How can a student create a gas turbine engine from scratch?

In summary, the conversation revolved around a student's interest in creating a gas turbine engine and the challenges they faced in doing so. They considered building the engine from scratch but realized it would be time-consuming and require advanced machine skills. They also discussed using a turbocharger, but the cost and limitations led them to consider creating a ramjet. However, others advised against it and suggested looking into valveless pulsejets instead. Safety concerns were also raised, emphasizing the need for caution and proper testing procedures when working with gas turbines.
  • #1
LovePhysics
16
0
Hello guys,

I'm a second year BSc aerospace student in Holland, and I'm thinking about making a gas turbine engine. I hope to specialize in powerplants eventually. You people seem knowledgeable, so I thought I'd ask my question here.

Anyway, bare with me a bit... I first thought about making the whole thing (engine) from scratch, but while I was drawing the engine It occurred to me that it might take a long time before the thing gets finished. Not to mention the machine skills it would require to make all the parts. I went and talked to the keeper of our uni equipment center (a place where they have all kinds of machines with which you can do things to metals, like form them, etc), and he said it would a very long time to create the parts if the thing is too large... and that it would be difficult for me to make everything precise because I don't have much experience with the machines... anyhow..

So then I thought I would go with the next thing... which would be to use a turbocharger, for reasons of not being able to get a turbocharger for less than 200 euro (260 USD), I'm not too exited about that either. (hey, I am just a student :( )

So then I hear that some people have created ramjets at home. Has it been done before? How would one go about creating a very fast air input? A leaf blower?

Any help/comment would be appreciated... :)
 
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  • #3
You can also check out Jetzilla.com. They have a lot of valveless pulsejets there. Forget about a ramjet; they only work above 400mph or so.
 
  • #4
Thanks for the replies guys. I managed to get my hands on a 'cheap' turbocharger. :)
 
  • #5
Make sure you're prepared for disappointment, and possibly death.
 
  • #6
Why on Earth would anyone want to make a jet engine in their own house for? :confused:

Why not just make yourself a bomb, same end result.
 
  • #7
I will tell you why. I believe that next to my studies I have experiment with these things in real, to fully understand them. What good is it if I'm constantly reading about how to calculate the efficiency, and I don't know what, if I'm not even able to work with these things in real.

The only two parts where it could go wrong is if the compressor material can not handle ~80.000+rpm and just breaks apart, sending shrapnel everywhere. Or if the combustion chamber can not handle the expansions. Then again, the shrapnel could hit the gastank. Then you have gas in combination with a turbine which has a temp of 1000+ Celsius.

Anyhow, if people like Ohain were afraid to make these things because it could explode, we would not have anything now.
 
  • #8
LovePhysics said:
The only two parts where it could go wrong is if the compressor material can not handle ~80.000+rpm and just breaks apart, sending shrapnel everywhere. Or if the combustion chamber can not handle the expansions. Then again, the shrapnel could hit the gastank. Then you have gas in combination with a turbine which has a temp of 1000+ Celsius.
You have the right idea, but you're not thinking about the practicalities. At 80 krpm, compressor rotors don't just break apart. They explode. Last year we had a turbine disc fail in one of our cells on a small engine and we were pulling metal fragments out of the wall for days. That is why test cells are ugly, brick and mortar lined rooms with very thick windows and doors.

You NEVER keep the fuel containment in the cell with the engine. That stays outside and must have a safety solenoid valve in the line, near the fuel inlet at the engine for emergency shut downs. If that thing starts getting away from you, and it will, you need to have a quick way to shut it down.

There are plenty of other ways things could go wrong. I would suggest you do a bit more reading and research. You need to be familiar with other aspects like dynamic shaft and rotor balancing. You need to understand how the burner operates. What about data acquisition? How are you going to load this engine? Are you going to create/measure thrust?

You need to know how to be safe.
 
