Chapter 1005 Explosive Shell Test

Regarding manufacturing quality, fuzes made by naturalized citizen workers proved no worse than those made by Senators; the difference in firing rate was negligible. It appeared Lin Shenhe's efforts to simplify fuze structure had ensured that naturalized citizen workers with lower technical levels could indeed produce qualified products.

As for safety, testing confirmed that dropping from twelve meters to impact the ground without pulling the safety pin guaranteed no accidental firing.

However, the Ordnance Group wasn't satisfied with merely meeting functional requirements. Any industrial product also had material cost control and mass production organization needs to address. Fuzes, as consumables, had to be as cheap and easy to produce as possible. Though phosphor bronze springs could be self-produced, within Lingao's industrial system they qualified as "high-grade precision components," belonging to the Planning Bureau's "Level 2 controlled materials."

Currently, phosphor bronze springs were primarily used in relatively precise industrial equipment, such as the timekeepers and instruments Dr. Zhong had been wholeheartedly developing—their production cost was substantial.

Ideally, more inferior, easily obtainable materials could substitute. After considerable thought, Lin Shenhe sought out Zhan Wuya and asked whether he could heat-treat wrought iron wire.

"Of course, but what do you want heat-treated wrought iron wire for?" Zhan Wuya asked, puzzled.

"To make springs—for artillery shell fuzes."

Zhan Wuya stared at him incredulously. Springs for artillery shell fuzes had been a frequently discussed stumbling block, and now Lin Shenhe was telling him he wanted to use heat-treated wrought iron wire.

The Industrial Committee produced wrought iron wire of different gauges according to old dimension standards; higher grades were even galvanized. Wrought iron wire had broad applications throughout the Senate's industrial and agricultural production; Lingao Telecom's telegraphs were also strung using wrought iron wire.

Lin Shenhe produced a fuze structural model—a proportional cross-section model he had commissioned from the machinery factory—and explained the specific working conditions and principles in detail. Zhan Wuya studied it for a long time before finally agreeing to try with iron wire.

They selected twenty-gauge galvanized wrought iron wire. Using a specialized spring-coiling machine, they wound the wrought iron wire into springs, then heat-treated them.

Subsequently, Lin Shenhe conducted comparative tests between wrought iron wire springs and phosphor bronze springs using testing equipment. He himself knew perfectly well that these two types of springs having completely identical performance was impossible. The results naturally didn't surprise him.

"It seems they can't substitute," Zhan Wuya observed.

"Let's try firing them from artillery," Lin Shenhe replied, unwilling to give up.

Fuze shells fitted with wrought iron wire springs succeeded when fired with strong charges from mortars, with safety and firing rate no worse than phosphor bronze springs. But firing from the seventy-millimeter cannon yielded poor results, with multiple spring failures—high-bore-pressure rifled cannons were far more demanding on fuzes.

Lin Shenhe expressed satisfaction with all test results and decided to proceed with formal live-fire testing using actual charges.

The black powder charge columns sent for drying had all cured naturally. The final process was coating charge column surfaces with shellac varnish dissolved in alcohol at specified concentration. This provided both moisture protection and prevented cracking and deformation.

Shellac was imported from India and Vietnam, being lac insect secretions. It had broad uses in industrial fields; for an industrial system like Lingao's, which lacked chemical products, lac's importance as natural resin was even more significant.

The Machinery Department's weapons enthusiasts began filling artillery shells. High-compressed black powder charge columns could no longer be simply detonated with fuses; ignition devices—blasting caps—had to be used.

Manufacturing blasting caps was quite dangerous, though technically not difficult. The process involved rolling kraft paper into tubes, then filling primer with a press, and finally sealing. Previously, to reduce danger, the military-industrial department had rarely manufactured blasting caps. Explosive weapons based on black powder generally didn't require them; only when using dynamite and ammonium nitrate explosives were small quantities produced.

The Special Chemicals Complex Research Center No. 1's warehouse stored small quantities of blasting cap shells and safety caps. Blasting cap shells were rolled from kraft paper, coated inside and out with shellac varnish in alcohol at specified concentration for moisture-proofing. Lin Shenhe personally selected twenty for use as experimental shell blasting caps.

Common blasting caps were divided into single and compound types. Single type contained only mercury fulminate; compound type had mercury fulminate on top and booster charge below—typically TNT or RDX.

Because the Chemical Department couldn't produce TNT, all blasting caps previously manufactured by the military-industrial department were single-type. This time, to ensure effective detonation, Bai Yu suggested manufacturing compound blasting caps. But Lin Shenhe opposed the idea—no matter how capable they were, they couldn't conjure TNT from nothing.

"We could use stockpiled ammonium nitrate explosives, and don't we still have the explosives Landu brought?"

"This is pointless—we currently can't mass-produce either one. We should test according to industrial mass production conditions."

