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Post by racket on Jan 31, 2016 22:11:45 GMT -5
Hi Smithy
I can see you're circling round and round , closing in on the best outcome :-)
Yep , the joys of R and D .
Cheers
John
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Post by smithy1 on Feb 1, 2016 13:49:18 GMT -5
Hi Smithy I can see you're circling round and round , closing in on the best outcome :-) Yep , the joys of R and D . Cheers John Pfffttt..! Yep, still going round and round and round....I'll get there eventually, no hurry, as long as I don't melt/break anything along the way.  Temps at idle, ~4.5psi P2 are still quite a bit lower than I was expecting, I did a couple of starts last Saturday and both of them had EGT's of just a tad over 400C... Rather confusing sometimes.  Cheers, Smithy. |
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Post by racket on Feb 10, 2016 18:16:39 GMT -5
Hi Smithy
How did the new mods perform at the car show last weekend ?
Cheers
John
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Post by smithy1 on Feb 11, 2016 14:01:16 GMT -5
Hi Smithy How did the new mods perform at the car show last weekend ? Cheers John Hi John, Sadly I didn't get to run the "Beast" due to the confines of the area I had, there were wandering people, small children and show cars just too close to be considered safe, so I made an "executive decision" not to run  No harm done. I did however get to run the little dragster, which as usual was a crowd pleaser..  I have another event this coming Sunday at Kernell, so hopefully I'll get a chance to give the beast an engine run ....or three. During the week I have received a few more items which I had on order, I then set about doing the some minor mods etc... I'll do a fresh post for them with a few pics, explanations etc... Cheers, Smithy. |
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Post by Johansson on Feb 11, 2016 14:33:57 GMT -5
Hi Smithy How did the new mods perform at the car show last weekend ? Cheers John Hi John, Sadly I didn't get to run the "Beast" due to the confines of the area I had, there were wandering people, small children and show cars just too close to be considered safe, so I made an "executive decision" not to run. Sounds like perfectly normal race conditions for our jet kick.  |
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Post by smithy1 on Feb 11, 2016 14:37:48 GMT -5
As mentioned above, I have received a few "upgrade" items, so during the last week I have done a few minor modifications to the Beast. The original oil cooler and hoses I had fitted some months ago, while working fine and keeping the oil cool etc..had started to weep/leak oil, not ideal. The nylon braided hose was actually starting to weep through the braid...Porous maybe?? I don't know, but I didn't trust it any longer and decided to fit some high quality hose, fittings and a new billet aluminium cooler. My new "contracted driver"... Stuart..!  New aluminium cooler assembly with "AeroFlow" & "Goleby's" quality fittings and AN-10 "300psi" hose.  Twin Bosch 044 clone pumps, in series to produce 170+psi..!  New high quality "Goleby's" 120degree AN-10 fittings and high pressure, high flow oil cooler hoses.  Fuel system accumulator, I'll have a shorter AN-4 pipe coming soon to help clean up it's installation a bit.  Cheers, Smithy. |
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Post by racket on Feb 11, 2016 16:00:47 GMT -5
Looking nice :-)
All the best with this weekend , ..............Heh heh , always a bummer when small children are at risk of being blown over
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Post by smithy1 on Feb 11, 2016 18:29:54 GMT -5
Looking nice :-) All the best with this weekend , ..............Heh heh , always a bummer when small children are at risk of being blown over Thanks John....and yeah...the risk it not worth it...just a small toddler walking past at the wrong time could be rather nasty, I have public liability insurance but that doesn't help if a small child is hurt or worse...I do have signs up warning people of the dangers and that they should keep young children under control, most are ok but some don't read them and continue on their mindless, merry way. Most people are fine and are eager/happy to watch.... and stand in a "safe area"....What beats me sometimes are the "unknowing" inattentive people who walk right behind my jet powered machines while they're running.... and this is after clearly seeing plumes of white Jet-A1 smoke or 4 or 5m of fire spewing from the tailpipes. Sometimes people just have no idea. I always try to allow for a "safe area" near my machines, but often it's not always possible depending on the space the organizers allow me...these are the occasions where I make my "executive decisions". Cheers, Smithy. |
