The carbon brake disc shattered at 2:47 AM, and with it, Jack's confidence. Six radial cracks exploded from the mounting hole, instantly reducing the aerospace composite to worthless scrap.
"Bloody hell," Charlie murmured quietly.
Jack didn't move. His mind, usually a clean machine for calculation, was running on a loop: Interlagos, January 25th. Seven weeks remained to turn theory into racing reality.
For the next two hours, Jack meticulously documented the wreckage: high-resolution photos, measurements taken to three decimal places, and fracture analysis that confirmed his central fear—thermal brittleness at 350 degrees Celsius.
Charlie's voice cut through the silence. "Mate, stop staring. You promised Pace safety. You need help. Call California."
Jack didn't need convincing; the failure was too fundamental. "You're right," he conceded, reaching for the phone.
A heavy, static-laden connection bridged the distance to America.
"Bressler."
"Tom, it's Jack Hartley at Brabham. Give me the details."
Jack delivered a precise, emotionless report: temperature, applied load, the precise pattern of the radial cracks. The silence on the line was long and heavy.
"That's outside the expected range," Tom stated. "We didn't simulate the intense thermal cycling racing brakes endure."
"So where do we go from here? Seven weeks until Brazil."
"You chart the failure envelope," Tom ordered. "I'm sending three more sets of discs via express freight; they should hit your shop Friday. Find the break point and the safe zone."
"Then you don't waste another minute looking at the wreckage," Tom shot back. "We fix it in the next batch."
"Systematic work, then. No panic." Tom's advice was grounded. "We don't aim for theoretical perfection; we identify the real-world limits and engineer past them. Call me when the shipment arrives."
Jack slowly lowered the receiver, remaining motionless in the silent workshop. Four days until the discs arrived. Four days waiting—four days for the clock to tick while the entire Brabham team debated the soundness of his carbon project. Four days to decide if he was the type of engineer who stopped when science pushed back, or the kind who pushed back harder.
The next morning, North materialized and dropped a folder of unrelated work onto Jack's desk.
"I understand the experimental brakes failed," North said, his voice meticulously controlled.
"One failure. We are awaiting a new batch of discs to resume testing."
"An expensive failure," North corrected sharply. "When the shipment arrives, you have seven days to validate the concept. Demonstrate reliable performance by December 15th, or the project is terminated."
A deliberate tap landed on the new folder. "Also, this assignment remains a priority. It is due Friday."
North then walked off, leaving Jack marooned with a pile of bureaucratic work that would steal precious hours from his real mission.
The days blurred into a grueling cycle. By daylight, Jack navigated North's assignments—stress calculations, checks, and documentation. After hours, he relentlessly scrutinized his failure analysis, hoping to find a mathematical error. Yet, the conclusion was fixed: thermal brittleness 350 degree Celsius
He worked straight through the lunch hour and dinner, often late into the night. At 11 PM, the shop timer won, plunging the workshop into sudden, total darkness. Jack sat motionless, his calculations rendered invisible. The emergency lighting soon kicked in, casting cold, severe shadows over his isolation.
Charlie emerged from the fabrication shop, tool bag slung over his shoulder. "Jesus, Hartley. Still here?"
"Finishing North's documentation."
"That can wait. The brakes can't." Charlie dropped his bag with a thud. "Come on. Let's grab a pint and you can tell me what mad theory you've been cooking up in the dark."
They walked to The Engineer's Arms, a pub two blocks from the factory. Charlie ordered two bitters without asking.
"You're terrified," Charlie stated, sliding a glass across the table.
"I'm focused." Jack took a long sip.
"No. Focused is working through the failure. Terrified is sitting in the dark redoing calculations you've proven three times over. You need a distraction. Forget the brakes, forget North, forget the bloody math." Charlie leaned forward, his voice dropping slightly. "Did you hear about Hunt?"
Jack frowned, the name barely registering over the hum of his internal problems. "Hunt?"
"Yeah, James Hunt. The word is he's moved to McLaren for next season. Absolute madness, isn't it? That whole crowd is going to be a complete circus, especially with the money they're throwing around." Charlie took a large drink.
Jack nodded vaguely, his gaze drifting over the rim of his beer. Circus. Madness. He needed a reliable solution.
"So what are you actually worried about?" Charlie repeated gently.
