WebDog posted:

DarkCrawler posted:

There were some tacky WWII posters too...

quote:

The second Gloucester (PF-22), originally classified PG-130, was launched on 12 July 1943 at the Walter Butler Shipbuilding Company in Superior, Wisconsin, under a Maritime Commission contract, sponsored by Mrs. Emily K. Ross; acquired and simultaneously commissioned on 10 December 1943.

Nenonen posted:

There were a multitude of solutions, but they normally involved a good deal of calculations, drawings on a millimeter grid, correction charts for wind, temperature, air pressure etc. But still much depended on manual calculations. There were also rules of thumb: eg. "a 10º change of temperature from +15ºC changes range by 5%".

One effective solution to the problems before computers was the Finnish Correction Converter (1943), a piece of plywood with an opaque plastic disc on it. With it the Forward Observer didn't have to know the relative difference in heading of himself and the battery to do corrections. The converter did this in a turn of hand, enabling the FO to easily control the fire of several separate artillery battalions at once.

quote:

Early development

The development of the Sidewinder missile began in 1946 at the Naval Ordnance Test Station (NOTS), Inyokern, California, now the Naval Air Weapons Station China Lake, California as an in-house research project conceived by William B. McLean. McLean initially called his effort "Local Fuze Project 602" using laboratory funding, volunteer help and fuze funding to develop what it called a heat-homing rocket. It did not receive official funding until 1951 when the effort was mature enough to show to Admiral William "Deak" Parsons, the Deputy Chief of the Bureau of Ordnance (BuOrd). It subsequently received designation as a program in 1952. The Sidewinder introduced several new technologies that made it simpler and much more reliable than its United States Air Force (USAF) counterpart, the AIM-4 Falcon, under development during the same period. After disappointing experiences with the Falcon in the Vietnam War, the Air Force replaced its Falcons with Sidewinders.
Geometric arrangement of mirror, IR detector and target.
An AIM-9B hitting an F6F-5K drone at China Lake, 1957.

The Sidewinder incorporated a number of innovations over the independently developed World War II German Missile Enzian's "Madrid" IR range fuze that enabled it to be successful.[citation needed] The first innovation was to replace the "steering" mirror with a forward-facing mirror rotating around a shaft pointed out the front of the missile. The detector was mounted in front of the mirror. When the long axis of the mirror, the missile axis and the line of sight to the target all fell in the same plane, the reflected rays from the target reached the detector (provided the target was not very far off axis). Therefore, the angle of the mirror at the instant of detection estimated the direction of the target in the roll axis of the missile.

The yaw/pitch direction of the target depended on how far to the outer edge of the mirror the target was. If the target was further off axis, the rays reaching the detector would be reflected from the outer edge of the mirror. If the target was closer on axis, the rays would be reflected from closer to the centre of the mirror. Rotating on a fixed shaft, the mirror's linear speed was higher at the outer edge. Therefore if a target was further off-axis its "flash" in the detector occurred for a briefer time, or longer if it was closer to the center. The off-axis angle could then be estimated by the duration of the reflected pulse of infrared.

The Sidewinder also included a dramatically improved guidance algorithm. The Enzian attempted to fly directly at its target, feeding the direction of the telescope into the control system as it if were a joystick. This meant the missile always flew directly at its target, and under most conditions would end up behind it, "chasing" it down. This meant that the missile had to have enough of a speed advantage over its target that it did not run out of fuel during the interception.

The Sidewinder is not guided on the actual position recorded by the detector, but on the change in position since the last sighting. So if the target remained at 5 degrees left between two rotations of the mirror, the electronics would not output any signal to the control system. Consider a missile fired at right angles to its target; if the missile is flying at the same speed as the target it should "lead" it by 45 degrees, flying to an impact point far in front of where the target was when it was fired. If the missile is traveling four times the speed of the target, it should follow an angle about 11 degrees in front. In either case, the missile should keep that angle all the way to interception, which means that the angle that the target makes against the detector is constant. It was this constant angle that the Sidewinder attempted to maintain. This "proportional pursuit" system is very easy to implement, yet it offers high-performance lead calculation almost for free and can respond to changes in the target's flight path,[4] which is much more efficient and makes the missile "lead" the target.

However this system also requires the missile to have a fixed roll axis orientation. If the missile spins at all, the timing based on the speed of rotation of the mirror is no longer accurate. Correcting for this spin would normally require some sort of sensor to tell which way is "down" and then adding controls to correct it. Instead, small control surfaces were placed at the rear of the missile with spinning disks on their outer surface; these are known as rollerons. Airflow over the disk spins them to a high speed. If the missile starts to roll, the gyroscopic force of the disk drives the control surface into the airflow, cancelling the motion. Thus the Sidewinder team replaced a potentially complex control system with a simple mechanical solution.

gradenko_2000 posted:

How different were WW1 U-Boats compared to WW2 U-Boats? I keep hearing about how April 1917 was a really really bad month to be in the British Merchant Marine, though I can't quite imagine how advanced submarine technology would be by then.

quote:

On 22 September 1914, while patrolling the Broad Fourteens, a region of the southern North Sea, U-9 found a squadron of three obsolescent British Cressy-class armoured cruisers (HMS Aboukir, HMS Hogue, and HMS Cressy), (sardonically nicknamed the "Live Bait Squadron") which had been assigned to prevent German surface vessels from entering the eastern end of the English Channel. She fired all six of her torpedoes, reloading while submerged, and sank all three in less than an hour. 1459 British sailors died. It was one of the most notable submarine actions of all time. Members of the Admiralty who had considered submarines mere toys no longer expressed that opinion after this event.

gradenko_2000 posted:

How different were WW1 U-Boats compared to WW2 U-Boats? I keep hearing about how April 1917 was a really really bad month to be in the British Merchant Marine, though I can't quite imagine how advanced submarine technology would be by then.

