JHargrove, "Again, you have created a convincing scenario but I am speaking from real observation... in light wind and slight simple wave action on a wing. I would suggest that you make a simple modification to allow the counterbalance (rod) addition the wing.... so that you do not have to, later. It could be on a long rod and a light weight or short rod and heavier."
During construction it wouldn't be hard to extend a tube forward, or just a slot to attach a tube..... It could even be designed to be semi permanent for storage (feathering at anchorage or a dock).
I don't see much of a downside to the suggestion. I like to experiment and I certainly like options when I make mistakes : )
Yes I think I will extend the tube (s) going to the elevator to the front of the wing and I can just put in two little plugs and then make a tube to fit in the other tube.
Thanks, I'll do it.
Talador
---In harryproa@yahoogroups.com.au, <jhargrovewright2@...> wrote :
T Wood, Again, you have created a convincing scenario but I am speaking from real observation... in light wind and slight simple wave action on a wing. I would suggest that you make a simple modification to allow the counterbalance (rod) addition the wing.... so that you do not have to, later. It could be on a long rod and a light weight or short rod and heavier.
---------- Original Message ----------
From: "taladorwood@... [harryproa]" <harryproa@yahoogroups.com.au>
To: <harryproa@yahoogroups.com.au>
Subject: Re:: Re: [harryproa] Re:: Greenbird wing design
Date: 25 Jun 2015 11:37:18 -0700
---------- Original Message ----------
From: "taladorwood@... [harryproa]" <harryproa@yahoogroups.com.au>
To: <harryproa@yahoogroups.com.au>
Subject: Re:: Re: [harryproa] Re:: Greenbird wing design
Date: 25 Jun 2015 11:37:18 -0700
JHargrove, "That is a well worded and even logical argument but reality trumps theory. A boat needs close to a balanced wing in lighter winds.... or it will run you crazy... unless you have total control over the wing. Have you ever lost all wind while sailing in rough sea?"
Yes and it can be bad and the boom and sail goes bang, bang, bang even with a preventer.
The problem though isn't the freely moving boom and sail, it is the sudden stop of the freely moving boom and sail. If there was no sudden stop there would be no problem and no huge forces building to tear things up. I once saw a boat with a traveler that had been ripped out because of an unintentional jibe.
If the wing is free to rotate the elevator will naturally dampen the motion, with no forces building up. Adding ballast to the wing though will increase the moment forces and hinder the elevators ability to dampen the moment.
The secret to the whole thing is that the wing is aerodynamically balanced and a tiny effort by the elevator is all that is needed to control it.
I know it is counter to our usual way of sailing with the jib sheets so tight they hum and the traveler lines tight as a drum and the stays vibrating in the wind. The forces can get truly frightening.
I am pretty sure the forces will always be lower than a bare mast, except the total moment (from wave action) will be higher because the wing is heavier and that is another reason not to add ballast the wing.....
Talador
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Posted by: taladorwood@yahoo.com.au
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