diff --git a/src/fieldSources/basicSource/rotorDiskSource/rotorDiskSource.C b/src/fieldSources/basicSource/rotorDiskSource/rotorDiskSource.C
index c3f042fe0160277a4773b46da6f4b334259e2e41..82ecd711765222b191bbcbbd8a68b033b4e1e454 100644
--- a/src/fieldSources/basicSource/rotorDiskSource/rotorDiskSource.C
+++ b/src/fieldSources/basicSource/rotorDiskSource/rotorDiskSource.C
@@ -369,7 +369,7 @@ void Foam::rotorDiskSource::constructGeometry()
 
             // blade flap angle [radians]
             scalar beta =
-                flap_.beta0 - flap_.beta1*cos(psi) - flap_.beta2*sin(psi);
+                flap_.beta0 - flap_.beta1c*cos(psi) - flap_.beta2s*sin(psi);
 
             // determine rotation tensor to convert from planar system into the
             // rotor cone system
@@ -659,8 +659,8 @@ bool Foam::rotorDiskSource::read(const dictionary& dict)
 
         const dictionary& flapCoeffs(coeffs_.subDict("flapCoeffs"));
         flapCoeffs.lookup("beta0") >> flap_.beta0;
-        flapCoeffs.lookup("beta1") >> flap_.beta1;
-        flapCoeffs.lookup("beta2") >> flap_.beta2;
+        flapCoeffs.lookup("beta1c") >> flap_.beta1c;
+        flapCoeffs.lookup("beta2s") >> flap_.beta2s;
         flap_.beta0 = degToRad(flap_.beta0);
         flap_.beta1 = degToRad(flap_.beta1);
         flap_.beta2 = degToRad(flap_.beta2);
diff --git a/src/fieldSources/basicSource/rotorDiskSource/rotorDiskSource.H b/src/fieldSources/basicSource/rotorDiskSource/rotorDiskSource.H
index 7fd7d33964602b8574da194ff178eb882b546445..17deb44816be960353e83e5b8ee118ab68adb92d 100644
--- a/src/fieldSources/basicSource/rotorDiskSource/rotorDiskSource.H
+++ b/src/fieldSources/basicSource/rotorDiskSource/rotorDiskSource.H
@@ -51,8 +51,8 @@ Description
             flapCoeffs
             {
                 beta0           0;  // coning angle [deg]
-                beta1           0;  // lateral flapping coeff
-                beta2           0;  // longitudinal flapping coeff
+                beta1c          0;  // lateral flapping coeff (cos coeff)
+                beta2s          0;  // longitudinal flapping coeff (sin coeff)
             }
 
             blade
@@ -78,7 +78,6 @@ Description
             local         : use local flow conditions
 
 
-
 SourceFiles
     rotorDiskSource.C
     rotorDiskSourceTemplates.C
@@ -138,8 +137,8 @@ protected:
         struct flapData
         {
             scalar beta0;   // coning angle
-            scalar beta1;   // lateral flapping coeff
-            scalar beta2;   // longitudinal flapping coeff
+            scalar beta1c;  // lateral flapping coeff (cos coeff)
+            scalar beta2s;  // longitudinal flapping coeff (sin coeff)
         };
 
 
@@ -148,7 +147,7 @@ protected:
         //- Name of density field
         word rhoName_;
 
-        //- Reference density if rhoName = 'none'
+        //- Reference density for rhoName = 'none'
         scalar rhoRef_;
 
         //- Rotational speed [rad/s]
@@ -254,6 +253,9 @@ public:
 
         // Access
 
+            //- Return the reference density for rhoName = 'none'
+            inline scalar rhoRef() const;
+
             //- Return the rotational speed [rad/s]
             //  Positive anti-clockwise when looking along -ve lift direction
             inline scalar omega() const;
diff --git a/src/fieldSources/basicSource/rotorDiskSource/rotorDiskSourceI.H b/src/fieldSources/basicSource/rotorDiskSource/rotorDiskSourceI.H
index 7c194e8713e4beb538292f9e2fd3a6f1c44a9ed5..9d095e846b9d3343bcef811a3301de304ac034fa 100644
--- a/src/fieldSources/basicSource/rotorDiskSource/rotorDiskSourceI.H
+++ b/src/fieldSources/basicSource/rotorDiskSource/rotorDiskSourceI.H
@@ -27,11 +27,18 @@ License
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
+Foam::scalar Foam::rotorDiskSource::rhoRef() const
+{
+    return rhoRef_;
+}
+
+
 Foam::scalar Foam::rotorDiskSource::omega() const
 {
     return omega_;
 }
 
+
 const Foam::List<Foam::point>& Foam::rotorDiskSource::x() const
 {
     return x_;