  • #9
That reminds me of an incident at Avro while they were working on the Avrocar flying saucer. They had a catastophic engine failure which resulted in quite an inferno. An evacuation of the building was ordered and everyone was heading out. One engineer who was just arriving on the scene strolled in and disconnected the fuel line. End of problem.
I was quite appalled that such a terrific design team hadn't included a fuel shut-off in their test rig. After a bullet-proof containment chamber, that should be the first safety precaution.
 
  • #10
Gt

I understand your curiosity of gas turbines. They are an amazing piece of technology. Its amazing to me that many people do not understand how they work, however they are one of the most simplistic engines, relatively speaking.
I started your little venture about 2 years ago, and see that we thought alike. I wanted to create a gas turbine laboratory for my university. I wanted to build one (machine it) first, then I saw those "pulse" jets, then I went to the "turbocharger" one, and finally to this idea - which I am suggest.
First, don't machine one unless you plan on spending lots of money and you like to have parts fail many times. Second, pulse jets are cool, but you mise well look at a butane lighter because essentially they are the same. Third, the "turbocharger" gas turbine is about the most rigged thing you can do - yes, it conceptually gets the idea across, but if you ever want to do "efficiency" calculations or any kind of calculations in that fact, don't go with that kind.
Now this is what I ultimately decided to do - however, funding became an issue. There are several companies that manufacture affordable Micro gas turbine engines. They output about 100 pounds of thrust (which is plenty for demonstration) and they are electronically fuel injected with an automatic starting. They run anywhere from 600 USD -5000 USD Now this price is REALLY cheap compared to the time and effort of building one.
Here are the websites to research these.
http://www.jetcatusa.com" [Broken]
http://www.pstjets.com" [Broken]
http://www.amtjets.com" [Broken]
http://www.tamjets.com" [Broken]

So, see what you can get your hands into with these, I suggest going this route. Hope this helps,
Chris
 
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  • #11
Well, I do appreciate all the worries and suggestions, and I will take more safety measures to protect myself and others.

As far as 'data acquisition' is concerned. I sure do want to do that, but I'm still in the dark on how that has to be done. I don't have access to expensive equipment that can measure things in such extreme temperatures. So I'll have to look into cheap alternatives.

Who wants to calculate things on a worthless engine (thrust/weight wise) you would probably think? I see this as my first step on the road to building the whole thing from scratch. I eventually hope to hand build every part of the engine, but that's probably years away from now. All I want to do now is get a first experience with these engines.

The only way (for me) to get a firm grasp on jet engines, is to make them myself. That's a reason I would not buy a ready micro one. I think it's sad & pathetic that aerospace universities/faculties do not have their own jet engines to work with in a proper environment. (They don't in Holland).

So anyway, I'm not looking into making a 'good engine' yet, I want a working one with which I can 'experiment'.
 
  • #12
Yeah, I agree totally. The only real way to get a firm grasp on jet engines is to build one.. However, a lot of things have to go right for a gas turbine to function continuously.. and it will be extremely frustrating and very time consuming. I know for me... producing results is a huge movtivating factor when working on a project (I tend to rush things, very bad habit) .. and I know that building one of these from scratch can take all your time and energy and never really produce a running engine. I am not trying to discourage you from building one. I am just giving my advice on experiences.
Also, since gas turbine engines are very hard to come by (as you say at the universities in holland) having a running one around not only motivates you but others as well to build one from ground up. When having people excited about your project around you... is another crucial motivating factor.

Chris
 
  • #13
You can easily get a thorough grasp on jet engines without building one.

Fred, you're an industry professional. Have you personally ever built a gas turbine engine from scratch, from bits of raw metal to a finished running product?!
 
  • #14
brewnog said:
You can easily get a thorough grasp on jet engines without building one.

Fred, you're an industry professional. Have you personally ever built a gas turbine engine from scratch, from bits of raw metal to a finished running product?!
I doubt it. Read all you want about something as simple as welding. After a year of reading about all the techniques, you still will not be able to weld better than someone who has practiced for two weeks.

