fix(polar): CLslope calc when polar for single Re

CHANGELOG.md

@@ -18,6 +18,8 @@ to [Semantic Versioning][sem_ver].
 ### Fixed
 - Issue with zero lift angle calculation when polars provided for a single
   Reynolds
+- Issue with lift curve slope calculation when polars provided for a single
+  Reynolds
 
 ## [0.1.1] - 2023-02-13
 

RELEASE.md

@@ -10,3 +10,5 @@ automatically generated and do not contain all dependencies.
 This release features:
 - **FIX**: Issue with zero lift angle calculation when polars provided for a
   single Reynolds
+- **FIX**: Issue with lift curve slope calculation when polars provided for a
+  single Reynolds

src/solvers/leishman.m

@@ -133,10 +133,14 @@ function clSlope = getclslope(Af, iAf, reynolds)
     clSlope = zeros(size(iAf));
 
     for i = 1:length(Af)
-        clSlope(iAf == i) = interp1(Af(i).Polar.reynolds, ...
-                                    Af(i).Polar.Lin.slope, ...
-                                    reynolds(iAf == i), ...
-                                    'linear', 'extrap');
+        if numel(Af(i).Polar.reynolds) == 1
+            clSlope(iAf == i) = Af(i).Polar.Lin.slope;
+        else
+            clSlope(iAf == i) = interp1(Af(i).Polar.reynolds, ...
+                                        Af(i).Polar.Lin.slope, ...
+                                        reynolds(iAf == i), ...
+                                        'linear', 'extrap');
+        end
     end
 
 end