Many of you have an account with Flickr, the image hosting site owned by Yahoo!
Did you know the US Army had a Flickr page? One of my consistent complaints about the Army’s public affairs efforts is that they have a ton of people taking great photos, but rarely do people find any good pictures. Yes, there are a ton of pictures of things less interesting, such as the Secretary of the Army watching the first day for cadets at West Point. But there are also some great photos of soldiers in their natural environment. You just have to dig a little to find them. Here’s a taste. Click on each to enlarge:
It’s a mashup of some footage from Iraq. Most of this looks to be from 2004 or early 2005. There’s some small arms, Bradleys, TOWs, Javelins, AT-4s and 500lb bombs. Interestingly, there’s a brief bit of Blackwater MD530 helicopters.
We’ve seen a similar video before, and couldn’t resist stealing this one from the Armorer over at The Castle. There is, not surprisingly, a good deal of NSFW language, so you might turn down the volume, or wait till you get home to watch.
What we see is a mortar team firing their 120mm mortar at Anti-Coalition Forces that are (presumably) attacking their Combat Outpost. Since the idea is to suppress the incoming fire, they are laying down both High Explosive and White Phosphorus rounds on the enemy. The HE of course blows up real good, and while the WP may cause casualties, the primary effect is the dense white smoke makes it hard for the enemy to aim their weapons.
Note the professionalism of the crew. Just as soon as the fight is over, they start clearing up the pit, counting their ammo, cleaning their tube, and generally getting everything set for another round. Impressive.
The Israelis have long sought to manufacture as much of their military hardware as possible at home.There are a couple good reasons for this. First, in the event of an arms embargo, they won’t find themselves without the weapons they need to fight. Having faced more than one embargo, they are somewhat wary of placing any faith in anybody outside Israel. Second, as an export industry, it can be very profitable, once they have an established production base. There are more than a couple countries that have no great love for Israel but have ended up buying military hardware from them.
One area the Israelis really wanted to establish some independence in was making tanks. A modern tank takes a lot more work to make than you might think. The armor itself is difficult to produce. You also need powerful engines, the delicate machinery to operate the turret, the precision milling to make the main gun, the specialized electronics and optics for the fire control system and an industry to make the ammunition.
After the 1973 Yom Kippur War, Israel got serious about manufacturing their own tank. And based on the heavy casualties in tank crews during that war, one of the objectives was to make crew survivability a priority (the US Army’s design of the M-1 tank was also heavily influenced by the same factors).
The result of the development was the Merkava tank. The Merkava was a little unusual in several ways. Unlike just about every other main battle tank in the world, the Merkava had its engine mounted in the front, pushing the turret towards the rear. This provided an extra degree of protection in that if a round penetrated the front armor, it would still have to go through the engine to get to the crew compartment. And because the crew compartment was at the rear of the vehicle, you could put a small entry to the vehicle in the back. By removing some of the ammo racks, you could provide space for a couple infantrymen or extra radios and operators for a unit commander or even put in medics and litters to use the vehicle as an ambulance. Finally, the wedge shaped turret was designed to cause most shells striking it to ricochet rather than penetrate.
Over the years, the Merkava has been developed in four main versions. Most of the early versions are being withdrawn from service. Some thought was given to converting them to armored personnel carriers, but as of 2008 the decision was made to build new APCs based on the Merkava 4 design.
Back in Breaking the Code, I mentioned one of the Infantry Military Occupational Specialties was Indirect Fire Infantryman. Translated to English, this means a mortarman. Mortars are the infantry and armor commander’s “hip pocket” artillery. Each infantry and armor battalion has a platoon of mortars and most infantry companies have a mortar section. Supporting fires are just a quick call away.
A mortar is basically a smoothbore tube with a firing pin at the bottom. The mortar round is stabilized in flight by fins at its bottom. The round is fired by simply dropping it down the tube. The range can be increased or decreased by adding or subtracting powder charges (called “cheeses”) from around the base of the projectile.
