Interestingly while the AH-56 had problems with high speed flight rotor stability and flutter issues, they were not insurmountable and fixes were in the works
Jack Real agree on this fact. Problems of rotor stability had been cured after 1969 crashes.
In fact they had found three solutions to this problem!
- an improved variant of the original rotor (interim solution)
- a new rotor with a mecanical control
- another solution was electronic control
(I'm not specialist, I've to check the article).
In fact from 1971 there was no problems with the rotor... the machine reached
447 kph (after a 4300 hp engine was mounted). Long flights at 370 kph and treetops were made.
Seems that the program was definitevely buried after a demo "failed" : one TOW missile (over 10!) missed its target at Yuma in front of Army officials. This was used as pretext. ..