Lynn, Thanks for the info Bud. As for the 205, the tail rotors were swapped over on it also in 1972 when the USAF Bought their HH-1H version of the UH-1H. That became the newer 205 civilian models. The US Army being stubborn, kept the lower speeds even though the actual data showed that 124 Kts and 6400 was the best cruise speed and no limiting loads were placed on the new tailrotor. Finally I initiated the Manual changes when I got called to flight evaluation board at Ft. Hood as an expert witness for a Lt. Hacker who was accused of exceeding limits in flight and scaring the hell out of his Lt. Co-Pilot. Hacker got off and I submitted the data to AVSCOM and told them their lack of action was causing grief in the field. After that, they bit the bullet and got money to change the fleet and the manuals.
BTW, for your info, the best RPM for the main rotor is at the 5800 RPM engine mark,(but rotor efficiency falls off dramatically at the 5500 ERPM mark) that's why you sometimes flew out of LZs successfully with low RPM. The Best tailrotor efficiency is around the 6750 ERPM mark but that raises hell with the engine limits. So the 6600 RPM that we flew was a compromise number for engine, MR and TR. I don't know if you were ever taught maneuver g as part of your training but the MR of the UH-1H had a max of 18000 pounds of thrust, so if you had a 9000 pound aircraft the most it could pull was 2 gs and after that you had to lose airspeed or altitude to sustain a g level above 2. That is why, on occasion, a young aviator drove them into the ground when he tried to turn at low level with a heavy load. Remember the angle of bank can and does determine the G load when flown in trim. On my second tour I taught maneuver G to the 101st division and later I think it became a part of flight school training and the day of yank and bank was past. Anyway thanks for tweeking me. It gave my brain (what's left of it) some exercise.
Salute
BT