Got a Real-World Weapon, Armor or Tactics Question? Mk. XVIII

[Telok]

@Carl. We are certainly misunderstanding each other somewhere. I get that the output of this substance or machine is an IR laser, and it's purpose is to cool a spaceship without jettisoning mass. So you need to convert the thermal energy of the ship's components into radiant IR energy. This is usually done with heatsinks and radiators. So what are the properties of this thing, it's input, and how is it supposed to be better than a radiator?

[MrZJunior]

Machine guns are the king of battle in open spaces. If your field of vision only extends a few yards because of heavy jungle, and an enemy can approach very close, then the squad with repeating carbines can approach and flank your big, slow, heavy gun and overwhelm you. Try carrying an early 20th century machine gun and the huge amount of ammo it needs through the undergrowth. That's why I suggested a Lewis gun. One man can carry it over his shoulder. Distribute magazines among the rest of the squad who all have nice light carbines, and you're golden. You can move, attack, retreat and so on.

If you have a hundred yards of clear field of fire in front of you, prepare machine gun positions. If you plan to have sudden shootouts at a range of ten yards, not so much.

Jungle fighting is a lot like house to house fighting. Look at what the troops carried in Iraq. Medium or heavy machine guns were to defend static positions or on vehicles, not lugged by infantry patrols. Even the M16A2, which is very light rifle, was replaced by the shorter M4, because nobody cares about having less range and accuracy when you are having a shootout in an 8x10 room.

If I had to take a machine gun position over 500 yards of No Man's Land, I would worry if I only had 100 riflemen. In the jungle, I'd feel ok with a four man fire team.

Been to Parris Island, went to infantry school, studied this kind of thing.

I apologize if anything I said was taken as questioning your qualifications, I did not intend any disrespect. I wanted to try and clear up the disagreement between the various pieces of advice I have been given.

[Broken Crown]

@Broken Crown: How about actually looking how active cooling systems actually work before spouting nonsense.

That's pretty rich. How about addressing the issues I raised? Such as, first of all, explaining why you think active cooling eliminates the need for large radiators? You keep dodging this question, in spite of it being your original point of contention with my post, and I'm frankly out of patience.

I know how active cooling works. If you read my earlier post, you'll note that I was asking you what you meant by active cooling in the context of "laser resistant armour", and pointing out that it produces extra waste heat.

the only heat generated would be by the pumps.

And how much heat would that be? It depends on the power and efficiency of the pumps, doesn't it? If you're moving large masses of fluid (which you would need to move large amounts of heat, as heat capacity is proportional to mass) at "insane" flow rates (and what flow rate to you consider "insane"?) then you need powerful pumps.

Also, as I pointed out, adding this cooling system will also require the ship to generate more heat, because, to reiterate, it's heavy, so the ship will require more thrust in order to maneuver.

It's like saying your car radiator's cooling generate more heat than the engine it's cooling. It doesn't, in fact aside from the negligible heat from the pump it generate's nothing.

Except that we're not talking about a car, are we? Compared to a spaceship, a car doesn't have any trouble getting rid of heat. Look at the International Space Station. Compare the size of the radiators to the size of the station as a whole. The ISS uses about 90 kW of power (or about 120 hp; a lot less than most cars). It also uses active cooling. In space, 90 kJ is not a "negligible" amount of heat to have to get rid of.

Your confusing forced cooling with thermocouples and the like with what i'm talking about.

Given that I haven't even mentioned thermocouples in this thread, I don't think I'm the one who's confused, here.

Anyway, I'm afraid that I must take my leave of this conversation for the time being, as my computer is dying and I need to take it to the shop. I don't think the debate was going anywhere productive in any case.

[Mr. Mask]

Gnoman: How would I prove the Tiger isn't useless when you only trust evidence which favours your standing, as when you argued with G?

Germany had the upper hand consistently and consistently outdid them. Saying that is conclusive proof that a group of Germans never faced situations where they lacked the necessary firepower to deal with a T34 effectively is ludicrous for any large scale war.



Speaking of the world wars, does anyone know of cases of the Henry Rifle or other repeaters being used by infantry in World War 1?

[Mike_G]

I apologize if anything I said was taken as questioning your qualifications, I did not intend any disrespect. I wanted to try and clear up the disagreement between the various pieces of advice I have been given.

No, no. I'm not insulted, and I wasn't trying to imply that you ha d slighted me.

I just had an issue with whoever said a machine gun has the firepower of "a thousand riflemen," because that's very misleading.

It has the theoretical firepower of many riflemen. It has a greater effective range and with a tripod or bipod or carriage mount has a greater effective accuracy, and can put more rounds downrange.

But most of that means diddly squat in close terrain, while its weakness, maneuverability, means a whole lot.

It's like saying a sniper rifle has much more firepower than a snub nosed revolver. That's true, but if you are having a shootout in a crowded elevator, you want the revolver.

