RSE File

Introduction

Also called "RockSim XML format" and using an '.rse" extension, these files are used to describe a motor for loading into Rocksim and OpenRocket.

RockSim v8 uses either the RASP or the new RockSim XML format (.rse). The .rse format can store extra information about the motors, such as the type of engine it is (single-use, reloadable, hybrid).

For more information about entering motor information into Rocksim, please also read the FAQ entry: [1]

XML Tags

Engine Tag Attributes

Boolean values are represented by either the integer 1 for true or the integer 0 for false. Note that all attributes, including numbers, must be passed in as strings (in quotation marks). If the motor file is poorly formatted (values are missing or incorrect), OpenRocket will not display them in the motor menu, and the error message can only be viewed in the Debug Log under Help.

• mfg: String = Manufacturer
• code: String = Motor Designation (e.g. "F128-6")
• Type: String = Motor Classification; one of : ("single-use" | "hybrid" | "reloadable" ) Other values are accepted, but not recognized.
• dia: Number (millimeters) = Diameter
• len: Number (millimeters) = Length

• initWt: Number (grams) = Initial Weight
• propWt: Number (grams) = Propellant Weight

• delays: Number (milliseconds?) = Motor ejection delay times. Optional list of comma separated numbers

• auto-calc-mass: Number (boolean) = Should automatically calculate the change in mass of the motor over the burn time. The mass is calculated from the thrust curve by assuming a constant exhaust velocity (mass decrease is proportional to thrust).
• auto-calc-cg: Number (boolean) = Should automatically calculate center of gravity. The CG is assumed to be located at the center of the motor casing

Not Used by OpenRocket

OpenRocket can read these files without many of the available options. I suspect that EngEdit automatically calculates them for you, but they are not necessary for OpenRocket simulations.

• massFrac: Number = Mass Fraction. OpenRocket always recalculates with (initWt - propWt) / initWt
• Isp: Number (seconds) = [Specific Impulse](https://wiki.openrocket.info/List_of_useful_custom_expressions#Specific_impulse_.28Isp.29)
• Itot: Number (Newton-seconds) = Total Impulse
• burn-time: Number (seconds) = Burn Time
• avgThrust: Number (Newtons) = Average Thrust
• peakThrust: Number (Newtons) = Maximum Thrust

• throatDia: Number (Millimeters?) = Nozzle Throat Diameter
• exitDia: Number (Millimeters?) = Nozzle Exit Diameter

• tDiv = "10"
• tStep = "-1."
• tFix = "1"
• FDiv = "10"
• FStep = "-1."
• FFix = "1"
• mDiv = "10"
• mStep = "-1."
• mFix = "1"
• cgDiv = "10"
• cgStep = "-1."
• cgFix = "1"

Engine Tag Children

• comments

String. Text Description

• data

A list of "eng-data" tags. Together this list will define the thrust curve (and other properties which change over time).

eng-data Tag Attributes

• t: Number (seconds) = Time
• f: Number (Newtons) = Force of thrust
• m: Number (grams) = Total motor mass. Instantly overrides the initWt header, but there is no verification that they are identical
• cg: Number (millimeters) = Center of gravity of the entire motor, measured from the leading edge of the motor

Example File

<engine-database>
  <engine-list>
    <engine FDiv="10" FFix="1" FStep="-1." Isp="195.96" Itot="39.78" Type="reloadable" auto-calc-cg="1" auto-calc-mass="1"
    avgThrust="18.082" burn-time="2.2" cgDiv="10" cgFix="1" cgStep="-1." code="E18" delays="4,8" dia="24." exitDia="0." initWt="57." 
    len="70." mDiv="10" mFix="1" mStep="-1." massFrac="36.32" mfg="Aerotech" peakThrust="31." propWt="20.7" tDiv="10" tFix="1" 
    tStep="-1." throatDia="0.">
      <data>
        <eng-data cg="35." f="0." m="20.7" t="0."/>
        <eng-data cg="35." f="31." m="20.3774" t="0.04"/>
        <eng-data cg="35." f="30." m="14.6638" t="0.4"/>
        <eng-data cg="35." f="26.7" m="8.7629" t="0.8"/>
        <eng-data cg="35." f="19.1" m="3.99638" t="1.2"/>
        <eng-data cg="35." f="8." m="1.17602" t="1.6"/>
        <eng-data cg="35." f="2.2" m="0.11448" t="2."/>
        <eng-data cg="35." f="0." m="0." t="2.2"/>
      </data>
    </engine>
  </engine-list>
</engine-database>