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Re: T-Belly G6

Posted: Sun May 05, 2019 5:46 pm
by asier esnal
I know that the paipos get longer to avoid the less leg drag. but on the other hand, this is a fight with the turns that you have a hard time doing, I understand that it is com to want to make a bottom on a 9.4 longboard in the same radius as a 5.8 surfboard.
so why not stay at 45 or 46 as much? those are the ideas that do not fit me in the head, 52?

es

se que los paipos se hacen más largos para evitar el less leg drag. pero por otra parte, esta una pelea con los giros que os cuesta mucho hacerlos, entiendo que es com querer hacer un bottom en un longboard 9.4 en el mismo radio que una surfboard 5.8.
entonces por que no quedarse en 45 o 46 como mucho? esa son las ideas que no me terminan de encajar en la cabeza. 52?

Re: T-Belly G6

Posted: Sun May 05, 2019 6:01 pm
by nomastomas
Prone boards turn off the rear corner. My guess is that turning a prone board is more about rail shape,outline shape and presence or absence of fins than length.

Re: T-Belly G6

Posted: Sun May 05, 2019 7:04 pm
by rodndtube
Boards do not have to get too long to be legs free during riding. Much of the time my legs are bent up at the knee at a 90 degree angle, more or less. It is also true the legs had be used as an additional turning keel, at times, and at other times with the right kind of swim fins the leg extension can extend the planning surface or capturing the rear energy of the wave (my flat plane Viper fins are better at that than my bent angle DaFin blades).

And I agree that most turning is off the rear corners (and skegs), but I also do a fair amount of turning on the front rail section of my board (one reason I don't like my front rail too edgy or skinny or turned under nor too rockered).

Re: T-Belly G6

Posted: Sun May 05, 2019 7:37 pm
by nomastomas
I agree that extended legs can and do extend the "wetted surface". But that "extended surface" creates a lot more drag than the form drag of the hull. Its that extra drag of the legs and swim fins that can be used to control direction, much like dragging an oar in a canoe. Taken to the extreme we have the handplane.

Re: T-Belly G6

Posted: Mon May 06, 2019 3:59 am
by krusher74
asier esnal wrote:according to those bodyboard measurements, I do not understand why the paipos are made as big, 49 and 52 as you comment in the first post?
What is the overdose that is compared to 42 of the bodyboard?
my paipos are 43/44 x 18.5... 20 max inch and I measure 1.75cm weight 75kg
My own paipos are 43", (which is just a 42" bodyboard with an extra inch of pointy nose) 18.5, however, is very narrow for a bodyboard. A 42" would normally be 20/22" wide. (my latest summer board is 22 3/4 " wide") that works out at over a square foot more planing area, A 20% difference. pretty significant.

Re: T-Belly G6

Posted: Mon May 06, 2019 5:43 am
by asier esnal
The width of the board, in my opinion, depends a lot on the shape of the wave, vertical waves, narrow board, flabby waves, wide board. the boards that I made are for winter waves with hard waves or days of wind with choppy waves, for these my humble experience 18.5 is a good size, facing the summer I will make a wider 20/21

Re: T-Belly G6

Posted: Mon May 06, 2019 11:16 am
by rodndtube
nomastomas wrote:I agree that extended legs can and do extend the "wetted surface". But that "extended surface" creates a lot more drag than the form drag of the hull. Its that extra drag of the legs and swim fins that can be used to control direction, much like dragging an oar in a canoe. Taken to the extreme we have the handplane.
The benefit, however, is extended surface (and subsurface) flexibility on-demand. I can't swap out hull form boards in the middle of a wave! In direct relation, when riding my Xylem wood paipo which has near neutral buoyancy, I catch waves with the board extended out in front of me... a far better option than riding a buoyant alaia length board where I could not kick paddle.

And, of course, being on a relatively short board (50 inches) with knees bent and legs out of the water.

No, I don't want a hand plane ;) Heaven forbid you did not suggest a surf mat 8-)
<Joking>

Re: T-Belly G6

Posted: Mon May 06, 2019 11:35 am
by GeoffreyLevens
"The benefit, however, is extended surface (and subsurface) flexibility on-demand. I can't swap out hull form boards in the middle of a wave!"

