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brainfart

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  • Plane Type
    Other (Non-canard)

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  1. How will you test it? Trying to tear out the anchoring points?
  2. Nice. But I really worry about post-curing with balsa in there. 200 degrees Farenheit (110°C ?) is quite a lot. The Tg of MGS is somewhere up there, and you don't need to raise the post-curing themperature to or even above the glass transition temperature. Heating to 20°C (40F) below ultimate Tg for 5-8 hours or so is sufficient, there's no need to heat it up that much. Are you going to try this out on one of the smaller molds first? I'd hate to see the bigger ones ruined since the balsa started to outgas or something.
  3. If you redo it anyway then why don't you try removing the glass, or practise doing repairs on that part. Don't throw it away.
  4. Is there any other aircraft/canard related stuff out there that copyright-infringing evildoers might consider worth downloading?
  5. *** Bump *** http://www.reaa.ru/cgi-bin/yabb/YaBB.pl?num=1189771013/870
  6. From my experience (lots of glass and visible carbon surfaces) it is best to work the epoxy through the fabric from the bottom with a DRY brush or squeegee if you want bubble and pinhole-free layups. When resin is poured on glass it gets impermeable for air and the bubbles are trapped in the layup. If you let the resins oak through the fabric from below the air can get out and there will be much less bubbles and pinholes.
  7. > Correct me if I'm wrong, but in Europe... Europe is a big place. In some coutries you might not, in others you can.
  8. > down side is that my girlfriend got to see a couple of Cozy IV and Long EZ up > close and want me to buy/build a Cozy IV Get that in writing, put it in a frame in your shop and then marry her!
  9. > it is also hard to know if the fuel has alcohol in it. the pump gas may or may not. > it only says it may contain alcohol. how do you know that the sample you have does? If in doubt, add some alcohol intentionally.
  10. Got any links so we don't have to read through countless pages of info?
  11. > How about some tests. Can't hurt to do them, but what's the benefit of a limited sample made under possibly questionable circumstances tested with non-adequate equipment... There are thousands of laminated aircraft flying. These tests have been done countless times before under controlled conditions by experts. Just do it the way the experts and commercial aircraft builders do it. Even if some of the information might collide with 30 year old videos or outdated books written in the seventies.
  12. Been playing around with the Arduino a few years ago, as a way to start learning about microcontrollers. I've heard about the arduino autopilot but haven't checked out the details yet so I can't really comment. Might be a nice addition that is easily upgradeable, but then again it might not. Just reminding that a bunch of accelerometers do not substitute for real gyros.
  13. INTRODUCTION TO COMPOSITE MATERIALS http://ocw.mit.edu/NR/rdonlyres/Materials-Science-and-Engineering/3-11Mechanics-of-MaterialsFall1999/5991E176-AC60-4399-87F0-86AE35963750/0/composites.pdf I guess that's why countless texts like the above mention stuff like "fiber volume fraction" and "matrix volume fraction" all the time, in a subtle kind of way... All I'll tell you is what the industry and academia uses and expects, and how it gets measured, at least outside the USA.
  14. > Volume fractions are used when mixing the two (or more) EPOXY components. Sometimes, by some people... > Mass fractions are used when determining fiber/mixed epoxy ratios. I guess we disagree on the volume fraction stuff then. Strange world, there are quite some differences between the two sides of the pond. Americans measure fuel consumption in miles per gallon, we use liters per 100km. Most epoxies are weighted here, rarely mixed by volume. And for fiber content comparisons of laminates we use volume fractions. > Again - how would one determine the volume of woven cloth? Density of the raw material is known. Yarn diameter is known. Weight per lenght is known (1 tex = 1g/km), grammage (weight per area) is known. Thickness of the cloth and the laminate is known. More than enough data to come up with a volume ratio, don't you think?
  15. In all (mostly non-English) language publications I have seen so far, volume fractions are being used. Yes, many people indeed confuse mass and volume fractions.
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