For Questions That Don't Merit Their Own Thread

[steve9728]

48 minutes ago, magnemoe said:

I have seen images of stuff like that used in quarries. including something who looked like an giant chain saw who cut rock and using long wires  you move to cut rock. 
Bu that is because you want stones of an regular size for building or decorations. For making holes explosives or an jackhammer on an excavator to break up stone. 
Here they are not taking out stone blocks but as its close to other buildings you can not do large blasts and the jackhammers are slow. 

But the reason why you dig down into rock is usually to get basements levels and that looks a lot like an parking garage. 
 

I agree with that. And I think those stone probably can sell for a good price hahaha

The one more thing I found that is cool is the dump trucks have all been replaced with purely electric vehicles. Otherwise, I guess the noise should be a bit more louder.

[kerbiloid]

6 hours ago, steve9728 said:

And what they are planning is going to build three 44 to 46-storey flats

Spoiler

_{If use the suggested 150 kt underground nuclear demolition system, it's a bad idea, as in future the gases from below will accumulate inside and any dosimeter will get mad.}

_{Better build a pool or so.}

 

[Exploro]

On 9/7/2022 at 12:44 PM, JoeSchmuckatelli said:

What is "Io's Footprint"? 

From what I read, the Io's Footprint is the aurora-like interaction between the Jovian atmosphere and the Io Flux Tube, a structure that magnetically links Jupiter to Io.

Edited September 20, 2022 by Exploro

[Autochrome]

So I've  been learning about Alkali metals in Chemistry class, and how they are extremely reactive with water.  The reactivity and explosions when coming into contact with water gets bigger as the mass and atomic number increases, until you reach Francium. Unfortunately (or probably fortunately) you can't put it in water because there are no stable isotopes that last more than 22 minutes, which brings me to my question.

What would happen if you could put Francium in water? What size of reaction and explosion would it have when it touched the liquid?

[Entropian]

41 minutes ago, Autochrome said:

What would happen if you could put Francium in water?

Radioactive hell, that's what.

[kerbiloid]

https://ru-m-wikipedia-org.translate.goog/wiki/Франций?_x_tr_sl=ru&_x_tr_tl=en&_x_tr_hl=ru&_x_tr_pto=wapp

Quote

Physical and chemical properties

The complete electronic configuration of the France atom is: 1s ² 2s ² 2p ⁶ 3s ² 3p ⁶ 4s ² 3d ¹⁰ 4p ⁶ 5s ² 4d ¹⁰ 5p ⁶ 6s ² 4f ¹⁴ 5d ¹⁰ 6p ⁶ 7s ¹ .

Francium is similar in properties to cesium . Always co-crystallizes with its compounds ^[6] . Almost all francium compounds are soluble in water. The relativistic effects of the 6p shell make the bond of francium with oxygen in superoxides, for example, of the composition FrO ₂ , more covalent than in the superoxides of other alkali metals ^[7] .

Since researchers have at their disposal only the smallest samples containing no more than 10 ⁻⁷ g of francium, information about its physical properties can only be determined by calculation, based on data for stable alkali metals. According to such calculations, the density of francium at room temperature is 1.87 g/cm³ , the melting point is 27°C, the boiling point is 677°C, and the specific heat of fusion is 9.385 kJ/kg ^[4] .

The ionization potential of the francium-212 atom from the ground state was experimentally measured ^[3] with high accuracy at the mass separator of radioactive nuclei ISOLDE at CERN , where this isotope is produced by irradiating a uranium carbide target with protons with an intensity of up to 10 ¹⁰ atoms per second (beam current 2 picoamps). In terms of reciprocal wavelength, the ionization potential is 32848.872(9) cm ^−1 [3] , which corresponds to 4.0727409(11) eV/atom , or 392.95976(11) kJ/mol .

Francium has the lowest electronegativity of any element currently known. Accordingly, francium is also the most reactive alkali metal.

It reacts violently with water, forming the strongest alkali  , francium hydroxide FrOH. Hydride FrH and francium oxide Fr ₂ O behave like similar cesium compounds, that is, they react violently with water, forming a hydroxide.

Chloride , nitrate , sulfate , fluoride , sulfide , hydroxide , carbonate , acetate and francium oxalate are highly soluble in water ^[1] . Poorly soluble perchlorate , picrate , iodate , chloroplatinate , chlorobismuthate , chloroantimonate , chlorostannate , francium nitrocobaltate ^[1] . Francium is extracted with nitrobenzene in the presence of sodium tetraphenylborate .Co -precipitates with simple and double cesium salts and with salts of heteropoly acids (silicontungstic, phosphotungstic, etc.) ^[1] .

