well did some measuring and figuring. if I use a arm winch and IF i can get 180* rotation I can get 4.5inches from full out to full in. and if I go double purchase then I’ll get 9 inches of sheet travel…
so…with a beam of 3.5 inches with a drum that goes 360* then I get 11 inches of travel… so I wonder can I modify a servo to go 360 or more and then use the dx6i to program end points…
I did a double purchase on my first RG to get enough throw. Worked fine since I put a bungie on the block, so the block was pulled out when sheeted out. Really helped deal with the light air.
Hi Marc
I use a HS-815 arm winch with a 3 inch arm,180 degrees and a double purchace and I get 11 inches of travel. 3+3x2=12. Minus an inch for some unknown reason
Don
Hi Marc
I modified a few servos for 360+ revolutions. It involves changing out the pot for a multi turn pot. I found the resolution to be very poor. As a servo approaches its stop point it slows down(to prvent over run and hunting). With a multiturn pot the ohms are spead out more(sort of) so the servo slows down sooner, and under load, runs out of power shy of the stop point. So depending on the load it stops in a different spot. Mine usually buzzed so I’m assumeing it was eating batteries. From another point of view you have to modify two or more servos so you have a spare. From yet another point of view it makes it harder to sell the boat because if the servo breaks the new owner is hooped.
Just my experiences
Don
well no joy last night…my Fut 3102 which pull rudder duty on my vic,and soling and also rudder and sail duty on my footy I can only get 90* of travel with the dx6i programming… which means based on the hull space inside and servo arm length with a a double purchase I’m only getting 7" of sheet travel… which means my jib sheet attachment point is about 15cm from the deck attachment point to give me my range of motion I need. My jib club is calculated at 47cm long…
the 3102 has 64oz of torque @ 6v. and since I’m cramming 7.4v (lipo) down it throat i may be in the 7-80 oz range of of torque I guess at this point. continue building…and see what happens…
I’ve only sold 2 complete boats a vic and an Odom… I would not plan on selling the rgit would get ransacked for parts and thrown away…
Well imitation is the sincerest form of flattery…
finished the rig tonight…this morning. waiting for the gws winch…
Hi Marc
a simple remark, for a well balanced jib , the pivot point should fall at about 25% of the jib base as reported in the attachede picture.
Obviously the Jib CE shall be positioned according to the centering criteria. The mast rack shall be adjusted accordingly.
Cheers
Claudio
Claudio…
I have had good success on odom, footy, ec12 and buy putting the jib attachment point at the forestay, like a real sail boat. the downfall is thatyou have no leach tension. Which is the reason for the jib club to be so long from the forward most end of the clup to the head of the jib is a “topping lift” only rather than lifting the back of the jib club to add the needed shape it pulls the front of the club up with pulls the aft end down to add/remove tension in the leach.
It has really worked well for me. in the lighter air we generally get the performance of the boat has been good. now whether or not it just the better thumbs or the placebo effect. who knows. I feel that I can point much better than boats conventionally rigged…and I can ajdust the leach without altering the forestay tension. I have found that this setup doesnot like the large sails of the ec12 or high winds. I did make a radial jib club fitting for my victoria and I was really pleased with the performance, but the added weight up front was a bit of a dentriment when going down wind in heavier air…
Hi Marc
two remarks
The Delta Rig with a single sail when running is putting sidewise the CE and therefore rendering the route control more tedious.
This fenomenon does not exist with the use of main and a radial jib, because the jib CE it is compensated with the Main CE, if butterfly run is used.
The delta rig if pivoted at 25% permit to avoid, partially, the side effect of the CE when running.
Now, this is what generally it is done on various models, if you are happy with your choice, my comments are superfluous.
Cheers
Claudio
claudio I agree that when on a run…with the single sail would be like piloting a motorboat that has two engines with only one engine running…the boat will be pushed to the side opposite of the sail. I did notice this on my footy…
on my RG there is about 1/2" fore and 1/2" aft for mast adjustment. and about 1.5" for the jib/deck attachment point. Also on the jib club. I can adjust the pivot location…Which I’m sure will happen during the on the water phases…
Interesting to see a very old idea resurface with a new name… The first post claimed the idea dates from 1992… Sorry, but I did one in the early 1980s… I called it a “Jib Una-Rig”… Unfortunately, no photos from that long ago… All I can tell you is that it had moments of brilliance and did, indeed resist diving on the offwind legs to some degree… Obviously, overall, it wasn’t the answer or today all boats would have them…
A couple of pages back there was a drawing of a similar rig but with a quadrilateral (4-sided) sail with a boom top and bottom… I tried that as well, and it was prone to huge creases running diagonally as I couldn’t get the “balancing act” to work over a range of conditions… Adjust it for one windspeed, and as the sail twists and pulls the aft ends of the booms closer together you get diagonal creases…
I also did a gaff-rigged foresail on a schooner… I did manage to tame that by having an “upside down” vang to keep the yard at the top from drooping with twist… which also caused diagonal wrinkles… The boat also had a sheet running up the mast to control the amount of twist… both sheets (top and bottom) moved together… The yacht was a Schooner version of my “Swiftsure” and was actually able to plane on a reach… and it was based on an EC12 hull… There was a LOT of power available… Not much surprise they used Schooners for fishing where they needed huge amounts of power to drag the Trawls on a reach…
Bob
I went back to one of my books to check the Jib set up used in the 1st developped Staysail Rig , according to Bolger, in 1922, almost 90years ago !
See pictures from the book. Only in 1985, 63 years later, the design was taken back again with the Corsair 24. The jib used a pivot point at the forestay, but a man was holding the rudder !
Reading the Bolger’s book gave me the idea to build one in 2004/2005 see pics called CDCAT. Was a very fast boat but required particular attention to mantains the right ‘attack angle’ to avoid getting into stall.
It is not escluded that the same arragement could be tested again with my newest design FDS-111 (see pics)
Cheers
ClaudioD
interesting hull shape Claudio… one question.
in pick #2 angled jib club…why so severe of a bend…
Marc,
it happen 3 minutes before final breakage just in time to take a couple of pics !!!, at the beginning was almost strait. (see pictures) Was my faulty construction with two carbon tubes retained with an alluminium tube that started to bend until failure !
Another learn lesson !
Cheers
Claudio
but why have it angled at all…you have more than enough space to use a single straight boom
being a relative large jib base, when the boats is heeling, there is the risk that the boom may touch the water therefore is good to have a curved boom. At that time I was taking just two tubes and linked togheter with an angle instead of laminating a curved bom.
ClaudioD
I guess it could hit the water…if you are reach, or the boat gets rocking when going down wind…
at any time including going around the buoy, etc
ClaudioD
not supposed to touch the marks… : )
Since the jib is a relatively low aspect ratio, the jibstay (and the pivot line) are on a large angle to the vertical… The result is that as the jib is sheeted out, the clew lifts pregressively higher… and therefore gets further from the water… Although the boom is relatively long, having it dig in is much less problem than on a yacht with a long mainboom such as an EC12M…
That angled pivot also means that when you are on a run, the plane of the sail is tending to lift the bow… The boat is therefore less prone to diving on the offwind legs as well…
Bob