CrackerboxSydney

Hi all,
I'm thinking of building one of these jet engines:
http://www.marchlabs.com/kj66_jet_engine_s/29.htm
The idea is that you buy the compressor wheel, and get the plans which you take to a local CNC shop to make the rest (apparently the compressor wheel requires specialist equipment to make that most shops wouldn't have). Also you use a toyota oil filter for the outer casing and combustion chamber.
Sounds to me like a cheap way to get into rc turbine jets.
Has anybody tried building the jet from this company?
I'm a bit suspicious because i can't find any reviews online, all i can find is a bunch of spammy sites with the same word-for-word article talking about building a march labs jet.
Thanks a lot

Randy M.

My Feedback: (38)

This has been on here many times. Do not waste your money. If you want a kit, buy wren. Buy cheap- buy twice. Or in this case, many...

CrackerboxSydney

Thanks for the heads up! I'll have a search here and see what turns up.

CrackerboxSydney

Umm... am i missing something? You say it has been discussed many times here before, but i can't find any mentions of march labs jets here other than this thread:

http://www.google.com.au/search?hl=e...=&oq=&gs_rfai=

However, i'd like to hear more about 'wren' that you mentioned...

Randy M.

My Feedback: (38)

http://wrenturbines.co.uk/usa/

Kelly W

My Feedback: (2)

Hey Cracker,

Do a search for KJ-66, home built turbine, etc. Lots of people have tried this. Please trust me when I say its not as easy as it sounds, nor is it likely to be cheaper in the end vs. buying a kit engine or an entry level production engine new or used. Making the parts is one thing, getting the tolerance stack up between the parts to work out is another (with thermal expansion), getting the balance true to 3mg-cm or less is another (after you make a balancing rig, which is a project on its own), and just getting the engine to run properly overall is another, etc...

Kelly

Jgwright

Have a look at this video if you need need some convincing that this is a bad idea. The engine appears to be a JetJoe 1800 and the guy is giving a great demonstration of his lack of knowledge of turbines and shows how not to start a turbine. The title says it all, MICRO TURBINE JET ENGINE BEING BROKEN IN!

http://www.youtube.com/watch?v=mTXBC3peZU0

John

LGM Graphix

My Feedback: (22)

A toyota oil filter for a combustion chamber, and you're really asking if this would make a good turbine? I'll echo what the others have said, buy a wren kit if you really want to assemble a turbine yourself, but you really can't build one and buy electronics for any less than what some of the new turbines on the market cost.

Gordon Mc

My Feedback: (11)

I recall some of the very first RC turbines being built inside a cannister from something like a Coleman gas can (FD3 IIRC), and others (Kamps / Schreckling ?) having compressors made out of plywood.

However, there's a VERY big difference between the pioneers in our hobby using such materials for figuring out how to make a turbine, and a "regular user" simply trying to save money and expecting to get a quality running product out of it.

Gordon

LGM Graphix

My Feedback: (22)

Yup, I remember that stuff too Gordon, but being innovative and looking for a "cheap way to get into RC jets" are 2 different things as you say. Those first turbines didn't produce much thrust. I think that's the one of the biggest problems in turbine modeling these days is so many are looking for the "cheap" way into the hobby, there's no such thing as cheap, cheap almost always ends up being expensive.

basimpsn

My Feedback: (5)

OMG thats so painful to watch

edgeflyer

My Feedback: (15)

I actually am building a KJ 66 myself. I don't want to go arround badmouthing Marchlabs, but Jeremy March himself is just learning these motors. My experience so far is that yes you can save money and yes its much harder that it is made out to be. If you don't have good machining equiptment its gonna be somewhat tough. That being said, The wren kit would be great but i think its still more than building a KJ. Also in order to fly a homebuilt turbine on an AMA sanctioned field it must be certified and to do that you will need a material list from the manufacturer of the turbine, and compresser wheel along with some other data. Then you must actually run the motor for someone who does turbine wavers to be certified. It is a fun process, and you can build a good engine with manufactured parts for arround $1,400 dollars. My recomendation is to buy the kit from www.JMPrecision.co.uk They make everything you think you can do yourself (but actually can't) except the outer case. Trust me when I say buy this kit. On ebay there is a KJ66 seller by the name of weleyland. His stuff is very good and has the waver certification for the compressor assembly, but his parts require some altering to work together, but he builds outer cases, you just need to tell him you need a 125mm long case instead of his stock case as the JMPrecision front cover needs the longer case. DONT USE THE TOYOTA FILTER. you save twenty dollars and there's stories of them cracking at the NGV. Also welleylands cases make that 1400 dollar investment look like a nice piece not a piece of junk. I also heard the toyota oil filter causes the engine to run out of control. HA HA. For the FADEC you need to order one that is for the KJ66 from Xicoy they haVe them CHEAP and its the same unit wren uses. I say go for it. If you want the satisfaction of building it yourself go with JMprecision, if you want the tried and true bolt it together in a night get the wren kit. I have a lot of knowledge right now on the subject and kmow where to get what so do hesitate to PM me if you need.

