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Mandel Lenkowsky Early Vertical Flight Development Collection, 1936-1946


Collection Item Summary:

This collection includes notebooks containing scientific notes and mathematical calculations, a random assortment of journals and periodicals, published reference books, a few advertising and promotional brochures all pertaining to American experimental, military and commercial vertical flight from the late 1930s to the late 1940s. The collection also contains photographs of the following helicopters: Sikorsky XR-1, XR-4, YR-4, XR-5, XR-6, XR-6A, VS-300; Kellet XO-60 and XO-61; and Rotachute P-4. Also included are photographs of helicopters by Pitcarin, Landgraf, Greyhound Bus, Spratt, Berliner, Ochmichen, and DeBothezat.

Collection Item Long Description:


  • Helicopters
  • Aeronautics, Military--Research
  • Aeronautics, Military
  • Aeronautics, Commercial
  • Aeronautics
  • Helicopters--Flight testing
  • Sikorsky (USA) XR-4
  • Sikorsky (USA) XR-5
  • Sikorsky (USA) XR-6
  • Sikorsky (USA) XR-6A
  • Sikorsky (USA) VS-300 Family
  • Kellet XO-60 Autogiro
  • Kellet XO-61 Autogiro
  • Sikorsky (USA) R-6 (H-6) Family
  • Sikorsky (USA) R-4 (H-4) Family
  • Periodicals

Data Source

National Air and Space Museum Archives


No restrictions on access


Lenkowsky, Mandel

Physical description

2.18 cubic feet (2 records center boxes)


  • 1936
  • 1936-1946


Mandel Lenkowsky, a civil aeronautical engineer, was involved with the United States Army in the early development of the helicopter.


  • Photographs
  • Collection descriptions
  • Publications
  • Notebooks

Local number


Finding Aids

Online Finding Aid