Large Diameter Extrusion

Soar_dude · Nov 04, 2009, 09:48 PM

Hey All

Does anyone know who makes 3/4" diameter carbon fiber extrusions for wing joiners?

Soar Dude

vintagesailplnr · Nov 05, 2009, 12:41 PM

Soar Dude:
CST may have what you need. I know (used to) that they have CF 1/2" rods and 5/8" tubes.

I've seen CF rod break - from a smimple slight scorring from the retainer tubes.

3/4" 7075 aluminium would be a good choice. Especially if it is $2.5K+ ship
Just some thoughts.......
Jim
PS: I've not seen or been told that my 1/2" 7075 Al ever took a permanent bend. I would think 3/4" would take any winch or two man tow! 1/2" titanium would be about as expensive as and better than 3/4" carbon, if you can find the CF - Speedy Metals for Ti.

Quote:

Originally Posted by Soar_dude

Hey All

Does anyone know who makes 3/4" diameter carbon fiber extrusions for wing joiners?

Soar Dude

Soar_dude · Nov 05, 2009, 03:08 PM

Yeah I have aluminum right now but I wood like to shed a little weight I am not to worried about any scoring as it goos into a composite joiner box so no metal contact. I think I found what I am looking for here http://www.acpsales.com/home.php?cat=4662.
I hope some of the guys on here might have some better ideas or a better product.
Soar Dude

ThermalBuster · Nov 05, 2009, 03:40 PM

Hard to believe that anything flying with a 3/4" wing rod is going to benefit much by the weight savings going from aluminum to carbon fibre. Also keep in mind that carbon fiber is "stronger than steel" by weight not by volume. You may need to increase the diameter to equal the strength.

Just some thoughts. Have fun whatever you do.

Rick

Soar_dude · Nov 05, 2009, 04:22 PM

I have and aluminum joiner right now I want something stronger and lighter which carbon is lighter and stronger then aluminum.

lincoln · Nov 05, 2009, 06:24 PM

Yes, but due to the sensitivity of carbon to notches, and due to the nasty failure mode, I don't think you can count on the carbon being "stronger".

An aluminum tube can be lighter than a solid carbon rod. If I'm not mistaken, the crossover occurs when the ID is around 3/4 of the OD. It might be a good idea to have something inside to prevent buckling right where the joint between wings is, but this wouldn't have to extend very far.

Also, aluminum isn't just aluminum. Alloy and temper matter. Unfortunately, I don't know which combination is the strongest that will still bend instead of breaking.

BTW, some carbon is stronger than some steel. Yield strength on steel goes anywhere from 30kpsi for the cheap stuff to over 200kpsi for music wire of a quarter inch or less, to much higher numbers for exotic stuff that I don't know much about.

Fiberglass is also very strong. I was thinking of using a fiberglass driveway marker for an odd task the other day, so I tested it for strength. Someplace above 70kpsi, I gave up. It's strong, but not stiff. A .330" diameter pole bent something like 30 or 40 degrees in 3 feet with a cantilevered load of 8 lbs. (Which, if I didn't mess up, gives a stress over 70kpsi, even when you subtract a few inches because of the bend.) I was flinching too much, so I gave up then. The stuff is floppy, but quite strong. At least in its unidirectional form. I've heard considerably higher numbers for unidirectional carbon, but not if you poke it (or the driveway marker) in the side with something sharp like the end of an unflared brass tube.

Soar_dude · Nov 05, 2009, 08:48 PM

I know about aluminum I was a airframes mech in the Navy for 20 years. The carbon fiber rod will be lighter and stronger then the aluminum rod I have now. The carbon will have more of a margin before it fails then the aluminum rod will so it will have "some" tolerance for defects in the Carbon fiber before it bending strength fails compared to the deforming of the aluminum rod as it fails but it will fail at a lower PSI then the carbon fiber. I am trying to cut down on the weight of a 2.5 meter hollow molded TD glider. There is no crossover of weight to size of aluminum and carbon fiber. As far as those driveway reflector stakes they work well as joiners for two meters. I built a two meter foamie for a friend of mine and it stands up well on my winch. I also use them for Spirit-o-76 2 peice wing.

peteapilot · Nov 05, 2009, 10:44 PM

I have been working with a wooden joiner wrapped with cf. sock 2 layers.You can sand down or build up to get the fit you want.Cabenit grade clear hickory or ash is the best ,and any shape will work if you take time to fit it. Suck it down with heat shrink tubing for the lay up