Uh-oh, an advertisement for surfmats ;)

Re: T-Belly G6

Posted: Mon May 06, 2019 12:11 pm
by nomastomas
rodndtube wrote:I can't swap out hull form boards in the middle of a wave!
If the hull is the appropriate length and volume for the riders height and body weight, there is no need. One simply lowers the leg(s) if added drag is desired, or raises them for maximum planing efficiency, all the while maintaining a position on the deck that maximizes kick-paddling efficiency and planing efficiency. Obviously, if one strays from the "appropriate" length/volume prescription, then one will have to adapt riding style accordingly, e.g. move back and forth on the deck on a shape that is too long, get off the deck entirely on a shape that lacks buoyancy, or adjust the air pressure to increase/decrease buoyancy in the case of our "matted" friends. I prefer the less complicated approach that comes from having a shape that fits, both the rider and the conditions it is to be used in.
It may be that the G6 under development is, at 21.75", still too wide for its intended use. Only further testing will answer that question. But I believe the length at 52" is very close to optimal (for a person my height).

Re: T-Belly G6

Posted: Tue May 14, 2019 11:23 am
by belly rider
Man this is intense reading and requires a few reading rounds of the same post to grasp it all and try and draw conclusions and develop our thoughts It is very interesting reading through

Re: T-Belly G6

Posted: Fri May 17, 2019 8:24 pm
by nomastomas
The G6 arrived from Marko today, and I got a chance to hold it in my hands. I'M STOKED!! Photos tomorrow after I scrub it and fine tune it a bit.

Re: T-Belly G6

Posted: Sat May 18, 2019 6:01 pm
by nomastomas
Finished the G6 today. Can't wait to get it glassed. Unlike it's predecessors, the bottom is flat, rail-to-rail in the mid-section instead of concave. This was a de-tuning of the bottom to reduce lift. Same convex nose and V tail, with dual exit concaves as the other TBs. This will be a quad fin and the trailing edge of the front fin will be adjacent to the wing in the outline.

Re: T-Belly G6

Posted: Tue Jul 02, 2019 11:44 pm
by nomastomas
Gloss coat was sanded today and I snapped a few photos before heading to the beach for a test run.

Re: T-Belly G6

Posted: Tue Jul 02, 2019 11:46 pm
by nomastomas
A few more....

Re: T-Belly G6

Posted: Wed Jul 03, 2019 12:00 am
by nomastomas
Extremely happy with the performance, even though the choppy, chest-high, late-afternoon session was far from the conditions the G6 is designed for. I was way over-finned with 5.1" rears and 4.7" fronts, and in these conditions with these fins, the G6 was a notch slower than the G5. But interestingly, much, much smoother, especially on take-off. With the G5, the take-offs are either off or on, with this sudden, almost explosive burst of speed. The G6 is much more mellow, "controlled", can't find the right word...Haven't had enough time to really think this through, nor enough experience with larger waves and/or smaller fins. With swell from Cat 5 Hurricane Barbara on the way up from Mexico, there should be time for both.

Re: T-Belly G6

Posted: Fri Jul 05, 2019 5:00 pm
by bgreen
How thick is this board? I have a new double concave - I'll post some photos up in a separate thread. Interesting to see we both started ata Goddard style board and have gone in divergent paths.

Re: T-Belly G6

Posted: Sat Jul 06, 2019 1:04 am
by nomastomas
With a deep deck concave and shallow bottom concave the G6 is 1.75" thick at the centerline and 2.25" thick out at 2.5" in from the rail. This configuration gives the TBs an "I-Beam" cross section which serves to eliminate flex (the enemy of speed), while making the deck more rider-friendly and adding a little bit of lift to the bottom. It's important to recognize that design features create multiple effects. And, that these effects can be integrated or in conflict. I've spoken before about the need to achieve a balanced design.
Yes, for me the wide-point back outline and a similar thickness flow is about all that is left from the Goddard influence. Although, I like to believe that I employ a similar systematic approach to design that was heavily influenced by LG's meticulous work.

Re: T-Belly G6

Posted: Sun Jul 07, 2019 3:29 am
by bgreen
The thickness flow of my boards keeps changing - its now more evenly distributed than Larry's original. Also a bit more tail lift., though less than a standard board.

Re: T-Belly G6

Posted: Sun Jul 07, 2019 6:04 am
by CHRISPI
The rail and trailing edge are looking good, I found a wide square trailing edge generally very fast, but dropping down a vertical face they make the center of lift move to the outside tail making the rider move back to control the pitch, dragging more bits in the water.

Re: T-Belly G6

Posted: Sun Jul 07, 2019 10:52 am
by nomastomas
That's interesting...I've never experienced that. It may be that the dual "exit concaves" I place on the bottom are doing their job and relieving the pressure beneath the tail, eliminating excess lift in this area. Lindsay Lord discuss this phenomenon in his book and which inspired Bob Simmons to incorporate a single exit concave in his shapes, which is where I got the idea. "Standing on the shoulders of giants..."