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Post by racket on Mar 4, 2024 23:39:48 GMT -5
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Post by racket on Mar 5, 2024 0:26:51 GMT -5
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Post by racket on Mar 5, 2024 0:27:40 GMT -5
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ripp
Veteran Member
I'm sorry, I don't speak english, so I torment you (and myself) with a translation program,Sorry
Joined: January 2013
Posts: 231
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Post by ripp on Mar 5, 2024 2:56:32 GMT -5
Hi John, It's great that the tachometer works, now theoretically, if the combustion chamber were twice as long, the temperature would decrease? Ralph
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Post by racket on Mar 5, 2024 3:19:38 GMT -5
Hi Ralph
The tach numbers were great , just needed the reflective tape on the comp nut to be replaced and it worked perfectly :-)
The temperatures are still a concern , the fuel pressure is barely above P2 pressure and because of the diameter of the fuel manifold the hydrostatic pressure difference could be causing the large difference in temps .
I'm considering replacing the current injection syringes with one size smaller to increase the fuel pressure and make the hydrostatic component a smaller percentage of delivery pressure to the lower injectors .
There could simply be a hot streak , in which case the average temperature going through the turbine could be quite modest .
I need to spend some time viewing the videos in slow motion to absorb what is happening .
But overall todays test was a success as it was to see how the lack of IGV stator would change my manometer readings , at 4 Bar P2 the red manometer indicating flow out of the surge slot was showing minimal pressure ................LOL, maybe 4.5 Bar would see it in a neutral position with no flow being dumped :-)
The green manometer indicating pressure drop at the comp face was "off the scale" , fluid was being sucked into the engine because the vacuum/velocity was so high that it overwhelmed the manometer scale .
Cheers John
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ripp
Veteran Member
I'm sorry, I don't speak english, so I torment you (and myself) with a translation program,Sorry
Joined: January 2013
Posts: 231
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Post by ripp on Mar 5, 2024 4:34:23 GMT -5
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richardm
Senior Member
Joined: June 2022
Posts: 266
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Post by richardm on Mar 5, 2024 5:11:20 GMT -5
Nice ! BTW Is your wife still searching for her nice silver serving plate that you used for a bell mouth LOL ! I won't tell...
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Post by racket on Mar 5, 2024 22:45:39 GMT -5
Hi Ralph
Interesting thought , I've never tried bending a syringe that much
Cheers John
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ripp
Veteran Member
I'm sorry, I don't speak english, so I torment you (and myself) with a translation program,Sorry
Joined: January 2013
Posts: 231
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Post by ripp on Mar 6, 2024 0:48:27 GMT -5
Hi John, a needle can only be properly bent if it is briefly annealed. here e.g. from my beginnings Ralph
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Post by racket on Mar 6, 2024 1:45:18 GMT -5
Hi Ralph
Mmmmm , I might need to do some experimenting ............I've got lotsa different sized ones left over from previous builds to play with :-)
I've just been doing some calculations of thrust vs mass flows etc , and something isn't right , my compressor efficiencies are quite reasonable so there should be plenty of leftover energy exiting the turb wheel for producing it , but 180 lbs - 82 kgs isn't very much from a 123mm dia jetnozzle with the temperatures and pressures I have in the jetpipe .
More thinking required
Cheers John
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ripp
Veteran Member
I'm sorry, I don't speak english, so I torment you (and myself) with a translation program,Sorry
Joined: January 2013
Posts: 231
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Post by ripp on Mar 6, 2024 1:51:54 GMT -5
another note about the needles/wires, the longer they are the less the hydrostatic pressure difference will be. vs. GR180
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ripp
Veteran Member
I'm sorry, I don't speak english, so I torment you (and myself) with a translation program,Sorry
Joined: January 2013
Posts: 231
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Post by ripp on Mar 6, 2024 2:08:20 GMT -5
Hi Ralph Mmmmm , I might need to do some experimenting ............I've got lotsa different sized ones left over from previous builds to play with :-) I've just been doing some calculations of thrust vs mass flows etc , and something isn't right , my compressor efficiencies are quite reasonable so there should be plenty of leftover energy exiting the turb wheel for producing it , but 180 lbs - 82 kgs isn't very much from a 123mm dia jetnozzle with the temperatures and pressures I have in the jetpipe . More thinking required Cheers John yes I think, as long as the temperature is that high (810 C) you can't use a smaller nozzle to create more thrust. Hence my earlier question, would a Bk that was twice as long lower the temperature? Ralph
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Post by racket on Mar 6, 2024 3:03:57 GMT -5
Hi Ralph
I'm not sure if its flametube length, as the other thermocouple is indicating acceptable temperatures , maybe I need to add another 2 thermocouples to see whats happening .
But if theres choking somewhere in my NGV or turbine wheel then changing nozzle area , within reasonable amounts , can't change engine temps as the choking points prevents it .
Cheers John
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ripp
Veteran Member
I'm sorry, I don't speak english, so I torment you (and myself) with a translation program,Sorry
Joined: January 2013
Posts: 231
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Post by ripp on Mar 6, 2024 3:33:14 GMT -5
OK, I understand, thank you
Ralph
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jetric
Veteran Member
Joined: December 2014
Posts: 132
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Post by jetric on Mar 6, 2024 6:41:25 GMT -5
Hi John, Why are you not using the stainless instro tube that I sent to you for the evaporator injector tubes instead of using the syringe needles? That's why I sent you some so that you could use it for that as you were struggling to get hold of syringe needles at that time. No problem in making long injector needles with that stainless instro pipe and it can be bent to tight radiuses because it is already annealed. Richard S. Hi Ralph Interesting thought , I've never tried bending a syringe that much Cheers John
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