 

it's a FrOH.

[SunlitZelkova]

Is it known what Musk’s ICBM based Mars architecture was supposed to look like?

Or was this merely an idea in his head that never got beyond the words “use retired ICBMs to get to Mars” before he found out he couldn’t buy them and decided to do SpaceX?

[DDE]

8 minutes ago, SunlitZelkova said:

Is it known what Musk’s ICBM based Mars architecture was supposed to look like?

Or was this merely an idea in his head that never got beyond the words “use retired ICBMs to get to Mars” before he found out he couldn’t buy them and decided to do SpaceX?

A better question is whether there even was a Mars in his plans at the time.

[StrandedonEarth]

36 minutes ago, SunlitZelkova said:

Is it known what Musk’s ICBM based Mars architecture was supposed to look like?

Or was this merely an idea in his head that never got beyond the words “use retired ICBMs to get to Mars” before he found out he couldn’t buy them and decided to do SpaceX?

I believe the plan was to land little greenhouses to experiment with growing things on Mars. Humans on Mars were not part of that plan. 

I think it was discussed in the book about the history of SpaceX, “Liftoff…” by Eric Berger, but I could be wrong about that. 

[kerbiloid]

Once he suggested a nuka-strike to warm the Mars.

This was the most viable of the SpaceX Martian suggestions.

[Starwaster]

38 minutes ago, SunlitZelkova said:

Is it known what Musk’s ICBM based Mars architecture was supposed to look like?

Or was this merely an idea in his head that never got beyond the words “use retired ICBMs to get to Mars” before he found out he couldn’t buy them and decided to do SpaceX?

It was probably just a stunt to send something to mars for publicity.  It was a bad idea that wasn’t actually planned out. The ICBMs in question were Russian and by their very nature are strictly sub-orbital. So we’re talking hypothetically about a small payload that would have then had to get orbital AND do a TMI to Mars.  Or some kind of direct launch to mars. 
 

I don’t have my PC available, just my phone so I can’t spreadsheet anything but I just can’t see anything but a small lander with a transmitter saying ‘I am here’

[DDE]

2 minutes ago, Starwaster said:

It was probably just a stunt to send something to mars for publicity.  It was a bad idea that wasn’t actually planned out. The ICBMs in question were Russian and by their very nature are strictly sub-orbital. So we’re talking hypothetically about a small payload that would have then had to get orbital AND do a TMI to Mars.  Or some kind of direct launch to mars. 

Dniepr is stated to be capable of 550 kg to TLI. That's surprisingly much.

[Starwaster]

1 hour ago, DDE said:

Dniepr is stated to be capable of 550 kg to TLI. That's surprisingly much.

Yeah I suppose I shouldn’t say things like that before taking into account that it could get a lighter payload into orbit. 

Edited September 22, 2022 by Starwaster

[DDE]

Is it possible to resurrect the tail gun as a CIWS?

I think I've asked the question a few years prior, and I'm still inclined towards "no", at least not in the form of a "hardkill" turret. However, I can't completely shut the door on the possibility.

I know that for air defense applications a quadruple or Gatling 30 mm is believed to be barely sufficient. But in case with aircraft, from the rear aspect the closing speed is a lot lower, and the target, while smaller, is a lot more fragile than an armored anti-ship missile. So, theoretically, some sort of a proximity-fused round could be effective; doesn't even have to be a rapid-fire high-velocity gun.

Thoughts?

[kerbiloid]

2 hours ago, DDE said:

Is it possible to resurrect the tail gun as a CIWS?

But they tend to sit together with others in the front cabin, since late Tu-22, late 3M, late B-52.

Why put them alone again?

***

And let them throw grenades again.

https://ru-m-wikipedia-org.translate.goog/wiki/АГ-2_(граната)?_x_tr_sl=ru&_x_tr_tl=en&_x_tr_hl=ru&_x_tr_pto=wapp

[DDE]

57 minutes ago, kerbiloid said:

And let them throw grenades again.

https://ru-m-wikipedia-org.translate.goog/wiki/АГ-2_(граната)?_x_tr_sl=ru&_x_tr_tl=en&_x_tr_hl=ru&_x_tr_pto=wapp

Oh, I was thinking of that little gizmo as well. Although it was more of a short-lived mine, IMHO.

[JoeSchmuckatelli]

5 hours ago, DDE said:

Is it possible to resurrect the tail gun as a CIWS?

