Wing Tip Rig:"bent back tip" /square top rigs

The Wing Tip Rig™ was developed over the last few years in two main versions: One, was a basic square top rectangular planform sail using a carbon gaff to hold the top of the sail; Two, is a “peaked up-bent back tip” version of a square top where the leach is longer than the luff and where the tip is angled back around 40-45 degrees.Both versions have a very unique feature: an adjustable upper outhaul. Both rigs were developed to allow the use on models of sail plans with superior planforms to the old triangular pointy rigs so common even today. The problem in their development was that most full size rigs that use this type of sail( many multihulls,IACC boats, JS9000 and her bigger sister the JS40 and the mini 6.5 monohull oceanracer’s to name a few) use full battens which have been very difficult to use effectively on models since they sometimes required the batten camber to be “popped” over to the right side and of course on models that is difficult to say the least. Some new rigs under development make use of full battens and DO NOT have the pop over problem.
The Wing Tip Rig was found superior upwind against an identical boat equipped with a triangular main in testing that included many (over 50 ) races. There was not much to notice downwind between the two but upwind the Wing Tip Rig was superior in both speed and pointing.
A newer version of the rig is now being tested that includes a square top jib; it is being tested on a 16’ hydrofoil and on a one meter model.
This type of rig in all of its versions offers some practical benefits as well. The rectangular sail plan has a lower CE than an equivalent pointy rig-which also nullifies the weight concern of the ultra light weight gaff: the pointy rig mast is taller!
The Wing Tip Rigs used on models have another design advantage: they are reefable allowing a boat to just have one rig instead of three or more --saving big bucks.
These rigs seem to offer great advantages upwind with no disadvantages downwind and have extremely good gust response–far better than a triangular sail. With the camber at the top and bottom easily adjustable and twist control thru vang tension this sail is much more configurable for different conditions than a triangular sail. When combined with the aerodynamic benefits of the rectangular or semi-rectangular planform and tip shape this makes for a very fast upwind sail. Aside from the tests run by microSAIL! the US 10 Rater Class has been experimenting with square tops finding them superior to pointy rigs as well.And the newest canting keel model yacht the Ultimate Warrior from Wind Warrior Yachts in NZ has a square top main…
These rigs and their newer variations are rapidly becoming the norm for high performance full size rigs and will ,thru the Wing Tip Rig™ and other rc variations, make similar inroads in model racing.
UPDATE_VERY IMPORTANT: Matthew Lingely just pointed out that I did not specifically mention that the tip on the bent back tip rig as used on the Spinnaker 50, micro Moth, and F3 ROTATES. This is critical in combination with the upper outhaul to achieve a perfect twist to the rig for every condition as well asto provide excellent gust response.

UPDATE: November 03 issue of Seahorse magazine,p.37, on square top rigs:"…the Square-top helps the sail to achieve an even twist profile, improving the spanwise distribution of lift and reducing drag."
Doug Lord

High Technology Sailing/Racing

Matthew, the answer is here. Something new is that all our sails are now being designed by Sandy Goodall.
The peaked up bent back tip is the fastest of the two versions without a doubt and both are faster than a triangular rig of the same sail area.
The bent back tip ,for now, utilizes an extruded solid carbon rod which is fine for the one designs it is used on. An improvement would be to make a “bent back tip” with a hollow carbon tube. Ball bearings don’t appear to be necessary but in an open class example of this rig I would probably use them-testing would show the answer which I have not explored.
Note: I will help anybody anywhere experiment with these rigs for free -because I believe that the square top with a gaff or the bent back tip both with upper outhaul offer tremendous potential upwind in classes where they would be legal.So don’t hesitate to write with any questions…

Doug Lord
–High Technology Sailing/Racing

is there some where i can get iformatioon on how to purchase the mains. simmaular in apperance to the IACC class boat. i am building one in the 1/20 scale. and would like to have a full main

Cougar, at this point the Wing Tip Rig™ is made only by microSAIL! and only for the specific boats produced by that company. There are two major types: the one used on America One and the one used on the Spinnaker 50/F3. These rigs enable effective modern planforms to be used without full battens. Any sailmaker should be able to build the sail and I can tell you how to make the head work properly.So post your questions here or e-mail me and I’ll help you anyway I can.

