Re: [mowbot] Re: Gotta have gas to cut ??

KEN_REED nospam at
Mon, 10 Mar 97 07:15:59 -0700

ken wrote
> >>>I believe the disk is important since it would stir the air less
> >>>than some form of a cross. The air would be churned up by a cross
> >>>always pushing air out of the way, and it moving right back in.
> >>>It's interesting you used the phrase "propeller type arrangement",
> >>>since it would be a zero pitch propeller.
> >>>Note: I haven't experimented with anything but a disk, and I'm
> >>>satisfied enough with it that it is designed into my LawnBot.
> >>>To me it seems intuitive that a disk would cause the least air
> >>>friction losses.

Doug asked:
Did you happen to experiment with the difference between an equally weighted
disc and one with more weight at the outside like a flywheel? I would guess
that a flywheel arrangement might have a higher starting current but
lower run current. If nothing else it would even out the slowdown when
hitting thicker or moist grass patches.

ken replied
Sorry Doug, I've only used an aluminum disk, the thinnest that I thought
would provide the necessary strength. Note that my experiments showed that
pushing air around far out weighed any cutting load. Thus I tried to
minimize the air load.