Finally, they decided to continue manufacturing single blasting caps. In the blasting cap workshop, Lin Shenhe carefully loaded mercury fulminate into tube shells in several batches, then lightly pressed down with a press. For safety, he operated standing behind thick steel plate, wearing an explosion-proof helmet. Mercury fulminate was extremely sensitive; explosions during pressing occurred easily.

After the mercury fulminate powder was pressed, he picked up a safety cap made from galvanized sheet iron—containing a thin silk piece inside—fitted it onto the tube shell, and turned the press handle.

According to technical requirements, the press compressed the safety cap into the tube shell with specified force per square centimeter. Lin Shenhe checked that the join was complete, then used a brush to carefully sweep away powder scattered on the tube shell, collecting the scattered mercury fulminate into waste containers. Finally, shellac varnish in alcohol was applied to the tube shell bottom, completing one blasting cap.

Then, at the test site, another blasting cap trial detonation was conducted. Shells with new blasting caps were fitted with fuzes and underwent striking tests according to combat requirements, ensuring the fuze striker could effectively strike the blasting cap.

The first striking failed—the striker position was inaccurate. Jiang Ye adjusted on-site; the second immediately succeeded. After several consecutive tests, every blasting cap was accurately struck.

Lin Shenhe nodded. "Now we can assemble." He signed the assembly task order, formally ordering assembly of explosive shells with new fuzes.

The new fuzes were finally ready for their formal debut. The seventy-millimeter rifled cannon borrowed earlier remained at the range. Lin Shenhe also borrowed a twenty-four-pounder smoothbore howitzer—lacking mortars, and finding mortars not quite suitable anyway, he used this as a temporary substitute.

"Can conical shells also be fired from smoothbore cannons?" Zhan Wuya asked.

"Of course," Lin Shenhe replied. "Mortars don't fire spherical shells either."

Simple rails had been laid at the range. Railcars transported forty newly produced shells for both cannons: half with phosphor bronze springs and half with twenty-gauge wrought iron wire springs.

"Twenty-four-pounder howitzer, Shell A, load one!" Lin Shenhe commanded from the bunker through a large tin megaphone. An artillery crew from the Army Instruction Corps responsible for cannon firing quickly opened the wicker shell crate, retrieved a shell, and attached the fuze. One gunner loaded the silk propellant bag through the muzzle into the bore; the loader then inserted the shell.

The gunner fitted the firing tube at the rear firing port and attached the lanyard—for safety, the lanyard was particularly long, extending all the way to a bunker twenty meters away.

At a whistle signal, all gunners ran together to jump into the bunker. Warning sirens for live-fire testing echoed overhead.

"Fire!" Lin Shenhe yelled, then quickly ducked back into the bunker, pressing his eyes to the binocular periscope newly made by the Optical Workshop.

The gunner gave a hard pull on the lanyard. The twenty-four-pounder howitzer roared, the heavy gun body recoiling backward, ejecting thick white smoke. Through the periscope, the shell's trajectory arcing through the air was visible—under the smoothbore and brown powder combination, muzzle velocity remained somewhat low.

The shell landed accurately in the designated impact area. A flash of light—it exploded.

The explosion's power, even visually, was obviously much stronger than primitive spherical black powder explosive shells—those shells' explosions after landing merely raised a cloud of black smoke, kicking up relatively little dirt.

"Let's go see." Lin Shenhe hurriedly climbed out of the bunker and, together with Jiang Ye, Wang Ruixiang, and several military-industrial department apprentices, boarded the farm vehicle, bumping along the dirt road toward the impact area.

The twenty-four-pounder explosive shell had left a crater half a person deep in the impact zone, still wisping smoke. The air was thick with black powder's pungent smell. Lin Shenhe squatted down, examining the soil at the crater's edge. Several students interning at Research Center No. 1 quickly spread out, searching the surroundings for shell fragments and marking their positions on the map.

"Look—with greater charge power, the shell fragmentation is also stronger than before." He pointed at the collected fragments.

Not only did fragments fly farther than before, but fragmentation was also greater than with spherical shells. Previous spherical explosive shells, after exploding, produced only twenty-odd large fragments—some even only burst into seven or eight pieces—unable to form dense fragment kills. Even the largest-caliber mortar shells with maximum charge couldn't produce more fragments.

But now, simple searching within five meters of the crater found over seventy fragments of various sizes. Lin Shenhe pointed out that if shell body materials could be further improved and pre-formed fragmentation measures adopted, post-explosion fragment effects would be considerably enhanced.

Firing Shell A with phosphor bronze springs from both cannons: all twenty firings succeeded. Testing Shell B fuzes: complete success on the twenty-four-pounder smoothbore. But on the third firing from the seventy-millimeter rifled cannon, everyone in the bunker felt only a flash of light; a huge muffled boom transmitted through the ground, and the earth trembled slightly—the shell had exploded in the bore.

The fuze's technical details come from Lin Shenhe's own testing. Due to sensitive content, some details are not written. Readers may understand the general idea.

(End of Chapter)