That date marks one of the most creative periods of conceptual design for any fighter aircraft

Wednesday, October 5th, 2022

When the F-22 design team struggled to meet its weight and unit-cost goals, it decided to step back and open up the design to more fundamental changes:

“After a bloody debate, we agreed to trash the current design and start over,” says Mullin. “Over that weekend, we brought in a new director of design engineering, Dick Cantrell, flew in people, and started a ninety-day fire drill. Work started on Monday 13 July. That date marks one of the most creative periods of conceptual design for any fighter aircraft. We looked at different inlets, different wings, and different tail combinations. One configuration had two big butterfly tails and looked somewhat like the F-117, though people did not know that since the F-117 was still highly classified. The configuration search was wide open, but the biggest single change that resulted from it was to go with diamond-shaped wings.”

The concentrated configuration search began with a slew of possible designs. The search complicates the numbering scheme considerably, as diamond wings, twin tails (two tails instead of four), various inlet shapes, and various forebody shapes were all considered and reconsidered simultaneously in the summer of 1987.

[…]

“The fundamental reason for going to a diamond wing was that it provided the lightest configuration and gave us the best structural efficiency and all the control power we needed for maneuvering,” Mullin explains. “The biggest consideration was its light weight. Weight drove the decision.”

“A diamond wing has more square feet of surface area, but is more structurally efficient,” adds Renshaw. “The longer root chord provides a more distributed load path through the fuselage. Multiple bulkheads carry the bending loads. The design provides more opportunity to space the bulkheads around the internal equipment. It also provides more fuel volume.”

“The structural engineers wanted a diamond wing because it provides a larger root chord, which carries bending moments better,” Hardy notes. “The aerodynamicists wanted a trapezoidal wing because it provides more aspect ratio, which is good for aerodynamics. Dick Heppe, the president of Lockheed California Company, made the final decision, and he was right. The aerodynamics were not all that different, but the structure and weights were significantly better. So we went to a diamond shape. The big root chord, though, moved the tails back. Eventually we even had to notch the wing for the front of the tails. If the tails moved farther back, they would fall off the airplane.”

Once the wings were set with Configuration 614, subsequent configurations dealt with the tail arrangement. “We spent a lot of wind tunnel time looking at the tails,” recalls Lou Bangert, the chief engineer for engine integration from Lockheed. “From late 1987 to early 1988, we were engaged in what we called ‘the great tail chase.’ We knew we would have four tails, but where they would go was a big deal. A small change in location often made a huge difference. We had to look at performance effects, stealth effects, stability and control, and drag at the same time. The tail arrangement and aft end design were important design considerations for all of these effects.”

Wind tunnel results showed an ultra-sensitive relationship between the placement of the vertical tails and the design of the forward fuselage. The interactions could not be predicted accurately by analysis or by computational fluid dynamics. The airflow over the forebody at certain angles of attack affects the control power exerted by the twin rudders on the vertical tails. Getting the airflow right was critical.

The cant and sweep angles of the vertical tails could not be altered too much because such changes increased radar signature. In finding a suitable arrangement, the control system designers were constrained by the radar signature requirements to moving the tail locations laterally or longitudinally and to shrinking or enlarging them while holding the shape essentially constant. By the end of the dem/val phase, the team had accumulated around 20,000 hours in the wind tunnel. A lot of this time was devoted to tail placement studies.

Everything wants to be at the center of gravity

Monday, October 3rd, 2022

The basic challenge of designing the F-22 was to pack stealth, supercruise, highly integrated avionics, and agility into an airplane with an operating range that bettered the F-15, the aircraft it was to replace:

“One problem we typically face when trying to stuff everything inside an airplane is that everything wants to be at the center of gravity,” Hardy explains. “The weapons want to be at the center of gravity so that when they drop, the airplane doesn’t change its stability modes. The main landing gear wants to be right behind the center of gravity so the airplane doesn’t fall on its tail and so it can rotate fairly easily for takeoffs. The fuel volume wants to be at the center of gravity, so the center of gravity doesn’t shift as the fuel tanks empty. Having the center of gravity move as fuel burns reduces stability and control. We also had to hide the engine face for stealth reasons. So, these huge ducts had to run right through the middle of real estate that we wanted to use for everything else. The design complexities result in specialized groups of engineers arguing for space in the airplane. That was the basic situation from 1986 through 1988.”

