Was Marchaj having us on?

I think you are "ducking the question". You based your argument on the factual estimate of 25% and are now" doubling down" with:

All I'm asking for is a reference to one of these published numbers from wind tunnel sources. If there are plenty of them, please, provide one.

 

A quite extensive paper by Fossati et al ('An investigation of aerodynamic force modelling for IMS rule using wind tunel techniques') published in 2006 provides a thorough review.

The paper's outputs for non overlapping jib IMS yacht @ 22 degrees AWA has side/ forward ratios in the range 0.19 to 0.32.

I will try to find the North output (which, iirc) had 0.236 for a genoa without mainsail, from last century though.

 

Thanks for that, I'll read it.
BTW the et al includes one Ignazio Viola with whom I had a spirited exchange of ideas last year about a paper and video he had posted on the web site of the University of Edinburgh. I had challenged his revolutionary concept of vortex theory to generate lift. Shortly thereafter both the paper and the video disappeared from the web site. Draw your own conclusions.

Please do. I spent many hours researching and referencing the sources in my paper.

 

I have opened it. It is very long (35 pages) and very detailed. Can you point me to the reference page please?

 

Al
Try the graph at Section 2.5, Figure 5.

It has all the outputs for 22 degrees AWA, I think with and without hull and spar windage. The data is for a non overlapping headsail.

As one other reference the vpp for a Farr 40 has optimum AWA in the range 22 to 24 degrees up to the first point of maximum heel.

Cheers

 

Nice one, thanks.
It was an interesting experiment.
It seems they were directly measuring the size of the aerodynamic force with a pair of strain gauges mounted orthogonally on the boat and then combined their values as vectors into a single force vector. They then mathematically resolved the force vector into the boat's centreline to arrive at the Fx and Fy values, and then converted them to Cx and Cy.
Thanks.
But I'm still not sure why you mentioned the number.

Yes, I know, I race a Farr 40.

 

Sailor Al has many posts where he expresses his misunderstanding of basic concepts. When at a loss, he often posts and opinion or what he imagines it should be. However, with no basis in any documentation. For example, claims that there is no experimental of theoretical explanations to refute his claims. He has zero credibility.

 

What's the problem with that?
A theory will remain valid whilst it explains problems and can predict outcomes, and until it is refuted by logic or experiment.
Newton's Laws remained valid for all objects in human experience until Einstein.
Even then he didn't refute them, but refined them to deal with phenomena beyond human experience.
I think that counts as trolling.

 

Newton's Laws remain valid today, within their limits; same as Einstein's theories. Neither has been refuted. They have been found to have limitations.

 

As I said, Newton's laws apply to human experience. Einstein extended them to realms beyond human experience, light speed, massive objects, immense distances, sub-atomic distances.
I think you are simply paraphrasing my reply.

 

Not at all. Einstein explained relativity using a train and passengers as an example. That is definitely within the human experience.

 

Einstein's Theory that lead to posit the Big Bang Theory is actually under attack right now.

-Will

 

Don't be silly.

 

You mean don't be as silly as a theory of gravity that says bodies of mass accelerate towards each other because space and time are warped by their existence and that it is because our future is to occupy the same space and time, that causes us to experience such a "non-force" of attraction?

Is that what you mean?

This is the same theory that posits all existence out of a singularity of infinite density that led to a great explosion of mass that even 14 billion years later, is still accelerating away from that singular point of spacetime?

Are you saying I shouldn't be that silly?

 

No. I'm saying that your suggestion that Einstein's theory is under attack, is silly.