I think I've asked the question a few years prior, and I'm still inclined towards "no", at least not in the form of a "hardkill" turret. However, I can't completely shut the door on the possibility.

I know that for air defense applications a quadruple or Gatling 30 mm is believed to be barely sufficient. But in case with aircraft, from the rear aspect the closing speed is a lot lower, and the target, while smaller, is a lot more fragile than an armored anti-ship missile. So, theoretically, some sort of a proximity-fused round could be effective; doesn't even have to be a rapid-fire high-velocity gun.

Thoughts?

What is the target of the CIWS / AD? 

(These are two different things, btw.  CIWS is generally an offensive capability.  AD, obviously, isn't...  ...  ... Um. Primarily. ) 

The image shown is an old-school bomber from the days when the bomber's threat came via bullets delivered by an aircraft that could see it.  Visually.  Up close and personal-like.  So - given that those days are pretty much gone - you would be looking for a defensive anti-missile solution using an updated, automated rear turret... And the answer is 'maybe' and 'at what cost/tradeoff?'. 

Figure that you would need not only the gun(s) and ammunition, but also the turret mechanism, framing and sensor arrays... And you've got a massive redesign & shift of weight. Good engineering can solve this - so it again goes to the threat: will the bomber have a sufficient threat of 'up the tailpipe missiles' coming at it to justify the effort and expense? (Tail defense turret may be utilized for incoming rear and maybe side threats - at the cost of constant 'here I am' pinging with the sole hope of overwhelming electronically/kinetically. )  If you think about it - in the days of the tailgunner - military planning was to just 'throw Hit Points at the problem'.  Lots of planes, tough planes, flying together, and maybe some make it to the target. In gaming parlance, the the Fighters would kite and the bombers, tank.  Warfare, at least from the Western perspective is different these days. 

The CIWS idea is interesting - but also, already implemented... Except in the form of the weapons officer.  The pilot's got control over the nose of the aircraft and modern missiles don't really need to be pointed in much more than the general direction of the target to go after it - its more of a conservation of energy thing than anything... So in multi person warcraft - the WO gets the independent targeting pods and associated weapons.  Adding a new thing at the back of the plane for the pilot to play with isn't going to improve his /her SA & effectiveness... And if everything was done right up front - the tail gun is looking back on smoking wreckage. 

Where the addition of such a turret/capability comes in, then, isn't in F/A or traditional (modern) bombers - but in the lingering attack craft like the AC-130... and I think it's efficacy and limitations have been demonstrated. 

 

Edited September 23, 2022 by JoeSchmuckatelli

[JoeSchmuckatelli]

FWIW - there are a host of videos, most from people with 'Eastern' accented English (or using AI) that do speculation Sim-runs on 'How Could Russia /China Defeat an American Carrier?' or 'Could a US Navy Black Sea Fleet Take Rostov on Don?' and they all feature waves of planes going down via swarms of missiles. 

For the state of modern warfare to get to the point where tail-gun-needed bombers are used for anything but the AC-130 style (absolute Air Dominance) role... Most nations' current arsenals would be expended, they would be in the full wartime economy and just-shy-of-nuclear war stance where everything but the kitchen sink is being thrown at the enemy. 

[kerbiloid]

1 hour ago, JoeSchmuckatelli said:

you would need not only the gun(s) and ammunition, but also the turret mechanism, framing and sensor arrays...

It's Tu-95, and the tail turret is still there.

All cannon turrets were remotely controlled since Tu-4 (unlicensed copy of B-29), unlike the B-29 tricky machine-guns. Because no air at 10+ km.

1 hour ago, JoeSchmuckatelli said:

And you've got a massive redesign & shift of weight.

Just 0.5 t for top and belly turrets (to the date are removed) and 1 t for the tail turret (was never removed except on Tu-95K).

[JoeSchmuckatelli]

1 hour ago, kerbiloid said:

It's Tu-95, and the tail turret is still there.

All cannon turrets were remotely controlled since Tu-4 (unlicensed copy of B-29), unlike the B-29 tricky machine-guns. Because no air at 10+ km.

Just 0.5 t for top and belly turrets (to the date are removed) and 1 t for the tail turret (was never removed except on Tu-95K).

I'm not actually describing continued use of legacy equipment with existing tail turrets.  Certainly, nations retain old gear - and they generally retain some military utility, even if not top tier effective.  (T-54 is still a tank... Effective vs trucks and APCs, etc.) 

But I read the question as 'can we use the concept of the tail turret and make it efficient /effective in the modern environment' - to which I'd answer 'no'. 

