Well this guy did learn some lessons of which one is, not to blunder with calculations. (That is how you make Titanics sink). Paul was of course right, the friction in the outhaul system is to big for the minuscule tension of the sheet. Remains only to make it manual, so the idea is not dead. I will come back to that at a later time. Anyhow this discussion resulted in a somewhat better sail plan. Maybe there are some misses there which I have not discovered yet. Stay tuned

Eyeballing now.

Would the tension the sheet has to handle in the case of the AJ not be the wind force on the he area of the main minus the he area of the jib?

My sole purpose was merely to urge caution.

A vessel this size will create a lot of interest.

I wish you well.

OK, that's a planform (profile outline) I am unfamiliar with. Not having CAD or an inclination to use geometry, I'll take your word for it that the jib comprises 34% and the main comprises 66% of the canvas area (which may not be the actual sail area, if there is a slot)..

What is the balance of this proposed rig?

Since the dimensions of the slot are not shown on the diagram its hard to be sure, but it looks as though the mast centreline here intersects the boom at about 32%. That would be a conservative amount of balance.

However, with this unusual sail geometry it is evident that that rule of thumb for estimating balance is not conservative (as it would have been with a normal planform) and probably does not apply in this case. 

If you want to calculate the "balance" of this rig, and be able to compare "apples with apples" you will need to do the calculation, and include the area of the slot as part of the sail area geometry. It probably won't affect the result much, but CAD will spit it out for you easy enough, why not do the calculation? 

It still looks problematic to me, or should I say "marginal" and I would repeat: take care you don't over-balance. I would suggest consult Paul McK if you have not already done so.

I would be curious to know what the properly calculated balance is, and even more curious to see what happens when you try this sail out in practice.

Good luck!

Nic: I cannot visualise a split rig with the mast at the 33% point, and jib panels which comprise 34% of the area, so without seeing a diagram, I don't understand, and won't comment any more on that.

My comment is based on experience with a close relative of the aerojunk: the SJR, which is a split rig with 33% balance (that is, the mast CL intersecting the boom at the 33% point).  The combined area of the slot and the jib panels is designed to be ahead of the mast centreline on that rig. The pull on the sheet is quite low. I would not like it to be much less.

It's an aerodynamic balance and I have no idea how to calculate what the pull would be, but generally the higher the balance, the lower is the pull on the sheet. Until you get somewhere near 35% (perhaps a smidgeon more) when the pull will be zero. At that point, you would be unable to let fly the sheet in a gust of wind, and probably also unable to steer up into the wind. You would be sailing in a runaway junk, a situation I would not like to contemplate.

There will be a similar limitation on the amount of balance you could safely give an aerojunk, for the same reasons, and you need also to allow for unforeseen factors such as spars bending (mast or battens) which could further add to the aerodynamic balance in a given situation.  That is why it is wise to be careful with balance, and how you calculate it, when you start to venture beyond 30%. Without knowing (or understanding) the geometry of your rig, I can't say more than "just be careful".

[I have corrected a mistake in my previous post, by the way. "Balance" ("mast balance) is the total area of the sail profile outline ahead of the mast centreline, divided by the total sail profile area. 33% balance allows for a small margin of error. From experience with model racing yachts with "swing-wing" rigs, Slieve (the designer of the SJR) has reported controllable rigs with up to 35% balance.)

The "sail profile outline area" includes any slot, treating it as part of the sail area. It is a mistake to consider only the area of the jibs and the area of the mains when doing the calculation - as you seemed to be suggesting. That can lead to a bad error. That was my main point, really.