Working together for the better (Injector Ideas and Tests)

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NanoSoft
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Working together for the better (Injector Ideas and Tests)

Post by NanoSoft » Wed Sep 06, 2006 3:36 am

Good day to everyone. I have many valveless design ideas to test out but am out of stainless steel so I can’t (for now). So instead I have decided to try to improve my existing jets by improving injector design and augmenting. I will also be trying various other things such as water injection.

To start I decided to play with different injector designs. Because there are no readily available plans and eric and hinote are protecting there injector designs I have decided to experiment and design my own and share them and develop them in corporation with the rest of the forum.

So today I made my first prototype injector and ran some tests (none actually on a jet, yet). My injector is a simple radial injector with variable cross-section. I have provided a rough diagram and a couple pictures along with a video of it in action (Video is to big so I will cut it down and post it tomorrow). Although it is not perfect it is definitely a good start. It has a fairly even flame pattern in testing and some nice vortex’s are forming. Very interesting.

Forum members are encouraged to give constructive criticism as long as share there own injector ideas as I will be more than happy to test other people ideas and report back to the forum with the results. Hopefully together we can come up with something very interesting and free to all.

mikhail jones

P.S. Hope I didn’t offend eric or hinote, I respect there progress and why they are protecting there ideas but I think it is better to give free information so others and improve and make things better that way we advance more quickly. Think a group of 100 working together opposed to 100 working individually. Just the way I see it. That’s why I translated al those SNECMA documents so others can learn from them. One day I will finish translating the remaining pages.
Attachments
Radial Fuel Injector 007.jpg
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Radial Fuel Injector 004.jpg
Radial Fuel Injector 004.jpg (109.35 KiB) Viewed 13760 times
Prototype (RI v1) 2-Piece Adjustable 90-Degree Injector.jpg
Prototype (RI v1) 2-Piece Adjustable 90-Degree Injector.jpg (50.67 KiB) Viewed 13761 times

Eric
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re: Working together for the better (Injector Ideas and Test

Post by Eric » Wed Sep 06, 2006 4:12 am

Hi,
I have actually posted quite a bit about my designs, and even have a bunch of pictures posted. Its just a matter of searching the forum, the PHPBB search function is not even close to perfect though.

The design you show is essentially the first prototype of my "infinijectors". Larry posted a similar topic with a number of similar drawings after I mentioned how the advanced injector could basicaly be built from a tube, two nuts, and a bolt.

The basic design isnt anything of a secret as far as I am concerned. Its old, I have numerous better systems now, and the schematics for the injectors come with every set of plans I sell. I will post some diagrams and sizing equations if you are interested.

Eric
Last edited by Eric on Wed Sep 06, 2006 5:37 am, edited 1 time in total.
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Talking like a pirate does not qualify as experience, this should be common sense, as pirates have little real life experience in anything other than smelling bad, and contracting venereal diseases

hinote
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Re: Working together for the better (Injector Ideas and Test

Post by hinote » Wed Sep 06, 2006 4:39 am

NanoSoft wrote: P.S. Hope I didn’t offend eric or hinote, I respect there progress and why they are protecting there ideas but I think it is better to give free information so others and improve and make things better that way we advance more quickly. Think a group of 100 working together opposed to 100 working individually.
Just some thoughts, to add to the confusion:

My injector "progress" is based on literally hundreds of injector iterations.

I find it difficult to believe there's 100 Forum participants who could create equivalent experience levels. I suspect the only person out there who has a greater knowledge on this subject is Eric.

One result of this effort is combined with "lady luck". An educated hunch and some lucky dimensions based on TLAR--and suddenly there's something worthwhile. It's hard to just give this away, IMO.

My recent find has been largely responsible for both my recent "sub-unity" pulsejet TSFC claims. In fact, the same injectors have operated both motors--in spite of huge differences in size. Good motors--but really good injectors!

I was hoping to concentrate on fueling issues this year--but my increased understanding of PJ design has forced me to continue development of new and better valveless pulsejets for the time being.

I still feel that liquid fueling is the ultimate way to go, for pulsejets. My recent successes in propane injector development are "good enough"--and I'll be concentrating exclusively on liquid fueling in the near future.

