Trevor....... really why can't you accept the industry standards for CF rods being sold today? Man, as soon as I give you the exact modulus of CF being sold for truss rods you start in on this and that, trying to cast doubt on a simple thing. Good fellows science give a standard modulus for CF, at 18, and as I said earlier Jim took the time to get the exact modulus straight from the horses mouth the guy who makes the stuff at Dragon plate.Well, the ebony density doesn't come into this calculation, which you've already been told. As for the CF modulus, like any other manufactured product it's subject to variation in both the design of the composite (intentional) and the variation in the process (unintentional). When you can measure it, why not? Then you know what you've actually got. Even if you use 20Mpsi for the CF modulus, and poke that into Hurd's program, you still only get a ~16% increase in stiffness for a standard config neck.
Like I said Trevor, your numbers are heading up! They have gone up 7% from what you started off with. Now after we place the rod in the most efficient place lets see how much further they climb.
I agree! Jim, has definitely come up with these figures, but he wants to make sure of everything before he shows his calculations....... can you wait a couple more days?Until we see how Jim has calculated these, just quoting numbers means nothing. They're just unsubstantiated numbers.
Trevor, I know you have been trying to create this straw-man, that Jim, or I, are out to prove Hurd wrong, but that's simply not the case. Jim, so far sees nothing wrong with Hurds program other than the fact he uses some bad modulus figures. The way perhaps you should look at this is Jim will ADD to Hurd's program, not prove him wrong.Hurd's analysis and program have been published and available since 2004, if not before, and I'm still waiting for someone to prove it wrong. You put numbers in, you get answers out and for the standard config the answer is the same whatever modulus number you use for the CF composite, namely, it makes barely any difference, because the standard config, using Stewmac CF, has the CF pretty much on the neutral axis. Put the numbers in and see for yourself.
Trevor, you and Hurd obviously have chosen to use the worse possible placement for carbon fibre rods, you use smaller rods than what we use, you managed to get a lower modulus rating on the stuff they sell, and it just seems ur hell bent on coming up with the lowest figures you can to support your claims. Have you even bothered to call stu mac and find out the modulus rating on there CF rods? That might be a good place to start.
However, what is interesting to me, is you now have shifted this whole debate over to what Stu-mac does, quite frankly I've never read their article on CF truss rods, or ever bought a truss rod from them. So this Stu Mac thing is irrelevant to me. What Jim and I, are interested in is the best optimal material and placement of the CF rods to get the best possible results, not this bullshit stuff about what most people do, because Stu-Mac says so.
Trevor, why don't you take a deep breath, and call off the goons, and lets wait until Jim gives us the data.
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If anyone is quoting you a material property number and can't give you the dispersion as well, be worried. Why not just test it, then you know? It's not that hard.