Our Army uses three different types of mortars, the 60mm:
The 81mm:
The 120mm:
Mortars can fire high explosive rounds to kill or supress enemy troops. They can also fire smoke to provide screens for friendly troops or mark enemy positions.
Here’s a quick youtube of a mortar platoon doing some live-fire. This was taken at the Pohakaloa Training Area on the Big Island of Hawaii. It is not exactly the garden spot of the world.
We’ve talked a bit about the M-1 Abrams tank before, and in some of our posts, we’ve discussed gunnery qualifications for Bradley crews.
Tank gunnery qualification is almost identical in structure to Bradley qualification. This video shows some crews firing the day qualification in Germany. After they finish this, they’ll go back and do it again at night.
During the actaul qualification, each run is videotaped, and the radio and intercom are recorded to assist in grading the crews. Crews are scored on accuracy, speed, and technique-such as issuing the proper fire commands and proper driving technique.
The targets are mostly plywood, designed to fall after being hit. Since the rounds only leave a small hole, they can be used again and again. Many times, when it looks like a round has hit behind the target, it really has gone through the target, and is scored as a hit. Just look for the target falling.
Reader Craig sent along a link to a video of testing the XM1028 round for the Abrams tank. I’m not sure if this is in service yet. Basically, it is a giant shotgun shell for the M-1. Since neither the HEAT or Sabot rounds do much good against infantry in the open, this is the solution.
We’ve covered Explosively Formed Projectiles here. EFPs however, are a relatively small slice of the anti-armor pie. Far more common are the HEAT round and the Sabot.
HEAT stands for High Explosive Anti Tank. HEAT rounds are also known as “shaped charges”. Just using high explosives doesn’t do much to penetrate armor. By shaping the explosives in an inverted cone, and usually lining this cone with a copper sheath, the explosive effect can be channeled into a very small spot on the target. This superheated jet of fire and molten copper then “burns” through the armor. While this produces only a small hole in the armor, the fire and copper tend to ignite anything inside the vehicle. Military vehicles are stuffed with flammables (people count as flammables) or explosives, so any penetration of the armor can have devastating consequences.
Ballistic cap
Chamber reduction – to improve the penetrating beam’s characteristic
Inverse-cone hollow room, covered with thin metal layer, which the penetrator is built from
Fuse
Explosive combat charge
Piezoelectric bounce-on fuze initializer
The rule of thumb is that a shaped charge can penetrate six times its own diameter. A 4″ warhead, then would notionally penetrate two feet of armor.* This means that relatively small warhead can provide quite a bit of punch. The first common use of shaped charge warheads was in WWII by the “Bazooka”. To this day, we still see small, man portable rocket launchers all over the battlefield. Common examples are the Soviet designed RPG-7 and the US AT-4. Whereas the RPG-7 is a reloadable launcher, the AT-4 is a disposable, one shot weapon.
Anti-tank missiles also almost always have a HEAT warhead. Since the speed of the warhead on impact makes no difference in penetration, relatively slow (hence lightweight) missiles can be used. In US service, both the TOW missile and the Hellfire have HEAT warheads.
But missiles and rockets aren’t the only place HEAT rounds are used. Tanks can also fire HEAT rounds. In fact, one of the reasons why the M-1A1 Abrams tank has a smoothbore main gun is that HEAT rounds work better when they aren’t spinning rapidly. Instead, they use pop-out fins to stabilize the shell. The original 120mm M830 HEAT round looked like a coffee can with a probe attached.
The probe is designed to detonate the warhead at a set distance from the target, giving the hot jet of gasses space to fully form. To close in, and the jet doesn’t form. Too far out, and the jet loses it’s focus.
In the past few years, the M830 was replaced by the M830A1, with a slightly smaller warhead, but with a proximity fuse to allow it to defeat helicopters and other soft targets.
While HEAT rounds are simple and cheap, and fairly effective, there are countermeasures. A simple, low cost countermeasure is the cage, seen here on a Stryker Infantry Carrier Vehicle.
