Carbhinge

anybody out there have any experience or knowledge about the Carbhinge replacement for aluminum hinges??

 

Enquiring mind wants to know!!

anybody out there have any experience or knowledge about the Carbhinge replacement for aluminum hinges??

I do now! http://www.carbinge.com/carbinge1.htm

 

Looks like an interesting upgrade/expense to the folded piano hinges, but questionable benefit over an extruded piano hinge. Still, I'm glad I know about them for when I cross this bridge.

 

Anyone else have any real experience or more knowledge on the product?

Looks luverly, but about twice the ASS price for a canopy hinge.

 

The wax a bit about how good it is for cowling attach. I note discussion in other fora about how cr@ppy the result of bolt & nutplate called for in the Cozy is, and this looks a lot better. Less likely to put anything (smaller than the full cowling) through the prop as well. They explain the process well in regard to attaching wingtips to something.

 

I haven't really paid attention yet to the debate on teflon lined hinge pins, this could be an alternative to that also, but don't know the cost comparo.

I used the Carbinge in the rudders. They were easy to work with as far as cutting, shaping and what-not. I didn't use them for the ailerons, as I wasn't so confident they would stand up to aileron flutter. They are brittle. But the rudder areas rarely experience that (from what I hear). Plus, if there was a failure, it would be easier to land without a rudder than an aileron.

Overall, I think they are a quality product.

 

Also.. You get a few more slivers in your fingers working with them... but they're easier to pick out than glass, 'cause you can see 'em.

I wrote the following e-mail to John Barrett @ Carbinge:

 

From: Jon Matcho

Sent: Saturday, May 07, 2005 7:39 AM

To: 2thman@olympus.net

Subject: Carbinge for a Cozy Mark IV aircraft?

 

Hello, I host a discussion forum for composite homebuilt canard aircraft and we have a discussion going on regarding your Carbinge hinges. After a second look, I think they'd be a great product, and something I would consider for my own aircraft.

 

The question is -- can the hinges be used for the control surfaces? Ailerons, elevators, and rudders? One builder is using them for the rudders, but was hesitant to use them for anything else. From what I can tell, they're only used in a trim tab on a Lancair IV P. Why not everywhere?

 

You can see the discussion here: http://www.canardzone.com/forum/showthread.php?t=1278

 

Thanks in advance,

Jon

This is the reply:

 

Jon,

 

Thanks for your inquiry. My IVP has about 4 inches of aluminum hinge - they are in the fuel tank anti-slosh doors only. The only reason they are there is because I had not developed Carbinge when I installed them. Every other hinge in the aircraft is Carbinge. As you probably know, the control surfaces are on bearings rather than hinges, but the gear doors, the cowl, the trim tabs, winglets and all access doors have Carbinge. I wouldn't have it any other way.

 

On our website you'll see that the rated load for the hinges is 3000# per foot with a limit load of 6000# per ft. This means you have a 100% safety factor and that's just to distortion of the pin, not structural failure.

 

I think you can deduce from this that Carbinge is ideally suited for any hinging need in your Cozy Mk IV. We have other customers who are using Carbinge for hinged control surfaces. As long as your control surfaces are balanced and do not experience flutter, there's no reason why they would perform any less than ideally with all the benefits over aluminum they provide anywhere else on the airplane. Aluminum presumably would fare no better in flutter than Carbinge.

 

Early on, I was reluctant to recommend Carbinge for control surfaces, but as we have acquired experience and testing data, we are now confident in the suitability of Carbinge for this type of application. We look forward to providing our superior solution to the hinging needs of the builders of this interesting aircraft.

 

Jon, I hope this helps. Should you have any further questions, please feel free to email or call. My phone # is 360 301 1066.

 

Also you have my permission to quote me on your discussion forum. If you'd like to add me to your address list, I would be willing to answer any questions your colleagues may wish to pose. Alternatively, if you pass on my email address, they are welcome to contact me directly.

 

Regards,

John Barrett

Barrett/Garrett Enterprises, Inc.

PO Box 428

Pt. Hadlock, WA 98339

www.carbinge.com

Is anyone aware of a problem using the Carbhinge with 'in-skin' type copper foil antennas? I understand that a clearance must exist between the foil and any existing carbon fiber.

