Analysing Masts

[ESP91]

Hello,
I am studying at the Solent university in Southampton (yacht & powercraft design), and I just registered in this forum recently.
I am interested in the performance of the wing masts profiles (not wing sails!), and I would like to know a bit more about there advantages and drawbacks, and especially I am interested in the tests carried out in industry in order to evaluate there effectiveness (wind tunnel, CFD ??...).
Could somebody provide me with a suitable manufacture web sites of wing masts, where I could find wing mast sections, all the other manufacturers such as Selden only provide with standard mast sections.
thanks!!

[Eric Sponberg]

ESP91,

You will likely find very little in the way of standard wingmast sections. The vast majority of wingmasts, such as they are, an extremely small field that it is, are all custom designed and built. Designs are as varied as the individual designers and builders. For reading, get C.A. Marchaj's "Aero-Hydrodynamics of Sailing" to understand the principles of airflow around a sailing rig. To talk to someone first-hand, contact Andy Claughton at Wolfson Institute there in Southampton--he probably knows as much as anyone about the state of the art in research and testing. Very little of any testing or studies in the way of model testing and CFD has made it into the public domain--it is rarely published.

That which is published goes back over 30 years. Here are some technical papers that have been helpful to me, in chronological order:

"Aerodynamics of High-Performance Wing Sails" by J. Otto Scherer, Marine Technology, July 1974. (Marine Technology is the quarterly journal published by The Society of Naval Architects and Marine Engineers (SNAME) here in the US. You may be able to buy copies of these papers from SNAME).

"Wing Sail Versus Soft Rig: An Analysis of the Succesful Little America's Cup Challenge of 1976" by W.S. Bradfield and Suresh Madhaven, presented at the 3rd Chesapeake Sailing Yacht Symposium, Annapolis, MD, January 1977. Sponsored by SNAME who would have copies of the proceedings.

"Effects of Masts on the Aerodynamics of Sail Sections" by Jerome H. Milgram, Marine Technology, January 1978.

"Design and Engineering Aspects of Free-standing Masts and Wingmasts" by Eric W. Sponberg (yours truly), presented at the 6th Chesapeake Sailing Yacht Symposium, Annapolis, MD, January 1983. I have made some corrections to this paper and have it available for free, attached here. Pay attention to the Adendum notes on the last two pages. By the way, I recently donated a copy of this paper to your school library through one of your fellow students who had contacted me directly.

"Wing Masts" by Ted Hugger, Professional Boatbuilder Magazine, Dec/Jan 1992.

There has been much written in the popular yachting press on wingmasts, and I dare say you may run across some of them in your searches. You should also browse this forum some more as there is a lot of other good information to be had. For example, search for postings by Tom Speer who has written well on aerodynamics.

As for builders, any builder with expertise in complicated carbon fiber composites will be able to build a wingmast. The builders will not publish details, but they may offer advice. Builders in France probably have the most experience because they have the most progressive yacht designs, mono- and multihull, that sport wingmasts.

I hope that helps.

Eric

[nico]

http://tspeer.com/

[ESP91]

Thank you very much to Eric and Nico (amazing quick reply)!!!
I wanted to know, if there is any free software out there similar to CFD however simplified for students to start with, such as X-foil?

[Chuck Losness]

Eric,
Thanks for posting your design analysis paper. Interesting reading. My fascination with freestanding wingmasts continues to grow.