Resources!

[Mourita]

Hi guys!

Well.. first may i introduce myself? :D

My name is Ricardo, i'm from Portugal, i guess this is the first attempt to build an home made jet engine here @ my country.. last year a friend and I thought about this 'impossible' project.. of building a miniature turbine..!

We thought it was impossible until i found out a turbine group at yahoo.. Since then i've been 'studying' and trying to find a way to make a jet.. the less expensive way..!

Buying a turbo here is quite expensive.. it can go from 400 € to 1000 € .. that's a lot.! :| So.. i started thinking.. "why not only use the compressor/turbine wheels and make the entire housing by myself?" well... that's when i found out this group.. ( a few days ago... ) sorry for this small 'briefing' about me.. i thoght you guys just wanted to know what moved me to go forward on this project.. too much Discovery Channel i guess... maybe i'll break a speed record who knows! :P

Well.. i just need help to get things started.. i want to make a big size RC jet plane... but i don't know where to get resources and stuff.. i heard about books, plans... calculations and lot's of headaches..! but i just don't know where to start from.. which tools do i need.. etc..!

I hope somehow, that you can explain where to get these resources so i can make my own turbines.. ( 4 in total... ).

Well.. Thanks anyway.. oh.. and sorry for my english... I usually don't talk much 'cause i'm Portuguese... :P

Regards,

Ricardo.

[jcow]

hi ricardo,

I have bought a small compressor wheel (4.9cm exducer) from US ebay,with the intention of building a small gas turbine. It cost me $26 including postage to the UK which is not bad. I recommend looking on ebay, as there are usually turbocharger components that can be posted worldwide from the US.

I also realised that buying a whole turbocharger is very expensive considering that I only want one part out of it, and there are virtually no turbo components for sale on UK sites.

The compressor wheel took just over a week to arrive in the UK and was in very good used condition and balanced.


BTW, making a gas turbine using a turbocharger radial turbine is apparently extremely difficult, so you will need to make an axial turbine. Apart from standard workshop tools, you will need a decent lathe with at least 12'' between centres, MIG welding equipment and precision measuring equipment.

[mcjustis]

Ricardo,
here's my thread about building mine.


http://www.rcgroups.com/forums/showthread.php?t=391515

[Mourita]

jcow

Thanks , well.. pardon my ignorance, but.. when you mean a lathe do you mean something like this -> http://en.wikipedia.org/wiki/Image:Conventional-lathe.jpg <- well.. i don't have much tools..! I'm looking for a book called Home Built jet engines from Trapplet ( i don't know the writters name ), i've ordered it already but they don't seem to answer my emails.. I'm hoping that it has explained the tools i've got to use.. Are those equipment expensive?

Maybe i could find someone who could help me out with that...

Thanks for the tip, jcow.! :D I'll keep posting as soon as i get the book and the exducer..!

mcjustis

Well, i've seen your thread before..! many times :P the problem is that i can't understand some terms you use.. ( language problems ) like the 'lathe' thing on this post... i had to go to wikipedia to find out what that was..! :P But since i'm a fast learner i guess i won't have many problems understanding it.. I'm a complete newbie on this.. all i know is the jet engine theory...! Well.. wish me luck..! and thanks :)

I'm going to bid some exducer now..! I hope you guys can help me through this project..! I've got this innovative idea... let's see if i can get it working.! :)

Many thanks and regards, RM.

[Mourita]

http://cgi.ebay.com/ebaymotors/Mitsubishi-3000GT-Dodge-Stealth-Turbo-Compressor-Wheel_W0QQitemZ160030162806QQihZ006QQcategoryZ3374 2QQrdZ1QQcmdZViewItem

well.. i've just bidded this one..! I hope it was a good choice..! it seems preety nice..!

[jcow]

mourita,

funny you should say that! Thats exactly the same turbo compressor wheel as mine! It is quite small, but you could design a small engine around it, like i'm doing.

Yes, the lathe in the picture is a model engineer's lathe. A good size to use for building a small gas turbine, however they are quite expensive at £250+. I bought mine off ebay for £150, it is an old RandA type B lathe, http://www.lathes.co.uk/randa/index.html

A good book to get is 'Gas turbine engines for model aircraft' by Kurt schreckling (traplet). This is extremely useful, with details on designing gas turbines and building instructions for schreckling's FD3/64 engine.

