chuntington101

i understand your worries, but you only have to look at the likes of the Lotus elise to see that it does work! over here these little cars get tuned and trashed to within an inch of their lives on the road and at the tracks. people use them for prints and hill climbs and they are still going. infact i have never heard of one falling to pieces.

thanks Chris.

OKcruising

The catch with Aluminum is to make sure it doesnt go beyond its elasticity limits. If I remember, it has a smaller range of deformation in general.
Eh, some 7075 T6 Al is only like 10% "weaker" than Chromoly 4130 on the ultimate... but the Al will weigh less and have a higher limit on where it will deform. But as for welding it, be sure to follow proper guidelines, you want to make sure you bring the metal back up to the mech. properties.

chuntington101

the advantage of ally OKcruising is that you dont NEED to weld it. bonding is very comon and can be better than welding. also cause much less thermal stress.

Chris.

treyZ28

Carbon Fiber

treyZ28

Guys, remember that for stiffness, its not a linear relationship between thickness and rigidity (bending moment). Bending moment for a solid bar is 1/12 * base *height^3

chuntington101

just read an article on plastics on cars. turns out one hell of a lot of car body work is now termoplastics. its great cos they bend rather than dint or crak, are cheap to make, are light and dont rust!

also there is alot of money being spent looking into ways or using fiber renmforced plastics. these would be miles cheaper than the likes of carbon fiber (which has to be built up layer by layer often by hand) and will be nearly as strong!

so it might not be that much longer till you have stressed plastic body pannels!

thanks CHris.

treyZ28

Nissan is already doing it. the front fan box thing is a stressed member and it is plastic.

Composites will make their way into a lot of stuff. We are doing some pretty insane stuff with CMM (carbon ceramic matrix). Basically uses a ceramic in place of expoxy. Incredible strength and temperature capabilties.

As far as frames go, lots of cars are running carbon mono stuff.

chuntington101

i agree!

the big problem with carbon fiber is its just to work intensive! you have to lay up all the stuff indavidualy and then "cook" them.

if they could get the same tech in to these thermoplastics (the ones that never go hard) it would be great. you could mass produce them more like you do with steel. also if you could get the fiber renforment then they would be strong to!

hmmmmmmmmm carbon chassis are soooo good! shame they are reserved for the supercars and race cars at the monment!

Chris.

treyZ28

Yeah, working carbon sucks.
I saw the price of carbon fairings (sport bike) and set out to make my own.
After I successfully made my first one, I promptly bought a produced set. Fortunately, the goal was expeirence/knowlege, not cost savings

raymundojr

i suggest u take aluminum made as it prevents rust build up due to changing weather condition.The same applies to billet grilles of cars.

383LQ4SS

iTrader: (33)

Just FYI...aircraft are generally made from 6061 T6, 2024 T3, and 7075 T6

However...all of our new aircraft (Raytheon) have fuselages made from a proprietary Carbon fiber process. much lighter and MUCH stronger. However they will not tolerate any damage and repair is difficult. And very succeptable to water intrusion. Seems evey material is still a trade off. Good engineering of either material is probably more a key factor.

treyZ28

It's 6061, but it's not the same 60160 you buy at your local metal shoppe

Military aircraft cant use composites. Too fast, surface temps get too high.

chuntington101

i dont think they dont use them cos they go to fast or have high temps. i was told by a BA guy whne i went to view their factory thet they dont use them cos they can tell if there are any imperfection simply by looking at the wing.

for example, if a bird hits a wing and puts a huge dent in it they can easly tell that it hit something and the wing is damaged, then look ito it further if they feel they need to. you cant do this with carbon, it would have to be sonic tested.

now imagine this in a militery situation.....

thanks Chris.

treyZ28

cos?
composite.....

They have some uses for ceramic composite matrix (carbon + ceramic instead of carbon + epoxy) but it is definitely not on the body of the aircraft

OKcruising

I thought the new F22 makes extensive use of carbon composites?

chuntington101

i thought that too! but then i was told that they dont by a BA enginer!

thought i saw a TV show that said the whole of the top of the wings was CF. but thought that might have got changed when in production.

sorry treyZ287, dont quiet get you there. "cos? composites......."

there was some reserch into cermaics and polymers for turbine blades. dont really know if it ever took off (pardon the pun! lol). my dad was a designer for the RB211 unit fitted to the 747 and he said they where working on them back then!

Chris.

treyZ28

I stand corrected- certain areas of the body of plane do have it. The body is still largely metal based. The carbon ceramic matrix's primary use is well...other stuff. The structural parts aren't composites. Some of the "skin" pieces are.

I'm 100% sure the turbines aren't a composite; they are single crystal alloys (nickel based stuff, I assume). Really cool, just dont drop them

chuntington101

haha, your right on the turbine stuff. but there was some development of ceramics.

also worth noting that Ford's WRC rally team had to use a ceramic turbine blades to cope with the MASSIVE egts they where seeing on the stage! 1,000 degrees C was the norm for them.

thanks Chris.

treyZ28

I'm more involved with the powertrain side of things than the plane itself, so my info on the body pannels might be a bit dated.

MrDude_1

iTrader: (4)

LOL
this may be a shock to you then.

the front fenders, and doors of 4thgens are fiberglass reinforced plastic.
and the hood of my 82 camaro was SMC.. Sheet Molded Composite.
almost every new car on the road uses plastic bodypanels of some sort.... ever notice how most 4thgens are pretty straight except for the back part, even when they're 10+ years old?
thats because the outside of the car is all plastic (urathane bumpers, plastic doors/fenders) except for that rear tub.. thats the only area that can be dented.

same with vettes.. they've been made out of fiberglass/plastic/composite ever since the first vette in the 50s.