For Questions That Don't Merit Their Own Thread

[Terwin]

1 minute ago, DDE said:

Let’s revisit the old “shoot gas tank for car explosion” trope. Justs how impossible is it?

And what happens if we use an actual gas (propane)?

For gasoline to explode and not just burn, it needs to be mixed with sufficient oxygen.  Usually this is not the case when it is sloshing around in a liquid form.

If you shoot a full gas-tank with an incendiary round, you will probably have a tank with 2 holes and puddles of burning fuel forming on both sides.

At best if you had a tank that was almost empty of liquid fuel and had the right mixture of air and evaporated fuel, you could cause an explosion inside the tank, but I don't know enough chemistry to say how much of an explosion that would be and if that could even rupture the tank.

[Cunjo Carl]

3 hours ago, DDE said:

Let’s revisit the old “shoot gas tank for car explosion” trope. Justs how impossible is it?

And what happens if we use an actual gas (propane)?

Ooh, 'practical' general chemistry.

I was always taught that cars make for good concealment and reasonable cover in a shootout (better than nothing), and that the most common issue was actually a fuel line (not the gas tank) being hit and leading to rapid conflagration, but not technically an explosion. Fortunately, never had to put anything into practice!

Propane tanks are under positive pressure, 5-10 bar gauge (75-150psig) temperature pending. That's enough pressure to make an 'explosion' (a loud bang), and fling highly volatile liquid everywhere even if nothing ignites! Igniting liquid butane isn't particularly hard, and I have to figure propane is easier. Getting a proper explosion from the gas is quite a bit trickier though (thankfully!) . A little bit like spaceX, I like to differentiate 'static fire anomalies' from real explosions . It's fairly easy to get an idea of how easy something is to explode from checking its explosive limits (though not necessarily how well it burns). https://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html . Propane looks pretty standard for a flammable gas at 2-10%. Even though only the upper and lower explosive limits are shown, there's often non-explosive concentrations within the region. Anyways, bottom line is I'd expect lots of trouble occurring, but almost definitely not a proper explosion from a single round. Hmm, that is unless you used one of the few remaining Gyrojet bullets! I think I'd pay to see that experiment! (Edit: Joking, just to be clear)

I'd be surprised if someone hasn't tried a practical experiment of these and posted it to youtube. This seems like clear mythbusters territory to me, especially given their Hollywood origins.

Edited January 18, 2019 by Cunjo Carl

[kerbiloid]

They have
https://www.google.ru/search?q=shot+fuel+tank&newwindow=1&client=opera&hs=3jx&source=lnms&tbm=vid&sa=X&ved=0ahUKEwj0ouHki_jfAhXKWSwKHc8dBSMQ_AUIECgD&biw=1920&bih=980

[DDE]

5 hours ago, Cunjo Carl said:

Ooh, 'practical' general chemistry.

I was always taught that cars make for good concealment and reasonable cover in a shootout (better than nothing), and that the most common issue was actually a fuel line (not the gas tank) being hit and leading to rapid conflagration, but not technically an explosion. Fortunately, never had to put anything into practice!

Propane tanks are under positive pressure, 5-10 bar gauge (75-150psig) temperature pending. That's enough pressure to make an 'explosion' (a loud bang), and fling highly volatile liquid everywhere even if nothing ignites! Igniting liquid butane isn't particularly hard, and I have to figure propane is easier. Getting a proper explosion from the gas is quite a bit trickier though (thankfully!) . A little bit like spaceX, I like to differentiate 'static fire anomalies' from real explosions . It's fairly easy to get an idea of how easy something is to explode from checking its explosive limits (though not necessarily how well it burns). https://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html . Propane looks pretty standard for a flammable gas at 2-10%. Even though only the upper and lower explosive limits are shown, there's often non-explosive concentrations within the region. Anyways, bottom line is I'd expect lots of trouble occurring, but almost definitely not a proper explosion from a single round. Hmm, that is unless you used one of the few remaining Gyrojet bullets! I think I'd pay to see that experiment! (Edit: Joking, just to be clear)

I'd be surprised if someone hasn't tried a practical experiment of these and posted it to youtube. This seems like clear mythbusters territory to me, especially given their Hollywood origins.

Thing is, there are options beyond 9 mm most of these tests used.

As there are options beyond ordinary kinetic FMJs.

[Cunjo Carl]

1 hour ago, DDE said:

Thing is, there are options beyond 9 mm most of these tests used.

As there are options beyond ordinary kinetic FMJs.

Very true, I kinda took it on assumption your question was meant for a common handgun or .556, or similar. If you decide to move the firepower northwards, there's really no sensible limit to how massive people have made things that shoot so I'm sure there's something that'd make a bang! I think we'd have to figure a 12Ga slug followed by some of this stuff would make for fireworks.... Oh, to have a backyard that large. For the record, I'm saying this on assumption, I've never worked with it.

 

Spoiler

 

 

By the way, stay tuned until after the 3 minute mark to get a science lesson! I'm a fan of the channel to say the least.

