TECHNICAL TEAM ON K9 PROJECT
Colonel NGUYEN TRUNG THANH
Former Vice Chairman of Technical Affairs
President Ho Chi Minh Mausoleum High Command
The design team and construction supervision of the K9 Project (Da Chong), where President Ho Chi Minh's body were preserved before the construction of the Mausoleum, consisted of 6 engineers from the Design Department of the Military Command - Combat Engineer Headquarters: Construction Engineer Nguyen Trong Quyen - Head of the direct management team; Engineer Nguyen Cao Dam in charge of construction; Engineer Bui Danh Chieu in charge of air conditioning and ventilation equipment; Engineer Hoang Quang Ba in charge of water supply; Electrical engineer Pham Hoang Van responsible for construction coordination, and myself, Nguyen Trung Thanh, in charge of the electrical and automation systems. During this period, the six of us lived and worked continuously on the construction site under extremely difficult conditions.
In the morning, we would grab a boiled cassava and head to the construction site, and for lunch and dinner, we had job's tears with dried fish, sharing the mess hall with the construction unit. During leisure time or in the afternoon, on Sundays, we would go fishing to improve our meals.
I was responsible for 4 tasks:
- Designing and supervising the construction of the backup power system. Although it was intended as a backup, during the war, the national power grid was almost unavailable, making this system the main power source.
- Monitoring and inspecting the installation of the 35kV high-voltage line and substation to supply the electricity grid for the project.
- Designing and supervising the construction of the central management room No. 7, controlling the air conditioning and water supply systems to maintain the required temperature and humidity for preserving President Ho Chi Minh's body.
- Designing and installing a special lighting system for visiting President Ho Chi Minh.
A series of technical issues needed to be solved, and my job was to select design solutions that were suited best to the schedule, construction expertise, and the supply of materials at the time. Often, while walking and thinking about solutions in my head, I would pick up a piece of cement paper to brainstorm rough ideas, and in the evenings, these graphs would be presented to the construction workers. In the morning, rolling up my pants, I walked for several kilometers through the jungle with the electrical workers from Ha Dong Electric Branch to supervise the construction of the high-voltage line leading to the project. On the way back at lunch time, I felt a sense of starvation, with low blood sugar, I had no way but to sit leaning against an electric pole to rest. If I had a piece of candy to suck, I could recover and keep on the walk immediately, but it was just impossible in the middle of the forest. Sweat soaked my clothes, and my limbs were covered in mud. I possibly fainted on the way back, but thanks to the youth's strength, taking a short break allowed me to keep going. Being back home, the meal was no longer warm, and I had no choice but to finish the meal quickly, solving the hunger. When the trained electricians came back to read the drawings for the automatic control room, I would tear off a piece of cement paper, split it into parts, and use it for interpretations. However, the prior instructions could not stop me from personally going to the construction site guiding the workers. Holding pliers, I would bend the crooked wires as a sample, and measure various diodes, ensuring errors free. As I used to be a labor worker, I understood my instruction was easy access for workers, and the construction process would go smoothly. While working with construction workers, Mr. Hanh - in charge of project material supply - said:
"I've been directly to the electrical equipment manufacturing plant, asking for materials needed, but they are not available. Please spend some time going with me to Van Giang to look for alternatives tomorrow."
Then I became a material supply officer along with Mr. Hanh, going to Van Giang, Ha Dong, and then to Thai Nguyen. Heading for a long business trip within a day to meet the construction deadline, I was even dozing off in the car for a while. I was not an exception among other comrades; both designing and directing construction, and running materials due to urgent schedule requirements give us much pressure on our shoulders. The diversity of electrical materials is indeed a challenge for me.
When designing the backup power supply, the technical requirements were extremely demanding, including military specifications that required a comprehensive knowledge from the technical personnel. This power source necessitated providing sufficient capacity for the whole project, ensuring the smooth operation of large-capacity air conditioning units. The electrical quality (voltage and frequency) must be ensured for the seamless operation of medical equipment. The power source must be highly productive, ensuring continuous consumption for an extended period in case there is a high chance of the U.S assault. Simultaneously, energy savings was taken into account to handle supply disruptions due to damaged bridges. Switching between power sources must be done within a minute, delays are not acceptable due to its unpredicted affect on temperature and humidity of preserving President Ho Chi Minh's body.
Many days of exploration were taken throughout the construction site area, finally we found a place to build the power distribution stations. Going through various scattered records of the Military Equipment Department of the Combat Engineer Headquarters in Thai Nguyen, Lang Son, and Hoa Binh, distribution stations finally had a place. I was keen on reading lots of reference books. Work hard pays off, we got the solutions, satisfying the aforementioned requirements. In fact, the operation at K9 unfolded as the initial assumption predicted, and the power supply system performed admirably.
