For Robert and Gardner have a look.
http://www.microhyd
The only web link that came to mind for other models when Robert
mentioned reverse stems. Models do 35-40mph true spreed not scale
with a 12$ brushed motor long time ago. I also have a micro r/c
airplane that I designed and built that does 95mph true speed caught
on radar with an all up weight of 7.5 onces with a brushless 100watt
motor with an under 10 amp draw. My web site is down at the moment.
Just a small rant. Micro why, least amount of weight, least amount
of power for the fastest most efficient speeds, all in the name of
balance balance balance.... No balance no GO.
Todd
--- In harryproa@yahoogrou
wrote:
>
> This is what I have been rabbiting on about for years.It is nice to
> see it in practice. Once the bows start to immerse, there may be
even
> less resistance. Compare this to a flared bow which would have a
> sudden increase in resistance. Another thing I advocate is a
reverse
> stem to make it smoother through chop. Could you get someone to
push a
> board up and down in the water to see how the boats go through
waves.
> My ideal lw hull shape is a bit of a flare at the crossbeam, going
to
> vertical half way to the bow and slightly reversing as it gets to
the
> bow. I am not sure how easy it would be to do as I don't know how
much
> twist can be put into the sheets used for skinning the craft This
> would give more bury for the crossbeams, a slightly wider berth
and a
> bit of lift in surfing conditions, while having good wave piercing
> ability. Optimising the bows is made more difficult as they are
also
> the stern but I think a v just near the end would help with coming
off
> waves, allow some waterplane resistance, and allow a fine exit.
> The gradual burying is much easier to handle than cartwheeling a
Hobie 16
> --- In harryproa@yahoogrou
> >
> > I did a static test a while back in the tube with the old lwh
and
> > weight. I think what kept the model upright was the righting
moment
> > vs heeling angle and extra buoyancy in reverse sheer in lwh when
> > wind pressure spilled from the sail at an angle less than the
> > heeling angle to cause an over turn.
> >
> > The fact that the hulls are square they due have a high
prismatic
> > coefficient. lwh is .801 . So I think this helps to maintain
drive
> > even when submerged along with the reverse sheer adding buoyancy
> > gradually the deeper the bow goes under. Could be wrong here
but
> > seems that in combination of the two, high coefficient and
reverse
> > sheer. The water pressure or forces on hull are small and
gradual
> > nothing drastic or extreme to cuase sudden change in effect, to
a
> > point. Probably way off on how it works but with the right
> > intention.
> >
> > Todd
> >
> > --- In harryproa@yahoogrou
> > wrote:
> > >
> > > -most impressed by how boat kept on sailing with bow
submerged, and
> > > then there was point where there wasn't enough weight on the
> > stern to
> > > keep it down. Still trying to work out why it didn't capsize
but
> > > stalled and fell back to start again -- In
> > > harryproa@yahoogrou
> > > >
> > > > http://www.youtube.
> > > > http://www.youtube.
> > > >
> > > > Same day test with square harry full sails and main alone,
along
> > with
> > > > crab claw model.
> > > >
> > > > New board on square harry has a more positive feed back not
> > becoming
> > > > over powered and stalling seems to hook up well even with
the
> > larger
> > > > sail area. You can see though in the puffs the bow gets over
> > powered.
> > > > But when reduced to main sail alone in stronger winds it
> > balances back
> > > > with probably more board pressure. Don't see full sail
working
> > in
> > > > anything over 8mph. I would reef main by 1/3 first or reef
> > foresail by
> > > > 1/3 and main by half, second. I thnik maybe instead of
185sq''
> > better
> > > > would be 150sqft on a shorter stick 0n square harry.
> > > >
> > > > Todd
> > > >
> > >
> >
>
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