hammer velocity

[Delwin D. Fandrich]

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  ----- Original Message -----=20
  From: Richard Brekne=20
  To: Pianotech=20
  Sent: Tuesday, April 29, 2003 12:07 AM
  Subject: Re: hammer velocity


   =20
  Hence the querrie I made about the "left over" force that could =
possibly cause an accelleration of the hammer after the actual and =
direct force of the key has been removed.=20

  After several posts I think we all have gotten the point that there =
has to be a force to accelerate/deaccelerate and object. Yet none of =
these have really addressed the origional query satisfactorilly, tho a =
couple have mentioned lightly the below.=20

  What I'd be curious to know,  is if and when the flexing of action =
parts can cause such an acceleration.=20

At no point, except, possibly, very light pianissimo, is the link =
between key and hammer as direct as we traditionally like to assume. =
There is nearly always a certain amount of bending and twisting going =
on. During this process it is possible that it could be contributing to =
some acceleration somewhere at some specific time. But I wouldn't count =
on it.=20

The only quick answer I can think of to your question goes back to the =
varying time lag between the start of key motion and the end of hammer =
motion. This time lag exists because of the bending and compressing of =
the various action components. If we were somehow able to use these =
bending motions to accelerate the hammer to some faster velocity than =
would otherwise be possible, it seems to me we should then be able to =
arrange for the hammer to impact the string sooner than it otherwise =
would without this bending and flexing. I.e., the bending motion would =
accelerate the hammer faster and it would travel faster than would be =
the case with a perfectly rigid action. Carrying this to its logical =
conclusion then, with a compliant action we should be able to get the =
hammer to impact the strings somewhat before we strike the key. Nice =
trick if only we could get it.

I think it is possible--probable--that the bending and flexing motion of =
various action components--particularly that of the hammershank--can and =
does cause the velocity and the motion of the hammer to vary. =
Unfortunately, this is in no way controllable. And, I think, but have =
not proven, that the velocity of a real-world hammer will always be =
somewhat less than it would be with a perfectly rigid action.

Del




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