The military-industrial scientific research system of the academic master

"New technology?"

Shapur Collinger frowned slightly:

"Tell me about it."

As an old-school engineer, although he does not reject various new technologies per se, he does not want to branch out from the original plan.

From an engineering perspective, every change in the R\u0026D plan midway means the introduction of new uncontrollable risks. Even if additional time and funds are spent, it is difficult to ensure that the overall reliability performance returns to the original level.

If there were a few more accidents in the middle, it would be completely impossible to end.

Haste makes waste.

Once the delay is too long and the external environment changes, Party A will naturally provide new demands, which in turn will force Party B to modify the R\u0026D plan again, forming a vicious cycle.

Over and over again, it can easily lead to the project becoming an unfinished project with huge sunk costs.

Therefore, Collinger's original plan was to modify the aerodynamic shape of the waverider-like front section of the X51A to reduce the resistance during the initial acceleration process, while optimizing the shell structure and reducing the overall weight of the aircraft.

This allows the entire flying body to reach a speed of Mach 5.5 before being thrown away from the booster without changing the core power system, ensuring the startup success rate of the SJX61-1 scramjet engine.

However, although this method has the least risk, it leaves no room for opportunism.

Extensive numerical calculations and wind tunnel testing are required to ensure the aerodynamic and structural balance after modification.

But the problem is that in NASA’s hypersonic wind tunnel, only the gas flow rate meets the requirements, and the total air flow temperature and duration of a single test are not enough to fully restore the actual hypersonic flight conditions.

Judging from the current situation, I am afraid that it will not be able to meet the new requirements imposed by the above.

Just listen to Charlie Brinker's advice.

The other party is almost 20 years younger than Collinger and is a rising star who only entered the hypersonic project in 2001.

Similar to many researchers of the same age, there is still a gap between the basic skills and the older generation, but the advantage is that the thinking is more flexible.

When the superiors initially appointed Brinker as Collinger's deputy, they also had the idea of ​​​​learning from each other's strengths and weaknesses.

The former was obviously well prepared and answered almost without thinking:

"The time given above is very tight, and it will definitely be too late to temporarily modify the aerodynamic and structural design of the waverider-like body. And if the boost section is simply extended, it will also increase the weight and may not be able to obtain sufficient benefits. Secondly, it will also need to be reworked. Writing a flight control system is equivalent to affecting the whole body. "

“So, a simpler and more effective way is to directly modify the boost section to obtain stronger propulsion performance while keeping the volume and weight distribution unchanged, so as to ensure that the speed at the end of the boost section can meet the requirements of the scramjet engine. startup requirements.”

This idea is indeed simple.

As the saying goes, bricks fly with great force.

It is also very consistent with Boeing’s excellent tradition.

However, Collinger's frown did not relax at all:

“In my experience, engineering simplicity often means technical complexity.”

He said in the tone of someone who has experienced it:

"Although the X51A's design indicators are radical, most of the project's technologies have actually undergone different forms of technical verification in the past. What really determines success or failure is this power system composed of a solid rocket-scramjet engine."

"In order to meet the thrust and working time requirements under hypersonic conditions, SJX61-1 has been set to a very extreme working boundary. The reason why the power section of ATACM was selected as the booster was also out of prudent considerations. If it is rashly used now Improvement, the accumulated risks..."

In fact, in addition to the above concerns, Collinger has another reason that he has never stated clearly——

Like most colleagues engaged in aircraft design, his research in the field of aerodynamics is not very deep.

The scramjet engine, including the X51A, is also developed and produced by Pratt \u0026 Whitney.

But this was decided upon when the project was first established. It is a single-project contractor and has the same status as Boeing. The two parties are in a cooperative relationship recognized by Party A.

Because the boost section was borrowed, as an integral part of the aircraft, it was handed over to Collinger's technical team for integration.

It's integration, not R\u0026D.

Now that the project is halfway through, it is simply not feasible to overturn the contract and add another individual project contractor.

Therefore, if you want to make a fuss about solid rockets, you can only take the path of subcontracting layer by layer.

Colin's style is old-school, and he really doesn't like the feeling of losing control at any time.

What's more important is that if something goes wrong with this kind of subcontracted work, he, the second party in the contract, will have to take the blame.

However, Brinker was very positive about this matter and was not discouraged at all by Collinger's hesitation:

"Mr. Supervisor, according to our previous test results of the boost section, because the ATACM power section uses a larger filling ratio, the actual effective working time can even be extended to more than 40 seconds."

While talking, he even took out a printed test result from nowhere, obviously prepared:

"It's just that at the end of the operation of the solid rocket motor, strong and irregular pressure oscillations will occur in the combustion chamber, accompanied by an increase in the average air pressure... In order to avoid this unstable operating curve, we changed the boost stage Working time is limited to 29 seconds."

This test was a task that Collinger personally assigned a few months ago. It still has an impression on him, so he quickly captured what he meant:

"You mean to extend the working hours of the boost phase?"

