diff --git a/blast/mdao/opti_NACA.py b/blast/mdao/opti_NACA.py
index 88c185dbf756eb45152684eba0d56ac71544e1e6..066587298448ffe8b1eb3f2a6f94a3dec5c4bde1 100644
--- a/blast/mdao/opti_NACA.py
+++ b/blast/mdao/opti_NACA.py
@@ -76,7 +76,7 @@ def cfgInviscid(nthrds, verb):
 def cfgBlast(verb):
     return {
         'Re' : 1e7,                 # Freestream Reynolds number
-        'Minf' : 0.2,               # Freestream Mach number (used for the computation of the time step only)
+        'Minf' : 0.1,               # Freestream Mach number (used for the computation of the time step only)
         'CFL0' : 1.,                 # Inital CFL number of the calculation
         'Verb': verb,               # Verbosity level of the solver
         'couplIter': 50,            # Maximum number of iterations