ColinM

A couple of friends and I are planning to build a large Carbon\epoxy jet aircraft, powered by a JetCat engine. Part of the design of this aircraft calls for a bifuracted exhaust system top take the engine exhaust out of the sides of the aircrafty and we'd like to mould this from carbon fibre. Anyone know if there is a carbon fibre resin system that can cope with the exhaust temperatures we're likely to encounte?

davidfee

Normally bifurcated turbine exhaust ducts seem to be made from thin sheet stainless steel. This is for good reason... the exhaust temps on a turbine are HOT!!! The carbon fibers can probably take the heat, but I doubt that you will find an epoxy system which is up to the task. I don't think even NASA has such a thing. They make a carbon/epoxy part and then bake it to convert the epoxy to carbon. They call it "carbon-carbon." They use this stuff for high-temp parts like shuttle leading edges, etc.

-David

Darrinc

My Feedback: (5)

There is always RP-46. It is a polyimide resin that normal operation temp is 650°F and can spike up to 1500°F.

But then it is $5000 a quart. Oh and you need to be able to cure it at 615°F @200psi for 12 hours. You also need to purge the oxygen out of the autoclave with nitrogen because the air inside will burn at those temps. It is a lot of fun to work with since it has about a 50% methanol carrier which flashes off in about a minute and leaves you to deal with a molasses type of mess.

On the positive side, good old inexpensive RAM 225 mold release works excellent with it. You just have to bake it on at 650°F.

SKYPYRO

They've got RP-46 at my local Walgreens, right Darrin?

Or of course, you could go the aerogel route. It is 99.8% air, and only costs $200 per cubic inch. This stuff doesn't let any, and I mean ANY heat get through.

On a serious note, I think David's recommendation is the best. Most turbiners use stainless steel to make their exhaust ducts.

Dan

Gowge

Colin, you might be able to build that from Titanium Tubing if you need something lightweight but strong... What diameter tubing do you need? It's available over here, but hard to find in exact diameters & wall thicknesses to suit.

Try [link]http://www.onlinemetals.com[/link] They have titanium tubing scrap sometimes at (relatively) very low cost. They also offer very thin stainless steel tubing that might work for you....

[link=http://www.onlinemetals.com]ONLINE METALS[/link]

[link=http://www.onlinemetals.com/specials.cfm]SPECIALS & OVERSTOCK @ ONLINE METALS[/link]

GOOD LUCK!

Bruce Thompson

Phenolic resin will take 900 degrees and is cheap. It works like epoxy or polyester. My problem has been getting someone to sell less than a 55gal drum of it to me.

mattyd

We use Phenolic resins around the exhausts on our race cars even at that temp it destroys itsself just use thin metal will be easier