I have now completed my latest modification to the Sk-1.
I had invisioned some type of cleat device to hold the trimmed
mainsheet while under load, so as to releive the sail servo from
constant standing torque.
My solution was to add another servo which would control the cleat,
while at the same time not counter loads to it.
Originally I had tried a “cam-cleat” device similar to a normal
sailboat, but the torque required to operate the cam was just
swapping one problem for another.
This new “cog” device works to allow a stop-knotted main sheet
to “click” into place at several notched cleated positions.
The “trip” servo pulls this device out of the mainsheet travel path
and allows the sheet free movement.
I just tried it out today while asphalt sailing in 25+ winds! I can
easily adjust my 4th channel-stick control to engage or release the
(I wish I knew how to upload pics here)
Check out photos starting at Yahoo link and continue (3 total):
Looks great Jeff. I take it that it will react quickly enough to avoid capsize by being over sheeted a bit too long?
IRCSSA US 66
Yes! The conditions I tested in were perfect for that.
In fact, when I sheet in and allow cleated action, then I ease the mainsheet entirely, then a wild gust hits, I disengage the cleat and the entire mainsheet length is fled instantly, possibly faster than the standard arrangement control stick.
I was afraid that the stop knot would be stuck while sheet was under loads, but it “pops” out quite easily.
I have a “knuckle”, (not seen) inside the cog arm sheet path, where it pushes out the line as the arm rotates opposite direction.
This is critical when the mainsheet has been eased off, because you need opposite forces against the cleated forces to pull the knot off the cog tooth.
You can make out the mainsheet deflection over the “knuckle” in the “uncleated” photo.
I also used your suggestion into the cog-servo, where the “cleated” position has acting forces directly against the servo axis post, thus not placing servo under as much loads. No servo hum, even when I pull as hard as I dare on the cleated mainsheet!
Now thats what I call “standing torque”
Hmmm, that’s a consequence I hadn’t thought about. It seems like this could cause the boat to drop out of a hike so fast it will slam onto the ice (or ground). As we both know from full sized iceboating, this will cause a very noticible loss of speed. But of course, that is preferable to a capsize & total loss of speed…;-).
BTW, did you see the jam cleat arrangement recently posted by Earl Boebert in the Footy section? http://www.rcsailing.net/forum1/showthread.php?p=42629#post42629
Well, like I said, thats only one option for control.
As another practical example; After having the mainsheet fully trimmed and cleat-cog locked, I can sail with the sheet control eased back to 80% position (unloaded), with the cog-cleat at 100%. When I trip the cleat, I would only get 20% eased out instantly, up to the sheet control setting. Then I operate the main sheet normally.
I have both the sail sheet and cleat-cog on one joystick, so its quite easy to make adjustments of all ranges possible.
BTW, you do know that I am running those bendy mast designs for strong winds, so the “hike-drop” situation is no where near instability to the degree you are thinking.