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Post by smithy1 on Dec 21, 2015 19:38:47 GMT -5
Hi Smithy Now thats an interesting "pre combustor" mixing pot . Cheers John Yes...yes it is..has a nice set of "swirl" vanes, also has twin igniter ports.... but they are easily blocked off. The primary holes and slots are behind the upper shield and protected from some of the unwanted air flow oddities. I wonder how well it would work in the outer in the 6041..? The C20 & C30 have the same threads for the fuel nozzle so at least they're kinda interchangeable. I flowed one of my "modified" C30 fuel nozzles this morning....has a real nice "fine mist cone" at just 20psi...!  I'll have to do some number crunching to see if the FT is a viable option. At this stage I think I'll still go with your idea though....failing that I can fiddle with the parts I have on hand. Smithy. |
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Post by smithy1 on Dec 28, 2015 20:50:28 GMT -5
Hi Gentlemen,
Firstly...Merry Xmas and Happy New Year to all..!
I've had a chance to do a little modding to the "Beast" over the last week or so....have taken the "Round-House" evaporator system off the top of the original 6041 flame tube....as suspected, two of the evap "J" tubes were quite badly burnt/melted....so I made a hole large enough for the C20B upper combustion liner to sit whilst keeping the overall height of the flame tube as it was originally. Just need to weld it all together, I'm thinking several tack welds as per John's original method rather than a full bead all the way round, hopefully to help keep cracking to a minimum. I've run out of Argon for my tig....so a trip to my local welding supply place is required.
Thread has been cut in the outer CC for the C20B fuel nozzle. I've not made accommodation for the C20B igniter as yet, so I'll use the original spark plug for the time being.
I have also made some new connections and fittings for a nice SS braided -4 fuel line which will go from the flow control/cut-off tap to the new fuel nozzle, I then connected the whole lot to the original fuel pump and gave it a spin....I'm getting a nice fine spray cone at the old idle setting... and as the throttle is increased I'm also seeing a good increase in flow and spray pattern....Once I get it all back together I'll do a few test starts/runs to establish proper idle and max flows etc...I suspect I'll need to make some adjustments but it's all part of the job.
Hopefully it will be a nice mod which works as intended. My area numbers seem to match within ~4-5% so I "should" be good to go. 95% of John's original "generous" flame tube has been retained and since it worked extremely well I don't see much of a change happening. As long as my fuel and ignition system works as I hope it will, we should have a "propane-less" starting turbine.
Cheers,
Smithy.
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Post by racket on Dec 28, 2015 22:29:01 GMT -5
Hi Smithy
Excellent news :-)
Could you post a few pics of the new bits, as well as the burnt evap as I'm curious to figure out "why" .
LOL, yeh a Merry Christmas and a Happy New Year , I'm still cleaning up and putting things back where they should be after a busy Christmas after a lot of the family stayed for an "extended" holiday, it was good but a bit tiring, I'm knackered , thankfully the weather has been kind, pleasant 25 C max most days .
Cheers
John
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Post by smithy1 on Dec 29, 2015 14:29:57 GMT -5
Hi John, I'll take a couple of pics this afternoon for you...it ain't pretty but it should be functional. I had to cut the bottom off the original flame tube to extract the round-house/J tube assembly..."J" tubes wouldn't fit through the hole in the top, no matter which way I had my tongue out   I've managed to tack it all back together in it's original spot so it should be fine. I've also tacked the C20B combustion liner "top-cap" in place...I think I'll do a few test starts to make sure it works as intended before I weld it on properly. I've also decided to "drill and tap" the outer top case to accept the C20B igniter, should be easy enough to do, I'll need to angle it to the same shape as the outer case but this shouldn't be too much of an issue, the igniter hole in the C20B cap is quite flexible, I'll just point it in the general direction  Like you, Christine and I had family over at our place for Xmas day...~20 people all together... I was "knackered" at the end of the day too. Boxing day we had a 4hr Sydney Harbour Cruise/lunch to watch the start of the Sydney-Hobart yacht race...I've never seen so many vessels in such close proximity...lots of close calls too, it's a wonder there weren't any big collisions..!  Cheers, Smithy. |
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Post by racket on Dec 29, 2015 16:07:13 GMT -5
Hi Smithy
LOL.............it wasn't the prettiest in the first place ;-)
I'll look forward to the pics
Cheers
John
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Post by smithy1 on Dec 30, 2015 13:40:51 GMT -5
Hi John, A few pics for you: C20B "liner cap" grafted onto the original flame tube. I may have to give it a few more "primary zone" holes to help it along a bit....I'll try it without first....It's easier to add holes afterwards, but rather difficult to fill them in if not required.  The offending "J" vaporizer tubes. The missing tube was only hanging on by the skin of it's teeth....~1/4 of it's dia.   New thread for C20B fuel nozzle prior to drilling and tapping for igniter plug.  Partly finished starter "socket".  Outer case fitted with C20B fuel nozzle and igniter, note the original spark plug has been retained.  I'll probably give the outer combustion casing a new coat of high-temp paint, just to make it look a little nicer. Should be ready for a few test runs in a week or two after the Xmas/New Year break. This "may" be the first "non-propane" full fuel start DIY engine in Aus..! Cheers, Smithy. |
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Post by racket on Dec 30, 2015 15:24:53 GMT -5
Hi Smithy
You have been busy .
