combustion chamber
 

Hi, is their any reason why titanium cannot be used for a turbine combustion chamber.

RE: combustion chamber
 

No other than price and much harder to work with.

RE: combustion chamber
 

Titanium is very brittle to work with, and cost prohibitive when compared to something like stainless steel.

RE: combustion chamber
 

There must be other reasons. I have worked on several full size engines, and titanium have always been used only in the cold parts of the engine.
From Wikipedia: "Titanium burns when heated in air 610 °C (1,130 °F) or higher, forming titanium dioxide."

Lars

RE: combustion chamber
 

Titanium will burn fiercely, but I'm not too sure about the different alloys.

RE: combustion chamber
 

Haven't used stainless Steel for a numebr of years. Incolnel is the way to go.

RE: combustion chamber
 

My wife works for a full-sized engine manufacturer (engineer) with compressor and turbine components so is pretty familiar with these things.

1) As was said before Titanium, and it's alloys, are combustible.
2) Most Ti alloys loose their strength properties above 300-500 F, well below combusion temperatures. Inconel or other nickel alloy is the material of choice for combustion chambers and downstream components exposed to high temp air. Ti is used strictly in cold-end components like compressors that need high strength/weight ratios at low temps. Model turbine compressors can get away with aluminum compressor components.

RE: combustion chamber
 

Why not make small model engine compressors out of magnesium alloy? If its good enough for the koennigseg hey why not...

Its a weak material i know, but when alloyed it can be fairly light and strong. Any takers?

- Dan

RE: combustion chamber
 

Well, you answered your own question with the pharase "make the compressor". You would first need to talk the automotive turbocharger companies into making the wheels from other than aluminum. ALL model turbine compressors (with the exception of the Hawk) are from auto turbos. If you want to make one for our use be ready to add $500 to the price of an engine. Scott

RE: combustion chamber
 

Actually, there are several manufacturers that are using home brewed wheels these days.... Jets-Munt, Jet-Central and even Wren I believe all use their own compressor wheels for some classes of engines.

RE: combustion chamber
 

They only reprofile existing compressor wheels. Like GSR wrote the only manufacturer that mills their own compressors is [link=http://www.hawkturbine.com]Hawk turbine[/link].

As to why not mill out of Magnesium... Well it's weaker and can be a pain to work with. With the compressor being less than 5% of the weight of the engine the savings would be negligible.

Oh, and there's always the risk of a fire after a crash. [8D]

RE: combustion chamber
 

OK, hopefully just to clarify.......Both Jets Munt and Jet Central are using their own cnc wheels, these are not reprofiled existing wheels but 5 axis machined from solid using aerospace grade alloy to their own cfd designs then clear hard anodised.

The Merlin 170, Rhino 170 and 10kg Merlin 90 all have these type wheels.

As an asside they also cast their own hot end inconel parts.

Hope that helps.

Rob.

RE: combustion chamber
 

Who is "they"?

Dave

RE: combustion chamber
 

'They' is Jets Munt and Jet Central.

Rob.