Hello Mark,
Tested some today with my models traditional against eql Aframe
Dyna. Post a clip In nonharry file.
You know when you shunt you must scrub off apparent wind slowing
down to a stop eventually. Which should be addressed when learning
to sail a shunting craft. Or suffer the conseqences, damage to the
boat or people on board. The apperent wind is the power of the rig
with out foward drive there is no power for over turning the craft.
The righting moment of float along with weight to windward and the
cant of sail to windward all work in favor of keeping the craft up
right, to with stand gusts to a point. Another aspect of the Aframe
rig is the fine tuning adjustments, gust control. So you want to
shunt you pinch high to slow srubbing off apparent wind your not a
beam to the wind. Easing the Aframe back from most foward position
with the same AoA set on sail when A frame reaches center of hull
the AoA of sail will be in a non drive or stalled position. The
boat and sail are parrellel with wind. No chance of being blown over
except maybe from a wind sheer or instant gust hits you from a beam
most boats can go over then. I'm not saying I have all the bugs
worked out but with the rigid sail and adjustments the A frame
offers, the bugs should be easily worked out. Also knowing how it
works and sailing it how it should be sailed is somthing to think
about too. Sure would be a sweet looking futuristic harry for sure.
Why not push it to the max seems ashame to put the same old rig
we've seen for ever on such an extreme looking craft. But hey thats
just my opinion.
Steering,I'm not saying you wouldn't have steering. The steering
would be on the windward hull not the dagger board. The sweeping
dagger board would be in the leeward hull.
Todd
--- In harryproa@yahoogrou
wrote:
>
> Todd,
>
> I'm having a hard time picturing the rig with a center spar going
> neutral through a shunt.
>
> At 90 degrees to the wind, in the middle of the shunt, the rig
would
> produce no lift, but would present a large amount of sail area.
In big
> winds, this could present problems. While having X square meters
sail
> up could be safe when using lift to drive the boat, the same sail
area
> could be enough to quickly capsize the boat when presented dead on
to
> the wind.
>
> But I might be missing something here.
>
> I'm glad you're experimenting with this because dynarig-like
sails
> could be quite a gift, provided the details get worked out.
>
> ---
>
> I agree with Rob in that it's crucial to have the ability to
steer
> when flying a hull. I don't mind seeing dagger boards in windward
> hulls, which beneficially allow the boat to slide more as the hull
> rises, but steering is a different thing. The crew need every
method
> possible at their disposal to dump wind and/or avoid obstacles when
> sailing on the edge.
>
> - Mike
>
>
>
> Todd wrote:
> >
> > Sorry for stepping on toes. I deleted my files . Just want to put
> > them up briefly to get some feed back thanks.
> >
> > I have heard about the bolger rig causing some problems but think
> > its more of inexperience issue (taking the time to figure out
how to
> > use the rig) than the rig itself. I think with the wing ribs
solidly
> > attached to center spar allowing the entire sail to rotate
> > uniformily will allow better control. On the model when shunting
the
> > rig passes through a nuetral area midship producing no lift or
> > driving force until nudged foward or sail is trimmed with leading
> > edge in just a bit. Working on a less complicated reefing system
> > than like on the Maltese Falcon. Also experimenting with setting
AOA
> > of wing to a neutral position and just moving A frame alone
adding
> > positive or nagetive Angle of attack, having seperate adjustments
> > for triming sail for fine tuning and not having sheets or lines
at
> > all.
> >
> > Hopfully building the movable A frame. The rig strength and
weight
> > will be relative to building the same strength into a single none
> > stayed mast. Although the forces are distributed through mast,
> > frame , base, and stays working as one united the diameters of
frame
> > will be smaller. So extreme beefi'ness and unwanted weight might
> > not be needed. If not than drag may be a concern. Weight of the
rig
> > is some what centralized and distributed between the two hulls
for
> > and aft and side to side so weight is not concentrated in one
> > location. I don't see weight being an issue. Except for extreme
over
> > building. But yet to be determined. Going to build a 16footer
using
> > a hull I have already for the leeward float. If the new reefing
rig
> > idea works.
> >
> > Still curious as to what happens when boards are pulled up on El
> > when sailing?
> >
> > Todd
> >
> > --- In harryproa@yahoogrou
> > <mailto:harryproa%
wrote:
> > >
> > > Steering is crucial as the sheet may be jammed or cleated. Some
> > of the ideas on the ww steering boat are not mine. When the owner
> > is ready, we will let you know.
> > >
> > > The Dynawing looks cool, but would be hard to shunt in a big
> > breeze. These rigs have been tried on proas (Bolger rig, AYRS
rig)
> > but shunting in a breeze always ends the experiment. With a
> > movable fore and aft rig, the steering and leeway resistance can
be
> > anywhere. However, the beefing up required for a rig that is
> > movable will be more than if it is stationery. Controlling it
full
> > size may also be a problem.
> > >
> > > regards,
> > >
> > > Rob
> > > ----- Original Message -----
> > > From: Todd
> > > To: harryproa@yahoogrou
> > <mailto:harryproa%
> > > Sent: Sunday, April 15, 2007 2:26 AM
> > > Subject: [harryproa] Re: Rudders on lee hull only
> > >
> > >
> > > I don't really see how steering is crucial when flying a hull.