Jack didn't look up. "What if I'm wrong? What if my calculations are right, and it simply cannot be done—not with this material. We're pushing carbon past its limit, and Pace is the one who will pay the price."
"Then you'll have done everything humanly possible with the time and tools available. That's all anyone can ask." Charlie set down his glass firmly. "But you're not wrong, Jack. You're a damn good engineer. You're just scared of being responsible for someone's life. Which is the only sensible way to feel about this job."
They finished their drinks in a shared silence broken only by the pub chatter.
"Come on," Charlie said finally, rising. "Hunt and all that noise can wait. You can't. Let's get you home. Fresh eyes tomorrow."
The discs arrived that Friday afternoon, cushioned in foam. They were accompanied by a handwritten note from Tom:
Jack—
Don't rush the testing. Methodical data collection matters more than speed. But also don't overthink it. Sometimes materials just have limitations you have to design around.
The key question isn't "will these work perfectly"—it's "what are the operating boundaries?"
Call me when you have results.—Tom
Jack read the note three times. Design around the limitations. Not fix them. Design around them.
That evening, Jack and Charlie prepared the first test. Neither man mentioned the deadline, North's skepticism, or the heavy weight of the project.
The temperature gauge climbed steadily: 300∘C... 350∘C... 400∘C...
"Brake," Charlie commanded.
Jack pulled the lever.
The disc grabbed hard, holding for three crucial seconds. Then came the soft snap—a hairline fracture radiating from the mounting hole.
"400∘C," Jack recorded, making precise notes. "Partial failure. Unsafe for racing."
They ran the second disc hotter, at 450∘C. It held perfectly. The third, at 500∘C, yielded the same result—flawless performance.
"The pattern's already obvious," Jack noted. "There's a critical threshold temperature."
"Below it, the material can't handle racing loads," Charlie finished, watching Jack. "Above it..."
"Above it," Jack confirmed, "these are the best brakes on the grid."
Over the weekend—the workshop empty except for their determined presence—they systematically destroyed the remaining discs. Each test added a crucial data point to Jack's failure map: 300∘C, catastrophic; 350∘C, catastrophic but slower; 400∘C, hairline fracture; 425∘C, stability under maximum load; 450∘C and 500∘C, perfect performance.
By Sunday afternoon, the conclusion was starkly clear. The carbon-carbon composite demanded a minimum operating temperature of 425∘C. Below that, the material was too brittle; above it, it was nearly indestructible.
Jack called Tom that evening to report the findings.
"So you need to guarantee they stay above 425∘C," Tom summarized. "That's your constraint. Can you guarantee that?"
"If we can get the discs up to temperature before Pace needs maximum braking," Jack conceded.
"That's a huge 'if'. First lap of a cold race—those discs will be lucky to see 200∘C if he's cautious, maybe 300∘C if he's aggressive. It's not enough."
"I know."
"And if Pace needs to brake hard before they're hot enough?"
"Then the discs fail," Jack said quietly. "That's the reality. I can't change the material."
Silence stretched across the line. "So what's your next move?" Tom asked finally.
Jack stared at the data spread across his workbench, the deadline only nine days away.
"I'm going to design around it," he stated. "I can't make the brakes perfect. But I can make them fail gracefully."
"That's smart thinking," Tom commended him. "Most engineers would keep hammering the material. But you're right—with current technology, you've hit the wall. The innovation must come from the system design." He paused. "Be honest about what these brakes can and can't do. That's how you build trust."
After Tom hung up, Jack remained in the quiet, empty workshop, surrounded by broken carbon and decisive data.
He faced a choice.
He could walk into North's office Monday and admit the carbon brakes had fundamental limitations that rendered them unsuitable for racing. This was the safe call. The decision that would ensure James Hartley remained employed for thirty-four years without ever achieving anything memorable.
Or he could spend the next week engineering a solution. He would accept the brakes weren't perfect and would eventually fail. But he would design fail-safes ensuring that when they fractured, Pace could manage it without disaster.
The image of Connor Walsh spinning at Yas Marina—the consequence of always playing it safe—flashed in his mind.
Jack pulled his notebook to him, opening it to a fresh, clean page.
Title: Designing for Graceful Failure
Not perfect brakes. Safe failures.
By midnight, he had rough outlines of three system concepts. By 2 AM, he'd finalized his decision: he would take full responsibility for implementing them, regardless of approval from North or Bernie.
