Was just wondering if anyones knows if the cheap $150 turbos are ok for building a jet engine, some say they are good for cars, and sone differ, not sure about for turbocharger jet engine application, hoping so because im on a budget but really want to build an engine.
Post by adamrenwald on Aug 12, 2022 9:53:32 GMT -5
Ok thanks, i actualy found more info about this on page 7 of this thread about turbocharger jet engines. I guess im going to use one untill i can get more income comming in and than will upgrade and just keep the coumbustion chamber so i can swap everything over, ive done so muxh research here on all the threads and there are so many questions that have been answered by people asking the same exact questions i had tha i cant find anywhere else online, this forum is awsome, now i feel super smart and that i can build a good engine now, i built my first turbo charger engine after about 17 yrs of wanting to buold one and comming from being interested in valveless pulse jets, always thought it was way harder to build a turbo jet but here we are and now im confident enough, i built my first turbojet engine and it failed after the 3rd throttle up, replaced the turbibe and expected it to happen again and sure enough in the same amount of time it did it again, turbine shroud glowed red, i eye balled the 30 20 50 flametube design, now i will use jetspecs for this build im gonna do, also learned here its better to have a bigger turbine than compresure which i didnt know in the previous build, i think that engine had the same size comp/turbine. So now that im worried about spending money on a turbo only to have it shredd and melt off the blades, i do feel nore confindent that with a proper flame tube that i wont have to worry that. I was wondering if after the length of the flame tube where i need to add the funnel down section to the turbine shroud was wondering if i made it a little longer so the gas can cool off more befire hitting the turbine, reading through the posts i seen a few guys mention about it but not to depth in the info, all i got was some guy saying dont do it because the pressure drops and less power, but for the cheap amazon turbos im wondering if that is better for a longer lasting engine
The temperature going into the turbine stage is highly dependant on the backpressure put on the engine by any jet nozzle or freepower turbine wheel restriction downstream , having an overlength flametube won't help , Jetspecs has already built in "generosity" of size .
If you fire up your engine without any "backpressure" it should produce its lowest temperatures , if they do produce low temps then we can SLOWLY start to add some backpressure to increase temps as well as thrust, gradually working up to what we want, taking safety into account.
If your basic turbo has that 20% extra outlet area over inlet area to the wheels with the turb scroll having a largish A/R , and your combustor is built to Jetspecs with reasonable attention paid to fuel delivery/atomisation , and without any downstream restriction , the engine should work , a lot of damage can be done trying to get the engine started if the starter isn't up to power , so we need to be very careful about temperatures during spoolup
Before purchasing a turbo , post a Link so we can check it out and give a thumbs up , .....or down :-)
Just some food for thought. I built an engine that actually had a larger compressor inducer than turbine exducer (because that's just what I had laying around) using the jetspecs formula and against the odds, the engine runs very very well.(although makes no real power)
The turbo was a Peugeot Citroen Ford 1.6 Hdi Turbo 49173-07502 TD025
If you aren't planning on doing anything crazy, I think you don't have to be too fussy.
Last Edit: Aug 21, 2022 15:32:05 GMT -5 by noshell
Havent figured out how to post videos on here yet, only pics but im almost done with engine, the hardest part was trying to find the outer combustion chamber tube which needs to be 7" diameter, i found out that the soda acid fire extiguishers are 7" so found one on craigslist and gonna pick it up tomarrow and get to work, just got the combustion chamber and the funnel down piece from the flame tube to the 4 bolt bracket that bolts down to the turbine inlet shroud and than connecting pipe from compresser to the chamber and done, will post a link if i cant post the video on here.
One other thing I found that made starting MUCH easier on my first engine was widening the spark plug gap. It literally wouldn't start with the gap at a "normal" amount, it was sparking but just wouldn't go. I opened it up and she fired up straight away.
Yea i did that before i welded the spark plug to the flame tube, for this particular spark plug i was only able to open it just a little more other wise it would spark to the side, i should have used a different plug that has the skinny electrode in the middle vs the fat one, than id be able to open it up a little more but i think its work, what you using for ignition? Im using a hand held push button igniter like on a bbq grill, so i kinda need someone else to help me start it because i will need to click it a bunch of times before it will ignite, i did buy a cheap amazon spark ignitor and when i used it it only worked for 5 mins and than broke, so im not sure if i got a defective one but i dont trust it so will not buy another one, i thought of usin a stun gun but dont wanna shock the crap outa me in accident.
I'm using a bbq ignitor currently, but it's not a brilliant spark.
The best source of spark I have used is to run a small engine (leaf blower/mower/trimmer) and run the HT lead from that to the spark plug on the jet engine, then the earth from the jet to the spark plug of the small engine.... Basically just get a small engine to spark your engine aswell as itself.
Big fat blue sparks at 2000rpm or whatever they idle at. Careful though as you get one hell of a bolt
Good idea, how ever for me i always like the idea of less stuff, like i see peoppe who build engines with oil pressure gauge, compressor gauge, a huge platform of instrumentation, which i like that kijda stuff to because you can keep track of everything and its more stuff to build which is fun but im also very simplr and like the least amount of stuff as well, almost as if i wanted to build it for flying in the air, however i know a turbo charger is allready super heavy for the amount of thrust, but i want the least amount of stuff to run it, ive seen some people start with just an open flame in the back of the turbine which id much rather like there for i could take the spark plug out as well and have another less thing on it. I guess the desighn and size might make the difference thow wheather or not a open flame out the back will get the fire to suck up into the flame tube because on my last turbojet engine i built, i tryed for over an hour to start it with open flame and it just wouldnt suck back inside, i tried all diffeerent methods playing around with the propane valve and air, it was a tiny turbo, i seen a guy on youtube successfully do it thow, maybe it works better on the biggers ones