Corbett regarded total command of the sea with skepticism

Sunday, October 2nd, 2022

Ukraine’s success in contesting the skies turns the West’s airpower paradigm on its head, because it offers an alternative vision for pursuing airspace denial over air superiority:

In rethinking America’s approach to airpower, pundits should look to Mahan’s contemporary, the British naval theorist Sir Julian Corbett. Corbett regarded total command of the sea with skepticism, arguing the “most common situation in naval warfare is that neither side has the command.” He favored a relative, rather than an absolute, interpretation of command of the sea, calling for a “working command,” delimited in time or space — “sea control” in today’s parlance. Similarly, Douhet’s absolute rule of the skies may be desirable, but air forces may get by with more limited control of the airspace, or temporary and localized air superiority.

For Corbett, the corollary of sea control is sea denial. If a navy is not strong enough to gain command of the sea, he argued, it could still attempt to limit or deny the other side ability to make use of the sea. He referred to this concept as “disputing command,” and offered two main methods: a “fleet in being” and “minor counterattacks.” He envisioned an active defense, in which a smaller navy could avoid battle but still remain threatening as a “fleet in being” by staying active and mobile. “The idea,” he explained,” was “to dispute control by harassing operations, to exercise control at any place or at any [opportune] moment … and to prevent the enemy from exercising control in spite of his superiority by continually occupying his attention.” Additionally, an inferior navy could conduct minor counterattacks, or hit-and-run strikes, to try to take undefended ships out of action.

Corbett’s strategy of denial in the naval realm is pertinent to the air domain as well. Ukraine has used mobility and dispersion to maintain its air defenses as a “force in being.” Operating a mix of Cold-War era, Soviet-made mobile surface-to-air missile systems Ukrainian defenders on the ground have kept Russian aircraft at bay and under threat. To do so they have used the long range S-300 family, medium range SA-11s, and short range SA-8 Gecko systems. Exploiting dispersion and mobility, as Corbett advised, Ukrainian air defenders have used “shoot and scoot” tactics, firing their missiles and quickly moving away from the launch site. “The Ukrainians continue to be very nimble in how they use both short and long-range air defense,” a senior Pentagon official concluded. “And they have proven very effective at moving those assets around to help protect them.”

Mounted on tracked vehicles, Ukraine’s surface-to-air missile systems are fleeting targets. Given the danger of flying over Ukraine, Russia relies largely on standoff sensors to find radar targets, lengthening the time required to engage Ukraine’s mobile systems. After firing, the defender can turn off the radar, pack up and drive away to hide in the ground clutter — forests, buildings, etc. During the Gulf War in 1991, the U.S.-led coalition hunted Iraq’s truck-mounted Scud missiles, but even with the advantage of air superiority, it still failed to achieve a single confirmed kill. In the skies over Ukraine, Russian aircraft are not only the hunter but also the hunted, further complicating the task of finding and destroying them.

As a result, there is a deadly “cat-and-mouse” game between Russian aircraft and Ukrainian air defenses. The Oryx open-source intelligence site reports that, since the start of the war, 96 Russian aircraft have been destroyed, including at least nine Sukhoi Su-34 and one Su-35 — equivalents to the American F-15. Ukraine started the war with a total of 250 S-300 launchers, but 11 weeks later, the Russians have only managed to knock out 24 of them, at least so far as Oryx has confirmed with photos and videos. Given how Ukrainian officials carefully manage information about their losses, caution is needed in drawing conclusions from our limited information about them. Still these figures suggest that the Russians are only able to attrite a small portion of the threat, and, compared to radar and battery command vehicles, the less important part at that. The best evidence may be Russian behavior itself. As a senior Pentagon official argued, “And one of the reasons we know … [Ukraine’s air defenses are] working is because we continue to see the Russians wary of venturing into Ukrainian air space at all and if they do, they don’t stay long … And I think … that speaks volumes …”

Thirty-one percent of the gun owners said they had used a firearm to defend themselves or their property

Tuesday, September 20th, 2022

The largest and most comprehensive survey of American gun owners ever conducted, based on a representative sample of about 54,000 adults, 16,708 of whom were gun owners, suggests that Americans use firearms in self-defense about 1.7 million times a year:

The overall adult gun ownership rate estimated by the survey, 32 percent, is consistent with recent research by Gallup and the Pew Research Center. So is the finding that the rate varies across racial and ethnic groups: It was about 25 percent among African Americans, 28 percent among Hispanics, 19 percent among Asians, and 34 percent among whites. Men accounted for about 58 percent of gun owners.