This was his project. His promise. His chance to prove he wasn't the same engineer who'd spent his career avoiding risk.
For four days, Jack barely left the engineering office. He sketched, calculated, revised. Three concepts took shape on paper—systems to manage thermal warm-up, control crack propagation, and provide emergency backup if everything failed.
None of them fixed the fundamental problem. But together, they might make the problem manageable.
Each system went through multiple iterations before the math worked. Nothing was elegant. Everything was a compromise.
On the fourth day, he had complete engineering drawings.
Nothing was perfect. But everything was designed to fail safely.
He rolled up the drawings and headed to the fabrication shop.
...
Tony studied the complex drawings for five full minutes, his weathered face betraying nothing.
Finally, he spoke: "You're designing these brakes to fail."
"I'm designing them to fail safely," Jack corrected, the distinction critical. "There's a profound difference."
"Is there?" Tony pointed a grease-stained finger at the mounting details. "You're deliberately incorporating elements that flex under stress. You're weakening them on purpose."
"Controlled flex," Jack countered. "If a crack initiates, these components will absorb and slow the propagation. They provide the driver with a warning instead of instant structural collapse."
Tony traced the geometry. "And if they flex too much during normal operation?"
"The clearances are precisely calculated to prevent that," Jack explained. "They should provide compliance under shock loading but remain rigid under steady-state forces."
"Should." Tony looked up, his eyes sharp. "That word carries a lot of assumptions."
"I know. That's why the next step is building and testing it."
Tony worked through every drawing, relentlessly questioning assumptions and sketching potential modifications in the margins.
Finally, he set the drawings down. "You know what this tells me? You understand something most engineers never grasp: everything eventually breaks. The only real question is whether it breaks safely or catastrophically."
He rolled up the drawings. "I can build this system. Three days if I work straight through." He paused, delivering a sober warning. "But understand this, Hartley: I'm building your design. If your math is flawed, these brakes could fail in entirely unanticipated ways. That liability rests entirely on you, not me."
"I know."
"Do you?" Tony stepped closer. "Because when Carlos Pace pushes that brake pedal at Interlagos, he's not trusting my fabrication skills. He's trusting your engineering judgment. That's a heavier responsibility than most twenty-two-year-olds are ready to carry."
Jack met his gaze steadily. "I know. And I'm ready for it."
Tony studied the young man for a long moment, then gave a single, firm nod. "All right. Be back tomorrow morning. We'll start fabrication."
Over the next three days, Tony became a machine of fabrication. Each component demanded multiple, tedious iterations—springs precisely calibrated, mounting pieces machined to tolerances measured in tenths of a millimeter.
On the third day, the work was complete. Tony assembled the first prototype brake system, integrating all three safety concepts.
The finished assembly looked alien. It looked wrong—nothing like conventional brake designs. But crucially, it looked like it might actually work.
"Test it on the dyno," Tony instructed. "Push it hard. Try to break it in every way you didn't think of."
Jack and Charlie ran dyno tests for seven days straight.
On the second day, they executed the crucial crack propagation test using a deliberately damaged disc. Jack watched the hairline fracture initiate at the mounting hole, then creep across the surface—slowly, controllably, precisely as his mathematics predicted. Four-point-two seconds elapsed from initiation to structural concern.
"Pedal feel changed at two-point-eight seconds," Charlie noted, monitoring the pressure gauge. "The driver would absolutely feel that."
"Good," Jack confirmed. "That's the warning window."
The emergency backup system engaged cleanly at four-point-one seconds, automatically providing the reduced, but steady, braking force they had designed.
Each day brought minor complications demanding immediate refinement: a spring needing slight adjustment, a clearance that was fractional. But by December 21st, four complete brake assemblies stood ready.
Jack ran one final, critical validation: maximum braking stress at exactly 425 degree celsius. The disc held perfectly.
Not perfect brakes. But brakes designed to fail safely.
Jack spent that evening documenting everything in a comprehensive technical report for Gordon Murray.
He wrote with unsparing honesty: 47 tests conducted over three intense weeks. The complete failure envelope was mapped. The minimum safe operating temperature stood at 425 degree celsius. Three safety systems were implemented. Estimated operational lifespan: five to ten races before material degradation necessitated replacement.
