JohnDixson asks:
1. What aircraft reactions accompanied those instances where they actually encountered vortex ring state?
2. In any of the actual vortex ring state events, was the effect of prop pitch increase evaluated?
Hi John,
Your first question has been discussed on this thread on occasion and as JeffG suggested, the best source for more firsthand information is in the AHS papers he mentioned:
-V-22 Low-Speed/High Rate of Descent (HROD) Test Results
-V-22 High Rate of Descent (HROD) Test Procedures and Long Record Analysis
Regarding your second question, a non-manufacturer source familiar with the trials mentioned:
Prop pitch is not even a remote issue here. Tiltrotors use beta governors - unlike an engine governor on say, a UH-1. Just like a turboprop airplane, as you add power, the prop pitch changes to maintain the set rpm. Once you command helicopter mode within the conversion corridor, the rpm is ramped up automatically to helo mode rpm and there it remains governed and constant. At low power in the descent, the rpm still remains constant and the blade pitch has been increased by the governor, naturally.
Hope that helps,
21stC