Owner produced parts - composite or 3D printing - contacts?

Katamarino

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Katamarino
I need to replace a couple of fairing brackets that sit at the bottom of each landing gear leg on the 182. See attached a (not great) picture. Part number 0741642-1.

These seem very hard if not impossible to obtain from a normal supplier. The current ones are metal but it seems like the kind of part which could be made up in composite or even 3D printed if a strong enough material exists. I have the old ones as templates.

Does anyone know of anybody doing this that might be able to help me look at it further?
 

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So I think either of those should be fair game.
While owner-produced is a possible route you'll probably be money ahead by either having your existing ones repaired or locate a used bracket. Also discuss with your mechanic to see his take on owner=produced parts as he will have skin in the game as well. Having assisted in a number of owner parts I wouldn't pursue the 3D print version as it only complicates the equation for a TC aircraft. However, there are other fabrication methods available to produce one of either material. Another article on these parts by Bill O'Brien adds to the one above and is considered the go to reference by most. Regardless, its definitely an option but would exhaust other avenues first especially from a cost standpoint.
 
I have the old ones as templates.
3-D printing would involve first creating a model in CAD - not impossible, but not trivial.

Making a mold (plaster, silicon, wax, whatever (I would go with plaster)) from an existing part to form a fiberglass / resin duplicate would seem to be a much much simpler way to go. Not quite trivial, but hardly complicated.

(I have no idea what is or is not allowed W.R.T. a type certificated aircraft - probably worth consulting with your AI before proceeding.)
 
My AI is the one who suggested this route so I think he's OK with it. Seems like composite might be the way to go if the existing can't be repaired. It's pretty beaten up.
 
3d print a mold and lay it up in fiberglass or carbon fiber.
 
3d print a mold
Assuming that the original part can be pieced together enough to give a reasonable outside surface making a plaster mold is pretty easy. The original part will have less built in texture as well. Modeling clay works well for bringing up the surface to the edge of the part where it doesn't lay flat (when I was an undergrad, we used asbestos... :eek: )
 
If I was doing it for myself, I'd just layup glass right on that part after waxing it with mold release or a quick spray of PVA or both

Another favorite, is modeling clay right on the airplane and glass over it.
 
I don't think, but I could be wrong, but if the part ia available from original manufacturers, you can't make that part. But mosaic may change that. The big reason for the Explosion in experimentals is the cost of parts.
 
but if the part ia available from original manufacturers, you can't make that part.
FYI: no restrictions on what parts an owner can produce regardless if the OEM or others have them available. Most owner parts I've dealt with were made due to OEM high prices or long lead times.

As to MOSAIC having an impact on TC aircraft parts...how so?
 
Do you have a college or university connection with a student or faculty? You could find an engineering student with access to a 3D printer and work with him/her on printing. You perform the measurements and provide the final manufacturing specs. Have them help you do the programming and printing as well. Compliance with owner manufactured part regs. You’d have to find an A&P to sign off on the installation - plastic replacing metal…(edit - I now see you already have a willing AI).

It’s a complex shaped part:

4FF34A33-E0F5-4DA0-8612-92FC0323DA31.jpeg
 
They're asking $3k for a tiny metal bracket. You might be ok with ****ing that away but I try to be a little more careful.
I’m so not ok with ****ing away money I don’t own an airplane.

But that’s me and I’ve been around long enough to know one man’s fortune is another man’s pocket change and how money is allocated varies significantly.

I’m also not able to read minds. Thanks for answering the question. Although I don’t appreciate the condescending tone very much.

Furthermore in your original post you specifically claimed availability as a primary reason for wanting to owner produce.

If you’re that willing to step over a dime to save a penny why don’t you just take off your pants. Let those wheels see sunshine.
 
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I don't think, but I could be wrong, but if the part ia available from original manufacturers, you can't make that part. But mosaic may change that. The big reason for the Explosion in experimentals is the cost of parts.
I don't believe there's anything that forces you to buy a part from the original manufacturer or PMA parts producer.
I've made lots of parts for my Champ, wing tip bows, all the wood stringers and formers in the fueslage. All of those parts are available from other approved sources.
All you need are the drawings and use the same materials.
 