Jungle means close range, short sight lines, lots of cover, all of which hurt the HMG/MMG and help the dispersed rifleman trying to flank it. And it's hard to walk through even if you aren't carrying a sixty pound gun and a twenty pound tripod and ten pounds of ammo. And if you are supplying by airdrop, weight of the load matters. For a mobile, light infantry jungle force I'd take the Vickers' weight in shotguns or carbines any day.

[rs2excelsior]

Regarding the space combat radiator discussion, there's a site that's absolutely essential for this kind of thing. Although be warned: it shoots holes in a lot of classic space opera tropes.

Relevant to the discussion:
http://www.projectrho.com/public_htm...Heat_Radiators
http://www.projectrho.com/public_htm...on--Efficiency
http://www.projectrho.com/public_htm...modynamics.php

It's a wonderful site, check it out.

[Gnoman]

Gnoman: How would I prove the Tiger isn't useless when you only trust evidence which favours your standing, as when you argued with G?

All you need to do is cite a single battle backed up by both German and Allied records where the Tiger proved a decisive advantage compared to a StuG or Panzer IV. THe problem is that you cannot do this. The Americans fought Tiger Is less than a dozen times in the entire war - reports of "Tigers" were almost invariably proven after the war to be Panzer IV tanks, which look quite similar. In every case, the Tigers were destroyed with very little trouble.

The British first encountered the Tiger early - killing their first Tigers with 6-pounder and 2-pounder antitank guns at range in North Africa on February 1, 1943. Tests showed that the only anti-tank weapon that could not reliably defeat a Tiger was the obsolete 2-pounder - the 6 pounder (with the early, less capable ammunition) required careful aim, and anything bigger did not.

The USSR was so contemptuous of the Tiger that they made anti-tank capability dead last on their design priority when they upgunned the T-34 and designed the IS series of tank - the guns already in service were more than adequate, so they went for the highest HE charge instead.

The ONLY sources that support the notion that a Tiger was a superweapon, or even an adequateweapon, are post-war histories that, on the opening of the German archives, did not vet what they were looking at properly for accuracy and thus took boasting claims that were impossible (One Tiger commander claimed to have killed 30 Shermans on a day when none of the Allied Powers HAD any Shermans within 300 miles) at face value because they hadn't yet found the "Ignore this, but use it for propaganda" files. All of these have corrected the error in subsequent books, but the older material is still out there, and forms the base of most pop-history.

[Mr. Mask]

A battle where the Tiger proved a decisive advantage? They're slightly less rare than unicorns, and making contingency plans for facing them would make slightly more sense than contingencies for unicorns.

I recently read an account of Tigers being impressive from a soldier in an article about that movie, Fury. http://www.theguardian.com/film/film...dict-realistic

Is he just saying the Tiger is impressive for the film's portrayal's sake?

[Gnoman]

A battle where the Tiger proved a decisive advantage? They're slightly less rare than unicorns, and making contingency plans for facing them would make slightly more sense than contingencies for unicorns.

I recently read an account of Tigers being impressive from a soldier in an article about that movie, Fury. http://www.theguardian.com/film/film...dict-realistic

Is he just saying the Tiger is impressive for the film's portrayal's sake?

Have you ever played the "telephone game"? If you haven't, it is a child's game (often played in schools to demonstrate communication problems) in which each member of a group of children whispers a message into another's ear with instructions to "Pass it on". By the time it reaches the end of the line, it's entirely different from the original. Memory works like that - your memories are constantly rewritten based on what you hear, see, are told, and what you tell about the events, particularly with the passage of decades on a subject that is constantly the subject of documentaries, popular films, history books, novels, etc.

Not only this, but the sheer stresses of combat make for very poor memories in the first place. Most soldiers remember battles in snapshots and short clips - the overcooked pork smell of a burned-out tank crew or the explosion of a tanks ammunition might remain indelibly printed forever when firing the shot that killed it was forgotten immediately.

Finally, soldiers on the ground are in an incredibly poor position to correctly identify enemy equipment in the first place. The British Army, for example, reported taking fire from 88mm cannon hundreds of times more often than the Germans actually used 88s. 50mm and 75mm guns were used in the vast majority of cases, but the 88 is what the British feared, and they were all too ready to imagine those fears given life. The same was true for the Tiger. Visually, there is very little difference between a Tiger I and mid-model Panzer IV - the gun's longer, the hull's wider in proportion to the height, turret's a slightly different shape, and several other differences - but these are not obvious ones. The main identifying characteristics are the same, and you're not likely to get a good look at the thing until you've already killed it, at which point you don't care what it was - only thing that matters is that it is dead and you are not. Thus rumors of the rarely encountered German supertank carrying the bogeyman 88 and invulnerable to anything short of a battleship spread from unit to unit, aided by fragmentary intelligence briefings that contained little more than images (sometimes pictures of Panzer IVs were used by mistake!) and assurances that the weapons available would do the job - which most soldiers ignored, because they *knew* the tank was invincible.