The only 'target' of such a defensive system would be AA missiles, whether SAM or A2A.  Highly unlikely to be engaged with guns by a fighter these days...  ...unless it's being used in some very backwater place.  And by then you will have eliminated anything the enemy could fly - so it's a redundant upgrade. 

My 'thought experiment' version of this was a tungsten-BB auto chaff shotgun that could be used to hard kill incoming missiles - but a pilot friend told me that you'd be losing more than you gain trying to build that into a jet 

 

[JoeSchmuckatelli]

Odd question (perfect place for these!) about the COM of off-shaped things:

If you were to release a bowling pin (or a hand-axe, or anything really heavy on one side vs the other) in space adjacent to a free-falling ship... would it change its orientation relative to the observer?

• i.e. you release it as stably as possible, imparting no other spin or residual motion... would the initial orientation change?
  • if it would move; would it settle heavy-end toward the Earth or in the direction of fall/motion?
  • if it would not move/reorient... is that because of a lack of drag?

This question arose b/c of @sevenperforce's comments on Shuttlecock behavior of a rocket during reentry.  I understand how atmospheric drag works - I'm just trying to figure out what would happen with a tail-heavy rocket in freefall, in vacuum... whether it would sling the butt around (eventually) and 'fall' or travel heavy end forward in the absence of drag.

[kerbiloid]

Why should it move relatively to ship?

It will be reoriented by tidal forces.

[JoeSchmuckatelli]

29 minutes ago, kerbiloid said:

Why should it move relatively to ship?

It will be reoriented by tidal forces.

I get that... but...  Remember: I'm the resident neanderthal.  What does that look like?

[SunlitZelkova]

2 hours ago, JoeSchmuckatelli said:

The only 'target' of such a defensive system would be AA missiles, whether SAM or A2A.

I think this was what he meant, not using it against aircraft.

On a separate note, assuming a large portion of a nation’s air defences are knocked out by ICBMs and SLBMs, the small number of surviving fighters resorting to guns isn’t too far fetched.

11 hours ago, DDE said:

Is it possible to resurrect the tail gun as a CIWS?

I think I've asked the question a few years prior, and I'm still inclined towards "no", at least not in the form of a "hardkill" turret. However, I can't completely shut the door on the possibility.

I know that for air defense applications a quadruple or Gatling 30 mm is believed to be barely sufficient. But in case with aircraft, from the rear aspect the closing speed is a lot lower, and the target, while smaller, is a lot more fragile than an armored anti-ship missile. So, theoretically, some sort of a proximity-fused round could be effective; doesn't even have to be a rapid-fire high-velocity gun.

Thoughts?

Reading anecdotes from B-52 gunners, it seems like the existing detection arcs on their fire control radars (and presumably the Tu-95’s too) make an acquisition impossible against SAMs, and thus a missile fired from below by a fighter would not be trackable either.

Even if the radar was extensively redesigned to cover a wider arc all around, the existing gun mounts would require another redesign to have more depression, another factor mentioned by B-52 gunners is that the tail gun wouldn’t depress low enough to target a SAM.

Of course another option would be to reinstate belly and dorsal guns, which the Tu-95MS does not have and the B-52 never had. But then there would be another two CIWS mounts, with radars and all, with their weight.

If the aircraft is flying at low altitude, the radars may have a hard time picking up the small AAMs. If the aircraft fly high, they will probably get salvoed by the long range SAM that is targeting it, which a single CIWS alone might not be able to handle. I’m not sure what fighters would carry in an air defence role, but if they have their max load out of some 6x or so AAMs they could launch a large salvo too.

I would say no. 3x heavy CIWS mounts and a new constraint on the flight profile does not seem like a lot, when more ECM equipment and stand off cruise missiles could be fitted instead.

I think only deep penetration missions (like trying to strike in a continental sized nation’s territory in a nuclear war) would require such a system anyways. The sorts of missions flown by bombers under normal circumstances (launching conventional ALCMs) would be flown within friendly airspace.

It would not be worth it for a nuclear war scenario when ECM equipment and more room for ALCMs would be more useful in conventional scenarios. I have seen opinions that bombers aren’t even a key part of nuclear war strategy nowadays anyways, and exist for a pure psychological deterrence purposes (although of course they still have their aforementioned conventional role).

[kerbiloid]

12 minutes ago, JoeSchmuckatelli said:

I get that... but...  Remember: I'm the resident neanderthal.  What does that look like?

Like a slowing pendulum.