ISTM that the whole tip jet idea was simply not a success. Not only loud, but an ear busting frequency. Offhand, does anyone know of any tip jet copters that went into service?
Actually they fix the noise issue, only around 90 decibels by the time the program was canceled, not much higher then a regular helicopter and the flow and landed the "Y" in the middle of London and got zero complaints before the noise reduction messers, it was noise that killed the rotodyne, it was the government not willing to spend 10,000,000 to finish the project despite haveing already spent 26,000,000 already (aka every British aero space project that was canceled between 1945 and 1970).