12095
The initial plan was to launch the aircraft vertically , but this concept was later changed to a conventional horizontal take-off from a tricycle-wheeled trolley , similar to that used by the first eight prototypes of the Arado Ar 234 jet reconnaissance bomber .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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