The "T-effect"
Just been reading an article in R & W about a guy (ret'd Test Pilot) flying his Hiller across States. He says that when he was flying across the open desert, he maintained 15' agl to take advantage of the "T-effect".
I can only imagine that it's similar to fixed wing Ground Effect, because he said that he could maintain speed with less power, or fly at a higher speed using the same power.
I've not heard of rotary Ground Effect having any effect at cruising speeds.
Anybody care to elaborate on the "T-effect"?