Charles Gray wrote:

Also, isn't a tilt-rotor considerably less effecient than a

helicopter in vertical flight?

Yes

You dont get something for nothing. Tiltrotors have extreamly high disk

loading which makes hover performance very poor.

John Roncallo

But then...what do you consider Vertical "Flight"? A V-22 Osprey or any
other tilt rotor ie. Bell or Kawasaki weren't developed for Vertical
"Flight". They were developed to get to their approximate destinations at
fixed wing speeds. In commercial applications this would allow for them to
fly in a commercial traffic arrival pattern (as toward a major airport and
then "break out" to transition to a heliport. In military applications they
could get to a destination at fixed wing speeds and then transition in and
out of a "LZ" pick up or deploy personnel or cargo. Comparing them to
helicopters is apples and oranges.