On the other side, there are many German diaries from the African period that attribute the same bogeyman status to the British's new M4 - describing it as an almost invulnerable supertank that carried a gun capable of smashing through anything they could throw at it.


Incidentally, I suspect that Fury was written to use a Tiger II for that climactic battle - Tiger Is had mostly gone the way of the dodo by that time, and Fury (a 76mm Sherman) scored several square hits that would have penetrated a Tiger I's frontal armor but not a II's- but the opportunity of using a real Tiger came up and they simply substituted.

[Mr. Mask]

Which brings it back to my original point. Because soldiers' accounts are capable of error, you won't accept accounts from soldiers', except when they attest the Tiger to be useless. I don't doubt that there was plenty of confusion going on around troops, but that doesn't disprove all accounts of the Tiger being an effective tank.

How close was the Fury to the Tiger when it scored its hits (can't remember)?

[Gnoman]

Which brings it back to my original point. Because soldiers' accounts are capable of error, you won't accept accounts from soldiers', except when they attest the Tiger to be useless. I don't doubt that there was plenty of confusion going on around troops, but that doesn't disprove all accounts of the Tiger being an effective tank.

I don't accept soldier's reports at all unless they are backed up by loss records, salvage records, photographic proof, reports from both sides, or at least some evidence that the tanks in question actually existed. This is a good example of what I consider a reliable source - the blog author cross-checked the Soviet claims with german reports and found that they matched, while here is a good example of why reports from only one side are useless - the German reports claim that their attack completely destroyed the enemy (while reporting losses only in that the Tigers Available number goes from 18 to 3), while the Soviets claim 13 tanks destroyed with minimal losses.

EDIT: As for the Fury, it was very close in the movie - I don't recall an exact figure given, but it can't have been more than 500 yards given how quickly they got behind the Tiger.

[Brother Oni]

All you need to do is cite a single battle backed up by both German and Allied records where the Tiger proved a decisive advantage compared to a StuG or Panzer IV. THe problem is that you cannot do this. The Americans fought Tiger Is less than a dozen times in the entire war - reports of "Tigers" were almost invariably proven after the war to be Panzer IV tanks, which look quite similar. In every case, the Tigers were destroyed with very little trouble.

Are you saying that you believe that the Battle of Villers Bocage and Micheal Wittmann's record are just overblown propoganda?

While I agree that often the Allied soldiers over-reacted to every German tank, assuming they were a Panzer or a Tiger when they weren't, there's a sufficient reports where a Sherman scored a direct hit on a German tank only for the shell to bounce off, to lend some credence to their reputation.
On the German side, I know they quickly learned to distinguish between a regular M4 and the M4 with the longer cannon that could punch a hole through anything (the Sherman Firefly).

I'll have to do some research on what sort of tanks, but I know that tanks were crucial to finally defeating the British forces entrenched in at Arnhem bridge during Operation Market Garden.

Edit: I just remembered I found an ARR of Shermans vs a pair of Tigers for a previous version of this thread, where a Sherman hid behind a building and nailed a Tiger in the fuel tank as it passed by, so while I agree with Gnoman that the mythical reputation of Tigers is somewhat overblown, it's still an intimidating tank from the actions of the Sherman commanders during that engagement. I'll see if I can find it again.

Edit 2: Still looking for the ARR, but I found an earlier post by Galloglaich that suggests a small number of Tigers among the other AFVs, were instrumental to the Allied rout during the Battle of Kasserine Pass.

[Gnoman]

Are you saying that you believe that the Battle of Villers Bocage and Micheal Wittmann's record are just overblown propoganda?

The extent of Whittmann's role in the battle is unclear - the losses are known, but it is not certain precisely what happened - Whitmann's account, the British account, and the official German account differ quite a bit, including precisely where Whitmann's tank was disabled. Still, it is true that this is one engagement where the Tiger's gun and armor made a major contribution.

While I agree that often the Allied soldiers over-reacted to every German tank, assuming they were a Panzer or a Tiger when they weren't, there's a sufficient reports where a Sherman scored a direct hit on a German tank only for the shell to bounce off, to lend some credence to their reputation.
On the German side, I know they quickly learned to distinguish between a regular M4 and the M4 with the longer cannon that could punch a hole through anything (the Sherman Firefly).

This is oft cited, but nobody seems to be able to prove it - British tank units show no significant loss differences between Firefly and non-Firefly tanks. If the Germans cared what model of M4 they were fighting, the more dangerous ones would be target preferentially, which no evidence supports.

Edit 2: Still looking for the ARR, but I found an earlier post by Galloglaich that suggests a small number of Tigers among the other AFVs, were instrumental to the Allied rout during the Battle of Kasserine Pass.

