Hi Don:
Thanks for the input. I had the articles from this web site, and the procedures are perfectly clear, but still wondering how much should I rise the blocks at the center to obain the ideal curve in the sail airfoil and from foot to top in each sail panel.
I guess it is just a matter of trial an error, but there should be any standar formula to start with.
bes regards
Tato Lazo
hey folks,
I finally got around to building my “Claudio Tool”
here are a few pics. let me know if I screwed up…
I took a 10mm angle aluminum and an drilled three holes one in the middle and two in the outer ends.
I then drilled corresponding holes into the hunk-0-wood all the way through. I then isntalled three blind nuts in the wood. used thumb screws on the outer edges and flat head screw in the center. I then attached the angle aluminum to the edge of the board, and then installed the ruler, which is the same thickness as the angle stock
loosen thumbscrews insert spacers tighten, viola. we got curve…
I figure with the ruler I have a way a “measuring” and repeating stuff…
I made it long enough that maybe I can fool around with my larger sails or luff curves on my footy…
Oh and yes I know my ruler end doesn’t line up with the end of the angle iron. I centered the ruler @ 50 cm and I’ll eventually trim the excess off…my board wasn’t quite one meter long…
Hi:
I finally built my sails with the traidtional block system. It takes some time to achive the correct amount of draft induced to each pannel. I did some practice and the first “legal and valid” attempt is the following picture. No single wrinkle or detail in the sail. The boat runs very fast compared with the same hull.
The cloth used is 0.002" polyester paper, matte both sides, 50 microns.
has anybody found anything new so far?
i found out that gbmy is no longer supply sail matterial… where you getting your stuff
I use TriSpi 40 for my Victoria sails from here:
i used a thin cloth coated in clear spray paint for my sail
I read carefully all the thread because where I live do not have nothing about RC models and if I buy all I need to do a IOM will be very expansive, and I need do my sails.
By this reason, I do my sails with Bantock process, do a curve in the bottom of panel and leave straight the upper part of panel as Sailcut do. I read that Lester say that Bantock do not use this process, but work.
Is difficult, first for need do a curve, for example, with a curvature 1.7 mm with a 0.5 graphite, second glue a straight over a curve. Is difficult and by this reason I search a new process.
The process more in question in this thread, in reality is very similar to the above with a difference, we have a jig to do the two panel union.
When a put the first panel edge accompanying the curved tape I am doing exactly the process above, a straight over a curve. The difference comes now, after making straight the tape and placing the edge of the second panel we have straight end with straight end. When all is released the first curvature is divided between the two panels but I have two straight edges joint, what gives the curvature?
A compound between curved tape and the first panel straight edge being curved on the curved tape, posteriorly forced to be straight? What union type is this? Is stable? With the time the curvature is sustained?
In these both process we have interior stress actuating.
And with the block?
The more easy is better than the more hard-working?
The block introduces much internal stress?
Fred
In regards to using Tyvek house-wrap for sails -
I think the strength and stiffness is great for making the static shape and keeping it, bit IMO, the stuff is much too heavy for sailmaking. I tried a set for my Ocean 500 (slightly smaller than a Victoria, with a short winged keel) and the thing fell over straight away when I put it in the test pool. I was able to weigh the mainsail, which measured 14 grams.
Either Kite Studio/Builder or Hang-em-Hig has a softer “had” ( less stiff ) tyvek. Try Kite builder first… as that is where (I think) I saw the stuff. They advertise as being less stiff/lower weight than house wrap. While some alternative items may be free - they may not translate into good materials for our small boats.
http://www.onemetre.net/build/Sailblok/Sailblok.htm But don’t get too bogged down on Lester’s page!
http://www.myrc.org/ then click on “Library” then on “Sailmaking” The stuff here is more practical than the spreadsheets that explain how it works.
I have also used the plastic that florists use with good results. Being clear, it is hard to see what the sails are doing, but it holds shape well. I have even seen it in colors.
HI hew
I do not knows if you know my Manual, is in italian but plenty of pictures self-explanatory : http://www.nonsolovele.com/Tecniche.shtml >>> “come fare le vele” mean “As to make sails”
3 PDF files can be freely downloaded
Cheers
ClaudioD
A batten question -
what is the opinion/experience of applying battens?
I am playing with some very lightweight scrim based film, and finding problems in attaching thin plastic battens. Any suggestions or experiences appreciated. Didn’t have this issue with prior rip-stop sails using a thin dab of silicone at each end of batten leaving center free. I did use a sticky Dacron patch at each end as secondary adhesion.
Dick
On my ODOM sails, the battens are thin plastic strips attached with clear double-sided tape and a small patch covering each end.
Are there english versions of your sailmaking PDF’s?
Guzz, copy the URL link and paste it into the window at http://translate.google.com
It should translate the entire PDF file, but sometimes the images don’t make it. I leave the original open and the translated version next to it to see the images and the text.
I hope this helps!
I have not seen much discussion about different luff curves and how it helps shape sails, but in many ways, it is as, if not more important than smooth broadseams. How do different sailmakers develop the luff curves that they use, especially for jibs? This is the most “black art” aspect of sailmaking!
No, sorry Guz and thanks to Hew
Right, there is a part of magic that anyone develops
ClaudioD
Claudio-
I never thought of asking this before, but did you ever explain the formula for the wedges?
260 /100 x 0.66 = 1.71 mm
260 is the width of the panel, and 0.66 is the multiplier from the chart, but why divide the chord by 100?
thx
Simply, see the red arrow !!! The Fm (Multiplier factor is a percentage)
The formula for the curve is a secret.
Cheers
Lester explains the division in post #110. You divide the chord by 100 because you are interested in having the maximum draft as a percentage of the chord (9% for example.) You then further adjust that value by the factor. The factor itself is not a percentage. It’s just a number (corresponding to a 9% draft, for example) you use to multiply the first part of the formula to get the correct thickness for the wedges.