The Allison T40 is considered to be a pioneer of turboprop engines. Comprised of two T38's , the engine was highly unreliable and dangerous. Many lessons were learned from early designs and eventually this lead to a redundant T56.

Sources & Credits:

Excellent Breakdown of TurboProps
https://www.youtube.com/watch?v=0XRhCwk7XzU&t=793s

https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195689/allison-t40/

T56 Engine Run
https://www.youtube.com/watch?v=3rqlQxHXji0
https://www.youtube.com/watch?v=IdvFB-ePs0g

https://www.youtube.com/watch?v=YMNzebi50LU (C-2)

https://www.northropgrumman.com/what-we-do/air/e-2d-advanced-hawkeye/

Music:
"Abstract Background" From Envato
"No Time To Die" From CO.AG MUSIC
https://www.youtube.com/channel/UCcavSftXHgxLBWwLDm_bNvA

By: Tech Planet
Title: Allison T40 - The MOST POWERFUL Engine Of It's TIME
Sourced From: www.youtube.com/watch?v=vLHqJO3_Gvg