ARS

@K^2, @kerbiloid I see, thanks for the answer

Is it possible to have a nuclear thermal rocket with the engine design that have adjustable thrust level and effiiency in the atmosphere? high-thrust low-efficiency at low altitude before gradually switching to low-thrust high efficiency at high altitude, by adjusting the nozzle diameter and the level of fission heat? For high thrust-low efficiency, the nozzle diameter becomes smaller while the fission heat level increases (yielding high gas pressure in the chamber). For low thrust-high efficiency, the nozzle diameter becomes larger while the fission heat level decreases (yielding low gas pressure in the chamber)

@monophonic, @JoeSchmuckatelli So what this means is that, they fly outside the conflict zone at high altitude, yet their radar and sensor still has enough range to reach inside the contested airspace to assist the allied aircrafts?

Why the probabiity of AWACS aircraft being shot down in large-scale air conflict is very rare? Do they fly too high to be targeted or spend the majority of their time very far from action, just using their radar and supporting the allied aircraft?

At which point for a high speed projectile starts to be faster than the eye? Or more appropriately, faster than the brain can process? For example, you're viewing a blank white background, and then a projectile pass before your eyes. How fast the projectile have to travel before it starts unnoticeable by human eye? Does it have to travel faster than the speed of electrical impulse of optic nerve? Or is there lower/ higher speed for such phenomenon?

Why it's very rare to find a missile-launching submarine with forward silo placement (the VLS is placed in front of the sail instead of behind it)? So far what I know is Typhoon-class submarine with forward-mounted VLS , while most other submarine uses rear-mounted VLS. What's the advantage and disadvantage of forward mount VLS? And why it's rarely used?

Probably because on aviation application, the stress on the engine itself is far less compared to being used for maritime application. Looking on Junkers Jumo 205 application history, it's mainly used on slow-moving aircraft (either bomber or patrol aircraft), and their speed is considered slow by today's standard. Pushing a fuselage through air is less demanding than pushing a hull through water (not to mention the air itself helps lifting and maneuvering the aircraft). IT COULD be miniaturized, but I think it would have shorter lifespan compared when being used as aircraft engine because of higher stress in maritime application, and as a result, more replacing/ repairing the engine, which is not economical on the long run

AFAIK, most Russian warships that doesn't use gas-turbine or nuclear propulsion used Mazut as fuel. In the west, this is commonly called "waste oil" and in petrochemical term, Mazut is much like the equivalent of Number 6 Oil (Bunker C), and is part of the products left over after gasoline and lighter components are evaporated from the crude oil. Mazut is considered as "dirty oil", you're supposed to process Mazut with FCC or RFCC process to eventually produce the final product: diesel fuel, although it can still be used as fuel by itself, primarily in large boilers or power generators, since it has a high energy value. The drawback is the thick black smoke it produces (like Admiral Kuznetsov's infamous trails of heavy black smoke)

Ah I see, thanks

So... I've noticed that on early version of steam locomotives, the chimney is tall and big (like the classic funnel-shape chimney) compared with the actual boiler. But then as the steam locomotive gets bigger, the boiler seems gets huge while the chimney gets smaller. Is there a reason for this? Because in theory: bigger boiler = more steam= more exhaust

I wonder how the stabilization would deal with the boat swaying on water

Is that a tank turret mounted on a freakin' boat!?

The days of battleship era was near its end when naval aviation becomes practical and carriers become viable weapons of war, with the main selling point being able to strike battleship far beyond its gun range. After the war, although there's still some battleships around, the doctrine then shifted more from naval gunnery to guided missiles, thus, the battleship era was totally ended when guided missile technology has matured enough to place it on nearly all types of surface vessels, from the smallest to the biggest. Now, I saw some interesting discussion on mobile warship game, basically it boils down to this: Proponents of battleships argue that the main reason the battleship era ended was because the range of engagement gets farther and farther, far beyond their main gun range (the main selling point of a battleship). If the range disadvantage was removed, the battleship couldstand a chance to win if the modern warship is forced on close quarter combat. The battleship's heavy armor will allow it to withstand some missile hits while the main gun could blow the modern warship apart (which is much less armored than WW2 era battlehip) Now, what I find interesting is that the notion that battleship main gun being able to blow a modern warship apart. Now what I want to as is, if the 2 ships encountered each other, and then: 1. The battleship fired a salvo of main gun shells (let's take 9 shells, the most common number of main guns on most battleships) 2. The modern warship (let's say a destroyer), just stand still, not doing anything, except trying to intercept the 9 shells with modern CIWS Does modern CIWS is sophisticated enough to track and destroy an object like incoming battleship shells? If it is, then yeah, the battleship has no hope at all against modern warship

Is it possible to make geostationary orbit on polar region (either north or south)? Or if it's impossible, is there any satellite network design that achieve basically the same result? (continuous survey of the same landscape on polar region) How many satellites (at the bare minimum) required to achieve it?

How SRB being more expensive than liquid fuel rockets when SRB is relatively simpler in design? (no kind of complicated plumbing, valves, fuel lines, cryogenic fuel tanks, etc.)

Does this statement correct? "The solid-fuel rocket provides massive thrust at cheaper price than liquid-fuel rocket, at the cost of its inability to be throttled and turned off once ignited and short operating time. With high thrust to weight ratio, a strap-on solid rocket booster is always a good choice to be added for an extra thrust during the liftoff" Mainly on this part: "...a strap-on solid rocket booster is always a good choice to be added for an extra thrust..." Since SRB usually have high TWR (more than enough to lift it's own mass to pretty high altitude before running out of fuel), strapping them on larger rocket seems like a good idea for "free" extra thrust (strictly speaking from physics standpoint, ignoring cost or other mechanical complexity). However, is there any situation (payload profile, weather condition, a certain point in rocket's total mass. In a sensibly-designed rocket of course) that makes adding a strap-on SRB no longer provides any benefit and instead being detrimental to the mission?

A circle with infinite radius is a line, close to infinity means slightly curved line

Ah I see, so that's before the era of guided missiles when people start to distinguish between the guided/ unguided distinction

Isn't that applies on every rockets and missiles? I thought the missile definition generally means it's guided, while a rocket is the 'less guided' (or unguided) term. People called the V2 as 'rocket' even though by definition it's a cruise 'missile'

Considering the operational parameters, design and operating principle, does V2 considered as a missile or a rocket?

Just like how deforestation affect the change on Earth's climate, could (over)-reforestation (I don't know the term, but essentially too much trees on the planet) push the Oxygen level on Earth's atmosphere to a deadly concentration?

That makes me wonder, how far you can 'compensate' the hardware below system requirement with other hardware (for instance, the RAM needed is 8, but you only have 4, though the processor is I7 instead of I5 system requirement. Or the GPU is below system requirement, but the RAM and processor is way above the system requirement)

It's the grey goo!!

In space, if you use an extremely powerful directional microwave emitter (more than what spacecraft hazard protection designed for), could you actually blow up incoming target (fighters, missiles, ships, etc.) by cooking up their warhead/ ammunition? Or for the short version, could you cause ammo cook-off by using directional microwave? (which in turn, caused magazine detonation)

With such a low-pressure environment, if we're looking for hypersonic realm of speed (from engineering standpoint, strictly about speed, not about it's application on hypersonic ordnance), which altitude is preferrable? Low or high? Since at low altitude, the higher air density makes hypersonic engine (ramjet, scramjet) easier to use since there's plenty of air to feed it, but the aerodynamic heating would be deadly, while at high altitude, the heating might not be as severe as in low altitude, but the thin air might impede the engine's performance