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Post by areacombustor51 on Jan 29, 2014 8:33:56 GMT -5
Well since it's so cold here in Indiana I've put my turbine in hold until spring. I was wondering about I new way to start my jet. I can't seem to get the propellors to spool fast enough to begin to build and idle the jet. I saw on YouTube wish I had the link it was in Chinese. Anyway it had a huge amount of air released and the turbine spoked up and was set to idle in about two seconds. Could I use for say a 20 gallon air tank and weld a idk 1-2" fitting on to my combustion camber. I was thinking a 2" ball valve and a full tank of compressed air say 100psi. Would this work as a starter generator. One more question I haven't found an ignitor for my combustion camber. I've been igniting the jet with a propane torch right at the end of the exhaust housing. Could this also be why it isn't starting like it should. Is the air fuel suppose to ignite in the exhaust housing or in the combustion camber. Sorry for the terrible grammar.
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Post by racket on Jan 29, 2014 15:48:04 GMT -5
Hi Blake
Probably better to blow the air onto the turbine wheel rather than into the combustor where the air could blow back out the compressor , some guys have fitted/brazed a delivery tube into the turbine scroll to blow directly onto the turbine wheel tips at an optimal angle ( ~20 degrees above the tangent)
A half inch tube with 100 psi of air should get her spinning .
Combustion should be completed by half way down the combustor, prior to the main dilution holes , ...........propane can be ignited at the exhaust , it should then "pop" back into the combustor , if it doesn't , theres a problem with your fuel/air mixing , and/or too much fuel , a reduction in the fuel flow or an increase in airflow should see it "pop" back inside with an audible sound .
Cheers John
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Post by areacombustor51 on Feb 4, 2014 8:25:35 GMT -5
I've had no problem with igniting it. It pops back into the combustion camber. Ill have to try the compressed air method. And see how that goes. For start up can I light the propane then add air or air first then fuel? Also the vanes think you said keep closed for start up then open slowly while adding fuel?
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Post by racket on Feb 4, 2014 15:55:37 GMT -5
Yes , propane on , ignition , pop back into combustor , start air on , spoolup commenced , main fuel slowly added as rpm rise .
What "vanes" are you talking about keeping closed ??
Cheers John
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Post by areacombustor51 on Mar 10, 2014 20:54:47 GMT -5
GREAT NEWS I finally got my turbo jet completed self sustained and running. I've been working on this forever it seems and I've done it. I want to thank you RACKET for all your knowledge. I'am thankful for finding a forum on this topic. As of today running off propane peaking at 8 psi. Propane tank is freezing. 45 degree air temp. The turbine is very interesting to control. Almost seems to be a delayed response when adding fuel/ boost, Video/ Pic posts soon!
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Post by racket on Mar 10, 2014 23:05:11 GMT -5
Congratulations :-)
8 psi , a nice "idling" rpm ...................more fuel required,........ sit propane tank in hot water to increase its vapour pressure .
video,...... yes please .
Cheers John
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Post by stoffe64 on Mar 11, 2014 4:03:02 GMT -5
congratulations to your running Engine, im happy for you, i will be very happy too when and if i ever get my Project that far so i can start it, im stucked with the welding part due to no availability of TIG welding Equipment...congrats once again, very nice work of you!
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Post by areacombustor51 on Mar 14, 2014 13:27:53 GMT -5
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Post by racket on Mar 15, 2014 19:00:48 GMT -5
Hi Blake
Is there any "flexible" section in your air delivery tube between comp housing and combustor ??
The different expansion rates generally requires a short section of "rubber" tubing somewhere in the delivery tube to prevent something breaking under the forces of expansion , it only needs to be a couple of inches long , preferably silicone "turbo" tubing , the gap between the metal tubing ends need only be a quarter inch .
Cheers John
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Post by areacombustor51 on Mar 15, 2014 19:36:26 GMT -5
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Post by areacombustor51 on Mar 15, 2014 19:38:09 GMT -5
No flex tube in the charge pipe. I've ran it several times without any issues. Thanks for the advice
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Post by racket on Mar 15, 2014 22:12:22 GMT -5
Hi Blake
Starts and runs nicely :-)
3 psi is getting kinda low , your temperatures will be higher than at a slightly higher P2 of ~5 psi , also it gets harder to accelerate from such a low idle , easy to get into trouble .
Looking forward to seeing the higher P2 runs :-)
Cheers John
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Post by areacombustor51 on Mar 16, 2014 9:54:29 GMT -5
Using warm water to preheat the propane made a huge difference. Yes indeed it does struggle at low boost/idle? Only takes a second to pull out of low boost. So any idea on what this makes for horsepower? Also how much boost is too much. Or does it not matter haha...
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Post by finiteparts on Mar 16, 2014 11:05:41 GMT -5
Blake,
Congrats on getting it up and running...is that a variable nozzle turbo or a wastegate that you are operating with the lever and bike cable in the video? If that is a VNT, that is really cool! I have been wanting to build a small research engine out of one of my Garrett VNT turbos to play with the turbine inlet area.
If you know the turbo make and model you might be able to find a compressor map and estimate the peak allowable boost so that you don't overspeed the rotor...or you can watch for a shower of sparks coming out the exhaust pipe and listen for the vibrations of the rotor to jump up (it makes an interesting whirling noise...I had a rotor go into a severe eccentric whirl orbit due to really high oil temps (thus low oil viscosity))...but I am guessing that you don't want that! hehee!
~ Chris
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Post by areacombustor51 on Mar 16, 2014 13:21:30 GMT -5
The variable vanes are in the exhaust housing. I must have it set in the right range to make boost. Also works as a boost brake. Pull the lever and boost drops under fuel delivery. Almost works like launch control. Pull lever turn up fuel and release for boost.
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