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Post by smithy1 on Feb 11, 2016 18:34:51 GMT -5
Sounds like perfectly normal race conditions for our jet kick. Ah...but I suspect most of the people you have at your race meetings are "switched on" to what's going on and behave accordingly....unlike a lot of the morons at some car shows I go to. As I said before....most people are ok....a small minority just have no idea.. Cheers, Smithy. |
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Post by smithy1 on Feb 15, 2016 17:30:11 GMT -5
Hi All,
I was able to do a couple of engine runs on Sunday during a local car show....as usual the "Beast" lit-off and ran up to idle nicely, I saw EGT's of ~700C during ramp up to idle which is fine.... and it quickly settled down at ~480C at idle ~3.5psi P2, I then ran up to ~20psi P2, with an EGT of ~570C and then I hit the A/B....Damn..!! Not only did it scare the crap out of the spectators, it near scared the crap out of me...and I knew it was coming... She's working extremely well now, nice burner bangs & pops etc...Lots of fun..! I then ran her up to ~35psi P2 and it's obvious she wants to go more...I didn't push past this though as she was starting to jump the wheel chocks, safety first..!
The oil pressure was a good 70psi cold and 60-65psi when warm and I didn't see the oil temp go over 65-70C all day so no issues in that department..I can now rest knowing the oil system is as it should be.
John, for the G/G fuel supply, the two 044 pumps in series work like a charm, I may have to adjust the fuel nozzle flow "down" slightly but @ 45psi fuel pressure she's idling away nicely with a pressure delta approaching 41.5psi at an idle P2 of ~3.5psi. The fuel pressure curve is very steep and just a small increase in throttle has the pressure building quickly....I did a couple of quick throttle hits and the pressure quickly rose above 150psi...so there's plenty of pressure and flow there to make use of. When at 35psi P2, the fuel pressure was ~120psi so a delta of ~85psi...a small adjustment to the fuel nozzle flows may be required, easy enough to do, just a matter of shimming the internal spring to suit...I guess it's called "development engineering"..! ;-)
Unfortunately I'm still having an "intermittent" issue with flame-out when I shut the throttle off quickly, even with the accumulator in the system....I keep the igniter running so she eventually comes back to life as the rpm and hence P2 drops and the fuel pressure overrides the P2 again. I may have to rethink this a bit but am open to suggestions. If I close the throttle slowly it's fine and there's no evidence of flame-out.
Andrew, your suggestion of the Li-Fe batteries is a winner, thanks muchly...they work perfectly and I now have no low voltage problems etc...
I did notice the wiring to the twin 044 G/G pumps was getting a tad warm so I'll set about rewiring and fitting a heavy duty relay with some heavier gauge wire to keep things safe. I guess with both pumps running she'll be pulling higher amperage. I'll rewire and fuse the system accordingly.
All in all, a good day for the "Beast".
Cheers,
Smithy.
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Post by enginewhisperer on Feb 15, 2016 18:33:49 GMT -5
Hopefully I can come and have a play again soon I've been a bit flat out moving my workshop (found out a couple of weeks ago it's been sold and I have till the end of the month to move out!) |
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Post by racket on Feb 15, 2016 19:49:00 GMT -5
Hi Smithy
Excellent news :-)
Mmmm, sounds like you might need a bit more accumulator volume , the 6041 has a pretty heavy rotor which takes some slowing down , at full throttle you're burning ~30 ml/second.
Have you had a look at the one way check valve to make sure it isn't leaking fuel back , maybe a very lightweight spring on its "ball" to help with seating , possibly do a nozzle flow test into a bottle to check how long the accumulator is supplying "extra" fuel after doing the throttle chop.
Because you have a higher idling fuel pressure now, theres less volume available in the accumulator , if your accumulator is say 100 ml and is "empty" (with 15 psit air pressure in it) prior to starting the fuel pump , then at idle with 45 psi fuel pressure ( 60 psit) , the air in the accumulator has been compressed to only ~25 ml, at full throttle its down to maybe 10 mls, so when you chop the throttle theres only half a seconds worth of fuel available.