Because of the unusually large sample, the survey was able to produce state-specific estimates that are apt to be more reliable than previous estimates. Gun ownership rates ranged from about 16 percent in Massachusetts and Hawaii to more than 50 percent in Idaho and West Virginia.

The survey results indicate that Americans own some 415 million firearms, including 171 million handguns, 146 million rifles, and 98 million shotguns. About 30 percent of respondents reported that they had ever owned AR-15s or similar rifles, which are classified as “assault weapons” under several state laws and a proposed federal ban. Such legislation also commonly imposes a limit on magazine capacity, typically 10 rounds. Nearly half of the respondents (48 percent) said they had ever owned magazines that can hold more than 10 rounds.

Those results underline the practical challenges that legislators face when they try to eliminate “assault weapons” or “large capacity” magazines. The survey suggests that up to 44 million AR-15-style rifles and up to 542 million magazines with capacities exceeding 10 rounds are already in circulation.

Those are upper-bound estimates, since people who reported that they ever owned such rifles or magazines may have subsequently sold them. But even allowing for some double counting, these numbers suggest how unrealistic it is to suppose that bans will have a significant impact on criminal use of the targeted products. At the same time, widespread ownership of those products by law-abiding Americans makes the bans vulnerable to constitutional challenges.

Two-thirds of the respondents who reported owning AR-15-style rifles said they used them for recreational target shooting, while half mentioned hunting and a third mentioned competitive shooting. Sixty-two percent said they used such rifles for home defense, and 35 percent cited defense outside the home. Yet politicians who want to ban these rifles insist they are good for nothing but mass murder.

[…]

Thirty-one percent of the gun owners said they had used a firearm to defend themselves or their property, often on multiple occasions. As in previous research, the vast majority of such incidents (82 percent) did not involve firing a gun, let alone injuring or killing an attacker. In more than four-fifths of the cases, respondents reported that brandishing or mentioning a firearm was enough to eliminate the threat.

That reality helps explain the wide divergence in estimates of defensive gun uses.

[…]

About half of the defensive gun uses identified by the survey involved more than one assailant. Four-fifths occurred inside the gun owner’s home or on his property, while 9 percent happened in a public place and 3 percent happened at work. The most commonly used firearms were handguns (66 percent), followed by shotguns (21 percent) and rifles (13 percent).

Smart bombs payout immediately by requiring a fraction of the ordnance

Thursday, September 1st, 2022

Austin Vernon discusses the economic logic of smart bombs:

US smart bombs like the GPS-guided JDAM and the laser-guided Paveway cost somewhere between $10,000 and $30,000 to manufacture. They are nearly 100% accurate in hitting a target, while unguided bombs are stuck with single-digit accuracy numbers. Unguided dumb bombs cost $2000-$3000 per bomb. Smart bombs payout immediately by requiring a fraction of the ordnance.

It is worse than that, though. A fighter jet like the US Navy’s F-18 costs over $10,000 an hour to operate, not including tankers. A B-52 bomber costs $70,000 an hour. Attacking targets using dumb bombs requires ten times the sorties at a significant cost premium and exposes planes and pilots to more risk.

[…]

Modern smart bombs fired by aircraft can provide support and screening for fast advancing mechanized columns instead of artillery. In the early Afghanistan conflict in 2001, the US deployed zero artillery because of its weight and logistics challenges. Combat aircraft were able to cover US ground forces against light Taliban forces.

In the 2003 invasion of Iraq, armor columns brought much less artillery than in 1991. Aircraft took over the strategic mission, leaving counter-battery fire and all-weather close fire support to artillery forces.

[…]

Smart weapons also have standoff capability. An unpowered JDAM bomb can glide over 25 km.

[…]

Drones are a continuation of the precision-guided munition paradigm. Smart bombs can make a plane 20x more effective. Drones are force multipliers across the board. The Army and Air Force have been drone leaders but need to continue to invest in drones across the spectrum. They need large, expensive drones that can operate far from bases and inexpensive micro-drones that can disrupt enemy formations or intercept enemy micro-drones. Modern warfare is an o-ring industry because enemies exploit gaps relentlessly.

Each Starship launch has the same payload as three B-52s

Wednesday, August 31st, 2022

Recent talk about hypersonic missiles got me wondering whether SpaceX’s reusable rockets would lend themselves to this role. Austin Vernon suggests that SpaceX’s Starship is America’s Secret Weapon:

B-52s flying from Barksdale AFB to complete a mission in East Asia incur a marginal cost of $50/kg to deliver bombs. Starship’s cost is cheaper and can put weapons on target in less than thirty minutes. Each Starship launch has the same payload as three B-52s.

