anyone know about jet turbines?
 

Recently ive been kicking around the idea to attempt to build a smaller version of a jet engine,one of those just for kicks kinda ideas.

But what ive been confused about is in all the material ive read on the engines ive had some conflicting info on if the compressor blades spin freely from the or not? and if not what parts might i have this mistaken with? Also what is the best way to control the speed of rotation? Im assuming its mainly based on the amout of fuel being delivered to the combustion area?

thanks,
ian

see here:

http://science.howstuffworks.com/turbine.htm

http://www.rolls-royce.com/education/schools/gasturbine/default.jsp

http://www.rc-airplane-world.com/model-jet-engine.html

Le Roux

A few thoughts.......correct me if I'm wrong.

1. I've read that somewhere around 80% of the thrust from a "Turbo-Fan" jet engine is from the fan/compressor blades, 20% from the hot expanding gases or jet plume.

2. Heat, materials and cost will keep this a paper project for a very long time, machining cost might be kept in check DIY.

3. Ducted propellers & fans driven by piston engines might get you 80% of where you want to be. I read about some guy in Florida working on a light aircraft piston driven jet type fan. Read about it in "Kit Planes" about eight years ago.

4. Let us know what your research on this topic yields, interesting subject.

5. You might want to check out over the counter products, do you really want a flame thrower? Would you rather have an axle spinner?

6. Picture below is food for thought.


http://forums.pelicanparts.com/uploa...1123591092.jpg

Most of the power produced by microturbines is in the shaft, not as a result of thrust. Smaller engines all the way from micros up to PT-6 engines and larger use the shaft output as the primary method of producing power through the rotation of a propeller (turboprops). This is not to say the thrust is useless, just it doesn't represent the majority of the power produced by the engine. If you're looking for a thrust-based turbine, it will likely need to be far larger and probably impractical.

Check these out for small turbines....real ones http://www.usamt.com/

I've poked around that site, are they really turbines? What's a "coreless motor"?

Williams International makes small cruise jet engines, doubt you can get much information out of a privately owned military contractor though.

At some point recently, and perhaps still today, there were three counties with the technology and the manufacturing prowess to make jet engines. Good luck competing with America, USSR and France. Oops, I guess Great Britain makes them too. But the point is that these engines are not like a Briggs and Stratton.

Pluse jet engine plans is what I typical see advertised as the do-it-your-self path.

Here is a RC model with them.

http://www.jimohalloran.com/old/phot...rdpulsejet.jpg

I found this site with many designs for sale:

http://www.gas-turbines.com/plans/index.html

I know a lot of fellows who fly model airplanes with turbine engines.

What is the purpose behind your project? These deals are pretty simple in their complexity. Computer controlled and run on real jet fuel, sound like the real thing and act like the real think. Mainly because THEY ARE!


They are pretty darned cool too.

Actually Rolls Royce in GB is one of the largest manufacturers, but there are others in Italy, Canada, and a few other countries not mentioned, parts are outsourced everywhere from Mexico to India. Big companies like GE, Pratt, and Siemens have been buying up all the smaller manufacturers.

Building your own gas turbine engine is a novel idea but very, very impractical, unless you have degrees in combustion, aerodynamics, heat transfer, materials engineering, mechanical engineering, manufacturing, etc it could turn out to be a very frustrating hobby. You may be able to put something together that spins but turbine manufacturers employ hundreds of engineers for a reason, and all of their new designs are based on decades of past experience.

Here is a website that may help.

http://www.ueet.nasa.gov/StudentSite/engines.html

http://forums.pelicanparts.com/uploa...1123635190.gif

Or you could just cobble something together out of an old turbocharger and a propane tank.

http://www.nickhaddock.co.uk/jetgallery.htm

http://www.aardvark.co.nz/pjet/faq.htm

You can even use them to cool your beer.
http://www.asciimation.co.nz/beer/

Tom

Rpm control, still the important part. Those ex-turbos are scary.

Lane

:D :D


For out of the box thinking and to do work in a new area of jets, look to the sea............................

http://www.newscientist.com/article.ns?id=dn3321

there's always this insane guy as well
The turbine is the smallest of his projects, railguns are his specialty

http://www.powerlabs.org/turbine.htm

The Bede BD-5J used s 'real' turbine.....as in a propulsion turbine, not a modded APU...this site is pretty good on the BD-5 generally,http://www.bd5.com/

http://www.gasturbine.pwp.blueyonder.co.uk/TRS18.htm shows the type of engine commoly used by BD-5s etc.


Williams make GA turbines as well as smaller versions for cruise missiles (that's how they started out)

well there is some good info in there but what i was asking was;

But what ive been confused about is in all the material ive read on the engines ive had some conflicting info on if the compressor blades spin freely from the or not? and if not what parts might i have this mistaken with? Also what is the best way to control the speed of rotation? Im assuming its mainly based on the amout of fuel being delivered to the combustion area?

and also i understand the basics, and i realize the potential amount of time that could be ate by doing this, but like i said, im interested and what am i going to hurt? other than maybe my eyebrows and other bodily hair from the start sequence :)

You are asking about the different types of jet turbines. There is a free turbine and a connected turbine.

Take a PT-6 made by Pratt and Whitney. I can stand there while the engine is started and hold the prop. The engine will start and run at full power and I can still hold the prop. The prop is connected to a turbine wheel that is "freewheeling" ie, not directly connected to anything. Once it starts spinning due to the exhaust gasses its just as powerful as a normal prop.

There is a Garrett 331 turboprop engine. Much like the PT-6 except this is not a "free turbine" design. The prop is connected directly to the turbine and starts spinning the second the start button is pressed.

There are loads of used APU turbines out there as well as some small jet engines. Many of them are Mil surplus but some are out of commercial jets as well.

I would not try to make my own, the metalurgy is just too far out of the means of someone not in the business and cost would be out of sight...

As well when you get things spinning at 100,000 rpms or better if it comes apart it might just kill you, and not just your eyebrows. I know of one person who was playing with a instrument gyro. Its designed for 4.5 psi vacuum and he put a 80 psi shop air hose on it. Started spinning a bit faster than designed and came apart. Killed him and maimed another person standing at the workbench with debris out of the turbine inside. They are not playtoys...

Joe A

thank you for your input, thats what i was wondering. yes i do understand, basicly my goal is to build one that just runs under its own power (its not like im going to go out and build some jet powered roller skates - though it is now tempting...) i also have a large surplus of mechining tools that i can use after hours, and a lot of the time im up there doing stuff anyway

like i said it was really just something to tinker with, think of it like a inefficiant/impractical space heater :)

or like my pnematic can crusher

EDIT: WOW!!! had to fix the random babble that came about while typing that