New injectors (VECTOR-JETS) and uber press

[Irvine.J]

Well all i've been a busy little bee. Sorry again for not being too present of late, but I have been reading all the threads. Recently I completed a successful test of a new series of injectors for liquid fueling a common valveless engine, providing good atomisation, in a purely Stainless steel injector.

The major difficulty I had was getting these made, and even so were far too expensive to be made by an engineering company, but I need them fast and lots of them. Completely disheartened by how difficult it was to do all of this and rely on others, my father reminded me... "If you want a job done properly, you gotta do it yourself..."
So, I went and bought this neat little ryobi drill press for a very very good price for what it is. (About 100 AU)

I've been trying hundreds of different ideas and designs of late, and the little SIG 12 V gasser pump was being used to pump the fuel. I started with a 0.018mm orifice size but the flow rate was too large for my engine, but it did atomise very well. So i'm now going with a single 0.0135mm or less drill size. - NOTE WELL - THE SIG 12 V GASSER PUMP IS A PIECE OF...FEACAL MATTER AND NOT WORTH THE MONEY I SPENT ON IT!
It leaked after the first day, and after about 10 minutes of operation (spread accross many days) it grenaded and shot a huge cloud of atomised kerosene everywhere! Get a better pump!

I have also sourced some excellent high pressure good amp draw fuel pumps now, that will never leak, and are good for hundreds of hours of operation. Along with the good pump, and these VECTOR-JETS, we have a serious throttleable flight system for any valveless, or simple ground liquid testing. I bet they would work pretty well in a big lockwood too :D
Best yet they are completely in-line. I can make them in a variety of spray patterns, and I have made a quick video of the first one working marvelously, which I will post when I get a few spare minutes.

Note I searched car, motorbike, motormower and boat injectors and NONE are good enough or right size, flow rate etc for a small pulsejet.

The biggest problem I had was drilling the excrutiatingly tiny 0.0135 mm hole in stainless so below is my uber dremmel press. The drill bit won't fit in any chucks I had available... a bit of plumbing tape fixed that!!!!
THIS UBERDREMMEL IS HILARIOUS!
DONT BE FOOLED! It goes dead straight, its fantastic.

Anyway, these are some pictures of the vector jets
before completion. They are ground down all by hand (As I have no lathe) and will be tig welded to a 1/4 inch SS pipe. I'll be making a few of these, and want to send a couple off for testing in engines such as a TP-180 and Lockwood too, post if your interested in getting your hands on one, it will be free of charge.

This dremmel press I haven't tried yet, but theres an engineering shop down the road that can drill the tiny orifice if I can't here. Also, i can make a variety of spray patterns. These will come with any HPX sold, and I will eventually sell them individually, as the atomise at fairly low pressure quite well.

[larry cottrill]

Thirteen thousandths mm (oops, sorry, I forgot the crucial half thousandth there at the end ;-) - that must be tricky to handle with your Drill Doctor(TM) when they get dull ...

Sounds expensive, too. But of course, it takes whatever it takes. I'd try one, but I don't know when I'd have the cash for a decent miniature pump of appropriate pressure to make it work.

Just curious: Why didn't you just get the usual Dremel drill press attachment? Maybe, insufficient stability / tracking accuracy (they are a pretty lightweight tool)? Or what?

L Cottrill

[Irvine.J]

Heya larry, well I did see those, and thought to myself...

"Hmm, well we all know the 1001 uses for ductape and cable ties." Basically, it was a test to see if the tiny drill could handle the stainless. Amazingly, I just tried it about 20 minutes ago, and proud to report it blitzed it. Just nailed right through the injector body in a neat, tiny little hole. I'm very happy indeed! Theres a bit of play on it but if you get the pull on the lever right you get a straight shot... meh what can you expect for such a dodgey setup.

I did see those dremel press thingy's, and they look real neat, and are probably 100 times more accurate then mine...and 100 times more expensive :-(

I get around by simply "Tapping" a punch right in the center so the drill finds its mark. Luckily, it worked without too much trouble at all. I've since been told there is an end attachment to that super tool to clamp onto those drill bits so I don't need the plumbing tape anymore. Excellent!