I have no idea how much metalworking lathes are in portugal but i guess you can get a good one for under €350. this is the most expensive tool you will need.

hope this helps, jcow

[mcjustis]

This is a lathe, actually this is what I used on my turbine. This lathe is in my garage.
Martin

http://www.medfordtools.com/Jet%20Metal%20Working-2.html

[Mourita]

Jcow,

Well.. i already bought a book called "Home Built jet engines" it's also from traplet publications.. It says it has lot's of details on building small jet engines.. since i bought it last week, i'll wait for it, it takes about 10 - 14 days to arrive home.. and if i think it isn't enough.. well.. i'll buy the other you recommended..! :D

I've bidded a 2.500'' exducer compressor wheel before but i've quitted since the shipping price was almost the same as the compressor wheel..

I think that compressor wheel will become handy..! ( if i win it.. 4 hours remaining :D )

Thanks again! :)

mcjustis,

Hum... 3000 $... that's kind of expensive..! :) I think that a friend of mine might have one of those.. he's a mechanic and he has lot's of stuff like that ( TIG welder, lathe.. etc.. ) i've got some craftsman tools ( i think that's how they're called.. ), like wrenches and things like that.. what i'm more worried about is the lathe itslelf and the tig welder... but i'll find a way..! i allways do ;)

Thanks anyway guys..!

I'll keep posting my progress..! ;)

Later i will tell what is my idea :) I just want to run a small jet first to see how hard it is to do this :) I've allways been curious about this eheh

Regards,

Ricardo Mourita

[mcjustis]

That lathe may seem expensive, but it's not. As for the hand tools, you won't need a whole lot of those. As far as running them, they're very simple to run, the trouble is in getting them to run reliably. I can tell you that you probably won't be too successful on your first try. Don't get discouraged just keep trying until it works.
Later...
Martin

[Mourita]

I can tell you that you probably won't be too successful on your first try. Don't get discouraged just keep trying until it works.

Lol... i won't get discouraged... :D i know i will probabbly fail the first time.. but that won't be a problem.. i've never been an easy quitter ;) eheh..

Thanks for the support guys..! :D

When i get things running.. i will post some pics..! :)

Regards,

Ricardo Mourita.

[Mourita]

Hi again guys..!

Well.. finnaly i've got "The Book"! It teaches how to make 3 different turbines, a KJ-66 TK-50 and another one.. i haven't read the book yet just saw some parts including diagrams, a bit of theory, etc... well.. there's one problem.. What's the difference between a TIG / MAG / MIG welder ? Well.. they all have veryyyyyyyy different prices it can go from $150 to $1.500... What can you guys advice me ?

There are also some terms i don't understand.. and strange measurement units... isn't there any glossary for these terms and units? What is a Kpa ? :| like this for example.. Well.. ok.. i had good rates at physics.. but.. lol.. i'm not an Einstein :D I hope you can help me on this..! :) Like i said before.. i knew i would have problems with tech. terms in english.. :)

Regards,

Ricardo Mourita.

[mcjustis]

Tig would be what you would want to use. They use a "torch" in one hand with a foot pedal controlling amps to it. If needed you use rod of the same material you are welding to 'melt' in a pool of molten metal. You can also fuse the parts together, which is just melting the two pieces together. Although they are expensive, you have much more control over the weld quality. I wouldn't use a mig welder unless you absolutely have to. With a tig, you can weld very thin sheet metal like a turbine case. Tig welding requires much more skill, you could do a search and really see what each is good for. If you have the money go for a tig. Mig welders use a wire feed through the handle which melts when it comes in contact with the grounded metal. They are usually (at least for me) used for heavy welding and fabricating although I'm sure someone out there uses theirs for delicate work. I have seen guys weld gum wrappers together with a tig welder.
For the conversion factors you can use any conversion programs. here is one..

http://www.convert-me.com/en/

A kPa is a kilopascal. Equal to 1000 pascals and it's a unit of pressure in the metric system. One pascal is equal to one newton per square meter. It's a very small value so usually you will see it in terms of kPa. Here in the US we usually use psi or pounds per square inch.
Just do a search of engineering terms and you'll find more than you ever care to know.
Also if it helps just convert everything to units you understand. Inches to millimeters, pounds(force) to newtons, psi to kPa, etc...
I'd do the KJ-66 if I were you. MAny out there and you can easily get parts if needed.
Later...
Martin

[Mourita]

Hi there,

Thanks for the tip..! :) Well, i've finnaly received my compressor wheel, i guess it's time to start working.. the combustion chamber seems less complicated to do.. so i'll start with it, since i've got all the 'hole' diagrams, i'll start with the KJ-66 wich seems to be the most powerfull model turbine too..

