Finding high-quality, long-duration helicopter sound effects can be tricky since many stock libraries focus on short clips. For a solid 5-minute experience, you can use these verified sources for continuous flying and ambient sounds.
If you can't find a single 5-minute file that fits your specific needs, download a high-quality 30-second loop from Storyblocks or Pixabay and duplicate it in any free editor like Audacity to reach your desired length. Helicopter Flight (75 Minutes) - SoundCloud
A massive library of specific helicopter types (Huey, Apache, etc.) for more realistic or "solid" sound design.
If you need much more than 5 minutes for background ambience or sleep, this 75-minute recording on SoundCloud offers a deep, immersive flying drone.
You can find extended clips like a 5-minute, 29-second recording of a helicopter landing with cockpit radio on HookSounds .
Great for high-fidelity, curated flying and hovering sounds.
Pixabay Music hosts a 16-minute "Helicopter Flight recorded from inside" for a first-person perspective. Quick Download Sites (Royalty-Free)