Brink nodded and was about to speak when he heard the other party change the subject again:

"No...no."

Collinger pointed to the rising air pressure curve 30 seconds later on the graph:

"After 30 seconds, although the boost stage still seems to be working normally, the coupling of the fluctuating heat release rate and pressure oscillation during propellant combustion may have a gain effect on the air pressure amplitude."

"I have seen the design of Army tactical missiles. The structure is relatively simple and rough and not sensitive to this kind of shock. However, the speed of X51A is too fast and the structural redundancy is relatively small. It is very likely to cause the engine to deviate from the design state or even disintegration……"

Brink seized this opportunity and rarely jumped in directly:

"But director, what if there is a way to ensure that the solid rocket motor continues to burn stably within 30-40 seconds...or in other words, there will only be a certain pressure oscillation without an increase in the average air pressure?"

Collinger was not angry at being interrupted, but looked surprised:

"Ah?"

Immediately afterwards, he looked at the deputy with suspicious eyes:

"I know that you conducted solid rocket-related research for a period of time before joining the company, but the unstable combustion phenomenon of dual-base propellants is a problem that has not been completely overcome for decades. Your statement is just to extend it by one-third. Stable working hours..."

He was still guessing in his mind just now, thinking that Brinker might suggest that he add high-energy oxidizers, such as RDX or Octogen, to the composite propellant to increase the energy of the propellant.

But I never expected that it would be this kind of plan.

Of course, having said that, extending the working time of the boost phase does have the least impact on the overall design of the X51A... It can even be said that there is almost no obvious impact.

The extra workload extended is just to modify a few small modules in the flight control involved in scramjet engine startup.

Something that can be done in a few dozen man-hours at most.

Seeing that Collinger was speaking out about his integrity and still questioning his attitude but his attitude had obviously changed, Brink quickly gathered strength and took out a new page of charts:

"Supervisor, look, according to the current calculation results, the boost stage can accelerate the flying object to about Mach 4.9 after 29 seconds of operation. So if it can be extended by another 10 seconds, it will definitely be able to reach a separation speed of Mach 5.4-5.5... And we don’t even need to recalibrate this engine, we just need to set a trigger gate to automatically jettison the boost stage after detecting that the speed exceeds Mach 5.5!”

Having said this, he flicked the edge of the paper in his hand and made a crisp "pop-" sound.

The former had no other options at the moment. His expression changed from gloomy to bright for a long time, and finally he gave in helplessly:

"What about the specific technical solutions?"

At this point, Brink knows that although the matter has not yet received final approval, it can be said to be a certainty.

"This technology was developed by Dr. Mellie Hurst of the Massachusetts Institute of Technology. You may need to contact the other party for specific circumstances."

He replied:

“In general, the idea is to introduce a metal…or more specifically, an aluminum oxide nanoparticle catalyst into a traditional AP/HTPB dual-base solid propellant to optimize the burning rate ratio between the two solid fuel particles. , and improve the linearization level of propellant surface thermal feedback and combustion rate.”

This explanation was quite clear and logical, and it had eliminated all of Collinger's concerns.

As for the more specific content, as Brink said just now, it must be discussed in detail with the technical personnel actually responsible for the research.

"All right……"

Collinger finally relented:

"How should we contact Dr. Hurst?"

"I have her business card here..."

Brink took out his wallet and took out a small, beautifully printed card:

"But in the final analysis, they still take advantage of this kind of thing, so I will ask the other party to contact us proactively and send more detailed technical information."

Similar to the situation in all other industries, subcontracting must be the grandson of the general contractor.

Collingie didn't like to engage in subcontracting, but that didn't mean he didn't understand the twists and turns involved, so he just casually took the business card and glanced at it:

"Ask them to contact the legal department as soon as possible regarding the subcontract..."

He originally wanted to try to spread some risk through subcontracting.

If something goes wrong, you can't let yourself take the blame.

But just in the middle of the sentence, he stared at the business card in his hand and froze.

After hesitating for a moment, he still expressed his thoughts:

"This Dr. Hester...seems to be much younger than I thought..."

Then he quickly added:

"Of course I'm not saying that a young lady can't achieve outstanding research results, but she looks like she just graduated from a bachelor's degree..."

Halfway through speaking, Collinger raised his head and looked at Brink:

"I remember that all your degrees were completed at Cornell University. Why do you know a doctor from MIT who is not very famous?"

The latter obviously did not expect to be asked such a question, and a look of confusion flashed across his face.

In theory, this is a private topic, so I don't need to answer it.

But after all, it's about the project, so I explained:

"My doctoral advisor later jumped to MIT, so this... can be regarded as my junior sister to some extent, including this new composite propellant research topic, which was also shared with me by my advisor some time ago."

This explanation is reasonable, so Ke Lingjie didn't continue to dwell on these details, but just put the business card in his pocket:

"I hope to meet with her within a week... It's better to meet with your advisor together. Some things are difficult to explain clearly through phone calls and emails."

"Okay, I'll contact you right away!"