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Re: "Carbon" Dragon? 10 Dec 2013 23:05 #562

My copy is marked copyright 2009 and has a photo of the Pioneer 3 on the cover.

--- In This email address is being protected from spambots. You need JavaScript enabled to view it., Rick Mullins wrote:
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> The copy I have that was published in 2008 only goes to page F-10. Do you have a newer version?
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> ________________________________
> From: Dewey <dew_or_di@...>
> To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> Sent: Friday, February 3, 2012 2:42 PM
> Subject: [Carbondragonbuildersandpilots] Re: "Carbon" Dragon?
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> Â
> According to page G-4 of Marske's Composite Design Manual it is one layer of 7725 cloth with spruce capstrips.
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> --- In This email address is being protected from spambots. You need JavaScript enabled to view it., Rick Mullins wrote:
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> > Marskes rib was constructed with a glass web that was laid up on corrugated steel he got off a tractor trailer. I'm not sure it's a single layer, I know a guy that helped him construct it, I'll check. But how would you know if it's the lightest/strongest unless you test a few different types? The point I was making is that because the Pioneer is heavier and faster than the Dragon, duplicating those techniques on the Dragon would probably result in it overbuilt and heavier than needed. I liked Yasushi's work and would probably duplicate it unless Philip's test prove he can make one lighter. There is a rib test in the files section that showed a foam rib with spruce cap strip the strongest of the types he tested, but I don't believe he tested a rib constructed the way Philip has.
> > f1.grp.yahoofs.com/v1/sC4sTyiR0ePpayaXn-...y7Ql7eWE/RibTest.pdf
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> >
> > ________________________________
> > From: Dewey <dew_or_di@>
> > To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> > Sent: Friday, February 3, 2012 1:34 PM
> > Subject: [Carbondragonbuildersandpilots] Re: "Carbon" Dragon?
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> >
> > ÂÂ
> > Are you saying that to use the construction methods of the Pioneer would be inappropriate? How can a rib be built lighter than with one layer of cloth? The same goes for the D-cell. If it strong enough for a heavier, faster plane would it not be more than strong enough for the Dragon's structure? A foam-cored rib with glass on both sides has to weigh more than this type of construction and what would cored construction in the rib or D-cell gain you? Yasushi's plane has plain foam ribs with ply capstrips and that seems to work well.
> > If I am missing something please let me know.
> >
> > --- In This email address is being protected from spambots. You need JavaScript enabled to view it., Rick Mullins wrote:
> > >
> > > The Pioneer has a different design mission. It has more of an emphasis on speed and glide and is built much heavier (345 lbs as compared to the Dragon about 150.) The Dragon is all about very low sink rate and low weight is much more important. While some of the construction techniques could be applicable, you are really comparing apples and oranges.
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> > > ________________________________
> > > From: Dewey <dew_or_di@>
> > > To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> > > Sent: Friday, February 3, 2012 11:34 AM
> > > Subject: [Carbondragonbuildersandpilots] Re: "Carbon" Dragon?
> > >
> > >
> > > ÂÂÂ
> > > Why all the experimentation with rib construction with cores? Jim Marske made the ribs for the Pioneer 3 from one laminate of7725 fabric with wood capstrips. This plane is a bit heavier than the Dragon and none has ever failed. The D-tube is also built without a core from three laminations of glass, again with no failures in a heavier, faster airplane. Why not use these proven techniques instead of getting wrapped up in one small aspect of design?
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> > > --- In This email address is being protected from spambots. You need JavaScript enabled to view it., Kenny Andersen wrote:
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> > > > Once again Russ -- you aren't making any sense.  If you are loading your core in compression, you are doing it wrong.  If the sandwich skin is failing, it's too thin...
> > > >
> > > > --- On Thu, 2/2/12, russell wilson <ruzty27@> wrote:
> > > >
> > > > From: russell wilson <ruzty27@>Subject: Re: [Carbondragonbuildersandpilots] "Carbon" Dragon?
> > > > To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> > > > Date: Thursday, February 2, 2012, 5:57 PM
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> > > > hi phill.......a heads up on the pannels you are making...8g/32kg......your comparing to a standard rib...yer?........my test pices/tested to distruction and compared on a balance beam......showed that any core material under 200kg was a loser with thin laminates....in a 200 kg core i had to go down to 2 oz glass before the skin failed under tension.....all other failures were of the compression skin buckling in toward the centre of the pannel/core material failing under compression.
> > > >  you may have a winner when compared to a standard rib...but there are lighter stronger options.....try some samples of the cheepest crapiest ply you can find....find a thikness that will match the weight of your expensive foam...lay it up with your cf and test it to destruction....you will find it will absorb less resin than 32kg so the finished pannel will be lighter and it will be stronger and cheeper/free core if you scrounge........then do one with bolsa(not end grain as end grain has tiny holes that go from one side to the other and the resin will fill these.)
> > > > my test showed that with thin laminates....do not use a core lighter than 200....even a thinner pannel of 200kg and above out performs thicker lighter cores with thin laminates....even though we know that dobling the thikness, much moor than dobles the
> > > > strenth /stifness. hey while your testing...i never got oround to testing woven jute fibers/hesian...these fibers are round the same strenth as e glass and lighter than kevlar and cheep as chips.
> > > >  russ.

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