Re: HydroDynamic Lifting

Bill Atkinson wrote:
snip
> The plane's weight IS in the direction of the vertical reference; the
> two vectors are parallel.  Perhaps the diagram could be clearer.
>>

oops!
I see now which line the vertical reference is referring to.

> Yes, "but quicker". With no (or very small) drag (as with a very
> narrow blade) one would have to pull through very rapidly to generate
> some particular and significant reaction force.  BUT, this SAME
> reaction force could be attained with any other "blade" depending only
> on the pull-through speed. Theoretically all blades can produce any
> given propulsive force, the only difference between them being their
> slip (hydrodynamic) characteristic which, as we see, has nothing to do
> with the force attained.
>

That is interesting.
We had a discussion here relatively recently about "rigging to stature", and
I questioned whether decreasing not just the gearing, but the blade (spoon)
size for a smaller rower was sensible, thus enabling a narrow span and
therefore acieve the severe catch angles of those blessed with great height.

It seems bizarre to me that an elderly lightweight woman sculler uses the
same size blade (spoon) as Rob Wadell.

The topic turned to DIY adjustment of blades. Ewoud chimed in that he has
had some sucess decreasing the spoon size in this way with some of his
athletes.

CD took a different line, he said that small people should just accept
rowing short, thus accepting loss of lift, but instead go for bigger blades
still to minimise their "slippy stroke".

Any comments Bill?

> Thanks for your thorough interest.
> Bill

you're welcome... thanks for a great site.