| 1938 JOHN CANETTA Variable Load Brake Patent |
| 1938 POUR L AVIAT SOC ET Variable Pitch Airscrew |
| 1938 WESTINGHOUSE AIR BRAKE CO Variable Load Brake |
| 1938 CHARLES Variable Incidence Wing Airplanes |
| 1938 BARNHART Variable Action Tubular Shaft Art |
| 1938 PAUL Variable Pitch Airscrew Patent Print |
| 1938 BOYD Automatic Variable Pitch Propeller Art |
| 1938 MILDRED M REID Variable Pitch Propeller Art |
| 1938 REID Variable Pitch Propeller Patent Print |
| 1938 MANFRED Variable Pitch Propeller Aircraft |
| 1938 GALLAGHER Reverse Variable Pitch Propeller |
| 1938 EDOUARD Airscrew Having A Variable Pitch |
| 1938 LILLEY Automatic Variable Pitch Propeller |
| 1938 EVERTS Variable Pitch Propeller Patent |
| 1938 RCA CORP Variable Acoustical Reverberation System |
| 1938 SMITH Variable Pitch Propeller Patent Print |
| 1938 BENDIX AVIAT CORP Variable Pitch Propeller |
| 1938 EVEREL PROPELLER CORP Variable Pitch Propeller |
| 1938 BURGESS Variable Camber Wing Aircraft Art |
| 1938 ARTHUR Variable Acoustical Reverberation System |
| 1938 BRUNO Variable Pitch Propeller Patent Print |
| 1938 ALLRED Variable Pitch Propeller Airplanes Like |
| 1938 LAWIEY Variable Controllable Pitch Airscrew |