Kasserine Pass took place in February of 1943. At that point, the Tiger had been in production since August of the previous year, producing 25 tanks per month for for ~7 months. That translates to a maximum total of 175 Tigers on all fronts - this includes full production for the beginning and end months, which is unlikely. A large percentage of this were sent to the Eastern Front - we'll say half the total. That leaves no more than 90 Tigers for the entire North African theatre. The Tiger was unreliable - it was rare for a Tiger unit to have half their vehicles running, particulalry in the desert as the first batches of Tigers had air filters that didn't handle sand too well. That leaves 45 combat-effective vehicles outside the Eastern Front. Let's assume every last one of them was at Kasserine Pass. The Germans deployed over 200 tanks to that series of battles. The Panzer III and IV made up the bulk of them by far - and there's no evidence that the Tiger performed better than those two models in the battle - it is unlikely that that would have mattered as the US Army drove straight into a trap and was engaged by flanking tanks and heavy anti-tank guns. Any tank would have done well in that sort of battle, and the Wehrmacht were masters of setting it up.

[Carl]

@Brother_Oni: Ahh cheers, yeah i'm pretty sure that would be useless in practise because the material's too thin to resist wear and tear of bump and knocks and catching on stuff. That's why i mentioned cold water diving suits, apart from space suits also needing to cool if the astronaut is in sunlight instead of shade as you mentioned, and the pressure differential they have to deal with they have many of the same requirements. Short of a new material coming in any realistic space suit that's sufficiently hard to damage accidentally, (let alone a military grade one that has to stand up to shrapnel and the like), is going to require thick enough material that there shouldn't be any issues, (you could take extra measures if needed but i doubt it would be).

@Broken crown: Instead of parroting the wiki do research and actually apply your brain to the problem. If you had done that you would allready know that electric motor driven pumping systems are remarkably efficient. Given all the other source of heat on a spacecraft, especially on a military ship under attack the pumps are not going to be a significant amount of extra heat.

Also i answered how you get rid of the heat in the initial premise. The armour of the ship IS the radiator. You just switch that part under attack to cooling mode when it gets hit. You certainly would need some dedicated structures for certain types of waste heat where you want to radiate at maximum thermal temperature and the like. But for many general purpose circumstances the same system that can carry away the heat of a laser attack will be able to dump heat to space. It all depends on certain parameters. It's not going to be as god as a dedicated radiatir because the surface area won;t be optomised. But it's still bloody useful because again, it lets you turn what would otherwise be non-radiating surface area into radiating surface area.

@Telok: No worries. I'll try and lead you through the basics,.

The concept is inspired by the earliest models of laser. These used a material, (i think neodymium was the first then CO2, but i'd need to double check my sources for the progression and names to be sure), in a tube and then using what amounts to a super powered camera flash to dump light into it. The material absorbs the light and then re-emits it as coherent light, a percentage is lost and become heat.

The concept is to take the same general principle but do it with infrared radiated from the walls of the lasing tube, (which unlike a ship exterior can be any shape you desire to maximize emissions area), in normal radiator fashion and with a material that then outputs that. Thermodynamics says it would have to be a frequency of IR output, you can''t turn IR into UV AFAIK. But you can turn it into a different form of IR. Not all of the IR you dump in will go away, a lot will remain trapped in the system so you have to carefully control how much heat you dump in and without a much better efficiency than those early lasers you won't get very good output. But it allows you to turn internal volume into radiator area. That's bloody useful so long as the efficiency isn't too bad.

Does that help?

[Brother Oni]

This is oft cited, but nobody seems to be able to prove it - British tank units show no significant loss differences between Firefly and non-Firefly tanks. If the Germans cared what model of M4 they were fighting, the more dangerous ones would be target preferentially, which no evidence supports.

I'll see if I can find a reference, but in the mean time, here's an account of the engagement I mentioned earlier: link.

Of note is the fact that a direct hit on the front lower hull of a Tiger at a distance of 75-100 yds from a 75mm Sherman did minimal damage to the Tiger, however a 20-30yd shot later on penetrated the Tiger's thinner side armour.

The Panzer III and IV made up the bulk of them by far - and there's no evidence that the Tiger performed better than those two models in the battle - it is unlikely that that would have mattered as the US Army drove straight into a trap and was engaged by flanking tanks and heavy anti-tank guns. Any tank would have done well in that sort of battle, and the Wehrmacht were masters of setting it up.

I'm not as familiar with the North Africa campaign, so if you're right in that the evidence is minimal or non-existent, I'll defer to you.

@Brother_Oni: Ahh cheers, yeah i'm pretty sure that would be useless in practise because the material's too thin to resist wear and tear of bump and knocks and catching on stuff.

I'm not so sure that it's completely useless given that NASA and MIT are still working on the concept nearly 40 years later.

[Gnoman]

I'll see if I can find a reference, but in the mean time, here's an account of the engagement I mentioned earlier: link.

Of note is the fact that a direct hit on the front lower hull of a Tiger at a distance of 75-100 yds from a 75mm Sherman did minimal damage to the Tiger, however a 20-30yd shot later on penetrated the Tiger's thinner side armour.

