Original poster: "Bob (R.A.) Jones" <a1accounting@xxxxxxxxxxxxx>
Sorry again Terry for this off subject post.
> Robert,
>
> My Marinov motor runs better than 2000 RPM, which is over 33 revolutions
> per second. Do you really think what you are describing can take place
> that fast in steel? Especially the cooling and shrinking part.
>
> Ed Wingate RATCB
>
Wow Ed I am impressed by the RPM.
As to if I really think my description can take place.
I assume your trying to appeal to my feelings and every day experiences.
But since you ask. I have read no other detailed explanation. So it would
get my vote until I do read an other detailed explanation.
As to the speed of shrinking and expansion I will give it an analytical go
for you.
Thermal time constants are determined by the thermal mass and thermal
resistance.
I have direct experience of heating the surface of a thick steel plate with
a blow torch. I would estimate the time constant of the hot spot to be say
10 seconds and say one inch in diameter.
Now consider a hot spot just 1/1000 inch in diameter i.e. the contact point
of a bearing.
The thermal mass is 1000,000,000 times less. What about the thermal
resistance. The surface area will have decreased by 1000,000 times but the
length will have gone down by 1000 times.
So the thermal time constant would be 10ms. Compared to 33RPS this is in
the correct range. This is the cooling time lag.
The heating time lag would be determined by the thermal mass, thermal
resistance and input energy.
Given the small mass of the contact point I would expect that to be ms too
but I am guessing.
I better analysis would be a moving contact point were the conditions are
quasi static with continuous thermal flows .
The next step in the normal way physics is investigated would be to
construct a model and compare it to measurements then make predictions.
Perhaps the maximum speed could be determined for different materials then
confirmed by experiment for example.
Perhaps the time constant of a small spot can be directly measured too.
Robert (R. A.) Jones
A1 Accounting, Inc., Fl
407 649 6400