Plus all the parts on a Glock that matter are still metal. The barrel, chamber, slide, firing pin, etc are all still metal. Just the frame is polymer, and honestly you could make the frame out of wood and it would still work (like old school pistols).

Glock handguns are an example of what you CANNOT do with plastics more than anything else.

 

You must have missed the part in the article where it states they were not talking about making the engines entirely out of plastic, put using metal for sleeves and crankshafts, etc. Just like the Glock.


And we can talk about how inefficient an internal combustion engine is, but some day we may see a hybrid that that throws a Stirling engine in it too. An engine that turns excess heat into power.

Dean Kamen, the inventor of the Segway has been working on perfecting a Stirling for some time.

http://alfin2100.blogspot.com/2009/05/dean...ing-engine.html


Kamen is so cool. The Segway is not quite what he made it out to be, but a guy that is just obsessed with inventing things and finding new technology to solve problems is just awesome. Plus, any guy who hops in his helicopter every morning, turns on the theme to Star Wars and flies to work is cool in my book.

If this little stirling engine can run off a cup off warm water, you could certainly generate some additional power for moving a car by taking the heat out of the coolant instead of just venting it to atmosphere.
[media]http://www.youtube.com/watch?v=cqmeYc8GWmA [/media]&feature=PlayList&p=4AA8E4EB073924A5&index=1

 

Wow, interesting. Thanks for sharing.

 

[QUOTE=JonBoy,Dec 1 2009, 11:02 AM] I agree with your points as delivered but question the feasibility of complex internal latticework in a motor.

 

Im an avid shooting enthusiest and do own a modifed glock pistol. Go on you tube and watch a Glock, any glock being fired in slow motion. The frame absorbs a ton of kenetic energy and flexs pretty dramatically, the chamber is also not supported and the steel rails sit in the composite plastic frame. There is no autoloading pistol with a wood frame for the obvious reason that the weapon would just shatter. While the frame itself does not directly contain the gas pressure from the chamber combustion. it is a structural member of the mechanism of the firearm. Unlike a wood stock on a rifle, which contains the complete action, (you can fire a bolt action rifle without the stock.) You cannot fire an autoloading pistol without the frame as it contains the trigger mechanism and also absorbs the kenetic energy from the slide traveling in and out of battery.

 

...a couple things to think about...

#1 Plastic (when reinforced by glass and other fibers) can be made as strong as steel.

#2 Plastic will break/shatter instead of bending.

#3 Plastic is made out of fossil fuels, which are depleting and non-renewable. Whereas aluminum is the most common metal found in the earth's crust.

#4 Plastic cannot be disposed of, creates poisonous gas if melted, and does not decompose...

 

Not really and certainly not for the same money as steel/iron. Plastics and fibers have to be interwoven to resist multi-planar loads, which adds both cost and complexity. Plastics handle axial loading very well but it takes a fair bit of work to strengthen them to handle other types of loads (bending, torsion, shear, etc, etc).

It depends on what type of plastic. There are a ton of them that have a LOT of plastic deformation prior to permanent deformation and/or total failure.

Sure, but they are reusable.

But again, they are reusable/recyclable.

 

Sounds like a polyimide with chopped glass fiber might be what he's using, no? Or a traditional epoxy. But those are all $5-10+/lb. Polyimides are great because they have good structural properties and they melt above 400F, so temp isn't a huge issue. But PPS goes for $7/lb, PEI $10/lb, and PEEK is way up there. Aluminum is ~$1.50, and steel is lower. The engineering and tooling costs for composites, esp. thermoplastics, are high as well.

If he can make it out of PP or PET, then we're talking. That costs ~$1/lb. But it melts around the 200s F, and it experiences creep below that.

But besides getting around temperature, another fundamental issue for some parts is that composites experience fatigue damage even under fully compressive load cycles. So as stated before, metals will have their place in motors for a long time, although it's no stretch to think composites could displace some of the weight-sensitive parts.