Questions for Quad Riders ........

[willli]

A question:

given all the subjective responses (including my own)

what if you don't feel boost cos the acceleration curves you feel are very smooth, like the principal question on your mind when riding is "How do I slow this thing down?" As was stated earlier, my Blast fish hops up to speed on takeoff as well, and when things look to be shutting down, grab a rail and pull in and on occasion make standups weep with envy.

My Flashpoint thruster (excluded) is so responsive and always delivers speed and acceleration when I ask, to the point of rides ending with me actually disoriented from the pleasure of the experience. Were I primitive in thought I'd burn the thing as full of witchcraft.

hope all this boost stuff works out.

[zorro]

Willli

what if you don't feel boost cos the acceleration curves you feel are very smooth, like the principal question on your mind when riding is "How do I slow this thing down?"

good point Willli.

But if you never change parameters on the same board, how will you ever know?

I guess I base my subjective observations on a "known" quantity and change as few parameters as possible and see what the difference is.

EG: Brewer did it by chopping tails off the same board and watching the consequence. But he also moved the fin each time.
Mctvish did it with his assymetrical designs by chopping one side of the tail out and changing fin assymetry in distance from the stringer on the same board.

In this case (not that I'm Brewer nor McTavish- they're much older than me for a start ) I changed from tri to quad on the same board.
So that is my comparison set. Tri to quad.
I also changed the longitudinal seperation in the quad.
Also the base of the fins.
Also the size type and flex of the fins.

But I didn't change the distance of the fins from the stringer.

Some setups gave the quad boost. Some did not it. Each setup was as fast as each other during normal turns etc:idea:

Willli also said:

hope all this boost stuff works out.

thanks mate.

Guess this thread has run its race.

Thanks to all those who participated in this thread

cheers for now.

Out of interest, had a surf with three quad riders today.
When I mentioned this subject none of them knew what I was talking about

[john -]

Zorro

dont be put off by the....."whats the word" ah...does'nt matter


surfed some full but clean 1 to 2 footers today...pretty crap

moved breaks by 2 car parks and picked up 3 great 2 foot waves including a tube

point of the brag

Gary (Finger) and iI watched twin finers go at on FRIDAY...ONE WAS PRETTY GOOD....but on sectioning waves their was no drive to catch the face

on the quad I had less difficulty in getting around section cos I get that squirt

today the same...small waves made to be so much more cos of that squeeze up a gear feeling when racing along a beach just about shore break section

loose cos there is no center fin but drive cos of the water squeeze

but then again, the subjective, isnt that why some people wank

[fooj]

Z
Never had a reason to mess with fins on my Blasts, the boards are fast enough and very dialed in as they are. Riding adjustments are made by me, some say that's wrong but why chase a rainbow when you are the pot of gold? Though I do change my Stubb's trailers to "popsicle sticks" when it is really really small, and ride it flipperless sans railgrabbing.

[Smokin Rock]

metaphorically speaking

waves are like women
there are tall ones, short ones, fat ones, ugly ones and amazingly beautiful ones.
surfboards are like mattresses
if you have a amazingly beautiful woman in your bed then you would never think about it (mattress) nor would it matter whether it was old and tattered or brand spanking new. (oops, i said "spanking" settle down bruce)
if on the other hand the girl was ugly and fat then the mattress could offer some consolence if it was of high quality. a good nites sleep and all.
my thesis is we should concetrate on getting beautiful women into bed, not what mattress we bed them on.

[skansand]

thats great...and sometimes the women totally reject you and wont let you ride them at all..

[fooj]

Eh mattress guy, I heard Big Island was bad with the chicks (dreads and no mo' teeth) but I neva realize was dat bad.

[hart]

just before this thread is disintegrated by the 'Hawaiian Eyes' (I mean guys..)

Headwax (sorry not to blow your cover )

I got the Sunday Papers and there was an article about the Red Baron and a subsequent piece about his undoing..the Sopwith Camel

It was of course, about Triplane Vs Biplane (aerodynamics)

Early aeroplane dynamics relied upon multiple wings that generated 'boost' between each wing, purely to get them off the
ground..initially

No doubt whatsoever, that 'boost' occurs in this multiple-wing situation..and indeed, was absolutely necessary in those early aeroplanes

But we certainly don't see this wing configuration in modern aerodynamics at all..in fact, we see the opposite



Air does compress to give advantage at times (even though aerodynamic engineers gave up on the idea c 1919)

And yet we also know that water does not



(compress, that is)

hart

Nothing ever comes for free

If you're feeling something..I reckon it has cost you somewhere else

[Smokin Rock]

Bruce,
my metaphoric essay was meant as a strictly somber realization of the juxtaposition of so many of the crucial elements and their inherent relationships to one another. or something along those lines.
to insinuate that we were trying to disintergrate this heady mishmash of surfing science is simply not the case.
zorro = headwax! no way!
fooj,
you are a married man and your subtle attempts to get me to hook you up with those vivacious puna girls are falling on deaf ears.

