C4 NEW BLADES (T700 HT Vgr series)!!!

trux said:

2) T700 - nice to hear it has 40% more tensile resistance, but is it really important at the blades? What exactly was the old material, BTW? And why it was not used before too?

However, if I am not mistaken, high tensile resistance is important at parts with high lengthwise strain, but I do not think anyone tries to tear the blades linearly, so am not sure if it is so important for us. And since higher tensile resistance may also come as trade off of elasticity or fragility, I wonder if you made any breach and strain tests. If so, please let us know the results - the comparison to the old blades would be more than interesting.

Does the high tensile resistance really translates into bigger resistance against blade breaches? Especially in the angle, which I hear (and experienced personally) is a common weak point at C4 blades? Didn't you consider adding more layers on the blade under the foot pocket and at the angle? If I compare C4 blades with for example carbon fins of Beuchat, those are much thicker and stronger under the foot pocket and do not break at that point.

Click to expand...

Hi Trux,
sorry for the delay in me getting back to you.
I prefere to wait my father's answer, not to make mistake in this important matter. ( he was out for work )
Unfortunately he doesn't speak english, so I translate for him.
I'm sorry, if I make languages mistakes, especially for technical words.

T700s is the exactly name of the new carbon fibre we use.
T700 is a TORAY yarn, our older yarn was the T300.
We never used before T700 because it was not avaiable on the market. On the market, almost the total ammount of special yarn produce in all the world are used for Aerospace and Automotive. There isn’t enought production for all.
This is also one of the causes of the great raw materials prices.
In the attached file you can see the details.

The composite blade is made of some layers. When the blade flex, the external layer has a major radius of curvature and it is in tension.The lower layer ( with a minor radius of curvature ) works in compression. The central layer is neutral, it works just in flexion, it hasn’t neither tension nor compression. So it is fundamental that the externals layers have the most resistance possible.
This resistance combine with the material stiffnessis ( modulus elastic ) has to let the blade able to flex.
If we want that the blade flex as we wish, the fibre must have the higher resistance traction value and a standard modulus elastic.
It’s obvious that who hasn’t a minimum mechanical engineering knowledge about the stress of a structure with more layers, can easy make mistakes considering the stress between layer and layer in a carbon piece.

The tests done show that the broken resistance considerably increase, with theoreticals values close by +40%, indicate for the fibre, and this could not be different.
Freediving is not just theory, we can see prodct’s trustworthiness and resistance with a major sample group compared to the laboratory test.
I think that to define a blade reliable, you have to have “under water” 2000 pairs in 2 years.
C4, since it has invented the carbon fins, has produced and sold more than 40.000 pairs of fins, proving that the design and production cycle are highly reliable.

We are updating our web-site, very soon you will find more informations.

Ciao,
Natalia & Marco