edgeflyer

My Feedback: (15)

also remember there are several variations of the KJ 66 so parts from one supplier won't nessasarily work with parts from another. example : The first inlet bell I purchased through JMP was the wrong radius for the compressor wheel through weleyland. also I had to have the longer outer case made to fit JMP's from cover design. This is why I said to but JMP's kit. Also have patience if you order from JMP it takes several weeks to get stuff, but its the best way to go that I know of right now.

blighty

just to throw in another option,

i finished a plan built MW54 last year. you buy the plans and a few odds and sods, like compressor, wheel, ngv, bearings and anything else you cant be a***d to make. and you end up with this.

blighty

............. and after a few hints and tips from Wren, they go like this.

[youtube]http://www.youtube.com/watch?v=4Pjt-WCSEwU&feature=player_embedded[/youtube]

lov2flyrc

My Feedback: (24)

Or....If you just want an inexpensive engine, you can buy one of [link=http://dreamworksrc.com/catalog/product_info.php?products_id=243]THESE[/link] and have an outstanding running engine out of the box with no assembly required!

CrackerboxSydney

Blighty - that's what i'm after! Someone who's built one as much as possible from scratch, and buying the rest of the bits they couldn't make.
Guys, i'm not hoping for this to be as slick or reliable or powerful as a bought one! The hobby for me is building the engine, not flying the plane!
Blighty, do you have a build thread or something?
Alternatively, i'm thinking of making a pulsejet for the sake of simplicity/affordability. Anyone made one of those ?

blighty

hi cracker,

i did a little build thread over on cnczone.com under the turbine section, but it was just some pics posted every now and then. i'm thinking about building another one and filming every part i make, speeding it up and putting it on YT.

depending on what you want to do with the turbine tels you what you need to buy. take the NGV. you can make it out of .5mm SS and spot/tig it all together, but if you run the turbine for more than a minute or so it will warp and you'll have to make another one. i intend to fly mine so i went with the cast NGV. you will have to buy the turbine wheel, compressor fan and the bearings. you can make the preload spring, but at £3 from Wren its not worth it. like the front and rear nut, they both have a left hand 6mm thread. the tap to do this was £36, but again you can get both from wren for 12 odd quid.

i also got a combustion chamber from wren for the same reason. the inconel tube was £40, to make a spot welder out of a microwave £50 and material for the tooling to make the end caps £20. they sold me a C/C for £120. since then i have found out how to make a spot welder for free. if i knew that then i would of made it my self.

do you have lathes and mills??


pulse jet,

try this place. http://www.airtoi.com/pulse.htm i have one that a fellow forum member set me to see if i could fix. if you want a nice and easy pulse jet to build look up Japanese valveless pulse jets.

Randy M.

My Feedback: (38)

http://www.rcuniverse.com/forum/m_80..._1/key_/tm.htm
Probably have better luck with this if you have the capabilities.

blighty

i like that one, its like a KJ66/wren demon child.

CrackerboxSydney

No, i don't have a lathe or a mill, i would most likely be buying a plan and taking it to a CNC shop to get it built.
Maybe a pulsejet is a better idea. I can't find any good small valveless pulsejet designs, all i seem to be able to find is that really big lockwood design that everyone has their own customisation of. Anyone recommend a good small valveless design?

Randy M.

My Feedback: (38)

I bought the UT-160 disc. It has all the plans and cnc code on it. A good machine shop should be able to run with it. I have mine here somewhere and my machinist (cousin-in-law) copied it to his computer. If I get the itch I'll give it a shot.

Felix Barrao

woww, after seen this video, I would never buy something to this guy..

blighty

just had a quick look on the net and found this............. http://www.beck-technologies.com/freeplans.html
you may want to have a proper read (unlike me) of the whole web site and go from there.


so you going to buy plans and give them to a cnc shop to build? that i think could cost a small fortune. if you want to go that way then maybe this would be a better option http://wrenturbines.co.uk/engines/tu...ren70/packages and buy the kit and assemble it your self, or any other jet manufacturer that does there turbines in kit form.

AdriFlyBoy

Just one question.5 years ago there was Wren 70 kit for 1500$ from jethangar.com.Now,it is 2000$.Why is that so or there is still 1500$ wren kit around?