I'll chuck that vid of how the injector works soon.
Larry, just go to a car wrecker and ask them for a 12 V fuel pump, it will be cheap as chips. Also, if they say "Internal" or "External" it really doesn't matter, for internal ones you can just connect a hose and a clamp to the end of it, or, simply throw it into a bucket of kero and it will pump straight out. They pump EXTREMELY HARD, so i'd recommend some way to control the voltage like a 12V light dimming switch for example if you have no RC gear handy. Otherwise, plug it straight into your speed controller.

Larry, if you'll kindly email me your address, I'll send you one or two, just tell me the approximate spray angles you want. I also forgot to mention, they spray a 360* hollow cone :D
Best wishes to all.
James.

[larry cottrill]

Larry, just go to a car wrecker and ask them for a 12 V fuel pump, it will be cheap as chips. Also, if they say "Internal" or "External" it really doesn't matter, for internal ones you can just connect a hose and a clamp to the end of it, or, simply throw it into a bucket of kero and it will pump straight out. They pump EXTREMELY HARD, so i'd recommend some way to control the voltage like a 12V light dimming switch for example if you have no RC gear handy. Otherwise, plug it straight into your speed controller.

James et al -

I think an ideal way to control these would be to emulate how it used to be done in my old (1970) Porsche 914 - use a tap that bleeds off part of the flow back to the low-pressure side. This can give you a wide range of control without varying the pump at all! On the car this was done with a special diaphragm type regulator - its purpose was to provide absolutely stable pressure to the injectors as demand varied, BUT the exact same "looping" schematic could be used for throttling, if an appropriate valve can be found. (Of course, that might be a big "if" ;-)

Come to think of it, one of those regulators could still be used by cutting off the top of the housing and pressurising the load spring with a lever or cam instead of the provided screw adjustment! This little regulator was not very large, and probably weighed no more than a few ounces, with the outer shell being thin stamped steel. So, why not try it?

Thanks, James - I'll get my mailing address to you.

L Cottrill

[Irvine.J]

Larry wrote:

I think an ideal way to control these would be to emulate how it used to be done in my old (1970) Porsche 914 - use a tap that bleeds off part of the flow back to the low-pressure side. This can give you a wide range of control without varying the pump at all! On the car this was done with a special diaphragm type regulator - its purpose was to provide absolutely stable pressure to the injectors as demand varied, BUT the exact same "looping" schematic could be used for throttling, if an appropriate valve can be found. (Of course, that might be a big "if" ;-)

A good idea (as always Larry), however I did consider a similiar idea and came to the following conclusions... what do you think?
With the pump running at max power for its duration does 2 things.
1- Draws a much greater amount of power. Batterys would need to be larger with greater storage. I guess the idea of using less battery power at cruise would be optimal, as batt weight adds up significantly quickly.

2- Puts more strain on the pump and fuel fittings, reducing their life span, and increasing the risk of critical failure from a "blowout" during cruise. Those fuel pumps are rediculously high pressure.

I had thought that this "May" be the conclusive factors on using pump pressure to control flow rate. When at an Auto store they used a controllable voltage supply box that read amp draw, volts etc etc to show the amount of pressure and flow rates out of car injectors. They pump extremely hard and will probably never need be run max power even with a single 0.0135mm hole. I also found drill sizes down to #91 (0.0059) or something rediculous. but the jet speed would make for one hell of mist spray off that plate, and then pump pressure could be run at full.
I think your idea is good though, and would like to see you try it and post your results. You may find your getting too much flow even out of a common fuel pump with that tiny #80 hole at max power, so i'd like to see how you go. Is there any reason the conclusions I came to above may not be entirely accurate?

[Irvine.J]

Well, what do you think gents?
100% Stainless steel, 1/4 inch D.

"Pulsejet aviation atomising fuel injection at the tips of your fingers..." ???
Comments?

Amazing what you can do with a quality Tig.

There is two or three forumee's who will recieve one of these in the mail for testing. Data people I need data :D Anyone else want one?

Looking forward to your comments gents.

[larry cottrill]

Yes, James, I have to abmit it - that looks mighty good. Can't wait to try one out.

L Cottrill

[Mike Everman]

Sweeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeet. I can't wait to try it out.