diff --git a/Engine/prop30FP2B.xml b/Engine/prop30FP2B.xml
index f2712ceae..a9293ebdd 100644
--- a/Engine/prop30FP2B.xml
+++ b/Engine/prop30FP2B.xml
@@ -3,6 +3,24 @@
   IXX       5
   DIAMETER  76
   NUMBLADES  2
+  EFFICIENCY 17 1
+  0.0   0.00
+  0.1   0.09
+  0.2   0.16
+  0.3   0.25
+  0.4   0.34
+  0.5   0.42
+  0.6   0.52
+  0.7   0.64
+  0.8   0.73
+  0.9   0.79
+  1.0   0.83
+  1.1   0.85
+  1.2   0.86
+  1.3   0.85
+  1.4   0.80
+  1.5   0.50
+  1.55  0.00
   C_THRUST 17 1
   0.0   0.117
   0.1   0.117
diff --git a/Engine/prop_generic2f.xml b/Engine/prop_generic2f.xml
index 87afe3e2a..2e4ec6a5d 100644
--- a/Engine/prop_generic2f.xml
+++ b/Engine/prop_generic2f.xml
@@ -3,6 +3,19 @@
   IXX       5
   DIAMETER  76
   NUMBLADES  2
+  EFFICIENCY 12 1
+  0.0   0.00
+  0.1   0.08
+  0.2   0.33
+  0.3   0.50
+  0.4   0.61
+  0.5   0.70
+  0.6   0.76
+  0.7   0.83
+  0.8   0.85
+  0.9   0.84
+  1.0   0.64
+  1.04  0.00
   C_THRUST 12 1
   0.0   0.104
   0.1   0.103