Most alarming sound I've heard was x2 Ospreys flying extremely low.

I was out for a run with headphones on made me stop in my tracks and pull out earbuds.

Nothing sounds like a Huey.

Here’s a quick story to illustrate how fast and impressive the old Super Stallion is. I once crewed a CH-53E out to North Carolina for rework. They gave us three days to get there. In seven and a half hours of flight time we flew from El Toro, CA to Oklahoma City.

By the end of day 2 we were in Pensacola, FL with a slight delay in Alexandria Louisiana to fix a hydraulic leak. Our max allowable cruising airspeed was 160 knots. With the tailwinds, the GPS was tracking us at 210. So from CA to FL in less than 16 hours of flight time in a helicopter.

We could fly for 4 hours before stopping for gas and when topped off carried 16,000 pounds of fuel.

We always had to fly real slow for the 46’s and the Hueys.

Yes, I miss that job.
Tony.

Military rotor blades are also designed to be able to take multiple hits from small ADA cannon rounds. Different materials and construction, different sounds.

Military aircraft have the same blade construction as their civil counterparts. Same parts.

Someone noted that civil aircraft are lighter, which isn't true; civil aircraft are typically the same or heavier, depending on the mission.

I'm guessing a Bell Jet Ranger flown by the military or by a corporate pilot sound the same.