Mast Drag Info

by **PaulP** » Sat Nov 06, 2004 7:43 pm

Help me with another memory problem

Somewhere, I recall seeing a comparison of the teardrop shaped mast with a round mast. The round mast proved less drag under certain conditions, the teardrop on others. As I recall, there were some illustrations with the discussion.

I've looked thru the manuals (both of them) and thru Tom Widdens book but can't find the info.

Does anyone else recall the location of this info?

Paul P

by **s vernon** » Sun Nov 07, 2004 12:11 am

Paul,

Manual page 23? Some discussion but probably not what you are looking for.

Scott

by **PegLeg** » Sun Dec 05, 2004 10:41 pm

I seem to recall that there was a paper available on the net from England. I think the man's name is Gilbert. Anyway you should be able to search the web through some of the English sailing sites. As I recall it was a very good treatise on the subject. Gilbert? also has many other interesting papers on R/C sailing. Well worth the effort to find his stuff.
Good Luck[}:)]

by **IanHB** » Mon Dec 06, 2004 12:27 am

Here is the site you are looking for. Full of interesting stuff about model yachts of all shapes and sizes.
http://onemetre.net/

DO IT NOW, Before it`s to late

by **kermwood** » Sat Mar 19, 2005 3:58 am

Is anybody out there using round mast section,if so what diameter are you using.As l have so far been unable to source a supplier of goldspar here in the uk. l Have been looking at bantock groovy mast section instead.l have come up with two poss selections

14.5mm - 0.75 wall thickness -95grams a metre
12.7mm - 0.60 wall thickness -70grams a metre

Now whilst l want strengh l want to keep rig a light as poss,any suggestions on any of the above or observations. .
Woody

by **Doug Wotring** » Sat Mar 19, 2005 10:14 am

I think that 14.5mm is a bit too large for a 12

by **yachtie** » Sat Mar 19, 2005 6:15 pm

Woody - have you looked for the Cap Maquettes range - they have 3 different section sizes in groovy teardrop. Made in France and what a few of us down here use.

Also LOADS of blocks and other gear available.

Their web is www.cap-maquettes.com/ - but if you click on the flags you get an English site and catalogue.

Chris
NZL1 Longtack
&
NZL110 Swept Away

by **kermwood** » Mon Mar 21, 2005 4:06 am

Thanks for info Chris,Cap Maquettes rep belongs to my club!
Stopped inporting mast section sometime ago due to shipments of section always arrived damaged.(would have thought they could solve that problem).So because of problems returning damaged goods he won,t inport it any more
Woody

by **PegLeg** » Thu Mar 24, 2005 9:45 am

Try Larry Ludwig - Ludwig Manufacturing here in the US. He has just retooled the teardrop mast. Give him an email at
LindandLarry@satx.rr.com

Pete

by **Larry Ludwig** » Thu Mar 24, 2005 6:55 pm

did somebody pull my string? You betcha, we have them in stock and ready to ship. They come in 8' sections but we can cut it down to 6' and 2' boom and they ship a lot cheaper. We also have the mast fittings almost most finished. MastHead, mast foot, and boom end are completed, the gooseneck plastic molding is complete but we are hung up on the ball stud and friction slide... and it is making me
nuts.[xx(]

You can see the spars on the website under Accesories Spars Aluminum.
The 6' section weighs 4.6 oz.

www.LudwigRCYachts.com

Thanks Pete![:D]

by **Kelly Martin** » Sat Apr 30, 2005 3:20 pm

Larry Robinson tested the teardrop shape versus round shape for drag back in the early 90's. He found that the teardrop had less drag than the round section when the apparent wind was 31 degrees or lower. The round section had less drag when the apparent wind was over 31 degrees. More information, including stiffness comparisons, is included in The Manual for the East Coast 12-Meter by Robinson and Wells.

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by PaulP</i>

Help me with another memory problem

Somewhere, I recall seeing a comparison of the teardrop shaped mast with a round mast. The round mast proved less drag under certain conditions, the teardrop on others. As I recall, there were some illustrations with the discussion.

I've looked thru the manuals (both of them) and thru Tom Widdens book but can't find the info.

Does anyone else recall the location of this info?

Paul P
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Kelly Martin
Rocket 3

by **kahle67** » Sat Apr 30, 2005 11:17 pm

Larry,

I can only access the home page on your site. Am I missing something?

Reichard Kahle
1767

by **Gene Rosson** » Mon May 02, 2005 10:37 pm

Have lots of experience with sailing dinghys. Full size, get your behind wet types. Here is the low down from real world results. The round mast is very satisfactory with a sleeve luff such as Laser. If the sail is attached to the mast via track or groove the boat does not go to windward very well. The sail is fixed with respect to the mast. BUT, if the mast can be rotated so that the sail luff is moved to the leeward side the boat takes off.
Grab your pencil and doodle the section view (horizontal slice)of the mast/sail in fixed position and then in rotated position. Big difference in foil shape.

Not likely that we can use a sleeve luff on an EC12 but we might jigger up a rotating mast. Loose shrouds, trick gooseneck with rotation limiter as used on cats, Moth and other go fast boats. Am I getting into rules violations here ? I'm an absolute novice EC12 person but have lots of technical info to share from big boats.

by **Capt. Flak** » Tue May 03, 2005 12:32 am

Sorry Gene, Rotating masts are not permitted.

Joe Walter #24

Mast Drag Info

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