This is exactly as expected - the 75mm was never intended to remain the primary gun for as long as it did (production had shifted entirely to the vastly superior 76mm before the US had ever heard of the Tiger), but it was decided there was no need to replace the ones already in theatre because they were proving to be more than good enough for everything they were fighting at the time (including Panthers and the occasional Tiger, as in both the African and Italian campaigns the German armor was easily outflanked, and it wasn't until the battles in France after OVERLORD that the German tanks were able to use their oversized guns and excessive frontal armor to good effect). While a 75mm could theoretically have penetrated at that range with a square hit, the round fired was a snapshot that's almost guaranteed to hit at an angle horizontally, and firing at the lower plate at that range would have given it a vertical angle as well.

[PersonMan]

Somewhat related to a question I asked a few days ago, on sustainable losses for modern militaries:

1. Roughly how much time is necessary to turn a batch of recruits/conscripts/whatever into combat-ready soldiers? How many corners can you cut before your troops are at a noticeable disadvantage to properly-trained ones?
2. How large is the difference between green and veteran soldiers on the battlefield? How much does this change if the green troops have only a shortened training period behind them?

Only somewhat related:
3. What sort of effect can reputation have on morale? If we're dealing with soldiers who believe themselves to be going up against indestructible tanks, or an unbeatable force, can this belief be used to break them and ensure an easy victory?

[SowZ]

Somewhat related to a question I asked a few days ago, on sustainable losses for modern militaries:

1. Roughly how much time is necessary to turn a batch of recruits/conscripts/whatever into combat-ready soldiers? How many corners can you cut before your troops are at a noticeable disadvantage to properly-trained ones?
2. How large is the difference between green and veteran soldiers on the battlefield? How much does this change if the green troops have only a shortened training period behind them?

Only somewhat related:
3. What sort of effect can reputation have on morale? If we're dealing with soldiers who believe themselves to be going up against indestructible tanks, or an unbeatable force, can this belief be used to break them and ensure an easy victory?

Let me amend the third point with, "How much of a difference does having a famous and beloved general make, even if that general's tactics are no better or worse than the next guys?" How much of a morale difference does fighting beside a well known, Srgnt. York style war hero make?

[Gnoman]

Somewhat related to a question I asked a few days ago, on sustainable losses for modern militaries:

1. Roughly how much time is necessary to turn a batch of recruits/conscripts/whatever into combat-ready soldiers? How many corners can you cut before your troops are at a noticeable disadvantage to properly-trained ones?
2. How large is the difference between green and veteran soldiers on the battlefield? How much does this change if the green troops have only a shortened training period behind them?

1. This depends a lot on what you're starting with. Educated civilians turn into soldiers more readily than ignorant ones because they're used to learning things, and if a particular military skill is particularly common in your recruit pool you can often skimp on it. As a general reference, the USMC currently uses a 13 week program, in WWII the standard was 8 weeks, and the need for troops caused it to be halved to 4.

2. Massive - just read a few posts up about what happened when a green American unit ran into German veterans in Africa, for example. Lower-quality training makes things much worse, but the most important battlefield skills simply can only be taught to a man by trying very hard to kill him.

[Mr. Mask]

Well, it depends how combat ready the conscripts were to start with. If they're frontiersmen from the tough part of the country, they probably only need a few weeks of drill so they're organized into a cohesive unit. If they're people with no background of violence whatsoever, you're going to get less robust results and it'll take longer.

The difference between untrained semi-combatants and warriors can get pretty tremendous. Who was the American fellow who caused a whole platoon of Germans to surrender? He wasn't even interested in the war, until his own unit came under attack and he decided to defend it. There was also the fellow who held off a similarly large contingent of Germans with a machine gun, which was on a tank, which was on fire. Some of that is dumb luck, but you need a capable soldier in position to take advantage of that luck, or else it'd not make much difference (if they panic fire and don't hit anything with the MG, they won't hold off many enemies). And as Gnoman says, you get cases like the Italians against the British, the first American battles against the Germans.


Morale is an interesting subject, and it really depends on a lot of political and social factors. Is it socially acceptable to join the other side? That has been common enough in history, even when it wasn't socially acceptable. Will the enemy burn your homes and genocide your people? That has also been common in history, and often inspires men to fight to the death regardless of odds (assuming there isn't a comfortable means of escape for them and their families). Will the enemy offer them decent conditions if they surrender and not perform atrocities against civilians? That is a big incentive to surrender rather than fight, particularly if there isn't a lot of loyalty to the current government.

As for the effects of reputation, it certainly has an effect. The British and US troops seemed to like Rommel, being more interested in what he was doing than their own generals. If men were undecided as to whether to surrender or fight, their enemy being renowned and undefeated would certainly sway them towards not fighting. Some castles have surrendered by that very merit, that other castles did not stand for long against a given conqueror.

Your own general's reputation certainly can have a great effect. Soldiers will follow a leader they respect into death. At the Battle of Gettysburg, the Confederates charged some very well defended positions that'd make most men baulk, and they reportedly offered to charge again after they were forced back with terrible casualties. That was the kind of trust and respect they had for General Lee and their other officers (before, they used to call him Granny Lee).

