Forum: F-16 Design & Construction

Most engine blades are a Titanium alloy, with turbine blades having a thermal coating to extend the life of the blade

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I think you can now hold the turbine blades in your hands if you are successful in your bidding on ebay for this secret item.

1 day left
http://cgi.ebay.com/ebaymotors/ws/eBayI ... gory=26439

Come on guys, jet engines, and metalluargy are not secrets. Sure its complicated stuff but you´ll find experts and literature about that on every major technical university.

This is really one weak point of that community.
PPL declaring stuff secret simply because they don´t know or because their manuals don´t explain them in detail

Good post hansundfranz, it's not only the material, but the way they are constructed. Newly constructed turbine blades are made in what is known as single cell construction, allowing no trapped air molecules or dissimiliar mixture of alloys to compromise the structural integrity of turbine blades. Suggested reading: Irwin Treagar, Turbine Enine Technology. Rumor has it ceramics (composites) are now incorporated into turbine blades to prevent disintegration under the most adverse conditions.

"single-cell"? Do you mean "single crystal"? And if not, what's the difference? There's a lot out there on turbine blade materials and construction. I've seem some that left me wondering "how the #$@k did they make that?" and had cooling channels and boundry layers to the degree that they could operate in environments several hundred degrees higher than the melting point of the material. Anybody ever boiled water in a Dixie cup over a fire? You can do it. Obviously you're not going to be doing it with an acetylene torch as the water has to be able to remove the heat fast enough. Anyway, same principle.

I like engine questions...

First off what the blade is made of would be considered competition sensitive... not classified.

Now we need to determine what he has. Let's go with Pratt. Compressor blades are silverish and smooth in color. The first stage blades are about 1.5 feet long by 5 inches deep. the last stages compressor are about 1.5" tall by 1". Fan blades normally have a mid section and a rubber strip on the root. Core compressor blades look like fan blades only getting smaller in each stage without the mid section.

Now, turbine blades are about 1" to 3" long and a inch wide, may or may not have cooling holes built into them. Have a root to mount to a disk like the compressor blades. Normaly have a coating and are rough to the touch. Usualy are brown in color. I doubt that you have a fan stator. A fan stator is huge and looks nothing like a blade. I hope that helps.

Email me the pn on the bottom of the part and I will tell you exactly what you have and the main parts of what its made of. I have a 4th stage compressor blade that I polished to a mirror shine... Awesome display piece at work... *training use only ovecourse*

Yes, it's single crystal (SX) - which means no grains, it is one crystal. If "Irwin Treagar" says otherwise he does not know much about turbine technology.

Also, you are correct it is the process (not so much the chemisty) to produce these parts that is actually what is "competition sensitive" and non-exportable under ITAR and EAR.

Someone mentioned single crystal, I was the one who mentioned the wrong process, it's been awhile, glad someone posted the correct nomenclature. It is casted (the materials) into a mold, (a complex one at that), at high heat and speed. This is how they created the engine airfoils to withstand greater than normal stress/strain/deformation.

Irwin Treagor's book is a good one.

The ones I've seen were investment cast in two pieces. IIRC the partline went around the leading edge, tip, trailing edge with the root being in one piece attached to one of the halves. I don't recall how they are bonded together. The interior channels were surprisingly complex and the holes for the boundry layer air were not just round holes but more like quarter-moons almost parallel to the surface of the blade, somewhat like a cheese-gratter. Bleed air would come in through the root, travel through numerous cooling channels inside the blade and then exit the surface of the blade in such a way that it formed a barrier between the hot efflux of the combustor and the surface of the blade. The thing almost looked like a piece of jewelry.

This is true sferrin, you described a blade perfectly, a piece of jewelry. I was unaware they came in two pieces and I too, don't know how they would be joined.

Old thread but I thought I'd chime in a little on single crystal since I read about it a long time ago and it's very interesting. The metal is poured into a mold and at the bottom of the mold is a continuously smaller channel until you get to one molecule (or close to it!). The crystal is started right there and the metal is very slowly cooled from that crystal up so that as it cools every molecule of the metal becomes the same orientation as that first crystal and the blade becomes one crystal with no grain, weak points, fault lines, etc. (as mentioned before).

EriktheF16462 wrote:

BTW weapons guys have to have special training to be weapons guys, while anyone on the flightline troop can crew.

Yeah, learning how to work as a team....

EriktheF16462 wrote:

Not anyone can load.

You're right, it takes three!!!

Sorry, I had to. No offense buddy! Doh

F16VIPER wrote:

He does not say what engine he is referring to.
In any case all the different materials for both the F110 and F100 are mentioned in Jane's all the world's engines. Do not think that the metal name is secret, maybe the process of how to make the blade out of that metal.

I know someone will provide technical information regarding the alloy made out of craptonite and ballonium

The correct term is proprietary. Each manufacturer has their own blend of alloy's, though it must meet a government standard for performance.
Contractors have what is called non-disclosure agreements with their employee's, that prohibit them from selling or divulging processes, information, or materials. There is statue's of limitations on these agreements, which normally coincided with patient life. Once a patent has exceeded it protective status it becomes public domain.
There are exceptions to the rule, such as RAM which hold a National Security classification which override all other law.
Depending on what his part came from will determine if it is still under patent law (proprietary), public domain or National Security.
Sorry but without more information about the part no one will be able to tell what this part is made of.
Hope this helps.

As to the thought that blades are in two parts, according to a friend in the business of building them this is incorrect. If you are looking at what appears to be a seam, you are most likely looking at the coating that was plated on to the blade.

Last edited by Mushmouth on Jan 29, 2008 - 05:04 PM; edited 1 time in total

Well, to answer the question about the metal that turbine blades and compressor blades are made of, this is from a "F110 Jet Service Report" which are distro'd from our AFETS reps. We get them when ever there is a update or upgrade to GE systems. This one is for HPT Blades and Changes To Surface Appearance. Applicable to GE F110, F118 and F108s. In it, it mentions what the blades are made of and other things. But, at the bottom it clearly states, "GEAE Proprietary Information Competition Sensitive" So, it's not that most people don't know, but most people that know, know not to tell. So you may have better luck finding it out on Wilkapedia or something to find out what it type of metal it really is made of. Whistle

Also, for those that say that I or others that others are BS'ing or really don't know because we won't say, if you're in the military or work for these companies, the you already know better. So say what ya want. Slap

Mush

Hi guys,

the science channel has a episode in "how it's made"
They show you how a blade is made and it might even tell you what kind of material it is.
I thought it was cool to watch

Later

henk

Forum: F-16 Design & Construction

Material of turbine blades