Meglin in the classifieds might be able to help.

I have a 3d printer and could likely make that. I am thinking that's probably not the best solution for this application.
 
I have a 3d printer and could likely make that. I am thinking that's probably not the best solution for this application.
Correct. You do not want to 3D print this part. It will fail almost immediately.
 
There seems to be some confusion on "owner produced" parts. It's not the case that you as an owner can make any part you want and install it. All it means is that you are spared some of the manufacturing authority issues. It's still incumbent on you to show that the part is equivalent to the one you are replacing.
 
It's still incumbent on you to show that the part is equivalent to the one you are replacing.
Which may be a challenge with the structural integrity of a 3D printed part.
 
the part is equivalent to the one you are replacing.
Not so much "equivelent" but the item must conform to some form of approved data. With this item you could try a field approval or find a DER to approve it.
 
In the UK? I'd maybe try to find someone to make it up in carbon fiber. It's not any more difficult to work with than fiberglass, for small stuff not much more expensive, and there's at least one outfit in the UK that sells small quantities of the stuff and has youtube videos on how to work with it. Can't remember the name, but they're pretty popular I think.

That said, I'd leave them off.
 
As for 3D printed parts - don't look at it at the level of consumer or hobbyist work. There are companies (one here in Denver) that does very high-end, at the same level as industrial, machined parts. Boeing's using it for 3D printing for engine vanes, many companies use it for prototyping and serial production of parts.

The downside - it's probably cheaper to spend the $2K from Cessna! These types of industrial printers start in the hundreds of thousands and go up! We have a hybrid unit on the first floor of my office building (Computer Science and Industrial Design depts) and it's huge.

Start here for details on what's possible and estimates.


Disclaimer - I know nothing about the company, nor is it the printer we have in the building. If I had privs to the one downstairs, I'd make the part for Russ.

PS - if you read the article, there's a section on 3D for dentistry. My dentist has one, and where it previously took 1-2 months for the lab to make a crown, he does it in 90 minutes.
 
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Guys here is a nice writeup about Pilot/Owner Produced Parts:



"There are some other limited exceptions for what the FAA refers to as “standard” parts, such as nuts, bolts and other hardware manufactured under an industry standard such as AN (Army-Navy) or MS (Military Standard), or parts manufactured by a repair station.

There is one major exception to the FAA’s tight grip, and that is the owner produced part. Owner produced parts are commonly used by the airlines, which often have a large fleet of the same or similar types of aircraft................."
 
Correct. You do not want to 3D print this part. It will fail almost immediately.
Not necessarily. There are a lot of options nowadays for 3D printing. ABS is probably the most common, and a lot of Cessna trim parts were made from thermoformed ABS. But you can also 3D print (admittedly not on a hobby level machine) in nylon, polycarbonate, stainless steel, all kinds of things.

It doesn't look like a difficult part to make a 3D CAD model of (bearing in mind that it's what I do for a living).
 
Not necessarily. There are a lot of options nowadays for 3D printing. ABS is probably the most common, and a lot of Cessna trim parts were made from thermoformed ABS. But you can also 3D print (admittedly not on a hobby level machine) in nylon, polycarbonate, stainless steel, all kinds of things.

It doesn't look like a difficult part to make a 3D CAD model of (bearing in mind that it's what I do for a living).

My primary concern is not the material. The filament directions you’d have to use would be nearly in the same direction as the existing crack. IMO that’s 100% guaranteed to crack again immediately.

3-D printing a mold would be a better use of the machine. But outside of doing that for fun you are getting pretty close to what it cost for the retail part in effort.
 
This could be done as a weldment, too. My metalworking skills aren't good enough to make that out of one piece, but I could do it with two pieces of mild steel, once for the round part and one for the rectangular sort of shape. Somebody with better welding skills could easily do that with aluminum.

But...if you pay someone to make it, and they bill their time right, I think it's going to cost as much as the part off the shelf, no matter what the process. That might be how they're pricing it.
 
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