Subject: Re: Re: SV: [harryproa] some more Elementarry data points
From: "Rob Denney" <>
Date: 3/10/2006, 7:16 AM

I will leave JT ot explain about the biplane rig.
The tornado guys I am sailing against on Sunday are the challengers for the next Little America's Cup, to be held here next year.  I am trying to persuade them that for a heavy air venue such as Perth, they need an Atlantic proa.  They are fixated on foils.   However, they have the 3 piece wing rig from the last challenge so we will see what can be done.  I offered to pay for a set of hulls and beam (only one needed for an AP) for a 5.5m version to test it out, but there were no takers.
The foil proa is still happening, just waiting for the owner to pay some money, although I am not sure exactly what it will look like yet.
Elementarry's speed hump at 16.8 knots may or may not exist.  Should have a better idea in 20 knots (new forecast) on Sunday.  I tried a planing hull on U.  The boat would not climb over the bow wave, just sailed on the front part of the rocker.  Probably needs some more work, although pointed sterns are not conducive to planing.
----- Original Message -----
From: Kenneth Hernemalm
Sent: Friday, March 10, 2006 7:37 PM
Subject: SV: Re: SV: [harryproa] some more Elementarry data points

I like the concept. Why not connect the wings with an
endplate at the top? I imagine that together with very
little or no gap between bottom end of wing and deck
should give a very nice effective A/R. Using constant
profile foils for easy production and having the
biplane wings rotate around a common axis would rid u
of quite a bit of mechanics. I like your idea about
using a teleflex cable, but why not attach the wing
rudder directly to the wings with a rod and then
control AOA for the wing from the helm positition with
the teleflex cable?

I don't think this concept is all novel, recall seeing
something similar somewhere on the web. What I have
not seen is someone putting something like that on a
100 kg, 7.5 m, l/b=20 Proa! This is the first time  a
rigid wing could really show it's benefits outside the
category "very_expensive_and_fragile_speed_machines".

About the real fun - I think Elementarry must be able
to leave displacement mode in order to improve
Elementarrys upper speed range much above 16 knots.
Considering it's round bilge, double ended lee hull
will it plane? Would not CLR moving, transitioning
from displacement cause problems?

I think that to plane - Elemetarry needs either a flat
bottom - 'Dory style' to possibly take it into
plane(Crew weight on flying or planing ama should help

Or take  the hull out of the water - Foils! A set of
nice foils, dimensioned to take the hulls out of the
water @13-14 knots or so, should make the resistance
curve look horisontal from liftoff into silly speeds,
compared to without foils. From what I read, Mark is
working on a hydrofoil solution? An update would be

Elementarry has obviously proven itself to be a rocket
despite an undersize rig. I am so impressed by both
the potential for this concept, as well as by what is
already achived!


--- jjtctaylor <> skrev:

> Kenneth,
> I have suggested to Rob a rigid Biplane wing set
> which is functionally easier to use, and a
> symmetical foil is really not a complicated effort.
> Just takes time to fab.  Chain or pulley
> set inside the LW hull gangs the wings together so
> only a single air rudder is needed. 
> Simple teleflex cable to the rudder controls wing
> angle of attack.   Rob has an aeronautical
> engineer friend who has a foil shape that would
> work.  Only technical effort is what Rob
> does best, optimize the wing spar for weight and
> strength. 
> Wings size is 4 x 20 ft each for proper aspect ratio
> and satisfactory performance.   The
> real fun comes if he can overcome the downwind
> velocity loss (bubble) by accelerating at a
> beam reach then bearing off downwind as he moves
> faster than downwind air, moving the
> air forward as he bears off.  Wings can do that if
> the hull efficiency is right.  Then you have
> true screamer, upwind and down !
> JT
> --- In, Kenneth
> Hernemalm <hernemalm@y...> wrote:
> >
> > Congrats Rob, that is quite a feat!
> > Maybe not that surprising about the Una rig
> working so
> > well - Elementarry being a low drag boat is
> obviously
> > well matched with a low drag rig. Good move! Will
> be
> > very interesting to see how it works out with more
> > canvas. Optimizing for low drag with a wing mast
> > should pay off. Can't help thinking a rigid wing
> would
> > be cool on Elementarry, but i guess that would not
> > make Elementarry very elementarry ;)
> >
> > Still planning for a Europe tour this summer?
> >
> > Good luck to leaving Tornados in the wake!
> >
> > /Kenneth
> >

Bästa hälsningar

Kenneth Hernemalm

om du vill ringa finns jag på 0701-593302 eller 031-552121

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