so what did your numbers say kenny.. 0.8mm ply D skin or lighter/thinner 0.3mm carbon D skin?
how much lighter is your standard size wing... 0.3mm carbon D skined ?

how much lighter/hevier is your scaled up size wing...0.3mm carbon D skined ?

if they are lighter...did this off set your extra body weight and give you your desired wing loading as you had planed?

is your wing as strong and as stiff in torshion as the standard wing?

is your wing stronger and stiffer in torshion than a standard wing as you had planed ,in order to compensate for your extra weight?

russ


On Thu, Jun 30, 2011 at 4:46 PM, Kenny <This email address is being protected from spambots. You need JavaScript enabled to view it.> wrote:


here is a link to some plywood information. AS I was saying, it's better if you can get the plywood at 45 degrees (2 of the 3 plies anyway) for spar webs and leading edges, but it does cost more. Of course, I guess you could make your own. This could be one thing you could do to increase strength even without going to a composite and I guess there would be nothing stopping you from making your own 45 degree plywood by cutting the regular ply at 45 degrees and splicing them together (bit of a hassle, but id you got more time than money...

www.recreationalflying.net/tutorials/scr...builder/plywood.html



--- In This email address is being protected from spambots. You need JavaScript enabled to view it., russell wilson wrote:
>

> hi keeny
> iv got some ply here that was suposedly left over from the wing skins/d
> tube...couldent find my vernias...mesured with a ruler it looks like 0.8mm
>
> russ.
>

> On Thu, Jun 30, 2011 at 11:52 AM, Kenny <kennyrayandersen@...> wrote:
>
> > **
> >
> >
> > I can run the numbers, but I need to know the thinckness of the ply
> > wood and the stiffness if anybody has it. I have data for the composites
> >
> > Generally, for the same material stiffness the buckling allowable goes up
> > as a function squared, the in-plane shear stiffness is only linear -- I
> > think you might be confusing area?
> >
> > Keep in mind that the stiffness of the carbon is MUCH higher than the wood
> > as well, so you really have to run the numbers. It might also be that in
> > common thicknesses, plus the curved shape, the plywood may be thicker than
> > required. In addition to that, with the graphite fabric, you can tailor the
> > lay-up to get the stiffness in the direction you want (i.e. more plies in
> > the +- 45 degree direction, which helps with the shear buckling (D tube
> > should react the torsion).
> >
> > The density is around .06 Lb/in cu vs .1 for aluminum