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Post by Johansson on Mar 26, 2024 15:28:10 GMT -5
Nice! Best of luck with the maiden run!
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Post by wannabebuilderuk on Mar 27, 2024 15:33:36 GMT -5
So checking the electronics finds a slight bug with the 24v to 12v 30a converter where it shuts off for 5s when you apply the oil pump motor load if its already receiving 24v in but if a load is connected when the 24v begins its fine as can see in vid. Technically it's not a problem just an annoyance as egt gauge displays volts for 60s so it resets the timer and I'd rather not have the pump running for a minute whilst waiting for the gauge so I'll get a 2nd mini buck converter for the 12v gauges. imgur.com/OWoghD0 |
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Post by wannabebuilderuk on Mar 28, 2024 11:56:13 GMT -5
Successful oil test, she's ready to go! imgur.com/UoiYCe6nice 50psi cold and no play/leak in the bearing/seals, only a little leak around the bypass channel but what engine doesn't leak  Got a 2nd buck converter coming to fix the gauges switching off problem (give them a separate power supply) |
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Post by wannabebuilderuk on Mar 29, 2024 13:02:17 GMT -5
Well I couldn't resist giving it a little go at home instead of far away from the village, the blower instantly got stuck against the inlet and choked it out and throttle was a bit sensitive hence combo gave large undesirable flames but no damage or insane over temp and she wants to run! imgur.com/6tsMcid |
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Post by racket on Mar 29, 2024 16:32:41 GMT -5
Congratulations ...............both you and the engine survived , .... I'd call it a success :-)
Those first few spoolup attempts are the hardest until you get a feel for what your engine wants .
Enjoy the challenge , the results will be worth it.
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Post by wannabebuilderuk on Mar 29, 2024 17:21:26 GMT -5
Congratulations ...............both you and the engine survived , .... I'd call it a success :-) Those first few spoolup attempts are the hardest until you get a feel for what your engine wants . Enjoy the challenge , the results will be worth it. You ain't kidding, I think the pwm was at maybe 1/2 of what I have assumed would be the required speed for idle of 4gph and seemed to be feeding it too much, perhaps the atomization is so good it's burning more efficiently and thus an "eco" jet 😂 Was a slight electrical fire with the 24v to 12v converter spade connector on the 12v side going to the relay which must have a bad connection as it acted like a resistor and started burning the electrical tape but the fix for the gauges should also solve that problem but otherwise it's just fine tuning as she wants to let rip. Trimmed down the end of the blower so it's more of a rattle fit which should stop it getting stuck to the intake, was nice hearing her start to spool up at the 12s mark in the vid 😁 |
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Post by wannabebuilderuk on Mar 31, 2024 12:07:07 GMT -5
After almost 4 years, she runs 😁 Some combustion instability so need to investigate that and some oil leaking from outlet so think my holes in the oil tank lid are too small and causing back pressure or I haven't tightened the bolts enough but she runs so I'm happy! www.instagram.com/reel/C5L40nUsF5n/?igsh=MWx4b2lidW5xcGd0aQ== |
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richardm
Senior Member
Joined: June 2022
Posts: 413
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Post by richardm on Mar 31, 2024 12:19:59 GMT -5
I can see that from the smile in your face ! Congrats!
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Post by wannabebuilderuk on Mar 31, 2024 14:26:35 GMT -5
Well everything looks good, full throttle was showing about 30psi on the gauge which is a nice 3:1 PR, exhaust temps were pretty low, would go up to 500ish when starting but drop down to 250 at idle and 300ish when ramping up which either means the egt probe is in a dead spot for the true heat or she runs really cool although when I put my hand in the flow it wasn't actually that hot feeling surprisingly despite it blowing the trees 20m back! As you can hear from the vid combustion seems a little unstable, not sure what is causing that but flame tube looks to be in good nick with no hot spots but a lot of soot on the back of the nozzle. Surprisingly on the second attempt the blower died a couple of seconds after ignition yet she managed to spool up herself with without the blower, she really wants to run!!!   imgur.com/POONmqy |
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Post by racket on Mar 31, 2024 16:51:08 GMT -5
Congratulations :-)
Yep a bit of combustion issue , have you done an insitu fuel flow check to see if the flow is consistent, sounds a tad intermittent .
