Lu,
Yes, I have flown an aircraft where the controls could not be moved until the rotor rpm increased enough to power up the hydraulics. The military AS-330J is like this; it has a fully articulated head and no elastomerics.
This aircraft was originally designed and supplied with a disconnect in the No. 1 engine input, to allow the engine to run the No. 1 hydraulic system and No. 1 AC generator for ground servicing (these were / are primarily AC aircraft with the generators running off the main gearbox accessories). However, the "disconnect" facility was modded out of our fleet as they could slip in flight. I seem to remember if this happened the No.1 hydraulics and the No. 1 AC generator would go off line, but more importantly, the (only) MGB oil pump would stop as well, which took the shine off your day.
On these aircraft, if a single hydraulic failure occurred, the aircraft would be put down asap for obvious reasons. I spent a few occasions in fields waiting for hydraulic repairs during my time operating them.
However, it is academic only whether the cyclic becomes rigid or thrashes round the cockpit following a complete hydraulic failure. You cannot control the aircraft in either case. A joke we used to make was that in the unfortunate event of a total hydraulic failure the pilot's immediate actions would be to unstrap, drop trousers, sit on the cyclic. Just to give the BOI something to think about!
Another nasty problem with these aircraft was that if one of the two separate tail rotor servo control "pull" cables snapped, the servo would run to full travel the opposite way. This would result in either full positive or full negative T/R pitch, which rendered the aircraft uncontrollable in yaw. I know for sure that the RAF fleet flew like this for over twenty years but I understand they now have been modded with a centering device for the servo valve which gives some level of control, like later Sikorsky designs.
And then there was the engine response (Turmo 3C4) which was appalling from flight idle, due to the lack of a collective anticipator in the FCU design...
You are correct about the lack of certification for civilian use. There were many mods and additions to the civil version.
Edit: If we are going to continue discussing this we perhaps ought to start a new thread on Rotorheads as I feel we have diverted from Purplehaze's original line of discussion. Sorry, PH!
[This message has been edited by ShyTorque (edited 09 January 2001).]