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Re: Wing ribs 09 Dec 2013 01:11 #420

I am not able to proto-type where I am, but have been following this thread closely and with great interest. My concerns in order are strength, build time, and cost. I think my idea of cnc routing out a CF foam CF sandwich has loosed out to the female mould design. The sandwich just would not have the strength to weight, but boy would it save time! In the interest of expense and time to build I was thinking about making a female mould optmized for bi-directional tape laid in the U chanel with an added uni tape on on the caps. I hope that by using the tape a minimal amount of trimming will be needed once the resin has cured. This also appeals to me as I want to avoid the health costs of grinding carbon. -Ed



From: KarlS <This email address is being protected from spambots. You need JavaScript enabled to view it.>
To: This email address is being protected from spambots. You need JavaScript enabled to view it.
Sent: Tuesday, March 6, 2012 3:09 AM
Subject: [Carbondragonbuildersandpilots] Re: Wing ribs




Phil that is an excellent idea to sandwich the rod between cloth layers and eliminate the wood.

Should molds ever be made for CDII it was my thoughts also to run continuous rods from nose to tail sandwiched between cloth to prevent compression failure.

Kenny would this constitute covering the rod sufficiently? This would more or less be similar to what I did on my landing gear layups.

Phil could you replace the wood in the pod with rod? That is really making it more of a Carbon Dragon for sure. Both sides of the fuse are more or less triangulated wood structures. I think the rod would be perfect to replace the wood. It sure would bend for some nice lines but.. taking the rod out of linear lines defeats the strength advantages. Maybe the triangulation of the structure would gain the strength back. Kenny your thoughts??

I have to ask if anyone could generate sectional drawings of the Axel from the 3 view we have. I am about ready to start a plug just because. Mainly to test the graphlite rod in a carbon layup sandwich. I could build plugs from the 3 views but sectional slices would save a lot of guessing. I would like to use the Axel as a starting point.

Any opinions on a composite fuselage as opposed to a simple truss type build? I personally am tossing around both ideas.

Somewhere I read Jim Maupin and Irv Culver wanted the Carbon Dragon to be a base for future development. It is weird that the internet was not there when they designed it to allow something like that to happen but what a great tool it has become.

One more thing.. the comment about the "lifting body" and "skunk works".. I have to ask if the CD was in some way derived from this technology? Just curious.

