Yamamoto thought over his own words. "I will do my best for the recovery of Hiroshima." He thought of that day when he promised not to give up. Yamamoto assembled the 47 engineers and said. "I'll do everything in my power for this engine. That's the rotary spirit. Will you follow me even if the project fails?" All the engineers said yes. (Male)
We invite Messrs. Hiroshi Ozeki and Kazuo Takada of the 47 engineers to the studio. Mr. Takada, I have heard that in your family there are A-bomb survivors.
My mother and elder brother are survivors. We lost our home. The family members and relatives of many people in Hiroshima were exposed to the radiation. I wanted to help the recovery of the devastated Hiroshima by developing the rotary engine, which had been a dream for a long time.
Toyo Kogyo had just entered the four wheel market at that time. What did you think when you heard about the development the rotary engine for the first time?
Everything was new to me because I was a new employee at that time.
The rotary engine had not been successfully developed for mass-production, had it?
This project was so huge that if we failed the development, the company would be seriously affected.
There were various problems such as the "Click-clack Mountain." Mr. Takada, you discovered the countermeasure for "charter marks." didn't you?
Who named it first?
I am not sure, but the problem seemed to be fatal and we were afraid that we wouldn't be able to solve it. So, I think that's why we called it "chatter marks (devil's scratch)."
Lets take a look at the "chatter marks," This is a sample with no marks. We can't see any scratches here.
The finish is smooth.
This is another sample. There are lateral scratches here.
Importation was liberalised in 1963. Many American automobiles were unloaded at Yokohama Bay. That year, the car industry was shocked at other news. The merger of Nissan and Prince Automobile was planned by MITI. The reorganisation of the industry accelerated. According to rumour Toyota would absorb Toyo Kogyo soon. The company had been the centre of Hiroshima's recovery since the day it was transformed into a first aid station. The 47 young engineers would decide the fate of the company. The vehicle body for the rotary engine was also being developed. Young designers designed a beautiful exterior of the vehicle that no one had ever seen before. Low height and a smooth line. The design made the most of the features of the rotary engine - small and high powered. (Kuroda)
I was truly happy. The moment I saw the vehicle body, I thought that I would develop the engine installed in the vehicle at any expense.
They wanted to install the dream engine in the vehicle. Yasuo Tatsutomi thought out an unexpected solution. His hobby was magic.
Magic is contrary to common sense. People tend to be bound by common sense. For example, here is a 100-yen coin, and it disappears. Another coin appears.
Tatsutomi thought out an amazing solution that would prevent oil leakage with rubber. Everybody however thought little of his idea, because they thought that rubber would melt due to the high engine temperature inside the engine. Tatsutomi coercively put a rubber seal on and started the engine. The rubber didn't melt and no oil leakage was observed. The temperature inside the engine was lower than expected. His desperate efforts had solved the problem.
The hardest problem was the "chatter marks" that formed sharp scratches inside. Scratches from the frictional vibration were observed at the apex of the rotor. If the apex seals were too hard, they would scar. If they were too soft, the rotor would be worn out. Five hundred materials were tested.
One day Yamamoto tested carbon that was used as the lead in pencils. Although it was so smooth that it had no scratches, the intensity was not enough. Jun Miyata, who joined the company two years before, tried to mix strong metal such as iron with carbon so as to increase the intensity, but he failed. Then he came up with an idea that a weak metal such as aluminium could be mixed with carbon. He tried.
To be honest, I was surprised. As I knew the intensity of aluminium and carbon, I could guess the intensity of mixed material. But the intensity of mixed material was much stronger than I first imagined.
The test drive started in front of the project members. After 100,000 kms, no "chatter marks" were identified. Together with excited members, Yamamoto, who had devoted himself to the project, had a smile all over his face.