Certainly running cool , still got soot on your turb wheel.
Very good result for a first spoolup :-)
Now you can have some fun getting it sorted and fitting a jetnozzle to make some noise .
Cheers
John
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Post by wannabebuilderuk on Mar 31, 2024 17:46:29 GMT -5
Congratulations :-) Yep a bit of combustion issue , have you done an insitu fuel flow check to see if the flow is consistent, sounds a tad intermittent . Certainly running cool , still got soot on your turb wheel. Very good result for a first spoolup :-) Now you can have some fun getting it sorted and fitting a jetnozzle to make some noise . Cheers John Flow should be pretty constant being a gear pump and running at high pressure, plus all the tests I did of the fuel system didn't show many issues. One person commented it sounds like compressor surging which would explain why the p2 gauge is moving so violently although the holes on the flame tube are the correct size so not sure why it would be surging at all rpms or having fuel flow issues? At least it's running and certainly got some potential 😁 |
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Post by racket on Mar 31, 2024 18:58:47 GMT -5
Shouldn't be surge with the turbo configuration you have , the 1.39 A/R scroll isn't the smallest and your comp inducer to turb exducer ratio certainly isn't a problem.
Then we come to your temps , they're nice and "normal" for an open exhaust .
Unless theres some sort of restriction between turbo and combustor to produce surge , but a string in the comp housing inlet will indicate if theres reversing flows .
Could there be a cavitation problem with fueling, thats why I suggested an insitu test to see if the spray is constant and not fluctuating .
Just a minor problem :-)
Cheers
John
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Post by wannabebuilderuk on Mar 31, 2024 19:07:57 GMT -5
Shouldn't be surge with the turbo configuration you have , the 1.39 A/R scroll isn't the smallest and your comp inducer to turb exducer ratio certainly isn't a problem. Then we come to your temps , they're nice and "normal" for an open exhaust . Unless theres some sort of restriction between turbo and combustor to produce surge , but a string in the comp housing inlet will indicate if theres reversing flows . Could there be a cavitation problem with fueling, thats why I suggested an insitu test to see if the spray is constant and not fluctuating . Just a minor problem :-) Cheers John The elbow to the turbine is a continuous profile of the inlet so minimal restrictions, how would you recommend approaching the test for potential fuel problems being I can't exactly see inside lol I'll add a small bit of string to the inlet just to rule out surge, will be sufficiently attached to not get ingested 😁 Hopefully if it's just fuel related then I don't have to worry about potential damage like I could get with surge anyway. |
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Post by racket on Mar 31, 2024 19:24:38 GMT -5
I was just looking through my "notes ??" from the TV84 build and found I needed to fit an anti pulse chamber on my fuel delivery as I was experiencing P2 and P4t bouncing .
Do you have a pressure gauge on your fuel delivery line to see if theres fluctuations ??
You'll probably need a jetnozzle of ~75mm dia
Cheers
John
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Post by wannabebuilderuk on Mar 31, 2024 19:58:12 GMT -5
I was just looking through my "notes ??" from the TV84 build and found I needed to fit an anti pulse chamber on my fuel delivery as I was experiencing P2 and P4t bouncing . Do you have a pressure gauge on your fuel delivery line to see if theres fluctuations ?? You'll probably need a jetnozzle of ~75mm dia Cheers John The large glycerine gauge on the control box is connected via the grease gun hose just after the pressure relief valve, the fact I've got the gauge on the hose probably absorbs any fluctuations as no doubt there will be air between the gauge and the kerosene but I didn't really notice any fluctuations and if there was the air in the hose would act like an accumulator and reduce the pulsing right? It's odd that it could be pulsing enough to cause this when it's only a 1ml/r pump so any pulsing should be minimal and all tests I did showed a nice continuous spray of fuel... It is certainly bizarre lol |
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