just puled the first hull from the new mold,its not perfect but ive been in a bit of a rush but its sertanly going to do the job nicely.onece again probly still a bit overkill with the layup of 2 layes of aprox 100g glass but nice and string atleast.will be doing the second tomorow and then hopfully geting them in the water very soon
just a quick pic of the secon hul i puled thismorning and the fins and masts now done
UK;
Making small sails is a demanding job. A good deal of precision is needed in joining the panels and laying out the curves.
I have seen several references of Footy sailors having used trash bags or other plastic bags for fabric. I propose that that is a very poor material for sails. True we want to keep the weight down. On the other hand we’d like the sail to hold its’ shape once done. There are numerous fabrics that will do better. One of them is screen printing mesh. A mesh count of 390 is made with very tiny yarns that are about 28 microns in diameter. Even so, the stuff is wicked strong. It is also calendared so that the mesh holds its shape pretty well. Other fabrics are the lightest Tri-Spi, or very light spinnaker cloth as in 3/4 ounce.
So much for fabrics. cutting a small sail involves placing some curves in appropriate places. First the Main luff… The curve you will use is much dependant on the bernd of the mast. If you are using a rigid luff spar like CF tube, then bend will be slight. In that case I’d start with a luff curve of about 2 to 2.5 millimeters. The curve should have its maximum deviation from a straight line at about 35 to 40% up from the tack. The foot will likely have a curve of about 2mm with maximum at about 40% back from the tack. Cut he leech straight until you have mastered the other technicalities. A roach in the sail does very little anyway so dont complicate things.
Now if you are using panels,( you need at least two) then the seams need to be done with great precision. These seams are also curved. The panel joining edges themselves can be curved or if you prefer to cut them straight you simply make a wide seam at the luff and leech and a narrow one in the center of the seam. Sailmakers call that process broad seaming. The seam curve is a critical matter and the smaller the sail the more difficult to make with precision. There are systems that use curved blocks to affect the broadseam dimensions sort of automaticly. The blocks work very well. The problem is that making the blocks is a complex job and you neeed a lot of them because the broadseaming will be different in different parts of the sail. Forget the blocks for now. Just put a curve of about one to one and a half millimeters in the longest seam. Maximum deviation from straight line at the center of the seam at about 50%.
As we are working in very small dimensions this curve business can get very tedious. It helps a lot to get some stuff at the sewing and notions store called “basteing tape”. It is just double stick tape that is very narrow and thin. One can sew through it without difficulty. Footy sails probably do not need to be sewn at all. Just tape the seams. The tape will allow you to make sails that can be changed if you do not like the looks of the finished job. Peel the seams apart and change as you think best.
If you are using a jib, it will also have a luff curve. BUT the curvee in the jib is a negative one. The curve goes inward toward the centrer of the sail. The dimension of the curve is a function of the sag in the luff. A loose luff wire (in this case a string) will need more curve than a sail cut for a tight jib stay wire.
The process of making a good sail is every bit as intrigueing as making a good boat. In the case of the sail, a great deal of care and patience is required. One could say that a hull requires the same, but the sail thing requires a lot more precision. The thing to do is experiment. once you work out the appropriate curves you are on your way.
one down one to go
just finished this one of for my brother as you can see it has a few of the first boats parts
seams like its not of mutch interest but i mayaswel finish the thread now so hers the second boat done hopfuly testing tomorow may try and get a vid if i can
i cant seam to get the file size of the yellow one down to fit on here so just click on the link bellow
http://static.rcgroups.com/forums/attachments/1/4/7/5/5/a1624123-172-DSCN5058.jpg
The new boats look great Charlie!
My version of your boat sailed well,her performance has influenced further development in lighter and narrower boats.
please post some vids of the new boats sailing if you can.
cool glad you got one in the water will try and get some vid tomorow.from the pool test they look to be a fare bit lighter than the origanal(still dont have any scales) looking forward to geting it redgistared in the uk and try it against some outher designs.
ps does it cost anything to get them redgistard and race? many thanks
not a penny!! give Angus a pm and he will sort you out!!
ok cool oh and one last thing i couldnt figer out from the rules but is tere anything saing that the ruder slot in the box has to be in the center?
Yes…the mearsurment box itself is tightly controlled.
yea but the its not actualy stated in the rules on the pic of the box?
“B.1 With the exceptions listed below in B.2, B.3 and B.4, the boat in racing trim shall be capable of fitting into an open-topped rectangular measurement box of internal dimensions 305mm long, 305mm deep, 153mm wide, with 6.3mm wide slots for projecting spars and rudder, as shown in the diagram.”
Diagram clearly shows the slot in the centre…centre line is marked in the diagram.
Seems pretty clear to me.
ok just wanst to shore as it wasnt in the writen rules ie a,b,c may have to change the rudder to under the hull ir just get a little more travel on on it.thanks for clearing it up
quick tec queston whats the reason for the boat when when going up wind it turn even further into wind is it the jib to small fin in rong place?
weather helm.
try sheeting jib closer and easing main.
If Brett’s good suggestion isn’t enough to solve the problem, you may need to move the rig forward a bit. Tuning a boat takes a bit of experimentation and time. You will be able to find the right combination if you are patient…of course it also gets easier with experience. Bob Sterne wrote a nice bit on the steps to tune a boat that can be found with some Googling around…I think it might be available on the AMYA site www.modelyacht.org
Bill H
many thannks will give it a go and have a search
right done a few bits to the mast setup,ive moved it bout 10mm forward with a second mast tube but also just added a doule ballbaring setu so its now alot more resposif in the light wind and has realy made a hudge diferance.even had a few races againt my brother which has been good and they seem to be bouth very equal on performnce will try take a vid of the next one and post.
been doing a few outher bits to try and improve it.now given it a larger sail whitch has helped a bit and aslo a litle extra paint to make things a bit more interesting.had a great race this morning but soon as we got the camera out the wind disapeared
sory still cant rotate pics
http://static.rcgroups.com/forums/attachments/1/4/7/5/5/a1628689-246-DSCN5061.JPG
also tried narrowing down a hull to see what it would look like after seeing brets design not to shore what it would be like but i thing it would have to be a fare bit lighter.
http://static.rcgroups.com/forums/attachments/1/4/7/5/5/a1628696-22-DSCN5064.JPG
having problems up loadinging visd but heres a small one from this morning wind was farly light and comeing and going it sounds alot stronger than it actualy was
http://www.youtube.com/v/1Tbl6ebZplE&rel=1