STAR 45 CLASS TECHNICAL COMMITTEE Nov. 2006- Dec. 2007

Phil Geren Sat, 25 Nov 2006 20:57:08 EST

STAR 45 CLASS

TECHNICAL COMMITTEE

November 2006 To December 2007

Table of Contents

Origin of this Committee. 3

Charter 3

Membership. 3

Processes. 4

Action Items, prioritized. 5

Origin of this Committee

Don Keeney, Class Secretary of the Star 45 Class of model yachts sanctioned by the American Model Yachting Association, announced at the National Championship Regatta held in October of 2006 that he plans to assist the Membership of the Class in achieving a clear, unambiguous, and uniform interpretation of the Rules. He also stated a goal to enhance the growth of participation in the Class.

To these ends Don formed the Star 45 Class Technical Committee of November 2006 through December 2007. The objectives, members, working processes, an an initial list of prioritized action items are set forth below.

Charter

The Technical Committee shall:

µ Ensure that the Star 45 Class Rules are:

o Capable of being clearly understood by all Class members without ambiguity;

o Subject to only one interpretation;

o Adequate to preserve the one-design principle of the Class, while allowing room for improvement in sailing performance

By:

o Formulating and publishing Guidelines for Rule Interpretation and Application (“GRI”);

o Submitting to the Class Secretary proposed Rule Amendments and New Rules;

µ Enhance growth in Class Membership by:

o Discovering and publishing corrections and clarifications to errors and ambiguities in the approved Star 45 reference and construction plans;

o Discovering and publishing Guidelines For Building And Tuning (“GBT”) Star 45 Model Yachts in order to assist a builder in achieving a competitive racing boat, at minimum cost, complying with the Rules, regardless whether building from scratch or from kit materials.

Membership

The Technical Committee shall comprise eight participants: the Class Secretary, Committee Chairman, and six Members. The Committee Chairman and the Members shall have voting rights.

The following people shall be directly involved in the business of the Technical Committee:

Class Secretary: shall participate in all discussions; shall take the final decision on all issues regarding the Rules after receiving the recommendation of the Committee. shall have no vote in Committee voting processes; shall, subject to his sole discretion, publish Guidelines for Rule Interpretation and Application received from the Technical Committee; shall, subject to his sole discretion, submit to the Class Membership for approval Rule Amendments and New Rules received from the Technical Committee;

Committee Chairman: shall recruit to fill vacancies on the Committee; shall chair discussions among Committee Members and administer voting processes; shall have voting rights; shall prepare the final wording of GRIs and GBTs based upon the consensus of the Committee; shall publish GBTs;

Committee Members: shall bring issues to the Committee for action; shall discuss and reach consensus, through simple majority vote on all issues; shall formulate Guidelines for Rule Interpretation and Application and submit these to the Committee Chairman for preparation of a final document; shall formulate, prepare, achieve consensus upon and submit to the Committee Chairman Guidelines For Building And Tuning Star 45 Model Yachts.

Present Committee Membership:

Class Secretary: Don Keeney, 1keyknee@281.com

Committee Chairman: Phil Geren, philgeren@aol.com

John Fisher, racer577@citystar.com

Dave Mainwaring, mainwaring@rcn.com

David Ramos, david@rcyachts.com

Peter Latournes, platournes@aol.com

Mel Holman, foxnlox@buckeye-express.com

Region 3 Candidate - being recruited

Processes

µ Discussion shall take place through postings of Email messages to:

star45technicalcommittee@mainzone.com

or messages posted while visiting this website:

http://mainzone.com/cgi/lyris.pl?enjter=star45technicalcommittee .

Posted messages are read at: http://mainzone.com/cgi/lyris.pl?enjter=star45technicalcommittee .

Please note that photos and attachments cannot be sent to the above.

Photos and attachments can be sent to: http://star-45.blogspot.com/ , where building information is being archived.

µ Consensus shall be by simple majority vote;

µ The quorum shall be the Committee Chairman plus 4 or 6 Members;

µ Guidelines for Rule Interpretation and Application shall be published by the Class Secretary as he sees fit;

µ Guidelines For Building And Tuning Star 45 Model Yachts shall be published at Star 45@yahoogroups.com , at star45houston.com , and at http://star-45.blogspot.com/ .

µ Preliminary performance targets for the Committee are to:

§ issue this Technical Committee organizational document for voting by the Committee on 26 November 2006;

§ issue one GRI per month;

§ issue the first GBT within three months.

Action Items, prioritized

1. Guidelines for Rule Interpretation and Application:

a. overhang of backstay chainplate, strut, boomkin or other device – how to measure

b. “hull” definition, wood, fiberglass

c. 1/4” or 3/8” bow bumper overhang

d. rudder profile and dimension limitations

e. jib numbering

f. obtain reference and constructing drawings additionally from Class Secretary (not just Ship’s Store)

g. fiberglass = fiber reinforced plastic, such as glass or other fiber cloth impregnated with hardened epoxy or polyester resin

h. Rule 1.4: rule to be waived if unable to be reasonably applied, such as, for example, if the deck or keel is attached, if verification by another Class member is inconvenient (requiring mailing the model, for example). Alternatively, Rule 1.4 to be deleted.

i. Hierarchy between Rules and Drawings

2. Guidelines For Building And Tuning Star 45 Model Yachts

a. Make available the best of the versions of the laser-cut frame files with instructions, online

b. Discuss if http://star-45.blogspot.com/ organization is the optimum for guiding beginners

c. Keel and bulb locations

d. Wings on rudders and bulbs

e. Glue recommendations

f. New building materials

g. New sources for woods, other materials

h. Jib tweakers

i. Jib twitchers

j. Drawings, correctd on CD

k. Camber recommendations for keels and rudders

l. Backstay tension calibrated for mast bend

m. Mast bend recommendations vs wind speed vs luff curve

n. Sheeting angles vs windspeed

o. Mast position vs wind speed

Curved mast -- tuning a mainsail

From: Philgeren@aol.com
Sender: Star45@yahoogroups.com
Date: Wed, 22 Nov 2006 06:58:53 EST
Subject: Re: [Star45] Curved mast -- advantage ??