Doug Lord
–High Technology Sailing/Racing

Courgar: Doug’s wing tip rigs look nothing like the top of the mast of an AC boat. Doug has a curved solid carbon fiber rod (a sort of a gaff) at the top of his rigs. IACC boats all strive to reduce weight at the top of the rig. You might talk to some of the many sailmakers who regularly supply r/c sails (Carr, Sterne, Bantock, Black Magic, etc.) to design you a set of model IACC sails. I am certain they can fulfill your needs.

Cougar, the full size IACC boats all now use versions of a squaretop rig because of the aerodynamic advantages. Our America One rig used on the 65" IACC model uses a gaff at the very top of the square top main specifically to eliminate the need for full battens which -so far- do not work well on models. Above the gaff is a samll endplate made of sail material. The gaff has an adjustable outhaul just like the main boom -and together coupled with the vang they probvide wide adjustability and perfect twist and excellent gust response.
This gives the sail the aerodynamic advantages of a square top planform without the inherent disadvantage of full battens.
Roy is dead wrong about the gaff: it is made of hollow carbon tube on America One and the total weight including the large carbon mast crane is LESS than the additional weight of a taller mast that would be required for the same sail area and boom length.
I designed this rig and the “bent back tip” version used on the Spinnaker 50 but our sails are all designed by Sandy Goodall one of the worlds foremost sail designers.Any sailmaker you went to if they didn’t understand how to make this kind of sail could consult with Sandy at very reasonable rates-that is his business.

Doug Lord
–High Technology Sailing/Racing

Pictures don’t lie. If one looks at Doug Lord’s website anyone can see what his rigs look like and compare them to a contemporary IACC boat. If you are trying to duplicate an IACC rig, judge for yourself if Doug’s rigs are the right model.

As to my statement about the “gaff” on Doug’s boats being a solid carbon fiber rod, that comes from his many posts on making such rods and his own statements that they are used on some of his rigs.

On the concept of the “wing tip rig” generally, Doug stands alone from all other r/c boat and sail manufactuers and designers as no one else in the entire world makes rigs similar to his.

Cougar, contact Mark Gee ,class secretary of the 10 Rater Class in the USA; you can find his address under the 10 Rater Class on
He has been testing his own version of a square top rig (that I have not seen) with good results.
MOST classes OUTLAW the Wing Tip Rig? in its bentback (superior) and gaff squaretop versions because the rules were written in the Last Century when triangular planforms were thought to be state of the art. It is unfortunate that many of the existing development classes are saddled with such restrictions with the possible exception of the 36/600 and 10 Rater. Most newer startup development classes allow this rig and variations of it.
It is important to note that the square top rig on America One was designed for that boat over 8 years before a semi -squaretop ever appeared on an IACC boat!! The upper endplate piece I mentioned earlier can be changed slightly to EXACTLY mimic the “look” of a modern IACC boat and that change appears on the most recent America Ones about to be delivered to Europe.
Though there is room for much experimentation with full battens this rig gives an aerodynamically superior planform without the need for all the weight of full battens and does so with a wide range of adjustment including the upper outhaul.
Look at the boats using this type of planform in full size sailing-more and more all the time because the planform(sideways viewd shape) reduces drag compared to triangular shapes; when is the last time you saw an aiplane wing with a triangular shape and pointed end?
Contrary to some myths these aerodynamic characteristics translate directly down to our small boats–again look at the shape of model airplane wings as well.(outboard end)
UPDATE: the “gaff” on America One is made of hollow carbon tube; the “bent back” tips on the Spinnaker 50 and F3 are made with solid carbon rod and even so are equal to or lighter than a conventional rig with the same sail area and boom length.For development classes there are methods available to make “bent” carbon tube and reduce weight even further…
Doug Lord
–High Technology Sailing/Racing