Well, i'll go for the MIG welder, it's cheaper, my mother works at this store ( it sells constrution items, all sorts of machines, alluminium, screws, nuts, etc.. ( i don't know how you guys name it in english ).. i don't have much cash to spend, probablly i'll have to go to a junkyard to get some parts..!

Well.. i also have serious doubts on how to make certain parts ( the small ones.. ) but.. like i usually say... on step at a time! :) first.. combustion chamber.. then.. i'll go to the rest :) I'll need a welder later when i start joining things up, time to spare some euros :D ...

Once again, thanks for the tips .!

I see loooooot's of work coming my way.. but... i like the idea ! ;)

Regards,
Ricardo

[mcjustis]

Ricardo,

Quick question, you say you already have your compressor wheel? What size is it? If you plan on making a KJ 66 I hope you bought a compressor in the 66mm diameter range. Just a thought.
Later,
Martin

[Mourita]

Ok... now you've got me :O !

Well.. i've bought my compressor wheel and it has about 4,9 - 5 cm .. yesterday i was reading the book also, and i thought about that.. i was wandering.. can i scale down the kj66 so that the compressor wheel is suitable? ( lot's of calculations are needed.. i hope.. or else that wheel is useless ) .

Anyway i thought it was the turbine wheel that had to have 66mm ... i've got to read this book more carefully..!

I've placed the comrpessor wheel at the diagram ( on the book ) and the scaling is 1:1 ... that's why i didn't think too much about it's size..

Oh.. and good news.. i've found someone who can make me some parts with his lathe and the same guy has also a MIG welder..! I guess i've got a bit of luck! :D 2 in 1 ;)

This weekend i'm going to start to drill some holes at the sheet to make the combustion chamber..! Wish me good luck! :D

By the way.. what do you mean by 'precision measurement tools' ? are those something like this:

http://buy.overstock.com/images/products/L955730.jpg

and

http://www.jayindustries.com/images/school_compass443.gif ?

That's a question i've wanted to ask for a while.. but i couldn't remember before :) Sorry about the dumb question.. but.. it's the so called 'terms' again..

Regards,
Ricardo Mourita

[Mourita]

Well... new plans.. we're goin' to the TK50 turbine.. The compressor wheel has less 1 0,1 mm than the required... big question... will this be a problem ? ( balancing ? )

Regards,

RM.

[jcow]

Mourita, That is the kind of measuring equipment you'll need. all the components of the turbine need to be fabricated to the highest precision possible. That set looks quite good and contains the stuff you'll need.

mcjustis, while im here could i please ask a quick question?
I am using silver steel (1% carbon) to make the central shaft of my turbine. Is it neccesary to harden the shaft after machining? I am worried that heating it using a propane torch will form a oxidation crust or warp the workpiece. Thanks

[mcjustis]

Jcow,
You don't need to heat treat the shaft. If you did, you'd most likely bend it. I used 4140 steel for mine and had no problems machining or polishing it. To date I've had no problems with the shaft (built this turbine 4 years ago). Do you have one under construction? If so, I'd really love to see some pics.
Later...
Martin

[jcow]

Jcow,
You don't need to heat treat the shaft. If you did, you'd most likely bend it. I used 4140 steel for mine and had no problems machining or polishing it. To date I've had no problems with the shaft (built this turbine 4 years ago). Do you have one under construction? If so, I'd really love to see some pics.
Later...
Martin

Thanks Martin,
I am going to start building the diffuser system and shaft tunnel for my turbine soon. I'll post some pictures when i have made some progress.

[mcjustis]

Looking forward to some pics. Oh yeah, I forgot to mention, if you can find it use stress relieved 4140 for the shaft.
Martin

[Ravill]

Hat's off to you gentlemen. You are building turbines that you'd trust in a multithousand dollar airplane? Hat's off you sirs!

Raf

[mcjustis]

Ravill,

Actually the plane I'm putting my turbine in is the RCM Eagle V. I paid $27.00 for the plans, the wood was given to me, I'll have probably $200 in servos, making my own retracts, wheels, and brakes (maybe $20 for the aluminum), so with a little patience and hard work, I'll be flying a multihundred dollar airplane. I'd probably have more $$ in a 1/4 scale plane.
Martin

[Ravill]

Wow. Thats impressive. Good job. I'm jealous and can't wait to see the finished product.

Raf

[Mavericksa]

Well... new plans.. we're goin' to the TK50 turbine.. The compressor wheel has less 1 0,1 mm than the required... big question... will this be a problem ? ( balancing ? )

Regards,

RM.
Mourita, Im from South Africa and followed this thread of building your own turbine. Im am very interested in rc jets and turbines. what is the name of "the book" that you are using and where can i order it from??
THANK YOU