Why do you think doctors have practiced so much on dead animals and what not during their studies? According to you, they could have gotten a firm grasp of things through reading alone.
 
  • #15
brewnog said:
Fred, you're an industry professional. Have you personally ever built a gas turbine engine from scratch, from bits of raw metal to a finished running product?!
I guess technically we do that every day :tongue2:

In college, my senior project was the closest I got when we took a turbo charger and put a can external burner on it and outfitted it with a heat exchanger (recouperator). We did efficiency calcs with and without the heat exchanger. We did no machining for the rotating group and we were doing this under the supervision of a small business that makes very small turbine engines. It was a great experience, but I did learn a ton of stuff from those guys. I shudder to think of all the things that can go wrong when I see/hear of people do this with no guidance the first time out.

Admittedly, I now think about trying my own from scratch. I am pretty leery of doing it just because to really do it from scratch means a ton of developing my own hardware. Plus, it's not like I can walk into our foundry and pour my own engine case or have a 5 axis machine up my compressor rotors...It would be the same as you wanting to develop your own engine from scratch. I bet you have thought about it!
 
  • #16
LovePhysics said:
I doubt it. Read all you want about something as simple as welding. After a year of reading about all the techniques, you still will not be able to weld better than someone who has practiced for two weeks.

Why do you think doctors have practiced so much on dead animals and what not during their studies? According to you, they could have gotten a firm grasp of things through reading alone.
I agree with Brews. I guess it all depends on what you mean by "getting a grasp."

There are tons of references out there that will go into every detail of design, maintenance and cycle calculations you could ever want. The things you can't get without some pretty in depth knowledge are things like effects of compressor blade design and so forth.

Welding is not a good example to compare. Welding is, in comparison, a safe and relatively simple endeavor. To get good is an art form. It takes a ton of practice. The same with your doctor analogy. The point being is that we just want to make sure that you understand that, despite videos of people strapping them on go-karts and such, you are talking about a very unsafe project. It is compounded by your entry level knowledge and lack of experience. The people you see running engines in their garages and on mini bikes are fools and it will only take one failure to change their minds.

Just be careful and remember this before you hit that igniter button every time: It is NEVER the details that you accounted for that will come back and bite you in the butt. If you get bit, it will be by something you never thought of.
 
  • #17
I agree wholeheartedly, the knowledge and experience you gain from actually "building" something from the ground up far exceeds that from reading or learning about it. Conceptually, you can do just fine with books or talking to someone but that only gets you so far. I have seen many A students go through an engineering program but do not know the first thing about practicality... You will never fully understand something unless you actually do it.

Also, you guys are making this sound as if he wants to build a nuclear power plant with a risk of being exposed to radiation. This is a gas turbine. Yes, it is a bit dangerous - but only locally. Nothing that can't be solved from moving away a couple of feet or meters (whichever you prefer) or shielding it.

The real question at hand is... are these dangerous? The answer is yes and no. Yes, they are dangerous if your a grease monkey that slaps things together and goes to town. and No, if you are a intellegent person/engineer they are not dangerous. Because an intellegent person/engineer should always think about every aspect of the project, including not only the design, but manufacturability, cost, and safety. That is what they were hopefully trained for.

chris
 
  • #18
You're right. I don't know what I am talking about.
 
  • #19
My comment about Fred singlehandedly building a jet engine from scratch was tongue-in-cheek, it's absurd to think that this would be the best way to gain expert knowledge on gas turbines. You'd learn a load about prototyping, but very little about gas turbines. Analogies to welding and surgery are ill-conceived; if you want to learn to machine jet engine components then do so, but it won't tell you a thing about their performance. Learning to weld a car chassis won't make you an expert in vehicle dynamics.

There's a reason why Rolls Royce, GE and Pratt & Whitney have multi-million dollar R&D budgets. It's not just so that they can get a slight market advantage over each other, it's because even doing the most basic development work on even the most basic of these products is a huge task, requiring huge amounts of resources and huge amounts of expertise.

