Blade uses several variations of the least squares algorithm. For more information, see "Least Squares Parameters".
This variation performs the standard least squares bestfit algorithm. Flavor file example:
BESTFIT1 LSQ CC CV LE TE
This variation performs the least squares bestfit algorithm where the twist and stack values must not exceed tolerances. Flavor file example:
BESTFIT1 CLSQ CC CV LE TE
In the case where both STACK and RELSTACK values are toleranced, the most constrictive of the two are used to constrain. In the case where DLB (BOW) and STACK calculations are both called for, the DLB tolerances (BOW) are used.
This variation performs the least squares bestfit algorithm that looks at the vectors of the points on the spline for its freedom of "movement". This allows the fit to solve faster than a conventional least squares bestfit. Flavor file example:
BESTFIT1 VECTOR CC CV LE TE
This variation performs the least squares bestfit algorithm that fits all sections at once. Flavor file example:
BESTFIT1 FULLBLADE CC CV LE TE
Leading Edge Arc Least Squares
The leading edge arc least squares fit is a special fit. It swings two arcs from the nose point. All points lying in the annulus defined by the two arcs are used in the bestfit.
If you define LE_RADII parameters, those parameters are used to define the LE radii in the fit.
Flavor file example:
BESTFIT1 LEARC CC TE
The inner arc can have radius of zero so that all points within a circle can be used. This can further be refined by only selecting points on the CVX or CCV side.
Trailing Edge Arc Least Squares
The trailing edge arc least squares fit is a special fit. It swings two arcs from the tail point. All points lying in the annulus defined by the two arcs are used in the bestfit.
If you define TE_RADII parameters, those parameters are used to define the TE radii in the fit.
Flavor file example:
BESTFIT1 TEARC CC TE
The inner arc can have radius of zero so that all points within a circle can be used. This can further be refined by only selecting points on the CVX or CCV side.
Full PC-DMIS Blade Leading Edge Arc
The LE_RADII values that are defined in the Tolerance file for each section create the zones of points that are used in the fit. You have the option to fit points using only the concave side, only the convex side, or both sides. An example is shown below:
Example of defining the full blade leading edge arc