Ed I really like your ideas.

I don't want to keep beating the Graphlite rod thing but..

Along the lines of what you have described fits into a concept I have had also.

The graphlite rods have an enormous amount of strength that really puts them into a class all by themselves. We have captured some of the what I like to call energy in the new spar systems.

Jim Marske's Genesis wing ultimately failed in a comercial test rig condition at somewhere up around 18g's.

The point is it takes a very small amount of this product to do the work of alot more of old product.

The thing that has to be done is capture the energy.

The highest strength properties are when the rods is in linear lines.

It is my thoughts to use angle steel or aluminum as a mold to build the truss graphlite rod frame. Like you said Ed to apply a release mechanism to the metal so the part will release after the resin has cured.

It is critical to maintain the linearity of the rod if configured as a truss assemble.

Imagine one leg of the truss being made from one piece of say 2 inch aluminum 90 degree angle as the mold. For sake of clarity this would be the outside corner of the tail truss if in a box configuration.

Apply layers of bidirectional cloth to the inside of the angle metal.
Place the graplite in the corner of the angle on the inside. This is how Jim Marske builds his spars basically.

Place 2 more rods on the outer part of the angle. Take the cloth that was applied initially and wrap it around the outside rods and back to the corner rod.

What you end up making is carbon angle with graphlite rod on the corners. The 2 outside rods are there just to stabilize the corner rod and maintain linearity. You could also use blue foam cut as a triangle and place it in this assembly and then a second layer for cloth vacuum bagged around the whole assembly.

Here's a link to a sketch.

groups.yahoo.com/group/Carbondragonbuild...inal&start=1&dir=asc

Most things fail due to compression failure as in carbon tubes. Use the graphlite rod properties to defeat the weak point.

Just as Rick Mullins said (I think it was him) or maybe Phil about capturing graphlite rod in their tail boom and eliminating the wood longerons.

I need to build one to prove my points. I need to finish my current project. There are a lot of people waiting.

Sorry for the book again.

I have to mention I learned a lot from a good friend on some of this.
We were co designing a plane a few years ago. He is the head of a physics dept at a major university and a brilliant man.

