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Post by racket on Jun 6, 2022 20:34:40 GMT -5
Hi
Before you go looking for a new ignitor box.
When you say it spools really slow , could you have a battery problem ?
What voltage are you feeding to her , is it the same as indicated on the ignitor and starter motor ??
You should be able to hear the ignitor firing with a loud "crack "
Cheers John
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Post by racket on Jun 5, 2022 3:26:14 GMT -5
Hi Guys Did a flow test on the current fuel manifold with a 35 psi pressure delivery/drop across the injectors with a total flow of ~4 lpm , around 30% above expected flow . Only a marginal flow difference between injectors , probably <5% which is expected due to them having slightly different bore diameters etc etc . Fuel "speed" out of the injectors was fairly "squirty" , so switching to the 16G needles is worth trying . Couple of pics showing differences Tomorrow I'll go and hopefully source my thimble "ears" Cheers John
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Post by racket on Jun 4, 2022 22:26:34 GMT -5
Hi Guys
A bit of an update .
The flametube appears to have suffered a bit of front wall buckling due to the combustion taking place against it , a good result in that there isn't any of the flametube length/volume being wasted , but its not something that can be left as is , so a number of small holes will be drilled in the front wall to hopefully keep the combustion off it .
With the flametube front wall probably running red hot , theres a chance it has been causing the abberant T2 temps either from some "recirculation ??" of hot air off the wall or radiant heat affecting the reading even though the thermo is shielded from radiation .
I'm going to fit "ears" onto the thimbles in the front wall to hopefully improve the airflow distribution from the thimble holes , currently I feel some holes are flowing more as they are exposed to the general flow direction of the air as it heads towards the shaft tunnel whereas those on the other side of the thimble are in a bit of a "shadow" .
I've purchased a 100 box of 16G X 40 mm syringe needles which I might use to replace the current injection needles with to slow down the fuel velocity entering the evap tubes especially at higher power setting where I'm getting larger differences in TOT temps between my two thermocouples in the jetpipe ................I might do a flow check of fuel first to make sure all injectors are flowing the same , the usual propane test appears to produce similar flame heights , but maybe at high liquid fuel flow rates there are "problems" with the fuel manifold , best to do a real world check :-)
A check of the A/B hot streak flow rate produced pathetic results , a Paper I read indicated a 2 times flametube can flow is required on large multi canned axial engines to produce a reliable hotstreak , and as my fuel pressures are kinda low , I'll be needing a 5 mm tube for the hotstreak rather than the ~1.5 mm one presently being used which was a repurposed flametube inside static pressure proble line .
Otherwise , the engine appears to be OK inside .
Cheers John
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Post by racket on Jun 4, 2022 19:03:40 GMT -5
Hi Scott
Ready to start turning those tyres :-)
Evolution is progressing nicely as both Andy and myself hoped it would with your input .
The engine has performed much better than both of our initial expectations , it was a radical design that fired up and "worked" , but as with all engines theres going to be "improvements" that can be made with the benefits of hindsight ..............heh heh , I've spent years, and with a lot of dead parts, on my engines getting the gremlins out of them , as do the full sized aero engine manufacturers when we read their Papers .
The 10/110 is a good matching of readily available rotor parts , and considering you've run it up to well past its design 3.5 :1 PR ( 2.5 Bar P2) without any problems , the basic design appears to be sound :-)
Looking forward to the kart breaking records :-)
Cheers John
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Post by racket on May 26, 2022 17:11:27 GMT -5
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Post by racket on May 26, 2022 16:50:27 GMT -5
Fuel is "discharged" into the flametube , the mass of fuel ignites , but because it isn't finely atomised its slow to burn , resulting in a flame exiting the turbine wheel and igniting the afterburner fuel spray .
Plenty of info on the Net , do a Google
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Post by racket on May 25, 2022 0:13:45 GMT -5
Hi Guys
Woke up to a sunny morning instead of the forecast rain so hurriedly got ready for a test run ..............wasn't a good idea , it was one of those "do not operate machinery" days for me , the brain wasn't working :-(
Engine fired up OK , but lots of "vibration" , I think its from the turbulence in the A/B can , it shook the test stand to the point where my gauges camera couldn't record any numbers , thankfully the hand held one did .
