[hpv-boats] Right Angle Drive

[Bobby Ray]

Thanks for the tips on the angle grinders.  I knew that dead ones must be
useful for something!

On Thu, Aug 12, 2010 at 4:20 PM, Tony Nelson <onetonpump at gmail.com> wrote:

> Rick Willoughby <rickwill at ...> writes:
>
> >
> > There are a few manufacturers of angle drives.  Mitrpak are possibly
> > the best value.
> > http://www.mitrpak.com/product_datasheet.php?product_id=34
> >
> > The best size prop will be spun at 4 to 5 times cadence.  You can use
> > a large diameter prop turned at 2 to 3 time cadence directly from a
> > gearbox but the box costs quite a lot.
> >
> > You can also use twisted chain drives.
> >
> > You can pair two boxes with 1:2 steep up to get combined 1:4 but this
> > ends up very expensive.
> >
> > There is a thread on this forum that has a huge amount of detail with
> > photos if you care to wade through it:
> > http://www.boatdesign.net/forums/boat-design/pedal-powered-
> > boats-23345.html
> >
> > Rick Willoughby
> > rickwill at ...
> >
> >
>
>
> No-Worries:: the gearboxes suitable for adapting to "Human-Power" are
> plentiful. cheap [free], rugged, but not marinised.
> Angle-grinders provide them, burnt motors with smoothly run-in gears ; I've
> gutted about 20 of them, they are usually 3 to 4 to one, common makita is
> 3.3,which I find optimum. The highest ratio I've found is a 9::1, but that
> was 'stripped'
> The'trick' is to make an adaptor for fitting a cluster [I use 14-18 tooth]
> onto the shaft where the disc was [maybe remove the ratchet mechanism] ;
> struggle & fight to remove the rotor windings; cut this motor-shaft short &
> make a coupling [about 9mm id]
> For a pp boat, have the chainwheel on the right side of a 'crankshaft; so
> the
> chain passes behind the operator to a cluster [enabling variable ratios]- a
> shaft across to the centre-line, where the g/b increases speed / changes
> direction / feeds aft to the prop-shaft. via a seal & universal-joint.
> Use a bigger chainwheel for higher RPM output.
> Ok so I made one  -almo0st - figured a better solution - I'll tell you when
> I
> have it!
> Surfing on the Bare island Bombora in a pp-Kayak on Botany Bay in Oz; watch
> me
> go!
> Tony Nelson.
>
>
>
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