[…]

The supply line would be a natural gas pipeline and a rail line providing fuel and projectiles to a domestic launchpad instead of ships crossing oceans.

I hadn’t considered this though:

Orbital weapons still need intelligence to tell them where to go. Starship’s sister system, StarLink, provides an answer. StarLink is a constellation of thousands of small Low Earth Orbit satellites that gives customers low latency broadband internet. It uses sophisticated phased-array radios that allow ground terminals to track satellites traveling thousands of miles per hour.

As Casey Handmer points out, StarLink can use its radios to do high fidelity synthetic aperture radar (SAR). SAR is already one of the primary ways militaries find enemy ships, and researchers have used it to track planes. It could also see ground vehicles.

While the US already has satellites capable of doing this, they are expensive and limited in number. Individual StarLink satellites cost a few hundred thousand apiece to build and launch on Starship. One of the first things China would do in war is shoot down our military satellites with anti-satellite missiles. That is a problem with bespoke satellites but not with Starlink. Anti-Satellite missiles cost tens of millions of dollars. Each Starship launch could drop off hundred of StarLink satellites. The Chinese would have to expend incredible resources to keep StarLink offline.

A satellite constellation provides other bonuses. Our GPS satellites are both hard to replace and sensitive to jamming. StarLink can provide GPS coordinates (with a few meters less accuracy), and its phased array radios make it difficult to jam.

The upshot is StarLink gives the US survivable sensing, communication, and navigation capabilities.

The military can’t afford iPhone-level software

Tuesday, August 30th, 2022

As consumers, we are spoiled by how easy our phones are to use, Austin Vernon notes, and critics expect the military to have software as capable as our phones:

If you examine the numbers, it quickly becomes apparent that the military can’t afford iPhone-level software. Apple, Google, Microsoft, and Facebook had combined operating expenses of over $600 billion in 2021. The military’s total budget is around $750 billion.

The mass of all the physical products these companies sell is probably less than one Ford-class aircraft carrier, and the number of SKUs is relatively limited. And remember, a defining feature of the software business is that marginal cost is near zero. It costs about the same to design high-quality software for 100 F-35s as for 200 million copies of the plane.

The Rotating Detonation Engine is an extension of the Pulse Detonation Engine, which is an extension of The Pulse Jet Engine

Wednesday, August 24th, 2022

The concept behind rotation detonation engines dates back to the 1950s:

In the United States, Arthur Nicholls, a professor emeritus of aerospace engineering at the University of Michigan, was among the first to attempt to develop a working RDE design.

In some ways, a Rotating Detonation Engine is an extension of the concept behind pulse detonation engines (PDEs), which are, in themselves, an extension of pulsejets. That might seem confusing (and maybe it is), but we’ll break it down.

Pulsejet engines work by mixing air and fuel within a combustion chamber and then igniting the mixture to fire out of a nozzle in rapid pulses, rather than under consistent combustion like you might find in other jet engines.

In pulsejet engines, as in nearly all combustion engines, igniting and burning the air/fuel mixture is called deflagration, which basically means heating a substance until it burns away rapidly, but at subsonic speeds.

A pulse detonation engine works similarly, but instead of leveraging deflagration, it uses detonation. At a fundamental level, detonation is a lot like it sounds: an explosion.

While deflagration speaks to the ignition and subsonic burning of the air/fuel mixture, detonation is supersonic. When the air and fuel are mixed in a pulse detonation engine, they’re ignited, creating deflagration like in any other combustion engine. However, within the longer exhaust tube, a powerful pressure wave compresses the unburnt fuel ahead of the ignition, heating it above ignition temperature in what is known as the deflagration-to-detonation transition (DDT). In other words, rather than burning through the fuel rapidly, it detonates, producing more thrust from the same amount of fuel; an explosion, rather than a rapid burn.

The detonations still occur in pulses, like in a pulsejet, but a pulse detonation engine is capable of propelling a vehicle to higher speeds, believed to be around Mach 5. Because detonation releases more energy than deflagration, detonation engines are more efficient — producing more thrust with less fuel, allowing for lighter loads and greater ranges.

The detonation shockwave travels significantly faster than the deflagration wave leveraged by today’s jet engines, Trimble explained: up to 2,000 meters per second (4,475 miles per hour) compared to 10 meters per second from deflagration.

[...]

A rotating detonation engine takes this concept to the next level. Rather than having the detonation wave travel out the back of the aircraft as propulsion, it travels around a circular channel within the engine itself.

