Subject: SV: Re: SV: [harryproa] some more Elementarry data points
From: "jjtctaylor" <>
Date: 3/10/2006, 12:23 PM


The novelty is making it work efficiently and safely beyond a single
prototype design.  Wings for the masses.  That means durability,
weight aloft, mass counterbalance, rudder response and an assortment
of "other" details has kept wings out of the mainstream for decades.

Endplate on top is an option.  If the proximity of two wings is less
than a chord width then there is an induced drag loss from mutual
wing interference.  Only get a true mutual gain on a double wing when
the upper wing is projected forward by 20% or so overlap.  That
should not surprise the forum as is the typical jib/main
arrangement.  See

End plate is necessary only as a winglet to eliminate the tip
vortice.  But plates can be individual per each wing.  Wing twist is
all about managing the tip vortice, shedding the vortex while keeping
positive lift with the airstream changed.  No tip then rigid wings
have been modified with splits to emulate twist. (Complicated and not
elegant).  But with wing assembly on the ground and not too heavy
then it is practical to try linking them together at the top.  Just
some more weight aloft.

Common axis is nice but have to deal with the wing subframe at
assembly.  Employing my best KISS principle, easier to assemble as
two completely separate wings and wing mass counterweights
standardized for each identical wing makes fabrication easier.

Of course, rudder is attached directly to one or both wings and
teleflex cable runs to helm position on the ww hull as you suggested.

There are engineered choices to be made, but challenge remains cost,
weight, and robustness.  So far none have reached a satisfatcory
balance to go to market.  Therefore the wing design has to be clever
or better than past experiments.


--- In, Kenneth Hernemalm
<hernemalm@y...> wrote:
> JT,
> 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
> here).
> 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
> nice.
> 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!

> /Kenneth
> --- jjtctaylor <jtaylor412@c...> 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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