Hello Contributors,

Gadge, that's great information about BP Zoom. It will probably find
itself in the History Forum with a BP Zoom brochure at some point.
It's good historical stuff. Thank you.

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Gizmo seems in agreement with MrMckay about the Imperial:
that it's clutch was not amenable to slippage, and the ground-speed was
too fast. I think that's sort-off right.

I know this topic needs to be flushed out and expanded, but I want to
articulate the basis for what I think about this in draft here.

Ground speed - These high ground speeds seem to be part of the
design philosophy dating back to 1902. Historically, the advertising
suggests that it was a boast and a feature to have a quick speed.

Why?: the two historical reasons were labour costs and fuel costs.
Power mowers were beyond the reach of most folks early 20th Century.
If you had a power mower, the servant would operate it.
As an example, Atco advertising for their Standard machines would
boast how much fuel would be used for X area of lawn, and how much
lawn area could be mowed in Y amount of time. It appears to me that
the argument was never primarily about operator comfort.

Given that most power reel mowers arriving here were of British origin, we inherited
that design concept in Australia, even though we had a less-rigid class system.

Clutches - The Imperial's primary clutch is a small centrifugal one.
The small shoes require significant RPM to engage the drive. This exacerbated
the transmission ratios. Other machines - like the Ransomes - had much larger
centrifugal clutches that were engaged at lower RPMs.

The second issue is the landroll clutch itself. My argument here is that
lawnmower designers followed the design philosophy from automotive practice -
One 'let the clutch out' to engage drive. Slipping the clutch was frowned
upon, because the mechanism would 'burn out'.

The Imperial's plate clutch has a pressure plate using 3 strong springs.
This inhibits sensitive feeling of the clutch hand control. The operator is
encouraged to just use the clutch as an on-off switch. Ridiculous!
The Imperial, again, exacerbates the problem by the un-ergonomic position
of the lever and the rotary-style handlebars. The first Imperials had a
much better handle bar of Ransome's design.

I am trying to solve a riddle about who first thought of reversing the
notion of 'letting the clutch out' to 'letting the clutch in' on lawnmowers.
This has made all the difference to operator comfort on machines like
Scott Bonnar's 45. That 'hair-trigger' clutch still uses plates (like
the Imperial) but the clutch is 'let in' by sensitive hand inputs. It's
variable speed clutch will happily slip all day. What company first used
the hair-trigger clutch? Most likely not Scott Bonnar.

In summary, it's not transmission ratios that make the Imperial a bit awkward
for some. Although, Personally, I love reel mowers where I can use just enough RPM
to do the job at a leisurely pace. A quick pace is not good for me.

The Imperial uses a combination of two types of clutches that, through their
particular designs, take away from the enjoyment of turning grass into lawn.

All very interesting.
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JACK.