Fuel and oxidizers are added to the channel through small holes, which are then struck and ignited by the rapidly circling detonation wave. The result is an engine that produces continuous thrust, rather than thrust in pulses, while still offering the improved efficiency of a detonation engine. Many rotation detonation engines have more than one detonation wave circling the chamber at the same time.

As Trimble explains, RDEs see pressure increase during detonation, whereas traditional jet engines see a total pressure loss during combustion, offering greater efficiency. In fact, rotation detonation engines are even more efficient than pulse detonation engines, which need the combustion chamber to be purged and refilled for each pulse.

[...]

According to the Air Force Research Lab, RDE technology could make high-speed weapons much more affordable, which is of particular import following a recent Defense Department analysis that indicated the hypersonic (Mach 5+) weapons in development for the Air Force may cost as much as $106 million each.

A 9V battery feeding a capacitor provided the energy to ignite the new type of primer

Friday, July 22nd, 2022

The recent unpleasantness in Japan piqued my interest in DIY firearms and electronic ignition, which led me to the Remington Model 700 EtronX, which was introduced in 2000 and discontinued in 2003. Ian of Forgotten Weapons explains:

It consisted of a standard Remington 700 bolt action rifle, with the trigger and firing mechanisms replaced by electric versions. The firing pin itself became an insulated electrode, the trigger operated an electronic switch instead of a mechanical sear, and a 9V battery feeding a capacitor provided the energy to ignite the new type of primer — basically a resistor that would generate heat to ignite a charge of smokeless powder.

[…]

Unfortunately, the only practical advantage to the electronic workings was a reduction in lock time of the action (the delay from trigger press to cartridge ignition). They did in fact achieve a virtual elimination of lock time, but this was not a problem that needed to be addressed for the general sporting rifle market.

Now, if they introduced a gun that didn’t need conventional primers today, they might have some success.

One hobbyist found it surprisingly hard to ignite gunpowder:

Experiments performed a few years ago and shown on the web page here found that weak sparks, such as from static electricity, are incapable of igniting black powder. Since I wanted to use smokeless powder in the rifle, and since it has a much higher ignition point than the black powder shown here, my first attempts used sparks from a stun-gun to see if they could ignite the powder.

The stun gun shown here is advertised as producing a 100,000 volt spark. The sparks were certainly loud and impressive, and they easily burned tiny holes through a piece of paper placed between the electrodes, but would they ignite powder?

Hundreds of sparks were struck into a pile of Hodgdon’s Tite-Group smokeless powder (left) and Swiss black powder (right) with absolutely no effect except for bouncing the grains around. The sparks were striking the grains, and you can see flashes when the spark hits the surface of the granules, but never once would the powder ignite!

The photo below shows a spark from the stun gun going completely through a line of black powder stuck to a piece of masking tape, and although hundreds of grains were simultaneously hit, nothing happened.

[…]

About this time I was ready to give up, but after a few days of reflection, I thought I knew what was happening. The spark in the chamber was clearly extraordinarily hot and was vigorous enough to blow the tamper out of the chamber, which meant that the air in the chamber had to be heated to a high temperature. But why didn’t the powder ignite? I believed the reason was the extremely brief duration of the spark; in trying to capture it on a video, it was so brief that it took many tries to accidentally capture a video frame on a camera running 30 frames/second. My guess is that it lasted only a few micro seconds, and thus, no matter how hot it was, it couldn’t transfer enough heat into the powder granules during this brief time period for them to ignite. Therefore, slowing down the spark, even if it meant reducing its intensity, might be enough to do the job.

To slow down the spark, I simply added a resistor in series with the capacitor so the current was limited to about two amperes — which is still a lot of current going through a spark. As you can see from the image, the spark was much brighter than from the spark coil alone, but was very much less intense than without the resistor. However, it seemed to last a bit longer — about 2000 micro seconds, so that elongation might do the trick.

I added some smokeless powder (this time without a tamper) and sparked it. It worked! Not only did it work for the Tite Group smokeless powder, but for all others I tried, and all ignitions were instantaneous.

China has a long and effective history of using massed small craft to rebuff stronger rivals

Monday, July 18th, 2022

China’s gray-zone fleet is hard to handle:

China has a long and effective history of using massed small craft to rebuff stronger rivals. The Communist regime employed massed small craft to project sovereignty as early as 1966, when eleven steel-hulled Chinese trawlers joined together to chase USS Pueblo’s (AGER-2) sister ship, the surveillance-oriented USS Banner (AGER-1), out of the East China Sea. For China, swarming is a long-standing, deeply rooted military tactic.

