From one cheap arse (ass is a donkey) to another. I was actually referring to the f'glass leaf springs, not the rig. The Hobie rig will work fine, but it is heavy, will cause you all sorts of caught aback and out of control problems and sooner rather than later will break. Save yourself some angst by building a proper rig straight away, particularly as you will have finished everything well before next summer. ;-)
A lighter alternative to the leaf springs is a simple stay from each end of the hulls to the hounds on the mast.
Really look forward to the wing rig on a lake in a tornado pictures. Should answer the questions in a pretty definite way!
Hate to give advice when it is too late, but my engineer tells me to ensure there is a layer of off axis every 2mm through a solid laminate. Not sure if there is anything between your filament wound laminate,? which is very cool, by the way. Was the fibre prewet? Was it vac bagged?
rob
Jeeze Rob... I just a cheap ass that has a free Hobie sail sitting in the basement.Maybe, with any luck, I'll go aback the first time because the rudders don't have enough athourity and I'll totally get ass-backwards cause its a Proa, the mast will snap and sink to the bottom of the lake. I'll say bad words and go cry in my beer.
Dennis
From: Rob Denney <harryproa@gmail.com>
To: harryproa@yahoogroups.com.au
Sent: Wed, August 25, 2010 7:18:21 PM
Subject: Re: [harryproa] Re: Asymmetric Bi-directional Rudders
I just pulled them back manually. Less of a chore than rotating them, but not much. Needs another order of freedom so the set up is more complex.
Can't remeber of I told Tom directly, but it was on various lists he was on, so I presume he knows. Don't think steering was what he had in mind, and for daggerboards, they would presumably work as planned.
No reason to doubt Rick's performance numbers, but there are some practical issues that need to be resolved. Going to be fascinating finding out. What is really great is having other people experimenting at the performance end (once they get rid of their heavy ideas, that is;-)). Progress will be a lot quicker.
rob
On Thu, Aug 26, 2010 at 1:38 AM, bjarthur123 <bjarthur123@yahoo.com> wrote:
rob,
did you devise a way to flip the rake of the rudders during a shunt when testing out mr. speer's ogive sections? just wondering how mechanically that would work.
did you tell mr. speer about the detached flow? if so, what did he say?
do you think an alternate section, perhaps rick's, would alleviate the problem?
just seems like such rudders would be hugely beneficial to performance. would love to have them on my harryproa when the time comes!
ben arthur
ithaca, new york
(and looking for a ride on a proa!)
> I built Speer foils for one of the test bed harrys. Set up to rake them aft
> to get the balance correct. Tiller steered. I found that when they were
> turned one way, flow stayed attached and they were great. The other way,
> the flow seperated much earlier and they were hopeless. Could have been
> lousy shaping, but I have never had problems with NACA foils built the same
> way.