Titanium Propellers- Please help
 

Just curious- Aside from cost, does anyone know why airplane propellers aren't made out of titanium?

The lack of elasticity.

If you are at an airport and look into the front of any of the large turbofans, you'll see the giant front fan with anywhere between 32 and 42 blades. Each blade weighs about 15 lb. on large engine and is approx. 24" in length. The blade was made from a solid block of titanium in most engines and it costs well over $25,000. to make.

Titanium is a perfect material for this application.........strong and relatively ductile. The blade won't fracture if the engine hits a bird at 300 mph.

The only reason that it's not on the Cessna is cost.

What are current Cessna and or other light aircraft propellers made of? Aluminum? Carbon fiber?

Common props are aluminum, wood and more recently, carbon fiber. I don't know if c/f is certified for use in certificated aircraft yet but there are Light Sport aircraft and Experimentals with them for sure.

The pictures I see of belly landing results show prop tips bent back. I'm guessing wood doesn't bend even at those rpms so none of those props were wood. I don't imagine carbon fiber or many composites bend either. Maybe ductility is a design factor or FAA requirement.

Sixto
87 300D

Anybody see the show about the GE90 115B? http://www.geae.com/engines/commercial/ge90/ge90-115b.html
Carbonfiber fanblades, with titanium leading edges. The blades themselves are curved for more volume. Quite impressive it is!
Some more info....http://en.wikipedia.org/wiki/General_Electric_GE90
And a closer shot of those beautiful blades http://en.wikipedia.org/wiki/Image:GE90_dsc04644.jpg

Looks like a shredder!:eek::cool:

GE took a leap forward with the GE-90 that no other manufacturer would do. The risk of carbon fiber on a fan is significant. Typically, it doesn't have anywhere near the impact resistance of titanium. However, the compelling weight benefits on such a large engine were irresistible for GE and resulted in reduced weight for the entire supporting front end of the engine. With an engine that has a weight of about 17,000 lb.........every lb. is important.

To date, there have been no GE-90 fan "incidents" that I'm aware of.........a tribute to GE's design and rigorous testing.

I thought that some of you "prop heads" would enjoy this

RAF Sheppards Pilot to Safe Landing

No mention of how they plan to clean the pilot seating.

$25k for one blade.. nice

Aren't the blades investment cast? Titanium is not easy to machine.

Wow!

Brian,
That the GE-90 was a breakthrough use of fiber is a surprise! CFAN is just south of Austin and it seems like it's been there for a zillion years so I was under the impression carbon fiber had been used in turbofan applications for quite some time. Learn something new every day.

Yes, I'm sure they start with something less than a full block..........the machining of a complete block would definitely take forever.

Some of the new blades are cast with a hollow core. That's quite a feat.............