| 1950 VINCENT MULVANEY Rotor Helicopters Art |
| 1950 ALLEN Retractable Lift Rotor Mechanism Aircraft |
| 1950 AMERICAN STEEL FOUNDRIES Rotor Brake Patent |
| 1950 BROUWER Rotor Rotor Sustained Aircraft Art |
| 1950 CAMPBELL Aircraft Rotor Damping Art Print |
| 1950 TACK CARL Rotor Brake Patent Print Art |
| 1950 FIRESTONE TIRE RUBBER CO Aircraft Rotor Damping |
| 1950 MCDONALD Helicopter Rotor Arrangement Art |
| 1950 UNITED AIRCRAFT CORP Rotor Support Patent |
| 1950 SIKORSKY IGOR Rotor Support Patent Print |
| 1950 AVERY Sustaining Rotor Rotating Wing Aircraft |
| 1950 AMERICAN STEEL FOUNDRIES Rotor Type Railway Brake |
| 1950 MCYERS Lifting Rotor Blade Attachment Art |
| 1950 HUNT Two Bladed Tail Rotor On Common Hinge |
| 1950 WEIR Rotor For Helicopters Patent Print Art |
| 1950 RUDOLPH Inverse Rotor Art |
| 1950 RUDOLPH MATHEISEL Inverse Rotor Patent |
| 1950 GILBERT W MAGILL Rotor Rotor Sustained Aircraft |
| 1950 RANSON Rotor Blade For Helicopters Patent |
| 1950 SIKORSKY Helicopter Rotor Control Mechanism |
| 1950 PIASECKI Tandem Rotor Helicopter Patent |
| 1950 PERRY Rotor Mounting For Helicopters Patent |
| 1950 HELSTEN Rotor Type Railway Brake Patent |
| 1950 MILLER Forward Rotor Transmission Helicopters |