Coast Guards and Navies throughout the Pacific have long-struggled with strategies to manage China’s preference for fielding numerous but low-tech maritime vessels. Up till now, only aircraft and surface presence, in the form of massed, highly capable gunboats, have been effective against China’s militarized gray zone fleet.

Over the past few years, minor successes in rebuffing China’s coercive fleets has sparked something of a low-tech arms race. As Pacific states slowly up-armed their defensive resources, increasing presence in both ship numbers and in individual ship tonnage, China has, in turn, quietly “super-sized” their low-tech armada, making their ships too big and fast for other countries to confront.

While low-key, the growth of China’s low-tech fleet has been dramatic. China’s Coast Guard cutter fleet is expanding in number and size, and now boasts over 130 ships of over 1,000 tons. Today, the largest Chinese cutters are able to shoulder aside anything short of an Arleigh Burke destroyer. And while still lightly-armed, China’s Coast Guard fleet has gotten better basic weapons as well. Rapid-fire guns and man-portable anti-aircraft missiles make approach by rotary wing aircraft increasingly perilous, complicating efforts to target ships with laser-guided munitions, weapons the U.S. has used to clear the seas of lightly-armed adversaries in the past.

But now, America’s QUICKSINK makes even the queens of the Chinese Coast Guard, the massive 12,000-ton Zhaotou Class Coast Guard cutters, vulnerable.

Quicksink provides a low-cost anti-ship capability by using a modified 2,000-pound class GBU-31 Joint Direct Attack Munition, or JDAM, with a new Weapon Open Systems Architecture, or WOSA, seeker.

Craft-produced firearm used to assassinate Shinzo Abe

Saturday, July 9th, 2022

The assassin who shot and killed former Prime Minister Abe likely used a craft-produced, muzzle-loading, double-barrel smoothbore weapon, using separate-loading ammunition which was initiated by an electric firing mechanism:

The barrels of the firearm appear to be constructed from two metal tubes (most likely commercially available pipe) that were sealed at the rear using screw-on endcaps. The barrels are attached to a piece of wood using black adhesive tape (probably electrical tape). A pistol grip is attached to the wooden body of the weapon. There may also be other fasteners which are not visible underneath the tape. Based on the general arrangement of the firearm, its design, and its apparent build quality, it is likely that the weapon was a smoothbore design — that is, the barrels were not rifled — and the ammunition was fired under relatively low pressures. The significant plumes of smoke generated when the weapon was fired indicate that it does not make use of commercial small arms ammunition propellant (‘smokeless powder’), and may instead use blackpowder or an alternative propellant. This makes the use of ‘separate-loading’ ammunition (i.e., propellant and projectile loaded separately into the weapon) more likely, as well as increasing the likelihood that the weapon was a muzzle-loading design — that is, loaded from the bore (‘front’ of the barrel), rather than the breech (‘rear’ of the barrel) of the firearm.

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A popular design for simple craft-produced shotguns is the so-called ‘slam-fire shotgun’. Several observers have suggested this is the type of weapon used in the attack against Abe. However, these designs rely on conventional, impact-sensitive primers as found in modern small arms ammunition. The firing signature of the weapon suggests the use of an alternative propellant composition, as noted, and thus a slam-fire design is unlikely. The assailant likely used similar iron plumbing pipes and endcaps similar to those used on craft-produced firearms chambering conventional shotgun ammunition. However, the weapon appears to use an electric firing mechanism. Images of the firearm show that an electrical wire passes through each endcap. The trigger mechanism seems to connect these wires to two battery packs. There are several different designs of electrical firing mechanism. There have been, for example, significant developments focused on electric primers within the community of 3D-printed firearms designers. Probably the most prominent electric firing mechanism for 3D-printed firearms has been developed by the user ‘@SuckBoyTony1’. This mechanism uses an 80 kV High Voltage Pulse Generator that converts 6–12 V (the electric potential typically provided by battery packs such as that seen with the assailant’s weapon) into 80 kV. This high voltage creates a hot plasma arc between two conductive contacts that can be used to ignite flammable materials — such as propane in a grill or blackpowder in a firearm. In @SuckBoyTony1’s design, the contacts are held in place by a 3D-printed housing (see Figure 4). This igniter design can repeatedly create the hot plasma arc as long as the batteries can provide enough power and the contact rods are not worn off.

