diff --git a/model/CMakeLists.txt b/model/CMakeLists.txt
index bdac965..72df3c1 100644
--- a/model/CMakeLists.txt
+++ b/model/CMakeLists.txt
@@ -3,6 +3,8 @@ add_library(model
    MotorModel.h
    MotorModelDatabase.cpp
    MotorModelDatabase.h
+   Part.cpp
+   Part.h
    Rocket.cpp
    Rocket.h
    ThrustCurve.cpp
diff --git a/model/MotorModel.cpp b/model/MotorModel.cpp
index 63c393e..a3aecbd 100644
--- a/model/MotorModel.cpp
+++ b/model/MotorModel.cpp
@@ -60,6 +60,7 @@ double MotorModel::getMass(double simTime) const
       double propMassEnd   = i->second;
       double slope = (propMassEnd - propMassStart) / (tEnd - tStart);
       double currentMass = emptyMass + propMassStart + (thrustTime - tStart) * slope;
+      utils::Logger::getInstance()->info("simTime: " + std::to_string(simTime) + ": motor mass: " + std::to_string(currentMass));
       return currentMass;
 
    }
diff --git a/model/Part.cpp b/model/Part.cpp
new file mode 100644
index 0000000..fd3e890
--- /dev/null
+++ b/model/Part.cpp
@@ -0,0 +1,6 @@
+#include "Part.h"
+
+namespace model
+{
+
+} // namespace model
\ No newline at end of file
diff --git a/model/Part.h b/model/Part.h
new file mode 100644
index 0000000..e766fca
--- /dev/null
+++ b/model/Part.h
@@ -0,0 +1,61 @@
+#ifndef MODEL_PART_H
+#define MODEL_PART_H
+
+/// \cond
+// C headers
+// C++ headers
+#include <atomic>
+#include <memory>
+#include <mutex>
+#include <utility>
+
+// 3rd party headers
+/// \endcond
+
+// qtrocket headers
+#include "utils/math/MathTypes.h"
+
+namespace model
+{
+
+class Part
+{
+public:
+   Part();
+   virtual ~Part();
+
+   void setMass(double m) { mass = m; }
+   
+   // Set the inertia tensor
+   void setI(const Matrix3& I) { inertiaTensor = I; }
+   
+   void setCm(const Vector3& x) { cm = x; }
+   // Special version of setCM that assumes the cm lies along the body x-axis
+   void setCm(double x) { cm = {x, 0.0, 0.0}; }
+
+   void setLength(double l) { length = l; }
+
+   void setInnerRadius(double r) { innerRadiusTop = r; innerRadiusBottom = r; }
+   void setOuterRadius(double r) { outerRadiusTop = r; outerRadiusBottom = r; }
+private:
+
+   Matrix3 inertiaTensor; // moment of inertia tensor with respect to the part's center of mass and
+              //
+   double mass; // The moment of inertia tensor also has this, so don't double compute
+
+   Vector3 cm; // center of mass wrt middle of component
+
+   double length;
+   
+   double innerRadiusTop;
+   double outerRadiusTop;
+
+   double innerRadiusBottom;
+   double outerRadiusBottom;
+
+
+};
+
+}
+
+#endif // MODEL_PART_H
\ No newline at end of file
diff --git a/sim/Propagator.h b/sim/Propagator.h
index 2926101..ec7fbe4 100644
--- a/sim/Propagator.h
+++ b/sim/Propagator.h
@@ -59,12 +59,12 @@ private:
    double getForceY();
    double getForceZ();
 
-   double getTorqueP();
-   double getTorqueQ();
-   double getTorqueR();
+   double getTorqueP(); // yaw
+   double getTorqueQ(); // pitch
+   double getTorqueR(); // roll
 
-   double getIpitch() { return 1.0; }
    double getIyaw()   { return 1.0; }
+   double getIpitch() { return 1.0; }
    double getIroll()  { return 1.0; }
 
    std::unique_ptr<sim::RK4Solver<Vector3>> linearIntegrator;
diff --git a/utils/math/MathTypes.h b/utils/math/MathTypes.h
index 9cb354c..9eba8a1 100644
--- a/utils/math/MathTypes.h
+++ b/utils/math/MathTypes.h
@@ -2,6 +2,7 @@
 #define UTILS_MATH_MATHTYPES_H
 
 #include <Eigen/Dense>
+#include <vector>
 
 /// This is not in any namespace. These typedefs are intended to be used throughout QtRocket,
 /// so keeping them in the global namespace seems to make sense.
@@ -20,4 +21,54 @@ using Matrix4 = MyMatrix<4>;
 using Vector3 = MyVector<3>;
 using Vector6 = MyVector<6>;
 
+/*
+namespace utils
+{
+   std::vector<double> myVectorToStdVector(const Vector3& x)
+   {
+      return std::vector<double>{x.coeff(0), x.coeff(1), x.coeff(2)};
+   }
+
+   std::vector<double> myVectorToStdVector(const Vector6& x)
+   {
+      return std::vector<double>{x.coeff(0),
+                                 x.coeff(1),
+                                 x.coeff(2),
+                                 x.coeff(3),
+                                 x.coeff(4),
+                                 x.coeff(5)};
+   }
+}
+
+class Vector3 : public MyVector<3>
+{
+public:
+   template<typename... Args>
+   Vector3(Args&&... args) : MyVector<3>(std::forward<Args>(args)...)
+   {}
+   operator std::vector<double>()
+   {
+      return std::vector<double>{this->coeff(0), this->coeff(1), this->coeff(2)};
+   }
+};
+
+class Vector6 : public MyVector<6>
+{
+public:
+   template<typename... Args>
+   Vector6(Args&&... args) : MyVector<6>(std::forward<Args>(args)...)
+   {}
+   operator std::vector<double>()
+   {
+      return std::vector<double>{this->coeff(0),
+                                 this->coeff(1),
+                                 this->coeff(2),
+                                 this->coeff(3),
+                                 this->coeff(4),
+                                 this->coeff(5)};
+   }
+};
+*/
+
+
 #endif // UTILS_MATH_MATHTYPES_H
\ No newline at end of file