mitch
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Post by mitch on Jan 11, 2015 22:41:08 GMT -5
www.youtube.com/watch?v=h8QS2kLFr40here is the first runaway that happened, but because of the intake elbow blowing off, I did not know it was a "runaway". Fuel pressure was very low in this run... The gauge was bobbing around 10 psi. I think the "boost" (which would be called "p2", correct?) spiked at above 20 psi when the elbow let loose. Notice that the engine and stand did not move at all at that p2... This makes me think that the p2 of the first video I posted was much higher than 20 psi
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Post by racket on Jan 12, 2015 1:24:28 GMT -5
Hi Mitch
That one didn't look good :-( ................too much "rubber" in the delivery pipework , it won't survive compressed air temps up near 200 C , we need metal pipework with just a very short section of rubber to give some expansionary "give" , the 2 ends of the metal pipework needs to be within a 1/4" of each other , the rubber muff simply can't blow off that way .
Cheers John
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mitch
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Post by mitch on Jan 12, 2015 8:30:50 GMT -5
racket, that was something I was planning on doing in the future, as this run was supposed to not see p2 pressures above ~10 psi. Something strange I noticed in the video though... at about 8-10 seconds in, you can see a stream of kerosene spraying out of the back of the combustion chamber! I am assuming my hillbilly lockwasher gasket for the nozzle is clogging up the fuel flow, or causing a massive leak, as suggested by finiteparts. I wish those darn hago nozzles were just good old NPT threaded!
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mitch
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Joined: August 2014
Posts: 285
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Post by mitch on Jan 12, 2015 16:40:40 GMT -5
Here are a few pics of the flame tube too. I noticed a large hotspot when I took the combustion chamber apart after the very short runs it had. Notice how the hot spot is directly in front of the air inlet tube. I believe the pooling of fuel beneath the flame tube contributed to this hotspot
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mitch
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Posts: 285
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Post by mitch on Jan 12, 2015 16:42:23 GMT -5
Another view of the hot spot
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Post by racket on Jan 12, 2015 17:46:07 GMT -5
Hi Mitch
Interesting that the only colouration is at the Tertiary end , there doesn't appear to have been any combustion taking place at the Primary end , yep, you'll need to do an "atmospheric" test of the fuel system so you can observe whats actually happening in the combustor .
Cheers John
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mitch
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Joined: August 2014
Posts: 285
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Post by mitch on Jan 12, 2015 21:59:57 GMT -5
It is interesting. I'l have time to do a test of the fuel system this weekend. I'll also note that the flame tube is made of 10 gauge mild steel, so it is fairly heavy duty.
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mitch
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Joined: August 2014
Posts: 285
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Post by mitch on Jan 17, 2015 18:27:16 GMT -5
I did some testing with the nozzle outside of the chamber today, and found that the nozzle wasn't working properly, and was spraying one thin stream out at lower pressures. The fittings also leaked a decent amount. After switching to a lower flowing nozzle, replacing the homemade lockwasher gasket with a rubber one, and tightening the fittings, the leaks almost all disappeared.
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mitch
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Joined: August 2014
Posts: 285
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Post by mitch on Jan 17, 2015 18:45:17 GMT -5
I have also decided that before I do any more testing with the engine, I am going to be completely re- doing the engine's oil system and fuel system. The oil system is made up of a mix of hard lines and vinyl soft lines. The vinyl lines are not made to handle oils, so I will be switching to a soft line that is designed for oil use. I will also be putting a new oil pump in, that is rated to handle oil and that doesn't have a "demand" system built into it .The fuel system will have the same done to it, it will all be hard line and will be plumbed more neatly throughout the assembly.
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Post by racket on Jan 17, 2015 20:34:45 GMT -5
Hi Mitch
Try and have the oil line in metal anywhere near the turbo , radiant heat from the turb scroll will degrade any "rubber" hose, a burst line will mean a fire ball if it sprays on the scroll .
Cheers John
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mitch
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Posts: 285
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Post by mitch on Jan 17, 2015 21:17:09 GMT -5
Okay, thanks for the input racket. I will keep that in mind. As you have seen, my current setup uses a rubber bypass hose that feeds through the core of the turbo for added cooling (I assumed rubber would work okay for the short runs the engine would be seeing during testing), but I will be sure to make that a metal line in the future.
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mitch
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Joined: August 2014
Posts: 285
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Post by mitch on Feb 2, 2015 13:00:55 GMT -5
Got some parts around to start building the ECU. The oil pump and motor will have to wait a little bit till I get a break from school (it's much easier to work on electrical things in a dorm room than oil pumps and motors lol)
Will include pics later, but I plan on having the arduino mega as the brains, 2 lcd screens to show oil pressure, temp, egt, etc. Will include a control to cut fuel pump power if certain parameters are exceeded, etc.
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mitch
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Joined: August 2014
Posts: 285
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Post by mitch on Feb 10, 2015 10:57:54 GMT -5
box of tangled up electronics parts
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Post by Richard OConnell on Feb 10, 2015 13:12:27 GMT -5
Nice box.. looks like my desk at work
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mitch
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Joined: August 2014
Posts: 285
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Post by mitch on Feb 23, 2015 11:21:43 GMT -5
Worked on making supports for the free power turbine this weekend, and started to make the intake elbow for the combustion chamber
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