[Storm Bringer]

Somewhat related to a question I asked a few days ago, on sustainable losses for modern militaries:

1. Roughly how much time is necessary to turn a batch of recruits/conscripts/whatever into combat-ready soldiers? How many corners can you cut before your troops are at a noticeable disadvantage to properly-trained ones?
2. How large is the difference between green and veteran soldiers on the battlefield? How much does this change if the green troops have only a shortened training period behind them?

Only somewhat related:
3. What sort of effect can reputation have on morale? If we're dealing with soldiers who believe themselves to be going up against indestructible tanks, or an unbeatable force, can this belief be used to break them and ensure an easy victory?

1. modern british army basic training takes about 3 months, and gets you blokes who can stay alive in the field, know what to do when shot at and can hold a rifle without shooting themselves. Infanty get another 6 months on top of that, which covers things like weapons other than a rifle, advanced patrols, assaults, FIBUA, etc. So, for a lorry diver, for example, 3 months, and a infantry tom, about 9 months. not sure how much you can cut form that before things get really ropey. I was hardly chuck norris after three months of basic. some things just take time to sink in.

2. In short, big. no matter how good and realistic the training, some thin gs can only be learnt the hard way. some lessons are quite simply fatal, and a lot of things are "like riding a bicycle": you can't really explain it, you just gotta learn how to do it. however, the relevance of the experenice matters. years of experience patrolling northen ireland is only of so much use in southern Iraq.

3. yes, it can, and has been used in history. Napoleon famously said "the moral is to the physical as the three is to one". empires like Rome often relied on thier reputation to deter potential attackers: why attack a foe that you know is not going to rest until you are dead? the Mongols made a point of being over the top brutal and savage when they attacked a enemy, with the aim of convincing their next target to lay down and surrender (and thus saving everybody a lot of time, money and lives). People faced with a enemy they can't beat, or even hurt, will tend not to stand and fight if any other option is available.

Let me amend the third point with, "How much of a difference does having a famous and beloved general make, even if that general's tactics are no better or worse than the next guys?" How much of a morale difference does fighting beside a well known, Srgnt. York style war hero make?

Again, lots. The is another old saying to the tune of "donkeys led by lions are more dangerous than lions led by donkeys". people will follow a leader who they trust, and will take risks for a leader they trust, because they know he isn't going to squander thier efforts. In 1917, the french summer offensive was a massive failure that cost many casulties for minimal gains. Many troops mutinied, and refused to attack. They were still willing to fight, though, and defended thier lines with suffcient vigor to prevent the germans form realising the scale of the problem. they just wanted a leader they could trust in, plus a few improvments to working conditions (in line with what the brits and germans provided their troops). A new french supreme commander was appointed, one with a reputation for looking after his men, and who the troops liked (cant remember his name for certain. Petian?). This, plus a few well placed crackdowns, solved a threat that could have caused the french front to collapse.

[fusilier]

Again, lots. The is another old saying to the tune of "donkeys led by lions are more dangerous than lions led by donkeys". people will follow a leader who they trust, and will take risks for a leader they trust, because they know he isn't going to squander thier efforts. In 1917, the french summer offensive was a massive failure that cost many casulties for minimal gains. Many troops mutinied, and refused to attack. They were still willing to fight, though, and defended thier lines with suffcient vigor to prevent the germans form realising the scale of the problem. they just wanted a leader they could trust in, plus a few improvments to working conditions (in line with what the brits and germans provided their troops). A new french supreme commander was appointed, one with a reputation for looking after his men, and who the troops liked (cant remember his name for certain. Petian?). This, plus a few well placed crackdowns, solved a threat that could have caused the french front to collapse.

Yes it was Petain. Who sadly would be so discredited by his actions during WW2, but during WW1 was a sensible general, who believed that attacks that failed should be called off -- many of the other French commanders were willing to lie to their troops and order many useless assaults. Which undercut the trust the soldiers had in their superiors.

I would point out that "motivation" is sometimes a key factor -- there are historical examples of highly motivated soldiers defeating much more disciplined and experience soldiers. There are so many factors in combat that it's hard to reduce failure/success to just one, although often people attempt to.

There was a comment about Italian soldiers versus British up thread that I wanted to address briefly: during the North Africa campaign (especially the early phases), Italians surrendered in large numbers to the British forces there. This is usually interpreted as poor morale, or a poor fighting spirit -- but that wasn't the whole story. The fact of the matter was the Italian army lacked the mechanized transport to move their soldiers fast enough to respond to threats, and, perhaps more importantly, lacked the means to supply water to their soldiers. When Commonwealth and German soldiers found themselves in the same position (cutoff with no water or transport), they surrendered just as readily -- it's just that the Italians found themselves in those positions a lot more often.