[DDE]

6 hours ago, Cunjo Carl said:

Very true, I kinda took it on assumption your question was meant for a common handgun or .556, or similar. If you decide to move the firepower northwards, there's really no sensible limit to how massive people have made things that shoot so I'm sure there's something that'd make a bang!

You don’t need to go northwards by much. For example, the Soviets were so optimistic they made an API round for the 7.62 mm pistol cartridge used in the Tokarev pistol and various submachine guns, with the explicit purpose of gas tank explosions (again, perhaps optimistic). Hell, even the current 9x21 mm that’s being aggressively marketed this month has an AP-tracer variant.

Amd them you have the FSB reportedly embracing Wh40k cosplay with a 12.7x55 mm:

Edited January 19, 2019 by DDE

[ARS]

Does Focke-Wulf Triebflugel design considered airworthy? If it's plausible for such design to be considered airworthy, how's the performance when compared with conventional aircraft design? Especially on it's intended role as interceptor aircraft

The three rotor blades were mounted on a ring assembly supported by bearings, allowing free rotation around the fuselage. At the end of each was a ramjet. To start the rotors spinning, simple rockets would have been used. As the speed increased, the flow of air would have been sufficient for the ramjets to work and the rockets would expire. The pitch of the blades could be varied with the effect of changing the speed and the lift produced

Edited January 20, 2019 by ARS

[DDE]

52 minutes ago, ARS said:

Does Focke-Wulf Triebflugel design considered airworthy?

Not in context. The US had two similar VTOL projects five or so years later, using ordinary tractor turboprops to get similar expected rate of climb. Creating a way to land any of those three vehicles would have required a massive project to build a sophisticated landing control system; as-is, only the best test pilots could land it due to the awkward seat position.

Furthermore, on the tailless Pogo the US found grossly inadequate control authority. Combine that with the gyroscopic inertia of the massive rotary wing, and you’d probably be looking at an unsteerable aircraft.

Finally, the peroxide for the Walter monoprops was scarce at the time of its construction, between the torpedoes, the V2s, the Walter U-boat project and the Me-163. BMW’s nitric acid engines would have helped, but they were only ever found on experimental Me-262s.

[kerbiloid]

Spoiler

Hey! My first rockets in KSP were flying like that!

Until I discovered "T" button.

 

[Xd the great]

How do payload adaptors work?

[p1t1o]

On 1/18/2019 at 2:33 PM, Terwin said:

For gasoline to explode and not just burn, it needs to be mixed with sufficient oxygen.  Usually this is not the case when it is sloshing around in a liquid form.

If you shoot a full gas-tank with an incendiary round, you will probably have a tank with 2 holes and puddles of burning fuel forming on both sides.

At best if you had a tank that was almost empty of liquid fuel and had the right mixture of air and evaporated fuel, you could cause an explosion inside the tank, but I don't know enough chemistry to say how much of an explosion that would be and if that could even rupture the tank.

It can be a real risk, probably more so in larger fuel tanks. There are various systems, suppressant foams, nitrogen inerting, self sealing tanks etc. in existence that are used to reduce the risk.

http://news.bbc.co.uk/1/hi/uk/7683909.stm

I would wager cars and car-sized fuel tanks are less vulnerable due to rarely being fired upon with high-calibre weapons and lower internal volume means a small fire - if anything - is far more likely than a large conflagration or explosion.

 

[DAL59]

What does the UI for the LHC look like?  

[Green Baron]

If you mean the Large Hadron Collider, i do not expect "it" to be controlled by a single piece of application software. It consists of several accelerators, the huge ring, cooling, power supply, several "rooms" or better edifices, below and above ground, for (changing) experiments and equipment of all sorts, it is a huge complex, and a worldwide network of computers are connected for all sorts of .. well computations.

Anyway, saying "several flavours of the Linux command line" is surely not totally incorrect ;-)

Edited January 21, 2019 by Green Baron

[DDE]

3 hours ago, Green Baron said:

If you mean the Large Hadron Collider, i do not expect "it" to be controlled by a single piece of application software. It consists of several accelerators, the huge ring, cooling, power supply, several "rooms" or better edifices, below and above ground, for (changing) experiments and equipment of all sorts, it is a huge complex, and a worldwide network of computers are connected for all sorts of .. well computations.

Anyway, saying "several flavours of the Linux command line" is surely not totally incorrect ;-) 

Spoiler

Yep, a Linux Astra Smolensk.

Oh, wait, we're not supposed to share pictures of our workplace...

*BLAM*

http://linux.web.cern.ch/linux/nextversion.shtml, natch.

[kerbiloid]

Spoiler

The callcenter is nice, but the coworking looks cramped.

 

[tater]

 

[magnemoe]

On 1/19/2019 at 2:04 AM, Cunjo Carl said:

Very true, I kinda took it on assumption your question was meant for a common handgun or .556, or similar. If you decide to move the firepower northwards, there's really no sensible limit to how massive people have made things that shoot so I'm sure there's something that'd make a bang! I think we'd have to figure a 12Ga slug followed by some of this stuff would make for fireworks.... Oh, to have a backyard that large. For the record, I'm saying this on assumption, I've never worked with it.

