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VonRecktofen

VonRecktofen

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Hi Folks,
I'm trying to get more proficient at accurately simming rockets that I build to include actual individual weights of components and how it will affect the CG and estimated speed and altitude of a particular model that I build. For example:

I'm currently building a 3"fiberglass Madcow Twitch (non dual deployment version, no AV payload bay), and I've downloaded the .rkt file from Madcow's website. How to I "zero out" the estimated weights of the components from the .rkt file and then add in the actual weights of the individual parts to be more accurate? What should I do with the "over ride to mass" and "over ride to CG" boxes? Do I leave them checked or unchecked?

It's a little difficult finding the answers in online users guides, and I thought that I might ask here first!

Thanks for any ideas, suggestions, or links to explanations that might help me to better understand these questions!

Thanks again!
Franz in NJ
 
There is an override tab in the component edit window for each component. With it you can override weight and CG of each component. Or you can build said rocket then override the weight and CG of the whole rocket using the override in the Stage edit window (very top of component tree).
VonRecktofen said:
Hi Folks,
I'm trying to get more proficient at accurately simming rockets that I build to include actual individual weights of components and how it will affect the CG and estimated speed and altitude of a particular model that I build. For example:

I'm currently building a 3"fiberglass Madcow Twitch (non dual deployment version, no AV payload bay), and I've downloaded the .rkt file from Madcow's website. How to I "zero out" the estimated weights of the components from the .rkt file and then add in the actual weights of the individual parts to be more accurate? What should I do with the "over ride to mass" and "over ride to CG" boxes? Do I leave them checked or unchecked?

It's a little difficult finding the answers in online users guides, and I thought that I might ask here first!

Thanks for any ideas, suggestions, or links to explanations that might help me to better understand these questions!

Thanks again!
Franz in NJ
Click to expand...
 
So if I do it the first way you explain it, I should leave the boxes checked and just change (over ride) the weights to those that I measured for each component?
Thanks for the explanation, I remember that you helped me last season with a Madcow MiniBunga sim file....

Thanks again!
Franz in NJ
 
note: you will need to multiply your individual fin weight/mass by the number fins used since the override (for the fins) is for total fin mass.
 
VonRecktofen said:
Got it, thanks!
Click to expand...
For even better accuracy, weigh the whole set of fins, and use that as your override value.

*Usually* you do not override the CG of individual components, just the whole rocket when finished.

Also keep in mind that even with overriding the mass of all your different components, you'll still have some slop factor due to glue and finishing. There is no substitute for empirically determining the weight and CG of the finished rocket, and then overriding the whole mess. But of course you can't do that until after construction is complete.
 
I like to override component mass along the way, then compare vs. the final dry mass. If it's not very close and/or the CG is way off usually it warrants going over everything again, something like a checksum.
 

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