Curving a mast so that it bends convex forward (concave aft) moves the luff edge of the sail forward and reduces the camber of the sail in the section where the mast is bent (if bent half way up the mast, the camber in the up/down center of the luff of the sail is reduced). In a blow, this reduces power, reduces leeway force, reduces weather helm, allows the boat to increase its speed.

Generally, the minimum position of mast bend is considered to be a curve equal to the luff curve designed into the luff edge of the mainsail. For very light air and for heavy air, maximum mast bend is used for maximum speed. For very light air, less camber makes it easier for air to stay attached to the leeward surface of the mainsail as the air passes aft. For medium air and for waves, where maximum power equates to maximum speed, minimum mast bend is used to get maximum designed camber.


By use of all the tuning controls on a mainsail, one can obtain a certain amount of control over the distribution of camber over the length of the mast, and there will be an optimum camber distribution for any particular sail and set of wind conditions. Pretty complicated to get it perfect, however outstanding sailors like Stuart Walker are on record as saying it is of paramount importance to use this against competitors who are using it. Otherwise, in a one-design competition they win.
My two cents.

A great place to learn about sail trim.

From: "Don Keeney" <1keyknee@281.com>
Date: Sun, 19 Nov 2006 15:39:26 -0600
Subject: [Star45] Sail Trim

A great place to learn about sail trim.
http://www.sailingusa.info/sail_trim.htm

Don Keeney
Star 45 Class Secretary

--

Outstanding recommendation. Wonderful site. full of photographs and all sorts of instructional materials. Pictures of tells and how to read them:)
--

Also a must place to visit and test your sailing skills:

National Geographics Interactive Sailing:

Master rudder and sail to get your boat going as fast as possible no matter what direction you're sailing in-or which way the wind's blowing.
Controls available:

Sail Adjuster: Use the left sliding controller to rotate the sail in relation to shifting wind (shown as arrows). When you cross the path of the wind, your sail will swing to the opposite side.

Rudder Adjuster: Using the right sliding controller, steer to port (left) or starboard (right).


Uncle Dave

Star 45 Construction ply sides and a cedar strip planked bottom

From: "John Fisher"

Here is my dad putting the sides on his boat. This method could be done with balsa as well if someone has an issue with CA. The clips he uses can be purchased at any office supply store.

His boat is going to have ply sides and a cedar strip planked bottom. I made him a set of frames with 1/16 cut on the sides and 1/8 cut on the bottom for this application.

Using 1/16 inch plywood for sides

I use Titebond glue instead of CA. I first clamp a 4" by 48"
piece of the plywood against the framework on the building board. I then trace around the profile of the side to outline the approximate size and shape of the plank. Using a knife, I cut around the outline to remove excess plywood leaving about a half inch extra. This should be sufficient to allow the clamps to grab the stringers along the rail and the chine. I then apply Titebond on the stringers and clamp the plywood
in place starting in the middle and working to the ends. I used about 40 clamps to ensure a tight seal (2679).

I trim the plywood back to about a 1/16 of an inch above the balsa stringer using a Stanley modeling plane (2681). These cost about $10 at Ace Hardware or any home warehouse. This takes about 5 minutes and then I use sandpaper to finish the trimming.

Star 45 Construction splicing wood to get longer pieces

John Fisher writes:
Since 48 inch balsa is hard to find, I used 1½ pieces of 36 inch balsa that I joined using a 45 degree scarf. I cut a small (about 1 inch long) piece of the balsa I'm joining as a support for the joint, both structural and for alignment. 2668 shows the three pieces before gluing. I use titebond rather than CA because I'm sensitive to CA. I clamp the three pieces as shown in 2669 using the table top and the small piece to gain alignment in both directions for the two long piece. During construction the small piece of balsa must be placed where it doesn't interfere with the construction (2673). Once the stringer is glued to another piece of planking or another stringer the small piece can be removed using an Exacto knife and sandpaper

S45 Construction radio tray as a built in component to the hull.

From: racer577@citystar.com

I am building a new boat and incorperating a few new ideas. One is to
include the radio tray as a built in component to the hull. I added two
1/16 plywood plates that are notched to fit into the frames. This
particular one is designed to hold one servo and a RMG winch. I will see
how this works out. The down side is going to be limited access, but the
up side is light weight and strength.

If there is interest I may build this up for other winch options.

John

S45 Construction Rigging photos from John Fisher

Subject: Star 45 deck rigging

Here are some rigging photo's. Back stay fitting,
jib lead that I used, note that it holds the line off center so
it doesn't get caught in the mast jack, Another shows the notch I
put in the mast so I could put the sail on and the crane that I used,
and another shows my mast jack and vang. Plus a photo of my deck layout on
812.

John

S45 Construction rudders on #812 and #813

From John Fisher:
Here are the two rudder examples, 812 is the thicker one and 813 is thinner. The % thickness is the same on both, but 812 is thicker over more of the rudder since it was a 1/8" pc of balsa that was rounded on the ends. 813 was made by two pcs of 1/64 ply expanded over a 1/8" shaft.

They clearly show the difference in cross section, however they’re a little small to judge the details. Interested in contrasting the radius of the leading edge. Is there much of a difference between the two rudders in the first .125 to .25 of the foil? Typically sections with a sharp leading edge will lead to a pronounced stall as the flow can’t make the sharp turn to stay attached to the low pressure side.