The point is that there are many factors that should go into the analysis that don't often make it. Instead there's a tendency to reduce it to one or two. The British made this mistake after the opening North Africa battles, assuming that the Italians simply lacked fighting spirit. While poor morale was a factor, there were other organizational and supply issues that should have been considered. It's not uncommon in the description of later battles to read something like "the Italian divisions put up unexpected resistance." A clear indication that they had misread the earlier battles.

[Gnoman]

There was also the fellow who held off a similarly large contingent of Germans with a machine gun, which was on a tank, which was on fire.

Audie Murphy.

[Carl]

@Brother_Oni: From what i can tell the proposed suit has some significant constructional differences that should allow for a much more rugged outer layer. It has some basis in the old suits but it's not just an upgraded version thereof. Because the force is applied mechanically rather than via the material itself a much wider array of materials can be used with corresponding durability benefits. Weather it can go far enough is an open question, but i suspect if someone gets their brain in gear and stops relying on "what everyone knows" it will be easy, (i can think of 2 or 3 concepts right now for adding such damage resistance on with a minimal mobility cost).

[Telok]

The concept is inspired by the earliest models of laser. These used a material, (i think neodymium was the first then CO2, but i'd need to double check my sources for the progression and names to be sure), in a tube and then using what amounts to a super powered camera flash to dump light into it. The material absorbs the light and then re-emits it as coherent light, a percentage is lost and become heat.

The concept is to take the same general principle but do it with infrared radiated from the walls of the lasing tube, (which unlike a ship exterior can be any shape you desire to maximize emissions area), in normal radiator fashion and with a material that then outputs that. Thermodynamics says it would have to be a frequency of IR output, you can''t turn IR into UV AFAIK. But you can turn it into a different form of IR. Not all of the IR you dump in will go away, a lot will remain trapped in the system so you have to carefully control how much heat you dump in and without a much better efficiency than those early lasers you won't get very good output. But it allows you to turn internal volume into radiator area. That's bloody useful so long as the efficiency isn't too bad.

Does that help?

Right. The old gas lasers. I got to play with one as part of a student project back in the early 90s. Three inches by three inches by three feet, it plugged into the wall socket and had a noisy fan blowing across a heatsink in it. Probably about as powerful as a handful of the cat toy laser pointers today. Horrible efficiency.

So you are putting your radiators on the inside of a box inside the ship, using normal thermal->IR methods to power a laser, and hopefully the increased mass and loss of efficency isn't too bad.

Try the wikipedia on lasers. It will help in understanding the issues here. What you're advocating is adding another step to the heat dumping process, more inefficency, more mass, more complexity... Your laser output isn't limited to IR wavelengths, it's based on what you build the laser out of. The laser being a tube is pretty common because it simplifies all sorts of things, a non-linear optical resonating cavity would be... interesting to design.

I'm still trying to understand why increasing the size and mass of a spaceship to put the radiators on the inside, in order to power a laser, is a good thing.

[Carl]

Telok: I don't need to go read the wikipedia, i have reference books that make wikipedia's info largely useless as they're more complete unless it's something fairly recent.

A great example of this is that old laser you saw. That's a great example of the very first generation teribble output efficiency examples. They've built much more efficient and/or powerful, (depending on the exact type and example under discussion), lasers than those, they'd done it by the nineties but well that one you know was probably either a very old piece of kit or the equivalent of the various low grade particle accelerators some universities have. Namely not remotely comparable to the state of the art.

Your laser output isn't limited to IR wavelengths

It is if the input energy is IR, anything else would violate thermodynamics as i understand it. You can't turn heat into another EM frequency. Entropy and all that.

I'm still trying to understand why increasing the size and mass of a spaceship to put the radiators on the inside, in order to power a laser, is a good thing.

What part of you've got limited surface area externally is hard to understand?

In addition any lasing medium should have vastly high heat transfer rates than open space. Meaning that unit area for unit area you get a significant multiplier over open space radiators. In practise system efficiency will bleed off all that advantage, but even if your efficiency is such that you need 10 square meters of lasing medium surface area for every square meter of hull area you can get literally hundreds of square meters of surface area per cubic meter if you can build the lasing and coolant channels thin enough. But even if you've got only a couple of square meters extra cooling per cubic meter you can have as many cubic meter's dedicated to cooling as you have square meter's of surface area and still thanks to square cube law have huge amounts of internal space.

To throw up an example lets say each cubic meter of lasing volume is worth 3 square meters of surface area. Now lets assume a ship that is a cube 20m a side. Providing extra cooling via lasing medium equal to your surface area only requires 10% of your internal volume. (volume of 8,000M^3 surface area of 2400m^2, 800m^3 to match 2400^2 at a 3 m^2 per 1m^3).

[Yaktan]

Yeah, the big problem with trying to use lasers to cool stuff off is that you need a power source. Because of how light absorption/emission works, you cannot get a laser working by just inputing the light you want amplified. (also, no perpetual motion lasers) While I think cooling lasers would be cool, they seem quite impractical.

