Open Fan Jet Engine Technology

Plenty of upsides, and some downsides come to mind:

1/ If a blade snaps on a normal engine, the metal casing catches it. With an open fan, that broken blade turns into shrapnel flying straight toward the passengers, fuel tanks, etc.

2/ The blades would be huge. You can’t just hang them under the wing of a normal Boeing 737 or Airbus A320.

3/ The metal casing on a normal engine acts like a giant muffler. Open rotors are loud.

4/ Open blades have no protection from bird strikes, hailstorms, or runway debris.