighter! There's a compressor that can bring air in from the outside and make it heavier than air, and then this air can be released making it lighter again. This is explained in the article. It really is something new.
  - PeterisP 8y ago
    Like a hot air balloon which becomes heavier than air or lighter than air by regulating temperature in order to ascend or descend? That's fancy tech as of year 1800.
    - PhasmaFelis 8y ago
      As long as we're nitpicking terminology, hot air balloons aren't airships either, they're aerostats. And they certainly don't use their variable bouyancy to propel themselves in directed flight. Saying this thing is just a hot air balloon is like saying an airplane is just a glider.
agumonkey 8y ago
I'd love a fleet of small lighter than air balloons for city coasting
sarbaz 8y ago
This is exactly how submarines work
- evgen 8y ago
  Submarines use a prop for forward motion and are almost never 'gliding' using their planes. The purpose of the wings on this craft are similar to the variable-buoancy underwater drones that are out there, when the craft is rising the wings are trimmed to cause forward motion and then when it is descending they are trimmed in the other direction to continue forward motion.

112 points by jdmark 8y ago

I'm curious if it can achieve the 20km altitude. I would bet weather would be a significant factor with keeping it aloft and on course.

foxyv 8y ago

I remember a proposal for one of these balloon gliders by NASA. Except on an entirely different scale. Be cool to see how it works out.

neom 8y ago

For those curious, University of the Highlands and Islands is in Inverness, Scotland. Quite a bit north of Edinburgh and Glasgow.

deleted 8y ago
[deleted]
ZeroGravitas 8y ago
That's the main campus but part of the concept is for it to be distributed over most of the Northern part of the country, including, as the name suggests, the islands: https://www.uhi.ac.uk/en/#campuses https://www.uhi.ac.uk/en/#campuses
- therein 8y ago
  Just out of curiosity, do you have any relation to the Remarkable Tablet?
  - ZeroGravitas 8y ago
    Nope, no connection, both independently named after the character in the Iain Banks sci-fi novel, I assume.

hirundo 8y ago

With the soaring price of helium, I wonder what it costs to fill up that gas bag and how quickly it leaks out. And at what point filling it up costs more than the "almost expendable" aircraft. In the novel/film Contact the character S.R. Hadden lives in an airliner that rarely lands. With a larger Phoenix that lifestyle could become available to somewhat less wealthy billionaires. Maybe it could eventually become an atmospheric variation of seasteading.

astazangasta 8y ago
There are no really great lifting gases. Steam is ok but must be kept hot. H2 is dangerously explosive. Vacuum is the best (a so-called "null ship") but no known material can maintain the hull pressure under vacuum.
- davnicwil 8y ago
  Excuse the silly question if it is one, but would one option be not a full vacuum but only marginally lower density of air inside the balloon, supplemented by solar-powered propellers? Could there be a material strong enough to handle a minimal density difference to provide enough lift for it to work?
  - nradov 8y ago
    No not even diamond is strong enough to allow generating a useful amount of lift that way.
  - lawlessone 8y ago
    To add to your Idea, could a "null ship" be carried to a greater height and then where the air is thinner have it's gas removed to take everything a little higher? Like rocket stages but for airships.
    - astazangasta 8y ago
      At a greater height you need a larger airship to provide the same lift. As you move towards the vacuum of space and the differential becomes less the lift per unit volume is less.

jpm_sd 8y ago

The same method of altitude control, using a compressor and an internal "ballonet", is used on Google Loon.

tim333 8y ago

The solar powered blimp in the photos looks too slow to stay in one place on a somewhat windy day, which would be necessary if it's a satellite replacement.

mothsonasloth 8y ago

University of the Highlands and Islands is considered a bit of a second rate institution in Scotland. A nice bit of publicity for them none the less. Hopefully they can develop this more and more. Scotland needs a boost to Aerospace after we got another Space port last year https://en.wikipedia.org/wiki/Sutherland_spaceport https://en.wikipedia.org/wiki/Sutherland_spaceport

deleted 8y ago
[deleted]

sandworm101 8y ago

Most of the mentioned use cases involve high altitudes. Higher altitudes = higher winds. The air is smooth up there but it does move. For instance, the upper level winds above my head right now are pushing 130knots. This thing will have to do more than glide gently up and down if it wants to maintain station at 10km+, airliner altitude.

kbenson 8y ago
I was wondering about this too. Then again, I don't know the air density difference. 130 knots at half the density (not that I know if half density is a feasible figure) would impart something like half the force, I imagine. Then again, lower density affects the ability of craft that use density for lift to operate.
- saulrh 8y ago
  > not that I know if half density is a feasible figure 1/15th - .08 kg/m^3 at 20km, 1.2 kg/m^3 at sea level. 20km is way the heck up there. And yes, it does make it difficult to build something buoyant enough, which is why the use case for this is something like a geostationary internet balloon rather than for transportation. https://www.engineeringtoolbox.com/standard-atmosphere-d_604.html https://www.engineeringtoolbox.com/standard-atmosphere-d_604...
- sandworm101 8y ago
  Density doesn't matter. As the density decreases the force of the wind does decrease, but the propulsive ability of propellers/wings also decreases. So the net effect is that the engines have to work equally hard.
ChuckMcM 8y ago
Yup, that has been the Achille's heel of these types of vehicles. One work around is to have a bunch of vehicles and have them move to altitude, stay over the area of interest as long as possible and then change to a lower altitude without the winds to move back to the head of the line.
TheLoneAdmin 8y ago

NikkiA 8y ago

What decides if it's an airship or not is not whether it has wings, but whether it's lighter than air. This thing is lighter than air, thus it is an airship. Yet more terrible writing by the BBC.

andrelaszlo 8y ago
I might be misunderstanding things but it sounds like the "breathing" (compressing atmospheric air) gives it variable density? I guess it makes it a sometimes-an-airship.
kjhughes 8y ago
"The central fuselage is filled with helium, which makes it buoyant so it can ascend like a balloon." "And inside that there's another bag with compressors on it that brings air from outside, compresses the air, which makes the aeroplane heavier and then it descends like a glider."
MagicPropmaker 8y ago
It's both heavier and lighter! There's a compressor that can bring air in from the outside and make it heavier than air, and then this air can be released making it lighter again. This is explained in the article. It really is something new.
- PeterisP 8y ago
  Like a hot air balloon which becomes heavier than air or lighter than air by regulating temperature in order to ascend or descend? That's fancy tech as of year 1800.
  - PhasmaFelis 8y ago
    As long as we're nitpicking terminology, hot air balloons aren't airships either, they're aerostats. And they certainly don't use their variable bouyancy to propel themselves in directed flight. Saying this thing is just a hot air balloon is like saying an airplane is just a glider.

agumonkey 8y ago

I'd love a fleet of small lighter than air balloons for city coasting

sarbaz 8y ago

This is exactly how submarines work

evgen 8y ago
Submarines use a prop for forward motion and are almost never 'gliding' using their planes. The purpose of the wings on this craft are similar to the variable-buoancy underwater drones that are out there, when the craft is rising the wings are trimmed to cause forward motion and then when it is descending they are trimmed in the other direction to continue forward motion.