I chose the Soviet Union's 75kVA transportable diesel power distribution stations, which provided high flexibility, assured capacity, user-friendly operation, automatic speed and power control for steady voltage and frequency. The disadvantage of these stations was that they were difficult to start, especially in the winter mornings. I didn't choose gasoline engines for ease of starting because the High Command's depots didn't have large-capacity gasoline engines at the time. Furthermore, diesel fuel was more cost effective in the long run, and diesel engine spare parts could be found everywhere. Each generator was located in its own underground cavern deep within the hill. All smoke pipes are stretched outside the bunkers and processed using the Hoang Cam Kitchen method, guaranteeing that smoke disperses only beneath the tree canopy. The three generating chambers are dispersed throughout the area in a staggered configuration. Aside from the supporting technical solutions, there is a well-structured operating procedure and intensive operator training. The generator sets are in standby mode, and they must be started for 10 to 20 minutes in advance every morning, ensuring the readiness for use. A battery charging station, a secondary water and acid replenishing space were also constructed.
A small-capacity power generation station, 15kVA was built, with the requirement for machine and fuel efficiency in mind during the winter, in case environment temperatures are low and air conditioning usage is modest, and power demand is low during the nighttime return.
The obligation to ensure non-stop power (no longer than one-minute interruption) was the most difficult and aggravating component for me. An electrical engineer had no trouble designing an automatic backup power circuit. The issue here was that the backup power source was diesel generators. It was challenging to ensure that the generators started fast and stabilized power and voltage within a minute to sustain the load. If the first generator fails to start, the system will automatically switch to the backup generator. Several variables must be considered to ensure immediate generator starts: a strong battery, a hot engine, well-functioning fuel injectors, and preheated diesel. It required a complete solution that combined technical and operational experience. After assembling and trying it several times, it still failed at the timer and switching circuit stages. Unlike the present availability, acquiring a processor with an automatic switching timer is not a problem, back in the days, I had to assemble it using discrete components and experiment extensively. Finally, a circuit that satisfied the specifications was discovered.
The design and installation of the control panel in Control Room 7 were both complicated. The room of keeping President Ho Chi Minh's body was surrounded by 9 alternating air conditioning units, all of Japanese manufacture, with control panels positioned immediately in front of each unit. Operators were not permitted to enter the room with the preserved body to manage the machines, and it was not practicable to shift all control panels to Room 7 due to the extensive wiring, which would jeopardize the system's reliability. The operators seated in the central chamber had to be able to monitor the temperature and humidity in the room containing the preserved body, identify whether to boost or decrease air conditioning, determine which machine is in use, as well as the outdoor temperature and humidity. Operators also kept track of other data such as water quantity, cooling water temperature, and so on. The Soviet medical professionals stood there, shocked yet confident, watching the flashing red and green lights and buzzing sound of the operational self-recording clock. Comprehending creating such a control panel remained challenging for us nowadays still. All of the indicator lights, including the red and green lights, had painted light bulbs. After a period, the paint would wear off and they would need to be repainted or replaced. I also attempted to reduce the supply voltage in order to extend the life of the painted light bulbs. Things were successfully done thanks to the great dedication of Mr. Chieu, Mr. Ba, and the ingenuity of the soldiers of Engineer Brigade 259 of the Engineering Corps; the assistance of the Hanoi medical equipment factory and Workshop X49 of the Combat Engineer Headquarters. What made me super touched was their willingness to disassemble each push button and switch from machine tools, all efforts made for long term preservation of President Ho Chi Minh's body.
The building site has turned to the next chapter, a chapter of urgency, ensuring timely welcome for President Ho Chi Minh's arrival. Workers necessitated the need of working for three continuous shifts, as the completion was far from our expectation. We accompanied side by side, constantly addressing any concerns that arose, very little or zero break-time, resting only when we were extremely exhausted. Everyone appeared thin and sunburned, and even Comrade Cao Dam, lovingly called as "Dam Sua" (the man of milk) due to his super white skin, was now severely tanned. Despite those extreme conditions, everyone was quite healthy.
Our daily routine remained unchanged on numerous projects, yet no one received praise or awards. Even during meetings, it was considered a must-do. Everyone was constantly educated about the importance of responsibility and the great honor of representing the Vietnam People's Army in national security projects. Everyone here was not strange with Deputy Commander Tran Ba Dang's working style. He had been to numerous classified projects and was committed to his profession. The Deputy Commander joked that he was the "king" of construction, air conditioning, power, and water.
On a Sunday morning when the construction site was off, Deputy Commander Tran Ba Dang took great care of us by driving us back to Hanoi for our family reunions. Everyone was truly happy due to its prolonged time away from families. Many carried dried rations and night-shift meal portions were prepared as gifts for their family. As we drove into Son Tay, a UAZ suv from Hanoi stopped over, and the Deputy Commander and Mr. Quyen came out, followed by a military general with a bald forehead. It was my first time meeting General Phung The Tai. Soon after, our car carrying Tai – the Unit officer, Deputy Commander, and Mr. Quyen returned to the construction site without an explanation. We were surprisingly sad, but as soldiers, no emotional expression and complaints are accepted.
