New Jib Design Idea

In the original Fractional rig (1930-) by giving more tension to the back stay, the mast sags, flattening the mainsail and at the same time tightening the jib stay

In this type of Fractional rig more sheet tension means more camber and less twist at the top of the mainsail

and less tension means a sail with more twist and at the same time flatter

On the other hand, the tension on the jib luff is from below

 

Three different rigs

(1) Fractional rig with back stay

(2) Fractional rig without back stay and flexible mast

(3) Fractional rig without back stay and with a very firm mast


(simply perfect for creating misunderstanding)

 

(MiniTransat)

In the IORs of the 1970s the headsail became larger and larger until it was 66%, a gigantic Genoa

and in the MiniTransats of the 1990s the mainsail became larger and larger

that is to say:

the rules are

A) the course of the race
B) the rule of the race
C) the inexorable law: cruising sailboats imitate racing ones

(in fact right now we see outside the high competitions the trend of making mainsails with a peak at 90 degrees, a new superstition)

 

The problem

The problem is that you give a professional athlete a machine that does a tenth of a knot more upwind (or one knot more downwind) and no one can beat him.

Hence the sense of sacrificing all the design to what seen from the outside is a complete trifle compared to Functionality, Versatility, Safety and Comfort

it is an explosive cocktail, a constant tendency towards delirium in "let's see who pisses the furthest"

 

More sheet tension only means more camber and less twist if you don't know how to use the vang and traveller properly. The fact that you seem to be unaware of this explains why you seem to keen on the combined traveller/vang, which is an ancient idea discarded long ago by all those who have tried it in monos.

 

Upwind sail aerodynamics: a RANS numerical investigation validated with wind tunnel pressure measurements

IM Viola, Patrick Bot, M. Riotte

 

On the one hand we have Upwind and on the other hand a different world: Downwind

and within Upwind we have very different zones

A) < 6 knots
B) between 7 and the designer's wind
C) > designer's wind
D) between 20 and 30 knots
E) > 33 knots

 

Chatting about these issues with words can be entertaining

buuut it is a question of

1) numbers
2) calculation of forces and
3) priorities in the design

 

the quest for a very high coefficient, box A11, pales in comparison to the delight of Versatility of a huge range of coefficients, box A13

and on top of that the Twist function, box A14 in this my model I use the formula for the twist function developed by Fabio Fossati in the wind tunnel of the Polytechnic of Milan

the 3/4 fractional rig is a marvel because on the one hand it has tremendous upwind Versatility and, on the other hand, it is a very good balance between two worlds: Upwind and Downwind

 

The NS 14 does not use a spinnaker

I love its philosophy

The funny thing about this is that the weak point of the Fractional rig, which is not very important (Upwind with very little wind) is solved by building 1 wing with 3 pieces and a large bowsprit, like a Itchen Ferry

Jib
StaySail
MainSail

Two comfortable sails on the bow and a big Mainsail

 

Wonder, 1860, Itchen Ferry

 

Is that mast supported with many sets of diamond stays? I see no spreaders.

 

If the 3/4 rig has proven to be more effective, why is the masthead rig so popular? Less likely to break the top portion of the mast?

 

Aaah ...

that's right, there are no spreaders, and now I can't remember what sailboat it was, let's see if I can find it:

Document sans titre https://www.histoiredeshalfs.com/Histoire%20des%20Minis/N%20N%20N%20N.htm

 

for a lot of reasons

1) 1950's Fractional rig was inferior: the mainsail had a ridiculous shape and a ridiculous size on top above the jib

2) masthead rig (1947-, 1970-) is a rig very well suited and very powerful Upwind with 10-15 knots of wind ... typical of summer regattas like the One Ton Cup in Marseille in the 70's

3) because the 3/4 Fractional rig of 1980's were complicated rigs with very thin masts that logically scared cruisers

4) because 3/4 without back stay is difficult to implement beyond 1 Ton Displacement with an aluminum mast and carbon fiber masts are expensive