The limitations section was brutally frank:
These brakes will eventually fail—that is inevitable with experimental technology and current material science limitations. However, every failure mode has been analyzed and mitigated. The driver will have warning before catastrophic failure. The emergency systems will provide options for safe management.
This is not mature technology, but it is safe technology if operated within documented constraints.
He framed the last line with immense care:
I take full responsibility for this assessment and these recommendations.
—Jack Hartley, December 22, 1975
Jack sealed the envelope and walked to Gordon's office.
Gordon Murray sat at his desk, surrounded by drawings of the new BT45. He looked exhausted—the fatigue of weeks spent wrestling a fundamentally compromised car into competitiveness.
"Hartley. You're working late."
"Carbon brake report," Jack said, placing the sealed envelope on Gordon's desk. "Complete test results, design solutions, and an honest assessment of all limitations."
Gordon picked up the envelope but didn't open it. "Simple question: Can Pace race these brakes safely at Interlagos?"
"Yes."
"No qualifications?"
"They demand understanding and adaptation from the driver. But they are safe if used correctly."
Gordon's eyes narrowed. "That's a lawyer's answer, Hartley. I need an engineer's answer."
"Then here is the engineer's answer: I've tested them to failure forty-seven times. I know exactly how they break and exactly what warning signs Pace will receive before a catastrophic event. They are as safe as I can make them with current technology." Jack paused, holding the older man's gaze. "And if they fail, that's on me. Not you. Not Bernie. Me."
Gordon studied him for a long moment, then opened the envelope and pulled out the report. "I'll read this tonight. If it's as thorough as you claim, we'll move forward with track testing at Silverstone."
"It is," Jack affirmed.
"We'll see." Gordon was already immersed in the first page. "Get some sleep, Hartley. You'll need to be sharp tomorrow."
Jack walked out through the empty workshop into the bitter cold of the December night. A few weeks ago, a shattered carbon disc had destroyed his confidence. Now, a technical report sat on Gordon Murray's desk—a document that would either prove his value to Brabham or confirm he'd been promoted beyond his competence.
Tomorrow, he would learn which.
The next day Jack's phone rang while he was making tea.
"Hartley." Gordon Murray's voice was flat, professional. "Read your report. It's thorough."
Jack's hand tightened on the receiver, his throat dry. "And?"
"And we're testing them. Silverstone, December 30th. Four days on track. Pace arrives tomorrow for a briefing." Gordon paused for emphasis. "The report's good work. Honest about limitations without being defeatist. That's what I needed to see."
"Thank you."
"Don't thank me yet. The brakes either work or they don't. We'll know in a week."
The line went dead.
Jack slowly set down the phone, his hands subtly trembling. One week until Silverstone. One week until the cold, hard track revealed if a month of work was meaningful.
The sudden gravity of the situation hit him, a stark difference from his life in the future. In his original timeline—2025—he had validated dozens of experimental systems. He'd sent cars onto tracks hundreds of times, never nervous because modern F1 provided an unbreakable safety cell: HANS devices, crumple zones, and Kevlar tethers ensured that if a component failed, the driver walked away with, at worst, bruises. Engineering failure meant disappointment or a budget review.
But here, in 1976, failure carried a different price.
The weight of his engineering judgment was no longer tied to job security or embarrassment if Bernie pulled the project. It was connected directly to the survival of Carlos Pace.
He remembered Gordon asking why he hadn't quit the project when the first disc shattered. He couldn't articulate the truth then, but he knew it now: he couldn't spend another lifetime in the middle, making safe choices that kept him employed but never exceptional.
Yet, taking risks in 1976 meant something entirely different. In this era, the job description for a Formula 1 engineer came with brutal baggage: every system he validated, every promise he made, carried the cold, unforgiving knowledge that catastrophic component failure meant more than just a DNF—it meant a fatality.
Jack had designed for graceful failure. He had built in redundancy and been scrupulously honest about the 425 degree celsius constraint. But the brakes were still experimental. They were still dependent on track conditions, driver behavior, and the fundamental chaos of actual competition.
He needed to get used to that weight. He needed to carry that crushing responsibility without letting it paralyze the very innovative thinking that had brought him this far. He needed to learn how to take ownership of outcomes he couldn't entirely control, because that was the only way he would ever build his own team.
Jack finished his tea and started packing for the test. The time for calculation was over.