The cage either prevents the fuse from detonating the warhead, or causes the warhead to detonate too far out to be effective. Explosive reactive tiles can be bolted onto the outside of vehicles as well. These explode when hit by a HEAT round and the explosion disrupts the jet of the warhead.Tanks like the Abrams use composite armor with layers of steel and ceramic to defeat HEAT rounds.
Sabot rounds overcome these weaknesses. Sabots, also know as kinetic energy penetrators, use sheer momentum to penetrate armor. In the early days of armored warfare, AP (armor piercing) rounds were solid shot or had a small bursting charge. Basically, they were just big, hardened steel bullets. But as armor grew thicker, AP rounds lost their ability to penetrate armor. The solution was the long rod penetrator. By making the solid shot thinner but longer, the projectile would maintain the same weight while focusing its impact on a smaller area. This improved penetration. To make this thin, dart shaped projectile fit into a cannon, the dart was wrapped in a “sabot” or shoe. These sabots would fall off as the dart left the barrel.
There are no explosive in the dart. Just the energy transferred from the impact will generate enormous amounts of heat as it slices through the targets armor. Also, chips of the dart and the targets own armor are superheated and sprayed inside the target vehicle, setting afire fuel and ammo. This quickly leads to the catastrophic destruction of the target.
The drawback of a sabot round is that it takes a very big gun (like a 105mm or 120mm) to generate the velocity needed to penetrate armor. This means a big vehicle to mount the gun. The trade off here is that while a heat round can be transported easily, tank takes a lot more logistical support.
Also, while sabot rounds have great penetration, they don’t do a lot of damage outside the immediate area of impact. Sabots are of little use in urban combat such as Iraq. Tank crews there are far more likely to use HEAT rounds to engage the enemy.
*When we talk about armor penetration, we are measuring against a benchmark of Rolled Homogeneous Armor or RHA. Different armors will have different protections. Two feet of aluminum won’t provide as much protection as two feet of RHA steel.
I wrote earlier about bringing enough gun to the fight, but not too much. A prime example of this was the M-1 Abrams tank.
When this tank debuted, people were aghast at the cost. What they didn’t realize was it was acutally the result of an extreme cost cutting program. For 20 years, the Army had been cooperating with Germany to develop a sucessor to the M-60 series of tanks, but each iteration had become too complex and too costly. The Army finally decided that they would develop a tank using technology shared with the Germans rather than develop a tank to be used by both countries.
One of the sticking points was the main gun. The standard US tank gun was the 105mm M68. The Army thought this was sufficient to defeat current and projected Soviet armor (and were pretty much right).
The Germans had developed the excellent 120mm smoothbore, and wanted both countries tanks to use it. Our Army resisted for a couple of reasons. The biggest was cost. The new gun would have to be license produced here, with associated setup costs. Even more expensive would be providing stocks of ammunition for the gun. The Army had a huge stockpile of 105mm ammunition already. Buying an entirely new stockpile in the tight budgets of the 1970s wasn’t an attractive option.
In the end, the 105mm won-sort of. The decision was to place the M-1 into production with the 105mm, but make provision to add the 120mm in the future. As it turned out, for various reasons, this was a lot harder than anyone expected. Still, partly as a sop to our German allies, and partly over concern about the ability of the 105mm to defeat future Soviet armor, the 120mm was adopted for the M1A1 that entered service in 1988.
One disadvantage of the 120mm was a reduced ammo load. An M-1 with the 105mm carries 55 main gun rounds. An M-1A1 carries 40. As it turns out, however, few tanks will shoot their entire basic load in a single battle. In fact, not a single tank in Desert Storm fired its entire basic load.
Tankers, ever wonder why the coax on your tank has that massive 4000 round load? Because that’s where the designers originally wanted to put the 25mm M242. The only reason it didn’t make it into the final design was cost. Leaving the 25mm out saved about $100,000 just for the gun, and made the fire-control system simpler, and hence cheaper.
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Posted by xbradtc 
Posted by xbradtc 
Posted by xbradtc 
