G�day
Max and all
The dialectic of friendly discussion is so important to how
ODK functions
and offers an alternative to other social media forms. Max, you are always
thorough and polite.
My initial interest in grass cutting efficiency arose when I was employed as a
tradie in a large lawnmower firm. We were selling a lot of top-end North American
machines � Gravely, Simplicity, Dixon and Yazoo. The first issue we noticed was
that these machines could not cut low enough for Aussie preferences.
We cut low here!
Simple solutions were modifying the height adjuster. The problem there was that,
inevitably, the mower skirt would interfere with the desire to cut lower. It would drag
on the ground.
So, I started modifying the cutter heads � with longer shafts. This did the trick and
made customers very happy. But there was a problem. The blade height extended
below the shallow skirts used on many USA lawnmowers. There was a
safety issue.It was at this point I realised that
skirt height was an
equal player in chute and
catcher design. If the skirt height was too shallow, good luck with arch and catcher design.
I guess it depends on exactly what two mowers you are comparing, we were talking
about Victa so I compared Victa bases of the same time period.
Max, I totally agree. The only major AUS domestic lawnmower maker of the 1960s and 1970s
to
not adopt a high arch design was
Pope. Pope stuck with its high-skirted, but mid-arched,
pressed-steel bases to the end. Max, you are right, I moved beyond Victa for the comments I made.
But compare the skirt height of a
Pope base to a
Victa of the day.
I find that a bad analogy for a high arch mower because when you restrict the
flow of a garden hose yes you get an increase in velocity but your flow rate is halved,
Yep, the science is indisputable. My argument is one of balance and outcome �
between skirt height, arch design and catcher design. Max, you know catcher venting
is also part of this story. My analogy is not that bad.
A final word on the Victa Vortex. I have argued here that the joint venture �
between Victa and the CSIRO � was about reducing noise, not cutting efficiency.
Cutting efficiency was no better than equal to previous designs.
Max, I feel we have more in common than disagreement. You are right: we need to
be more specific in comparing apples with apples. But the big three must be
skirt height,
chute design and
catcher design. I hope I got that right.
-----------------------------
Jack