Anybody aware of that spec?

I do not clearly understand your question, at least what you're intending to do.

 

If the antenna is not touching carbon, then you have no issues with mixing carbon and foil.

 

Speaking of 'carbon', it keeps your plane light in two ways:

• it's lighter than fiberglass
• your wallet will be lighter from all the money not in it

Hope that helps!

.....therein lies the mystery, Jon.

Is not touching good enough or do I need 2 inches of clearance, 4 inches........

I'm pretty early in my build and hope that someone with some expertice (or expertice at the expense of experience) might have some insight.

 

I posed the same question to rst-engr.com and got this response:

A. The original EZ had no carbon fiber.

 

Not all that helpful.

My understanding is that you do not want to COVER any antenna with carbon fiber cloth. Substituting carbon hinges for metal hinges should have no impact on your antennas, if I understand correctly.

It is not a distance thing. Fiberglass is invisible to the radio waves. Carbon Fiber is not.

 

If you put a comm ant on a normal Longez tail, the antenna can see through the entire tail. If the tail was carbon fiber, you could lay the copper foil on top of the carbon fiber and then put a layer of fiberglass to hold it in place. The ant will still be able to see----but only on that side of the tail.

Among the questions I have are how does the hardware fail and how fast do the hinges fail in flutter? I would want to be sure that I could easily detect during the aircraft walkaround I could spot a problem long before a repair wpuld be required.

I talked with a couple of Berkut fliers about possible radio interference as a result of the presence of cabon fiber (which they have a lot of) and the use of copper foil antenna in the winglets. It seems that they are experiencing no problems there.

I gotten the full gamit from no problem to 'you'll go blind if you do that' (well maybe not that bad.)

I'm going to go with the guys that are flying it.

My winglets will be glass with carbinge hinges (which should be shipping to me today.......John's been on vacation.)

 

Because cabon fiber is '8 times stronger than aluminum' and the technical data I've seen on their web site and other sources.........I'm planning on using it wherever I can (including the cowl attachment.)

 

It seems to be a great product that is more in harmony with the composite environment than aluminum.

Did the Berkut flyers put carbon fiber directly over the antenna or did they put the foil on top of the carbon fiber and then put a layer of glass on top of that?

Neither......The winglets were glass and the existing carbon in the wings and such did not cause a problem.

Drew, I think maybe I may have received some misinformation initially which caused me some concern.

The simple answer is to think of carbon fiber as metal (as was earlier stated by many of you in this thread.)

In other words, it blocks RF, conducts current etc.

 

(1) If the winglets were aluminum, you wouldn't stick a copper foil antenna in it or on it.

(2) The original plans called for aluminum hinges (obviously a metal) which did not cause any RF problems.

 

I was talking with John Barrett last night and he confirmed the same.

 

I like the idea that the Carbinge will expand and contract at the same rate as the rest of the composite structure unlike aluminum.

 

I'm also entertainig the idea of using Cabon Fiber to fabricate my hidden belhorns as well. Something to mess with while I'm waiting for the large layups to cure. I'm not looking to cut weight there but instead avoid corrosion issues with parts that are hard to eyeball on a frequent basis.

The mixed metal of that design doesn't help that issue.

I like the idea that the Carbinge will expand and contract at the same rate as the rest of the composite structure unlike aluminum.

Unless the rest of your structure is carbon also, it won't. Carbon fiber has a thermal expansion coefficient close to zero. Aluminum's TCE is closer to glass fiber than carbon's is. You may like the carbinge for other reasons, but this won't be one of them.

Carbon fiber has a thermal expansion coefficient close to zero. Aluminum's TCE is closer to glass fiber than carbon's is.

Hmmmmm.......well I'm just going off of the manufacturer's specs:

Coefficient of Expansion: metal expands & contracts at greater rates than composite materials resulting in warping, crazing and cracking of bonds during thermal cycles. There is little expansion or contraction of carbon or fiberglass during thermal cycles and the deformation that does occur is more uniform across similar materials (composites) vs. dissimilar materials (metal attached to composite).

Coefficient of Expansion: metal expands & contracts at greater rates than composite materials resulting in warping, crazing and cracking of bonds during thermal cycles. There is little expansion or contraction of carbon or fiberglass during thermal cycles and the deformation that does occur is more uniform across similar materials (composites) vs. dissimilar materials (metal attached to composite).

