wrote in message
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I never said anything about tip mach number. I said "rotor speed".
The two are similar, but not the same.

Your original quote was "By increasing the rotor speed to just under the
speed
of sound,..." . When you talk about "rotor speed" and the "speed of sound"
in the same sentence, blade tip Mach number is the only rational way to
connect these two. How else can anyone compare "rotor speed" with the
"speed of sound", please tell us. Without my connecting these two
quantities this way for you, everything you said is completely meaningless
(as opposed to simply wrong).

I'm not going to sit here and
argue with an anonymous person who thinks a "diskCopter" is practical.

I've NEVER said anything about the "diskCopter" at all in this discusssion.
(For the record I think the "diskCopter" is silly.)

Your facts about ground resonance may have been accurate 50 years ago,
but they are out of date.


We're talking about physics here, what part of that "went out of date".
Please tell us what part of the analysis "no longer applies". I'll bet you
don't even really know what ground resonance is. How about this, tell the
group just what is in resonance with what. What is the frequency of the
blade motions, what is the frequency of the body motions? How is it
prevented? Do you know the FAA or military requirements with respect to
ground resonance? Tell us how many helicopters you have done a real
stability analysis for. When you can do this, then please explain further
your comments about the "speed of sound" and it's crucial role in this
phenomenom, I'd really like to hear your detailed analysis.

I really don't care about what you know and don't know, I just get a little
annoyed with people on the internet who spout complete nonsense to the rest
of the world, and then rather than trying to learn something argue with
reality. You might mislead someone with your nonsense and cause some harm
some day. I'm sorry if tone of this conversation is less than polite, I
just don't deal well with nonsense.