HsB

The series are supersonic stealth bombers, developed and deployed by Academy City. All currently known iterations have a top speed of 7000 kilometers per hour.

Appearance
The HsB's length varies but it is considered to be around, most often, at least 80 meters long to 100 meters. Its actual design however differs between the visual mediums it has been depicted in.

In the anime, the HsB is depicted in the shape of a. It has a curved nose with a curved bar connected to the front, and a pair of engines under either side of the main wing. A cargo bay is located at the rear of the craft with vertically opening doors. There are pair of additional wings, one under the other with a small gap between them, extending from the tips either side of the primary wing.

In the manga, the HsB has a design (specifically the cranked arrow variation) with a pair of diagonally orientated fins either side atop the delta wing and  near the pointed front. It has two long engines below the delta wing, one on each side. The design of HsB changed in Toaru Majutsu no Index Manga Volume 22 to anime design.

Specifications and Capabilities
HsB-02 is apparently the second iteration in the HsB series of supersonic bombers, and is the first one chronologically seen being used by Academy City. Though it isn't known if it was also the case for the previous HsB, the HsB-02 was created using the same technology used in the Supersonic Passenger Plane that Kamijou Touma and Tsuchimikado Motoharu had taken to Avignon. The bombers are so fast that they can shake off a missile just by flying straight through the use of pure speed alone (as it cannot make sharp turns), as well as go from Japan to France in just under an hour.

It's length varies but it is considered to be around, most often, at least 80 meters long to 100 meters. Due to its large size and the incredible speed it takes, the outer skin's temperature approaches 1000 degrees on full speed, and as such the HsB-02 has a built-in cooling system, using liquid oxygen and hydrogen, which are also used as fuel, coolants that are flowed through pipes in the entire plane. Its frame is the basis for HsF-00 planes.

Although used as a bomber, the plane is capable of transporting large objects, such as Powered Suits like the HsPS-15, goods, and people. The aircraft is operated and maintained by a conventional crew.

Weapons
As it is a stealth bomber, it is equipped with conventional bombs. However, it has some other weapons:
 * Earth Blade: An elongated black blade mixed with iron sand slices through the air at supersonic speeds, it was so designed as so it can easily contract via electricity. The blade slicing through the air at that speed creates a destructive power from the wind currents, however, with the iron sand being accelerated to a speed over 10,000 kilometers per hour, the plane can create a blade of molten metal and heated gas that is is around 8,000 degrees Celsius. The Earth Blade's pattern can be precisely controlled by electricity, and can form curves and straight lines, as well as targeting single spots. It is accurate enough that it is described as being able to make a jigsaw puzzle piece. Multiple lines can be used by the bombers if need be. The effects of the blade can cause the earth to be superheated to resemble like magma. According to Accelerator, if it had 3 kilograms of iron and an hour, it could cut the entire Eurasian continent in two.

For the equipment variation known as Style 3 (三式), the HsB is loaded with various explosives, including special bombs which can destroy facilities deep underground and Synchronous Multilayer Bombs to destroy only a designated area, collectively capable of annihilating a manmade island.

Specifications and Capabilities
HsB-07 is the updated version of the HsB-02s that were used in World War III. The most notable change in the design of the bomber is its borrowing the operating mechanism of the HsF-00, where most of the pilot's body is frozen to protect the pilot from the massive Gs the aircraft is subjected to. With this, the pilot need not use their fingers to operate the aircraft and need not use their mouths to communicate with their allies. The distribution of blood in the pilot's brain, the amount of chemicals secreted, the flow of electronic signals, and monitoring of the active regions of his brain with sonar were some of the methods of directly gathering information from his brain. The accuracy of each method was low, but that could be overcome by using multiple methods. The technology had also begun to be used experimentally in intelligence and criminal investigations.

Weapons
It is unknown if they still retained Earth Blade, but since they're bombers, their primary function was to drop bombs upon their targets. They can use conventional guided bombs as well as chemical warheads.

Politics
Academy City had broken agreements with the Japanese government regarding the manufacturing of bombers at the time of the Avignon incident. It is unknown if this agreement has been reestablished or if Academy City had to answer for it breaking the agreement.

Toaru Kagaku no Railgun SS: Liberal Arts City
During the attack on the Liberal Arts City by the Return of the Winged One, while Academy City students were there on a field trip, several HsB-02s were put on Level A Standby and lined up on one of School District 23's runaways, loaded with the Style 3 variation of bombs and a prototype AIM sensor on the nose to detect a specific esper, though it would only detect one at Level 5 strength from its performance and the height of the planned bombing. If sent out, they were intended to annihilate the island while only recovering Misaka Mikoto, however in the end they weren't deployed.

Document of Constantine Arc
The HsB-02 was first deployed during the suppression of Avignon, carrying HsPS-15s. Here, they used the Earth Blade, destroying several structures in the city, and later would've bombed it if not for Accelerator's vote to change the plans.

World War III Arc
As part of the Academy City military, the bombers were sent to World War III, bombing several targets in Russia as well as deploying Powered Suits as well as other units and supplies onto the battlefield. On October 30th, Misaka Worst was dropped off into Russia by one of them. Mugino Shizuri was also taken into one of the bombers to be dropped off into Russia, as well as Misaka Mikoto who hijacked one of them. Following the rise of the Star of Bethlehem, a number of them were cut down by the summoned Archangel Gabriel.

Baggage City Arc
HsB-07s were deployed during Academy City's suppression of Baggage City, using them to cripple the city through bombing of important locations. Several of them, most notably one being piloted by Rokudou Ryuuichi, were later destroyed by Marian Slingeneyer's magical artifact, Loki's Net.

Magic God Othinus Arc
Supersonic bombers were deployed by Academy City during the GREMLIN invasion of Tokyo from Academy City directly toward Sargasso, GREMLIN's base, but were intercepted and supposedly swept away by Mokkerkalfe waiting for them and under the control of Ollerus, who was forced to keep up the ruse of being Thor.

Trivia

 * Going by the patterns for Academy City's weapon naming schemes, likely stands for.