As I've said before--SNECMA did it in the '50's--and so can I.
Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

Eric
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re: Working together for the better (Injector Ideas and Test

Post by Eric » Wed Sep 06, 2006 4:49 am

In order for it to work, it has to be split in two so that it acts as a lock nut, otherwise the threaded piece will unscrew faster than you can possibly imagine, and when it shoots out of the engine at 600 mph its not fun to be downwind of the engine

Ultimately the adjustment is great for tuning, but once you find the best setup its often good to braze or silver solder the injector into the fuel line so that it cant ever be removed.

Heres an example of a more permanant solution once an engine has been perfected and you know exactly where and how the engine likes the fuel injected.

The fuel plug will restrict the liquid propane flow, so after it passes the restriction it will expand and vaporize. Its now gas, and will spread around through the wide distribution area before squeezing through the injection gap. The gap has to have more area than the restrictor plug, or liquid fuel will build up. The fuel absorbs heat from the CC and ultimately gets injected at the right spot in the intake and at an angle of your choosing.

If you angle the injector opening you can get different effects. Like the 30 degree angle infinijectors are able to self start engines, but with higher high end flow and mixing than the classic rosscojector.


Eric
Attachments
enginevaporizergapinjection8.jpg
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NanoSoft
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re: Working together for the better (Injector Ideas and Test

Post by NanoSoft » Wed Sep 06, 2006 5:13 am

Like I said i didn't want to offend. I have learned a lot from the stuff both eric and hinote have posted and am not denying it especially eric. I did search and found quite a lot of info regarding injectors but wanted to start a discussion to further the advancement of the technology (If you can call it that). And yes eric I do have nut so I can double nut the injector setting so it won't move. Forgot to mention that.

And to hinote, I am throwing this out there so even people who have no understanding can participate because it always those who don't know it can't be done that do it. I am to starting to focus on liquid fuelling as well and these injectors are a start to a more advanced liquid fueling injector. I know very little about injectors and usually just use a tube so I am trying to step it up a notch.

Thanks for the comments.

mikhail jones

Dave_G
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Re: Working together for the better (Injector Ideas and Test

Post by Dave_G » Wed Sep 06, 2006 6:49 pm

NanoSoft wrote:
So today I made my first prototype injector and ran some tests (none actually on a jet, yet). My injector is a simple radial injector with variable cross-section. I have provided a rough diagram and a couple pictures along with a video of it in action (Video is to big so I will cut it down and post it tomorrow). Although it is not perfect it is definitely a good start. It has a fairly even flame pattern in testing and some nice vortex’s are forming. Very interesting.

mikhail jones
I have been using an injector like this for years. I made them from 10-24 SS button head screws, cross-drilled and center-bored, and threaded into the end of a flared and tapped SS tube. Very simple to make, and they give a decent enough spray pattern and provide for easy starting motors. Their downside is that flowrate _range_ is limited, and thus they have a poor turndown ratio.

The injectors I make and use now are complicated affairs, requiring almost as much time and effort as it takes me to build the rest of the motor. They are unfortunately beyond the capabilities of the average hobbyist.

NanoSoft
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re: Working together for the better (Injector Ideas and Test

Post by NanoSoft » Wed Sep 06, 2006 7:41 pm

Please go on!?

mikhail jones

Dave_G
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re: Working together for the better (Injector Ideas and Test

Post by Dave_G » Wed Sep 06, 2006 11:00 pm

Hi Mikail,

I don't really have anything to add at this time other than to say that your new injector will work well in operation as long as the flow is adjusted to suit the motor size. You've got a good design there! By sizing it properly you can control the feed pressure needed to achieve the flow required and have a pressure-modulating injector that will help your motors run with a good TSFC.

Good work!

Dave

leo
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re: Working together for the better (Injector Ideas and Test

Post by leo » Fri Sep 08, 2006 7:16 am

I think to get a good TSFC you need a low pressure difference from the injector holes or slit to the combustion chamber or inlet, so the have to be big and well spread to make good mixing, this will stop fuel flow when the pressure is high.
Before the injector you need some sort off volume for buffering fuel, for experimentation this volume can be adjustable, before that you need a restriction / regulator valve, with a higher pressure drop, to regulate fuel flow.
Just my thoughts on this subject, I don’t have the possibility to test much so this could be nonsense altogether.

milisavljevic
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re: Working together for the better