> > When
> > > I think about when a hull flys and the points of sail that it
> > would
> > > most likely happen, steering could end in catastrophe. With
> > proper
> > > balance when hull flys the boat shouldn't change course so
> > > drastically and just settle with a eased sheet. Just my thought
> > > anyway.
> > >
> > > I'm going to test the kick up rudders on windward hull rear
down
> > > front up and sweeping dagger board on middle of lee hull with
> > model
> > > just to see if its feasible.
> > >
> > > Tell us what your windward steering is on your new drawing .
> > Come
> > > on share, Whats with the holding back:)
> > >
> > > Todd
> > >
> > >
> > > -- In harryproa@yahoogrou
> > <mailto:harryproa%
wrote:
> > > >
> > > > G'day,
> > > >
> > > > El is the test bed and it flies a hull. So may the big ones,
> > and
> > > if they do, steerage is critical. The ratios for weight to
> > windward
> > > vary, and you are right, it is not a major concern. They work
> > very
> > > well where they are, so at this stage I have not seen the need
> > to
> > > experiment with athwartships location.
> > > >
> > > > regards,
> > > >
> > > > Rob
> > > > ----- Original Message -----
> > > > From: Todd
> > > > To: harryproa@yahoogrou
> > <mailto:harryproa%
> > > > Sent: Friday, April 13, 2007 1:03 PM
> > > > Subject: [harryproa] Re: Rudders on lee hull only
> > > >
> > > >
> > > >
> > > >
> > > > I was thinking your elementary was your test bed for the
> > larger
> > > > boats. Which I thought were not designed to fly windward
hull.
> > > What
> > > > are your ratio's for weight to windward I must be
> > > misunderstanding
> > > > your concept.
> > > >
> > > > I was curious since the trimarans would normally load leeward
> > > float
> > > > along with main hull and have the main steering on the main
> > hull
> > > yes
> > > > I know they do have smaller stearing blades on the floats.
> > Since
> > > > your bigger boats don't fly windward hulls and have a similar
> > > load
> > > > to what the tri has, curious to find out if it would have
same
> > > input
> > > > characteristics having main steering appendages on a shorter
> > > loaded
> > > > windward hull.
> > > >
> > > > I'm finding out with the eql model that it is more weight
> > > sensitive
> > > > with weight placed on the windward hull than the leeward hull
> > > > meaning if I place enough weight to the rear on windward hull
> > it
> > > > will fall off the wind bear away, but both hull and float are
> > > the
> > > > same length. I have to try with the board on the windward
hull
> > > minus
> > > > weight.
> > > >
> > > > Todd
> > > >
> > > > --- In harryproa@yahoogrou
> > <mailto:harryproa%
> > wrote:
> > > > >
> > > > > G'day,
> > > > >
> > > > > No, for the following reasons;
> > > > > 1 They would lift out of the water if the hull flew
> > > > > 2) Their drag would increase weather helm. weather helm is
> > not
> > > a
> > > > problem on harrys so this may not be a valid reason any more.
> > > > > 3) I don't like all the weight in the windward hull, except
> > > for
> > > > racing. Racing implies lifting the ww hull, see 1.
> > > > > 4) I have had enough trouble getting lee hull rudders to
> > work
> > > > without starting on new sets of rudder problems.
> > > > >
> > > > > Despite all the above, the rudders on my Elementarry are
> > > getting
> > > > closer to amidships and I drew a Little America's Cup proa
> > with
> > > > rudders and rig in the ww hull. Huge rm (lack of rm is a
> > problem
> > > > with these boats) but prone to windward capsize unless the
> > crew
> > > were
> > > > very good.
> > > > >
> > > > > We are about to launch a 6m proa with a pretty radical
> > > approach to
> > > > windward hull steering. Keep an eye on the web page for pics
> > and
> > > > progress. If it works (pretty big if), it will change a lot
of
> > > > preconceptions about proa steering.
> > > > >
> > > > > regards,
> > > > >
> > > > > Rob
> > > > >
> > > > >
> > > > > ----- Original Message -----
> > > > > From: Todd
> > > > > To: harryproa@yahoogrou
> > <mailto:harryproa%
> > > > > Sent: Friday, April 13, 2007 12:28 AM
> > > > > Subject: [harryproa] Rudders on lee hull
> > > > >
> > > > >
> > > > > Rob, Have you ever experimented with just the rudders on
the
> > > > windward
> > > > > hull?
> > > > >
> > > > > Or dagger board in center on leeward hull and rudders on
> > ends
> > > of
> > > > > windward hull?
> > > > >
> > > > > Or any other configuration ?
> > > > >
> > > > > Todd
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > ------------
> > > > -----------
> > > > >
> > > > >
> > > > > Internal Virus Database is out-of-date.
> > > > > Checked by AVG Free Edition.
> > > > > Version: 7.1.394 / Virus Database: 268.18.18/734 - Release
> > > Date:
> > > > 3/26/2007
> > > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > ------------
> > > -----------
> > > >
> > > >
> > > > Internal Virus Database is out-of-date.
> > > > Checked by AVG Free Edition.
> > > > Version: 7.1.394 / Virus Database: 268.18.18/734 - Release
> > Date:
> > > 3/26/2007
> > > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > ------------
> > -----------
> > >
> > >
> > > No virus found in this incoming message.
> > > Checked by AVG Free Edition.
> > > Version: 7.5.446 / Virus Database: 269.4.0/759 - Release Date:
> > 4/12/2007 7:58 PM
> > >
> >
> >
>
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