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Rocksim/OpenRocket question on overriding weight/CG for assemblies

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NateLowrie

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So, I have a rocket and it's fully assembled. I need to adjust the design file for the actual weight of the rocket for simulation purposes. So, I weigh the fin can as a whole and balance to find the CG. This is due to wanted to factor in the epoxy weight and anything else that might have been missed weighing just the components. Same thing with the Av-Bay and nose cone.

My questions:
  • In Rocksim and/or OpenRocket, is there an easier way of overriding the mass of the whole assembly without zeroing out the calculated mass of each sub component?
  • Is this generally a good idea, or should I be going another route like adding a mass object to tweak the final weight/CG of the sub-assembly?
  • My current thought is that weighing each sub-assembly is preferable to weighing the whole rocket. Is that the preferred practice? Or do you like exact weighing each component?
 

smugglervt

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I prefer to weigh and balance my rockets after the build is complete and all recovery hardware and electronics are included. Then override the mass and CG at the very top of the Openrocket design window which is usually shown as the stage or sustainer component.
 

NateLowrie

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I prefer to weigh and balance my rockets after the build is complete and all recovery hardware and electronics are included. Then override the mass and CG at the very top of the Openrocket design window which is usually shown as the stage or sustainer component.
That would be extremely useful. I did not know that was a feature. Could you provide a screenshot?
 

djkingsley

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You can also, do the same thing for any group of components. So if you fin can is finished just override the fin can weight and cg. Then later override other components until you have the fully decked out rockets weight and cg. You do not have to zero out the mass properties of the sub-parts.
 

markkoelsch

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I weigh each component and all adhesives. I modify the sim as I go. The i weigh it before paint and find the cg. I then paint it and check weight and Cg. I add a mass at Cg for the paint.
 
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