[…]

A few hours after the shooting, Japanese police raided the assailant’s home. Following this, images of three further firearms with similar physical features emerged. One example featured five barrels, arranged in two rows (see Figure 7); the second example featured six barrels, arranged in two rows (Figure 8); and the third featured nine barrels, arranged in three rows (Figure 9). Both are wrapped in a similar black adhesive tape, and both appear to use electrical firing systems similar to that seen on the weapon used in the shooting. Improved concealability is the most likely reason for the assailant’s selection of the double-barrelled example, although reliability may also have been a factor.

[…]

Japan has long implemented strict arms control laws. Under current Japanese law, civilians are barred from owning handguns and rifles under most circumstances, and shotguns are tightly regulated. The most recent estimate (2019) suggests that there are only 132,127 shotguns in private hands. Japan’s per capita rate of firearms ownership is the lowest amongst G7 countries, estimated at just 0.3 firearms per 100 people in 2018. As such—and in common with most craft-produced firearms users around the world—Abe’s assassin most likely made his own firearm because he could not gain access to an industrially produced example. Ammunition is also tightly regulated in Japan. Indeed, the strict control of conventional cartridges in Japan makes it more likely that the assailant selected separate-loading ammunition to avoid these legal restrictions. Reports that explosives were located at the assailant’s home may also indicate a store of loose propellant and/or a capability to produce propellant.

No Western artillery system is as capable and none apparently has the accuracy offered by GIS Arta

Tuesday, July 5th, 2022

Two technologies have helped Ukraine fend off the Russian invasion:

While the Russians are able to jam satellite transmissions, so far they have not been able to jam Starlink. Musk has reported that they are trying but so far have not been successful.

The other technology is homegrown and is software known as GIS Arta (GIS stands for geographic information system and Arta stands for artillery).

GIS Arta is an Android app that takes target information from drones, US and NATO intelligence feeds and conventional forward observers, and converts the information to precise coordinates for artillery.

GIS Arta was developed by a volunteer team of software developers led by Yaroslav Sherstyvk. It bears a resemblance to Uber taxi service software, on which the GIS Arta software is modeled.

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GIS Arta makes it possible to do two things not possible before: Targets can be identified and verified visually almost immediately, and artillery and rocket systems can fire quickly and accurately.

Consider that typically it takes 20 minutes to program coordinates into an artillery piece and fire the weapon. Complicating that is verifying the target; for the US that also includes making sure there isn’t a risk of collateral damage.

The artillery previously used by Ukraine was mainly Russian and its firing system was dated and slow. GIS Arta not only changed that but also significantly improved accuracy.

GIS Arta reduces the time to fire to about 30 to 45 seconds. No Western artillery system is as capable and none apparently has the accuracy offered by GIS Arta. According to reports, Ukrainian artillery can now hit a far-away target with an accuracy of between 18 and 75 meters.

Ukraine has also modified its deployments of artillery, separating units by greater distance to make them more difficult targets for Russian counterfire. That, too, has been enabled by GIS Arta.

The GIS Arta complex also selects which gun or rocket system to use and automatically provides the coordinates to any selected system. In fact, the system is so good that Germany, which has already delivered some of its Panzerhaubitze 2000 tank howitzer 155mm mechanized guns to Ukraine, reportedly has integrated GIS Arta.

Your suburban home will not offer true cover

Saturday, June 25th, 2022

Your suburban home will not offer true cover:

Tested against gypsum drywall (Sheetrock), .22 LR cartridges penetrated eight inches, while higher velocity and larger calibers, like .22 Magnum or 9mm and .45, penetrated up to 12 inches. Note that each panel is usually 5/8ths of an inch thick.

Against cinder block, only bullets larger than 9mm caused structural damage. It took multiple shots to crack the block. One .357 Magnum round would “chunk” the brick and multiple rounds caused the brick to fail. Various sources have reported that anything smaller than 9mm will not seriously damage cinder block, but multiple shots from larger calibers may damage the block sufficiently to penetrate.

Shotgun slugs easily penetrated drywall and destroyed cinder blocks; shot tended to ricochet off the blocks without causing damage. Buckshot penetrated 12 inches of drywall and birdshot penetrated two inches.

Canadian researchers fired .38 Special, 9mm, and .40 caliber rounds from handguns and found a third to two-thirds loss of velocity after bullets exited a simulated stucco exterior wall. Wood and vinyl siding covered walls caused about a 15% loss of velocity after penetration. Stucco walls were the most durable, which would slow a standard range type bullet down to about half-velocity.

However, bullets traveling at even 500-700 feet per second are deadly.