If it was so easy for some guy with an engineering degree, a basic knowledge of turbomachinery and some workshop skills to build a working jet engine from scratch then they wouldn't bother so much.
 
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  • #20
FredGarvin said:
You're right. I don't know what I am talking about.
:rolleyes:

C'mon guys, one of the things that is so great about this forum is that we have true experts in here. Listen to them!

Those of you who are saying you can't understand how a jet engine works without building them are just completely missing what it means to understand how something works. No jet engine that you could cobble together with pare parts is going to be an accurate representation of a "real" jet engine, so it will tell you virtually nothing about how a jet engine works, much less what it actually takes to design/build a real one.

To learn about efficiency, you read the efficiency equation and description in a thermodynamics book. Building your own poorly-designed (to put it generously) jet engine and plugging bad data into the equation isn't going to improve your understanding of how the equation works.
 
  • #21
brewnog said:
You'd learn a load about prototyping, but very little about gas turbines. Analogies to welding and surgery are ill-conceived; if you want to learn to machine jet engine components then do so, but it won't tell you a thing about their performance. Learning to weld a car chassis won't make you an expert in vehicle dynamics.
Yes! Learning to weld or perform surgery is much more about practicing hand-eye coordination and how to operate certain pieces of equiment/tools than it is about learning the chemical properties of metal (no, welding is not just melting two pieces of metal together...) or the operation of the human body. Same concept here.
 
  • #22
clmohn said:
I agree wholeheartedly, the knowledge and experience you gain from actually "building" something from the ground up far exceeds that from reading or learning about it.
Sure, but that's only because it will take you 20 years to design and build a decent jet engine on your own! (and then only if you are really, really good)
 
  • #23
This discussion is becoming really ridiculous. Do you want to bet who a 'jet company' will hire if there are two people from the same university and degree, but one has made gas turbines and the other hasn't? (and why) Not that getting accepted anywhere matters to me, I just want to acquire knowledge about something and the skills required to make it.

If you're not into aerospace, or if you don't want to ever make a jet engine, then don't. No one is forcing you. If you think that reading will teach you everything, then by all means keep reading until you forget how to walk.
 
  • #24
When I was in Junior High, I had a year-long "gifted" program project where I designed and built a functional wind tunnel and did some rudimentary tests in it. I don't think it ever came up in a college application.

If you approached Fred's company and told them this story, I suspect their reaction would be "aww, how cute - where's your transcript?"

If you want to design a jet engine as a hobby, by all means do so and have fun (just don't get killed), but thinking that you will actually get a leg-up either academically or professionally because of it is quite simply wrong. It is an incorrect approach to learning.
 
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  • #25
russ_watters said:
If you want to design a jet engine as a hobby, by all means do so and have fun (just don't get killed), but thinking that you will actually get a leg-up either academically or professionally because of it is quite simply wrong. It is an incorrect approach to learning.


I would disagree with this. It shows that the OP has a higher interest than others. Maybe there won't be a darn thing learned from the experience of building one but it shows that there was enough initiative to go ahead with the project. I've hired, trained and recommended various types of people and those who have the desire to 'tinker' on their own always turn out to be the best employees. I'm not going to say that it trumps everything else, but my point still stands.
-
As for the technincal aspects of building a gas turbine? I wish I had the real world experience in order to give you some really good advice. From what I've read about the do-it-yourself turbines, designing a good burner can is the key.
-
Here is an interesting link: http://www.rcdon.com/html/gr-5_turboshaft_engine_project.html
-
Naturally this engine was not built from the ground up, but I think it is pretty impressive that he was able to build the power turbine from the ground up.
 
  • #26
Have a look at the following link: http://www.gas-turbines.com/nt3/index.html
-
Now I cannot say I've verified it, but apparently the Air Force found it to be a worthwhile project to use a turbocharger for a jet engine as mentioned in the above link.
 
