i took some pics using a fan, but the end plate was a folded peice of cardstock… so not really a viable test…I will make a new sail out of mylar and get some really close tolerances. i think you really need a good seal…between the wing and endplate
my gaff is still not glued in place hence the crooked appearance from the top down view.
You are rihht. Probaly the worst possible solution is and emdplate with a small gap. Not only is the effect of the endplate negated, narrow high-low pressure gaps generate very substantial drag in their own right.:graduate:
Spot on Angus, which is why a deck cannot be an end plate unless the sail rigidly sweeps the deck in contact with it. In model aircraft terms a gap if even 1/32" between a rudder and it’s fin will spill air and be less efficient than a sealed gap rudder, elevator or aileron. The gap must be closed to benefit from the effect.
I think that a sail top end plate would be a good idea if the yacht always sailed upright but I worry about what happens when the boat heels and the end plate becomes a ‘heel exagerator’ / wind catcher.
only one way to find out… 
that why I want to go mylar for the sail as i think it will hold a better edge/seal against the endplate…
I’m now envisioning Graham selling his footy kits for $23,891 because of all the technical advancements…
OTOH…
“Anything not expressly prohobited is allowed…” 
:scared: :devil3:
Marc, I think you have very cleverly solved the problem of the CoE moving dependant on which tack you are on.
I tried to see how you had butted the carbon tube? Was it with a rod?
Rgds
AndyT
Andy,
its all pultruded carbon tubes. with only CA holding it in place. since I like the rig, this weekend (when I work on the 507)I will make up a small batch of west and then using spider wire coat and wrap the joints. for a permanaent joint. again with the small surface area, its not a huge amount of force. I’ll take some close-up pics of the joints tonight. before I wrap them (boy scout style) and then trim the excess so it purty…
I’ll need to head backto the hobbys tore for some more tubes for the larger rig…
that also sell square tubed, and I’m thinking that the square tubed might be better suited for the offfset mast
Very true marc, go for it. If you make a hand help streamer on a thin wire you should be able to sample the air just aft of the top trailing edge with and without the endplate to see if the vortice has been reduced. That is the main sign that drag is being reduced by the endplate.
Graham
I made a special fan for testing my 1M sails a few years ago. I used 4 8-inch muffin fans ( big computer fans) bolted together in a diamond pattern with a solid state speed controller, light a lamp dimmer. It creates a uniform and big wind flow that can be easily aimed or the speed changed. It worked better than a box fan, unless you stack 4 of those together, and set to low speed.
Before that I set the boat up between the houses where there was a constant light breeze.
for the footy I used a 12" oscilating fan on a chair… with the ocilator disabled…
not perfect, but i guess it works. its my first “wind tunnel”
As a simple, discrete source of smoke without TOO much aeroynamic disturbance, use joss-sticks.
:graduate::graduate:
Or sea-salt scented insense sticks 
for smoke
IMO, 1 fan is too focussed to use to tune or test sails, so I built a large (wind source) with slower speeds.
Marc this is good news but do not understand the phrase “make up a small batch of west” whilst i can imagine it i have also not heard of spider wire.
With the tubes being carbon would it be easier to bind with carbon fibers and then coat the joint?
I do look forward to the close ups
Best wishes
AndyT
Andy
WEST = poxy!
:graduate::graduate:
Angus ~ Where did that Acronym come from or should I not ask?
Rgds
AndyT
Wood Epoxide Satuaration Technique.
:graduate::graduate::graduate::graduate:
Spiderwire
(http://www.spiderwire.com/) is a brand of high strength fishing line that comes in monofilament and braided styles.
I think he means West systems epoxy, about the most expensive epoxy you can get. There are others that are more affordable, like Lord Chemical epoxy & acrylics.
West System 2 part epoxy. Yes it is expensive…but it works very well, and I can find it locally.
I use 30# braided spiderwire. probably overkill for what I’m doing…but its what I have laying around. Never thought about using carbon threads, I guess I should start ordering thread and some carbon fabric…and do it right…and learning about it so I can catch up to nigel…
I don’t have a big fan so I go with what I got…
Thanks Marc and others ~ look forward to the photos
Rgds
AndyT