C20 cap looks good sitting on top .
That evaporator has got me intrigued , its next door neighbour looks like new, I tried to make everything as "symmetrical" as possible to minimise the chances of this happening , I guess I can put it down to an "unknown" .
What does the rest of the"dead" evap look like , did it just blow a hole out ??
That would have been an interesting turning job on the outer can to fit the spray nozzle , she looks good with the nozzle and ignitor fitted , very professional job .
Starter coupling is looking the part :-)
How did you cut out the evap section so neatly ??
Thanks for the pics , they're much appreciated, always nice to see development work.
Cheers
John
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Post by smithy1 on Dec 30, 2015 16:28:50 GMT -5
Hi John, The "dead" evap actually had two holes blown in it, one as you can see, the other was on the opposite side of the "elbow", I suspect it may have been a miss-directed fuel spray or something has gone amiss with it's spray direction/pattern, the spray hole may be partially blocked or similar....the one right next to it is indeed fine as are all the others apart from the "other" one next to the dead one, it also has signs of heat stress, possibly a result of the blown out one. Yeah...turning the mounting flange/boss for the fuel nozzle was...um...interesting, I had the whole outer case fitted to our big old lathe at my work, used the 3-jaw chuck from the inside to hold it, then on "very slow" I turned the boss down to the required depth and opened the hole to the correct "tapping size" for the fuel nozzle, this enabled me to get both center and square to each other....was actually quite simple in the end.... but I was a bit wary of stuffing it up, all good and the final result is ok. The igniter thread was a bit more difficult to get right as the surface is angled & curved, I just measured the center-center of the igniter and fuel nozzle holes on the "cap", transferred this info to the outer case, drilled and tapped.... and it just "worked". Stater coupling is a "work in progress"....I used an old 1-1/8" socket and cut & turned the hex part off and "interference fitted" an ~8mm deep piece of it into a lump of solid brass rod. I made certain to allow clearance for the "dome" of the compressor nut, just need to trim some of the excess brass from it and drill & tap for a pair of grub screws and it should be good to go. Still tossing up on which brushless motor to use though, I still have the old Castle 1717 1580kv motor and a new "Leopard" 4282 2000kv motor, the latter is rated at 3500 watts and 120Amps would probably be ok. Both sport 5mm shaft diams. I'd prefer 6mm or 8mm but beggars can't be choosers..! The old evap system was cut out using a Dremel and several small cut-off wheels....I just measured the hole I needed from the outer dia and the C20B cap fitted nicely. A few tack welds to hold it in place with the tig and all is good. Cheers, Smithy. |
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Post by racket on Dec 30, 2015 19:56:34 GMT -5
Hi Smithy
So the outlet end of the evap was OK , just a couple of blow outs, sounds like faulty tubing .
The amount of fuel going into the evap shouldn't catch fire easily because of the excessively rich mixture , just one of those things that happen with prototypes .
Is the C20 fuel nozzle thread a "one off" type ??
LOL, 3.5 Kw should get her spinning , but that 2000 kv sounds a bit high , she'd be a high revving motor , maybe the lower kv motor would be better as it might have a bit more torque at the lower rpm .
Cheers
John
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Post by smithy1 on Dec 31, 2015 16:56:36 GMT -5
Hi John,
Yeah...just one of those things I guess with the evaps..!