[Hjolnai]

I'm not entirely sure that spaceship cooling is such a major problem. Your standard heat-removal method is black body radiation, which is proportional to absolute temperature^4 (but only linearly proportional to surface area). If your hull has a high enough melting point (steels tend to be around 1700-1800K, I think, while tungsten is more than twice that - although tungsten might not be suitable in other ways), and you have good enough insulators, then heat removal is very rapid when it needs to be.

If you also thermally isolate sections of hull, then you can use a heat pump to push internal heat to the cooler hull sections while the hotter ones disperse the heat from weapons. Heat pumps become less efficient when trying to push through too much temperature differential, so you can't push your internal heat out to the already hot sections.

Of course, I'm not an engineer and I haven't run the numbers, so you can take this with a grain of salt. Also, if the temperature is instantly spiked high enough to melt your hull, it's too late for anything else to help except ablative armour.

[Carl]

I'm not entirely sure that spaceship cooling is such a major problem. Your standard heat-removal method is black body radiation, which is proportional to absolute temperature^4 (but only linearly proportional to surface area). If your hull has a high enough melting point (steels tend to be around 1700-1800K, I think, while tungsten is more than twice that - although tungsten might not be suitable in other ways), and you have good enough insulators, then heat removal is very rapid when it needs to be.

If you also thermally isolate sections of hull, then you can use a heat pump to push internal heat to the cooler hull sections while the hotter ones disperse the heat from weapons. Heat pumps become less efficient when trying to push through too much temperature differential, so you can't push your internal heat out to the already hot sections.

Of course, I'm not an engineer and I haven't run the numbers, so you can take this with a grain of salt. Also, if the temperature is instantly spiked high enough to melt your hull, it's too late for anything else to help except ablative armour.

One of the links earlier in the thread covered this. A) you can only reject heat at the temperature the coolant is at which can't be higher than system operating temperatures. In short electronics and life support are all going to be fairly low, (270-320 kelvins or so off the top of my head), temperatures which makes rejection rates very low, (a few hundred watts per square meter). B) trying to use thermocouples to force he heat into a high temperature output gets thermally very expensive very fast.

Yeah, the big problem with trying to use lasers to cool stuff off is that you need a power source. Because of how light absorption/emission works, you cannot get a laser working by just inputting the light you want amplified. (also, no perpetual motion lasers) While I think cooling lasers would be cool, they seem quite impractical.

Well no one's talking about using same frequency. Old school lasers as noted used broad spectrum visible light input and got single frequency visible light output. The idea is just the same concept applied to IR except you can also potentially use single spectrum IR input at a sufficiently different frequency to your output. The power source basically is your waste heat here which is the beauty of the system, your not doing anything that's going to generate excess waste heat, at worst at 0% efficency you just get back everything you put in. At anything above 0% you get some of it back and the rest leaves as coherent IR. though to b fair it wouldn't even have to be entirely coherent so long as your optical cavity can handle a non-coherent output, (tricky as i understand it).

[Telok]

What part of you've got limited surface area externally is hard to understand?

Why is surface area limited? If it's a spaceship you can make huge radiators that fold down to very small size. Surface area is only limited in you want smooth, unbroken, spaceship hulls.

To throw up an example lets say each cubic meter of lasing volume is worth 3 square meters of surface area. Now lets assume a ship that is a cube 20m a side. Providing extra cooling via lasing medium equal to your surface area only requires 10% of your internal volume. (volume of 8,000M^3 surface area of 2400m^2, 800m^3 to match 2400^2 at a 3 m^2 per 1m^3).

That's a small ship, it's smaller than the ISS. It looks like your numbers are probably right but I can't tell what you're describing with them. What is an 8000 cubic meter surface area? Where is the 800 cubic meters coming from?

The volume of the ship is 8000 cubic meters, surface area is 2400 square meters. The magic heat-eating laser is 2 cubic meters and assumed to be equal to the 2400 meters of hull. Sounds wonderful. I'm sure you could build a laser that big today that would use up energy and you could still bolt folding radiator panels to the outside of the ship that would increase the radiant surface area by more than that.

As for the laser, you're expecting to take heat from ship components, turn that into radiant IR, and use that to excite material that gives you the beam. You are probably right that you can't higher energy radiation out of that, I'm not that up on the physics of that part. There's probably some variation on the visible light lasers works in the IR part of the spectrum, which means that this isn't advanced tech. But why do you want to turn the heat into IR inside the ship? At that point you can just assume that you can turn the heat back into work and use that to power the laser or to make your power plant smaller and create less waste heat in the first place.

Really this does sound like just keeping the heat inside the ship to power a laser to get rid of heat. Why does it need to be a laser then? You don't realy care about the form of energy you're expelling, just that you take the heat from your ship's components and radiate it away. It looks like that in order for this laser to work your internal heat->IR converters have to be more efficent than external radiators and then you destroy that efficency by using it to power a laser. At that point you could just put those converters on the hull and get better results.

I'm not seeing any savings in mass or the efficency of expelling waste heat over just using standard radiators. What's the benefit here? Nicer looking spaceships? Fancier technology?