11-03-2013, 09:18 AM
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NAR Lifetime Member
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Join Date: Jul 2009
Location: In a state of confidence
Posts: 266
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Quote:
Originally Posted by rtuinila
Hi Folks,
I have a question about the Cp location on just a plain body tube. I would have thought the Cp of a body tube would be at the mid-point of the tube at the same location as the Cg. But when I put a body tube into a new sustainer design in Rocksim the Cp is at the extreme end of the tube. Is that right or is my Rocksim Cp calculator broken? Thanks!
Roy
PS What brought this on was I downloaded a Rocsim file of the Estes Pathfinder and when I opened it the Cp marker was located at the tip of the nose cone
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RocSim uses modified Barrowman equations to determine the CP location. People must remember that the Barrowman equations were themselves simplified equations derieved from more complex equations of aerodynamics. The Barrowman equations were based on the rocket having a nose cone, body tube and fins to function. If one of these parts is missing then the CP location cannot be confediently determined with great accuracy.
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