The C20B fuel nozzle thread is a strange one...15/16" x 20tpi. I could have used the one from my work but I didn't want to risk damaging it... so but I bought a tap from fleabay. The igniter thread is 11/16" x 24tpi. I believe the C30 fuel nozzle thread is 1"x 20tpi, I originally thought they were the same as the C20 but I was mistaken.
I think you're right with the brushless motors...I'll stick with the Castle 1717 at 1580kv....I've read some have had 6kw out of them..! Although...there's not a lot of load on the 6041 rotor even with 70psi oil pressure so the 2000kv may well be ok, experiments shall need to be done methinks.
Cheers,
Smithy
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Post by smithy1 on Jan 13, 2016 13:37:42 GMT -5
Hi All, John...I've finally managed to get the modified flame tube into the "Beast", all the fuel and igniter lines are now installed and working. I've also fitted a "back-up" propane start system in case the "fuel start" doesn't work as hoped. I'll hopefully be able to give it a bit of a test run this coming Saturday afternoon to determine if I need to change or modify the fuel delivery or require higher fuel flows/pressures etc...I've even got a setup to allow a "series" connection of two fuel pumps to help if required....she's getting quite complicated which goes against my normal "KISS" principle. The C20B igniter system is now powered by a separate 4 cell Li-Po battery, just a small one of 2200mah capacity is sufficient, gives a decent spark/rate... plus I have plenty of batteries which I also use for my multirotors..! I have also managed to cobble together 4 x C20B fuel nozzles (from U/S parts) of varying flows at an inlet pressure of 50psi, so I at least have something to fiddle with if the original proves unsatisfactory. I did a quick light-off test to see if my "soft-light" propane system works...and it does, no more sudden "POP" when it lights now...so all good in that department. Andrew...I've now not got 2 x 8400mah Li-Fe 4cell 30C batteries connected in parallel....so I now have a solid 13.8-14v (with 250amps) available and a goodly 16800mah of capacity behind it, as you're aware, they're 14.4v straight off the charger....should work nicely....thanks for the idea.. Cheers, Smithy. |
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Post by racket on Jan 13, 2016 15:46:59 GMT -5
Hi Smithy
We'll be looking forward to hear how the spoolup goes .
Some video please :-)
Cheers
John
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Post by smithy1 on Jan 13, 2016 17:47:43 GMT -5
Hi Smithy We'll be looking forward to hear how the spoolup goes . Some video please :-) Cheers John Me too...I'll be sure to forget the video.. I'm like you John, hopeless when it comes cameras etc...Always remember to get it ready and turn it on after the fact... Must be my old age, Alzheimer's and/or Dementia catching up with me..now...where's my spoon..?? I think as long as I keep a keen eye on the temps and give it plenty of air I should be ok....not much can go wrong if the temps are kept under control. Cheers, Smithy. |
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Post by enginewhisperer on Jan 13, 2016 18:04:47 GMT -5
I'm keen to see how this goes - it might be a nice way to do my 6041 engine when I finally get the time to finish it!
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Post by smithy1 on Jan 13, 2016 19:17:28 GMT -5
I'm keen to see how this goes - it might be a nice way to do my 6041 engine when I finally get the time to finish it! You're not the only one Andrew....when I do a few "test" engine runs on Saturday I'll know more, I suspect I'll have to "tweak" a few things but that's just part of the process. If I need more fuel pressure or flow I might just run a pair of pumps in series and see if that helps...can't hurt to try I guess. First up I'll run the clone 044 pump I have at 13.8v and see if that does the job. According to the figures I did a month or so back it should be enough...but there's always bound to be a few "unknowns" to spoil the fun. There's no guarantee the engine will run at all...but the numbers I have say it should at least get to idle. I'll have a few different flow rate fuel nozzles with me to try, they're easy to change (2-min job), so I have that option as well as different voltages, pump setups etc....All in a days work. The AB is working quite well now so until the next problem arises I'll leave it alone. Why does the work on these things never stop?? It's supposed to just be a hobby isn't it?? There's always something to sort out/repair/modify after a days running or testing etc.. I guess it's just that alluring sound of that spooling turbine that gets us every time...I've heard it a zillion times before...but I still love it..! Cheers, Smithy. |
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I'll have to do some number crunching to see if the FT is a viable option.