Soar_dude · Nov 05, 2009, 11:28 PM

Oh I like that idea about using a sock and heat shrink! Now I need to check if they make them in fiberglass or kevlar to act as abrassion barrier for the Carbon fiber.

vintagesailplnr · Nov 06, 2009, 08:51 AM

Hey:
Maybe I miss-understood..... I thought sanding carbon fiber(s) ruins its strength?
Jim

Quote:

Originally Posted by peteapilot

I have been working with a wooden joiner wrapped with cf. sock 2 layers.You can sand down or build up to get the fit you want.Cabenit grade clear hickory or ash is the best ,and any shape will work if you take time to fit it. Suck it down with heat shrink tubing for the lay up

mlachow · Nov 06, 2009, 11:40 AM

If you are using solid aluminum rod, then go with a tube, or steel tube. Not sure how much weight you are trying to save and why.

When you get to larger sizes, then hollow tubes will be best for weight savings. For the most part, the inside of the rod is just going along as excess baggage.

peteapilot · Nov 06, 2009, 08:33 PM

Quote:

Originally Posted by vintagesailplnr

Hey:
Maybe I miss-understood..... I thought sanding carbon fiber(s) ruins its strength?
Jim

If your working for NASA that might be true

prodjx · Nov 07, 2009, 02:03 AM

I'm not so sure carbon can be extruded, does anyone know for sure?

Soar_dude · Nov 07, 2009, 10:42 AM

Carbon fiber extrusions are made by pulling resin impregnated tow thru a form then removed once it cures. I am sure someone on here knows the exact process.

schrederman · Nov 07, 2009, 11:46 PM

Back when I owned an interconnect business, one of my customers made composite extrusions. The rovings passed through a mold that was about 2' long. The resin was forced in at the beginning and the extrusion came very slowly, fully cured, out the other end. They were pumping some form of lubricating agent in at about the halfway point in the mold. The mold was heated and it stands to reason that they were using a special resin formulated for this application. The coolest part was the tape wrap that was formed around the rovings by rollers as it all passed into the mold. What I saw was an 8" I-beam being formed. It moved at about 2" per minute. They made buildings for highly corrosive atmospheres. There was about 15' of the beam sticking out of the finished end of the mold when I saw it.

Nov 04, 2009, 09:48 PM	#1
Soar_dude SSP#14 aspirant Join Date: Feb 2002 Location: Fort Lewis, Washington, United States Posts: 1,214	Large Diameter Extrusion Hey All Does anyone know who makes 3/4" diameter carbon fiber extrusions for wing joiners? Soar Dude

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Nov 05, 2009, 03:08 PM	#3
Soar_dude SSP#14 aspirant Join Date: Feb 2002 Location: Fort Lewis, Washington, United States Posts: 1,214	Yeah I have aluminum right now but I wood like to shed a little weight I am not to worried about any scoring as it goos into a composite joiner box so no metal contact. I think I found what I am looking for here http://www.acpsales.com/home.php?cat=4662. I hope some of the guys on here might have some better ideas or a better product. Soar Dude

Nov 05, 2009, 03:40 PM	#4
ThermalBuster Registered User Join Date: Sep 2004 Location: Orlando Posts: 270	Hard to believe that anything flying with a 3/4" wing rod is going to benefit much by the weight savings going from aluminum to carbon fibre. Also keep in mind that carbon fiber is "stronger than steel" by weight not by volume. You may need to increase the diameter to equal the strength. Just some thoughts. Have fun whatever you do. Rick

Nov 05, 2009, 04:22 PM	#5
Soar_dude SSP#14 aspirant Join Date: Feb 2002 Location: Fort Lewis, Washington, United States Posts: 1,214	I have and aluminum joiner right now I want something stronger and lighter which carbon is lighter and stronger then aluminum.

