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Re: plywood properties 12 Dec 2013 00:26 #709

sorry Russell, you've jumped the shark -- I have nearly no idea what you are talking about. The CD has a 'closed' cockpit -- you gonna throw that chute out after you roll the window down? seems simpler to have a ballistic shoot similar to Steve's. You may not get the full effectivity, but you may get a little slow-down. I could certainly pull a handle WAY faster than I could get rid of the canopy and throw a chute out, but that's just my thinking. If it were an open cockpit, then I think what you are saying has some merit -- am I missing something? Everyone knows there is a dead-man zone -- EVERY aircraft has one (some larger than others).

--- In This email address is being protected from spambots. You need JavaScript enabled to view it., russell wilson wrote:
>
> 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 <kennyrayandersen@...> 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"
> > <kennyrayandersen@> 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"
> > <philiplardner@> 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. [mailto:
> > 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. > > Carbondragonbuildersandpilots%40yahoogroups.com> , "george_rf1"
> > <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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