Carbon Fiber Pistons. Opinions please.

[nova]

Ok, first a little back story.

I'm currently employed at a University flight research lab.

Raspet Flight Research Lab

One of the main aspects of our research is in the area of composite materials. We regularly make various aircraft components out of various carbon composites consisting of carbon fiber and different grades of resin.

I was in a discussion with one of our PhD. Mechanical engineers (his specialization is materials) today.

He was saying that NASA as been working with carbon fiber pistons in gasoline engines. He didn't know what the properties of the things are.

How do you think they perform in terms of strength, thermal properties, and performance?

What do you think the strengths and weaknesses of such a thing would be?


I also found out through this discussion that as long as I work on my own time I can use the facilites to produce any carbon fiber parts that I can design. Somehow I think I might be adding a lot of carbon fiber parts to my car in the near future.

[WickEdSix9838]

depends on how thick the material is adn what kind of coating they put of them, if i was to guess, i would say they wouldnt work, but there may be some type of coating that can make the carbon fiber withstand the heat? dont know

[Arctc Wolf]

I don't think carbon fiber likes heat much. It's very strong, but the thermal properties aren't very good(I think). Also, this would be more costly than titanium I think. If they are coated so they get better thermal efficiency, they'll be ok. I don't know how they'll take combustion though. Keep us informed of the progress.

[Red V6 Raider]

How about a round of CF driveshafts for everyone?
[img]graemlins/thumbsup.gif[/img] :D :D :D :D

[ July 05, 2002: Message edited by: Red V6 Raider ]</p>

[kaygee08]

<blockquote>quote:</font><hr>Originally posted by Red V6 Raider:
How about a round of CB driveshafts for everyone?
[img]graemlins/thumbsup.gif[/img] :D :D :D :D <hr></blockquote>

What he said!!!!!

[Dominic]

The problem with CF is it is a fabric, and its difficult to make any textile work well under extreme pressures. The better materials for pistons would be ceramics, since theyre cheap and readily available - ceramic engine design has been tried over and over since 1973 and its still ongoing.

[V6Bob]

"I don't think carbon fiber likes heat much"

"The problem with CF is it is a fabric, and its difficult to make any textile work well under extreme pressures"

Neither of these are true, even in combination. The F1 boys use CF for brakes (pads and disks, they're called carbon-carbon).

They don't use it for pistons. My guess is either rules or shock loads.

[ July 03, 2002: Message edited by: V6Bob ]</p>

[nova]

<blockquote>quote:</font><hr>Originally posted by V6Bob:
"I don't think carbon fiber likes heat much"

"The problem with CF is it is a fabric, and its difficult to make any textile work well under extreme pressures"

Neither of these are true, even in combination. The F1 boys use CF for brakes (pads and disks, they're called carbon-carbon).

They don't use it for pistons. My guess is either rules or shock loads.

[ July 03, 2002: Message edited by: V6Bob ]<hr></blockquote>

Yeah, you are exactly right. When I say we make carbon fiber parts, I'm talking about carbon fiber composites.

You produces a mold, lay out your carbon fiber, coat it in resin, lay an absorption coat over it, bag and seal it, put it in an autoclave, pull 30in of vacuum on it, and bake it at up to 300psi and 800degrees for however long your resin specs say. What comes out it lighter than aluminum and generally as strong as steel.

I was moving stuff around today and dropped a 50lb steel bar on a test part from about 5ft off the ground. The carbon fiber part did not even crack.

These are aircraft components we build primarily. This isn't like a carbon driveshaft or something where if it breaks you you say oh well and get another driveshaft. They can't even have a .01% failure rate. If they fail, people die.

In the link I posted, the weird looking aircraft that you see is almost entirely CF composite. If I remember correctly it only has about 50lbs of metal in its structure.

The carbon is not what actually burns when you talk about carbon composites burning. Its the resin. You can get resins that withstand high heat. The highest I know of can go up to 1400 degrees F. I'm betting NASA is working with something far better than that. I've even heard about afterburning jet engines being made with CF composites. Temps in a jet engine can be in the 2500 degrees range and the afterburner can be a lot more than that.

As far as I know the reason no one is using these yet is that its really still experimental. If it works well I wouldn't be suprised to see CF pistons show up in Formula 1 in the near future.

I'm thinking I'm gonna try a console first, then maybe a driveshaft. Then if those work OK I might try a hood or something. Then from there maybe replace all my body panels with CF. The stuff can be made smooth and is entirely paintable. I could shed tons of weight like that.

[ July 03, 2002: Message edited by: nova ]</p>

[Wicked98Six]

Damn, what's your job again? How do I get hired? :D

[nova]

<blockquote>quote:</font><hr>Originally posted by Wicked98Six:
Damn, what's your job again? How do I get hired? :D <hr></blockquote>

Believe me, you don't want my job at the moment.

I was working as like a semi-intern for one of the engineers. It was a good job then. He was only on 9 month salary so he packed up and left for the summer.

The shop boss then grabbed me and I've been doing b*tch work like sweeping floors for two weeks. Before that I was working on a project for the Army involving gliders.

I was also told there would be a pay scale implemented where I would recieve a significant raise once I became a sophmore. It hasn't happened so I'm now barely scraping by making minimum wage.

Right now its pretty sh*tty except for the access to custom CF stuff.

[ July 03, 2002: Message edited by: nova ]</p>

[Arctc Wolf]

so, since it can take heat and pressure, what about the stresses found in reciprocating parts. the stretching, compressing, twisting, and such that an engine goes through all the time? I would think it would lose it's structural stability over time w/ all these factors working against it.

[strobhen]

replace your interior plastic w/ carbon fiber... heck, could even get rid of a lot of carpet.

[Seal]

well, if you can have lotsa carbon fiber in your car, you would definatly make it lighter [img]smile.gif[/img] ligher is better [img]smile.gif[/img]

[Red V6 Raider]

How much of a pain in the *** is it going to be to make these carbon fiber parts? I don't suppose you could just take your original piece and throw it in a mold and just replicate it, could you?

If so, helllz ya!!! :D

[nova]

<blockquote>quote:</font><hr>Originally posted by Arctc Wolf:
so, since it can take heat and pressure, what about the stresses found in reciprocating parts. the stretching, compressing, twisting, and such that an engine goes through all the time? I would think it would lose it's structural stability over time w/ all these factors working against it.<hr></blockquote>

It doesn't lose stuctural stability in aircraft wings and those are under a great deal of flexing stress. Depending on the resin used, parts can be slighty flexible also. By using different resins you can make parts with any number of properties. Carbon fiber composites are very versatile materials.

<blockquote>quote:</font><hr>Originally posted by Red V6 Raider:
How much of a pain in the *** is it going to be to make these carbon fiber parts? I don't suppose you could just take your original piece and throw it in a mold and just replicate it, could you?

If so, helllz ya!!! :D <hr></blockquote>

I'm thinking I can do something quite similar to that.

The way we generally create molds is with a fiberglass/resin mold laid over a metal lattice that is then cured in an autoclave for an hour or two. I can probably make the fiberglass layup over the existing parts and let it cure slightly outside the autoclave. Once it has cured somewhat I can then transfer it to the autoclave to cure completely. From there I can layup carbon fiber over the fiberglass, and then cure that in an autoclave.