Nov 05, 2009, 06:24 PM	#6
lincoln Registered User Join Date: Dec 2001 Posts: 2,597	Yes, but due to the sensitivity of carbon to notches, and due to the nasty failure mode, I don't think you can count on the carbon being "stronger". An aluminum tube can be lighter than a solid carbon rod. If I'm not mistaken, the crossover occurs when the ID is around 3/4 of the OD. It might be a good idea to have something inside to prevent buckling right where the joint between wings is, but this wouldn't have to extend very far. Also, aluminum isn't just aluminum. Alloy and temper matter. Unfortunately, I don't know which combination is the strongest that will still bend instead of breaking. BTW, some carbon is stronger than some steel. Yield strength on steel goes anywhere from 30kpsi for the cheap stuff to over 200kpsi for music wire of a quarter inch or less, to much higher numbers for exotic stuff that I don't know much about. Fiberglass is also very strong. I was thinking of using a fiberglass driveway marker for an odd task the other day, so I tested it for strength. Someplace above 70kpsi, I gave up. It's strong, but not stiff. A .330" diameter pole bent something like 30 or 40 degrees in 3 feet with a cantilevered load of 8 lbs. (Which, if I didn't mess up, gives a stress over 70kpsi, even when you subtract a few inches because of the bend.) I was flinching too much, so I gave up then. The stuff is floppy, but quite strong. At least in its unidirectional form. I've heard considerably higher numbers for unidirectional carbon, but not if you poke it (or the driveway marker) in the side with something sharp like the end of an unflared brass tube.

Nov 05, 2009, 08:48 PM	#7
Soar_dude SSP#14 aspirant Join Date: Feb 2002 Location: Fort Lewis, Washington, United States Posts: 1,214	I know about aluminum I was a airframes mech in the Navy for 20 years. The carbon fiber rod will be lighter and stronger then the aluminum rod I have now. The carbon will have more of a margin before it fails then the aluminum rod will so it will have "some" tolerance for defects in the Carbon fiber before it bending strength fails compared to the deforming of the aluminum rod as it fails but it will fail at a lower PSI then the carbon fiber. I am trying to cut down on the weight of a 2.5 meter hollow molded TD glider. There is no crossover of weight to size of aluminum and carbon fiber. As far as those driveway reflector stakes they work well as joiners for two meters. I built a two meter foamie for a friend of mine and it stands up well on my winch. I also use them for Spirit-o-76 2 peice wing.

Nov 05, 2009, 10:44 PM	#8
peteapilot The Truth is Not Forgotten Join Date: Feb 2008 Location: Hotchkiss Co. Posts: 262	I have been working with a wooden joiner wrapped with cf. sock 2 layers.You can sand down or build up to get the fit you want.Cabenit grade clear hickory or ash is the best ,and any shape will work if you take time to fit it. Suck it down with heat shrink tubing for the lay up

Nov 05, 2009, 11:28 PM	#9
Soar_dude SSP#14 aspirant Join Date: Feb 2002 Location: Fort Lewis, Washington, United States Posts: 1,214	Oh I like that idea about using a sock and heat shrink! Now I need to check if they make them in fiberglass or kevlar to act as abrassion barrier for the Carbon fiber.

Nov 06, 2009, 11:40 AM	#11
mlachow Registered User Join Date: Oct 2005 Posts: 722	If you are using solid aluminum rod, then go with a tube, or steel tube. Not sure how much weight you are trying to save and why. When you get to larger sizes, then hollow tubes will be best for weight savings. For the most part, the inside of the rod is just going along as excess baggage.

Nov 07, 2009, 02:03 AM	#13
prodjx Registered User Join Date: Jan 2007 Posts: 1,346	I'm not so sure carbon can be extruded, does anyone know for sure?

Nov 07, 2009, 10:42 AM	#14
Soar_dude SSP#14 aspirant Join Date: Feb 2002 Location: Fort Lewis, Washington, United States Posts: 1,214	Carbon fiber extrusions are made by pulling resin impregnated tow thru a form then removed once it cures. I am sure someone on here knows the exact process.

Nov 07, 2009, 11:46 PM	#15
schrederman Hotdog Glider Pilot Join Date: Nov 2002 Location: Clovis, New Mexico Posts: 4,264	Back when I owned an interconnect business, one of my customers made composite extrusions. The rovings passed through a mold that was about 2' long. The resin was forced in at the beginning and the extrusion came very slowly, fully cured, out the other end. They were pumping some form of lubricating agent in at about the halfway point in the mold. The mold was heated and it stands to reason that they were using a special resin formulated for this application. The coolest part was the tape wrap that was formed around the rovings by rollers as it all passed into the mold. What I saw was an 8" I-beam being formed. It moved at about 2" per minute. They made buildings for highly corrosive atmospheres. There was about 15' of the beam sticking out of the finished end of the mold when I saw it.