Working hard eventually paid off. The night had come to welcome President Ho Chi Minh's arrival. All of the lights around the building site were illuminated in the early evening. The high-pressure lights on both sides were lighted from the drainage ditch at the foot of the hill leading to the peak, generating a bright white streak that circled around the base of the hill and up to the summit, looking quite mystical. All of us were on set, ensuring proper operation of the equipment to welcome President Ho Chi Minh.
Deputy Commander Tran Ba Dang gave me the task of testing several power outage scenarios. He stood next to comrade Le Quang Dao, holding a stopwatch and monitoring the process. I pressed the button to disconnect from the national power system, and the first generator fired up in a matter of seconds. After a few seconds of running, presuming a fault, the second generator started. The national power grid was then restored, and the capacitor-bank switched automatically. "Good job," Deputy Commander said, " the power outage is even unknown for the participants" The convoy carrying President Ho Chi Minh's body arrived at the building site as dawn approached.
I traveled to Hanoi to observe how the lighting system could be utilized for the visit at Ba Dinh Square before designing the lighting system for the visitation. Then I went to Film Studio I at Thuy Khue to see how they lit actors for filming and bought their lights and accessories. The height and scale of Uncle's glass coffin at K9 were impediments to using the Ba Dinh Square lighting system. I created tiny light fixture racks that were mounted on the walls and allowed for far projection. To meet medical regulations, all lights and racks were chrome-plated. Everything was done, but there was no way to test the lighting on a model to determine the angle and color. I was concerned because the adjustment time on President Ho Chi Minh's body was limited to 15 minutes. Recognizing my anxiety, Deputy Commander Tran Ba Dang reported to Unit officer Tai, who was directly in charge of receiving the first-ever visit of Political Bureau members on the anniversary of President Ho Chi Minh's birthday (May 19). Surprisingly, he allowed me to test directly on him. Seeing my hesitation, he asked:
- Why do you still hesitate?
- Certainly, without a glass cover, shining directly on the Unit officer will be extremely hot, and the lights have a high output of up to 1,000W - I honestly admitted.
- Does it get hot as beaming on Nguyen Duc Thuan's head? - He questioned with a smile.
- Sir! Probably not because the lights are placed at a distance of 2m or more! - I explained.
- Let's get ready for tomorrow's trials, and install it as brightly as you can. The day after tomorrow, visitors will come to pay their respects to Uncle Ho. You have no choice but make sure the same quality at the funeral, you will be rewarded mate! - He rubbed my shoulder.
The next day, he lay on the bed with both hands on his abdomen, imitating Uncle Ho's position. When I turned on the lights, bright beams shone on his face. I rapidly altered the focus length and angle. Sweat ran down his brow in a matter of minutes. I was in a rush. It was June, and there was no air conditioning when I was testing. Despite this, he was calm and steady. I instantly adjusted once more. People standing nearby saw that it fit the requirements. I switched off the lights. He stood up. Someone immediately offered him a damp towel, and others used a fan to cool him down.
- How does it look? - He asked everyone.
- It looks nice, sir!
I was about to clean up, suddenly he laid back on the board and demanded, "Let’s try again to make sure it's error-free, Thanh, remember where to shine for Uncle Ho tomorrow."
Everyone agreed when I turned on the lights and adjusted the focal length for a more concentrated light on the face.
As he left the area, his shirt on the back was saturated and lots of sweat could be seen on his brow. I was a bit worried, empathetic, and adored him all at the same time.
I was summoned to Uncle Ho's body room that night. All of the leaders and some Soviet medical professionals attended. I had only 15 minutes to fine-tune the lighting on Uncle Ho's physique for the approval council.
After a while of observing Uncle Ho from behind the glass coffin, I eventually adjusted. I felt like a grandchild returning to see his papa after a long absence. I remembered previous encounters with Uncle Ho. Before we took over the capital at Vai Cay - Thai Nguyen, our construction team built temporary residences for the Central Committee. In the afternoon, I sat and watched Uncle Ho play volleyball with his police guards. He was slimmer and darker back then. The second time was when I introduced the minefield display at the army innovation show on Ly Nam Street. Uncle Ho paid close attention to my talk, clothed in a brown silk suit called Ba Ba and tire sandals. When we went out to the yard, I pushed the handcart to demonstrate the idea of spreading mines with a simple cart. He was chuckling as he continued, "People are about to set the footprint on the moon, and you guys are still using the handcart." Everyone burst out laughing.
This time, witnessing Uncle Ho reclining comfortably as if asleep, with a high and wide forehead and a white beard. I told myself to try the best on adjusting the lighting, making Uncle Ho appear as he was peacefully sleeping. Uncle Ho is a figure of history, a man of easy approach and simplicity.