  • #27
The Air Force looked at them for a low cost option for target drones. They are always doing that. It comes in cycles. They will try pretty much anything to see if a route is viable. We have done some low cost engine projects in our day and they are relatively simple and small. Using a turbo that is off the shelf makes perfect sense. They would NEVER use it in that configuration, but for investigative purposes it fit the bill nicely. I don't think anyone debates the use of a turbo charger as a base for a home made engine.
 
  • #28
Hey,
nice to find out other people who love gas turbine engines. I'm one of those...:D First of all, if you want to build one, you have to learn not only the basic concept but so much more. It's not easy to build a turbojet (and here I'm talking from experience). Although the basic concept of a gas turbine, is simpler than that of a piston engine, it takes much more to build a gas turbine. Next, when reading something about gas turbines make sure it's approved information for now since sometimes on the internet there might be some false ideas. Not the first time that I had to intervene to correct other people.
You might also like the idea to join a local aviation museum. It's indispensable if you want to build a gas turbine because it's the only place where non-certified people are allowed to work on the real thing since usually those engines are for display purposes and some small mistakes are more tollerated. I am a member of the Malta Aviation Museum foundation and although I have been a great fan of gas turbine engines since I managed to grab their concept, I begun working on one only a year ago and that was only on an already dissasembled Napier Gazelle: A Dual-Shaft Turboshaft engine. If you happen to be on a vacation here in Malta, please do consider paying a visit to the aviation museum since everyone there is always willing to help.
Back to your ambition: Please consider safety as your primary aim. Never risk your own health in the hope that something works. I know what I'm saying since despite my experience and my considerable number of attempts, I never got an engine to work and if something blew up, there would be no chance of getting an engine built, would it? Also, If you're building a gas tubine, don't get your hopes high. Don't say "I think it will work like that", make sure it's a proven concept or at least get to prove it yourself. Don't be afraid to be inventive, who knows maybe someday, you might get to patent your own parts for a cheap gas turbine engine. By the way, do spend some hours everyday looking at different diagrams perhaps some better ideas might dawn on you.
Keep also in mind that disappointment can be viewed from a lot of perspectives. I usually see it as a way how to make a better engine the next time...just do some self-criticism.
Good luck with everything
Kyle.
P.S. If you want to contact me please do not hesitate to contact me by PM
 
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1. How does a gas turbine engine work?

A gas turbine engine works by taking in air through an inlet, compressing it, and then mixing it with fuel and igniting it. The hot, expanding gases then pass through a series of turbine blades, causing them to rotate and produce power. This power is used to turn the compressor and the engine's fan, which draws in more air to continue the process.

2. What materials are used to make a gas turbine engine?

Gas turbine engines are typically made of high-strength and heat-resistant materials such as titanium, nickel-based alloys, and ceramic composites. These materials can withstand the high temperatures and stresses generated by the engine's operation.

3. How is the efficiency of a gas turbine engine measured?

The efficiency of a gas turbine engine is measured by its specific fuel consumption (SFC), which is the amount of fuel needed to produce a unit of thrust. Other measures of efficiency include the engine's thrust-to-weight ratio and its specific thrust, which is the amount of thrust produced per unit of airflow.

4. What are the main components of a gas turbine engine?

The main components of a gas turbine engine include the compressor, combustor, turbine, and exhaust. The compressor is responsible for pressurizing the incoming air, the combustor mixes and ignites the fuel to create hot gases, the turbine extracts energy from the hot gases to power the compressor and fan, and the exhaust expels the gases out of the engine.

5. What is the maintenance process for a gas turbine engine?

The maintenance process for a gas turbine engine involves regular inspections, cleaning, and replacement of worn or damaged parts. This ensures that the engine continues to operate efficiently and safely. Maintenance also includes monitoring the engine's performance and making any necessary adjustments to maintain its optimal functioning.

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