 

  Reveal hidden contents

 

 

By the way, stay tuned until after the 3 minute mark to get a science lesson! I'm a fan of the channel to say the least.

after 12.7 something we moves into cannons, if you hit something with an above 3 cm shell and get an good secondary explosion it was an hostile target, at that firepower fuel tanks becomes secondary effects. 
Yes its nice if hitting massed trucks with staffing or cluster bur an secondary effect causing fire while firefighters are hiding because of the attack. 
In short heavy military weapons are so powerful its not important. 

Back to everyday life, it was an explosion in Mexico killing 66 people tapping into an gasoline pipeline. 
Here you probably got an fire boiling gasoline and creating an explosion. If you have an fire below an gasoline tank. it will boil the gasoline in the tank probably giving you an explosion down the line. 

[Cunjo Carl]

@magnemoe

I think I'm missing context, but any loss of life is terrible, and 66 is tragic. If you were affected by the event, I'm very sorry for your loss.

[XB-70A]

3 hours ago, magnemoe said:

after 12.7 something we moves into cannons

I would be interested to know if they finally found a deal about the caliber deciding between. About cannons, it could seems like it's starting at 15 mm (this pretty unusual caliber having been developed for the MG 151... before being replaced by its 2 cm variant) as some systems, such as the Soviet KPV (14.5 mm), or the German MG 131 (1.3 cm) were designated as "heavy machine guns". Still, there are some "exceptions" around, such as the ".950" JDJ cartridge (which is equivalent to 20x110 mm), but the few firearms able to accept it are still designated as "rifles".

[DDE]

7 hours ago, XB-70A said:

I would be interested to know if they finally found a deal about the caliber deciding between.

Not really. This thing, made from rejected 23 mm AA gun barrels, mucked things up again.

N.B. Russian firearm regs discount the existence of rifled shotguns entirely. This is a “carbine”, despite going past the arbitrary 20 mm limit.

Edited January 23, 2019 by DDE

[ARS]

1 hour ago, DDE said:

This thing, made from rejected 23 mm AA gun barrels

Ah, the KS-23, the shotgun with the largest caliber, with multiple shell types, which consists of "Shrapnel" buckshot rounds with a 10- or 25-meter range, "Barricade" slugs to destroy the engine block of a car at 100 meters, "Volna" and "Strela" training or less-lethal rounds, and "Bird cherry" and "Lilac" tear-gas grenades, which use a rifle grenade adaptor

Though to be fair, when we are talking about caliber for shotguns, it's rather different story compared to other firearms, mainly despite it's large caliber, shotgun shells usually have low chamber pressure, so even with a caliber of 23 mm, shotgun shell is generally useless when firing at aircraft when compared with other 20 mm caliber guns (Above the Heavy machineguns, the classification goes to Autocannon, which has caliber ranging from 20-60mm)

So yeah, like what @DDE said, it mucked things up

Edited January 23, 2019 by ARS

[BillKerman123]

I'm designing a nuclear upper stage for the SLS (to replace the EUS), and I have two unrelated questions:

1 - What are the dimensions for the Pebble-bed NTR listed on the 'Atomic Rockets' website?

2 - Does anyone know the dry and wet masses of the SRBs, and also, the wet mass of the core after SRB burnout?

[Mad Rocket Scientist]

11 hours ago, BillKerman123 said:

[...]

2 - Does anyone know the dry and wet masses of the SRBs, and also, the wet mass of the core after SRB burnout?

https://www.nasa.gov/sites/default/files/atoms/files/8690_sls_solid_rocket_booster_fact_sheetfinal03072015_508.pdf

1.6 million lbs wet. (Keeping with lbs, since it's probably an approximate number) I can't find anything exact for dry mass, but you could approximate from the space shuttle SRBs, since the SLS SRBs are the same as the shuttle ones with one extra segment.

[ARS]

On 1-1 battleship duel, if one battleship (with sheer luck) managed to land a main gun shell on another's bridge, causing it to explode and completely destroying the bridge, does it becomes an ship equivalent of "headshot"? Does it disables the ship, heavily crippling it or not a big deal at all and still combat capable? Especially since the bridge is the command center of the entire ship

[p1t1o]

56 minutes ago, ARS said:

On 1-1 battleship duel, if one battleship (with sheer luck) managed to land a main gun shell on another's bridge, causing it to explode and completely destroying the bridge, does it becomes an ship equivalent of "headshot"? Does it disables the ship, heavily crippling it or not a big deal at all and still combat capable? Especially since the bridge is the command center of the entire ship

A big deal but still combat capable.

A turret could keep fighting on its own for example. But fresh orders, coordination, navigation and communications with fleet would become a problem, although I would imagine that there are backups for each of these for this event.

One should not that battleship bridges were heavily armoured, the bridge would have an inner, armoured bridge for  use in battle:

https://foxtrotalpha.jalopnik.com/iowa-class-battleships-had-vault-like-conning-towers-bu-1737002503

Edited January 25, 2019 by p1t1o