Post by milisavljevic » Fri Sep 08, 2006 9:59 am

Hello Leo --
Leo wrote: I think to get a good TSFC you need a low pressure difference from the injector holes or slit
to the combustion chamber or inlet ... this will stop fuel flow when the pressure is high.
Indeed. This is exactly the approach eventually adopted by Snecma and later by Lockwood.
Before the injector you need some sort off volume for buffering fuel, for experimentation this
volume can be adjustable, before that you need a restriction / regulator valve, with a higher
pressure drop, to regulate fuel flow.
Again, you are spot on. It is important to provide a buffer volume close to the point(s) where
fuel is injected into the engine, preferably by building this volume into the injector body(ies).
Just my thoughts on this subject ... this could be nonsense altogether.
Not at all!! Mikhail has the tools and the abilities to implement these ideas into his injectors.

Best regards,
M.
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for ye merchants who do the prop'r t'ing only if
ye be haul'd-up on charges b'fore ye ship-mates
an' threat'nd wit' forfeiture of all ye precious loot
hear this - so-called stand-up guys YE BE NOT

avast!
Cap'n M.

larry cottrill
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Re: re: Working together for the better

Post by larry cottrill » Fri Sep 08, 2006 12:27 pm

milisavljevic wrote:Hello Leo --
Leo wrote: I think to get a good TSFC you need a low pressure difference from the injector holes or slit
to the combustion chamber or inlet ... this will stop fuel flow when the pressure is high.
Indeed. This is exactly the approach eventually adopted by Snecma and later by Lockwood.
This is also fairly easy to implement, even with much cruder "injectors" like the small fuel pipes I use. In principle, I think that the best vapor fueling method, in general, is to establish regulated pressure at a valve and have your maximum pressure drop take place at the valve, not at the injector site. What this means is that you are using the needle valve (or whatever) the way it was meant to be used, to control flow, NOT pressure. In effect, the pressure in the fuel line is at (or just slightly above) ambient pressure, and when used in a pulsejet (at the appropriate fueling point) this will give perfectly synchronized "timed injection".

The point is, you are not trying to pressurize your fuel line and injector; rather, the fuel delivery system becomes an open conduit for widely variable flow. Your fuel system should be considered a "reservoir" through which fuel flows at a rate you can instantly control, not a "pressure vessel" pumping through a "nozzle" (as might be proper in a rocket engine). With this method, I have never (as far as I have been able to observe) had any of the problems reported in trying to use regulators for fueling pulsejets.

I got this method very directly from the way my welding rig works: You establish a stable pressure against a precisiely "tunable" valve and what comes out is a very stable, low pressure flow (beyond the valve in the torch body and selected size tip) that is fully controllable over a wide range. The regulator simply means that changing pressure at the supply end (the cylinder) can't gradually alter the flow you set. Of course, the regulator itself has a flow limit - I could never use my setup on a really huge motor because it would be too restrictive (even though this regulator was especially designed for relatively high flow volume).

Of course, I'm only addressing vapor fueling. The situation is very different for liquid, especially if "injection" rather than "carburetion" is the basic method adopted for fueling a given design.

L Cottrill

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re: Working together for the better (Injector Ideas and Test

Post by Berry » Fri Sep 08, 2006 6:23 pm

This is the fuelinjector i used for my 55 lbs Lockwood-Hiller untill now.
I am planning to make a new one with some more holes in it and to preheat the propane with a fuelpipe 5 times across the ubend before it enters the burningchamber.
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Berry
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re: Working together for the better (Injector Ideas and Test

Post by Berry » Fri Sep 08, 2006 6:24 pm

This is the fuelinjector i used for my 55 lbs Lockwood-Hiller untill now.
I am planning to make a new one with some more holes in it and to preheat the propane with a fuelpipe 5 times across the ubend before it enters the burningchamber.
Attachments
brandstofleiding01.JPG
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brandstofleiding02.JPG
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leo
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re: Working together for the better (Injector Ideas and Test

Post by leo » Fri Sep 08, 2006 8:16 pm

Berry I use similar injectors as you have only I never build something big.
Here is patent from Lockwood for liquid and gaseous fuel.
lockwood fuel injector
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fuelinjector1.jpg
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fuelinjector.jpg
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re: Working together for the better (Injector Ideas and Test

Post by leo » Fri Sep 08, 2006 8:32 pm

Berry if I was you I would use LPG for your Lockwood its a lot cheaper, and in such a big engine it will give no problems, only reckon with lower pressure

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