[john -]

:
Nothing ever comes for free

If you're feeling something..I reckon it has cost you somewhere else

Now there is an interesting observation bruce and probably quite right...but I guess it comes down to where one wants to pay for it on a particular board and/or thought

Im still interested in knowing at what stage Dave Parkes swaps from a quad to a thruster during the north shore gathering in 05

we see him mostly on the Friar Tuck swallow tail quad

but Simon mentioned that he was also on a thruster after I noted his cover to the DVD NS05, featured two quad riders (Parkes and Baden) and only one Tri/Thruster being Simon himself

a plus for the quad riders of the world I thought


now of course my "humble in surfing ability self" swaps from quad to thruster for larger surf...but that has more to do with board shape than fin payment


but if I was great surfer im sure it would be..."...money for nothin and the chicks for free....!)

[zorro]

this post edited because of verbosity

Hart wrote:

Air does compress to give advantage at times (even though aerodynamic engineers gave up on the idea c 1919)

And yet we also know that water does not

And yet when I sit in the lineup and look around at the water around me, what do I see.

Aerated water. see ref1



But seriously, though you've heard it from me in the past, I don't think anyone in this thread has spoken about compressing anything. Perhaps some of the references have, yet they have been provided as an example of tradional thinking with regards to the "slot effect".

In this thread I'm not saying that quad's compress water, nor that they have some kind of ramjet effect.

In fact, from one fellows research with sails, it would suggest that the water in between the fins is actually moving slower than the water outside the fins.

From his research you might also conclude (erroneously or not: see ref2 ) that, in an ideal quad setup, the fins are acting on each other in such a way as to accelerate the water along the inside edge of the back fin.

• If we have a situation where water is being accelerated along one side of a fin (the inside edge), so that it is travelling faster than water on the outsdie of the fin then we will have a situation where the fin will want to turn away from its inside edge.

This is the boost I am speaking of. It combines with the other characteristics/advantages of having the fin cluster working in unison, rather than antagonistically.

For me it happens in the turn, not in the straight. It doesn't make my board track, it doesn't send me flying over the wave, all it does is suddenly increase the drive resulting in added acceleration - something I've never felt in all the years I've ridden a tri fin or a single fin or a twin fin.

Hart doth wroted quite rightly:

Nothing ever comes for free

If you're feeling something..I reckon it has cost you somewhere else

No-one's claiming that we are getting something free here.

Quite the opposite

By designing our quads around their ihnerent strengths we are trying to harness the available energy in the best possible way.


Cheers:

1) http://www.mpl.ucsd.edu/people/deane/re ... lecam.html
2) http://web.princeton.edu/sites/writing/ ... reason.htm

[KenM]

After that one I think I'd like to change my vote: El Zorro esta de sus tuercas.
All kidding aside, I'm thinking maybe you should get a copy of the book "Naval Archetecture of Planing Hulls" by Lindsay Lord. I was just reading about Bob Simmons in an old Surfer's Journal and it said this book had a big influence on him.Might be right up your ally. $90.00 on amazon.com.Happy reading.

[zorro]

KenM

Sorry about that.
I accidently slipped on the keyboard and wrote a small book.
Thanks for the reference. Always good to have reading available!

Should have said:

1)Though we are surfing on a mixture of air and water,
2)Presently Quad "boost" isn't claiming to compress air nor water, nor does it mention the 'venturi' word.
3)The effect might exist, if it exists, because of water speedup along inside edge of the back fin.
4) Not claiming to get something for nothing, merely to utilise what we already have.
Finally: 5) I am not inspector Closeau.

[KenM]

Now how about an essay on quads with single foil forward fins and full foil back fins.

[zorro]

Thanks for the refv KenM

Interestingly traditional sails have an inner concave surface .... sounding familiar with latest fin design?

http://cetic.swan.ac.uk/surfs/pdf_files/ASR%20Paper.pdf

interesting ot article on glassed in fins versus boxed fins, and drag.

Seems the rovings cause more lift.

great pics at the end too

have edited that other post