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If you get off the train at JR Kokubunji Station, go down the stairs from the North exit, and then walk on the road along the train track toward Shinjuku for a while, you'll find the Waseda Jitsugyo Middle School. In 1955, the ground at this school was the ruins of Shinchuo Kougyo's factory. Mr. Genji Harajima (91), who currently lives in Kokubunji, recalls the launch:
I was watching the launch of the rockets for about 2 hours from 7-8 meters away from the site. The pencil-shaped objects flew horizontally against the targets made from shoji paper with a sound like steam and were very fast. Amongst the rockets were ones that couldn't reach the targets and had fallen down in front of them. I heard a conversation among the group saying something like, "The rockets flew very well, so let's set the launch pad further back." I remember the scene where they measured the distance from the launch pad to the target. The people in the group were saying that they had wanted to shoot the rockets at an earlier date, but they couldn't find a suitable place. (Harajima)
Shinchuo Kougyo used to produce guns called "Nanbu" at this Kokubunji factory. Thus they had a test-firing pit there. In the end of February 1955, Hideo Itokawa visited this pit along with Yasuaki Toda and a younger researcher from his laboratory named Iwao Yoshiyama. They looked around several concrete buildings and took an interest in one of them. Iwao Yoshiyama tried to find a power supply for a high-speed camera and fortunately found a three-phase 200V power supply, but he couldn't tell if it was dead or alive. The three men decided to reinvestigate the power supply later and left the factory. For a long time after that, Yoshiyama recalled images of green grass showing their faces around the future test launch site.
On March 11, 1955, the first horizontal test launch was performed using this pit and on April 12, a public launch test was performed in front of related people from ministries and the media.
The Pencil rocket was launched horizontally from a 1.5-m-long launcher (launch pad) and broke through the thin wire screens one after another before landing in the sand pit on the other side. The speed variations of the rockets were measured by the time difference that the pencil rockets cut through the lead wires using an oscillograph. The orbit and spin of the rockets were measured from the location and direction on the trace of the tail wings on the screens. Basic data including speed, acceleration, and trajectory changes using a different centroid and tail wing shape was obtained for the full-scale flight test with the assistance of the high-speed camera.
These horizontal test launches were performed on April 12, 13, 14, 18, 19 and 23 and all 29 rockets flew successfully. These Pencil rockets carried 13g propellants (or half the amount, 6.5g) with about a 30kg thrust, approximately 0.1 seconds burning time, and three different angles of tail wing torsions (0 degrees, 2.5 degrees and 5 degrees.) Three types of materials -- steel, brass and Geralmine (Aluminum alloy) -- were used for the head and the fuselage of the rocket's body. The center of gravity was also changeable back and forth using three positions.
The rocket reached a maximum speed about 5 meters after launch, which was about 110 to 140 meters per second. Although these rockets were launched horizontally in a half-submerged trench, the busy Chuo line train tracks lay just over a nearby concrete wall, so group members sat on the wall and stopped counting down for launches when trains passed by.
This horizontal launch of the Pencil rocket was selected as one of the 10 top news topics of 1955 by the Ministry of Education.
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Inside the little body of a Pencil rocket, packed full of our Japanese future belongings for space.
In 1992, 37 years after the historic launch of the Pencil rocket, the Institute of Space and Astronautical Science (ISAS) received good news: "A model of the Pencil rocket is going to be exhibited at the Smithsonian National Air and Space Museum in Washington D.C." The ISAS soon sent a replica of the Pencil rocket to the Smithsonian Museum, but there was a long waiting list for space technology to be exhibited and we had to be patient for news of the dates of the Pencil rocket exhibition. Today, in the corner of the "History of Space Flight" section, the Pencil rocket stands in an elegant case amongst the other exhibited objects. As a cute little Japanese symbol, it has become a popular exhibit for many children who like to have there photo taken next to it.
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