America's First Stealth Helicopter - The Quiet One

Helicopters are typically not known as discreet machines. Their roaring turbine exhaust, whining overhead blades, and buzzing tail rotors can usually be heard from miles away. Yet, at the height of the Vietnam War, the CIA decided that only the versatility of a helicopter would allow them to pull-off one of the most famous top-secret wiretapping operations to ever take place in enemy territory. In response to the mission plans, the Defense Advanced Research Projects Agency, or DARPA, was left to figure out what many considered impogmssible - how to create a stealth helicopter.
Orders were sent to the Aircraft Division of the Hughes Tool Company to take on the project, codenamed “Mainstreet.” Tested at Area 51, the program would create two copies of a special purpose helicopter, the Hughes 500P. Their target would be a phone line deep within North Vietnam. It was a mission that would truly test if the helicopter was deserving of its nickname - the Quiet One...