Regards,

Karl

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

> I spent a lot on time considering how I would join the truss members. This is what I came up with.Â
> Imagine the fuselage already tack glued together at each joint. Now we need to add gussets for strength at the point of intersection of the tubes. For this example we will consider a simple case where a horizontal tube meets perpendicular to a longeron and then a perpendicular vertical tube descends from the longeron. This is what we will gusset
> Take to metal plates (.032 or so) and cover them with shrink/heat shrink wrap for a mould release as marske suggests. Butt these two plats against each other.
> Cut out your gusset from CF cloth. Wet it onto the metal plates with the center of the gusset where the 2 plates meet.
> Take the plates and lay the CF face onto the tube. Then clamp the plate to the tube with 2 clamps on the longeron and one on the horizontal.
> Next naturally lay the fabric onto the longeron as you rotate the second plate onto the vertical. Clamp as before.
> From the inside lay tape across the tubes onto the gusset to capture the structure from both sides.
> Â
> The clamps I would use have an offset to allow the tapes underneath to be applies while the gusset is still wet. I would design them to grab the tube in one area from both sides and then have a spring loaded arm to hold the gusset tight against the surface.Â
> Â
> Well, that's it for tonight. Thoughts? -Ed
>
>
> ________________________________
> From: Kenny Andersen <kennyrayandersen@...>
> To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> Sent: Wednesday, March 14, 2012 11:20 AM
> Subject: Re: [Carbondragonbuildersandpilots] Re: CDII -fuselage
>
> Â
> Ed,
> I prefer my stress with tears thank you! Unless you get into a situation with a lot of changing contour, the difference in fiber direction should not be too much. I remember some investigations into the intake of the F-22 (which is highly contoured) and some of the fibers were 22 deg off what was being used in the calculation due to the contour.  If you are just wrapping a cylinder -- no worries.  I'm not sure why they'd want the plies at 45 degrees though.  The buckling will be lower because the modulus in that direction is lower.  I was thinking maybe to use some unidirectional tape wrapped with some of that really skimpy glass to protect it.  I'd have to do a little investigating to see which was lighter/stronger in the end...  Stuffing the foam inside the tube (with the adhesive, or what's the point) will NOT be easy -- why not just wrap the plies around the foam core?
>
> The big challenge thee is of course joining all of the truss members and making them to contour -- not impossible, but challenging
>
> One think to remember is that the biggest loads the fuselage will see are 1) handling loads) 2) landing loads. Â If you can clear those to, the flying is a cake-walk.
>
>
> --- On Wed, 3/14/12, Edward Pickens <pt6jumperdriver@...>wrote:
>
> >From: Edward Pickens <pt6jumperdriver@...>
> >Subject: Re: [Carbondragonbuildersandpilots] Re: CDII -fuselage
> >To: "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.>
> >Date: Wednesday, March 14, 2012, 2:39 AM
> >
> >
> >Â
> >karl,
> >Â
> >I used some basic truss calculations and some asumptions for the loads that will be placed on the frame by the empenage. There is a great book "Stress without the Tears" that will walk you through the calculations. It is a must have for your aviation library. I just made a bunch of oversimplified assumptions for the structural design and modeled the fuselage frame after your basic steel tube glider. One question that I have yet to answer is the buckeling strength of the CF tubes. You can try to do some Euler calculations, en.wikipedia.org/wiki/Buckling, or look at charts for similar materials, but without testing a few sample to destruction, you just don't know. Â
> >Â
> >My plan is to make a CF tube with CF sleves such as from this website. www.acpsales.com/OnlineStore.php?cat=4957. They appear to be 5.6 OZ cloth with the fibers in a 45 degree orientations.  One concern with making your own tubes is that the fibers may not be a true 45 to the axis. This will reduce the strength a little. The required strength will determing the number of sleeves per tube. I am planning on covering either a steel or PVC pipe with shrink wrap and moulding the sleeves on the outside. Very similar process to what Marske suggests. If I need to bend a tube for what ever reason, I think you can encase it between 2 pvc halves, run warm air inside to get it over its transition temperature, and then bend it as required. To increase the buckeling strength I plan to cut out foam cylinders and stuff them inside the tube at a yet to be determined spacing.
> >Â
> >I am currently traveling and do not have most of my calculations with me. If I did I would have posted a spread sheet that I could stand by. From the basic calculations that I performed I can definatly say that it is worthy of more study.  After that other email that I sent I started to redesign a basic fuselage on autodesk inventor. I wanted to make it similar to the monarch from the spar forward and a tube frame for the rear. I feel that the monarch fuselage may provide better crash/hard landing protection to the pilot. I also like the simplicity of an open cockpit design.  I tried to design it on Autodesk inventor, but the designed lacked elegance, so I am back to the drawing board. I can say for certail that the CG calculation showed that there will be issues with a far forward CG. This is why i really want to know how much forward sweep I can get away with. What need now is a few pitures of naked steel tube
> sailplanes to get better ideas for the construction. I think a schleicher K 8 would be a god place to start. -Ed
> >
> >________________________________
> >From: KarlS <kschneider@...>
> >To: This email address is being protected from spambots. You need JavaScript enabled to view it.
> >Sent: Tuesday, March 13, 2012 11:28 PM
> >Subject: [Carbondragonbuildersandpilots] Re: CDII -fuselage
> >
> >Â
> >Hi Ed,It was I that suggested the carbon frame covered in dacron. That could be "hyper light". I was wondering about your calculations. Could you share any info? Just curious.I still believe it would be fairly simple for anyone to make carbon beams using graphlite rod and dow blue foam with a glass or carbon skin perhaps that converge into a carbon tube truss tail structure. Kenny and Dan had some dialog that was very similar to what I was thinking with a keel and side beams. I had drawn up some sketches months ago but they aren't that great and I was kind of embarrassed to post a picture. But exactly what Dan and Kenny discussed. To all,An option also for some of the construction to make it simple for the every day man is old fashioned aluminum. Very thin though. Not for the fuselage but maybe D tubes similar to the video below. Perhaps integrate some graphlite rod in conjunction with.That would be a lot easier than composite molds and layups etc.This
> is a great video. The dialog at the end is cute.

tossing ideas out there.Karl--- In This email address is being protected from spambots. You need JavaScript enabled to view it., Edward Pickens wrote:>> The comment about this being an important brainstorming session was spot on. I know I have learned a lot and considered solutions that I may never have reached if I was going about this by myself. The other day it was mentioned to use carbon tube covered with dacron to make the fuselage. I did some basic calculations, and the weight savings are increadible. It also dropped the cost a very substantial amount for the fuselage. The issue now is the CG is too far forward for big guys even with a little forward sweep in the wings. I was wondering if anyone knew of a book that covers forward sweep in detail. Every text that I own only mentions a few lines about forward sweep, then moves
> on. I would really like to know what my limits are and how the structure needs to be changed to accomidate the new wing design. -Ed