Mr. Sunshine posted:

Dude, I'm in the Swedish National Guard, and we're this close to issuing orders over facebook!

Farecoal posted:

U-boats in WWI tended to use their deck guns over torpedoes, due to lack of planes trying to hunt them down. I believe the biggest U-boat ace of WWI almost exclusively used his deck gun.

A Fistful of Dicks posted:

This brings up another question: any of you bubbleheads know why subs don't use any anti-aircraft weaponry anymore? Seems like it'd be easy enough to fire of a SAM at a pursuing ASW aircraft.

A Fistful of Dicks posted:

I laughed way too hard at this...

I'm slowly but surely reading every single page of this thread, but in the meantime, I had another, somewhat topical hypothetical for the experts -- how would a war between India and Pakistan shake out now? At least to me, comparing the numbers on paper, it seems like Pakistan wouldn't really stand a chance against a numerically and technologically superior Indian force. But that's assuming a pitched conventional war, and we all know Pakistan likes to play dirty.

Vague question, but I'm open to any and all speculation. Thoughts?

Slo-Tek posted:

"America will save European culture from destruction....with what right?"

Slo-Tek posted:

I always terribly impressed with Kulturterror though, as propaganda imagery goes.

Slo-Tek posted:

Propaganda image.

Copernic posted:

Today I read this about the USS Gloucester:


How in the heck did they get a frigate from Lake Superior to the ocean?

Mister Adequate posted:

Though the St. Lawrence Locks weren't ready until 1959, there was already a pretty extensive system of canals and waterways up around the Great Lakes by the late 19th century. I presume they used those?

I've been trying to figure out who the hell that fourth guy on Trench_Rat's poster is and I'm not doing very well at all. The best guess I have is http://en.wikipedia.org/wiki/Otto_Liman_von_Sanders but why they would worry about a random advisor instead of an admiral or something is beyond me.

mllaneza posted:

He isn't a random advisor, he played a key part in bringing Turkey into the war, as well as commanding the defense at Gallipoli.

gradenko_2000 posted:

How different were WW1 U-Boats compared to WW2 U-Boats? I keep hearing about how April 1917 was a really really bad month to be in the British Merchant Marine, though I can't quite imagine how advanced submarine technology would be by then.

gradenko_2000 posted:

How / why did the Royal Navy blockade Germany so effectively in WW1? The Kaiserliche Marine was at least as large as the British fleet IIRC, so why not just sally forth and engage them?

On a related note, why was there starvation in WW1 Germany, but not in WW2 despite the similarly tight blockade? Advances in agricultural technology enabling self-sufficiency?

gradenko_2000 posted:

On a related note, why was there starvation in WW1 Germany, but not in WW2 despite the similarly tight blockade? Advances in agricultural technology enabling self-sufficiency?

Nenonen posted:

No, the Royal Navy was the largest navy in the world, no questions asked. In the largest engagement, the battle of Jutland, the Grand Fleet could muster 151 ships against 99 German ships. The German plan in Jutland was to hit the Grand Fleet so that a considerable proportion of it would be destroyed, and so maybe after a few battles like that the High Seas Fleet would really be superior in numbers and able to open the blockade. While the result was favourable to the Germans in sunken tonnage, it was far from being a major triumph. There was the risk of the Grand Fleet actually decimating the High Seas Fleet to the point where they couldn't even act as a fleet in being anymore.

Amused to Death posted:

If IIRC, wasn't the original plan for what became Jutland was the Germans tried to trick the British. They tried to make it look like it was only a small portion of the German Navy was going out, at which point Britain would send out its heavy/light cruisers to deal with it, they'd show up, and the entire German fleet would be there just waiting to decimate them, giving Germany a rather nice victory. Only Britain got word of the plan and the entire home fleet was there. Yes, no?

Nenonen posted:

No, the Royal Navy was the largest navy in the world, no questions asked. In the largest engagement, the battle of Jutland, the Grand Fleet could muster 151 ships against 99 German ships.

Retarded Pimp posted:

Another old man to die off before Gorbachev.

gradenko_2000 posted:

On a related note, why was there starvation in WW1 Germany, but not in WW2 despite the similarly tight blockade? Advances in agricultural technology enabling self-sufficiency?

mllaneza posted:

Ultimately the Germans were just jerking the British around, the RN wanted to smash the German fleet pretty badly and were going to come out every time they had a chance. They just weren't willing to take many (if any) risks of getting anything more than the battlecruiser force shot up to do it.

gradenko_2000 posted:

On a related note, why was there starvation in WW1 Germany, but not in WW2 despite the similarly tight blockade? Advances in agricultural technology enabling self-sufficiency?

Christoff posted:

Can you guys tell me aolbout drug use during any war? Just gnerally curious. I know the Nazis used meth but not much else. I'm sure less contemporary Militaries drank quite a bit around battles and he'll were maybe eating opium to numb pains.