One assignee leads the ranked field with 456 of the 1,263 records in scope, well ahead of the fifth-ranked filer at 40 records. The top five assignees combined hold 971 records, or 76.9% of all records in scope, which means most new filings in this space are entering a field already dense with prior art from a small number of companies. The ranking itself covers 100 companies total, not just the leaders, so there is a long tail of single- or few-filing entrants below the top ten.

Filings ran from 114 in 2017 to a peak of 119 in 2018, then held roughly steady before easing slightly from 31 records in 2021 to 29 in 2024, a -6% change. That is a mild pull-back rather than a sustained decline. Because patent publication typically lags filing by around 18 months, the 2025-2026 figures in any chart will look artificially low and should not be read as evidence the field is shrinking further.

The largest classes by record count are F02C, gas-turbine plants, at 35.8% of the 1,263 records, and F23R, combustion chambers, at 35.5%, followed by F01D, turbines and non-positive engines, at 34.5%. Aircraft-specific classes such as B64C and B64D cover a smaller share, around 6% and 5% respectively. Since a single record can carry several IPC codes, these percentages add up to well over 100% and each should be compared only against the 1,263-record total, not against one another as slices of a pie.

This Mitsubishi Power filing covers an axial flow compressor where two or more stator vanes are placed downstream of the last rotor blade, with the most-upstream stator vane's blade loading set deliberately lower than a second, further-downstream vane. It is a stage-matching and blade-loading distribution claim aimed at reducing loading stress on the last-stage stator vane during partial-load operation. It does not block axial compressor designs generally; it is specific to that particular loading arrangement across multiple downstream stator vanes, so alternative loading schedules or single-stator-vane configurations sit outside its claim scope.

The core gas-turbine and combustion classes (F02C, F23R, F01D) are heavily filed, but branches like corner-separation control in low-aspect-ratio stators, non-axisymmetric endwall contouring for loss reduction, and incidence-angle tolerance under off-design partial-load conditions show thinner representation relative to that core. These are not zero-filing areas, but they sit well below the density seen in the leading classes, which makes them worth a targeted prior-art search before assuming the space is occupied. Stage-matching for variable-speed operation is a related area worth checking given the corpus's emphasis on fixed-point performance metrics like diffusion factor and polytropic efficiency.