Numbers were similar to last test , fuel pressure vs P2 , temps a tad lower but so was P4t from the lowered backpressure as a result of a 132 mm jetnozzles vs the previous 118 mm nozzle .
Thrust reading didn't eventuate , my stuffup , duh , ...... forgot to turn it on before spoolup , so numbers were meaningless once I did .
Couldn't get A/B to ignite once I started feeding fuel to it , I'll be needing a larger hot streak .
There were some "positives??" from the testrun , but they were mainly about things that need rectifying .
I won't put up any video as its not worth watching .
Will need to pull the engine and remove the outer can to make changes , so next test sometime next month .
Cheers John
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Post by racket on May 21, 2022 18:48:57 GMT -5
Hi Andy
Now thats a "spark" :-)
Cheers John
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Post by racket on May 18, 2022 21:06:13 GMT -5
Hi Guys Bit of an update . I was a tad "concerned" about my max thrust reading of 225 lbs as it was exactly the same "number" as a previous test , I never get "exact" numbers So I loaded up a backpack with ~40 lbs of old fishing sinkers and with that on my back I weighed myself on the "butchers" thrust scale ...............I weighed exactly 225 lbs ,..............interesting Onto the bathroom scales and I weighed ~240 lbs with the load of lead on my back . The thrust scales must have a "stop" inside them to limit movement of the "spring" , so my 225 lbs of thrust on the last test run was somewhat under what it realy was ........nice I've decided to fit the afterburner to do some "dry" testing with it in place................well maybe "wet" if all goes well Cheers John
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Post by racket on May 16, 2022 4:11:45 GMT -5
Hi Andy
Yep , sure will , I just need to "crunch the numbers" tomorrow to see where the changes were from the previous test before I get the A/B on her .
My T2 numbers are still pretty high , gotta find out why , maybe I need more clipping of the exducer to get even further from the surge line .
LOL, I love the spoolup roar as the fuel ignites :-)
Cheers John
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Post by racket on May 16, 2022 1:32:37 GMT -5
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Post by racket on May 15, 2022 17:42:28 GMT -5
Hi Patty
I guess we'll find out in the next coupla days :-)
Teststand is loaded on the trailer ready to go , weather should improve tomorrow .
Exducer throat now the same as I originally had , a 40 degree clip at the tip , but this time I'll have extra gas deflection at the inducer from the tighter NGV , to help power the comp
Cheers John
Cheers John
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Post by racket on May 13, 2022 21:33:32 GMT -5
Yep , originally CIG , then BOC , both ripped us off , when BOC rang and asked me to do a survey on why I'd cancelled my account , ................did I give them a mouthful ............bastards , I only used 1 cylinder of acyt in 10 years , I musta paid for that cylinder several times over ...............then to try rubbing salt in my wounds , the bastards wanted to know if I'd like to try their buy/refill system that they'd never thought to tell me about.............they can rot in hell , ripoff bastards .
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Post by racket on May 13, 2022 18:45:56 GMT -5
Hi Ben
Nice to see progress is being made :-)
I've never used the plasma function on my machine, only the TIG , my nice MIG machine hasn't been used for a decade :-(
I like my oxy torch for a lot of jobs , it use to be expensive hiring cylinders , but thankful we can now purchase and swap which is much better for this DIY'er , I must have wasted enough money on cylinder hire over 40 years to buy a decent car .
Cheers John
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Post by racket on May 11, 2022 22:53:30 GMT -5
Hi Guys
Its a bit quiet on the Site at present , isn't anybody doing anything ?? :-(
Picked up my rotor from the balancing guy this morning , hopefully have the engine back on the test stand in a couple of days .
Meanwhile I've been getting the afterburner electrics sorted in case they're required soon .
Hotstreak plumbing made up , with a 12V solenoid allowing combustor fuel bleed to be used .
Cheers John
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