Composite Spec'ing

[steveinindy]

Does anyone know a good introductory to intermediate-level source of information on how to choose particular composite materials (as in the specific brand and model of fabric, epoxy, etc) for specific applications?

[spungey]

AviationSpruce or Wicke's?

[steveinindy]

I am looking for stuff more technically oriented than what they have to offer or more so how to interpret things that are more technically oriented than what they have to offer since the decision is coming down not "Do I use Kevlar or E-Glass here?" but to "What grade/type/etc of carbon fiber do I want for this particular application?". I have a lot of the technical specs for things but I have little specific experience in these particular aspects (my area of knowledge is injury biomechanics, not materials science at this level).

[Mike Switzer]

Steve - take the Sportair composite workshop at IUPUI (or Versailles or whatever they are calling it now, on the north side of the big airport) next time they have it

I took it several years ago, it was taught by an engineer that worked for Rutan (cant remember his name off the top of my head) & Troy Grover from Danville / Avon helped out some, pretty good, I learned a lot & it convinced me I did NOT want to use fiberglass composite construction for the structure on my project...

My project will look a lot like a Long EZ but it will be tube & fabric......

[steveinindy]

Steve - take the Sportair composite workshop at IUPUI (or Versailles or whatever they are calling it now, on the north side of the big airport) next time they have it

Oh, the Vincennes University "campus" up here? LOL

I took it several years ago, it was taught by an engineer that worked for Rutan (cant remember his name off the top of my head) & Troy Grover from Danville / Avon helped out some

Ah....OK. I think I have met Troy before.

pretty good, I learned a lot & it convinced me I did NOT want to use fiberglass composite construction for the structure on my project...

Why is that? Granted, I want to stay away from the standard foam core composite technique that a lot of homebuilders use since it's not the best thing for occupant protection but I would be interested in hearing your reasoning for choosing a more traditional method of construction.

My project will look a lot like a Long EZ but it will be tube & fabric...

Very interesting. Mine will look like a traditional aircraft. After a conversation with Rutan, I decided to ditch the idea of a pusher configuration although I might come back to it in a later design just for the challenges involved.

[Mike Switzer]

Why is that? Granted, I want to stay away from the standard foam core composite technique that a lot of homebuilders use since it's not the best thing for occupant protection but I would be interested in hearing your reasoning for choosing a more traditional method of construction.

While i wanted to be a design engineer for Ford, I couldn't because 1) my grades weren't real great & 2)the year I graduated they laid off 6000 engineers

So I went to work for ADM, got lots of training as a maintenance engineer & went on to do that as a consultant for a lot of similar companies.

Foam core composite is easy to build in your garage, but it is a real pain to ever fix in the future. It is also pretty much impossible to determine if it was constructed properly without doing destructive tests.

With Tube & fabric, I can design all the structural elements, then add all the controls BEFORE I cover it, makes it real easy to work on, plus the guy that taught the composite class told me tube & fabric was the lightest construction method out there.

And if it ever gets screwed up. get out the carpenter's knife, cut off the fabric, fix it & re-cover it.


Edit - plus I'm scared of fire & I know what a foam core does when it gets hot....

[David J. Gall]

steveinindy, in answer to your question about composite spec'ing: I found Jim Marske's excellent but terse Composite Design Manual (http://marskeaircraft.com/) to be very helpful, and Andy Marshall's book which is available from EAA and all the usual sources. You can also try Martin Hollmann's books, but they're kind of simplistic for my tastes, although they cover things like fabric weaves and core materials fairly well, as well as manufacturing methods (vacuum bagging, etc.). Marske touches on that, too, as well as fitting design and tooling and joggles. I have more "Engineer-y" references if you want them. Try searching the web for Mil HDBK-17, NASA CR-4750, NASA RP-1351, and the General Plastics and Hexcel websites (and others) for core material product data sheets. You might also like the Structural Analysis Reference Library website: http://euler9.tripod.com/.

[corsair82pilot]

Here is a link to the "Reference" section of my website. I did a lot of composite research and testing while developing my composite Corsair.


http://corsair82.com/corsair/reference/reference.html

Most of these books are in the EAA Book Store. Some can be found on Amazon.