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Voidhawk9

A different 3" spar tape - usable?

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I have bought some 3" uni tape from France, believed to have been intended for someone's canard project, but never used. It is a bit different to the 'usual' heavy stuff.  See photo for side-by-side comparison.

post-168775-0-79063900-1520203306_thumb.jpg

 

I have enough of the usual tape for a canard, and enough of the lighter tape for an entire cozy (estimated by weight).

There are more cross-threads, and they do not seem to be readily removeable.

Obviously being a lighter / thinner tape, I'd need more layers to fill the troughs.

 

Can anyone advise on whether this tape is a good substitute? Perhaps this stuff has been used by some Cosy Classic builders?

Edited by Voidhawk9

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Hmm,  I would guess the tape on the left is usable but it does not look like it was woven so as allow removal of the crossthreads.  The tape on the right is more desirable because you can snip the tiny red thread and remove the crossthreads.  That gives you a tighter pack in the spar trough and straight fibers resist buckling better.    Hard to say (for me) if the left tape would make a big difference but these airplanes are slightly stronger than needed so maybe it doesn't matter.  

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I have bought some 3" uni tape from France, believed to have been intended for someone's canard project, but never used. It is a bit different to the 'usual' heavy stuff....

Can anyone advise on whether this tape is a good substitute? Perhaps this stuff has been used by some Cosy Classic builders?

You have some random material that you think might have been intended for an airplane but you don't know. It's not the same as the approved material. You don't know what it is, you don't know it's properties, you don't know whether they compare well to the material that's supposed to be used, you don't know if it's got a different finish, you don't know if it's ever been wet, and you want to know if you should use it for the single most important structural component of a device you're going to lift your family to 10K ft above the surface of the earth within. Could it work? Sure. And you could use hardware store bolts instead of AN bolts, and elmer's glue instead of epoxy. This is kind of that, unless you can determine what the properties of the material you've got a roll of are.

 

The total cost for the approved material (not counting shipping) at $1.85/yd for the 282 yds needed for the COZY MKIV, with a 50% margin for extra and losses, is $782.55.

 

I think you can discern what my recommendation would be.

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Right - that's why I'm hoping someone will recognize it and enlighten me as to its properties. Otherwise it will not be going into my aircraft.

It is in good condition, I removed it's original packaging myself, unfortunately no useful information was on it.

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Right - that's why I'm hoping someone will recognize it and enlighten me as to its properties. Otherwise it will not be going into my aircraft.

It is in good condition, I removed it's original packaging myself, unfortunately no useful information was on it.

There is no way to "recognize" it from an on-line pic, and the analysis required to determine what it actually is would cost more than just buying the right stuff... I'm glad that you won't use it unless you get proof of its acceptability.

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