Wildman Rocketry Giveaway!


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  1. #1

    New RockSim Engine Database

    Apogee Components has updated the RockSim engine database to include every certified rocket motor on the NAR/CAR/TRA combined list of approved motors. This new database is in the RASP.eng format, allowing it to be used in any software program that supports this common engine format.

    There are over 363 motors in the new database, compared to approximately 250 in the old data files. The database even includes many new motors that were certified after the NAR/CAR/TRA list was released in mid-2004.

    This extensive motor database allows modelers using a simulation program (like RockSim) to pre-test their rockets with even more motor choices than before. Knowing how rockets will perform prior to launching them increases their safety and reliabilty. Because it reduces the chances of an expensive mishap, performing a preflight simulation saves modelers money.

    The free data file can be downloaded from the Apogee Components web site at: http://www.apogeerockets.com/Adding_motors.asp

    -----------
    You are welcome to pass on this information to the newsletter editor of your local rocketry club.


  2. #2
    Thanks Tim.


  3. #3
    Join Date
    18th January 2009
    Location
    Maryland
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    9,446
    Outstanding! So the Aerotech announcement was only the tip of the o' iceberg!
    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  4. #4
    I appreciate the new motor files Tim. Downloaded great and now I am ready with up-to-date motor information.

  5. #5

    Re: New RockSim Engine Database

    Originally posted by Apogee
    Apogee Components has updated the RockSim engine database to include every certified rocket motor on the NAR/CAR/TRA combined list of approved motors. This new database is in the RASP.eng format, allowing it to be used in any software program that supports this common engine format.
    Tim-

    The file you created cannot be used AS-IS by wRasp... the manufacturer names are WAY too long. Four characters max.

    Nice job, otherwise.

  6. #6
    Join Date
    18th January 2009
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    More encouragement to get Rsim
    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  7. #7
    Originally posted by rstaff3
    More encouragement to get Rsim
    Rocksim, in its' current incarnation, won't allow me to back-track predicted and actual altitudes, in order to get real Cd values. Lowly as it is, wRasp w/DigiTrack does that for me.

  8. #8
    Join Date
    18th January 2009
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    My point is that difference may be intentional.

    So what exactly is the process you are using?
    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  9. #9
    Join Date
    23rd January 2009
    Location
    San Tan Valley, AZ
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    251
    Without just telling me I should buy RockSIM (I already know I should buy it, but just don't have the cash right now), is there anyway to compile these new engine files for the demo version?

  10. #10
    Originally posted by rstaff3
    My point is that difference may be intentional.
    Could be.

    So what exactly is the process you are using?
    Well... first I do my designs on RockSim. I try to be as detailed as I can, to get the CG as accurate as possible. Once I get done 'glassing the parts, I do a weight-and-balance on each, and use the part-specific mass override to reflect the info. Once it's all assembled, I do a weight-and-balance on the whole thing... I find that the RockSim CG can be a half-caliber or more off - even with actual values. Then I'll pick some motors and do the sims, getting estimated altitudes.

    Next, I go to wRasp, and input my creations' info for weight, diameter, and use the 'default' Cd. I'll pick the same motors I used in RockSim, and do the same sims. Then I'll do a flight with one of the motors I chose to sim, and take the altimeter data as the 'real' apogee for that motor. Entering that value into the DigiTrack 'BackTrack' screen in wRasp, I can derive the actual Cd value to use in future sims of the same rocket.

    Takes a while... but I like to know just how high my cameras are going. Plus, it helps me choose a motor that won't do any waiver-busting on me...

  11. #11
    Originally posted by LFLekx
    Rocksim, in its' current incarnation, won't allow me to back-track predicted and actual altitudes, in order to get real Cd values. Lowly as it is, wRasp w/DigiTrack does that for me.
    http://apogeerockets.com/smartsim.asp

    Use it to backtrack Cd or any other variable in RockSim. Performs univariate optimization, too.

    Ken

  12. #12
    Join Date
    18th January 2009
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    Originally posted by LFLekx
    Could be.



    Well... first I do my designs on RockSim. I try to be as detailed as I can, to get the CG as accurate as possible. Once I get done 'glassing the parts, I do a weight-and-balance on each, and use the part-specific mass override to reflect the info. Once it's all assembled, I do a weight-and-balance on the whole thing... I find that the RockSim CG can be a half-caliber or more off - even with actual values. Then I'll pick some motors and do the sims, getting estimated altitudes.

    Next, I go to wRasp, and input my creations' info for weight, diameter, and use the 'default' Cd. I'll pick the same motors I used in RockSim, and do the same sims. Then I'll do a flight with one of the motors I chose to sim, and take the altimeter data as the 'real' apogee for that motor. Entering that value into the DigiTrack 'BackTrack' screen in wRasp, I can derive the actual Cd value to use in future sims of the same rocket.

    Takes a while... but I like to know just how high my cameras are going. Plus, it helps me choose a motor that won't do any waiver-busting on me...
    Thanks for outlining the process for me
    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  13. #13
    Originally posted by rocket72175
    http://apogeerockets.com/smartsim.asp

    Use it to backtrack Cd or any other variable in RockSim. Performs univariate optimization, too.

    Ken
    Something for my wish-list, then...

  14. #14
    Originally posted by rstaff3
    Thanks for outlining the process for me
    No prob. Happy to share my tricks. (My failures... that's another story. )

  15. #15

    Re: New RockSim Engine Database

    Originally posted by Apogee
    Apogee Components has updated the RockSim engine database to include every certified rocket motor on the NAR/CAR/TRA combined list of approved motors. This new database is in the RASP.eng format, allowing it to be used in any software program that supports this common engine format.
    Some of the eng files do not load in the Engine Editor, namely Aerotech.eng and kosdon.eng. A file format error occurs. Upon further inspection, these files contain UNIX line terminators (you can see this in Notepad).

    To fix the problem, open the files in Wordpad and save the file again. This now puts PC line terminators on the files and Engine Editor will read them. Rocksim reads them in either fashion.

    Ken

  16. #16
    Join Date
    18th January 2009
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    They seemed to work for me. Originally the Aerotech file had an wRASP error that I caught, but it was quickly fixed. I wonder if there is yet another new version?

    OOPS, I stand corrected. They compiled but you couldn't edit them. Thanks for the fix!

    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

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