When I was doing the TV84 development I made up a very large accumulator of ~500 ml capacity to try and even out fuel pulsing caused by a less than ideal pressure differential relief valve in my fuel control , eventually I found and fixed the relief v/v problem by making it a lot lighter in weight and was able to remove the accumulator , but the Tv84 rotor is a lot lighter and easily coped with the deceleration speed when chopping the throttle .
Maybe some of the problem is being caused by the duplex nature of your fuel nozzle , unlike the TV84s simplex nozzle working on higher pressures which would have provided finer atomisation down to a lower pressure , maybe the duplex has a "step" in the atomisation thats producing the flameout ................heh heh , I'm talking crap here to a fuel control specialist :-(
Cheers
John
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Post by smithy1 on Feb 15, 2016 20:02:41 GMT -5
Hopefully I can come and have a play again soon I've been a bit flat out moving my workshop (found out a couple of weeks ago it's been sold and I have till the end of the month to move out!) Do you need help with anything? I have a nice big Transit Van. |
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Post by smithy1 on Feb 15, 2016 20:10:23 GMT -5
Hi Smithy Excellent news :-) Mmmm, sounds like you might need a bit more accumulator volume , the 6041 has a pretty heavy rotor which takes some slowing down , at full throttle you're burning ~30 ml/second. Have you had a look at the one way check valve to make sure it isn't leaking fuel back , maybe a very lightweight spring on its "ball" to help with seating , possibly do a nozzle flow test into a bottle to check how long the accumulator is supplying "extra" fuel after doing the throttle chop. Because you have a higher idling fuel pressure now, theres less volume available in the accumulator , if your accumulator is say 100 ml and is "empty" (with 15 psit air pressure in it) prior to starting the fuel pump , then at idle with 45 psi fuel pressure ( 60 psit) , the air in the accumulator has been compressed to only ~25 ml, at full throttle its down to maybe 10 mls, so when you chop the throttle theres only half a seconds worth of fuel available. When I was doing the TV84 development I made up a very large accumulator of ~500 ml capacity to try and even out fuel pulsing caused by a less than ideal pressure differential relief valve in my fuel control , eventually I found and fixed the relief v/v problem by making it a lot lighter in weight and was able to remove the accumulator , but the Tv84 rotor is a lot lighter and easily coped with the deceleration speed when chopping the throttle . Maybe some of the problem is being caused by the duplex nature of your fuel nozzle , unlike the TV84s simplex nozzle working on higher pressures which would have provided finer atomisation down to a lower pressure , maybe the duplex has a "step" in the atomisation thats producing the flameout ................heh heh , I'm talking crap here to a fuel control specialist :-( Cheers John You could well be right John....I wonder if I connect a second accumulator via a "T" piece to effectively double the volume...may help, I'll have a good look at the check valve too....As you mention, the "duplex" nature of the fuel nozzle may be making things worse than the old vaporizer system. It's not a major issue but something I'd like to get sorted...she runs quite well as it is, just has a few niggly things I have probably introduced into the mix with my faffing about. Cheers, Smithy. |
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Post by racket on Feb 15, 2016 20:26:09 GMT -5
Hi Smithy
LOL...........it took me what seemed like years to finally get the TV84s fuel system "tuned" .
In the beginning I tried to keep it simple but eventually I just had to make a more complex controller that ended up working beautifully, but only after a lot of mods to get it "twist grip" friendly.
Looking back on it, if I'd simply fitted the little hydraulic gear pump to a 24V scooter motor and used an off the shelf "electric" throttle, it would have been a lot easier , but they weren't available 20 years ago :-(
Yep , fitting a second accumulator will certainly "broaden" the deceleration fuel supply , it might be all it'll need , hope so .
Cheers
John
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No harm done. I did however get to run the little dragster, which as usual was a crowd pleaser.. 
I have another event this coming Sunday at Kernell, so hopefully I'll get a chance to give the beast an engine run ....or three.