Karl

--- In This email address is being protected from spambots. You need JavaScript enabled to view it., "Philip Lardner" wrote:
>
> Yes, I was pleasantly surprised by the cost of the rod for the wing spars
> and ordered enough to do the elevator spars, tail, rudder and tail boom also
> (more experements needed, but I want to eliminate the wood-carbon-wood
> sandwich longerons in there too!)
>
> In the tail boom I reckon that if you bonded carbon rods (in place of the
> wood/carbon longerons) to the outer CF skin and enclosed them under another
> layer of CF cloth you would probably end up with a plenty strong enough
> boom, and a much lighter one. I also plan to replace the mahogony ply
> internal rings/supports with CF/5mm-foam/CF sandwich cutouts - again, much
> lighter and plenty strong enough.
>
> I'm still pondering various ideas about how to go about making the pilot pod
> - I reckon there's lots of weight to be lost there.
>
> Phil.
>
> _____
>
> From: This email address is being protected from spambots. You need JavaScript enabled to view it.
> [This email address is being protected from spambots. You need JavaScript enabled to view it.] On Behalf Of KarlS
> Sent: 06 March 2012 01:15
> To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> Subject: [Carbondragonbuildersandpilots] Re: Wing ribs
>
>
>
>
> The rod is actually fairly reasonable on costs. I believe the rod if
> properly engineered would not cost that much for say a fuselage. Making box
> beams or triangular beams with foam core and then triangulating them into
> structures wouldn't be that expensive.
>
> A fuselage nose shell with nice shape and a triangulated tail or box truss
> structure covered with dacron would look great. Super light weight and
> simple.
>
> You can always sell the house. :-) Just my 2 cents.
>
> Karl
>
> --- In This email address is being protected from spambots. You need JavaScript enabled to view it.
> <mailto:Carbondragonbuildersandpilots%40yahoogroups.com> , "Philip Lardner"
> <philiplardner@> wrote:
> >
> > I investigated pultruded carbon tubing also and even purchased a sample:
> >
> >
> www.easycomposites.co.uk/products/carbon...ction/carbon-fibre-b
> > ox-section-8mm-7mm.aspx
> >
> > This stuff is incredibly light and would be ideal for the straight
> sections
> > of the ribs and particularly or making up the flaperon ribs. There are two
> > down-sides to this stuff: at 0.5mm wall thickness it is rather easy to
> > crush, and the other problem is... the price! I calculated the number of
> > meters of this stuff I'd need and then hid behind the sofa when I worked
> out
> > the price! It *is* a beautiful product, though, and very light weight.
> >
> > Phil.
> >
> > _____
> >
> > From: This email address is being protected from spambots. You need JavaScript enabled to view it.
> <mailto:Carbondragonbuildersandpilots%40yahoogroups.com>
> > [This email address is being protected from spambots. You need JavaScript enabled to view it.
> <mailto:Carbondragonbuildersandpilots%40yahoogroups.com> ] On Behalf Of
> Kenny
> > Andersen
> > Sent: 06 March 2012 00:05
> > To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> <mailto:Carbondragonbuildersandpilots%40yahoogroups.com>
> > Subject: Re: [Carbondragonbuildersandpilots] Re: Wing ribs
> >
> >
> >
> >
> >
> > Karl,
> >
> > I wasn't referring to the rod, but to the tubing. The rod bends quite
> > easily, but the tubing does not. I'm thinking something along the lines of
> > the basic wooden rib only mad from hollow composite. In this application
> > (as opposed to the wing spar) there would be a minimum length to get all
> of
> > the load sheared into the rod. I'm thinking MAYBE the uni tape might be
> > more apropos on the rib caps?
> >
> > --- On Mon, 3/5/12, KarlS <kschneider@> wrote:
> >
> >
> >
> > From: KarlS <kschneider@>
> > Subject: [Carbondragonbuildersandpilots] Re: Wing ribs
> > To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> <mailto:Carbondragonbuildersandpilots%40yahoogroups.com>
> > Date: Monday, March 5, 2012, 5:59 PM
> >
> >
> >
> >
> > Kenny,
> > We have been using this .125 rod for model aircraft spars. The .125 rod in
> > the 12 foot lengths come shipped in about a 2 foot diameter roll. It bends
> > easily and would go around the curature of the wing rib without a problem.
> >
> > www.aircraftspruce.com/catalog/mepages/graphliterod.php
> >
> > Jim Marske also sold a variety of square rod that may work better. I'm not
> > sure if he still sells it or not.
> >
> > Rick Mullen might be able to answer that.
> >
> > Karl
> >
> > --- In This email address is being protected from spambots. You need JavaScript enabled to view it.
> <mailto:Carbondragonbuildersandpilots%40yahoogroups.com> , Kenny Andersen
> > <kennyrayandersen@> wrote:
> > >
> > > I've given this some thought and think it MIGHT be possible; BUT, you'd
> > have to make your own rods due to the curvature issues that Phil pointed
> > out. Â Also, most rods are actually TOO robust for what we are doing. Â I
> > was thinking more like square Carbon tubes so that you still had
> > significant area to bond to, and I completely agree with Phil -- you'd
> want
> > some type of gusset at the joints. However, if you used square tube, I
> think
> > you could bond them all rather than use a mechanical attachment. Â Where
> > there is a will there is a way. Â I was thinking you could make the tubes,
> > as a minimum, out of unidirectional tape wrapped in the 2 oz glass. Â
> Maybe
> > 3/4 X 3/4 test that and see what it got you...
> > > You likely have to make the curved ones over foam, then eat the foam out
> > with something... Â Just a thought.

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