That's nice. Let's look a the #'s:

 

6061 Aluminum CTE: ~13 x 10^-6 in/in/deg F

 

Carbon CTE: ~1-2 x 10^-6 in/in/deg F

 

Fiberglass CTE: ~8 x 10^-6 in/in/deg F

 

So, you tell me, which is closer to fiberglass - Carbon, or Aluminum?

 

These are approximate, but there's clearly no major advantage to carbon over aluminum with respect to joining it to fiberglass from a CTE perspective, whatever the manufacturer of the carbinge says. Now, if you're joining it to carbon, then it's clearly better from a CTE perspective.

....looks like Carbon by a nose.

 

Anyway, I've checked out Jerry's install on his site and it looks like there are a lot of good things about this product.

Anyway, I've checked out Jerry's install on his site and it looks like there are a lot of good things about this product.

Since my site was referenced, I thought I'd give my 2c.

Really, there are only 2 positive reasons to use the Carbinge:

 

1) They are really easy to shape when trying to fit the in a tight spot.

2) They won't give the famous "Dirty Weeping" lines

you eventually get from AL hinges.

 

That being said, here are the negatives:

 

1)When shaping them on the grinding wheel, you get lots of slivers.(But they're easy to see, unlike fiberglass. So, this is only 1/2 point. )

 

2)They are brittle. Serious flutter might snap them. I wouldn't put them in the ailerons for that reason.

 

3) If I remember correctly, they were more expensive than AL.

 

4) Because of their brittle nature, I would not feel comfortable using fasteners alone. As seen on my site, I used Clickbonds, (The same method described in the ailerons section.), in addition to epoxy to affix the hinges. I just didn't feel safe using epoxy on the hinges alone.

 

The BIG question: Would I do it again? Probably not.

 

If I ever need to replace them, I'll have to grind the old hinge away to make room for the new. Not a BIG pain, but a pain never the less.

 

IMHO, the Carbinges are excellent for fastening cowlings and hingeing small doors and areas that have curves, but not the best choice for control surfaces.

 

FWIW,

....looks like Carbon by a nose.

You must have some special form of mathematics with which I'm unfamiliar.

 

Even using 2E-6 for carbon, 8-2=6E-6 for the fiberglass/carbon differential (7, if you use 1E-6 for carbon), whereas you get 13-8=5E-6 for the fiberglass/aluminum differential.

 

Closer numbers is better (less is more) - you'd like the CTE's to be the same to minimize thermally induced stresses.

 

The point is that carbon is certainly no better, with a fiberglass substrate, than aluminum, and probably a bit worse.

 

Of course, since no aluminum hinge on a VE, LE, COZY, etc. has ever come off due to thermal issues, the whole argument is silly. I was pointing out that one of your rationales for carbinge usage is not correct. The rest may or may not be.

yes.....some of the others benefits are of great interest, especially the 'keeper' they use to set the pin via an a set screw. I like Jerry's application a lot (what a craftsman that guy.) Seeing as I intend to use the hidden belhorn, I'll need a way to inspect those areas. This pin setup allows for that.

 

Bottom line......I won't have the product in my hands until next week. Once I do, I may be of a different opinion.

 

I do appreciate everyone's input.

I'll publish my results once I've worked with this material.

, especially the 'keeper' they use to set the pin via an a set screw. I like Jerry's application a lot (what a craftsman that guy.)

Aw, shucks. I'm a better plageurist than a craftsman. (Just ask the CozyGirrrls.)

, Seeing as I intend to use the hidden belhorn, I'll need a way to inspect those areas. This pin setup allows for that.

Actually, the pin setup is of no help in this area. The pin/keeper arrangement evolved from the need to install/remove the rudder while using ClickBonds to hold the hinges. With CB's you have to use nuts on the inside of the rudder rather than screws on the outside. There is NO WAY to get a nut on the top hinge CB's without seriously hurting yourself, even with the rudder fully deployed. One of my goals was to have as few fasteners visible as possible. CB's allow that, with the pin/keeper modification.

 

This is a pretty good example of how one change from plans can come back to haunt you. Buyer beware! (The CB mod is ONE mod I would do again...... so far.)