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Re: plywood properties 12 Dec 2013 00:28 #710

what mask wing is refered to in relation to spar cap specs?im asking becaus i want to know if it is built in one pice or two?

a throw reserve is cheeper and lighter.no reserve needed for under 300 foot.ie low ridge soaring..not enough time to deploy or open.

what materials will you use?standard dragon?

what pilot body weight?

i will give feed back on pilot ,instruments,aircraft,reserve weights....for initial calculations.

russ





On Sat, Jul 30, 2011 at 3:34 AM, Kenny <This email address is being protected from spambots. You need JavaScript enabled to view it.> wrote:


that should have said the load in the spar cap, not longeron -- it's just past 2AM in Korea and I really need to get to bed! LOL



--- In This email address is being protected from spambots. You need JavaScript enabled to view it., "Kenny" wrote:
>
> I haven't plowed through the numbers yet. The force in the either cap of the longeron is basically M/h where M is the moment at whatever wing station is being checked and h is the height from the enter of the group of rods on the top to the center of the group of rods on the bottom. My buddies wing passed the static test and he used 200 Ksi for the rods in tension and 100 Ksi for the rods in compression (this is about 1/2 the published allowables); but, he also used the same number of rods in the upper and lower caps. That means that he basically used 100 KSI as the cut-off stress. Theoretically you could use a few less rods in the lower cap (since it's in tension). I think wood is about 15 KSI or something like that - I have to look it up, I don't really use any wood at work (though I'm not opposed to it for a home project, it doesn't really fit the kind of environments that I'm usually sizing for).
>
> He also said that rather than use the circular rods again like he did on his prototype, he would use the flat bar. There are too many voids that have to be filled with flox when using the round rod which adds a lot of weight. The rectangular flat rod has a better packing ratio with few voids and so will be lighter for the same area. It comes in .057 thick strips (this is the thickest it can be and still be rolled up for shipping and we need LONG pieces so you have to get them to give you a roll rather than strips) which is kind of an odd number, but it is what it is.
>
> The only thing I need to run down before I start calculating the number of rods is how the tapered wing is loaded. My buddy's wing is a constant section, so it is conservative to assume that the wing load is uniform across the length (in reality it's a bit lower at the ends); however, a tapered wing loads the inner part more where there is more area and it's really too conservative to assume constant loading. My Bruhn had a simple example, that I was going to review, but haven't got to yet (plus I don't know whether the generic tapered wing distribution will be the same as the CD -- probably not that far off).
>
> I'm off next week as it's company vacation time in Korea, and I was hoping to get started on the FE model, but I didn't get a print of the drawings (sill trying to find someone over here to do that), and my buddy that was supposed to get me access to the FE package is supposed to have left it to another guy to give to me before he left on vacation out-of-country and I have to fetch that (if he remembered to give it to him!). This is why every project takes years longer than you think it will!
>
> What I was going to use for weight (initial) calculations is:
> 155 airframe
> 25 ballistic chute (I'm guessing actual weight closer to 18 lb)
> 220 pilot and equipment.
>
> That is 400 fly-away -- anybody see a problem with that?
>
> Kenny
>
>
>
> --- In This email address is being protected from spambots. You need JavaScript enabled to view it., "Philip Lardner" wrote:
> >
> > Does anyone have a schedule for laying up the main spars using carbon rods for the spar caps and carbon cloth for the shear webs? How many rods (round or rectangular) - and their lengths per spar cap? Jim Marske describes the various calculations in his 'Composite Design Manual' but I'm not entirely comfortable with my knowledge of the subject. Kenny?
> >
> > Does anyone have the details of Steve Arndt's Magic Dragon wing spars?
> >
> > Phil.
> >
> > PS - my newly converted 29' long workshop is now re-roofed, re-floored, painted, insulated, electrified, lit, secured and ready for action! Tools are arriving from various corners of the earth... progress is imminent!
> >
> > PPS - I located a number of suppliers of 0.8mm plywood in the UK - all charging around £50/sheet of 4' x 4'. Expensive stuff! A little more research turned up a wood veneer supplier in Dublin (practically on my door step) who is offering 0.5mm veneers from €1.50 - €5/m-sq! ...and it comes in 4' x 8' sheets :-) With sufficient support along the long dimension, between the external rib forms, this stuff should be perfectly suitable for use as a female mold for the leading edges. At that price I could even use two layers to beef up the mold skin and still not break the bank!
> >
> > _____
> >
> > 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 Kenny
> > Sent: 29 July 2011 11:11
> > To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> > Subject: [Carbondragonbuildersandpilots] Re: plywood properties
> >
> >
> >
> >
> > The idea would be to sell multiple sets so that the cost can be spread out over several sets... Kind of like the wing tips somebody is selling! You have more experience at it, so you would know what would be reasonable.. it's just a bit 'inefficient' if everyone is repeatedly building tooling. The SD-1 uses a carbon spar -- I don't think their kit price seems too unreasonable -- buying the spar is mandatory since they use some tolling to produce it.
> >
> > --- In This email address is being protected from spambots. You need JavaScript enabled to view it. , "george_rf1" wrote:
> > >
> > >
> > > It would be REALLY good if there were someone willing to make the carbon spar and Leading edge â€" that's something I would pay to have done.
> > >
> > >
> > >
> > > That's very interesting , please do tell us, what would you expect to pay to hire someone to make the molds for leading edges and spars and the set of parts for you.
> > >
> > > George

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