[…]

Clay and concrete bricks (solid) exhibited strong bullet resistance. Large-caliber high-velocity hunting rounds (7mm-.30 caliber) created holes and cracks but did not penetrate. This is consistent with US military testing that multiple rounds centered in one place were required to penetrate solid blocks.

Drones and hypersonic missiles in the 1960s

Saturday, June 18th, 2022

A few years ago I read and enjoyed Skunk Works, about Lockheed’s legendary Advanced Development Project. I just recently got around to listening to the audiobook version of Kelly: More Than My Share of It All, the autobiography of Clarence L. “Kelly” Johnson, the famed aerospace engineer behind the U-2 and the SR-71 Blackbird.

A few things stood out as at least mildly prescient for a book written in 1985. First, he expected planes to become pilotless soon. His experience with the D-21 drone in the 1960s helped there. Second, he mentioned that an SR-71 variant, the YF-12, was designed as a high-altitude interceptor with missiles that, when launched, quickly went hypersonic, because the aircraft was already going Mach 3.

The notion of integrating stand-off weapons (SOWs) on the A-10 was first hatched 10 years ago

Saturday, June 11th, 2022

There is a joke that discussions of getting rid of the A-10 started 2.5 minutes after the last one rolled off the Fairchild-Republic assembly line in 1984. How does a jet under constant threat of divestment adapt and evolve to support the ever-changing mission?

The notion of integrating stand-off weapons (SOWs) on the A-10 was first hatched 10 years ago, but never gained traction due to the threat of divestment. […] The first proposal was the ADM-160 Miniature Air-Launched Decoy, also known as MALD. Carried by the F-16 and B-52, the MALD is a low-cost combat capability that offers mission and combatant commanders the opportunity to saturate an air defense picture and increase the survivability of our 5th-gen assets. When planned and utilized properly, a few dozen decoys can wreak havoc on the defenses of a sophisticated potential enemy like Russia or China.

The A-10C has up to 10 weapons stations available. In today’s Air Force, where new fighters have fewer weapons stations in order to prioritize internal carriage and stealth, the A-10’s sheer volume of available weapons stations is a force multiplier. The MALD weighs about 300 pounds and has a range of approximately 500 miles. It is programmable and aims to duplicate the signatures and flight profiles of combat aircraft, inducing confusion and noise into the enemy air defense picture and complicating their tactical decision-making. A single MALD can be loaded directly onto a station, or two MALD can be loaded on a triple-ejector rack. This enables a single A-10 to carry up to 16 MALD, which is as many as a B-52 can hold and 12 more than an F-16 can. To further break it down, a four-ship formation of A-10s could bring up to 64 MALD to a fight. The A-10’s robust, agile combat employment capabilities (low maintenance footprint and ability to operate from unimproved or makeshift runway surfaces) combined with the ability to carry 16 MALD per aircraft, provides combatant commanders the ability to create multi-axis problems, target saturation, and horizontal escalation options for adversaries. No software integration with the jet’s central computer is required. Carriage and separation testing is the only cost to consider.

[…]

The second proposal, the AGM-158 Joint Air-to-Surface Standoff Missile or JASSM, is the next step in the A-10’s evolution of mission support. The JASSM is a low-observable, air-launched cruise missile, which has become so strategically important to combatant commanders, that it has been integrated onto the F-15E, F-16, F/A-18, F-35, B-1, B-52, and even the B-2. Initial assessments and theorizing suggests that the A-10 could potentially carry four to five of the missiles. For comparison, the F-15E is the only fighter that can carry more than two JASSM (the Strike Eagle can carry up to five JASSM), while the bomber fleet can carry between 12 and 24 of the munitions, depending on the platform. Although this may not have the same sticker shock associated with the MALD, the A-10 can offer combatant commanders an additional four to five JASSM per sortie, and leverage integrated combat turns (ICTs) to increase sortie production. Risk mitigation demands more SOWs employment, and the carriage capacity combined with the quick-turn capability of the A-10C should be considered as a means to increase the Mass the USAF can provide to a combatant commander. This is not about taking the JASSM away from bombers and other fighters. This is about bringing more weapons to bear in a shorter span of time, which is a critical component of massing fires.

[…]

Imagine a rapidly-deployable force of non-nuclear fighters that can operate from the most austere locations with a minimal footprint while providing long range fires, decoys, electronic attack, and mission support. That vision is achievable at minimal cost by using assets and capabilities that the Air Force already has, but simply needs to integrate. That is what stand-off weapon integration on the A-10 can provide to combatant commanders.